Anti-DBH-SAP References

Anti-DBH-SAP (Cat. #IT-03)

265 entries found for : it-03

Noradrenergic innervations of the medial prefrontal cortex mediate empathy for pain in rats via the α1 and β receptors.

Yun-Fei L, Zhang J, Wang XQ, Peng JJ, Ling BF, Liu FT, Yang F, Dong G, Yu YQ (2022) Noradrenergic innervations of the medial prefrontal cortex mediate empathy for pain in rats via the α1 and β receptors. Behav Brain Res 10:113828. doi: 10.1016/j.bbr.2022.113828 Objective: To study the roles of the locus coeruleus (LC) to medial prefrontal cortex (mPFC) pathway in pain empathy in rats. Summary: Results indicate that noradrenergic innervations in the mPFC mediate empathy for pain in rats via the α1 and β receptors. Usage: Noradrenergic innervations of the mPFC were selectively eliminated through intra-mPFC injections of Anti-DBH-SAP. Related Products: Anti-DBH-SAP (Cat. #IT-03)

The role of BDNF-mediated neuroplasticity in cardiovascular regulation within the hypothalamus and brainstem

Thorsdottir DJ (2021) The role of BDNF-mediated neuroplasticity in cardiovascular regulation within the hypothalamus and brainstem. Univ Vermont, Dept Pharmacology 1387Thesis.

Summary: This PhD dissertation to determine the mechanism behind BDNF-mediated cardiovascular regulation.

Usage: Rats received bilateral NTS injections of vehicle or Anti-DBH-SAP, which selectively lesions catecholaminergic neurons. Treatment increased blood pressure in the GFP group but failed to affect blood pressure in the BDNF group.

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Neural circuitry underlying REM sleep: A review of the literature and current concepts

Wang YQ, Liu WY, Li L, Qu WM, Huang ZL (2021) Neural circuitry underlying REM sleep: A review of the literature and current concepts. Prog Neurobiol 204:102106. doi: 10.1016/j.pneurobio.2021.102106

Summary: To investigate the role of the LC in sleep the authors injected 0.3 µl of 192-Saporin (Cat. IT-01) or anti-DBH-SAP (Cat. #IT-03) at 1 µg/µl. They also used 0.3 µl of orexin-SAP (Cat. #IT-20) at either 90 ng/µl or 60 ng/µl in a separate group of animals. The results indicate that orexin innervation to the pons plays a role in arousal from sleep.

Related Products: Orexin-B-SAP (Cat. #IT-20), 192-IgG-SAP (Cat. #IT-01), Anti-DBH-SAP (Cat. #IT-03)

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Pain and depression comorbidity causes asymmetric plasticity in the locus coeruleus neurons

Llorca-Torralba M, Camarena-Delgado C, Suárez-Pereira I, Bravo L, Mariscal P, Garcia-Partida JA, López-Martín C, Wei H, Pertovaara A, Mico JA, Berrocoso E (2022) Pain and depression comorbidity causes asymmetric plasticity in the locus coeruleus neurons. Brain 145(1):154-167. doi: 10.1093/brain/awab239

Summary: There is strong comorbidity between chronic pain and depression. This study explores how this comorbidity occurs. The authors refer to published research that shows icv administration of anti-DBH-SAP or intra-LC administration of lidocaine dampened the evoked pain in conditions of long-term nerve-injury. However, icv injection of anti-DBH-SAP disrupts all noradrenergic nuclei (A1-A7), some of which contribute to sensorial hypersensitivity.

Related Products: Anti-DBH-SAP (Cat. #IT-03)

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A5 noradrenergic neurons and breathing control in neonate rats

Taxini CL, Marques DA, Bícego KC, Gargaglioni LH (2021) A5 noradrenergic neurons and breathing control in neonate rats. Pflugers Arch 473(6):859-872. doi: 10.1007/s00424-021-02550-1

Summary: In this study, the authors investigated the participation of A5 noradrenergic neurons in neonates (P7-8 and P14-15) in the control of ventilation during hypoxia and hypercapnia. data suggest that noradrenergic neurons of the A5 region in neonate rats do not participate in the control of ventilation under baseline and hypercapnic conditions, but exert an inhibitory modulation on breathing variability under hypoxic challenge in early life (P7-8).

Usage: Anti-DBH-SAP (420 ng/μL) or saporin (SAP, control) was injected into the A5 region of neonatal male Wistar rats.

Related Products: Anti-DBH-SAP (Cat. #IT-03)

Role of A1/A2 neurons in the dysregulation of vasopressin release and dilutional hyponatremia in liver disease

Aikins A, Little J, Cunningham, J (2021) Role of A1/A2 neurons in the dysregulation of vasopressin release and dilutional hyponatremia in liver disease. FASEB J 35(1). Experimental Biology 2021 Meeting Abstracts doi: 10.1096/fasebj.2021.35.S1.04975

Summary: Experiments suggest that A1/A2 neurons could be involved in the increased plasma AVP seen in male BDL rats as well as the decreased plasma osmolality.

Usage: Selective lesioning of the supraoptic nucleus (SON)-projecting A1/A2 norepinephrine neurons was achieved using anti-DBH-SAP.

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Activation of spinal dorsal horn astrocytes by noxious stimuli involves descending noradrenergic signaling

Kawanabe R, Yoshihara K, Hatada I, Tsuda M (2021) Activation of spinal dorsal horn astrocytes by noxious stimuli involves descending noradrenergic signaling. Mol Brain 14(1):79. doi: 10.1186/s13041-021-00788-5

Summary: Astrocytes are critical regulators of neuronal function in the central nervous system (CNS). Astrocytes in the spinal dorsal horn (SDH) increase intracellular Ca2+ levels following intraplantar injection of the noxious irritant, formalin, however the underlying mechanisms remain unknown. The authors investigated these mechanisms by focusing on the role of descending noradrenergic (NAergic). Activation of α1A-adrenaline receptors via descending LC-NAergic signals may be a common mechanism underlying astrocytic Ca2+ responses in the SDH evoked by noxious stimuli, including chemical irritants

Usage: Intrathecal treatment with Anti-DBH-SAP, which kills SDH-projecting NAergic neurons, attenuates formalin pain (5.0 µg/20 µl; Martin et al., 1999)

See: Martin WJ et al. Differential effects of neurotoxic destruction of descending noradrenergic pathways on acute and persistent nociceptive processing. Pain 80:57-65, 1999.

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Medullary noradrenergic neurons mediate hemodynamic responses to osmotic and volume challenges

Marques SM, Naves LM, Silva TME, Cavalcante KVN, Alves JM, Ferreira-Neto ML, de Castro CH, Freiria-Oliveira AH, Fajemiroye JO, Gomes RM, Colombari E, Xavier CH, Pedrino GR (2021) Medullary noradrenergic neurons mediate hemodynamic responses to osmotic and volume challenges. Front Physiol 12:649535. doi: 10.3389/fphys.2021.649535

Summary: The study sought to determine the role of noradrenergic neurons in hypertonic saline infusion (HSI)-induced hemodynamic recovery. Findings show that together the A1 and A2 neurons are essential to HSI-induced cardiovascular recovery in hypovolemia.

Usage: Medullary catecholaminergic neurons were lesioned by nanoinjection of Anti-DBH-SAP (0.105 ng·nl−1) into A1, A2, or both (LES A1; LES A2; or LES A1+A2, respectively). Sham rats received nanoinjections of unconjugated saporin in the same regions.

Related Products: Anti-DBH-SAP (Cat. #IT-03), Saporin (Cat. #PR-01)

Developments in understanding diffuse noxious inhibitory controls: pharmacological evidence from pre-clinical research

Kucharczyk MW, Valiente D, Bannister K (2021) Developments in understanding diffuse noxious inhibitory controls: pharmacological evidence from pre-clinical research. J Pain Res 14:1083-1095. doi: 10.2147/JPR.S258602

Summary: This review discusses the pharmacological manipulation interrogation strategies that have been used to examine the functionality of diffuse noxious inhibitory controls (DNIC) and descending control of nociception (DCN).

Usage: Anti-DBH-SAP is one of the drugs tested to influence DNIC expression. They reference a publication that reported that icv injection of Anti-DBH-SAP abolished DCN expression. Anti-DBH-SAP (5 μg/5 μl) was injected in the left ventricle. Lesion of the LC resulted in failure of DNIC, an effect that mimics what is observed behaviorally after chronic TBI.

See: Irvine KA et al. Loss of diffuse noxious inhibitory control after traumatic brain injury in rats: A chronic issue. Exp Neurol 333:113428, 2020.

Related Products: Anti-DBH-SAP (Cat. #IT-03)

Depletion of C1 neurons attenuates the salt-induced hypertension in unanesthetized rats.

Ribeiro N, Martins Sá RW, Antunes VR (2020) Depletion of C1 neurons attenuates the salt-induced hypertension in unanesthetized rats. Brain Res 1748:147107. doi: 10.1016/j.brainres.2020.147107

Objective: To determine if the ablation of C1 neurons mitigates high blood pressure induced by high-salt intake.

Summary: Data show that hypertension induced by high-salt intake is dependent on C1 neurons.

Usage: Bilateral injections of 2.4 ng/100 nl of Anti-DBH-SAP. The total number of TH+ neurons in the AS region was reduced by 37 ± 13% in the anti-DBH-SAP group when compared to control.

Related Products: Anti-DBH-SAP (Cat. #IT-03)

Noradrenaline signaling in the LPBN mediates amylin’s and salmon calcitonin’s hypophagic effect in male rats.

Boccia L, Le Foll C, Lutz TA (2020) Noradrenaline signaling in the LPBN mediates amylin's and salmon calcitonin's hypophagic effect in male rats. FASEB J 34(11):15448-15461. doi: 10.1096/fj.202001456RRR

Objective: To assess the phenotype of amylin activated LPBN (lateral parabrachial nucleus) neurons, especially to confirm the CGRPergic phenotype and to uncover the specific role of NA (noradrenaline) signaling from the AP to the LPBN.

Summary: The present study confirmed the central role of the LPBN in propagating amylin’s and sCT’s hypophagic action, and particularly the importance of AP → LPBN NA signaling in the mediation of this process, through the activation of LPBN (CGRP and non-CGRP) neurons.

Usage: The neuronal pathways used to process the physiological response to amylin were investigated using 50-ng injections of Anti-DBH-SAP (Cat. #IT-03) into the area postrema (AP) or 25 ng into the lateral parabrachial nucleus (Potes et al., 2010).

Related Products: Anti-DBH-SAP (Cat. #IT-03)

Loss of diffuse noxious inhibitory control after traumatic brain injury in rats: A chronic issue

Irvine KA, Sahbaie P, Ferguson AR, Clark JD (2020) Loss of diffuse noxious inhibitory control after traumatic brain injury in rats: A chronic issue. Exp Neurol 333:113428. doi: 10.1016/j.expneurol.2020.113428

Objective: To confirm hypothesis that dysfunctional descending noradrenergic and serotonergic pain control circuits may contribute to the loss of diffuse noxious inhibitory control (DNIC), a critical endogenous pain control mechanism, weeks to months after traumatic brain injury (TBI).

Summary: Results suggest that TBI causes maladaptation of descending nociceptive signaling mechanisms and changes in the function of both adrenergic and serotonergic circuits. Such changes could predispose those with TBI to chronic pain.

Usage: Anti-DBH-SAP (5 μg/5 μl) was injected in the left ventricle. Lesion of the LC resulted in failure of DNIC, an effect that mimics what is observed behaviorally after chronic TBI.

Related Products: Anti-DBH-SAP (Cat. #IT-03)

Adrenergic supersensitivity and impaired neural control of cardiac electrophysiology following regional cardiac sympathetic nerve loss

Tapa S, Wang L, Francis Stuart SD, Wang Z, Jiang Y, Habecker BA, Ripplinger CM (2020) Adrenergic supersensitivity and impaired neural control of cardiac electrophysiology following regional cardiac sympathetic nerve loss. Sci Rep 10:18801. doi: 10.1038/s41598-020-75903-y

Summary: The authors present a novel mouse model of regional cardiac sympathetic hypo-innervation utilizing Anti-DBH-SAP.

Usage: Either 5μL of 40 ng/μL Anti-DBH-SAP or Mouse IgG-SAP (control) was applied three times directly to the exposed apical/anterior surface of the heart.

Related Products: Anti-DBH-SAP (Cat. #IT-03), Mouse IgG-SAP (Cat. #IT-18)

Integration of peripheral and central systems in control of ingestive and reproductive behavior

Schneider J (2020) Integration of peripheral and central systems in control of ingestive and reproductive behavior. Oxford Research Encyclopedia of Neuroscience . Oxford University Press doi: 10.1093/acrefore/9780190264086.013.23

Summary: Highly glucose-sensitive cells in the ventrolateral medulla send catecholaminergic projections to the PVH. These projections can be selectively destroyed by Anti-DBH-SAP “DSAP” experiments show that catecholaminergic projections from glucose-sensitive cells in the ventrolateral medulla are necessary for all responses to glucoprivation, including increases in epinephrine secretion, glucocorticoid secretion, sex behavior, and food intake.

See: Ritter S et al. Hindbrain glucoregulatory mechanisms: Critical role of catecholamine neurons in the ventrolateral medulla. Physiol Behav 208:112568, 2019.

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Neuroendocrine and behavioral consequences of hyperglycemia in cancer

Vasquez JH, Borniger JC (2020) Neuroendocrine and behavioral consequences of hyperglycemia in cancer. Endocrinology 161(5):bqaa047. doi: 10.1210/endocr/bqaa047

Summary: Ablation of norepinephrine containing projections to the arcuate (via Anti-DBH-SAP injections) alters AgRP and neuropeptide (NPY) concentrations, leading to impairments in hypoglycemic (glucoprivic) or ghrelin-induced feeding.

Usage: Anti-DBH-SAP (bilateral 42-ng intracranial injections) was used in rats to investigate the role of hindbrain catecholamine afferents in increased ARC NPY and AgRP gene expression.

See: Fraley GS et al. Immunolesion of norepinephrine and epinephrine afferents to medial hypothalamus alters basal and 2-deoxy-D-glucose-induced neuropeptide Y and agouti gene-related protein messenger ribonucleic acid expression in the arcuate nucleus. Endocrinology 144(1):75-83, 2003.

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An age- and sex-dependent role of catecholaminergic neurons in the control of breathing and hypoxic chemoreflex during postnatal development.

Patrone LGA, Capalbo AC, Marques DA, Bícego KC, Gargaglioni LH (2020) An age- and sex-dependent role of catecholaminergic neurons in the control of breathing and hypoxic chemoreflex during postnatal development. Brain Res 1726:146508. doi: 10.1016/j.brainres.2019.146508

Objective: To discover the role of brainstem catecholaminergic (CA) neurons in the hypoxic ventilatory response (HVR).

Summary: Brainstem CA neurons modulate the HVR during the postnatal phase, and possibly thermoregulation during hypoxia.

Usage: Evaluation of brainstem CA neurons in the HVR during postnatal development in male and female rats through specific cell depletion with Anti-DBH-SAP (420 ng/nL) injected in the fourth ventricle.

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BDNF downregulates β-adrenergic receptor-mediated hypotensive mechanisms in the paraventricular nucleus of the hypothalamus.

Thorsdottir D, Cruickshank NC, Einwag Z, Hennig GW, Erdos B (2019) BDNF downregulates β-adrenergic receptor-mediated hypotensive mechanisms in the paraventricular nucleus of the hypothalamus. Am J Physiol Heart Circ Physiol 317(6):H1258-H1271. doi: 10.1152/ajpheart.00478.2019

Objective: To determine whether BDNF increases blood pressure in part by diminishing inhibitory hypotensive input from nucleus of the solitary tract (NTS) catecholaminergic neurons projecting to the PVN.

Summary: BDNF, a key hypothalamic regulator of blood pressure, disrupts catecholaminergic signaling between the NTS and the PVN by reducing the responsiveness of PVN neurons to inhibitory hypotensive β-adrenergic input from the NTS.

Usage: Bilateral NTS injections of sterile PBS (for control) or Anti-DBH-SAP (22 ng).

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Rostral ventrolateral medullary catecholaminergic neurones mediate irregular breathing pattern in volume overload heart failure rats.

Toledo C, Andrade DC, Díaz HS, Pereyra KV, Schwarz KG, Díaz-Jara E, Oliveira LM, Takakura AC, Moreira TS, Schultz HD, Marcus NJ, Del Rio R (2019) Rostral ventrolateral medullary catecholaminergic neurones mediate irregular breathing pattern in volume overload heart failure rats. J Physiol 597(24):5799-5820. doi: 10.1113/JP278845

Objective: To investigate the potential contribution of RVLM‐C1 neurons to irregular breathing.

Summary: Findings suggest that RVLM‐C1 neurons play a pivotal role in breathing irregularities in volume overload HF, and mediate the sympathetic responses induced by acute central chemoreflex activation.

Usage: Anti-DBH-SAP was used to selectively lesion RVLM‐C1 neurons. Reduction (∼65%) of RVLM‐C1 neurons resulted in attenuation of irregular breathing, decreased apnea‐hypopnea incidence and improved cardiac autonomic control.

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Corticolimbic stress regulatory circuits, hypothalamo–pituitary–adrenocortical adaptation, and resilience

Herman JP (2020) Corticolimbic stress regulatory circuits, hypothalamo–pituitary–adrenocortical adaptation, and resilience. Chen A (Ed.): Stress Resilience 291-309. Academic Press doi: 10.1016/B978-0-12-813983-7.00019-7

Summary: Review. Immunolesion of paraventricular nucleus (PVN)-projecting norepinephrine (NE) neurons with Anti-DBH-SAP attenuates acute stress reactivity (interestingly, to restraint), but it does not inhibit somatic or HPA axis responses to stress in any simple way (Flak et al.). PVN-projecting NE neurons appear to be responsible for acute responses to systemic stressors, but they do not appear to be important in mediating effects of chronic stress (Ritter et al.).

Usage: Flak et al. injected 8.82 ng of Anti-DBH-SAP into the PVN. Ritter et al. injected 42 ng into the PVN.

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Astroglia in Alzheimer’s Disease.

Verkhratsky A, Parpura V, Rodriguez-Arellano J, Zorec R (2019) Astroglia in Alzheimer’s Disease. (eds. Verkhratsky A, Ho M, Zorec R, Parpura V). In: Advances in Experimental Medicine and Biology: Neuroglia in Neurodegenerative Diseases. 1175:273-324. Springer, Singapore. doi: 10.1007/978-981-13-9913-8_11

Summary: A review of the tools for creating animal models of Alzheimer's Disease. 192-IgG-SAP binds selectively and irreversibly to low-affinity nerve growth factor receptor interrupting cholinergic neuronal protein synthesis was employed. Anti-DBH-SAP binds dopamine-β-hydroxylase, which is not only localized mainly in the cytosol, but also at the plasma membrane surface of noradrenergic neurons. Anti-DBH-SAP produced specific and dose-dependent depletions of locus coeruleus neurons, with no effects on other cholinergic, dopaminergic or serotonergic neuronal populations. The possibility to induce a partial or total noradrenergic loss (by varying the injected dose) makes this immunotoxic approach an ideal model to study events within the noradrenergic projection system, as they occur during age-related demise of locus coeruleus in humans.

Related Products: 192-IgG-SAP (Cat. #IT-01), Anti-DBH-SAP (Cat. #IT-03)

Central glucagon-like peptide-1 receptor signaling via brainstem catecholamine neurons counteracts hypertension in spontaneously hypertensive rats.

Katsurada K, Nakata M, Saito T, Zhang B, Maejima Y, Nandi SS, Sharma NM, Patel KP, Kario K, Yada T (2019) Central glucagon-like peptide-1 receptor signaling via brainstem catecholamine neurons counteracts hypertension in spontaneously hypertensive rats. Sci Rep 9(1):12986. doi: 10.1038/s41598-019-49364-x

Objective: To determine mechanisms for antihypertensive effect of GLP-1R agonists.

Summary: The central GLP-1R signaling via NTS DBH neurons counteracts the development of hypertension in SHR, accompanied by attenuated sympathetic nerve activity.

Usage: Anti-DBH-SAP or Blank-SAP was injected into NTS bilaterally (6 ng/200 nl).

Related Products: Anti-DBH-SAP (Cat. #IT-03), Blank-SAP (Cat. #IT-21)

Hindbrain glucoregulatory mechanisms: Critical role of catecholamine neurons in the ventrolateral medulla.

Ritter S, Li A-J, Wang Q (2019) Hindbrain glucoregulatory mechanisms: Critical role of catecholamine neurons in the ventrolateral medulla. Physiol Behav 208:112568. doi: 10.1016/j.physbeh.2019.112568

Objective: To explore circuitry and potential glucose-sensing mechanisms that contribute to the functions of glucoregulatory catecholamine neurons in the ventrolateral medulla

Summary: Selective lesion of hindbrain catecholamine neurons abolishes glucoprivic elicitation of key counterregulatory responses. Selective chemogenetic activation of specific catecholamine populations elicits these responses.

Related Products: Anti-DBH-SAP (Cat. #IT-03), NPY-SAP (Cat. #IT-28)

The role of the brain in the regulation of peripheral noradrenaline-producing organs in rats during morphogenesis.

Murtazina AR, Nikishina YO, Dil'mukhametova LK, Sapronova AY, Ugrumov MV (2019) The role of the brain in the regulation of peripheral noradrenaline-producing organs in rats during morphogenesis. Dokl Biochem Biophys 486(1):243-246. doi: 10.1134/S1607672919030207 Related Products: Anti-DBH-SAP (Cat. #IT-03)

Morphological analysis for neuronal pathway from the hindbrain ependymocytes to the hypothalamic kisspeptin neurons.

Deura C, Minabe S, Ikegami K, Inoue N, Uenoyama Y, Maeda KI, Tsukamura H (2019) Morphological analysis for neuronal pathway from the hindbrain ependymocytes to the hypothalamic kisspeptin neurons. J Reprod Dev 65(2):129-137. doi: 10.1262/jrd.2018-122

Objective: To examine the existence of a neuronal pathway from the hindbrain ependymocytes to kisspeptin neurons in the arcuate nucleus (ARC) and anteroventral periventricular nucleus (AVPV).

Summary: The hindbrain ependymocytes have neuronal connections with the kisspeptin neurons, most probably via hindbrain noradrenergic and CRH neurons to relay low energetic signals for regulation of reproduction.

See: I'Anson H et al. Immunotoxic destruction of distinct catecholaminergic neuron populations disrupts the reproductive response to glucoprivation in female rats. Endocrinology 144(10):4325-4331, 2003.

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Noradrenergic depletion causes sex specific alterations in the endocannabinoid system in the Murine prefrontal cortex.

Urquhart MA, Ross JA, Reyes BAS, Nitikman M, Thomas SA, Mackie K, Van Bockstaele EJ (2019) Noradrenergic depletion causes sex specific alterations in the endocannabinoid system in the Murine prefrontal cortex. Neurobiology of Stress 10:100164. doi: 10.1016/j.ynstr.2019.100164

Objective: To determine the effects of NE depletion on the eCB system.

Summary: The results suggest that the endocannabinoids (eCB) system may be more responsive in males than females under conditions of NE perturbation, thus having potential implications for sex-specific treatment strategies of stress-related psychiatric disorders.

Usage: The authors used a DBH knockout model and DSP-4 (a compound that depletes endogenous norepinephrine and enhances release of [3H]norepinephrine). More specific mechanisms for further corroboration could be undertaken, such as using Anti-DBH-SAP to provide a more complete lesion compared to DSP-4.

Related Products: Anti-DBH-SAP (Cat. #IT-03)

Brainstem pre-sympathetic neurons contribute to irregular breathing patterns in volume overload heart failure.

Toledo C, Andrade DC, Del Rio R (2019) Brainstem pre-sympathetic neurons contribute to irregular breathing patterns in volume overload heart failure. FASEB J 33(1):lb630. Experimental Biology 2019 Meeting Abstracts doi: 10.1096/fasebj.2019.33.1_supplement.lb630

Objective: To investigate the contribution of RVLM-C1 neurons on breathing disorders in chronic heart failure (CHF).

Summary: RVLM-C1 neurons play a critical role in the maintenance of altered breathing patterns in CHF rats and highlighted their contribution to the worsening of cardiac function during central chemoreflex activation. DBH-SAP treatment decreased active expiration in CHF rats and deleterious effects of central chemoreflex activation on diastolic cardiac function and cardiac autonomic control were blunted.

Usage: Stereotaxic bilateral injections of Anti-DBH-SAP (5 ng/150 nl).

Related Products: Anti-DBH-SAP (Cat. #IT-03)

Spinal α2-adrenoceptors and neuropathic pain modulation; therapeutic target.

Bahari Z, Meftahi GH (2019) Spinal α2-adrenoceptors and neuropathic pain modulation; therapeutic target. Br J Pharmacol 176(14):2366-2381. doi: 10.1111/bph.14580

Objective: To provide an an overview of the cellular mechanisms through which brainstem adrenergic descending inhibitory processing can alter spinal pain transmission to the higher centres, and how these pathways change in neuropathic pain conditions focusing on the role of spinal α2‐adrenoceptors in the spinal dorsal horn.

Summary: The α2‐adrenoceptor agonist may be useful to treat neuropathic pain.

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Noradrenergic terminals are the primary source of α2-adrenoceptor mediated dopamine release in the medial prefrontal cortex.

Devoto P, Flore G, Saba P, Scheggi S, Mulas G, Gambarana C, Spiga S, Gessa GL (2019) Noradrenergic terminals are the primary source of α2-adrenoceptor mediated dopamine release in the medial prefrontal cortex. Prog Neuropsychopharmacol Biol Psychiatry 90:97-103. doi: 10.1016/j.pnpbp.2018.11.015

Objective: To clarify the relative contribution of dopamine (DA) release from noradrenergic and dopaminergic terminals to DA output induced by blockade of α2-adrenoreceptors and the norepinephrine transporter.

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Ablation of brainstem C1 neurons improves cardiac function in volume overload heart failure.

Andrade DC, Toledo C, Díaz HS, Lucero C, Arce-Álvarez A, Oliveira LM, Takakura AC, Moreira TS, Schultz HD, Marcus NJ, Alcayaga J, Del Rio R (2019) Ablation of brainstem C1 neurons improves cardiac function in volume overload heart failure. Clin Sci (Lond) 133(3):393-405. doi: 10.1042/CS20180589

Objective: To determine the role played by RVLM-C1 neurons in cardiac autonomic imbalance, arrhythmogenesis and cardiac dysfunction in volume overload-induced heart failure.

Summary: RVLM-C1 neurons were selectively ablated using Anti-DBH-SAP and measures of cardiacautonomictone, function, and arrhythmia incidence were evaluated. Cardiac autonomic imbalance, arrhythmogenesis and cardiac dysfunction were present in HF rats and improved after Anti-DBH-SAP treatment.

Usage: 7.5ng/100nl of sterile saline solution was injected bilaterally into the RVLM.

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Dissociable effects of noradrenergic and cholinergic lesions of anterior cingulate cortex on distractibility

McGaughy JA, Hutchins DJ, Pimentel AJ, Pimentel CS, Swaine JA (2018) Dissociable effects of noradrenergic and cholinergic lesions of anterior cingulate cortex on distractibility. Neuroscience 2018 Abstracts 238.14 / ZZ15. Society for Neuroscience, San Diego, CA.

Summary: Prior data from our lab and others has shown that that the anterior cingulate cortex (ACC) of the rat is critically involved in many aspects of executive function and cognitive control. Previously, we have shown that excitotoxic lesions of the ACC produced deficits in the ability of male rats to filter salient distractors. Additionally, these same subjects were unable to reverse reinforcement contingencies when tested with complex stimuli (Newman and McGaughy 2011). These deficits in filtering were not attributable to impairments in conditional discrimination learning, impairments in reversal learning with uni-dimensional stimuli or a general distractibility to conspicuous, irrelevant stimuli. In the present study, male, Long-Evans rats were used to determine if lesions to the noradrenergic or cholinergic afferents to ACC could recapitulate the effects of excitotoxic lesions in the same area. Lesions were produced by infusion into rostral ACC of dopamine β hydroxylase saporin or 192 IgG-saporin to deplete norepinephrine or acetylcholine, respectively. After two weeks of recovery from surgery, rats were tested in an intradimensional/extradimensional set-shifting task. This test was selected because of it's utility in translational neuroscience and it’s sensitivity to several aspects of executive function including susceptibility to salient distractors, the ability to form an attentional set, the ability to shift an attentional set and reversal learning. Preliminary data show that noradrenergic, but not cholinergic lesions recapitulate some, but not all, of the impairments found after excitotoxic lesion of ACC. Specifically noradrenergic lesioned rats were more susceptible to salient distractors than sham-lesioned rats. In contrast to the effects of excitotoxic lesions, noradrenergic lesions did not impair the ability to reverse reinforcement contingencies when using complex stimuli containing salient, irrelevant stimulus dimensions. The extent of the lesions to ACC were assessed using markers for norepinephrine transporters and acetylcholinesterase. Together these data support the hypothesis that norepinephrine in the ACC is critically involved in the ability to filter salient distractors. The significance of these findings will be discussed in terms of the relevance of these data to the treatment of several neuropsychiatric disorders including attention deficit hyperactivity disorder, depression and addiction.

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Noradrenergic modulation of the orbitofrontal cortex mediates flexibility of goal-directed behavior

Cerpa J-C, Marchand AR, Wolff M, Parkes SL, Coutureau E (2018) Noradrenergic modulation of the orbitofrontal cortex mediates flexibility of goal-directed behavior. Neuroscience 2018 Abstracts 325.09 / DDD22. Society for Neuroscience, San Diego, CA.

Summary: For an organism, knowledge of the consequences of its actions and the ability to assign a value to these consequences are both crucial processes allowing an appropriate goal-directed response. The major role of prefrontal regions, e.g. insular and medial prefrontal cortices, for these processes has been very well described. However, the mechanism by which the organism quickly adapt this goal-directed response to unexpected environmental changes remains unknown. It is possible to study this ability using instrumental learning. Typically, during an initial phase, an animal must associate voluntary actions with the delivery of rewarding outcomes. Then, during a reversal phase, the animal must respond flexibly to a modification of these associations. Using this task and chemogenetic tools allowing specific inhibition of cerebral regions, we have recently demonstrated a crucial role of the ventrolateral orbitofrontal cortex (vlOFC) for flexible response adaptation during the reversal phase (Parkes et al., 2017). In the present study, we focused on the noradrenaline (NA) input to the vlOFC which has been commonly implicated in flexibility-requiring tasks. In a first experiment, using a toxin (anti-DβH saporin) we selectively depleted noradrenergic fibers in the vlOFC and showed a deficit of behavioral flexibility. Notably, this effect was not only specific to the reversal phase but also to vlOFC input since a similar depletion restricted to the medial portion of the prefrontal cortex had no effect. Using an intersectional chemogenetic approach aiming at selectively targeting the locus cœruleus (LC) input to the vlOFC, we are deciphering the time course of the involvement of this pathway during behavioural flexibility. Taken together, these results demonstrate a central role for noradrenaline input to the vlOFC in behavioural flexibility and reinforce the idea that the LC exerts a strong modulation of OFC functions.

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Noradrenergic hypothesis linking neurodegeneration-based cognitive decline and astroglia.

Leanza G, Gulino R, Zorec R (2018) Noradrenergic hypothesis linking neurodegeneration-based cognitive decline and astroglia. Front Mol Neurosci 11:254. doi: 10.3389/fnmol.2018.00254

Objective: To examine noradrenergic dysfunction in AD-related cognitive decline in humans and its potential involvement in AD pathology and disease progression.

Summary: The authors discuss noradrenergic dysfunction in AD-related cognitive decline. The research focuses on animal models to allow the validation of the noradrenergic hypothesis of AD, including those based upon the Anti-DBH-SAP-mediated ablation of LC. The article also addresses how astrocytes may participate in the regulation of neurogenesis, a new strategy for preventing LC neuron loss.

Usage: DBH (–/–) knockout mice do not seem to offer the possibility to obtain partial or graded neurotransmitter depletions. In light of these limitations, the authors used Anti-DBH-SAP which is able to target noradrenergic neurons in the LC with unprecedented selectivity and efficiency. Anti-DBH-SAP was injected bilaterally into the LC.

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Involvement of median preoptic nucleus and medullary noradrenergic neurons in cardiovascular and sympathetic responses of hemorrhagic rats

Naves LM, Marques SM, Mourão AA, Fajemiroye JO, Xavier CH, de Castro CH, Rebelo ACS, Rosa DA, Gomes RM, Colombari E, Pedrino GR (2018) Involvement of median preoptic nucleus and medullary noradrenergic neurons in cardiovascular and sympathetic responses of hemorrhagic rats. Sci Rep 8:11276. doi: 10.1038/s41598-018-29310-z

Objective: To evaluate the involvement of median preoptic nucleus (MnPO) and medullary noradrenergic neurons (A1 and A2) in HSS-induced cardiovascular and sympathetic responses in hemorrhagic rats.

Summary: The recovery of MAP and HSS-induced sympathoinhibition in hemorrhaged rats depend on intact neural projections from A1 and A2 to MnPO.

Usage: In order to achieve A1 and/or A2 neuronal lesions, Anti-DBH-SAP (100 nL, 0.105 ng·nL−1 ) was nanoinjected into the CVLM and NTS region, respectively. In sham groups, the equimolar of Saporin (100 nL, 0.022 ng·nL−1 ) was nanoinjected into the same site.

Related Products: Anti-DBH-SAP (Cat. #IT-03), Saporin (Cat. #PR-01)

Why I can’t say “no” to hindbrain catecholamine neurons

Ritter S (2018) Why I can’t say “no” to hindbrain catecholamine neurons. Appetite 126:210. doi: 10.1016/j.appet.2018.02.035 Related Products: Anti-DBH-SAP (Cat. #IT-03)

Mo1545 – Vagal nerve modulates the effects of esophageal acid on the periaqueductal gray functional connectivity in a rat model

Sanvanson P, Li Z, Ward BD, Shaker R (2018) Mo1545 - Vagal nerve modulates the effects of esophageal acid on the periaqueductal gray functional connectivity in a rat model. Gastroenterology 154:S-747-S-748. doi: 10.1016/S0016-5085(18)32596-4 Related Products: Anti-DBH-SAP (Cat. #IT-03)

Mo1546 – Neonatal colon inflammation-induced increases in pituitary adenylate cyclase activating peptide expression in the parabrachial nucleus contributes to reduced meal consumption, to increased meal-induced aversive and anxiety-like behaviors in adult rats

Winston J (2018) Mo1546 - Neonatal colon inflammation-induced increases in pituitary adenylate cyclase activating peptide expression in the parabrachial nucleus contributes to reduced meal consumption, to increased meal-induced aversive and anxiety-like behaviors in adult rats. Gastroenterology 154:S-748. doi: 10.1016/S0016-5085(18)32597-6

Summary: Infusion of Anti-DBH-SAP into the dorsal vagal complex significantly increased meal volumes and increased open field activity compared to IgG-saporin treatment.

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Essential role of hippocampal noradrenaline in the regulation of spatial working memory and TDP‐43 tissue pathology

Pintus R, Riggi M, Cannarozzo C, Valeri A, de Leo G, Romano M, Gulino R, Leanza G (2018) Essential role of hippocampal noradrenaline in the regulation of spatial working memory and TDP‐43 tissue pathology. J Comp Neurol 526:1131-1147. doi: 10.1002/cne.24397

Objective: To determine the noradrenergic contribution to cognitive and histopathological changes in Alzheimer’s Disease.

Summary: Integrity of ascending noradrenergic inputs to the hippocampus may be required for the regulation of specific aspects of learning and memory and to prevent TDP-43 tissue pathology.

Usage: Anti-DBH-SAP was used at a dose of 0.50 µg dissolved in sterile PBS.

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Brainstem catecholaminergic neurones and breathing control during postnatal development in male and female rats.

Patrone LGA, Biancardi V, Marques DA, Bícego KC, Gargaglioni LH (2018) Brainstem catecholaminergic neurones and breathing control during postnatal development in male and female rats. J Physiol 596(15):3299-3325. doi: 10.1113/JP275731

Objective: To determine the role of the brainstem CA system in ventilatory control under normocapnic and hypercapnic conditions during different phases of development (P7-8, P14-15 and P20-21) in male and female Wistar rats.

Summary: Brainstem CA neurones produce a tonic inhibitory drive that affects breathing frequency in P7-8 rats and provide an inhibitory drive during hypercapnic conditions in both males and females at P7-8 and P14-15.

Usage: Anti-DBH-SAP (420 ng/μL – 1 μL for P0-1; 1.5 μL for P7-8; 2.0 μL for P13-14) was injected into the 4th ventricle of neonatal Wistar rats of both sexes. Control rats were injected with vehicle (PBS, 0.01 M, pH 7.4) or unconjugated saporin (Cat. #PR-01), with respective volumes for each age, as described for the Anti-DBH-SAP group. All injections were performed using a microinjector pump over a period of 5 min to allow drug diffusion.

Related Products: Anti-DBH-SAP (Cat. #IT-03), Saporin (Cat. #PR-01)

Modelling the dopamine and noradrenergic cell loss that occurs in Parkinson’s disease and the impact on hippocampal neurogenesis.

Ermine CM, Wright JL, Frausin S, Kauhausen JA, Parish CL, Stanic D, Thompson LH (2018) Modelling the dopamine and noradrenergic cell loss that occurs in Parkinson's disease and the impact on hippocampal neurogenesis. Hippocampus 28(5):327-337. doi: 10.1002/hipo.22835

Objective: The mechanisms underlying reduced neurogenesis in Parkinson's Disease (PD) are not well established. The authors tested the hypothesis that noradrenergic and dopaminergic depletion, as occurs in PD, impairs hippocampal neurogenesis.

Summary: Mechanisms of neurotransmitter-based regulation of cognition and hippocampal neurogenesis may well overlap under certain conditions but the present results do not suggest a simple relationship associated with the degeneration of the two most prominently affected transmitter systems in PD.

Usage: Rats received 1 mcg Anti-DBH-SAP icv.

Related Products: Anti-DBH-SAP (Cat. #IT-03)

Catecholaminergic projections into an interconnected forebrain network control the sensitivity of male rats to diet-induced obesity

Lee SJ, Jokiaho AJ, Sanchez-Watts G, Watts AG (2018) Catecholaminergic projections into an interconnected forebrain network control the sensitivity of male rats to diet-induced obesity. Am J Physiol Regul Integr Comp Physiol 314(6):R811-R823. doi: 10.1152/ajpregu.00423.2017

Objective: To investigate the role of hindbrain catecholamine neuron pathways and their contribution to long-term energy homeostasis by controlling obesogenic sensitivity to a high-fat, high sucrose choice diet.

Summary: The authors show that catecholamine neurons (primarily in the VLM and NTS) convey essential feedback signals to enable long-term adaptive control of energy metabolism when animals consume a predominantly carbohydrate diet. This is the first report specifically associating this projection system with the long-term control of adiposity.

Usage: Catecholaminergic projections to the PVH and related parts of the forebrain were lesioned with bilateral injections each consisting of 42 ng/200 nL of Anti-DBH-SAP or equimolar amounts of control Mouse IgG-SAP.

Related Products: Anti-DBH-SAP (Cat. #IT-03), Mouse IgG-SAP (Cat. #IT-18)

Vagus nerve stimulation dependent enhancement of motor cortex plasticity requires noradrenergic innervation

Hulsey D, Shedd M, Mong J, Rennaker RL, Hays SA, Kilgard MP (2017) Vagus nerve stimulation dependent enhancement of motor cortex plasticity requires noradrenergic innervation. Neuroscience 2017 Abstracts 317.06 / HH5. Society for Neuroscience, Washington, DC.

Summary: Pairing forelimb movements with vagus nerve stimulation (VNS) drives robust plasticity within primary motor cortex (M1). VNS activates cholinergic circuits, which are required for VNS-depended enhancement of plasticity. However, there may be multiple neuromodulatory mechanisms required for VNS-dependent enhancement of plasticity. Norepinephrine regulates plasticity, and the noradrenergic locus coeruleus is driven vigorously by VNS. However, the role of norepinephrine in VNS-dependent enhancement of plasticity is unknown. We hypothesize that noradrenergic innervation of M1 and/or basal forebrain is necessary for M1 plasticity associated with VNS pairing. To test this, we trained rats on a skilled lever press task emphasizing use of the proximal forelimb. After demonstrating proficiency on the task, rats received M1 injections of vehicle or DBH-Saporin to selectively deplete norepinephrine in motor cortex, and underwent implantation of a stimulating cuff electrode on the vagus nerve. Sham and NE- lesioned rats resumed training one week after surgery. After returning to pre-surgical performance, both groups received 10 sessions of training with VNS paired on successful trials. Intracortical microstimulation was performed to derive M1 maps within 24 hours of the final training session. Initial data suggests that sham lesioned animals who receive VNS pairing with successful trials show a robust expansion of proximal forelimb movements represented in M1. Noradrenergic lesion of M1 blocks this VNS- dependent expansion of proximal forelimb representation, indicating that cortical norepinephrine innervation is necessary for VNS driven plasticity. Ongoing experiments will determine whether noradrenergic input to the central cholinergic systems is required for VNS-dependent enhancement of plasticity.

Related Products: Anti-DBH-SAP (Cat. #IT-03)

Changes in the secretory activity of organs producing noradrenaline upon inhibition of its synthesis in neonatal rat brain

Murtazina AR, Dilmukhametova LK, Nikishina YO, Sapronova AY, Volina EV, Ugrumov MV (2017) Changes in the secretory activity of organs producing noradrenaline upon inhibition of its synthesis in neonatal rat brain. Russ J Dev Biol 48:295-300.. doi: 10.1134/S1062360417050058

Summary: This study demonstrates that synthesis of noradrenaline after destruction of noradrenergic neurons was switched off by stereotactically injecting Anti-DBH-SAP (0.5 μg/2 μL; Cat #IT-03) into the lateral brain ventricle of neonatal rats. Forty-eight hours after treatment, expression of the tyrosine hydroxylase (TH) gene in the brain was 56% higher, 53% higher in the adrenal glands, and 55.8% higher in the organ of Zuckerkandl as compared to control (2 μL of 0.9% NaCl).

Related Products: Anti-DBH-SAP (Cat. #IT-03)

Role of A5 noradrenergic neurons in the chemoreflex control of respiratory and sympathetic activities in unanesthetized conditions

Taxini CL, Moreira TS, Takakura AC, Bicego KC, Gargaglioni LH, Zoccal DB (2017) Role of A5 noradrenergic neurons in the chemoreflex control of respiratory and sympathetic activities in unanesthetized conditions. Neuroscience 354:146-157.. doi: 10.1016/j.neuroscience.2017.04.033

Summary: The authors utilize Anti-DBH-SAP (Cat. #IT-03) to investigate the involvement of the A5 noradrenergic neurons to the basal and chemoreflex control of the sympathetic and respiratory activities in unanesthetized conditions.

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Depletion of rostral ventrolateral medullary catecholaminergic neurons impairs the hypoxic ventilatory response in conscious rats.

Malheiros-Lima M, Takakura A, Moreira T (2017) Depletion of rostral ventrolateral medullary catecholaminergic neurons impairs the hypoxic ventilatory response in conscious rats. Neuroscience 351:1-14.. doi: 10.1016/j.neuroscience.2017.03.031

Related Products: Anti-DBH-SAP (Cat. #IT-03)

Plasticity of central and peripheral sources of noradrenaline in rats during ontogenesis.

Bondarenko N, Dilmukhametova L, Kurina A, Murtazina A, Sapronova A, Sysoeva A, Ugrumov M (2017) Plasticity of central and peripheral sources of noradrenaline in rats during ontogenesis. Biochemistry (Mosc) 82:373-379.. doi: 10.1134/S0006297917030166

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The locus coeruleus: a potential link between cerebrovascular and neuronal pathology in Alzheimer’s disease.

Kelly SC, Nelson PT, Counts SE (2016) The locus coeruleus: a potential link between cerebrovascular and neuronal pathology in Alzheimer’s disease. Neuroscience 2016 Abstracts 786.11 / H7. Society for Neuroscience, San Diego, CA.

Summary: Noradrenergic locus coeruleus (LC) neuron loss is a major feature of Alzheimer’s disease (AD). The LC is the primary source of norepinephrine (NE) in the forebrain, where it modulates attention and memory in vulnerable cognitive regions such as prefrontal cortex and hippocampus. Furthermore, LC-mediated NE signaling is thought to play a role in blood brain barrier maintenance and neurovascular coupling, suggesting that LC degeneration may impact the high comorbidity of cerebrovascular disease (CVD) and AD. However, the extent to which LC projection system degeneration occurs in the earliest stages of AD is not fully characterized to date. To address these issues, we analyzed LC tissue samples from University of Kentucky AD Center subjects who died with a premortem diagnosis of no cognitive impairment (NCI) and Braak stages 0-II at autopsy, NCI subjects with Braak stages III-V thought to be in a preclinical AD (PCAD) stage, and subjects with mild cognitive impairment (MCI) or mild AD (n = 5-6 cases/group). Paraffin-embedded pontine tissue blocks containing the LC were cut at 20µm, immunostained with tyrosine hydroxylase (TH, a marker for NE synthesis), and analyzed by stereology to estimate total LC neuron number (total number of neuromelanin-containing LC neurons) and the percentage of TH+ LC neurons. Preliminary analysis reveal a ~20% loss of both total and TH+ LC neurons in PCAD (p = 0.08), a ~30-35% loss of these neurons in MCI (p < 0.05), and a ~45-50% loss of total and TH+ neurons in AD (p < 0.01) compared to NCI. Studies were also performed to compare additional LC neuronal pathologies (phospho-tau, TDP-43, and 8dOHG) in the diagnostic groups. A substantial increase in 8dOHG and phospho-tau is observed in PCAD compared to NCI. The morphometric data will be correlated with postmortem neuropathologic and CVD variables (e.g., microinfarcts and cerebral amyloid angiopathy) to gauge the relationship between LC neurodegeneration and cerebral AD and vascular pathology. To model these relationships in vivo, we stereotactically lesioned LC projection neurons innervating the PFC, a major LC projection zone, in the TgF344-19 rat model of AD (6 months old) using the noradrenergic immunotoxin, dopamine-β-hydroxylase-saporin, or a control lesion (n = 8/group). Prior to sacrifice at 9 months, immunotoxin- and control-lesioned rats will be tested behaviorally on the Barnes maze task. Postmortem PFC will be analyzed for LC fiber innervation, NE and NE metabolite levels, CVD pathology and AD-like pathology. Taken together, these data will shed light on the multifactorial noradrenergic pathways contributing to neuronal and vascular pathologies during the onset of AD.

Related Products: Anti-DBH-SAP (Cat. #IT-03)

ATS Poster of the Year Winner. Read the featured article in Targeting Trends.

Catecholaminergic innervation and the neuronal activation of hypothalamic glucose sensitive regions during rapid- and slow-onset hypoglycemia in adult male rats..

Jokiaho A, Watts AG (2016) Catecholaminergic innervation and the neuronal activation of hypothalamic glucose sensitive regions during rapid- and slow-onset hypoglycemia in adult male rats.. Neuroscience 2016 Abstracts 256.21 / CCC20. Society for Neuroscience, San Diego, CA.

Summary: Hypoglycemic counterregulation is mediated by glucosensors located in the hypothalamus, hindbrain, and portal-mesenteric veins. But which are engaged is rate-dependent, with portal vein sensors being obligatory for slow- but not rapid-onset hypoglycemia. Slow-onset hypoglycemia is particularly prevalent with insulin therapy in type 1 diabetes. We have previously shown that hindbrain-to-hypothalamus catecholaminergic (CA) projections are required for sympathoadrenal responses to slow- but not rapid-onset hypoglycemia, and that rapid- but not slow-onset hypoglycemia significantly increases CA/Fos colocalization in the ventrolateral medulla. These results show that the organization of a hypoglycemia-responsive brain networks is rather complex, and involves a set of what are likely parallel but interactive networks, each of which is responsible for controlling epinephrine, glucagon, and glucocorticoid responses. We now examine how various forebrain cell groups known to be important for glycemic regulation respond to , and how these responses are impacted by removing hindbrain-to-hypothalamus CA projections using injections of the immunotoxin, saporin conjugated to anti-DBH (DSAP) into the hypothalamic paraventricular nucleus (PVH). These injections remove CA inputs to the PVH and other regions within the medial hypothalamus. We then examined whether DSAP lesions affected Fos responses to slow- and rapid-onset insulin-induced hypoglycemia in key forebrain regions. We found that removing CA innervation differentially influences regional hypothalamic Fos responses to slow- and rapid-onset insulin-induced hypoglycemia. Rapid-onset hypoglycemia produced significantly greater Fos activations in the medial and lateral parvocellular and lateral parts of the PVH, parts of the lateral hypothalamus (LHA), the bed nucleus of the stria terminalis that was significantly reduced in all these regions with DSAP lesions. Of particular interest was the altered Fos in LHA regions that contain orexin neurons. We found that 27% of Fos activated neurons colocalized with orexin neurons in rapid-onset hypoglycemia, but this colocalization was significantly reduced by DSAP lesions. Furthermore we used a retrogradely transported polysynaptic neurotropic virus (PRV-152) injected into adrenal gland to show that 25% of PRV-labeled neurons in the LHA colocalized with orexin neurons. These results show that hindbrain-to-hypothalamus CA projections provide hypoglycemia-related information to regions of the forebrain in a rate-dependent way, with orexin neurons playing a particularly prominent role for sympathoadrenal responses.

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Diacylglycerol lipase-α expression increases in the coeruleo-cortical pathway in dopamine-β-hydroxylase knockout mice as well as rats treated with DSP-4

Urquhart M, Reyes BAS, Thomas SA, Mackie K, Van Bockstaele EJ (2016) Diacylglycerol lipase-α expression increases in the coeruleo-cortical pathway in dopamine-β-hydroxylase knockout mice as well as rats treated with DSP-4. Neuroscience 2016 Abstracts 77.09 / AAA24. Society for Neuroscience, San Diego, CA.

Summary: Endocannabinoids are involved in the regulation of many physiological processes including behavioral responses to stress. Endocannabinoids modulate norepinephrine (NE) signaling primarily via involvement of CB1 cannabinoid receptors (CB1r). Our previous studies have shown that acute and repeated administration of a CB1r agonist increases multiple indices of noradrenergic activity involving the locus coeruleus (LC)-frontal cortex (FC) pathway. Diacylglycerol lipase-α (DGL-α), a key enzyme in the biosynthesis of the endocannabinoid 2-arachidonoylglycerol (2-AG) is localized to both the FC and the LC. Using electron microscopy, we have recently shown that in the rat FC DGL-α is localized in postsynaptic profiles that are targeted by dopamine-β-hydroxylase (DβH), the enzyme that converts dopamine to norepinephrine and represents a marker of noradrenergic neurons (Hartman et al., 1972). In this study, we also described interactions between DGL-α, CB1r and DβH in the FC using confocal microscopy. In the present study, we investigated expression levels of DGL-α under two conditions of NE deletion: in a rat model using a systemic injection of saporin conjugated with antibody against DβH (DSP-4) and in a genetically engineered mouse that lacked the enzyme DβH (DβH-knockout, KO). We compared expression levels of DGL-α to either control rats or wild type (WT) mice using Western blot analysis. Protein extracts from micropunches of FC and LC were obtained and probed for DGL-α. Results showed that DGL-α expression was significantly increased in FC (P < 0.05) of both DSP-4 treated rats and DβHKO mice when compared to WT mice. DGL-α expression was also significantly increased in the LC (P < 0.05) of DβHKO when compared to WT mice. These data add to the accumulating evidence that dysregulation of NE transmission results in significant adaptations in the brain endocannabinoid system.

Related Products: Anti-DBH-SAP (Cat. #IT-03)

GABA-A receptor activity in the noradrenergic locus coeruleus drives trigeminal neuropathic pain in the rat; contribution of NAα1 receptors in the medial prefrontal cortex.

Kaushal R, Taylor B, Jamal A, Zhang L, Ma F, Donahue R, Westlund K (2016) GABA-A receptor activity in the noradrenergic locus coeruleus drives trigeminal neuropathic pain in the rat; contribution of NAα1 receptors in the medial prefrontal cortex. Neuroscience 334:148-159. doi: 10.1016/j.neuroscience.2016.08.005

Summary: The goal of this study was to investigate the role of the locus coeruleus (LC) in a rat orofacial pain model of trigeminal neuropathy induced by chronic constrictive injury of the infraorbital nerve (CCI-ION). Mechanical thresholds to von Frey filaments were tested on whisker pads to evaluate neuropathic pain behavior; pain was indicated by development of mechanical hypersensitivity. Noradrenergic (NA) neurons were lesioned with 5-mcg injections of Anti-DBH-SAP (Cat. #IT-03) into the left lateral ventricle. Mouse-IgG-SAP (Cat. #IT-18) was used as a control. After ablation of NA neurons there was a notable increase in the mechanical threshold compared to control animals. They also targeted coeruleotrigeminal NA neurons by injecting Anti-DBH-SAP into the trigeminal brainstem nuclei bilaterally in one animal and saw similar results. Injecting a GABAA receptor antagonist into the LC after injury had an inhibitory effect on nerve injury induced hypersensitivity. Injection of a NAα1 receptor antagonist, but not a NAα2 receptor antagonist, into the medial prefrontal cortex (mPFC) alleviates mechanical hypersensitivity. They conclude that GABAA-mediated activation of NA neurons during CCI-ION can facilitate hypersensitivity through NAα1 receptors in the mPFC, and that the LC is a chronic pain generator.

Related Products: Anti-DBH-SAP (Cat. #IT-03), Mouse IgG-SAP (Cat. #IT-18)

A2 noradrenergic neurons regulate forced swim test immobility.

Nam H, Kerman I (2016) A2 noradrenergic neurons regulate forced swim test immobility. Physiol Behav 165:339-349. doi: 10.1016/j.physbeh.2016.08.020

Summary: Wistar-Kyoto rats are often used as a model of depression, and exhibit high levels of immobility when subjected to a forced swim test (FST). Researchers discovered relative hyperactivation in the locus coeruleus of WKY rats compared to the genetically related Wistar rats when exposed to one- and two-day FSTs. Lesser activation of A2 noradrenergic cell group was seen by diminished levels of FOS after both days of the FST. A2 noradrenergic neurons of Winstar rats were lesioned by injecting 2.2 ug of Anti-DBH-SAP (Cat. #IT-03) into the nucleus tractus solitaris (NTS). Lesioned rats exhibited increased FST immobility on both days of the test, similar to natural WKY behavior in the same test. These data indicate that the A2 noradrenergic cell group regulates FST behavior and that its hypoactivation may contribute to the unique behavioral phenotype of WKY rats.

Related Products: Anti-DBH-SAP (Cat. #IT-03)

Differential roles for cortical versus sub-cortical noradrenaline and modulation of impulsivity in the rat.

Benn A, Robinson E (2017) Differential roles for cortical versus sub-cortical noradrenaline and modulation of impulsivity in the rat. Psychopharmacology (Berl) 234:255-266.. doi: 10.1007/s00213-016-4458-8

Summary: Atomoxetine is a noradrenaline re-uptake inhibitor licensed for the treatment of adult and childhood attention deficit hyperactivity disorder. Although atomoxetine has established efficacy, the mechanisms which mediate its effects are not well understood. In this study, the authors investigated the role of cortical versus sub-cortical noradrenaline by using focal dopamine beta hydroxylase-saporin-induced lesions, to the prefrontal cortex (PFC) or nucleus accumbens shell (NAcSh). Male Lister hooded rats received bilateral lesions by using stereotaxic injections of the immunotoxin Anti-DβH-SAP (Cat. #IT-03), 0.02 μg in 0.5 μL per injection into the PFC and 0.004 μg in 0.2 μL per injection for NAcSh lesions. The data suggest that noradrenaline in the nucleus accumbens shell plays an important role in the effects of atomoxetine. Under these conditions, prefrontal cortex noradrenaline did not appear to contribute to atomoxetine’s effects suggesting a lack of cortical-mediated “top-down” modulation. Noradrenaline in the prefrontal cortex appears to contribute to the modulation of impulsive responding in amphetamine-treated animals, with a loss of noradrenaline associated with potentiation of its effects. These data demonstrate a potential dissociation between cortical and sub-cortical noradrenergic mechanisms and impulse control in terms of the actions of atomoxetine and amphetamine.

Related Products: Anti-DBH-SAP (Cat. #IT-03)

Acute hypoxia activates hypothalamic paraventricular nucleus-projecting catecholaminergic neurons in the C1 region.

Silva T, Takakura A, Moreira T (2016) Acute hypoxia activates hypothalamic paraventricular nucleus-projecting catecholaminergic neurons in the C1 region. Exp Neurol 285:1-11. doi: 10.1016/j.expneurol.2016.08.016

Summary: Catecholaminergic C1 cells reside in the rostral and intermediate portions of the ventrolateral medulla (RVLM) and can be activated by hypoxia. These neurons regulate the hypothalamic pituitary axis via direct projections to the hypothalamic paraventricular nucleus (PVH) and regulate the autonomic nervous system via projections to sympathetic and parasympathetic preganglionic neurons. The present results suggest that catecholaminergic C1-PVH projection is hypoxia-sensitive and the pathway between these two important brain areas can be one more piece in the complex puzzle of neural control of autonomic regulation during hypoxia. Male Wistar rats were injected with the targeted toxin Anti-DβH-SAP (Cat. #IT-03), 21 ng/100 nl, or saline, unilaterally into the PVH using the following coordinates: 1.2 mm caudal to bregma, 0.4 mm lateral to the midline and 7.8 mm below the dura mater. The author’s work adds a piece in the complex puzzle of the physiological role of the C1 cells by showing that this catecholaminergic group of cells must be activated only in emergency situations such as acute hypoxia, producing autonomic, metabolic, and neuroendocrine responses designed to help the organism survive major acute physical stresses.

Related Products: Anti-DBH-SAP (Cat. #IT-03)

Selective noradrenaline depletion impairs working memory and hippocampal neurogenesis.

Coradazzi M, Gulino R, Fieramosca F, Falzacappa L, Riggi M, Leanza G (2016) Selective noradrenaline depletion impairs working memory and hippocampal neurogenesis. Neurobiol Aging 48:93-102. doi: 10.1016/j.neurobiolaging.2016.08.012

Summary: Neuronal loss in the locus coeruleus (LC) of Alzheimer’s patients is well known, but the contribution of LC-derived noradrenergic afferents to learning and memory function is unknown. To model noradrenergic neuron degeneration in the LC, rats were bilaterally injected directly into the LC with 0.2 ug of Anti-DBH-SAP (Cat. #IT-03). Lesioned and sham-lesioned animals were tested behaviorally and exhibited robust working memory deficits but lesioning did not affect reference memory. They concluded that ascending noradrenergic afferents might be involved in more complex aspects of working memory, possibly via newly generated progenitors in the hippocampus.

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Locus coeruleus noradrenergic innervation of the amygdala facilitates alerting-induced constriction of the rat tail artery.

Mohammed M, Kulasekara K, Ootsuka Y, Blessing W (2016) Locus coeruleus noradrenergic innervation of the amygdala facilitates alerting-induced constriction of the rat tail artery. Am J Physiol Regul Integr Comp Physiol 310:R1109-1119. doi: 10.1152/ajpregu.00058.2016

Summary: The researchers tested the hypothesis that release of noradrenaline within the amygdala is important for the occurrence of SCVARS (sympathetic cutaneous vasoconstrictor alerting responses). A long-shanked 5-μl glass micropipette calibrated in 100-nl steps, was filled with vehicle or Anti-DBH-SAP (Cat. #IT-03). Anti-DBH-SAP (5 μg in 250 nl) or vehicle was injected into the amygdala during ∼1 min, and the pipette was left in place for an additional The locus coeruleus has been implicated in many aspects of emotional arousal, so that functional inhibition of the extensive locus coeruleus-derived noradrenergic innervation of centers known to be important in emotional arousal, including the amygdala, is likely to contribute to the therapeutic actions of clonidine-like agents. The locus coeruleus also has major reciprocal connections with the orexin-synthesizing neurons in the hypothalamus, and rats with genetically lesioned orexin receptor neurons (alternatively, oen could lesion with Orexin-SAP, Cat. #IT-20) have reduced emotional arousal as reflected in reduced SCVAR responses to alerting stimuli.

Related Products: Anti-DBH-SAP (Cat. #IT-03), Orexin-B-SAP (Cat. #IT-20)

Limiting glucocorticoid secretion increases the anorexigenic property of Exendin-4.

Lee S, Diener K, Kaufman S, Krieger J, Pettersen K, Jejelava N, Arnold M, Watts A, Langhans W (2016) Limiting glucocorticoid secretion increases the anorexigenic property of Exendin-4. Mol Metab 5:552-565. doi: 10.1016/j.molmet.2016.04.008

Summary: Glucagon-like peptide-1 (GLP-1) analogs lower blood surgar levels and cause a loss of appetite. Exendin-4 (Ex-4) is a GLP-1 receptor agonist, and also increases glucocorticoid secretion. Several tests were conducted to determine if the released glucocorticoids interact with Ex-4’s anorexigneic effect. One method involved ablating hindbrain catecholaminergic neurons by stereotaxically injecting 42 ng of Anti-DBH-SAP (Cat. #IT-03) bilaterally into the paraventricular nucleus of the hypothalamus in rats. Animals were injected with equimolar concentrations of unconjugated Saporin (Cat. #PR-01) as a control. Anti-DBH-SAP lesions reduced the efficacy of Ex-4 to increase corticosterone secretion but increased the anorexigenic effect, indicating that Ex-4-dependent corticosterone secretion opposes Ex-4’s actions. Anti-DBH-SAP lesions increased Ex-4’s ability to reduce food intake and body weight.

Related Products: Anti-DBH-SAP (Cat. #IT-03), Saporin (Cat. #PR-01)

Locus coeruleus and tuberomammillary nuclei ablations attenuate hypocretin/orexin antagonist-mediated rem sleep.

Schwartz M, Nguyen A, Warrier D, Palmerston J, Thomas A, Morairty S, Neylan T, Kilduff T (2016) Locus coeruleus and tuberomammillary nuclei ablations attenuate hypocretin/orexin antagonist-mediated rem sleep. eNeuro 3:ENEURO.0018-0016.2016. doi: 10.1523/ENEURO.0018-16.2016

Summary: To examine the mechanism by which the Orexin 1r/Orexin 2r antagonist almorexant decreases wakefulness and increases NREM and REM sleep the authors utilized Anti-DBH-SAP (Cat. #IT-03) and Orexin-B-SAP (Cat. #IT-20). Rats received 3-μg injections of Anti-DBH-SAP into the LC, or bilateral 57-80 ng injections of Orexin-SAP into the TMN. Both conjugates attenuated the increased REM sleep seen upon administration of almorexant without altering almorexant-induced changes in NREM sleep.

Related Products: Anti-DBH-SAP (Cat. #IT-03), Orexin-B-SAP (Cat. #IT-20)

Disruption of spinal noradrenergic activation delays recovery of acute incision-induced hypersensitivity and increases spinal glial activation in the rat.

Arora V, Morado-Urbina C, Aschenbrenner C, Hayashida K, Wang F, Martin T, Eisenach J, Peters C (2016) Disruption of spinal noradrenergic activation delays recovery of acute incision-induced hypersensitivity and increases spinal glial activation in the rat. J Pain 17:190-202. doi: 10.1016/j.jpain.2015.10.009

Summary: A significant percentage of patients who undergo surgery experience prolonged clinically impactful pain, reducing the quality of life and physical function. Disruption of the descending noradrenergic input has been hypothesized to be important to the generation of this type of pain state. Using an acute incision model, the authors administered 5 μg ofAnti-DBH-SAP (Cat. #IT-03) to the L5-L6 interspace of rats. Mouse IgG-SAP (Cat. #IT-18) was used as a control. Lesioned animals demonstrated a significant increase in mechanical hypersensitivity, and a smaller increase in thermal hypersensitivity. This and other results suggest that spinally projecting noradrenergic pathways are necessary for normal recovery from surgical incision, and possibly other types of pain.

Related Products: Anti-DBH-SAP (Cat. #IT-03), Mouse IgG-SAP (Cat. #IT-18)

Catecholaminergic neurons in the comissural region of the nucleus of the solitary tract modulate hyperosmolality-induced responses.

Freiria-Oliveira A, Blanch G, Pedrino G, Cravo S, Murphy D, Menani J, Colombari D (2015) Catecholaminergic neurons in the comissural region of the nucleus of the solitary tract modulate hyperosmolality-induced responses. Am J Physiol Regul Integr Comp Physiol 309:R1082-1091. doi: 10.1152/ajpregu.00432.2014

Summary: Body fluid homeostasis and cardiovascular regulation are thought to be at least in part controlled by noradrenergic A2 neurons found in the nucleus of the solitary tract (NTS). In this work the authors investigated the involvement of A2 neurons of the commissural NTS in arterial pressure, as well as several body fluid homeostasis parameters. Rats received 12.6-ng injections of Anti-DBH-SAP (Cat. #IT-03) into the commissural NTS. Mouse IgG-SAP (Cat. #IT-18) was used as a control. Lesioned animals displayed increased c-Fos expression in the hypothalamic paraventricular nucleus when treated with hypertonic NaCl, and increased arterial pressure. The data indicate that commissural NTS A2 neurons are essential for inhibitory mechanisms that reduce water intake and pressor response to an acute increase in plasma osmolality.

Related Products: Anti-DBH-SAP (Cat. #IT-03), Mouse IgG-SAP (Cat. #IT-18)

A2 noradrenergic neurons regulate forced swim test immobility

Nam H, Kerman I (2015) A2 noradrenergic neurons regulate forced swim test immobility. Neuroscience 2015 Abstracts 718.10/Y20. Society for Neuroscience, Chicago IL.

Summary: The Wistar-Kyoto rat (WKY) is a well-established animal model of depression- and anxiety-like behavior, characterized by high immobility during the forced swim test (FST) along with a generally inhibited phenotype on related tests of emotional behaviors. Extensive literature indicates that deficits in noradrenergic neurotransmission may contribute to these behavioral traits. Previously, we have reported that the WKY rats are more immobile compared to other rat strains from the beginning of their training phase of the FST, and that they become even more immobile during the testing phase on the next day. We hypothesized that higher immobility during the FST and the greater increase in immobility throughout different phases of the FST are two separate components of rats’ behavior likely mediated by different central mechanisms. We sought to identify the central circuits responsible for these behavioral components by studying activation of neurons within central noradrenergic cell groups during different phases of the FST. The WKY rats along with its parent strain, Wistar rats that experienced either the: 1) 5 minutes training phase (D1), or 2) entire FST (D1 and D2) were compared. Using double-immunocytochemistry for tyrosine hydroxylase and for c-Fos, we determined that within the A2 cell group significantly more noradrenergic neurons were activated in the Wistar than in WKY rats at D1. At D2 WKYs increased their activation of the A2 noradrenergic neurons, and this activation was equivalent to that of the Wistar group. Based on these results, we further investigated the role of A2 cell group during the FST using anti-DBH conjugated saporin (DSAP) to selectively destroy noradrenergic neurons within the area. The Wistar rats treated with DSAP were more immobile during both D1 and D2 of the FST as compared to the rats treated with the vehicle only. Together these data indicate that the A2 noradrenergic cell group regulates FST immobility in rats, and that its activation may contribute to the unique behavioral phenotype of WKY rats. Future experiments aimed at selective activation of A2 noradrenergic neurons will be required to fully elucidate the role of these neurons in mediating behavioral despair and learned helplessness.

Related Products: Anti-DBH-SAP (Cat. #IT-03)

Astrocytic lesions that spare neurons in the nucleus tractus solitarii interfere with cardiorespiratory control

Richerson GB, Dragon DN, Jones S, Wu Y, Talman WT (2015) Astrocytic lesions that spare neurons in the nucleus tractus solitarii interfere with cardiorespiratory control. Neuroscience 2015 Abstracts 297.15/B100. Society for Neuroscience, Chicago IL.

Summary: Conjugates of saporin (SAP) have been widely used to target specific neurons while leaving other neurons undisturbed. We found that killing catecholamine neurons bilaterally in the nucleus tractus solitarii (NTS) by injection of the SAP conjugate containing an antibody to dopamine-_-hydroxylase (anti-DBH-SAP) spared non-catecholamine neurons but led to attenuation of baroreceptor reflexes, lability of arterial pressure, and, in some animals, sudden death. In contrast, selective targeting of catecholamine neurons with 6-hydroxydopamine produced no such cardiovascular events. We hypothesized that SAP conjugates may target non-neuronal cells in the NTS. Indeed, we found that local astrocytes were killed by the conjugates as well as by unconjugated SAP itself. SAP injections into the NTS led to death of astrocytes that expressed glial fibrillary acidic protein (GFAP) but did not affect neuronal structural markers and neuronal biosynthetic enzymes. Our recent studies further suggest that local neurons are physiologically intact. Nonetheless, SAP injections into the NTS significantly reduced cardiovascular responses elicited by glutamate agonists injected into the NTS, and bilateral injections of SAP into the NTS led to attenuation of cardiovascular reflexes whose pathways pass through the NTS, lability of arterial pressure, damage to cardiac myocytes and sudden death resulting from asystole. When asystole and death followed SAP treatment the fatal arrhythmia followed progressive bradycardia. In that treated animals demonstrate altered ventilatory function, we conjecture that it is altered ventilation that leads to cardiac compromise and death.

Related Products: Anti-DBH-SAP (Cat. #IT-03)

Direct impact of dopaminergic and noradrenergic systems on adult-hippocampal neurogenesis in adult rats and the relevance to dementia in Parkinson’s disease

Ermine C, Wright JL, Parish CL, Thompson LH (2015) Direct impact of dopaminergic and noradrenergic systems on adult-hippocampal neurogenesis in adult rats and the relevance to dementia in Parkinson’s disease. Neuroscience 2015 Abstracts 217.06/C66. Society for Neuroscience, Chicago IL.

Summary: A key pathological feature of Parkinson’s disease (PD) is the progressive degeneration of midbrain dopaminergic neurons, causing motor dysfunction. However there are a range of ‘non-movement’ related features (including cognitive dysfunction, dementia and sleep disorder), which are not alleviated by dopamine replacement therapy. We are currently investigating the hypothesis that reduced hippocampal neurogenesis contributes to cognitive dysfunction in PD. We aim to characterise the effect of the dopaminergic and noradrenergic system on the adult-hippocampal neurogenesis in order to identify potential targets for the treatment cognitive impairments related to neurogenesis. We induced lesions of the different systems in adult rats using stereotaxic injections of toxins: 6-hydroxydopamine (dopaminergic system) and anti-dopa-β-hydroxylase-saporin (noradrenergic system). Four weeks later, the new cells were marked by pulses of bromodeoxyuridine (Brd-U) twice daily for 1 week. The animals were then sacrificed 4 weeks later for tissue collection. A high-performance liquid chromatography has confirmed that both lesions were successful: dopamine level in the striatum dropped to 20% and noradrenaline level in the hippocampus dropped to 8.3%. Surprisingly there was no difference in the number of Brd-U positive cells or in the number of double positive Brd-U/NeuN cells between our groups. The results show that while both noradrenergic and dopaminergic systems are implicated in the onsets of non-motor symptoms, they may not act through the regulation of adult-hippocampal neurogenesis like it was previously thought. Importantly our project has allowed reconsideration of how neurogenesis is involved in PD and redirected the therapies to better potential targets for treatment.

Related Products: Anti-DBH-SAP (Cat. #IT-03)

Selective inhibition of dopamine-beta-hydroxylase enhances dopamine release from noradrenergic terminals in the medial prefrontal cortex.

Devoto P, Flore G, Saba P, Frau R, Gessa G (2015) Selective inhibition of dopamine-beta-hydroxylase enhances dopamine release from noradrenergic terminals in the medial prefrontal cortex. Brain Behav 5:e00393. doi: 10.1002/brb3.393

Summary: Dopamine-beta-hydroxylase (DBH) is a neuronal enzyme that is a potential target for the treatment of cocaine abuse, alcohol dependence, and eating disorders. Here the authors administered 5 μg of icv Anti-DBH-SAP (Cat. #IT-03) to rats, and assessed the effect of the dopaminergic lesion on levels of extracellular dopamine. Mouse IgG-SAP (Cat. #IT-18) and saporin (Cat. #PR-01) were used as controls. Extracellular levels of dopamine were significantly increased in both lesioned animals and those treated with the DBH inhibitor nepicastat. Clonadine could reverse the nepicastat effect, but not the effect of Anti-DBH-SAP treatement. The data demonstrate a mechanism for the synergistic effect of cocaine on nepicastat-induced dopamine release.

Related Products: Anti-DBH-SAP (Cat. #IT-03), Mouse IgG-SAP (Cat. #IT-18), Saporin (Cat. #PR-01)

Orexin-A enhances feeding in male rats by activating hindbrain catecholamine neurons.

Li A, Wang Q, Davis H, Wang R, Ritter S (2015) Orexin-A enhances feeding in male rats by activating hindbrain catecholamine neurons. Am J Physiol Regul Integr Comp Physiol 309:R358-367. doi: 10.1152/ajpregu.00065.2015

Summary: Although administration of orexin, norepinephrine, and epinephrine all induce significantly increased food intake, the potential interaction between the networks affected by these molecules has not been studied. In this work, the authors investigate the hypothesis that orexin neurons may stimulate feeding through the activation of catecholamine neurons. Rats received 82-ng injections of Anti-DBH-SAP (Cat. #IT-03) into the hypothalamus in order to lesion hypothalamically-projecting catecholamine neurons. Saporin (Cat. #PR-01) was used as a control. While the normal response to orexin A is increased food intake, lesioned animals did not display this response, indicating that catecholamine neurons are necessary for orexin modulation of food intake.

Related Products: Anti-DBH-SAP (Cat. #IT-03), Saporin (Cat. #PR-01)

Catecholaminergic neurons projecting to the paraventricular nucleus of the hypothalamus are essential for cardiorespiratory adjustments to hypoxia.

King T, Ruyle B, Kline D, Heesch C, Hasser E (2015) Catecholaminergic neurons projecting to the paraventricular nucleus of the hypothalamus are essential for cardiorespiratory adjustments to hypoxia. Am J Physiol Regul Integr Comp Physiol 309:R721-731. doi: 10.1152/ajpregu.00540.2014

Summary: Catecholaminergic neurons in the brainstem are known to be involved in cardiorespiratory control and to modulate sensory function. Some of the projections from these neurons are to the paraventricular nucleus (PVN), and are involved in cardiorespiratory and neuroendocrine responses to hypoxia. While data have shown the PVN-projecting neurons are activated by hypoxia, their function in this context is not known. In this work the authors bilaterally injected 42 ng of Anti-DBH-SAP (Cat. #IT-03) into the PVN of rats. Mouse IgG-SAP (Cat. #IT-18) was used as control. Respiratory measurements of the lesioned animals indicates that PVN-projecting catecholaminergic neurons are involved in peripheral and central chemoreflex and arterial oxygen levels during exposure to hypoxic stimuli.

Related Products: Anti-DBH-SAP (Cat. #IT-03), Mouse IgG-SAP (Cat. #IT-18)

Selective C1 lesioning slightly decreases angiotensin II type I receptor expression in the rat rostral ventrolateral medulla (RVLM).

Bourassa E, Stedenfeld K, Sved A, Speth R (2015) Selective C1 lesioning slightly decreases angiotensin II type I receptor expression in the rat rostral ventrolateral medulla (RVLM). Neurochem Res 40:2113-2120. doi: 10.1007/s11064-015-1649-3

Summary: Exogenous angiotensin II administered to the RVLM produces a significant pressor response that can be countered by angiotensin II type I receptor antagonists. In this work the authors examined the relative contribution of C1 and non-C1 neurons in the RVLM to this angiotensin II response. Rats received 10 or 15 ng of Anti-DBH-SAP (Cat. #IT-03) as unilateral injections into the RVLM. Mouse IgG-SAP (Cat. #IT-18) was used as control. The data indicate that the majority of angiotensin II type 1 receptors are expressed on non-C1 neurons or glia.

Related Products: Anti-DBH-SAP (Cat. #IT-03), Mouse IgG-SAP (Cat. #IT-18)

Selective optogenetic stimulation of the retrotrapezoid nucleus in sleeping rats activates breathing without changing blood pressure or causing arousal or sighs.

Burke P, Kanbar R, Viar K, Stornetta R, Guyenet P (2015) Selective optogenetic stimulation of the retrotrapezoid nucleus in sleeping rats activates breathing without changing blood pressure or causing arousal or sighs. J Appl Physiol (1985) 118:1491-1501. doi: 10.1152/japplphysiol.00164.2015

Summary: Hypoxia and hypercapnia both play roles in the activation of normal breathing. If either one is severe enough, arousal will also occur. The authors looked to better define the CNS pathways utilized by hypoxia and hypercapnia, as well as the pathways responsible for activation of arousal due to these conditions. The authors used optogenetic activation of the retrotrapezoid nucleus and C1 and A5 catecholaminergic neurons, as well as selective C1 neuron stimulation in rats. Some rats also received bilateral injections of Anti-DBH-SAP (Cat. #IT-03) totaling 0.88 μg into the region of the lateral horn of the second thoracic segment.

Related Products: Anti-DBH-SAP (Cat. #IT-03)

Hindbrain catecholamine neurons activate orexin neurons during systemic glucoprivation in male rats.

Li A, Wang Q, Elsarelli M, Brown R, Ritter S (2015) Hindbrain catecholamine neurons activate orexin neurons during systemic glucoprivation in male rats. Endocrinology 156:2807-2820. doi: 10.1210/en.2015-1138

Summary: Norepinephrine and epinephrine-secreting catecholamine neurons are strong stimulators of food intake. The authors investigated the interaction between these catecholamine neurons and orexin neurons in the perifornical lateral hypothalamus (PeFLH), which are known to be involved with the stimulation of food intake, increased arousal, and behavioral activation. Rats received 82-ng injections of Anti-DBH-SAP (Cat. #IT-03) into the PeFLH terminal field in order to lesion catecholamine neurons. Saporin (Cat. #PR-01) was used as a control. Assessment of food intake in response to 2-deoxy-D-glucose, as well as selective catecholamine activation, indicated that orexin neuron activation may be involved in glucoprivic appetite responses.

Related Products: Anti-DBH-SAP (Cat. #IT-03), Saporin (Cat. #PR-01)

Individual differences in acute pain-induced endogenous analgesia predict time to resolution of postoperative pain in the rat.

Peters C, Hayashida K, Suto T, Houle T, Aschenbrenner C, Martin T, Eisenach J (2015) Individual differences in acute pain-induced endogenous analgesia predict time to resolution of postoperative pain in the rat. Anesthesiology 122:895-907. doi: 10.1097/ALN.0000000000000593

Summary: The authors investigated the relationship between preoperative Conditioned Pain Modulation (CPM) and the time course of recovery from surgery. CPM was evaluated using forepaw capsaicin injections into rats. During the study, lesioned rats received 5-μg intrathecal injections of anti-DBH-SAP (Cat. #IT-03), followed 14 days later by a partial L5 spinal nerve ligation surgery. Mouse-IgG-SAP (Cat. #IT-18) was used as a control. CPM was partially blocked in the lesioned animals, suggesting descending noradrenergic signaling is important in the time course of recovery from surgery.

Related Products: Anti-DBH-SAP (Cat. #IT-03), Mouse IgG-SAP (Cat. #IT-18)

Contribution of hindbrain catecholamine neurons to orexin-induced feeding

Li A-J, Wang Q, Davis H, Ritter S (2014) Contribution of hindbrain catecholamine neurons to orexin-induced feeding. Neuroscience 2014 Abstracts 834.08. Society for Neuroscience, Washington, DC.

Summary: Both lateral hypothalamic orexinergic neurons and hindbrain catecholaminergic neurons contribute to feeding behavior. In addition, both phenotypes are widely distributed in the brain and their terminal sites are in many cases overlapping. In the hindbrain, both orexin receptor subtypes (OX1R and OX2R) have been found in close proximity to dopamine-β-hydroxylase (DBH)-expressing cell bodies, raising the question of whether orexin stimulates feeding by activating catecholamine neurons. We tested this hypothesis in the present study. First, we implanted rats with fourth ventricular (4V) cannulas and tested feeding in response to 4V injection of orexin (0.5 nmol). Orexin stimulated feeding in rats, and this stimulation was abolished in rats given paraventricular hypothalamic injections of the retrogradely-transported immunotoxin, anti-DBH-saporin, which targets and destroys DBH-expressing neurons. We then examined hindbrain c-Fos expression in normal rats in response to 4V injection of the same orexin dose that stimulated food intake. Using multiple immunofluorescent labels and confocal microscopy we found that most of the orexin-induced c-Fos-immunoreactive (-ir) neurons in the dorsomedial and ventrolateral medulla were DBH-ir and, moreover, that orexin-ir varicosities were situated in close proximity to the Fos-expressing DBH-ir soma. Together these results suggest that orexin stimulates feeding, at least in part, by activating hindbrain catecholamine neurons.

Related Products: Anti-DBH-SAP (Cat. #IT-03)

Hindbrain catecholaminergic projections to the paraventricular nucleus are required for activation of glutamatergic terminals by glycemic challenges

Johnson CS, Watts AG (2014) Hindbrain catecholaminergic projections to the paraventricular nucleus are required for activation of glutamatergic terminals by glycemic challenges. Neuroscience 2014 Abstracts 452.13. Society for Neuroscience, Washington, DC.

Summary: Hindbrain catecholaminergic inputs to the paraventricular nucleus of the hypothalamus (PVH) are necessary for the full response of neuroendocrine neurons to glycemic challenges. The drive provided to the neuroendocrine neurons by ascending catecholaminergic afferents also appears to require a glutamatergic component, as direct norepinephrine stimulation of the peri-PVH region results in a significant increase in glutamatergic excitatory postsynaptic potentials. To determine if these hindbrain catecholaminergic afferents are required to increase the excitatory synaptic drive to neuroendocrine neurons in the medial parvocellular region (mp) of the PVH, we have developed an immunocytochemical (ICC) method to assess if appositions alter their activity in response to a stimulus. This method relies on detecting the increased phosphorylation states of two key intracellular signaling intermediaries, ERK and synapsin I (Syn I), that occur as terminals become activated. Adult male Sprague-Dawley rats received central injections of the immunotoxin saporin conjugated with a dopamine-β-hydroxylase antibody, aimed at the PVH, to ablate catecholaminergic projections from the hindbrain. Rats were then fitted with jugular catheters and administered 2U/kg/ml insulin or 250 mg/kg 2-deoxy-glucose. Following perfusion, coronal sections were cut through the PVH and run for ICC using antibodies against Vesicular Glutamate Transporter 2 (VGluT2), phospho-ERK, and phospho-Syn I. Confocal Z-stacked images through the PVH were acquired, and analysis of 3D images was performed using Volocity software to assess colocalization of VGluT2 with phospho-ERK & phospho-Syn I in terminals within the PVHmp. The mean Pearson’s Colocalization Coefficient was compared across groups. With a glycemic challenge, animals with intact catecholaminergic projections showed an increased numbers of appositions exhibiting colocalization of VGluT2 with the phosphorylated signaling molecules compared to controls. Animals without hindbrain catecholaminergic projections, however, had significantly fewer colocalized appositions. This suggests that catecholaminergic inputs from the hindbrain to the PVH are necessary for the glutamatergic excitation to the neuroendocrine neurons in the medial parvocellular region of the PVH in response to a glycemic stressor, as demonstrated through changes in appositional activity levels.

Related Products: Anti-DBH-SAP (Cat. #IT-03)

C1 neurons excite A5 noradrenergic neurons during hypoxia condition

Borella TL, Takakura AC, Moreira TS (2014) C1 neurons excite A5 noradrenergic neurons during hypoxia condition. Neuroscience 2014 Abstracts 168.07. Society for Neuroscience, Washington, DC.

Summary: C1 neurons activate sympathetic tone and stimulate the hypothalamic-pituitary-adrenal axis in circumstances such as pain, hypoxia or hypotension. They also innervate pontine noradrenergic cells group, including the locus coeruleus (LC) and the ventrolateral pontine catecholaminergic region (A5). Activation of C1 neurons reportedly inhibits pontine neurons; however, because these neurons are glutamatergic and have excitatory effects elsewhere, we re-examined the effect of C1 activation on pontine noradrenergic neurons (A5) using a more selective method. We examined the neuronal effects of destroying C1 catecholaminergic neurons with unilateral injection of the immunotoxin anti-dopamine beta-hydroxylase-saporin (anti-DβH-Sap) into the A5 region during hypoxic condition. Bilateral injections of anti-DβH-Sap into A5 destroyed tyrosine hydroxylase (TH) neurons but spared facial motoneurons and serotonergic neurons within the ventrolateral medulla. Hypoxia (8% O2 - 3 hours) induced a robust increase in Fos expression within the catecholaminergic C1 region of the ventrolateral medulla. On the lesioned side, Fos expression was significantly reduced (53.4 ± 17.6 vs. control: 129.8 ± 22.3 neurons) within the C1 region after hypoxia challenge. Residual Fos expression seen in lesioned side in response to hypoxia provides a basis for probing additional circuits that may be recruited in hierarchical manner in response to hypoxia. In conclusion, the C1 neurons activate the ventrolateral pontine noradrenergic neurons (A5 region) possibly via the release of glutamate from monosynaptic C1 inputs.

Related Products: Anti-DBH-SAP (Cat. #IT-03)

Lesions of hindbrain catecholaminergic projections to nucleus accumbens, bed nucleus of the stria terminalis, lateral parabrachial nucleus or locus coeruleus do not impair glucoprivic feeding

Dinh TT, Huston N, Ritter S (2014) Lesions of hindbrain catecholaminergic projections to nucleus accumbens, bed nucleus of the stria terminalis, lateral parabrachial nucleus or locus coeruleus do not impair glucoprivic feeding. Neuroscience 2014 Abstracts 256.05. Society for Neuroscience, Washington, DC.

Summary: We have shown previously that injection of the retrogradely transported immunotoxin, anti-dopamine beta-hydroxylase (DBH) saporin (DSAP), into the paraventricular nucleus of the hypothalamus (PVH) or arcuate nucleus, abolishes feeding in response to central or systemic glucoprivation. Since DSAP injection destroys DBH-expressing neurons with projections to the injection site, these results strongly implicate hindbrain catecholamine neurons as major mediators of glucoprivic feeding. In order to further define the essential circuitry underlying glucoprivic feeding, we injected DSAP into these additional sites: locus coeruleus (LC), accumbens shell (AcbSh), ventrolatersal bed nucleus of the stria terminalis (vlBNST) and lateral parabrachial nucleus (LPBN). These sites are innervated by hindbrain catecholamine neurons and some sites receive collateral innervation from PVH-projecting catecholamine neurons. Appropriate placement and volume for DSAP administration was determined by co-labeling of DBH-ir neurons with retrograde tracer injected into target sites. Lesions were confirmed by postmortem evaluation of DSAP injection site and by hindbrain catecholamine cell and terminal loss. We found that the feeding response to systemic glucoprivation was not significantly or permanently impaired by injection of DSAP into any of these sites. Based on our results to date, we tentatively conclude that direct projections from hindbrain catecholamine neurons to the LC, AcbSh, vlBNST and LPBN are not required for glucoprivic feeding. The hypothalamus appears to be the major recipient of direct innervation from catecholamine neurons required for glucoprivic feeding

Related Products: Anti-DBH-SAP (Cat. #IT-03)

Effects of noradrenergic denervation by anti-DBH-saporin on behavioral responsivity to L-DOPA in the hemi-parkinsonian rat.

Ostock C, Lindenbach D, Goldenberg A, Kampton E, Bishop C (2014) Effects of noradrenergic denervation by anti-DBH-saporin on behavioral responsivity to L-DOPA in the hemi-parkinsonian rat. Behav Brain Res 270:75-85. doi: 10.1016/j.bbr.2014.05.009

Summary: Dopamine loss is central to Parkinson's disease and is often accompanied by noradrenergic denervation of the locus coeruleus. In this work the authors examined the role this loss plays in L-DOPA therapy using a rat Parkinson's disease model. The rats received 10 μg of anti-DBH-SAP (Cat. #IT-03) into the left lateral ventricle. Loss of norepinephrine (NE) neurons did not affect behavior, but lesioned animals were less responsive to the pro-motor therapeutic effects of L-DOPA.

Related Products: Anti-DBH-SAP (Cat. #IT-03)

Role of paraventricular nucleus-projecting norepinephrine/epinephrine neurons in acute and chronic stress.

Flak J, Myers B, Solomon M, McKlveen J, Krause E, Herman J (2014) Role of paraventricular nucleus-projecting norepinephrine/epinephrine neurons in acute and chronic stress. Eur J Neurosci 39:1903-1911. doi: 10.1111/ejn.12587

Summary: Chronic stress can cause dysregulation of the paraventricular nucleus (PVN) of the hypothalamus, resulting in structural and function changes in the neurons involved. There are data indicating that post-stress enhancement of norepinephrine is involved in the processing of chronic stress. In this work the authors investigated the hypothesis that PVN-projecting norepinephrine/epinephrine (NE/E) neurons are necessary for chronic stress-induced drive of the hypothalamic-pituitary-adrenocortical (HPA) axis. Rats received bilateral 8.82 ng injections of anti-DBH-SAP (Cat. #IT-03) into the PVN. Saporin (Cat. #PR-01) was used as a control. Lesioned animals displayed attenuated peak ACTH, indicating that NE/E neurons are required for ACTH release in the HPA axis during chronic stress.

Related Products: Anti-DBH-SAP (Cat. #IT-03), Saporin (Cat. #PR-01)

Noradrenaline neuron degeneration contributes to motor impairments and development of L-DOPA-induced dyskinesia in a rat model of Parkinson’s disease.

Shin E, Rogers J, Devoto P, Björklund A, Carta M (2014) Noradrenaline neuron degeneration contributes to motor impairments and development of L-DOPA-induced dyskinesia in a rat model of Parkinson's disease. Exp Neurol 257:25-38. doi: 10.1016/j.expneurol.2014.04.011

Summary: Although Parkinson's disease is usually associated with loss of dopaminergic neurons in the substantia nigra, post-mortem studies have shown that noradrenergic neurons in the locus coeruleus also degenerate. In this work the authors develop a new Parkinson's disease model by double lesioning with both 6-OHDA into the striatum and 2.5 μg bilateral injections of anti-DBH-SAP (Cat. #IT-03) into the lateral ventricles of rats. Double-lesioned animals performed worse on tests evaluating Parkinson's disease symptoms than those lesioned only with 6-OHDA. The data suggest that Parkinson's disease symptoms reflect the loss of both dopaminergic and noradrenergic neurons in the midbrain.

Related Products: Anti-DBH-SAP (Cat. #IT-03)

The rate of fall of blood glucose determines the necessity of forebrain-projecting catecholaminergic neurons for male rat sympathoadrenal responses.

Jokiaho A, Donovan C, Watts A (2014) The rate of fall of blood glucose determines the necessity of forebrain-projecting catecholaminergic neurons for male rat sympathoadrenal responses. Diabetes 63:2854-2865. doi: 10.2337/db13-1753

Summary: Different sets of glucosensors detect insulin-induced hypoglycemia depending on the onset rate. This detection controls the activation of sympathoadrenal counterregulatory responses (CRRs). Slow onset hypoglycemia, common with insulin therapy, is detected by glucosensors in the portal-mesenteric veins. Fast onset is detected by brain elements. The authors lesioned hindbrain catecholaminergic neurons to determine which set of responses-they interact with. Rats received 42 ng bilateral injections of Anti-DBH-SAP (Cat. #IT-03) into the paraventricular nucleus of the hypothalamus. Mouse IgG-SAP (Cat. #IT-18) was used as a control. The data indicate that these neurons are critical for detection of slow-onset insulin-induced hypoglycemia.

Related Products: Anti-DBH-SAP (Cat. #IT-03), Mouse IgG-SAP (Cat. #IT-18)

Stimulation of feeding by three different glucose-sensing mechanisms requires hindbrain catecholamine neurons.

Li AJ, Wang Q, Dinh TT, Powers BR, Ritter S (2014) Stimulation of feeding by three different glucose-sensing mechanisms requires hindbrain catecholamine neurons. Am J Physiol Regul Integr Comp Physiol 306(4):R257-R264. doi: 10.1152/ajpregu.00451.2013

Summary: The glucoregulatory system of the brain requires catecholamine neurons in the hindbrain. he sensory mechanisms and connected circuitry controlling the response to glucose deficit are not well understood. In order to investigate different drugs that stimulate food intake but interfere with cellular glucose metabolism and transport the authors administered 82 ng of anti-DBH-SAP (Cat. #IT-03) into the paraventricular nucleus as bilateral injections. Saporin (Cat. #PR-01) was used as a control. Lesioned animals did not increase food intake in response to any of the drugs, indicating that stimulation of food intake is activated through a catecholamine-dependent pathway.

Related Products: Anti-DBH-SAP (Cat. #IT-03), Saporin (Cat. #PR-01)

Gabapentin increases extracellular glutamatergic level in the locus coeruleus via astroglial glutamate transporter-dependent mechanisms.

Suto T, Severino AL, Eisenach JC, Hayashida KI (2014) Gabapentin increases extracellular glutamatergic level in the locus coeruleus via astroglial glutamate transporter-dependent mechanisms. Neuropharmacology 81C:95-100. doi: 10.1016/j.neuropharm.2014.01.040

Summary: Gabapentin is effective in reducing acute and chronic pain, but the mechanisms by which it works are not well understood. The authors assessed extracellular glutamate levels and glutamate interaction with several different cellular membrane proteins. Rats received a 0.25 μg injection of anti-DBH-SAP (Cat. #IT-03) into the locus coeruleus (LC) in order to deplete noradreline levels. Mouse IgG-SAP (Cat. #IT-18) was used as a control. The gabapentin-induced glutamate increase in the LC was not affected by the lesion, supporting data indicating that gabapentin induces glutamate release from astrocytes to stimulate descending inhibition.

Related Products: Anti-DBH-SAP (Cat. #IT-03), Mouse IgG-SAP (Cat. #IT-18)

Lesion of the commissural nucleus of the solitary tract/A2 noradrenergic neurons facilitates the activation of angiotensinergic mechanisms in response to hemorrhage.

Freiria-Oliveira AH, Blanch GT, De Paula PM, Menani JV, Colombari DS (2013) Lesion of the commissural nucleus of the solitary tract/A2 noradrenergic neurons facilitates the activation of angiotensinergic mechanisms in response to hemorrhage. Neuroscience 254:196-204. doi: 10.1016/j.neuroscience.2013.09.017

Summary: Previous work has generated conflicting data on the role of catecholaminergic A2 neurons in the nucleus of the solitary tract (NTS) in control of arterial pressure lability. The authors used Anti-DBH-SAP (Cat. #IT-03) to lesion these neurons in a hypotensive hemorrhage model. Rats received two injections of 12.6 ng into the commissural NTS. Mouse IgG-SAP (Cat. #IT-18) was used as a control. The lesioned animals quickly recovered from hypotension, but were impaired by the icv administration of losartan.

Related Products: Anti-DBH-SAP (Cat. #IT-03), Mouse IgG-SAP (Cat. #IT-18)

C1 neurons: the body’s EMTs.

Guyenet PG, Stornetta RL, Bochorishvili G, Depuy SD, Burke PG, Abbott SB (2013) C1 neurons: the body’s EMTs. Am J Physiol Regul Integr Comp Physiol 305(3):R187-204 . doi: 10.1152/ajpregu.00054.2013

Summary: Although mainly known for their involvement in the control of arterial pressure, C1 neurons are also suspected to participate in numerous other physiological processes such as neuroendocrine response, glucose homeostasis, food consumption, and others. This review discusses the role of these neurons as 'emergency medical technicians' – cells that produce and modulate physiological survival responses to acute physical stress. The use of Anti-DBH-SAP (Cat. #IT-03) to delineate C1 neurons in the rostral ventrolateral aspect of the medulla oblongata is discussed.

Related Products: Anti-DBH-SAP (Cat. #IT-03)

Hindbrain noradrenergic input to the hypothalamic PVN mediates the activation of oxytocinergic neurons induced by the satiety factor oleoylethanolamide.

Romano A, Potes CS, Tempesta B, Cassano T, Cuomo V, Lutz T, Gaetani S (2013) Hindbrain noradrenergic input to the hypothalamic PVN mediates the activation of oxytocinergic neurons induced by the satiety factor oleoylethanolamide. Am J Physiol Endocrinol Metab 305(10):E1266-73. doi: 10.1152/ajpendo.00411.2013

Summary: Feeding behavior and energy balance are in part controlled by signals from the gut. Oleoylethanolamide (OEA) is an acylethanolamide that is thought to play a role in this network. Since peripheral administration of OEA has effects on the nucleus of the solitary tract (NTS) and paraventricular nucleus (PVN) the authors investigated the role of noradrenergic afferent input to these areas. Rats received bilateral 84-ng injections of Anti-DBH-SAP (Cat. #IT-03) into the PVN. Mouse IgG-SAP (Cat. #IT-18) was used as a control.

Related Products: Anti-DBH-SAP (Cat. #IT-03), Mouse IgG-SAP (Cat. #IT-18)

Compensatory feeding after reversing dehydration-anorexia: Is it analogous to glucoprivic or food deprivation-induced feeding?

Vargas SL, Watts AG (2013) Compensatory feeding after reversing dehydration-anorexia: Is it analogous to glucoprivic or food deprivation-induced feeding?. Neuroscience 2013 Abstracts 757.04. Society for Neuroscience, San Diego, CA.

Summary: We use dehydration (DE)-anorexia to identify the neural networks associated with feeding behavior. How these networks are organized and interact to control ingestive behavior in both the normal and anorexic states allows us to determine how they function in health and disease. DE-anorexia involves replacing drinking water with hypertonic saline (HS) for up to 5 days. This leads to cellular dehydration, and a reduction in food and body weight. Reversing DE-anorexia by removing HS and reinstating drinking water leads to a robust feeding episode. Here we used two experiments to determine whether this water-activated compensatory feeding is functionally related to 2-deoxyglucose (2DG)-activated (glucoprivic) or to food deprivation-induced feeding. First, we determined whether forebrain-projection catecholamine (CA) neurons in the hindbrain are required for water-activated compensatory feeding. These neurons project to the paraventricular nucleus of the hypothalamus (PVH) and are required for 2DG feeding. To do this we lesioned this pathway with the retrogradely-transported immunotoxin, anti-dopamine beta-hydroxylase (DBH) Saporin (DSAP). Anesthetized adult male Sprague-Dawley rats (300g) were injected into the PVH with either a control SAP (MIgSAP) or DSAP. Three weeks later animals were housed in BioDaq monitoring cages to record their feeding behavior. All animals were given HS for 5 days. They were then given drinking water back on the 5th day, and euthanized 75 minutes later. Lack of immunohistochemical staining (IHC) for DBH in the PVH confirmed complete lesions. DSAP lesions had no significant effect on the amount eaten or the latency to begin feeding. Forebrain-projecting CA neurons are therefore not required for water-activated compensatory feeding. Second, we compared the feeding behavior of DE-rats given back water to that of food-deprived rats given food. We also examined the neuronal activity in the hindbrain of these animals using Fos. Meal pattern analysis showed little difference between groups, once feeding was initiated. Dual IHC labeling for Fos and DBH showed no colocalization following drinking water and deficit induced feeding. This contrasts with 2DG stimulated feeding. Furthermore, we show that the Fos expression in particular parts of the nucleus of the solitary tract and the parabrachial nucleus is consistent their roles in projecting visceral and gustatory information to the hypothalamus to coordinate feeding. Thus water-activated compensatory feeding engages mechanisms similar to those used during food deprivation-induced feeding rather than glucoprivic feeding.

Related Products: Anti-DBH-SAP (Cat. #IT-03)

The effect of noradrenaline depletion on motor impairment and dopamine cell loss in a rat model of Parkinson’s disease.

Shin EJ, Rogers, J, Björklund A, Carta M (2013) The effect of noradrenaline depletion on motor impairment and dopamine cell loss in a rat model of Parkinson’s disease. Neuroscience 2013 Abstracts 623.12. Society for Neuroscience, San Diego, CA.

Summary: Objective: Parkinson’s disease (PD) has been mainly known as a neurodegenerative disease with loss of dopaminergic (DA) neurons in the substantia nigra. However, studies of post mortem PD brains have shown that not only DA neurons but also the noradrenergic (NA) neurons in the locus coeruleus degenerate, and that the NA neurodegeneration may be as profound, and also precedes degeneration of the midbrain DA neurons. The early involvement of the NA system is also in line with the caudal-to-rostral disease progression predicted by the model proposed by Braak et al. Hence, we have investigated the effect of NA depletion on motor deficits and DA cell loss in a rat PD model. Methods: To generate two lesion paradigms, rats were injected with a dopamine toxin, 6-OHDA in striatum and/or a NA toxin, DBH-saporin in lateral ventricles. Animals have been tested in a battery of behavioural tests to check the degree of motor impairment. Perfused tissues were then subjected to immunohistochemistry to assess the amount of degeneration in striatal DA fiber and nigral DA neurons. Results: In three motor tests (cylinder, amphetamine-induced rotation, and corridor tests) there was no significant difference in motor deficit between groups. However, the DA- and NA-lesioned animals showed more severe motor deficits than the DA-lesioned animals in stepping, staircase, and rotarod tests. Post mortem analysis revealed that NA depletion did not affect the degree of DA loss in striatum and substantia nigra determined by optical densitometry with tyrosine hydroxylase staining and stereological cell estimation with vesicular monoamine transporter staining, respectively. These results suggest that Parkinsonian-like motor symptoms could be worsened by NA degeneration but it is not due to more profound DA cell degeneration upon NA removal but maybe by dysregulated DA cell function.

Related Products: Anti-DBH-SAP (Cat. #IT-03)

Descending noradrenergic control of conditioned pain modulation and postoperative pain trajectory in rats.

Parker RA, Wang F, Hayashida K, Martin TJ, Eisenach JC, Peters CM (2013) Descending noradrenergic control of conditioned pain modulation and postoperative pain trajectory in rats. Neuroscience 2013 Abstracts 461.10. Society for Neuroscience, San Diego, CA.

Summary: Aim of Investigation: Chronic pain after surgery (CPAS) is now recognized as a significant clinical problem that occurs in 10-50% of patients undergoing surgery. Recent clinical studies demonstrate the integrity of endogenous pain inhibitory controls are important for preventing CPAS, however this relationship and underlying mechanisms haven't been examined in preclinical models. We hypothesized that a causal relationship exists between impaired endogenous analgesia and chronic pain after surgery that is in part dependent on descending noradrenergic pathways. Methods: We examined the integrity of endogenous analgesia in rats preoperatively used a previously described method for assessing conditioned pain modulation (CPM) in rats (Ferrari et al., 2010) involving injection of capsaicin (150μg/50μl) in the forepaw as a conditioning stimulus and detection of hindpaw mechanical thresholds (Randall-Selitto device) as the test stimulus. The partial L5 spinal nerve ligation (pSNL) model and mixed effects growth curve modeling of mechanical withdrawal thresholds assessed for 10 weeks following surgery were used to study resolution of postoperative mechanical hypersensitivity. The role of descending spinal noradrenergic pathways in CPM and postoperative trajectory was assessed by ablating spinal noradrenergic fibers with DβH-saporin or blocking their activity pharmacologically with adrenergic receptor antagonists. Results: Forepaw capsaicin resulted in release of NE in the lumbar spinal cord and this CPM paradigm was partially prevented by spinal idazoxan (30μg, i.t.). CPM assessed preoperatively resulted in pronounced but variable increases in hindpaw mechanical withdrawal thresholds at 30 minutes (range: 60-140g). Within individual rats, we observed a significant correlation between the degree of preoperative CPM and the slope of trajectory (P=0.006, r=0.610) as rats with lower endogenous analgesia had slower resolution of mechanical hypersensitivity. In support of a causal role between endogenous spinal noradrenergic activity and CPAS, depletion of spinal noradrenergic fibers prior to pSNL resulted in a significant reduction in the slope of trajectory within the ipsilateral hindpaw. Conclusions: Collectively, these studies suggest that the ability to engage descending endogenous noradrenergic pathways may be critical in determining whether CPAS develops. Furthermore, the use of growth curve modeling to study CPAS will allow us to examine the ability of socio-environmental conditions or pharmacological interventions to impair or improve aspects of postoperative pain trajectory as part of future studies.

Related Products: Anti-DBH-SAP (Cat. #IT-03)

Neuroprotection with gonadal steroids following partial motoneuron depletion: Dependence on steroid receptor activation and hormone action at the target musculature.

Sengelaub DR, Cai Y, Chung M, Mnayarji (2013) Neuroprotection with gonadal steroids following partial motoneuron depletion: Dependence on steroid receptor activation and hormone action at the target musculature. Neuroscience 2013 Abstracts 467.12. Society for Neuroscience, San Diego, CA.

Summary: Aim of Investigation: Chronic pain after surgery (CPAS) is now recognized as a significant clinical problem that occurs in 10-50% of patients undergoing surgery. Recent clinical studies demonstrate the integrity of endogenous pain inhibitory controls are important for preventing CPAS, however this relationship and underlying mechanisms haven't been examined in preclinical models. We hypothesized that a causal relationship exists between impaired endogenous analgesia and chronic pain after surgery that is in part dependent on descending noradrenergic pathways. Methods: We examined the integrity of endogenous analgesia in rats preoperatively used a previously described method for assessing conditioned pain modulation (CPM) in rats (Ferrari et al., 2010) involving injection of capsaicin (150μg/50μl) in the forepaw as a conditioning stimulus and detection of hindpaw mechanical thresholds (Randall-Selitto device) as the test stimulus. The partial L5 spinal nerve ligation (pSNL) model and mixed effects growth curve modeling of mechanical withdrawal thresholds assessed for 10 weeks following surgery were used to study resolution of postoperative mechanical hypersensitivity. The role of descending spinal noradrenergic pathways in CPM and postoperative trajectory was assessed by ablating spinal noradrenergic fibers with DβH-saporin or blocking their activity pharmacologically with adrenergic receptor antagonists. Results: Forepaw capsaicin resulted in release of NE in the lumbar spinal cord and this CPM paradigm was partially prevented by spinal idazoxan (30μg, i.t.). CPM assessed preoperatively resulted in pronounced but variable increases in hindpaw mechanical withdrawal thresholds at 30 minutes (range: 60-140g). Within individual rats, we observed a significant correlation between the degree of preoperative CPM and the slope of trajectory (P=0.006, r=0.610) as rats with lower endogenous analgesia had slower resolution of mechanical hypersensitivity. In support of a causal role between endogenous spinal noradrenergic activity and CPAS, depletion of spinal noradrenergic fibers prior to pSNL resulted in a significant reduction in the slope of trajectory within the ipsilateral hindpaw. Conclusions: Collectively, these studies suggest that the ability to engage descending endogenous noradrenergic pathways may be critical in determining whether CPAS develops. Furthermore, the use of growth curve modeling to study CPAS will allow us to examine the ability of socio-environmental conditions or pharmacological interventions to impair or improve aspects of postoperative pain trajectory as part of future studies.

Related Products: Anti-DBH-SAP (Cat. #IT-03)

Hindbrain catecholamine neurons control rapid switching of metabolic substrate use during glucoprivation in male rats.

Li AJ, Wang Q, Dinh TT, Wiater MF, Eskelsen AK, Ritter S (2013) Hindbrain catecholamine neurons control rapid switching of metabolic substrate use during glucoprivation in male rats. Endocrinology 154(12):4570-4579. doi: 10.1210/en.2013-1589

Summary: Previous work has shown that corticosterone secretion in response to glucoprivation is at least in part controlled by hindbrain catecholamine neurons in the paraventricular nucleus of the hypothalamus (PVH). In this work the authors investigate the metabolic consequences of lesioning these neurons. Rats received bilateral 82-ng infusions of Anti-DBH-SAP (Cat. #IT-03) into the PVH. Saporin (Cat. #PR-01) was used as a control. Although lesioned animals had the same energy expenditure and locomotor activity as controls, they also had a higher respiratory exchange ratio, indicating a reduced ability to switch from carbohydrate to fat metabolism in response to glucoprivation.

Related Products: Anti-DBH-SAP (Cat. #IT-03), Saporin (Cat. #PR-01)

A1 noradrenergic neurons lesions reduce natriuresis and hypertensive responses to hypernatremia in rats.

da Silva EF, Freiria-Oliveira AH, Custodio CH, Ghedini PC, Bataus LA, Colombari E, de Castro CH, Colugnati DB, Rosa DA, Cravo SL, Pedrino GR (2013) A1 noradrenergic neurons lesions reduce natriuresis and hypertensive responses to hypernatremia in rats. PLoS One 8(9):e73187. doi: 10.1371/journal.pone.0073187

Summary: Using bilateral 63-ng injections of Anti-DBH-SAP (Cat. #IT-03) into two levels of the caudal ventrolateral medulla, the authors assessed several pressor responses to infusion of hypertonic saline. Saporin (Cat. #PR-01) was used as a control. The results suggest that medullary noradrenergic A1 neurons are involved in the regulation of some responses to acute changes in body fluid composition.

Related Products: Anti-DBH-SAP (Cat. #IT-03), Saporin (Cat. #PR-01)

Implication of cerebral dopamine-beta hydroxylase for cardiovascular and mood regulation in rats.

Chang ST, Liu YP, Huang CL, Wang PY, Tung CS (2013) Implication of cerebral dopamine-beta hydroxylase for cardiovascular and mood regulation in rats. Chin J Physiol 56(4):209-218. doi: 10.4077/CJP.2013.BAB103

Summary: The ascending fibers affected by norepinephrine are involved in a variety of processes, including emotion, anxiety, and regulation of central autonomic outflows such as cardiovascular regulation and energy balance. The authors examined whether the loss of norephinephrine would cause autonomic failure in cardiovascular regulation. Rats received a single intraventricular injection of anti-DBH-SAP (Cat. #IT-03). Saporin (Cat. #PR-01) was used as a control. The results demonstrate that norepinephrine deficits in the brain influence reduction of excitatory responses to orthostatic stress.

Related Products: Anti-DBH-SAP (Cat. #IT-03), Saporin (Cat. #PR-01)

P2Y1 receptors expressed by C1 neurons determine peripheral chemoreceptor modulation of breathing, sympathetic activity, and blood pressure.

Wenker IC, Sobrinho CR, Takakura AC, Mulkey DK, Moreira TS (2013) P2Y1 receptors expressed by C1 neurons determine peripheral chemoreceptor modulation of breathing, sympathetic activity, and blood pressure. Hypertension 62(2):263-273. doi: 10.1161/HYPERTENSIONAHA.113.01487

Summary: Peripheral chemoreceptor activation response is mediated by catecholaminergic C1 cells in the rostral ventrolateral medulla (RVLM). The authors investigated the molecular mechanisms linking this drive to increased sympathetic activity and hypertension through a variety of methods, including lesioning C1 cells in the RVLM. Rats received 4.2-ng bilateral injections of Anti-DBH-SAP (Cat. #IT-03) into the RVLM. Comparison of lesioned animals to controls demonstrated that P2Y1 receptors on C1 cells in the RVLM are key components in the regulation of breathing, sympathetic nerve activity, and blood pressure.

Related Products: Anti-DBH-SAP (Cat. #IT-03)

Sudden death following selective neuronal lesions in the rat nucleus tractus solitarii.

Talman WT, Lin LH (2013) Sudden death following selective neuronal lesions in the rat nucleus tractus solitarii. Auton Neurosci 175(1-2):9-16. doi: 10.1016/j.autneu.2012.11.008

Summary: The nucleus tracts solitarii (NTS) is the terminus of cardiovascular reflex nerves. Early work in this area sought to identify transmitters involved in the control of this region. The authors used SSP-SAP (Cat. #IT-11) and anti-DBH-SAP (Cat. #IT-03) to examine the role of NK-1r-expressing neurons and catecholaminergic neurons in baroreflex control in the NTS. Either 3 ng of SSP-SAP or 42 ng of anti-DBH-SAP was injected into the NTS of rats and baroreflex function was compared 7 days later. Although each toxin had a specific effect in terms of the types of cells eliminated, both toxins initiated a disturbance of the central baroreflex control that led to the death of some animals.

Related Products: SSP-SAP (Cat. #IT-11), Anti-DBH-SAP (Cat. #IT-03)

Yohimbine anxiogenesis in the elevated plus maze requires hindbrain noradrenergic neurons that target the anterior ventrolateral bed nucleus of the stria terminalis.

Zheng H, Rinaman L (2013) Yohimbine anxiogenesis in the elevated plus maze requires hindbrain noradrenergic neurons that target the anterior ventrolateral bed nucleus of the stria terminalis. Eur J Neurosci 37(8):1340-1349. doi: 10.1111/ejn.12123

Summary: The anterior ventrolateral bed nucleus of the stria terminalis (vIBST) appears to be important for increased noradrenergic signaling to trigger anxiety-like behavior. 42.8 ng of anti-DBH-SAP (Cat. #IT-03) was administered to the vIBST of rats in bilateral injections. Elimination of noradrenergic neurons in the vIBST abolished yohimbine-induced anxiogenesis in an elevated plus maze, indicating that hindbrain noradrenergic neurons targeting the vIBST are involved in this mechanism.

Related Products: Anti-DBH-SAP (Cat. #IT-03)

Intact catecholamine inputs to the forebrain are required for appropriate regulation of corticotrophin-releasing hormone and vasopressin gene expression by corticosterone in the rat paraventricular nucleus.

Kaminski KL, Watts AG (2012) Intact catecholamine inputs to the forebrain are required for appropriate regulation of corticotrophin-releasing hormone and vasopressin gene expression by corticosterone in the rat paraventricular nucleus. J Neuroendocrinol 24(12):1517-1526. doi: 10.1111/j.1365-2826.2012.02363.x

Summary: Corticosterone releasing hormone (CRH) neurons in the paraventricular nucleus of the hypothalamus (PVH) control release of adrenocorticotropic hormone and glucocorticoids. In order to determine the contribution of these neurons to CRH and vasopressin expression in the PVH the authors administered bilateral 42 ng injections of anti-DBH-SAP (Cat. #IT-03) into the PVH of both normal and adrenalectomized rats. Mouse IgG-SAP (Cat. #IT-18) was used as a control. The data demonstrate that under certain conditions CRH and vasopressin gene expression is modulated by interactions between corticosterone and catecholaminergic projections to the hypothalamus.

Related Products: Anti-DBH-SAP (Cat. #IT-03), Mouse IgG-SAP (Cat. #IT-18)

Noradrenergic denervation by DBH saporin reduces behavioral responsivity to L-DOPA in the hemi-parkinsonian rat.

Ostock CY, Lindenbach D, Jaunarajs KL, Dupre KB, Goldenberg A, Bhide NS, Bishop C (2012) Noradrenergic denervation by DBH saporin reduces behavioral responsivity to L-DOPA in the hemi-parkinsonian rat. Neuroscience 2012 Abstracts 758.06. Society for Neuroscience, New Orleans, LA.

Summary: Dopamine (DA) replacement therapy with L-DOPA remains the most effective treatment for Parkinson’s disease (PD), but prolonged use frequently leads to deleterious side effects including involuntary choreic and dystonic movements known as L-DOPA induced dyskinesias (LID). It has been well established that DA loss in PD is accompanied by concomitant noradrenergic (NE) denervation of the locus coeruleus (LC); however, the contribution of NE loss to LID remains controversial and is often overlooked in traditional animal models of PD. Previous work from our lab demonstrated that rats with NE depletion induced by the selective NE neurotoxin DA beta hydroxylase saporin (DBH saporin) display reduced behavioral sensitivity to L-DOPA. The current investigation sought to further characterize the utility of DBH saporin lesions in a rodent model of PD by employing immunohistological techniques to correlate NE cell loss with behavioral outcome. Male Spraque-Dawley rats received unilateral 6-OHDA lesions of the medial forebrain bundle with intraventricular injections of either vehicle or DBH saporin. A number of well characterized behavioral tests were employed to determine lesion effects and L-DOPA responsiveness including: the abnormal involuntary movements scale for rodent dyskinesia, the forepaw adjusting steps (FAS) test as a metric of L-DOPA’s anti-parkinsonian efficacy, and locomotor chambers to observe motor performance. Sensitivity of primed animals to different doses of L-DOPA (0-12 mg/kg) and DA agonists SKF81297 (0., 0.08, 0.8 mg/kg) and Quinpirole (0, 0.05, 0.5 mg/kg) was assessed. Reduced behavioral responsiveness was associated with reductions in tyrosine hydroxylase positive cells within the LC of DBH saporin lesioned animals. Results indicate that NE denervation reduced anti-parkinsonian efficacy of L-DOPA on the FAS test. In primed rats, LC NE loss attenuated dyskinetic responses to L-DOPA and the DA agonist SKF81297. Taken together, these results indicate that DBH saporin lesions not only mimick the NE loss seen in idiopathic PD, but also reveal an underexplored contribution of the NE system to the manifestation of PD symptoms and LID.

Related Products: Anti-DBH-SAP (Cat. #IT-03)

Depletion of spinal norepinephrine increases the duration of postoperative pain related behaviors following acute plantar incision and partial nerve injury in the rat.

Wang F, Eisenach JC, Peters CM (2012) Depletion of spinal norepinephrine increases the duration of postoperative pain related behaviors following acute plantar incision and partial nerve injury in the rat. Neuroscience 2012 Abstracts 785.11. Society for Neuroscience, New Orleans, LA.

Summary: Background and Objective: The percentage of patients that develop chronic postsurgical pain can range from 10-50% depending on the type of surgery. The underlying mechanisms responsible for the transition from an acute to chronic postoperative pain state are unknown. Recent clinical studies suggest that the integrity of endogenous pain inhibitory circuits may be important for preventing this transition. The descending noradrenergic transmission has well-known inhibitory effects on spinal synaptic transmission and norepinephrine has anti-inflammatory effects on spinal glial activation. We hypothesized that disrupting spinal noradrenergic fibers in rats prior to peripheral tissue injury would enhance spinal glial activity and impair resolution of postoperative pain. Methods: To test this hypothesis, we used a model of acute pain (Brennan incision model) and a model of nerve injury involving partial L5 spinal nerve ligation. We intrathecally injected dopamine β hydroxylase conjugated to the ribosomal toxin saporin (DβH-sap, 5 μg) or control (IgG-sap) to Sprague-Dawley rats 14 days prior to surgery to deplete noradrenergic fibers. Sensitivity to mechanical stimuli (von Frey) and spontaneous guarding were assessed for several weeks. We used immunohistochemistry to assess microglial (IBA1) and astrocyte (GFAP) activation in spinal cord tissue. Results: Depletion of noradrenergic fibers resulted in a significant increase in the duration of mechanical hypersensitivity in the ipsilateral paw of rats with plantar incision (6 days in IgG-sap treated rats vs. at least 21 days in DβH-sap treated rats) and partial L5 spinal nerve ligation (42 days in IgG-sap treated rats vs. at least 70 days in DβH-sap treated rats). Depletion of noradrenergic fibers did not affect mechanical withdrawal thresholds in normal rats suggesting both tissue injury and spinal noradrenergic depletion were required for prolonged mechanical hypersensitivity. The duration of spontaneous guarding following plantar incision was not affected by DβH-sap treatment. Additionally, microglia and astrocyte activation was increased in the spinal cord 21 days following incision and 70 days after nerve injury in DβH-sap treated rats compared to IgG-sap treated rats. Conclusions: These findings highlight the crucial role of spinally projecting noradrenergic pathway in the resolution of incision and nerve injury induced hypersensitivity which may be due in part to inhibitory effect of norepinephrine on spinal glial activation. Future studies will focus on the adrenergic receptor subtypes and mechanisms responsible for the transition from acute to chronic postoperative pain in these models.

Related Products: Anti-DBH-SAP (Cat. #IT-03)

Selective damage to glia in the nucleus tractus solitarii attenuates cardiovascular reflexes.

Talman WT, Jones S, Nitschke Dragon D, Lin L-H (2012) Selective damage to glia in the nucleus tractus solitarii attenuates cardiovascular reflexes. Neuroscience 2012 Abstracts 524.05. Society for Neuroscience, New Orleans, LA.

Summary: Lesions of the nucleus tractus solitarii (NTS) are known to attenuate or abolish cardiovascular reflex responses. We have previously reported that lesions produced by saporin (SAP) conjugates and focused on neurons that express the neurokinin-1 (NK1) receptor or on other neurons that express both tyrosine hydroxylase (TH) and dopamine-β-hydroxylase (DBH), also attenuate baroreflex function in rats. We found that lesions of both types of neurons also led to loss of glia that stained with glial fibrillary acidic protein (GFAP). Further, we found that injection of SAP alone into the NTS led to loss of GFAP staining while leaving neurons in the region unaffected. Because both of the lesions directed at neurons were made by a toxic conjugate containing SAP, we sought to determine if SAP alone produced changes in cardiovascular reflex function. We found that injection of SAP (3 ng in 100 nl) into the NTS led to loss of the glial marker GFAP as well as connexin 43 (Cx43) immunofluorescent labeling in the NTS but did not affect the neuronal markers NMDAR1 (NMDA receptor subunit 1), GluR2 (AMPA receptor subunit 2), neuronal nitric oxide synthase (nNOS), TH, DBH, vesicular glutamate transporters (VGluTs), choline acetyl transferase (ChAT), NK1, and protein gene product 9.5 (PGP 9.5). In animals treated with bilateral injections of SAP into the NTS, reflex responses were decreased during testing of the baroreflex, the chemoreflex, or the von Bezold Jarisch reflex. Comparable decreases in baroreflex responses were seen in animals treated with SAP alone when compared with other animals treated with SAP conjugates that targeted and concentrated damage to TH/DBH neurons or NK1 neurons in NTS. In contrast, when TH/DBH neurons were targeted by the toxin 6-hydroxydopamine (6-OHDA) lability of arterial pressure did not occur as it did in the other SAP and SAP conjugate studies and reflex responses to the activation of the baroreflex, the chemoreflex, and the von Bezold Jarisch reflex did not differ from control. Furthermore, injections containing SAP or a SAP conjugate, but not those containing 6-OHDA, led to lability of arterial pressure as well as cardiac arrhythmias and cardiac myocytolysis. Our studies cannot exclude a physiological effect of SAP on neurons nor can it exclude an indirect effect of glial damage on NTS neurons. However, the similarity of responses when glia seem to have been targeted alone in contrast to those responses when select neuronal types seem to have been targeted suggests that each of the cardiovascular reflexes relies on intact glia in the NTS for full reflex expression.

Related Products: Anti-DBH-SAP (Cat. #IT-03), SSP-SAP (Cat. #IT-11)

Knockdown of noradrenergic locus coeruleus (LC) neurons alleviates chronic orofacial pain

Kaushal R, Ma F, Zhang L, Bright CR, Taylor BK, Westlund KN (2012) Knockdown of noradrenergic locus coeruleus (LC) neurons alleviates chronic orofacial pain. Neuroscience 2012 Abstracts 164.19. Society for Neuroscience, New Orleans, LA.

Summary: Trigeminal neuralgia (TN) is an excruciating and debilitating form of clinical orofacial pain. Noradrenergic locus coeruleus (LC, pontine A6 neurons) is involved in bidirectional modulation of pain. Multiple studies indicate that LC activity is increased during noxious stimulation and following inflammation or nerve damage. Predominantly known for its role in the feedback inhibition of pain, emerging studies also indicate a contribution of the LC in pain facilitation. For example, lesions of the LC significantly reduce tonic behavioral responses to intraplantar formalin injection, prevent autotomy, and reduce hypersensitivity associated with peripheral nerve injury. In this study we hypothesized that noradrenergic (LC) neurons contribute to the facilitation of chronic pain in TN. We used a rat model of TN involving infraorbital nerve chronic constriction injury (ION-CCI) which produces mechanical hypersensitivity as assessed by a reduction in von Frey threshold. Administration of anti-dopamine-β-hydroxylase saporin (anti-DβH-saporin) toxin was performed for selective elimination of noradrenergic LC neurons or IgG saporin (nonspecific) as the control either by intracerebroventricular (i.c.v space 2) or by bilateral spinal trigeminal nucleus (STN) injections. Under minimal restraint, rats received either no stimulation or repeated stimulation with either a 2 or 15-gm von Frey hair applied directly to the maxillary branch. Withdrawal threshold (tactile allodynia) from von Frey fiber stimulation to the face was not changed as compared to baseline in animals subjected to sham surgery; this was true in both saporin and anti-DβH-saporin groups. However, i.c.v. anti-DβH-saporin significantly increased withdrawal threshold animals with ION-CCI as compared to IgG saporin controls. More selective destruction of the LC-trigeminal pathway with bilateral STN anti-DβH-saporin injection also alleviated behavioral signs of chronic orofacial hyperalgesia. Elimination of noradrenergic LC neurons was confirmed by complete loss of tyrosine hydroxylase (TH) immunoreactivity in anti-DβH-saporin injected animals. Compared to unstimulated controls, mechanical stimulation increased immunoreactive phosphorylated extracellular cell-regulated protein kinase (pERK), a marker of neuronal activity, in the LC and STN. Nerve injury also increased expression of a neuronal injury and stress marker, activating transcription factor 3 (ATF3), in trigeminal ganglia neurons. Together, these results indicate that noradrenergic locus coeruleus neurons facilitate chronic orofacial neuropathic pain.

Related Products: Anti-DBH-SAP (Cat. #IT-03)

Catecholaminergic neurons in the ventrolateral medulla are differentially activated by the rate of fall in blood glucose during hypoglycemia, and are required for the rate-dependent hypoglycemic activation of sympathoadrenal responses.

Jokiaho A, Donovan C, Watts A (2012) Catecholaminergic neurons in the ventrolateral medulla are differentially activated by the rate of fall in blood glucose during hypoglycemia, and are required for the rate-dependent hypoglycemic activation of sympathoadrenal responses. Neuroscience 2012 Abstracts 93.05. Society for Neuroscience, New Orleans, LA.

Summary: Hypoglycemic counterregulation is mediated by glucosensors located in the hypothalamus, hindbrain, and portal-mesenteric veins (PV). We have previously shown that when hypoglycemia develops slowly PV glucose sensing is critical for both the sympathoadrenal response and hindbrain Fos activation. Hindbrain catecholaminergic (CA) neurons provide extensive inputs to the hypothalamus and are key participants in the control of energy homeostasis and in the responses to glycemic challenges. However, the role of the various CA cell groups together with the organization of the circuitry between peripheral and central glucose sensing units and the effectors that mediate counterregulatory response to hypoglycemia are unknown. To investigate the role of CA neurons in this network we use hyperinsulinemic-hypoglycemic clamps to induce fast (20mins)- or slow (75min)-onset hypoglycemia in male Wistar rats with saporin/anti-dopamine β-hydroxylase (DBH) DSAP immunotoxin lesions. The hypothalamic paraventricular nucleus (PVH) was injected bilaterally with DSAP or saporin conjugated to mouse IgG (SAP) as controls. PVH DSAP lesions remove about 80% of the DBH-ir and PNMT-ir cell bodies in the ventrolateral medulla. We found that hypothalamic CA afferents are required for sympathoadrenal (epinephrine and nor-epinephrine) responses to slow- but not fast-onset hypoglycemia. We also found robust Fos activation in CA neurons in the ventrolateral (A1, C1) and the dorsomedial medulla, particularly in the nucleus of the solitary tract (NTS; A2, C2). In rats with intact forebrain CA innervations, fast-onset hypoglycemia led to significantly greater DBH/Fos colocalization in the A1, A1/C1 and C1 regions compared to slow-onset hypoglycemia. We further identified substantial numbers of Fos-positive nuclei colocalized in adrenergic neurons (phenylethanolamine-N-methyltransferase (PNMT)) in the A1/C1 and C1 regions, and again these numbers were greater in fast-onset compared to slow-onset hypoglycemia. In SAP and DSAP animals, slow- and fast -onset hypoglycemia led to robust Fos expression in the area postrema and medial parts of the NTS. However, in these two regions there was virtually no Fos and DBH/PNMT-ir colocalization showing that AP and NTS neurons activated following hypoglycemia are not CA. The mechanisms that process the sensory information responsible for sympathoadrenal counterregulatory responses to fast- and slow-onset hypoglycemia are clearly different. We now show that different rates of hypoglycemia onset engage distinct CA cell groups, which in turn differentially participate in rate-dependent counterregulatory responses.

Related Products: Anti-DBH-SAP (Cat. #IT-03)

Lateral and fourth ventricular phloridzin injections stimulate feeding but do not produce hyperglycemia.

Li A-J, Wang Q, Smith BR, Ritter S (2012) Lateral and fourth ventricular phloridzin injections stimulate feeding but do not produce hyperglycemia. Neuroscience 2012 Abstracts 93.18. Society for Neuroscience, New Orleans, LA.

Summary: Sodium-coupled glucose transporters (SGLTs) are a family of glucose transporter found in small intestine, kidney, brain capillaries and some neurons. Because SGLTs are membrane receptors, they interact with extracellular glucose in a metabolism-independent manner. Early work using the SGLT inhibitor, phlorizin, suggested that fourth ventricular phlorizin injection increased feeding, but not blood glucose (Flynn FW and Grill HJ, 1985). To further examine this finding, we injected phloridzin, a competitive inhibitor for SGLT-1 and SGLT-2 into the lateral ventricle (LV) or the 4th ventricle (4V) in rats, and the effects of the injections on food intake and blood glucose were examined. We found that both LV and 4V injections of phloridzin enhanced food intake in rats and that LV and 4V injections were of similar potency. In contrast, neither injection elevated blood glucose levels in the present experiments. We also found that enhancement of feeding by 4V phloridzin was abolished by medial hypothalamic injections of anti-dopamine beta hydroxylase saporin, a retrogradely transported catecholamine immunotoxin that selectively lesions norepinephrine and epinephrine neurons that innervate the injection site. Taken together, these results suggest that SGLT receptors in the brain constitute a novel, nonmetabolic, glucose sensing mechanism that contribute to control of food intake.

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Nucleus of the solitary tract catecholaminergic neurons modulate the cardiovascular response to psychological stress in rats.

Daubert DL, McCowan M, Erdos B, Scheuer DA (2012) Nucleus of the solitary tract catecholaminergic neurons modulate the cardiovascular response to psychological stress in rats. J Physiol 590(Pt 19):4881-4895. doi: 10.1113/jphysiol.2012.232314

Summary: It has been proposed that the nucleus of the solitary tract (NTS) is highly involved in cardiovascular regulation. In light of the fact that catecholaminergic neurons in the NTS are part of stress-related neurocircuitry, the authors investigated whether these neurons attenuate blood pressure increases due to stress. Rats received 22 ng bilateral injections of anti-DBH-SAP (Cat. #IT-03) into the NTS. Mean arterial pressure and baseline plasma epinephrine were measured in a restraint test. Animals lesioned with anti-DBH-SAP displayed a significantly enhanced mean arterial pressure, and reduced plasma epinephrine. These data suggest that catecholaminergic neurons in the NTS inhibit the arterial pressure response to stress, but maintain the corticosteroid response.

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Control of sleep and wakefulness.

Brown RE, Basheer R, McKenna JT, Strecker RE, McCarley RW (2012) Control of sleep and wakefulness. Physiol Rev 92(3):1087-1187 . doi: 10.1152/physrev.00032.2011

Summary: This review summarizes mechanisms in the brain that control sleep and wakefulness. Areas discussed include wakefulness promoting systems, non-REM sleep and REM sleep definitions, the function of each kind of sleep, and dysfunction that occurs as a result of sleep disruption. Several targeted conjugates are mentioned, such as 192-IgG-SAP (Cat. #IT-01), anti-DBH-SAP (Cat. #IT-03), and orexin-SAP (Cat. #IT-20). The review summarizes the use of these products to better understand sleep networks.

Related Products: 192-IgG-SAP (Cat. #IT-01), Anti-DBH-SAP (Cat. #IT-03), Orexin-B-SAP (Cat. #IT-20)

Effects of noradrenergic alpha-2 receptor antagonism or noradrenergic lesions in the ventral bed nucleus of the stria terminalis and medial preoptic area on maternal care in female rats.

Smith CD, Holschbach MA, Olsewicz J, Lonstein JS (2012) Effects of noradrenergic alpha-2 receptor antagonism or noradrenergic lesions in the ventral bed nucleus of the stria terminalis and medial preoptic area on maternal care in female rats. Psychopharmacology (Berl) 224(2):263-276. doi: 10.1007/s00213-012-2749-2

Summary: The authors investigated the function of norepinephrine in mothering. Lesioned animals received 55-ng infusions of anti-DBH-SAP (Cat. #IT-03) into the ventral bed nucleus of the stria terminalis. Mouse-IgG-SAP (Cat. #IT-18) was used as a control. The results demonstrate that downregulated noradrenergic activity is necessary for postpartum maternal behavior, but is not enough to elicit maternal behavior in nulliparous females.

Related Products: Anti-DBH-SAP (Cat. #IT-03), Mouse IgG-SAP (Cat. #IT-18)

A2 noradrenergic lesions prevent renal sympathoinhibition induced by hypernatremia in rats.

Pedrino GR, Freiria-Oliveira AH, Almeida Colombari DS, Rosa DA, Cravo SL (2012) A2 noradrenergic lesions prevent renal sympathoinhibition induced by hypernatremia in rats. PLoS One 7(5):e37587. doi: 10.1371/journal.pone.0037587

Summary: It is thought that renal sympathetic nerve activity is a key component of the response to acute or chronic elevated concentrations of saline in the blood stream. The authors investigated what neurons are involved in the central control of these responses. Rats received bilateral 6.3 ng injections of anti-DBH-SAP (Cat. #IT-03) into the nucleus of the solitary tract. An equimolar amount (1.3 ng) of saporin (Cat. #PR-01) was used as a control. Loss of the A2 noradrenergic neurons altered the renal sympathetic nerve activity response to elevated saline, suggesting that these neurons help regulate the extracellular fluid compartment.

Related Products: Anti-DBH-SAP (Cat. #IT-03), Saporin (Cat. #PR-01)

Sudden death and myocardial lesions after damage to catecholamine neurons of the nucleus tractus solitarii in rat.

Talman WT, Dragon DN, Jones SY, Moore SA, Lin LH (2012) Sudden death and myocardial lesions after damage to catecholamine neurons of the nucleus tractus solitarii in rat. Cell Mol Neurobiol 32(7):1119-1126. doi: 10.1007/s10571-012-9835-1

Summary: Previous work has shown that elimination of neurons expressing the neurokinin-1 receptor (NK1r) from the nucleus tractus solitarii (NTS) causes various circulatory system dysfunctions, often leading to sudden death. The authors injected the brainstem of rats with 42 ng anti-DBH-SAP (Cat. #IT-03). to eliminate catecholaminergic neurons in the NTS that express tyrosine hydroxylase. This elimination had similar cardiac and cardiovascular effects to the elimination of NK1r-expressing neurons.

Related Products: Anti-DBH-SAP (Cat. #IT-03)

Control of the central chemoreflex by A5 noradrenergic neurons in rats.

Taxini CL, Takakura AC, Gargaglioni LH, Moreira TS (2011) Control of the central chemoreflex by A5 noradrenergic neurons in rats. Neuroscience 199:177-186. doi: 10.1016/j.neuroscience.2011.09.068

Summary: The A5 group of noradrenergic neurons in the ventrolateral pons is involved in the control of sympathetic and respiratory networks. Using anti-DBH-SAP (Cat. #IT-03) the authors eliminated TH+ neurons in order to clarify which aspects of respiration are modulated by A5 neurons. Rats received bilateral 4.2-ng injections of the toxin into the A5 region. The results suggest that A5 noradrenergic neurons are involved in control of mean arterial pressure, splanchnic sympathetic nerve activity, and phrenic nerve activity.

Related Products: Anti-DBH-SAP (Cat. #IT-03)

MAP kinases couple hindbrain-derived catecholamine signals to hypothalamic adrenocortical control mechanisms during glycemia-related challenges.

Khan AM KKL, Sanchez-Watts, Ponzio TA, Kuzmiski JB, Bains JS, Watts AG (2011) MAP kinases couple hindbrain-derived catecholamine signals to hypothalamic adrenocortical control mechanisms during glycemia-related challenges. J Neurosci 31(50):18479-18491. doi: 10.1523/JNEUROSCI.4785-11.2011

Summary: This work uses in vivo and ex vivo techniques to clarify how hypothalamic afferent pathways use intracellular mechanisms to modulate glycemia related adrenocortical responses. Rats received 42 ng injections of anti-DBH-SAP (Cat. #IT-03) into the paraventricular nucleus of the hypothalamus. Mouse IgG-SAP (Cat. #IT-18) was used as a control. The results establish a relationship between neurons from nutrient-sensing regions and intracellular mechanisms in hypothalamic corticotropin-releasing hormone neuroendocrine neurons.

Related Products: Anti-DBH-SAP (Cat. #IT-03), Mouse IgG-SAP (Cat. #IT-18)

Depletion of endogenous noradrenaline does not prevent spinal cord plasticity following peripheral nerve injury.

Hayashida K, Peters CM, Gutierrez S, Eisenach JC (2012) Depletion of endogenous noradrenaline does not prevent spinal cord plasticity following peripheral nerve injury. J Pain 13(1):49-57. doi: 10.1016/j.jpain.2011.09.009

Summary: The authors examined what involvement noradrenergic fibers in the spinal cord have in neuronal and glial plasticity associated with neuropathic pain states. Rats received 5 μg intrathecal injections of anti-DBH-SAP (Cat. #IT-03). Lesioned animals did not display altered mechanical withdrawal thresholds, but L5-L6 spinal nerve ligation in these animals caused enhanced mechanical hypersensitivity and analgesia induced by intrathecal clonidine. The data suggest that endogenous noradrenaline may play an inhibitory role on glial activation.

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Redefining the components of central CO2 chemosensitivity – towards a better understanding of mechanism.

Huckstepp RT, Dale N (2011) Redefining the components of central CO2 chemosensitivity - towards a better understanding of mechanism. J Physiol 589(Pt 23):5561-5579. doi: 10.1113/jphysiol.2011.214759

Summary: This review discusses advances in the field of CO2 chemosensitivity over the past few years. Discussion of the role that locus coeruleus (LC) neurons play in this process describe the use of anti-DBH-SAP (Cat. #IT-03) to reduce the hypercapnic ventilatory response. Data from these and other experiments support a role of the LC in modulation of the ventilatory response to hypercapnia.

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Norepinephrine denervation by dopamine beta-hydroxylase saporin impacts L-DOPA efficacy and side effects in a hemi-parkinsonian rat model

Bhide NS, Dickinson S, Feinberg E, Mohamed M, Dupre K, Eskow-Jaunarajs K, Lindenbach D, Ostock C, Bishop C (2011) Norepinephrine denervation by dopamine beta-hydroxylase saporin impacts L-DOPA efficacy and side effects in a hemi-parkinsonian rat model. Neuroscience 2011 Abstracts 883.20. Society for Neuroscience, Washington, DC.

Summary: Dopaminergic neurodegeneration in Parkinson’s disease (PD) is accompanied by concomitant loss in the norepinephrine (NE) system. The exact contribution of NE denervation in the development of PD remains elusive. Recently, we demonstrated that NE neurons may contribute to the efficacy and side effects of L-DOPA, however, to better mimic NE loss observed in PD we employed the selective NE neurotoxin dopamine beta hydroxylase saporin (DHB saporin) and evaluated its effects on the anti-parkinsonian efficacy of L-DOPA and the development & expression of L-DOPA induced dyskinesia (LID). To do so, hemiparkinsonian adult Sprague-Dawley rats were exposed to intraventricular injections of either vehicle or DHB saporin. Three weeks later, animals were primed with L-DOPA (4mg/kg) for days 1-7 and L-DOPA (12 mg/kg) for days 9-15. During this period animals were monitored for motor-performance, a marker for L-DOPA’s anti-parkinsonian efficacy, and dyskinesia measured using Abnormal Involuntary Movements (AIMs) scale. Further, sensitivity of primed animals to different doses of L-DOPA (ranging from 2 to 12 mg/kg) was assessed. Results indicate that NE denervation resulted in reduced anti-parkinsonian efficacy of L-DOPA, but not the development of dyskinesia. In fully primed rats, NE denervation attenuated dyskinetic responses to L-DOPA when compared to animals with an intact NE innervation. These findings suggest that the NE system significantly modulates the anti-parkinsonian effects of L-DOPA and the expression of LID and indicate the importance of understanding the mechanisms by which NE modifies basal ganglia function in PD.

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Fourth ventricular glucosamine-induced feeding is catecholamine-dependent

Li AJ, Wang Q, Ritter S (2011) Fourth ventricular glucosamine-induced feeding is catecholamine-dependent. Neuroscience 2011 Abstracts 600.17. Society for Neuroscience, Washington, DC.

Summary: Glucokinase has been identified as a glucose-sensor for detecting glucose changes both in the brain and periphery. Previous reports have shown that lateral ventricular injection of a glucokinase inhibitor, glucosamine, stimulates glucoprivic feeding in rats. Other work has demonstrated involvement of hindbrain glucokinase in glucoregulation. Here we compared the effects of lateral (LV) and fourth ventricular (4V) injections of glucosamine on food intake in rats. We found that glucosamine injected into 4V (0, 0.2, 0.6, and 1.0 mg/rat) enhanced food intake in a dose-dependent manner and that LV and 4V injections were of similar potency. Glucosamine did not elevate blood glucose under the conditions of our test. We also found that enhancement of feeding by 4V glucosamine was abolished by medial hypothalamic injections of anti-dopamine beta hydroxylase saporin, a retrogradely transported catecholamine immunotoxin that selectively lesions norepinephrine and epinephrine neurons that innervate the injection site. Furthermore, 4V injection of glucosamine increased Fos expression in catecholamine populations responsible for key glucoregulatory responses. These results demonstrate that glucokinase in hindbrain catecholamine neurons is a mediator of food intake and possibly a transduction mechanism for stimulation of glucoregulatory feeding by these neurons.

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Cardiovascular dysfunction and cardiac injury result from selective glial damage in the nucleus tractus solitarii

Talman WT, Nitschke Dragon D, Jones S, Moore SA, Lin L-H (2011) Cardiovascular dysfunction and cardiac injury result from selective glial damage in the nucleus tractus solitarii. Neuroscience 2011 Abstracts 664.14. Society for Neuroscience, Washington, DC.

Summary: In man, extensive CNS dysfunction as may occur after subarachnoid hemorrhage may lead to cardiac damage and cardiac arrhythmias. We have shown that highly selective and restricted lesions of the nucleus tractus solitarii (NTS) may lead to similar cardiac and cardiovascular compromise. For example, using conjugates including the cytotoxin saporin (SAP) to selectively damage NTS neurons that express NK1 receptors or those that express tyrosine hydroxylase (TH) leads to cardiac dysfunction and associated lability of arterial pressure. In continuing efforts to better characterize cellular changes produced by introducing into the NTS conjugates containing SAP, we have studied the effect of anti-dopamine-beta-hydroxylase (anti-DBH)-SAP, stabilized substance P (SSP)-SAP, SAP (unconjugated), blank-SAP (non-targeted peptide conjugate), IgG-SAP (non-targeted immunoglobulin conjugate), and 6-hydoxydopamine (6-OHDA) as a control without SAP injected into NTS. We assessed effects of the injected agents both on cellular markers [NMDAR1 (NMDA receptor subunit 1), GluR2 (AMPA receptor subunit 2), gamma-aminobutyric acid (GABA) receptor type a and b, neuronal nitirc oxide synthase (nNOS), TH, vesicular glutamate transporters (VGluTs), choline acetyl transferase (ChAT), glial fibrillary acidic protein (GFAP), connexin 43 (Cx43), DBH and protein gene product 9.5 (PGP 9.5)] and on cardiovascular and cardiac function. We have found that each compound containing SAP (including blank-SAP, IgG-SAP, unconjugated SAP) led to loss of GFAP and Cx43 immunofluorescent labeling in the NTS as well as lability of arterial pressure, cardiac arrhythmias, and cardiac myocytolysis. Those outcomes occurred despite neuronal specificity for each of the SAP conjugates. For example, anti-DBH-SAP led to a decrease in TH and DBH staining as well as a profound loss in GFAP and Cx43. In contrast, SSP-SAP led to loss of NK1 as well as GFAP, Cx43, and glutamate receptor markers but did not lead to loss of DBH or GABA. SSP-SAP also caused a loss in PGP9.5 which was not observed in all other agents. SAP and blank-SAP, on the other hand, led to loss of GFAP and Cx43 while 6-OHDA led to loss of TH and DBH, increased GFAP and decreased Cx-43. We are still investigating the effects of 6-OHDA on lability of arterial pressure and cardiac events but preliminary data suggest that, in doses used, it led to loss of TH and DBH but did not lead to either lability or cardiac events that were seen with each of the conjugates containing an SAP moiety. This study suggests that glial dysfunction may alone interefere with cardiovascular control through the NTS and may lead to cardiac damage and cardiovascular dysfunction.

Related Products: Anti-DBH-SAP (Cat. #IT-03), SSP-SAP (Cat. #IT-11), Mouse IgG-SAP (Cat. #IT-18), Blank-SAP (Cat. #IT-21), Saporin (Cat. #PR-01)

The effects of noradrenergic lesions to the orbitofrontal cortex on reversal learning

Bates AT, Duys AN, Miller CE, Miller R, Mcgaughy J (2011) The effects of noradrenergic lesions to the orbitofrontal cortex on reversal learning. Neuroscience 2011 Abstracts 296.03. Society for Neuroscience, Washington, DC.

Summary: Poor impulse control is one of the major symptoms of disorders such as attention deficit disorder and is hypothesized to result from dysfunction in the prefrontal cortex. Specifically the ability to inhibit responding to a previously reinforced stimulus as required in tests of reversal rely on the functional integrity of the orbitofrontal cortex. Previous work from our lab and others have shown that norepinephrine in the prelimbic cortex is necessary to perform attentional set shifting. Lesions to this region result in attentional set shifting impairments that can be remediated by the administration of a selective noradrenergic reuptake blocker. Though many studies have shown monoamine levels in the orbitofrontal cortex are critical to reversal learning, few studies have directly addressed the impact of norepinephrine depletion in the orbitofrontal cortex on reversal learning. In the present study, we assess the effects of noradrenergic deafferentation of the orbitofrontal cortex in the intra-dimensional/extra-dimensional set shifting task using adult male, Long-Evans hooded rats. Preliminary data support the hypothesis that norepinephrine in orbitofrontal cortex is critical to successful reversal learning as the lesioned animals required more trials to reach criterion performance on reversals than sham-lesioned rats. Performance on the ID and ED portions of the task were not impacted by lesion. After behavioral testing was completed, brains were processed to elucidate norepinephrine transporters (NET). Fiber density of NET positive fibers was assessed in the regions of the orbitofrontal, prelimbic, and cingulate cortices for all subjects. These findings point to the function of the noradrenergic system within the orbitofrontal cortex on mediating impulse control while leaving attentional set shifting performance intact.

Related Products: Anti-DBH-SAP (Cat. #IT-03)

Basal metabolic substrate utilization is altered by lesion of hindbrain catecholamine neurons that innervate the medial hypothalamus and substrate selection during glucoprivation is impaired.

Ritter S, Li A-J, Wang Q, Dinh TT (2011) Basal metabolic substrate utilization is altered by lesion of hindbrain catecholamine neurons that innervate the medial hypothalamus and substrate selection during glucoprivation is impaired. Neuroscience 2011 Abstracts 88.05. Society for Neuroscience, Washington, DC.

Summary: Central injection of the targeted immunotoxin, anti-dopamine beta hydroxylase (DBH)-saporin (DSAP), retrogradely and selectively lesions norepinephrine (NE) and epinephrine (E) neurons with projections to the injection site. Previous work has shown that DSAP injections targeting the hypothalamic paraventricular nucleus eliminate key counterregulatory responses to acute glucose deficit, including feeding and corticosterone secretion. To examine the role of these NE an E neurons in metabolic control under basal conditions, we injected rats in the PVH with DSAP or control unconjugated saporin (SAP) and analyzed their metabolic profiles using metabolic chambers (Columbus Instruments). Rats were maintained on a standard pelleted rodent diet. We found that the respiratory exchange ratio (RER) was consistently elevated in DSAP rats across the entire circadian cycle under basal conditions, compared to the RER of SAP controls, indicating increased dependence on carbohydrate utilization. Metabolic rate and activity did not differ between groups. This result suggests a chronic enhancement of glucose mobilization or an impairment of the ability to mobilize fatty acids in the DSAP rats. We also found that when challenged by 2-deoxy-D-glucose induced glucoprivation, SAP controls exhibited a rapid decrease in RER, indicating a switch to fat metabolism, whereas DSAP rats did not exhibit this response. Together these results favor the possibility that a central mechanism for fat mobilization is impaired in DSAP rats and that this impairment is reflected under both basal and glucoprivic conditions. The previously reported observation that PVH DSAP-injected rats exhibit a slowly-developing obesity also supports this possibility. Additional findings suggest that this impairment may be due to the loss of NE/E control of corticosterone secretion in the DSAP rats.

Related Products: Anti-DBH-SAP (Cat. #IT-03), , Saporin (Cat. #PR-01)

Diminished norepinephrine release in the BSTv decreases anxiety but does not promote maternal behavior in nulliparous female rats.

Holschbach MA, Lonstein JS (2011) Diminished norepinephrine release in the BSTv decreases anxiety but does not promote maternal behavior in nulliparous female rats. Neuroscience 2011 Abstracts 86.06. Society for Neuroscience, Washington, DC.

Summary: Postpartum caregiving heavily depends on both increased motivation to interact with offspring and decreased emotional reactivity. The early postpartum period is associated with reduced anxiety in mammals, which may promote contact with potentially anxiogenic young. The ventral bed nucleus of the stria terminalis (BSTv) is associated with both anxiety and maternal behaviors in laboratory rats and may be a site of integration for mediating tradeoffs between mothering and emotional reactivity. Our laboratory has previously shown that increasing norepinphrine (NE) release in the BSTv of postpartum rats via infusion of an autoreceptor antagonist increases dams’ anxiety behaviors to levels seen in untreated virgin rats. Interestingly, this treatment also disrupts maternal retrieval of pups (Smith and Lonstein, SFN 2009). Unlike postpartum rats, nulliparous females are not spontaneously maternal, and we hypothesized that if NE release in the BSTv disrupts maternal behaviors even in highly motivated postpartum rats, it may greatly hinder expression of maternal behaviors in virgins. To investigate whether depleting NE input to the BSTv is sufficient to reduce anxiety and promote maternal behavior in virgin female rats we injected an antiserum- based neurotoxin selective for noradrenergic fibers and cells (anti-dopamine beta-hydroxylase-saporin; anti-DBH-SAP; 50 mg/side), into the BSTv of ovariectomized virgin female rats. Two weeks later, we examined females’ anxiety behavior in an elevated plus maze and the next day began a maternal sensitization procedure. We placed three recently fed pups into each animal’s homecage and observed behavior for the following fifteen minutes each day until rats exhibited full maternal behavior (i.e. retrieved all three pups to a common nest site and hovered over them) during three consecutive tests. Histological analysis of the brains confirmed that anti-DBH-SAP greatly reduced NE fiber content in the BSTv. Compared to control animals injected with artificial CSF, animals injected with anti-DBH-SAP showed reduced anxiety in an elevated plus maze. Anti-DBH-SAP did not, however, reduce the latency to show full maternal behavior. Thus, although reduced anxiety permits or promotes expression of maternal behaviors in already motivated postpartum rats, reducing BSTv-mediated anxiety is not sufficient to facilitate maternal responsiveness without otherwise activating maternal motivational systems.

Related Products: Anti-DBH-SAP (Cat. #IT-03)

Phox2b-expressing neurons of the parafacial region regulate breathing rate, inspiration, and expiration in conscious rats.

Abbott SB, Stornetta RL, Coates MB, Guyenet PG (2011) Phox2b-expressing neurons of the parafacial region regulate breathing rate, inspiration, and expiration in conscious rats. J Neurosci 31(45):16410-16422. doi: 10.1523/JNEUROSCI.3280-11.2011

Summary: Neurons in the retrotrapezoid nucleus (RTN) are involved in the CO2-dependent control of breathing in conscious and anesthetized rats. In this work the authors specifically examined Phox2b-expressing glutaminergic neurons in the RTN. Rats received 44 ng of DBH-SAP (Cat. #IT-03) into the lateral horn of the second thoracic segment in order to eliminate C1 neurons that project to the spinal cord. The data demonstrate regulation of lung ventilation by RTN-Phox2b neurons, and also that these neurons are not rhythmogenic in adults.

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The sympathetic nervous system stimulates anti-inflammatory B cells in collagen-type II-induced arthritis.

Pongratz G, Melzer M, Straub R (2012) The sympathetic nervous system stimulates anti-inflammatory B cells in collagen-type II-induced arthritis. Ann Rheum Dis 71(3):432-9. doi: 10.1136/ard.2011.153056

Summary: The sympathetic nervous system exerts anti-inflammatory effects on collagen-induced arthritis. To examine whether these effects are mediated by B-cells producing interleukin-10 (IL-10) the authors treated mice with 5 µg intraperitoneal injections of anti-DBH-SAP (Cat. #IT-03). The sympathectomy efficacy was assessed by analyzing norepinephrine levels in the spleen. The data suggest that increasing the number of IL-10 producing B cells can slow down arthritis progression.

Related Products: Anti-DBH-SAP (Cat. #IT-03)

Minireview: The value of looking backward: the essential role of the hindbrain in counterregulatory responses to glucose deficit.

Ritter S, Li AJ, Wang Q, Dinh TT (2011) Minireview: The value of looking backward: the essential role of the hindbrain in counterregulatory responses to glucose deficit. Endocrinology 152(11):4019-4032. doi: 10.1210/en.2010-1458

Summary: This review examines work addressing how particular glucose-sensing cells function in glucoregulation under specific physiological or pathological conditions. There are specific populations of norepinephrine (NE) and epinephrine (E) neurons in the hindbrain that mediate these responses. The use of anti-DBH-SAP (Cat. #IT-03) to eliminate selective NE/E subgroups without disrupting basic functions is discussed.

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Patterning of somatosympathetic reflexes reveals nonuniform organization of presympathetic drive from C1 and non-C1 RVLM neurons.

Burke PG, Neale J, Korim WS, McMullan S, Goodchild AK (2011) Patterning of somatosympathetic reflexes reveals nonuniform organization of presympathetic drive from C1 and non-C1 RVLM neurons. Am J Physiol Regul Integr Comp Physiol 301(4):R1112-R1122. doi: 10.1152/ajpregu.00131.2011

Summary: Some neurons in the rostral ventrolateral medulla are part of the circuitry that helps maintain blood pressure. This control is exerted through both feed-forward and reflex adjustment mechanisms. The authors used bilateral injections of anti-DBH-SAP (Cat. #IT-03, 24 ng per side) into the spinal cord of rats between T1 and T2 to better understand the organization of this circuitry. Mouse IgG-SAP (Cat. #IT-18) was used as a control. The results suggest that myelinated neurons may control baseline tone, while stressor response uses unmyelinated neurons.

Related Products: Anti-DBH-SAP (Cat. #IT-03), Mouse IgG-SAP (Cat. #IT-18)

Brain stem catecholamines circuitry: Activation by alcohol and role in the hypothalamic-pituitary-adrenal response to this drug.

Lee S, Craddock Z, Rivier C (2011) Brain stem catecholamines circuitry: Activation by alcohol and role in the hypothalamic-pituitary-adrenal response to this drug. J Neuroendocrinol 23(6):531-541. doi: 10.1111/j.1365-2826.2011.02131.x

Summary: In this work the authors investigated mechanisms underlying the stimulatory effect of alcohol on the hypothalamic-pituitary-adrenal axis (HPA). One method used was 33-ng injections of anti-DBH-SAP (Cat. #IT-03) into the A2/C2/C3 and A1/C1 regions. The data generated show that catecholamines, especially in the brainstem, regulate the HPA response to alcohol. This regulation utilizes α1-adrenergic receptors. Administration of anti-DBH-SAP to the A1-A2/C1-C3 regions disrupted the catecholaminergic input to the paraventricular nucleus.

Related Products: Anti-DBH-SAP (Cat. #IT-03)

Participation of hindbrain AMP-activated protein kinase in glucoprivic feeding.

Li AJ, Wang Q, Ritter S (2011) Participation of hindbrain AMP-activated protein kinase in glucoprivic feeding. Diabetes 60(2):436-442. doi: 10.2337/db10-0352

Summary: Catecholamine neurons innervating the medial hypothalamus are involved in the control of glucoprivic feeding as well as other responses to glucose deficit. Rats received bilateral 82-ng injections of anti-DBH-SAP (Cat. #IT-03) into the paraventricular hypothalamic nucleus. Saporin (Cat. #PR-01) was used as a control. Lesioned animals did not respond to the administration of a competitive glucose inhibitor, nor did they display phosphorylation of pAMPKα, suggesting that AMPK may be part of a glucose- sensing mechanism.

Related Products: Anti-DBH-SAP (Cat. #IT-03), Saporin (Cat. #PR-01)

Featured Article: Targeted lesion of caudal brainstem catecholamine neurons reveals their role in symptoms of fatigue

Goehler LE, Gaykema RPA (2011) Featured Article: Targeted lesion of caudal brainstem catecholamine neurons reveals their role in symptoms of fatigue. Targeting Trends 12(1)

Related Products: Anti-DBH-SAP (Cat. #IT-03), Mouse IgG-SAP (Cat. #IT-18)

Read the featured article in Targeting Trends.

Defining the role of norepinephrine in cannabinoid-induced aversion and anxiety

Carvalho AF, Van Bockstaele E (2010) Defining the role of norepinephrine in cannabinoid-induced aversion and anxiety. Neuroscience 2010 Abstracts 833.3. Society for Neuroscience, San Diego, CA.

Summary: In the central nervous system, cannabinoids have been shown to regulate neurotransmitter release, control the hypothalamic-pituitary-adrenal axis and impact several physiological systems, such as food intake, pain and emotion perception. Manipulation of the cannabinoid system using exogenous compounds has been explored as a potential therapeutic for several disorders; however some severe side effects have been reported. Understanding the neural circuits and neurochemical substrates impacted by cannabinoids will provide a better means of gauging their actions within the central nervous system that may contribute to the expression of unwanted side effects. Previous work from our lab had shown that the cannabinoid receptor (CBr) agonist WIN 55,212-2 is able to induce changes in noradrenergic transmission in limbic structures such as prefrontal cortex (PFC) and the nucleus accumbens (Acb). Moreover, we have previously reported that norepinephrine in the nucleus accumbens (Acb) is critical for WIN 55,212-2-induced aversion, as measured by the place conditioning paradigm. In the present study, we further explore the role of norepinephrine in cannabinoid-induced behaviors. More specifically, we investigate whether norepinephrine in the limbic forebrain of rats is important for the anxiety induced by WIN 55,212-2 (3.0 mg/kg, i.p.). Lesion of noradrenergic neurons in the Acb and bed nucleus of the stria terminalis (BNST) was achieved by the intracerebral injection of the toxin saporin conjugated with an antibody that recognizes the enzyme dopamine-beta-hydroxylase (DBH). This toxin yields a specific lesion of noradrenergic neurons. The anxiogenic effects of WIN 55,212-2 were then measured in the elevated zero maze. The results show that depletion of noradrenergic innervation of the Acb and BNST did not reduce the anxiogenic properties of WIN 55,212-2. These results, together with our previous findings, suggest that the anxiogenic and aversive properties of the CBr agonist WIN 55,212-2 are differentially regulated, with the aversive effects being dependent on noradrenergic transmission within the Acb and the anxiogenic effects being regulated by a, yet to be determined, alternative mechanism/circuit.

Related Products: Anti-DBH-SAP (Cat. #IT-03)

Patterning of somatosympathetic reflexes: Identification of distinct bulbospinal sympathoexcitatory RVLM projections by conduction velocity and catecholamine phenotype

Burke PG, Neale J, Korim WS, Mcmullan S, Pilowsky PM, Goodchild AK (2010) Patterning of somatosympathetic reflexes: Identification of distinct bulbospinal sympathoexcitatory RVLM projections by conduction velocity and catecholamine phenotype. Neuroscience 2010 Abstracts 694.11/HHH34. Society for Neuroscience, San Diego, CA.

Summary: The aim of this study was to examine the somatosympathetic reflex (SSR) response of different sympathetic nerves to identify distinct projections of presympathetic vasomotor RVLM neurons by axonal conduction and catecholamine phenotype. All experiments were conducted in urethane-anaesthetised (1.3 g/kg ip), paralysed, vagotomised and artificially ventilated Sprague Dawley rats (n = 44). First, we determined the simultaneous activity of dorsal root potentials and the splanchnic SSR to single shock sciatic nerve (SN) stimulation (single 0.2 ms pulse, 50 sweeps at 0.5-1 Hz, 1-80 V, n=4). Second, we simultaneously recorded the sympathoexcitatory response of multiple, sympathetic nerves (cervical, renal, splanchnic and lumbar) to low (A-fibre afferent; 4-10 V) and high (A- and C-fibre afferents; +40 V) SN stimulation (n=19). Third, we examined the cervical or splanchnic SSR to low intensity SN stimulation in rats following RVLM microinjection of somatostatin (SST) or muscimol (n=8). Fourth, we examined the splanchnic SSR in rats pretreated with intraspinal anti-dopamine-beta-hydroxylase-saporin (anti-DβH-SAP; 24 ng/side, n=8), a neurotoxin that depleted ~70% of catecholamine (C1) neurons in the RVLM compared to IgG-saporin control (n=5). Low intensity SN stimulation evoked biphasic responses in the renal, splanchnic and lumbar nerves but a single peak in the cervical nerve. High intensity SN stimulation evoked triphasic responses in the renal, splanchnic and lumbar nerves and a biphasic cervical response. RVLM injections of SST abolished the early peak of the cervical and splanchnic SSR. Intraspinal pretreatment with anti-DβH-SAP eliminated the late peak of the splanchnic SSR and attenuated the first peak. It is concluded that the mono- or bi-phasic SSR responses are generated by A-fibre afferent inputs driving two classes of bulbospinal sympathoexcitatory RVLM neurons with myelinated or unmyelinated axonal conduction. Secondly, unmyelinated RVLM presympathetic neurons, presumed to be all C1, innervate splanchnic, renal and lumbar SPN, whereas myelinated C1 and non-C1 neurons innervate all sympathetic outflow examined. These findings extend prior evidence that the RVLM expresses several types of phenotypically distinct descending sympathoexcitatory pathways.

Related Products: Anti-DBH-SAP (Cat. #IT-03), Mouse IgG-SAP (Cat. #IT-18)

Hindbrain catecholamine neurons are required for rapid switching of metabolic substrate utilization during glucoprivation

Li A-J, Wang Q, Dinh TT, Ritter S (2010) Hindbrain catecholamine neurons are required for rapid switching of metabolic substrate utilization during glucoprivation. Neuroscience 2010 Abstracts 392.14/III1. Society for Neuroscience, San Diego, CA.

Summary: Glucoprivation is a metabolic emergency in which a rapid and effective system-wide switch to fat metabolism must occur to conserve any available glucose for use by the brain. Glucoprivation stimulates secretion of corticosterone, which is known to play an important role in promoting fat utilization. In previously published work, we showed that injections of the retrogradely transported catecholamine neuron immunotoxin, anti-dopamine beta-hydroxylase conjugated to saporin (DSAP) into the paraventricular nucleus of the hypothalamus (PVH) eliminate the corticosterone response to glucoprivation without impairing the response to a nonmetabolic stressor (swim stress), without altering the circadian rhythm of corticosterone secretion and without damaging the PVH CRF-secreting neurons. Here we microinjected DSAP into the PVH to selectively lesion hindbrain catecholamine neurons innervating this site, thus impairing the glucoprivation-induced corticosterone response. Using indirect calorimetry, we examined metabolic fuel utilization and other metabolic parameters in these lesioned rats under basal and glucoprivic conditions. Under basal conditions, energy expenditure and locomotor activity did not differ between DSAP rats and controls injected with unconjugated saporin (SAP). However, DSAP rats had a higher respiratory exchange ratio (RER) than SAPs, indicating their greater dependence on carbohydrate utilization. Glucoprivation induced by 2-deoxy-D-glucose (2DG, 250 mg/kg) reduced energy expenditure equally in SAP and DSAP rats. However, 2DG rapidly decreased RER to 0.8 (a value indicating ongoing fat metabolism) in the SAP group, but not in the DSAP group. Responses to 2DG persisted for about 6 hours. Adrenal dennervation, which eliminates the adrenal medullary response to glucoprivation, did not alter these responses to 2DG in either SAP or DSAP rats. Results indicate that in the absence of hypothalamically-projecting hindbrain catecholamine neurons, rats cannot efficiently switch their fuel utilization from carbohydrate to fat during glucoprivation, presumably due to a deficient corticosterone response. Results also suggest a previously unrecognized role for these catecholamine neurons in control of basal substrate utilization.

Related Products: Anti-DBH-SAP (Cat. #IT-03)

Time- and dose-response of 6-hydroxydopamine on locus coeruleus noradrenegric neurons in c57bl/6 mice

Szot P, Franklin A, White S, Raskind M (2010) Time- and dose-response of 6-hydroxydopamine on locus coeruleus noradrenegric neurons in c57bl/6 mice. Neuroscience 2010 Abstracts 157.20/R1. Society for Neuroscience, San Diego, CA.

Summary: Locus coeruleus (LC) noradrenergic neurons are severely reduced in Alzheimer’s and Parkinson’s disease. However, it is unclear why these neurons are lost and the consequence of this loss on the progression and symptoms of these neurodegenerative disorders. Therefore, establishing an animal model of LC noradrenergic neuronal loss is critical in determining how the LC contributes to these disorders. The purpose of this study was to determine the dose- and time-response of noradrenergic neurotoxicity of 6-hydroydopamine (6OHDA) in adult male C57BL/6 mice. Our laboratory recently demonstrated that DSP4 does not result in a loss of LC noradrenergic neurons. Neurotoxicity of 6OHDA on LC noradrenergic neurons was determined by measuring tyrosine hydroxylase (TH) mRNA expression and TH-immunoreactivity (IR) in LC noradrenergic neurons. TH mRNA was quantitated using MCID (OD), while TH-IR was used to determine if protein levels reflected what was observed with mRNA. 6OHDA (20 µg/µl bilaterally) and dopamine beta-hydroxylase-saporin (DBH-saporin; 1 µg/µl bilaterally) were initially administered into the lateral ventricles (icv) and sacrificed 2 weeks later. 6OHDA reduced TH mRNA and -IR in both the dopaminergic neurons of the substantia nigra (SNpc) and ventral tegmental nucleus (VTA), and LC by -46%, -65% and -63%, respectively. DBH-saporin icv injection did not affect dopaminergic or noradrenergic neurons. Injection of DBH-saporin into the LC (0.1 µg/µl unilaterally) also did not affect LC noradrenergic neurons 2 weeks later. As a time-course 6OHDA (7 µg/µl) was injected unilaterally into the LC (vehicle was administered in the alternate LC) and sacrificed 3 days, 2 and 3 weeks later. A loss of LC noradrenergic neurons was observed only 3 weeks later (-81.4%). 6OHDA was then injected unilaterally into the LC at 7, 10, and 14 ug/ul (vehicle was administered in the alternate LC) and sacrificed 2 weeks later. The 7 µg/µl dose of 6OHDA did not affect TH mRNA in the LC as compared to control side (-19%), 10 ug/ul 6OHDA significantly reduced TH mRNA in the LC by ~55%, and 14 ug/ul 6OHDA dramatically reduced TH mRNA in the LC by ~90%. TH-IR in the LC of the three different 6OHDA doses reflected closely the TH mRNA data. 6OHDA at the dose of 14 µg/µl, which resulted in a near complete loss of LC noradrenergic neurons, did not affect dopaminergic neurons in the SN (-9%) and VTA (+17%). These data indicate that DBH-saporin, at the parameters studied, did not affect mouse LC noradrenergic neurons. 6OHDA demonstrated a time- and dose-response reduction of mouse LC noradrenergic neurons. The consequence of this LC neuronal loss on forebrain noradrenergic markers will also be presented.

Related Products: Anti-DBH-SAP (Cat. #IT-03)

Locus ceruleus and anterior cingulate cortex sustain wakefulness in a novel environment.

Gompf HS, Mathai C, Fuller PM, Wood DA, Pedersen NP, Saper CB, Lu J (2010) Locus ceruleus and anterior cingulate cortex sustain wakefulness in a novel environment. J Neurosci 30(43):14543-14551. doi: 10.1523/JNEUROSCI.3037-10.2010

Objective: To examine arousal due to environmental stimuli after lesioning of the Locus ceruleus (LC).

Summary: Lesioned animals did not show sustained neurobehavioral and EEG arousal in response to a novel environment. The data suggest sustained attention requires an interaction between the LC and the anterior cingulate cortex.

Usage: Anti-DBH-SAP (0.25-1 µg) was injected into the lateral ventricle of rats.

Related Products: Anti-DBH-SAP (Cat. #IT-03)

Noradrenergic nuclei that receive sensory input during mating and project to the ventromedial hypothalamus play a role in mating-induced pseudopregnancy in the female rat.

Northrop LE, Polston EK, Erskine MS (2010) Noradrenergic nuclei that receive sensory input during mating and project to the ventromedial hypothalamus play a role in mating-induced pseudopregnancy in the female rat. J Neuroendocrinol 22(10):1061-1071. doi: 10.1111/j.1365-2826.2010.02049.x

Summary: Maintenance of pregnancy or pseudopregnancy in rats is maintained by bicircadian prolactin surges induced by vaginal-cervical stimulation. In order to test the hypothesis that medullary noradrenergic cell groups are involved in this process the authors infused rats with either 2 ng or 60 ng anti-DBH-SAP (Cat. #IT-03) into the ventrolateral division of the ventromedial hypothalamus (VMHv1) and the posterodorsal medial amygdala. Mouse IgG-Sap (Cat. #IT-18) was used as a control. The data confirm that noradrenergic neurons are involved in the maintenance of pregnancy or pseudopregnancy.

Related Products: Anti-DBH-SAP (Cat. #IT-03), Mouse IgG-SAP (Cat. #IT-18)

Contribution of limbic norepinephrine to cannabinoid-induced aversion.

Carvalho AF, Reyes AR, Sterling RC, Unterwald E, Van Bockstaele EJ (2010) Contribution of limbic norepinephrine to cannabinoid-induced aversion. Psychopharmacology (Berl) 211(4):479-491. doi: 10.1007/s00213-010-1923-7

Summary: The authors used bilateral injections of anti-DBH-SAP (Cat. #IT-03) into the nucleus accumbens and the bed nucleus of the stria terminalis to investigate the role of neuroepinephrine in cannabinoid-induced aversion and anxiety. Lesioned animals received bilateral 52.5 ng-injections of anti-DBH-SAP into the nucleus accumbens or 63 ng into the bed nucleus of the stria terminalis. Saporin (Cat. #PR-01) was used as a control. Lesioned animals displayed reversed aversive behavior, but no change in anxiety-like behavior.

Related Products: Anti-DBH-SAP (Cat. #IT-03), Saporin (Cat. #PR-01)

Noradrenergic neurons of the area postrema mediate amylin’s hypophagic action.

Potes CS, Turek VF, Cole RL, Vu C, Roland BL, Roth JD, Riediger T, Lutz TA (2010) Noradrenergic neurons of the area postrema mediate amylin's hypophagic action. Am J Physiol Regul Integr Comp Physiol 299(2):R623-631. doi: 10.1152/ajpregu.00791.2009

Summary: Amylin decreases food intake in rats and is a satiation signal affecting the area postrema (AP). This work investigated the role of noradrenergic neurons in amylin activity. Rats received a total of 50 ng of anti-DBH-SAP (Cat. #IT-03) into the AP and 25 ng into the lateral parabrachial nucleus. Mouse IgG-SAP (Cat. #IT-18) was used as a control. Rats showing a >50% lesion of noradrenergic neurons were unresponsive to low doses of amylin, suggesting that noradrenergic neurons are part of the amylin pathway.

Related Products: Anti-DBH-SAP (Cat. #IT-03), Mouse IgG-SAP (Cat. #IT-18)

Splanchnic sympathectomy prevents translocation and spreading of E coli but not S aureus in liver cirrhosis.

Worlicek M, Knebel K, Linde HJ, Moleda L, Scholmerich J, Straub RH, Wiest R (2010) Splanchnic sympathectomy prevents translocation and spreading of E coli but not S aureus in liver cirrhosis. Gut 59(8):1127-1134. doi: 10.1136/gut.2009.185413

Summary: Advanced cirrhosis activates the sympathetic nervous system. This work investigates the role of the sympathetic nervous system (SNS) in spontaneous bacterial peritonitis – which is mainly caused by translocation of enteric Gram-negative bacteria. Rats received 15 µg intraperitoneal injections of anti-DBH-SAP (Cat. #IT-03). Lesioned animals displayed increased susceptibility to bacterial translocation and infection with E. coli but not S. aureus. This suggests the SNS plays an important role in the immune response to Gram-negative bacteria.

Related Products: Anti-DBH-SAP (Cat. #IT-03)

Hindbrain catecholamine neurons modulate the growth hormone but not the feeding response to ghrelin.

Emanuel AJ, Ritter S (2010) Hindbrain catecholamine neurons modulate the growth hormone but not the feeding response to ghrelin. Endocrinology 151(7):3237-3246. doi: 10.1210/en.2010-0219

Summary: In this work the authors investigated the role of hindbrain catecholamine neurons in the response to a gastrointestinal peptide, ghrelin. Rats received 42 ng injections of anti-DBH-SAP (Cat. #IT-03) into the paraventricular nucleus of the hypothalamus. Saporin (Cat. #PR-01) was used as a control. Lesioned animals had a prolonged growth hormone (GH) response to ghrelin administration as compared to controls, but the feeding response was unchanged. The results indicate that ghrelin or GH may be involved with a negative feedback response controlling GH levels.

Related Products: Anti-DBH-SAP (Cat. #IT-03), Saporin (Cat. #PR-01)

Selective lesion of the developing central noradrenergic system: Short- and long-term effects and reinnervation by noradrenergic-rich tissue grafts.

Coradazzi M, Gulino R, Garozzo S, Leanza G (2010) Selective lesion of the developing central noradrenergic system: Short- and long-term effects and reinnervation by noradrenergic-rich tissue grafts. J Neurochem 114(3):761-771. doi: 10.1111/j.1471-4159.2010.06800.x

Summary: The authors removed noradrenergic neurons in the locus coeruleus/subcoeruleus complex of neonatal rats with 0.25-1.0 µg bilateral injections of anti-DBH-SAP (Cat. #IT-03). No damage was seen in dopaminergic, adrenergic, serotonergic, or cholinergic neurons after this treatment. Rats receiving fetal locus coeruleus tissue implants showed significant post-lesion recovery suggesting that this model can be used to investigate compensatory reinnervation and functional recovery in the central nervous system.

Related Products: Anti-DBH-SAP (Cat. #IT-03)

The hyperalgesic effects induced by the injection of angiotensin II into the caudal ventrolateral medulla are mediated by the pontine A(5) noradrenergic cell group.

Marques-Lopes J, Pinho D, Albino-Teixeira A, Tavares I (2010) The hyperalgesic effects induced by the injection of angiotensin II into the caudal ventrolateral medulla are mediated by the pontine A(5) noradrenergic cell group. Brain Res 1325:41-52. doi: 10.1016/j.brainres.2010.02.043

Summary: Injection of angiotensin II into the caudal ventrolateral medulla (CVLM) has been shown to induce angiotensin type 1 receptor-mediated hyperalgesia. Here the authors lesioned the pontine A5 cell group with anti-DBH-SAP (Cat. #IT-03) to evaluate the role of these neurons in this model. Rats received a 1.1 µg injection of anti-DBH-SAP into the CVLM. Behavioral responses indicate that loss of noradrenergic neurons in the CVLM partially prevented angiotensin II-induced hyperalgesia.

Related Products: Anti-DBH-SAP (Cat. #IT-03)

Cardiovascular and behavioural responses to conditioned fear and restraint are not affected by retrograde lesions of A5 and C1 bulbospinal neurons.

Vianna DM, Carrive P (2010) Cardiovascular and behavioural responses to conditioned fear and restraint are not affected by retrograde lesions of A5 and C1 bulbospinal neurons. Neuroscience 166:1210-1218. doi: 10.1016/j.neuroscience.2010.01.039

Summary: To investigate the role of A5 neurons in some forms of psychological stress the authors injected 22 or 44 ng of anti-DBH-SAP (Cat. #IT-03) into the spinal cord of rats. Mouse IgG-SAP (Cat. #IT-18) was used as a control. The data shows that A5 presympathetic neurons are not essential for the expression of the tachycardic and pressor responses to conditioned fear and restraint.

Related Products: Anti-DBH-SAP (Cat. #IT-03), Mouse IgG-SAP (Cat. #IT-18)

The brainstem noradrenergic systems in stress, anxiety, and depression.

Itoi K, Sugimoto N (2010) The brainstem noradrenergic systems in stress, anxiety, and depression. J Neuroendocrinol 22(5):355-361. doi: 10.1111/j.1365-2826.2010.01988.x

Summary: In this review the authors examine the relationship between the central noradrenergic system, fear/anxiety states, and depression. The use of anti-DBH-SAP (Cat. #IT-03) to investigate the function of the noradrenergic system in these paradigms is described.

Related Products: Anti-DBH-SAP (Cat. #IT-03)

Role of brainstem noradrenergic neurons in modulation of operant nocifensive responses to heat: Pharmacology and hyperalgesia.

Chatterjee K, Kline IV RH, Wiley RG (2009) Role of brainstem noradrenergic neurons in modulation of operant nocifensive responses to heat: Pharmacology and hyperalgesia. Neuroscience 2009 Abstracts 855.10/X15. Society for Neuroscience, Chicago, IL.

Summary: Many spinal dorsal horn neurons are under direct modulation from various brainstem nuclei which act to modulate nociceptive activity. Nocifensive reflex response modulation by spinally projecting noradrenergic brainstem nuclei has been extensively categorized. Strong evidence supports a role for these neurons in the modulation of reflex nocifensive responses but the role of noradrenergic neurons in the cerebral component of nociception remains to be defined in rats. In the present study, we sought to determine the effects of selectively destroying noradrenergic rostral brainstem neurons (A5,A6,A7) on operant escape from 44°C floor heat under several conditions: 1-baseline (after i.c.v. toxin/vehicle injection), 2- after s.c. injection of morphine, clonidine or yohimbine, 3- three hours after bilateral dorsal hindpaw application of mustard oil (secondary hyperalgesia), and 3- three hours after bilateral plantar application of 0.9% capsaicin cream (primary hyperalgesia). Rats were tested daily until steady operant escape responding (~1 month), then injected i.c.v. with 10µl of PBS (vehicle control, n=8) or antiDBH-saporin (10µg, n=8). After recovery from toxin injection, escape responses decreased in the antiDBH-sap rats. Morphine (0, 0.5, 1.0, 2.0 mg/kg s.c.) 20 min prior to testing, dose dependently attenuated escape from the noxious thermal plate at 44oC for all treatment groups. antiDBH-sap treated rats, however, showed an enhanced morphine effect (more prolonged occupancy of the noxious thermal plate). Three hours after plantar capsaicin, or mustard oil to the dorsal surface of both hindpaws, PBS but not antiDBH-sap rats showed enhanced escape. Systemic clonidine (0.125mg/kg) decreased escape for both PBS and antiDBH-sap treated rats, but the anti-nociceptive effect was greater in antiDBH-sap rats. Systemic yohimbine (1.0, 2.5, 5.0mg/kg) had no effect on escape in antiDBH-sap rats but enhanced escape in PBS rats. In direct contrast to effects on escape responding, antiDBH-sap did not affect hotplate lick/guard initial latencies to nociceptive heat at 44° or 47oC. Escape responses to aversively bright light were also decreased in antiDBH-sap rats suggesting generally decreased responsiveness to aversive stimuli. These results support a significant role for rostral brainstem noradrenergic neurons in modulation of pain and highlight important differences between reflex nocifensive responses (hotplate) and operant (escape) responses.

Related Products: Anti-DBH-SAP (Cat. #IT-03)

Immunotoxic lesion of hypothalamic noradrenergic/adrenergic input ameliorates the effects of peripheral LPS challenge on sickness behavior and associated brain c-Fos expression

Gaykema RP, Thacker GC, Shapiro NJ, Goehler LE (2009) Immunotoxic lesion of hypothalamic noradrenergic/adrenergic input ameliorates the effects of peripheral LPS challenge on sickness behavior and associated brain c-Fos expression. Neuroscience 2009 Abstracts 570.11/EE120. Society for Neuroscience, Chicago, IL.

Summary: Caudal medullary catecholamine neurons that innervate the hypothalamus play a major role in the activation of paraventricular neurons that drive pituitary adrenocorticotropin and adrenal corticosteroid release in response to peripheral pro-inflammatory challenges with interleukin-1 or lipopolysaccharide (LPS). Pro-inflammatory challenges also lead to marked behavioral changes, including fatigue, loss of social interest, anorexia, somnolence, but the precise neuronal mechanisms that underlie sickness behavior remain elusive. We reasoned that the medulla-hypothalamic catecholaminergic pathway may also contribute to the behavioral manifestations in illness. To investigate such possible role, we applied a targeted lesion approach in rats to determine whether or not caudal brainstem catecholaminergic neurons that innervate the hypothalamus are also necessary for the expression of sickness behavior. Anti-dopamine beta hydroxylase antibodies conjugated to saporin (DSAP), when injected into a target region, selectively poisons and destroy noradrenergic/adrenergic neurons that innervate the target. DSAP was micro-injected bilaterally into the hypothalamic paraventricular nucleus (PVN), whereas control rats received unconjugated saporin (SAP controls). Fourteen days later the animals were injected intraperitoneally with either LPS or saline, and 2h later were submitted to the open field to record their exploratory behavior, 1h after which the rats were sacrificed for brain immunohistochemical analyses. LPS-treated SAP control rats showed drastic reduction in exploratory behavior (reduced locomotion distance and velocity). Prior DSAP microinjections largely reversed the LPS-induced reduction in locomotor behavior. The brains of these DSAP rats showed a dramatic loss of noradrenergic innervation of the PVN but also in other parts of the medial, tuberal and tuberomammilary regions of the hypothalamus. The behavioral resilience to LPS coincided with diminished LPS-related c-Fos staining in the PVN, and increased c-Fos staining in the lateral and tuberomammillary regions related to behavior and/or arousal. In summary, our findings support the hypothesis that hypothalamic catecholaminergic projections originating in the lower brainstem play a critical role in the expression of sickness behavior in the context of novelty-induced exploratory activity, but we cannot determine with precision in which part of the hypothalamus the noradrenergic/adrenergic input contributes to the expression of sickness behavior due to extensive collateralization of the ascending projections throughout the hypothalamus.

Related Products: Anti-DBH-SAP (Cat. #IT-03)

The role of limbic norepinephrine in cannabinoid-induced aversion.

Carvalho AF, Reyes AS, Van Bockstaele EJ (2009) The role of limbic norepinephrine in cannabinoid-induced aversion. Neuroscience 2009 Abstracts 449.3/V29. Society for Neuroscience, Chicago, IL.

Summary: The endocannabinoid system has been implicated in diverse physiological mechanisms including modulation of pain and analgesia, learning and memory and feeding, among others. Thus, targeting the cannabinoid system has risen to the forefront in the development of novel treatments for a number of pathophysiological processes. Consistent with this, agonists of the cannabinoid receptor type 1 (CB1R) have been successfully used in the treatment of severe anorexia in patients with AIDS and in alleviating nausea and vomiting in patients undergoing chemotherapy. However, significant side effects have been observed in clinical trials raising concerns regarding the potential clinical utility of cannabinoid-based agents. Disturbances in mood and affect, including paranoia, anxiety and nervousness, have been reported in patients. Understanding the neural circuits and neurochemical substrates impacted by cannabinoids will provide a better means of gauging their actions within the central nervous system that contribute to the expression of unwanted side effects. We have previously shown an increase in anxiety-like behaviors in rats receiving repeated administration of cannabinoid agonists. This increase in anxiety was accompanied by increases in indices of noradrenergic activity. In the present study, we investigated whether norepinephrine in the limbic forebrain of rats is required for cannabinoid-induced aversion using an immunotoxin lesion approach combined with behavioral analysis using a place conditioning paradigm. Male Sprague Dawley rats received bilateral injections of a ribosomal toxin, saporin (SAP) conjugated to an antibody that specifically recognizes the enzyme dopamine-beta-hydroxylase (DSAP), into the limbic forebrain. Control rats received saporin alone. As previously reported, administration of the synthetic cannabinoid receptor agonist, WIN 55,212-2 (3.0mg/kg), induced aversion in a place conditioning paradigm in SAP-only treated rats. The rats’ spatial memory was also evaluated using the Morris Water Maze. Depletion of norepinephrine using DSAP in specific limbic regions impaired cannabinoid-induced aversion to WIN 55,212-2 without affecting learning and memory processes. Taken together, noradrenergic projections to the limbic forebrain may be critical in the manifestation of aversive behaviors associated with cannabinoid agonist exposure.

Related Products: Anti-DBH-SAP (Cat. #IT-03)

Role of A2 noradrenergic neurons and angiotensinergic mechanisms on hypotension induced by hemorrhage.

Freiria-Oliveira AH, Blanch GT, De Paula PM, Colombari E, Menani JV, Colombari DS (2009) Role of A2 noradrenergic neurons and angiotensinergic mechanisms on hypotension induced by hemorrhage. Neuroscience 2009 Abstracts 467.18/DD70. Society for Neuroscience, Chicago, IL.

Summary: The A2 catecholaminergic neurons in the commissural subdivision of the nucleus tractus solitarii (cNTS) are activated by hemorrhage. However, the role of these neurons on the cardiovascular adjustments to hemorrhage is not fully understood. In the present study we investigated the effects of A2 noradrenergic neuron lesion alone or combined with the blockade of angiotensinergic mechanisms on the recovery of blood pressure after hemorrhage. Male Holtzman rats (280-320 g) anesthetized with ketamine combined with xylazine were submitted to lesions of dopamine-beta-hydroxilase (DβH)-containing neurons in the cNTS achieved with injections of anti-DβH-saporin (12.6 ng/60 nl, n=6-8) or sham lesions (injection of immunoglobulin-G-saporin, 12.6 ng/60 nl, n=6). Changes in blood pressure to hemorrhage were tested 30 days after lesions. Immunohistochemistry for tyrosine-hydroxilase was performed to confirm the efficacy of DβH neuron lesion in the cNTS. Two days before tests, femoral artery and vein were cannulated under ketamine and xylazine anesthesia. Hemorrhage consisted in four blood withdrawals (2 ml/300 g body weight, every 10 min) in conscious rats. Immediately after the 4th blood withdrawal, the hypotension was similar in A2-lesioned and sham-lesioned rats (-62 ± 7 mmHg and -73±7 mmHg, respectively). However, A2-lesioned rats rapidly (20 min) recovered from hypotension (-7±2 mmHg), while sham rats did not completely recover from hypotension until the end of experiment (60 min after the 4th blood withdrawn, -20±3 mmHg). The pre-treatment with losartan (angiotensin type 1 receptor antagonist, 10 mg/kg of body weight, iv) impaired the recovery of blood pressure by A2-lesioned rats (-29 ± 4 mmHg and -28 ± 3 mmHg, 20 and 60 min after the 4th blood withdrawal). In sham rats, the treatment with losartan also reduced the partial recovery of blood pressure at the end of the test (-39±6 mmHg, vs. sham control: -20±3mmHg), however, losartan did not affect the hypotension 20 min after the 4th blood withdrawal (-30± 6 mmHg vs. sham control: -35 ± 9 mmHg). The results suggest that A2 noradrenergic neuron lesion in the cNTS facilitates the recovery of hypotension after hemorrhage, probably increasing the action of angiotensinergic mechanisms.

Related Products: Anti-DBH-SAP (Cat. #IT-03)

Caudal hindbrain catecholaminergic projection to the ventrolateral bed nucleus of the stria terminalis (vlBNST): Assessment of role in glucoprivic and CCK feeding responses and corticosterone secretion.

Dinh TT, Huston NJ, Ritter S (2009) Caudal hindbrain catecholaminergic projection to the ventrolateral bed nucleus of the stria terminalis (vlBNST): Assessment of role in glucoprivic and CCK feeding responses and corticosterone secretion. Neuroscience 2009 Abstracts 87.16/CC80. Society for Neuroscience, Chicago, IL.

Summary: Catecholamine neurons in the caudal hindbrain provide a significant innervation of the vlBNST and some of these neurons co-innervate the paraventricular nucleus of the hypothalamus (PVH). We previously found that PVH injections of the retrogradely-transported immunotoxin, anti-dopamine beta hydroxylase (DBH) saporin (anti-DBH-sap), profoundly reduced feeding and corticosterone responses to glucoprivation, but did not alter CCK-induced satiety, which has been linked to catecholamine neurons in the A2 cell group. In this experiment, we examined the origin of the vlBNST/PVH catecholamine projection and assessed its role in responses to glucoprivation and CCK. Retrograde tracing from vlBNST and PVH revealed dually-projecting DBH-ir (norepinephrine or epinephrine) neurons primarily in A2, A1 and caudal C1, with a few cells also present in C2. Dually-projecting PNMT-ir (epinephrine) were also present in C1 and in small numbers in C2. Overall, the relative numbers of DBH- and PMNT-ir neurons with projections to both vlBNST and PVH and the locations of these triply-labeled neurons indicate that the dually-projecting neurons are predominantly noradrenergic. Injections of anti-DBH-sap into the vlBNST produced cell losses in the hindbrain that were anatomically consistent in distribution and number with the tracing results. This immunotoxin caused a loss of DBH neurons in the dorsal hindbrain that was concentrated in the A2 cell group (14.6 - 13.68 mm caudal to bregma), where a maximum of 50% of DBH neurons were lesioned: 50% loss at 14.6 mm caudal to bregma, 25% at 13.24 mm and 0% at 11.96 mm. In ventral hindbrain, loss of DBH cell bodies was predominantly in the A1 cell group (14.6 - 12.8 mm caudal to bregma), where a maximum of 60% of DBH-ir neurons were lesioned: 60% loss at 14.6 and 13.68 mm, 22% at 13.24 and and 0% at 12.8 mm. In the dorsal hindbrain nearly all cells retrogradely labeled from the vlBNST were ipsilateral and DBH-ir. In ventral hindbrain there was a significant contralateral projection to vlBNST that was not DBH-ir. Anti-DBH-sap lesions did not impair the feeding, blood glucose or corticosterone responses to 2-deoxy-D-glucose (250 mg/kg) and did not impair the suppression of feeding by CCK-8 (4 ug/kg), indicating that the catecholamine projection to the vlBNST, including the dually-projecting neurons that innervate both the vlBNST and the PVH, is not required for these responses.

Related Products: Anti-DBH-SAP (Cat. #IT-03)

Nitrous oxide-induced analgesia does not influence nitrous oxide’s immobilizing requirements.

Jinks SL, Carstens E, Antognini JF (2009) Nitrous oxide-induced analgesia does not influence nitrous oxide's immobilizing requirements. Anesth Analg 109:1111-1116. doi: 10.1213/ANE.0b013e3181b5a2a7

Summary: Noradrenergic neurons in the locus coeruleus (LC) are involved with the analgesic action of nitrous oxide (N2O). In order to examine whether these neurons are also involved with the immobilizing effects of N2O, rats received 4 µg intracerebroventricular injections of anti-DBH-SAP (Cat. #IT-03). Mouse IgG-SAP (Cat. #IT-18) was used as a control. Lesioned animals did not experience the analgesic effects of N2O, but the immobilizing effects were still present. The data demonstrate that the immobilizing mechanism of N2O is independent from its analgesic effects.

Related Products: Anti-DBH-SAP (Cat. #IT-03), Mouse IgG-SAP (Cat. #IT-18)

Photostimulation of retrotrapezoid nucleus phox2b-expressing neurons in vivo produces long-lasting activation of breathing in rats.

Abbott SB, Stornetta RL, Fortuna MG, Depuy SD, West GH, Harris TE, Guyenet PG (2009) Photostimulation of retrotrapezoid nucleus phox2b-expressing neurons in vivo produces long-lasting activation of breathing in rats. J Neurosci 29:5806-5819. doi: 10.1523/JNEUROSCI.1106-09.2009

Summary: The retrotrapezoid nucleus (RTN) contains a subpopulation of cells that are thought to function as central respiratory chemoreceptors. The authors used bilateral 22-ng injections of anti-DBH-SAP (Cat. #IT-03) into the lateral horn of the second thoracic segment to investigate this hypothesis. Coupled with data generated by lentivirus-driven transgenic expression of a light-activated cationic channel, it is demonstrated that noncatecholaminergic neurons in the RTN function as central respiratory chemoreceptors.

Related Products: Anti-DBH-SAP (Cat. #IT-03)

Noradrenergic neurons in the locus coeruleus contribute to neuropathic pain.

Brightwell JJ, Taylor BK (2009) Noradrenergic neurons in the locus coeruleus contribute to neuropathic pain. Neuroscience 160:174-185. doi: 10.1016/j.neuroscience.2009.02.023

Summary: Noradrenergic neurons were eliminated with 5 µg intracerebroventricular injections of anti-DBH-SAP (Cat. #IT-03). Mouse IgG-SAP (Cat. #IT-18) was used as a control. Animals lesioned with anti-DBH-SAP displayed a reduction in behavioral signs of several kinds of allodynia.

Related Products: Anti-DBH-SAP (Cat. #IT-03), Mouse IgG-SAP (Cat. #IT-18)

Recent progress in research on ribosome inactivating proteins.

Ng TB, Wong JH, Wang H (2009) Recent progress in research on ribosome inactivating proteins. Curr Protein Pept Sci 1323:94-108. doi: 10.2174/138920310790274662

Summary: This review discusses recent literature on ribosome inactivating proteins including the use of saporin-based conjugates in neuroscience and cancer research. Brief descriptions of research done using 192-IgG-SAP (Cat. #IT-01), OX7-SAP (Cat. #IT-02), dermorphin-SAP (Cat. #IT-12), anti-SERT-SAP (Cat. #IT-23), SSP-SAP (Cat. #IT-11), anti-DBH-SAP (Cat. #IT-03), CTB-SAP (Cat. #IT-14), and other conjugates are provided along with basic information about ribosome inactivating proteins.

Related Products: 192-IgG-SAP (Cat. #IT-01), OX7-SAP (Cat. #IT-02), Dermorphin-SAP / MOR-SAP (Cat. #IT-12), Anti-SERT-SAP (Cat. #IT-23), SSP-SAP (Cat. #IT-11), Anti-DBH-SAP (Cat. #IT-03), CTB-SAP (Cat. #IT-14)

Methylphenidate-induced impulsivity: pharmacological antagonism by beta-adrenoreceptor blockade.

Milstein JA, Dalley JW, Robbins TW (2010) Methylphenidate-induced impulsivity: pharmacological antagonism by beta-adrenoreceptor blockade. J Psychopharmacol 24:309-321. doi: 10.1177/0269881108098146

Summary: In this work bilateral 20 ng intracortical injections of anti-DBH-SAP (Cat. #IT-03) were used to examine the role of noradrenergic neurons in the control of psychostimulant-induced impulsivity. Although β-adrenoreceptor blockade abolished this impulsivity, lesioning noradrenergic neurons in the cortex had no effect. The data indicate that modulation of impulsive responding in this model is controlled by β-adrenoreceptors.

Related Products: Anti-DBH-SAP (Cat. #IT-03)

Effect of noradrenergic denervation on cerebral cortex catecholamines in the rat

Flore G, Saba P, Paba S, Gessa G, Pistis M, Devoto P (2008) Effect of noradrenergic denervation on cerebral cortex catecholamines in the rat. Neuroscience 2008 Abstracts 726.3/D6. Society for Neuroscience, Washington, DC.

Summary: Previous studies in rats have indicated that extracellular dopamine (DA) content in cortical areas with scarce or undetectable dopaminergic innervation, such as the occipital (Occ) or parietal cortex, is modestly lower than that present in areas densely innervated such as the medial prefrontal (mPF) cortex, suggesting that extracellular DA may originate, other than from dopaminergic, also from the homogeneously and densely distributed noradrenergic terminals. To further verify such hypothesis cortical noradrenergic neurons were lesioned with the intraventricular injection of the immunotoxin anti-DA-beta-hydroxylase saporin. Extracellular DA and noradrenaline (NA) were measured in the mPF and Occ cortices by microdialysis 15 to 18 days after the lesion when tissue NA content had been reduced by about 95%, with respect to control rats injected with PBS. The lesion reduced extracellular NA in both cortices, but increased extracellular DA in the mPF and Occ cortices. To verify if such increase was due to the impairment of DA uptake into NA terminals, the NA transporter was inhibited with nisoxetine (NIS). While in control rats NIS increased both extracellular NA and DA, in denervated rats it failed to modify extracellular NA and DA in either cortex, confirming that the NA transporter had been inactivated by the lesion. To verify if the lesion modified the output capacity of dopaminergic and noradrenergic neurons, the effect of the alpha2-adrenoreceptor blocker RS 79948 (RS), given alone or in combination with NIS, in control and denervated rats was compared. In control rats, RS increased extracellular NA and DA in both cortices; in combination with nisoxetine RS produced a striking more than tenfold increase in extracellular NA and DA. In lesioned rats RS increased DA levels, failed to modify extracellular NA, while its co-administration with NIS slightly increased NA output. However, after RS plus NIS, extracellular DA was increased by the same extent as after RS alone, indicating that denervation had severely impaired the capacity of neurons to increase DA output after alpha2-adrenoceptor block. The possibility that such neurons might correspond to NA neurons surviving the lesion is discussed.

Related Products: Anti-DBH-SAP (Cat. #IT-03)

Analysis of inhibitory phase of formalin test: Effects of specific neural lesions

Wiley RG, Moore SA, Kline IV RH (2008) Analysis of inhibitory phase of formalin test: Effects of specific neural lesions. Neuroscience 2008 Abstracts 772.4/MM19. Society for Neuroscience, Washington, DC.

Summary: The formalin test has been widely used as a model of persistent pain. The 90 mins of formalin-induced nocifensive responding can be divided into two phases (phase 1, first ~10 mins; phase 2, last ~60 mins) separated by a period of reduced responding (interphase, IP), that has received relatively little attention. Behavioral inhibition during the IP of the formalin test has been associated with electrophysiological evidence of inhibition of dorsal horn nociceptive neurons (Henry et al, Pain, 82:57, 1999), probably due, at least in part, to local spinal mechanisms. Behavioral inhibition during IP has been shown to be enhanced by morphine and suppressed by naloxone. In the present study, we sought to determine the effect of selective depletion of specific dorsal horn interneurons known to be involved in nociception, i.e. neurons expressing NPY1R, GalR1 or MOR, or selective destruction of cerebral noradrenergic neurons or spinal cord projecting 5-HT neurons on formalin-induced nociceptive behavior, with particular attention to IP. Type-selective lesions were produced by lumbar intrathecal injection of NPY-saporin, galanin-saporin or dermorphin-saporin, respectively. Cerebral noradrenergic neurons and spinally projecting 5-HT neurons were destroyed using the immunotoxins, antiDBH-saporin (intracerebroventricular) or antiSERT-saporin (lumbar intrathecal), respectively. Partial loss of dorsal horn interneurons expressing NPY1R or GalR1 decreased nocifensive responding during IP and phase 2 of the formalin test, while partial loss of MOR-expressing dorsal horn interneurons increased nocifensive responding during IP and during phase 2. Both antiDBH-sap and antiSERT-sap decreased responding during IP, without effects on either phase 1 or 2. These results suggest that the apparent anti-nociception during IP and phase 2 produced by loss of NPY1R- and GalR1-expressing dorsal horn neurons is due to increased inhibition over excitation/facilitation of nociceptive projection neurons, whereas depletion of MOR-expressing interneurons produces the opposite effect. The apparent enhanced nociception during IP, but not phase I and II, produced by antiDBH-sap and antiSERT-sap suggests that these neural systems serve to enhance the excitability of nociceptive projection neurons during the formalin IP. Electrophysiologic and pharmacologic studies of formalin IP in selectively lesioned animals combined with the above behavioral findings may reveal new insights into endogenous modulation of nocifensive motor responses and/or nociception.

Related Products: NPY-SAP (Cat. #IT-28), Anti-SERT-SAP (Cat. #IT-23), Galanin-SAP (Cat. #IT-34), Anti-DBH-SAP (Cat. #IT-03), Dermorphin-SAP / MOR-SAP (Cat. #IT-12)

Interactions between corticosterone and catecholaminergic afferents in the regulation of neuropeptide gene expression in neuroendocrine CRH neurons in the paraventricular nucleus of the hypothalamus

Rapp KL, Watts AG (2008) Interactions between corticosterone and catecholaminergic afferents in the regulation of neuropeptide gene expression in neuroendocrine CRH neurons in the paraventricular nucleus of the hypothalamus. Neuroscience 2008 Abstracts 782.2/RR7. Society for Neuroscience, Washington, DC.

Summary: Neurons in the medial parvicellular part of the paraventricular nucleus of the hypothalamus (PVH) are responsible for neuroendocrine activation of corticotropes in the anterior hypophysis. While corticotropin-releasing hormone (CRH) is the primary peptide responsible for synthesis and release of adrenocorticotropin hormone (ACTH), vasopressin (AVP) is also effective in stimulating ACTH, which stimulates synthesis & secretion of corticosterone (CORT) from the adrenal cortex. This descending pathway, the HPA axis, is part of the stress axis, as its output of CORT facilitates adaptation to changes in energy. While AVP is synthesized in both parvicellular and magnocellular populations of the PVH, it is the AVP in the parvicellular PVH that colocalizes with CRH and increases after adrenalectomy (ADX). The underlying mechanisms contributing to the CORT regulation of Crh and Avp expression still remain elusive, particularly with regard to the role of neural afferents. A major afferent projection system to the PVH originates from hindbrain catecholaminergic (CA) neuron subpopulations. Using saporin-anti-dopamine beta hydroxylase (DSAP) immunotoxin conjugate, to specifically eliminate CA afferents has revealed the importance of CA projections to PVH for both increased Crh expression, and elevated levels of circulating ACTH & CORT following glycemic challenges. We utilized DSAP-mediated deafferentation, followed by ADX and CORT replacement, to determine the role of CA afferents in mediating effects of circulating CORT on Crh and Avp regulation. Male Sprague Dawley rats (~315g) received acute bilateral microinjections of DSAP stereotaxically delivered into the PVH. A control group received bilateral microinjections of saporin conjugated to a non-targeting mouse IgG (SAP). One week later, rats received ADX and timed-release CORT pellet implants (25, 50 or 100 mg). Seven days post-ADX, rats were killed, and radioimmunoassay of plasma from terminal blood samples revealed significantly higher CORT levels in DSAP- vs. SAP-treated rats in CORT replaced groups: 25 mg (p < 0.001), 50 mg (p < 0.01). In contrast, in situ hybridization revealed significantly increased CRH mRNA levels (p < 0.001) and AVP hnRNA levels (p < 0.02) in DSAP- vs. SAP-treated rats with comparable plasma CORT levels. These results suggest that loss of hindbrain CA afferents contributes to the ability of circulating CORT to regulate Crh and Avp expression. The data implicate synergistic interactions between CORT & PVH neural afferents that provide critical metabolic information from the periphery in the regulation of CRH neuroendocrine neurons. Supported by NINDS. (NS029728)

Related Products: Anti-DBH-SAP (Cat. #IT-03)

Stimulus-, circuit- and intracellular-level determinants of MAP kinase and CREB activation in parvicellular hypothalamic paraventricular neurons

Khan AM, Rapp KL, Ponzio TA, Sanchez-Watts G, Watts AG (2008) Stimulus-, circuit- and intracellular-level determinants of MAP kinase and CREB activation in parvicellular hypothalamic paraventricular neurons. Neuroscience 2008 Abstracts 865.23/MM24. Society for Neuroscience, Washington, DC.

Summary: Systemic insulin or 2-deoxyglucose (2-DG) rapidly elevate phosphorylated MAP kinases (phospho-ERK1/2) and/or CRH hnRNA in PVHp neurons, and increase circulating ACTH and corticosterone. These neuroendocrine responses are likely driven by hindbrain-originating catecholaminergic (CA) neuron subpopulations, which richly innervate the PVHp and are activated by glycemic challenges. Supporting this, acute in vivo or in vitro PVH delivery of the prototypical catecholamine, norepinephrine (NE), recapitulates these responses (J Neurosci, 2007, 27:7344-7360). Here, we determined whether PVHp ERK/CREB phosphorylation responses require: 1) intact CA afferents, when triggered by three distinct in vivo challenges; and 2) upstream MEK kinase activity, when triggered by NE application in acute hypothalamic slices maintained in vitro. Methods. Rats given PVH microinjections of anti-dopamine-b-hydroxylase (DBH)-saporin antibody-toxin conjugate (DSAP) or mIgG-saporin control conjugate received either normal 0.9% saline vehicle or one of three systemic challenges: insulin (2 U/kg, i.v.); 2-DG (250 mg/kg, i.v.); or hypertonic saline (1.5 M, i.p.) and sacrificed 30 min later. Brains were processed for CRH mRNA/hnRNA hybridization, or DBH, phospho-ERK or phospho-CREB immunocytochemistry. Plasma was collected for hormone determinations at 0 and 30 min. In separate in vitro studies, acute hypothalamic slices received either no treatment (controls), or received bath-applied NE (100 mM) in the presence or absence of the MEK inhibitor, U0126 (10 mM), or the inactive MEK inhibitor analogue, U0124 (10 mM). Ten min later, slices were placed in fixative. Results. 1. Sham-lesioned animals: Relative to vehicle, all challenges elevated phospho-ERK1/2, phospho-CREB, and ACTH/corticosterone levels; and, except for insulin, also increased CRH hnRNA. 2. Lesioned animals: DSAP treatment selectively destroyed hindbrain-originating CA afferents. In insulin- and, to a lesser extent, 2-DG-treated animals, this loss was accompanied by markedly reduced PVH phospho-ERK1/2 and circulating ACTH/corticosterone. In contrast, these responses remained robust in CA-deafferented hypertonic saline-treated rats. Phospho-CREB levels were differentially reduced relative to phospho-ERK in lesioned rats. 3. Slices: NE-induced PVH elevations of phosphorylated ERK1/2 and CREB were reduced markedly by U0126, but not U0124, pre-treatment. Conclusions. PVHp phospho-ERK selectively couples to CA afferents during glycemic challenges and ERK/CREB recruitment appears to require MEK activity.

Related Products: Anti-DBH-SAP (Cat. #IT-03)

ATS Poster of the Year Winner. Read the featured article in Targeting Trends.

Renal sympathoinhibition induced by hypernatremia: Involvement of A1 noradrenergic neurons.

Pedrino GR, Rosa DA, Korim WS, Cravo SL (2008) Renal sympathoinhibition induced by hypernatremia: Involvement of A1 noradrenergic neurons. Auton Neurosci 142(1-2):55-63. doi: 10.1016/j.autneu.2008.06.006

Summary: A1 noradrenergic neurons in the caudal ventrolateral medulla (CVLM) are thought to contribute to body fluid homeostasis and cardiovascular regulation. In order to examine the role these neurons play on inhibition of renal sympathetic nerve activity (RSNA) induced by hypertonic saline infusion, rats received 6.3 ng of anti-DBH-SAP (Cat. #IT-03) into the CVLM. Saporin (Cat. #PR-01) was used as a control. Animals treated with anti-DBH-SAP displayed lengthened duration of the pressor response and sustained RSNA.

Related Products: Anti-DBH-SAP (Cat. #IT-03), Saporin (Cat. #PR-01)

Noradrenergic inputs to the paraventricular hypothalamus contribute to hypothalamic-pituitary-adrenal axis and central Fos activation in rats after acute systemic endotoxin exposure.

Bienkowski MS, Rinaman L (2008) Noradrenergic inputs to the paraventricular hypothalamus contribute to hypothalamic-pituitary-adrenal axis and central Fos activation in rats after acute systemic endotoxin exposure. Neuroscience 156(4):1093-1102. doi: 10.1016/j.neuroscience.2008.08.011

Summary: Noradrenergic (NA) neurons in the central nervous system are activated during the immune response to systemic lipopolysaccharide (LPS). The authors tested whether these neurons with axonal inputs to the paraventricular nucleus (PVN) were necessary for LPS-directed Fos expression and increase of plasma corticosterone. Rats received 44-ng bilateral injections of anti-DBH-SAP (Cat. #IT-03) into the medial PVN then were challenged with i.p. LPS. Lesioned animals had attenuated Fos activation and smaller than normal increases in plasma corticosterone.

Related Products: Anti-DBH-SAP (Cat. #IT-03)

Lesions of medullary catecholaminergic neurons increase salt intake in rats.

Colombari DS, Pedrino GR, Freiria-Oliveira AH, Korim WS, Maurino IC, Cravo SL (2008) Lesions of medullary catecholaminergic neurons increase salt intake in rats. Brain Res Bull 76:572-578. doi: 10.1016/j.brainresbull.2008.04.001

Summary: Catecholaminergic neurons in the caudal ventrolateral medulla (CVLM) are thought to contribute to cardiovascular regulation and body fluid homeostasis. Bilateral 6.3-ng injections of anti-DBH-SAP (Cat. #IT-03) were administered to the CVLM of rats. Saporin (Cat. #PR-01) was used as a control. After lesioning and challenge with either furosemide/captopril or water deprivation, intake of 0.3 M NaCl and water were observed. The data indicate medullary catecholaminergic neurons play an inhibitory role in sodium appetite.

Related Products: Anti-DBH-SAP (Cat. #IT-03), Saporin (Cat. #PR-01)

An early sympathetic nervous system influence exacerbates collagen-induced arthritis via CD4+CD25+ cells.

Harle P, Pongratz G, Albrecht J, Tarner IH, Straub RH (2008) An early sympathetic nervous system influence exacerbates collagen-induced arthritis via CD4+CD25+ cells. Arthritis Rheum 58:2347-2355. doi: 10.1002/art.23628

Summary: The sympathetic nervous system can play conflicting roles in collagen-induced arthritis (CIA). CD4+CD25+ T cells can play an immunoregulatory effect in this system depending on the expression of the FoxP3 transcription factor. Mice received 5 µg intraperitoneal injections of anti-DBH-SAP (Cat. #IT-03) to induce an early sympathectomy. The results indicate that the sympathetic nervous system increases disease severity in CIA by stimulating some of the proinflammatory aspects of CD4+CD25+ T cells.

Related Products: Anti-DBH-SAP (Cat. #IT-03)

Noradrenergic innervation of the dorsal medial prefrontal cortex modulates hypothalamo-pituitary-adrenal responses to acute emotional stress.

Radley JJ, Williams B, Sawchenko PE (2008) Noradrenergic innervation of the dorsal medial prefrontal cortex modulates hypothalamo-pituitary-adrenal responses to acute emotional stress. J Neurosci 28:5806-5816. doi: 10.1523/JNEUROSCI.0552-08.2008

Summary: Hypothalamo-pituitary-adrenal (HPA) responses to emotional stress are in part controlled by the medial prefrontal cortex (mPFC). The locus ceruleus (LC) is also thought to be involved in this system, leading to the question of what interaction might exist between the mPFC and LC. Rats were injected with 90-120 nl of 0.475-µg/µl anti-DBH-SAP (Cat. #IT-03) into the cortical field containing noradrenergic neurons that project to the dorsal mPFC. The results indicate that the LC functions as an upstream component in mPFC modulation of HPA activation due to emotional stress.

Related Products: Anti-DBH-SAP (Cat. #IT-03)

Read the featured article in Targeting Trends.

Brainstem catecholaminergic neurons modulate both respiratory and cardiovascular function.

Li A, Emond L, Nattie E (2008) Brainstem catecholaminergic neurons modulate both respiratory and cardiovascular function. (eds. Poulin MJ, Wilson RJA). In: Integration in Respiratory Control. Advances in Experimental Medicine and Biology 605:371-376. Springer, New York, NY. doi: 10.1007/978-0-387-73693-8_65

Summary: The authors examined the role of brainstem catecholamine (CA) neurons in various aspects of breathing and chemoreception. Rats received 5-µg injections of anti-DBH-SAP (Cat. #IT-03) into the 4th ventricle; mouse IgG-SAP (Cat. #IT-18) was used as a control. This method of lesioning left the CA neurons in the peripheral nervous system intact. Lesioned animals displayed a constant decrease in breathing frequency, reduced response to CO2, and increased variability of breathing during REM sleep. Inhibitory cardiovascular effects were also seen.

Related Products: Anti-DBH-SAP (Cat. #IT-03), Mouse IgG-SAP (Cat. #IT-18)

Central chemoreception is a complex system function that involves multiple brain stem sites.

Nattie E, Li A (2009) Central chemoreception is a complex system function that involves multiple brain stem sites. J Appl Physiol 106:1464-1466. doi: 10.1152/japplphysiol.00112.2008

Summary: This short review discusses central chemoreception and the different neuronal subtypes that play roles in this process. The use of anti-SERT-SAP (Cat. #IT-23) and anti-DBH-SAP (Cat. #IT-03) is mentioned in the context of how the loss of each of these cell types affects CO2 response in rats.

Related Products: Anti-SERT-SAP (Cat. #IT-23), Anti-DBH-SAP (Cat. #IT-03)

Noradrenergic, but not cholinergic, deafferentation of prefrontal cortex impairs attentional set-shifting.

McGaughy J, Ross RS, Eichenbaum H (2008) Noradrenergic, but not cholinergic, deafferentation of prefrontal cortex impairs attentional set-shifting. Neuroscience 153:63-71. doi: 10.1016/j.neuroscience.2008.01.064

Summary: Norepinephrine and acetylcholine are involved in the mediation of attention, however, it is not yet clear whether the roles of these molecules are unique. This work utilizes a specific task shown to dissociate the roles played by the dorsolateral prefrontal cortex and the orbitofrontal cortex in primates. Rats received 5-ng infusions of anti-DBH-SAP (Cat. #IT-03) or 192-IgG-SAP (Cat. #IT-01) into each hemisphere. The type of lesion had an effect on attentional shifts and reaction to irrelevant stimuli.

Related Products: Anti-DBH-SAP (Cat. #IT-03), 192-IgG-SAP (Cat. #IT-01)

Effects of saporin-induced lesions of three arousal populations on daily levels of sleep and wake.

Blanco-Centurion C, Gerashchenko D, Shiromani PJ (2007) Effects of saporin-induced lesions of three arousal populations on daily levels of sleep and wake. J Neurosci 27:14041-14048. doi: 10.1523/JNEUROSCI.3217-07.2007

Summary: Orexin neurons in the basal forebrain, tuberomammillary nucleus (TMN), and locus ceruleus (LC) are thought to regulate arousal. Rats were injected with two or three of the following targeted conjugates: anti-DBH-SAP (Cat. #IT-03), 0.25 µl bilateral injections of 1 µg/µl into the LC; orexin-SAP (Cat. #IT-20), 0.25 µl injection of 0.25 µg/µl into the TMN; 192-IgG-SAP (Cat. #IT-01), 3 µl injection of 2 µg/µl into the lateral ventricle. Small differences were observed in sleep architecture, but the data do not support the traditional hypothesis that these three areas of the brain are essential links in the control of wake levels.

Related Products: Anti-DBH-SAP (Cat. #IT-03), Orexin-B-SAP (Cat. #IT-20), 192-IgG-SAP (Cat. #IT-01)

Prefrontal cortical norepinephrine depletion does not impair spatial working memory in rats

King M, Jentsch JD (2007) Prefrontal cortical norepinephrine depletion does not impair spatial working memory in rats. Neuroscience 2007 Abstracts 645.16/CCC18. Society for Neuroscience, San Diego, CA.

Summary: The midbrain dopamine neurons are thought to encode a reward prediction error signal (Schultz et al., 1997; Bayer & Glimcher, 2005). Parkinson's disease (PD) is characterized by a loss of nigral dopamine neurons. Dopaminergic drugs including the dopamine precursor L-Dopa and D2 receptor agonists are taken to relieve disease symptoms. We hypothesized that patients with moderate PD (1) show atypical reinforcement learning off dopaminergic medication due to dopamine neuron loss, and (2) show more normal reinforcement learning on dopaminergic drug therapy. We developed a method to rapidly assess reinforcement learning in human subjects (Rutledge et al., SfN 2005) adapted from matching law tasks used in monkeys (Sugrue et al., 2004; Lau & Glimcher, 2005). On each trial, subjects choose one of two animated crab traps. Rewards (crabs worth $0.10) were scheduled for the two targets with different independent rates. Scheduled rewards remained available until the associated target was chosen, as in the original matching law experiments (Herrnstein, 1961). After a 5-minute training period, subjects completed 800 trials as we varied reward probabilities across blocks. PD patients (n=19) completed one session on and one off dopaminergic medication. Age-matched controls (n=21) and healthy young subjects (n=20) completed one session. We found that young and elderly control subjects had similar reinforcement learning rates, but learning rates were reduced in PD patients (when tested off medication). Learning rates in the same PD patients were restored to control levels when dopaminergic drugs were administered. We also found that the reinforcement-independent strategies of our subjects were influenced by dopamine. Young subjects tended to alternate targets independent of reward history. In contrast, elderly subjects (who suffer some dopamine neuron loss) had a tendency to perseverate in their choices. This tendency was increased in PD patients (off medication), but restored to control levels when dopaminergic drugs were administered. This effect on choice is not explained by existing models of dopamine function. These data support a role for dopamine in human reinforcement learning. Future models of decision making in reinforcement learning tasks must also account for a reward-independent effect of dopamine on choice behavior.

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Locus coeruleus (LC) is involved in sustaining arousal

Gompf HS, Fuller PM, Saper CB, Lu J (2007) Locus coeruleus (LC) is involved in sustaining arousal. Neuroscience 2007 Abstracts 736.3/UU16. Society for Neuroscience, San Diego, CA.

Summary: The locus coeruleus (LC) has traditionally been thought to be involved in arousal; however, lesions of the LC have minimal effects on basal sleep-wake behavior. We propose that the LC instead may be required to sustain arousal under conditions of environmental challenge. To test this hypothesis, we intraventricularly injected saline, or 0.25, 0.5, or 1µg anti-DBH-saporin (DBH-SAP selectively lesions the LC), and implanted EEG/EMG electrodes. On recording days, each animal was paired with a normal rat (social interaction) and presented with novel objects every hour for 5 hours from ZT 6 to ZT 11. We then repeated the same experiment for 2.5 hrs and immunostained tissue for Fos and TH or Fos and DBH. We also repeated the same experiment in rats with unilateral LC lesion by 6-OHDA. During 5 hr of stimulation with novel objects and social interaction (distracting stimuli, DS), controls or partial LC lesioned animals (0.25 µg DBH-SAP) spent 83 ± 8% and 92 ± 4% awake respectively (n = 3 and 4, p = 0.4) whereas animals with complete LC lesions (0.5 and 1 µg) spent significantly less time in wakefulness (59 ± 4% and 66 ± 5% respectively, n = 3 and 4, p = 0.0005). The reduction of wakefulness occurred primarily during the second 30 mins of each hour. Following DS exposure, Fos was highly expressed in the cerebral cortex in both LC lesioned groups and controls. Furthermore, we found a correlation (R2 = 0.79) between the remaining LC neurons and wakefulness under DS. Rats with loss of one LC showed no changes in wakefulness, and Fos was highly and symmetrically induced in the cerebral cortex. Our results suggest that the LC is specifically involved in sustaining arousal.

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Noradrenergic denervation of dorsal medial prefrontal cortex (mPFC) modulates paraventricular hypothalamic responses to acute restraint stress

Radley JJ, Sawchenko PE (2007) Noradrenergic denervation of dorsal medial prefrontal cortex (mPFC) modulates paraventricular hypothalamic responses to acute restraint stress. Neuroscience 2007 Abstracts 198.4/ZZ13. Society for Neuroscience, San Diego, CA.

Summary: The dorsal mPFC is implicated in restricting the hypothalamo-pituitary-adrenal (HPA) axis response to acute emotional stress via its influence on neuroendocrine effector mechanisms represented in the paraventricular hypothalamic nucleus (PVH). The afferents that provide for mPFC engagement during stress may include ascending noradrenergic projections from the locus coeruleus (LC), which are known to be stress-responsive and capable of modulating attentional mechanisms and other aspects of mPFC function. Arguing against such a role for LC-mPFC projections is evidence that LC lesions attenuate PVH/HPA responses to acute emotional stress. Here we sought to clarify the role of the noradrenergic innervation of mPFC in acute stress-induced PVH activation. Rats received injections of the axonally transported catecholamine immunotoxin, anti-dopamine-β-hydroxylase (DBH)-saporin, centered in the prelimbic area, or sham injections of IgG-saporin or saline. 14 days later, rats were subjected to 30 min of restraint and perfused 2 h later. Immunohistochemical localization of the immediate-early gene product, Fos, was employed as an index of cellular activation in PVH. Cell counts revealed that acute stress reliably provoked marked increases in the number of Fos-labeled neurons in the PVH of all restrained groups relative to unstressed controls. Among stressed groups, anti-DBH-saporin lesions in the dorsal mPFC decreased activational responses in the PVH by 30%, relative to sham-lesioned animals, that were focused in the hypophysiotropic (dorsal medial parvocellular) subdivision. DBH immunostaining revealed a virtually complete noradrenergic denervation of the prelimbic area in immunotoxin-treated animals, while the ventral mPFC (infralimbic area) remained intact. Cortical fields dorsally and laterally adjoining the target area displayed a partial denervation, consistent with local collateralization of prelimbic-projecting LC neurons. While these data are consistent with a role for LC-mPFC projections in facilitating restraint-induced PVH engagement, it remains to be determined how this perspective may be reconciled with prior evidence indicating that mPFC serves normally to inhibit PVH/HPA responses to acute emotional stress.

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Experimental dissociation of neural circuits underlying conditioned avoidance and hypophagic responses to lithium chloride.

Rinaman L, Dzmura V (2007) Experimental dissociation of neural circuits underlying conditioned avoidance and hypophagic responses to lithium chloride. Am J Physiol Regul Integr Comp Physiol 293(4):R1495-1503. doi: 10.1152/ajpregu.00393.2007

Summary: Lithium chloride (LiCl) is frequently used to study neural attributes of “sickness behavior.” Previous work by these authors showed that noradrenergic neurons (NA) in the nucleus of the solitary tract (NST) are involved in the inhibition of food uptake by cholecystokinin. Here, 20 ng total of anti-DBH-SAP (Cat. #IT-03) was injected into the NST of rats. Lesioned animals demonstrated significantly reduced inhibition of food intake in response to LiCl, but conditioned flavor avoidance was left intact.

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Specificity and generality of the involvement of catecholaminergic afferents in hypothalamic responses to immune insults.

Schiltz JC, Sawchenko PE (2007) Specificity and generality of the involvement of catecholaminergic afferents in hypothalamic responses to immune insults. J Comp Neurol 502:455-467. doi: 10.1002/cne.21329

Summary: Interleukin-1 (IL-1) is one of the cytokines that mediates interactions between the immune system and the central nervous system. 380-ng injections of anti-DBH-SAP (Cat. #IT-03) were made into the paraventricular nucleus (PVH) of rats. Saporin (Cat. #PR-01) and mouse IgG-SAP (Cat. #IT-18) were used as controls. Lesioned animals demonstrated reduced responses to administration of IL-1, but restraint stress responses were left intact. The data suggest that ascending catecholaminergic projections mediate PVH response to IL-1.

Related Products: Anti-DBH-SAP (Cat. #IT-03), Saporin (Cat. #PR-01), Mouse IgG-SAP (Cat. #IT-18)

Hindbrain catecholamine neurons control multiple glucoregulatory responses.

Ritter S, Dinh TT, Li AJ (2006) Hindbrain catecholamine neurons control multiple glucoregulatory responses. Physiol Behav 89(4):490-500. doi: 10.1016/j.physbeh.2006.05.036

Summary: Glucose deficit evokes many responses in the brain. Recently these workers have been focusing on mechanisms eliciting glucoregulatory responses; the focus has settled on catecholaminergic neurons in the hindbrain. In a series of experiments rats received injections of anti-DBH-SAP (Cat. #IT-03) into epinephrine (E) and norepinephrine (NE) terminal areas of hypothalamus and spinal cord. The data suggest that E/NE neurons coordinate various components of the behavioral response to glucoprivation.

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Selective depletion of cortical noradrenalin by anti-dopamine beta-hydroxylase-saporin impairs attentional function and enhances the effects of guanfacine in the rat.

Milstein JA, Lehmann O, Theobald DE, Dalley JW, Robbins TW (2007) Selective depletion of cortical noradrenalin by anti-dopamine beta-hydroxylase-saporin impairs attentional function and enhances the effects of guanfacine in the rat. Psychopharmacology (Berl) 190(1):51-63. doi: 10.1007/s00213-006-0594-x

Summary: Building on previous work, the authors examined the effect of cortical noradrenalin depletion on a reaction time task. Rats received 0.2 µg-intracortical infusions of anti-DBH-SAP (Cat. #IT-03), then were trained in a reaction time task. The effect of guanfacine, a selective a-2 adrenergic agonist was also tested in these animals. Lesioned rats were not impaired on the baseline task, but were slower and less accurate during high rate conditions. Guanfacine only affected the lesioned animals.

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Role of catecholaminergic neurons of the caudal ventrolateral medulla in cardiovascular responses induced by acute changes in circulating volume in rats.

Pedrino GR, Maurino I, de Almeida Colombari DS, Cravo SL (2006) Role of catecholaminergic neurons of the caudal ventrolateral medulla in cardiovascular responses induced by acute changes in circulating volume in rats. Exp Physiol 91(6):995-1005. doi: 10.1113/expphysiol.2006.034611

Summary: Catecholaminergic neurons in the caudal ventrolateral medulla (CVLM) are thought to help regulate body fluid homeostasis and cardiovascular response due to changes in circulating volume. The authors injected 6.3 ng of anti-DBH-SAP (Cat. #IT-03) into the CVLM of rats, and measured several physiological parameters following an injection of hypertonic or isotonic saline. Data from the lesioned rats indicate that catecholaminergic neurons mediate the cardiovascular response to volume expansion or increases in sodium levels.

Related Products: Anti-DBH-SAP (Cat. #IT-03)

Noradrenergic inputs to the bed nucleus of the stria terminalis and paraventricular nucleus of the hypothalamus underlie hypothalamic-pituitary-adrenal axis but not hypophagic or conditioned avoidance responses to systemic yohimbine.

Banihashemi L, Rinaman L (2006) Noradrenergic inputs to the bed nucleus of the stria terminalis and paraventricular nucleus of the hypothalamus underlie hypothalamic-pituitary-adrenal axis but not hypophagic or conditioned avoidance responses to systemic yohimbine. J Neurosci 26(44):11442-11453. doi: 10.1523/JNEUROSCI.3561-06.2006

Summary: Yohimbine (YO) is an a2 adrenoceptor antagonist that increases transmitter release from adrenergic/noradrenergic (NA) neurons. The authors investigated whether NA inputs to the bed nucleus of the stria terminalis (BNST) were required for YO effects. After receiving 11 ng of anti-DBH-SAP (Cat. #IT-03) in the left and right BNST, rats displayed a marked decrease in the hypothalamic-pituitary-adrenal axis in response to YO administration.

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The effects of a norepinephrine reuptake blocker, atomoxotine, on an attentional set shifting impairment caused by prefrontal lesions

McGaughy JA (2006) The effects of a norepinephrine reuptake blocker, atomoxotine, on an attentional set shifting impairment caused by prefrontal lesions. Neuroscience 2006 Abstracts 749.17. Society for Neuroscience, Atlanta, GA.

Summary: There is substantial evidence to support the role of norepineprhine (NE) in selective attention. The NE system is hypothesized to maintain task-related attentional focus and allow shifts of attention (Aston-Jones and Cohen, 2005). These unique attentional functions correlate with changes in the firing patterns in locus coeruleus. Previous work in our lab has shown that NE lesions of the medial prefrontal cortex produces robust impairments in the ability of rats to perform an attentional set-shift, though acquisition of the attentional set and reinforcement reversal learning were spared. The current study assesses the effectiveness of atomoxotine, a NE reuptake blocker, in remediating these deficits. This drug is currently used in the treatment of attention deficit disorder and may restore balance to the noradrenergic system of the frontal cortex in these patients. Male, Long-Evans rats received lesions of the medial wall of the prefrontal cortex using dopamine beta-hydroxylase saporin (DBH-SAP) to produce selective noradrenergic deafferentation. The performance of DBH-SAP rats was compared to sham-lesioned (SHAM) rats in a test of attentional set-shifting after intraperitoneal injections of atomoxotine (0.0, 0.1,0.3, 0.9 mg/kg) 15 minutes prior to the test of attentional set-shifting. During the attentional set shifting task (Birrell and Brown 1999), rats were exposed to complex stimuli (texturized, scented pots filled with digging media). Initially rats were reinforced for focusing attention on one stimulus dimension, e.g. scent, during the tests of complex discriminations and reinforcement reversals. In tests of attentional set-shifting, subjects were required to inhibit attention to the previously reinforced dimension e.g. scent and learn that a new dimension e.g. texture predicted reinforcement.These results confirm that NE deafferentation of prefrontal cortex impairs the ability of rats to shift attention from the initially reinforced dimension to another dimension, e.g. when texture not odor now predicts reinforcement. Low doses of atomoxotine ameliorate the set-shifting impairments of DBH-SAP rats but hindered the performance of SHAM rats. These data suggest that shifts of attentional set require an optimal level of release of NE in the frontal cortex with both high and low levels of NE causing impairments in these abilities.

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Noradrenergic nuclei involved in sensory input during mating project to the ventromedial hypothalamus and are involved in mating-induced pseudopregnancy in female rats

Northrop LE, Erskine MS (2006) Noradrenergic nuclei involved in sensory input during mating project to the ventromedial hypothalamus and are involved in mating-induced pseudopregnancy in female rats. Neuroscience 2006 Abstracts 661.23. Society for Neuroscience, Atlanta, GA.

Summary: The ventrolateral region of the ventromedial hypothalamus (VMHvl) is known to control female sexual receptivity through the activity of ovarian steroids in the female rat. These receptors are thought to aide in the steroid-dependent facilitation of the lordosis posture. Besides harboring estrogen and progesterone receptors, dense numbers of noradrenergic receptors are also present in the VMHvl. Previous research has shown that norepinephrine is released in significant amounts within the VMHvl after a female receives vaginocervical stimulation (VCS). At the time of mating, the vaginocervical sensory input travels from the brainstem, through the ventral noradrenergic bundle (VNAB), and finally to the VMH. Sufficient amounts of VCS are necessary for inducing twice daily prolactin surges, which are required for the initiation of pseudopregnancy (PSP). To distinguish whether these cells play a role in mating-induced PSP, they were selectively lesioned using the immunotoxin anti-dopamine-β-hydroxylase-saporin (DBH-SAP) 10 days prior to mating. Females were given bilateral VMHvl infusions of either 60ng/0.6µl of DBH-SAP or 2ng/0.6µl of IGG-SAP (non-specific control). Ten days following infusion on proestrous, females received one of two treatments: no VCS (home cage), or a sufficient amount of VCS (15 intromissions from males) to induce PSP. PSP was measured using vaginal smears and serum PRL concentrations. The next witnessed proestrous day after mating, females were mated again with the same type of stimulus as previously administered and perfused 90 min later. The brainstems were cut in 30µm sections, and ICC was used to visualize DBH and FOS immunoreactivity (IR). FOS-IR and DBH-IR cells were counted in the A2 and A1 cell regions, components of the VNAB. DBH-SAP infused females that received 15I showed 50% induction of PSP whereas IGG-SAP (15I) females showed 100% induction of PSP. None of the home cage rats became PSP . VMHvl DBH-SAP infusions significantly decreased DBH/FOS-IR expression in A2 and A1 nuclei, as well as decreased expression in DBH-IR in A2 nuclei compared to IGG-SAP infused females. Our results show that A1 and A2 noradrenergic cells which innervate the VMHvl are required for initiation of P/PSP.

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Catecholaminergic afferents are required for hypothalamic parvicellular paraventricular neurons to transduce signals associated with hypoglycemia into p44/42 MAP kinase phosphorylation events

Rapp KL, Khan AM, Watts AG (2006) Catecholaminergic afferents are required for hypothalamic parvicellular paraventricular neurons to transduce signals associated with hypoglycemia into p44/42 MAP kinase phosphorylation events. Neuroscience 2006 Abstracts 355.9. Society for Neuroscience, Atlanta, GA.

Summary: Hypoglycemia activates CRH neuroendocrine neurons in the hypothalamic paraventricular nucleus (PVH), thereby rapidly elevating plasma ACTH and corticosterone concentrations. Hindbrain-originating catecholaminergic (CA) neurons projecting to the PVH facilitate ACTH release after insulin-induced hypoglycemia; however, the intracellular signaling mechanisms that CRH neurons use to transduce CA signals into secretogogue function are unknown. We have previously shown that p44 and/or p42 MAP kinases (ERK1/2) are phosphorylated in CRH neurons after 2-deoxy-D-glucose challenge (Endoc. v145:351, 2004). We now ask: Are hindbrain-originating CA projections to the PVH essential for ERK1/2 phosphorylation in response to insulin-induced hypoglycemia? Male Sprague-Dawley rats received acute bilateral PVH microinjections of either saporin toxin conjugated (DSAP) to an antiserum against dopamine beta hydroxylase (DBH) or conjugated to a non-targeted mouse IgG (control mIgG-SAP), were fitted with jugular catheters, and allowed to recover. On the day of testing, plasma glucose was measured just before the onset of hypoglycemia (induced via insulin bolus [2U/kg, i.v.]) and then 10 and 30 min thereafter. Rats were then anesthetized and transcardially perfused. Brain tissue processed for dual immunofluorescence using antibodies raised against DBH and phospho-ERK1/2 was visualized by confocal microscopy. Baseline plasma glucose levels did not differ significantly between groups (5.66 ± 0.26 mM), but were significantly reduced in each group when compared to baseline after 10 (1.48 ± 0.12 mM) and 30 (1.92 ± 0.12 mM) minutes. DSAP rats displayed marked loss of DBH immunostaining in the PVH relative to controls, with concomitant loss of phospho-ERK1/2 immunostaining within the parvicellular PVH. Further analysis was performed to address the effect of DSAP on DBH staining and ERK1/2 recruitment in the hindbrain and arcuate nucleus. Our results confirm that phosphorylation of ERK1/2 in parvicellular PVH after insulin-induced hypoglycemia requires intact CA afferent innervation. These data contribute to our understanding of how intracellular signaling is regulated in parvicellular PVH neurons. They also underscore an emerging importance of CA afferents for mediating neuroendocrine responses to systemic alterations in glucose.

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Glucoprivation enhances dopamine-beta-hydroxylase gene expression in hindbrain catecholamine cells

Li A, Ritter S (2006) Glucoprivation enhances dopamine-beta-hydroxylase gene expression in hindbrain catecholamine cells. Neuroscience 2006 Abstracts 359.12. Society for Neuroscience, Atlanta, GA.

Summary: Hindbrain catecholaminergic neurons are key participants in systemic glucoregulation. Using in situ hybridization, we investigated the effects of glucoprivation on gene expression of dopamine-beta-hydroxylase (DBH), a key enzyme for catecholamines synthesis, to further define the catecholamine subpopulation activated by glucoprivation. Glucoprivation induced by systemic injection of the glycolytic inhibitor, 2-deoxy-D-glucose (2DG, 250 mg/kg body weight) increased total DBH mRNA expression in caudal ventrolateral medullary cell groups (namely, A1, the A1/C1 overlap, and middle C1) from 6 - 49 times control levels. In retrofacial C1, A5 and A7 no enhancement was observed. In the dorsomedial medulla, DBH mRNA hybridization signal was modestly increased (tripled) in cell group A2, but not in the area postrema. Furthermore, a previous hypothalamic microinjection of the retrogradely transported immunotoxin, anti-DBH-saporin, profoundly reduced DBH-positive cells in hindbrain, and abolished the 2DG-stimulated increases of DBH mRNA expression in the caudal ventrolateral medulla and A2 regions. The strong glucoprivation-induced enhancement of DBH gene expression in particular cell populations is consistent with the demonstrated importance of catecholaminergic neurons for glucoregulation and provides further evidence for functional specialization within the catecholamine cell population.

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Lesions of the dorsal noradrenergic bundle impair attentional set-shifting in the rat

Tait DS, Brown VJ, Farovik A, Theobald DE, Dalley JW, Robbins TW (2006) Lesions of the dorsal noradrenergic bundle impair attentional set-shifting in the rat. Neuroscience 2006 Abstracts 264.4. Society for Neuroscience, Atlanta, GA.

Summary: Rats with medial prefrontal cortex (mPFC) lesions are impaired in attentional set shifting (Birrell and Brown, 2000, J Nsci, 20:4320-4324). The mPFC receives multiple projections, but norepinephrine (NE) has previously been reported to modulate attention by its action in the mPFC (for review see Dalley et al., 2004, Nsci Biobeh Rev, 28:771-784), including shifting attentional set. Indeed, there is recent evidence that increasing NE in the mPFC by autoreceptor antagonism improves set-shifting performance in rats (Lapiz and Morilak, 2006, Nsci, 137:1039-1049). Furthermore, reduction of prefrontal NE by infusion of anti-DBH-saporin into PFC has been shown to impair attentional set-shifting in rats (Eichenbaum et al., 2003, SfN Abstract 940.7). The main source of noradrenergic input to the mPFC is from locus coerulus via the dorsal noradrenergic bundle (DNAB). This study examined the effect of lesions of the DNAB on the acquisition, maintenance and shifting of attentional set. Eleven male Lister-hooded rats received bilateral DNAB lesions by infusion of 6-hydroxydopamine (4μg in 2μl each side) at (nosebar -2.4mm) AP -6.0mm, ML ±1.0mm, DV -5.0mm (from dura). Twelve control rats received injections of vehicle. Rats learned to dig for bait in bowls then learned two simple discriminations - based on the bowls odor or the digging substrate - to a criterion of six consecutive correct trials. The next day, a series of discriminations tested acquisition of novel discriminations (both intra (ID) and extradimensional (ED)) and reversal learning. Trials to criterion, incorrect trials and dig-latencies were recorded and analysed. At conclusion of testing, brain tissue samples were analysed for NE content by HPLC-ECD. All rats required more trials to reverse previously learned associations, and to learn new discriminations when attentional refocusing was required (ED shift). Rats with DNAB lesions were unimpaired at reversal stages, but were impaired at the ED acquisition stage. Lesioned rats showed reductions of NE levels in mPFC (up to 95% in the infralimbic region, 89% in the prelimbic region and 93% in cingulate area Cg1). These data provide further evidence for the role of NE in attentional set-shifting, and combine with previous data to elucidate the mechanisms by which mPFC mediates attentional set-shifting in the rat.

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Immunolesions of glucoresponsive projections to the arcuate nucleus alter glucoprivic-induced alterations in food intake, luteinizing hormone secretion, and GALP mRNA, but not sex behavior in adult male rats.

Fraley GS (2006) Immunolesions of glucoresponsive projections to the arcuate nucleus alter glucoprivic-induced alterations in food intake, luteinizing hormone secretion, and GALP mRNA, but not sex behavior in adult male rats. Neuroendocrinology 83(2):97-105. doi: 10.1159/000094375

Summary: In this work the author looked at the role hypothalamic glucose may play in reproductive function. 42 ng of anti-DBH-SAP (Cat. #IT-03) was injected dorsal of the arcuate nucleus of rats, which were then given glucoprivic challenges. Feeding and sex behavior were decreased during glucoprivation; sex behavior was also decreased in control animals. The data demonstrate the involvement of A1/C1 efferents to the ventromedial hypothalamus in glucostatic regulation of various processes.

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Hypotensive hypovolemia and hypoglycemia activate different hindbrain catecholamine neurons with projections to the hypothalamus.

Dinh TT, Flynn FW, Ritter S (2006) Hypotensive hypovolemia and hypoglycemia activate different hindbrain catecholamine neurons with projections to the hypothalamus. Am J Physiol Regul Integr Comp Physiol 291(4):R870-R879. doi: 10.1152/ajpregu.00094.2006

Summary: Hypovolemia, a decrease in blood plasma volume, results in secretion of arginine vasopressin (AVP). This work investigates the role of hindbrain catecholamine neurons in hypovolemia-induced AVP secretion. Rats were treated with bilateral 42 ng injections of anti-DBH-SAP (Cat. #IT-03) into the paraventricular nucleus of the hypothalamus, and hypovolemia was induced by blood withdrawal. Treated animals displayed severely impaired AVP response, as well as lower food intake and corticosterone secretion in response to insulin.

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Attenuation of homeostatic responses to hypotension and glucoprivation after destruction of catecholaminergic rostral ventrolateral medulla (RVLM) neurons.

Madden CJ, Stocker SD, Sved AF (2006) Attenuation of homeostatic responses to hypotension and glucoprivation after destruction of catecholaminergic rostral ventrolateral medulla (RVLM) neurons. Am J Physiol Regul Integr Comp Physiol 291(3):R751-R759. doi: 10.1152/ajpregu.00800.2005

Summary: C1 neurons in the RVLM express dopamine-beta-hydroxylase (DBH). Anti-DBH-SAP (Cat. #IT-03) was used to eliminate these neurons and examine cardiovascular homeostasis in response to a physiological challenge such as hypotension. 21 ng of anti-DBH-SAP was injected into the RVLM of rats. After food and water had been removed from the cage, the lesioned animals were treated with hydralazine to reduce blood pressure. The results demonstrate that RVLM-C1 cells are involved in responses to homeostatic challenges.

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Differential responsiveness of dopamine-beta-hydroxylase gene expression to glucoprivation in different catecholamine cell groups.

Li AJ, Wang Q, Ritter S (2006) Differential responsiveness of dopamine-beta-hydroxylase gene expression to glucoprivation in different catecholamine cell groups. Endocrinology 147(7):3428-3434. doi: 10.1210/en.2006-0235

Summary: This work examines how subpopulations of hindbrain catecholaminergic neurons participate in systemic glucoregulation. Rats were treated with bilateral 42 ng infusions of anti-DBH-SAP (Cat. #IT-03) into the paraventricular nucleus of the hypothalamus. Dopamine-beta-hydroxylase (DBH) expression in glucoprivic animals was then analyzed by in situ hybridization and immunohistochemistry. The data demonstrate that the ventrolateral medulla contains most of the catecholamine neurons responsive to glucoprivation.

Related Products: Anti-DBH-SAP (Cat. #IT-03), Saporin (Cat. #PR-01)

Catecholamine neurones in rats modulate sleep, breathing, central chemoreception and breathing variability.

Li A, Nattie E (2006) Catecholamine neurones in rats modulate sleep, breathing, central chemoreception and breathing variability. J Physiol 570(Pt 2):385-396. doi: 10.1113/jphysiol.2005.099325

Summary: Brainstem catecholamine (CA) neurons are thought to modulate the processing of sensory information and participate in the control of breathing. Using a 5 µg injection of anti-DBH-SAP (Cat. #IT-03), or a control injection of mouse-IgG-SAP (Cat. #IT-18) into the fourth ventricle, the authors investigated breathing frequency and wakefulness. The results suggest that CA neurons promote wakefulness, participate in central respiratory chemoreception, stimulate breathing frequency, and minimize breathing variability during REM sleep.

Related Products: Anti-DBH-SAP (Cat. #IT-03), Mouse IgG-SAP (Cat. #IT-18)

Immunolesions of glucoresponsive projections to the arcuate nucleus alter glucoprivic feeding and luteinizing hormone secretion but not sex behavior in adult male rats

Fraley GS (2005) Immunolesions of glucoresponsive projections to the arcuate nucleus alter glucoprivic feeding and luteinizing hormone secretion but not sex behavior in adult male rats. Neuroscience 2005 Abstracts 758.7. Society for Neuroscience, Washington, DC.

Summary: Metabolic signals such as insulin, leptin and glucose are known to alter hypothalamic function. Although insulin and leptin are known to directly alter hypothalamic areas that regulate reproduction, the mechanisms by which glucose alters reproductive function are not as clear. Catecholaminergic neurons in the A1/C1 region of the hindbrain are glucose-responsive and project to the arcuate nucleus. To determine if this pathway is involved in the regulation of sex behavior and luteinizing hormone (LH) secretion, this catecholamingergic pathway was lesioned by injecting saporin conjugated to anti-dopamine-β-hydroxalase (DSAP) or unconjugated saporin (SAP) into the arcuate nucleus of adult male rats. Rats were given glucoprivic challenges then feeding and sex behaviors were observed. As was expected, the DSAP treated rats showed a significant decreased in feeding during glucoprivation (250 mg/kg 2-deoxy-D-glucose, 2DG) compared to SAP controls (p < 0.05). Glucoprivation caused a significant reduction in sex behavior (p < 0.05) in both SAP and DSAP animals equally, compared to saline treatments in either treatment group. At the end of the experiment, animals were given a final challenge with 2DG or saline, killed by decapitation and trunk blood was assayed for plasma LH levels. In SAP animals, 2DG elicited a significant decrease in plasma LH levels (p < 0.05). However, in DSAP animals there was a significant increase (p < 0.05) in plasma LH levels compared to saline-treated rats. These data indicate that the A1/C1 efferents to the ventromedial hypothalamus are involved in the glucostatic regulation of feeding behavior and LH secretion, but not sex behavior in the adult male rat.

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Immunotoxic destruction of catecholaminergic pathways disrupts the onset of puberty in the female rat

Vander Schaaf EB, Lusk JD, Jarrard LE, I’Anson H (2005) Immunotoxic destruction of catecholaminergic pathways disrupts the onset of puberty in the female rat. Neuroscience 2005 Abstracts 406.10. Society for Neuroscience, Washington, DC.

Summary: Ascending catecholaminergic (NE/E) pathways from the brainstem terminate near gonadotropin releasing hormone cell bodies and terminals in the hypothalamus. To determine the significance of NE/E pathways in regulating puberty onset, a neurotoxin (dopamine-ß-hydroxylase conjugated to saporin, DSAP) was administered intracerebrally to developing female rats to destroy this pathway and the timing of puberty onset was monitored. DSAP or vehicle (unconjugated saporin, SAP) was injected into the hypothalamic paraventricular nucleus on Days 23-25 of age (n=10 per group). An additional 8 rats served as untreated controls. Growth rate was monitored daily and on surgery days SAP & DSAP rats grew at a slower rate than controls. Thus, food intake of control rats was temporarily adjusted to ensure that growth rate was similar between groups. Onset of puberty and cycle length were monitored via vaginal cytology. 2-Deoxy-D-glucose-induced glucoprivation determined which rats received complete DSAP lesions, since lesioned rats do not acutely increase food intake when glucose-deprived. Results showed that NE/E neurons were adequately lesioned in seven of ten DSAP rats. Puberty onset (time of first estrus) was delayed in DSAP-lesioned rats (40.86 ± 1.79 days of age, n=7) compared to vehicle or control rats (36.25 ± 0.31 days of age, n=10; 37.50 ± 0.31 days of age, n=8). Estrous cycle length of DSAP rats (5.38 ± 0.46 days, n=7) was not significantly longer than in vehicle or control rats (4.91 ± 0.18 days, n=10; 4.40 ± 0.12 days, n=8). Thus, lesioning the NE/E pathway caused delay in onset of puberty in female rats, but no significant change in estrous cycle length. Therefore, ascending catecholaminergic pathways from the brainstem are important in determining puberty onset timing. First estrus did eventually occur in DSAP rats, suggesting that other neural pathways may be activated to regulate puberty onset and estrous cyclicity in its absence.

Related Products: Anti-DBH-SAP (Cat. #IT-03)

Experimental dissociation of neural circuits underlying anorexic and conditioned avoidance responses to LiCl in rats

Rinaman L, Maldovan V (2005) Experimental dissociation of neural circuits underlying anorexic and conditioned avoidance responses to LiCl in rats. Neuroscience 2005 Abstracts 529.7. Society for Neuroscience, Washington, DC.

Summary: The central nucleus of the amygdala (CeA) receives viscerosensory input from noradrenergic (NA) neurons in the nucleus of the solitary tract (NST) and from peptidergic non-NA neurons in the lateral parabrachial nucleus (laPBN). A previous study (J. Neurosci. 23:10084-92) demonstrated that NA neurons in the caudal NST are necessary for cholecystokinin (CCK) to inhibit food intake in rats, but are unnecessary for CCK to activate Fos expression in the laPBN and CeA. The laPBN and CeA are integral components of central neural circuits that underlie the formation and expression of conditioned flavor avoidance (CFA). Thus, the neural substrates for treatment-induced anorexia may be separable from those for CFA. To test this idea, saporin toxin conjugated to an antibody against dopamine β hydroxylase was microinjected bilaterally into the caudal NST in adult male rats in order to selectively lesion NA neurons. Three weeks later, lesioned and sham control rats were tested for the ability of 0.15M LiCl (2% BW, i.p.) to inhibit food intake and to support conditioned flavor avoidance (CFA). Anorexia after LiCl was significantly blunted in lesioned rats compared to sham controls, similar to our previous findings in lesioned rats after CCK treatment. However, LiCl still supported robust CFA in lesioned rats, and its magnitude was similar to that seen in sham controls. A terminal Fos study revealed intact LiCl-induced activation of neural Fos expression in the laPBN and CeA in lesioned rats, despite significant loss of NA neurons in the caudal NST. These new findings support the view that NA neurons in the caudal NST are unnecessary for laPBN and CeA neural responses to viscerosensory stimulation, and also are unnecessary for the learning and expression of conditioned flavor avoidance.

Related Products: Anti-DBH-SAP (Cat. #IT-03)

Autonomic brainstem nuclei are linked to the hippocampus.

Castle M, Comoli E, Loewy AD (2005) Autonomic brainstem nuclei are linked to the hippocampus. Neuroscience 134(2):657-669. doi: 10.1016/j.neuroscience.2005.04.031

Summary: Stimulation of the vagal nerve has been reported to enhance memory, as well as be an effective treatment for epilepsy. The authors examined the underlying synaptic pathway. The right ventral CA1 hippocampal field of rats was lesioned with 42 ng of either anti-DBH-SAP (Cat. #IT-03), or 192-Saporin (Cat. #IT-01). The results indicate that both noradrenergic and cholinergic neurons are relay sites for this pathway.

Related Products: 192-IgG-SAP (Cat. #IT-01), Anti-DBH-SAP (Cat. #IT-03)

Molecular neurosurgery with targeted toxins

Wiley RG, Lappi DA (2005) Molecular neurosurgery with targeted toxins. Humana Press, Totowa, New Jersey.

Summary: The idea behind the book was to provide a road map for the users of Molecular Neurosurgery to see how experienced scientists used these exceptional reagents in their work. Experiments with several targeted toxins are described, and readers can get an idea either specifically about a targeted toxin that they’re using, or about how a type of molecule is used and at what dosage, in a paradigm similar to theirs.

Related Products: 192-IgG-SAP (Cat. #IT-01), ME20.4-SAP (Cat. #IT-15), Anti-DBH-SAP (Cat. #IT-03), SSP-SAP (Cat. #IT-11), Dermorphin-SAP / MOR-SAP (Cat. #IT-12), IB4-SAP (Cat. #IT-10), CTB-SAP (Cat. #IT-14)

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Featured Article: Noradrenergic inputs to the medial amygdala originate in the A1 and A2 cells groups and release norepinephrine after mating stimulation sufficient to induce pseudopregnancy

Northrop LE, Cameron N, Erskine M (2005) Featured Article: Noradrenergic inputs to the medial amygdala originate in the A1 and A2 cells groups and release norepinephrine after mating stimulation sufficient to induce pseudopregnancy. Targeting Trends 6(2)

Related Products: Anti-DBH-SAP (Cat. #IT-03)

Read the featured article in Targeting Trends.

Impairments in working memory and decision-taking processes in monkeys in a model of Alzheimer’s disease.

Dudkin KN, Chueva V, Makarov FN, Bich TG, Roer AE (2005) Impairments in working memory and decision-taking processes in monkeys in a model of Alzheimer's disease. Neurosci Behav Physiol 35(3):281-289.

Related Products: ME20.4-SAP (Cat. #IT-15), Anti-DBH-SAP (Cat. #IT-03)

An opposing time-dependent immune-modulating effect of the sympathetic nervous system conferred by altering the cytokine profile in the local lymph nodes and spleen of mice with type II collagen-induced arthritis.

Harle P, Mobius D, Carr DJ, Scholmerich J, Straub RH (2005) An opposing time-dependent immune-modulating effect of the sympathetic nervous system conferred by altering the cytokine profile in the local lymph nodes and spleen of mice with type II collagen-induced arthritis. Arthritis Rheum 52:1305-1313. doi: 10.1002/art.20987

Summary: In this work the authors examined the role of the sympathetic nervous system (SNS) in late stages of chronic arthritis. 5 µg intraperitoneal injections of anti-DBH-SAP (Cat. #IT-03) in mice were used to confirm that previous 6OHDA injections caused a sympathectomy. The results demonstrate that the SNS supports inflammation during the asymptomatic phase of arthritis, but inhibits inflammation during the chronic symptomatic phase.

Related Products: Anti-DBH-SAP (Cat. #IT-03)

Involvement of brainstem catecholaminergic inputs to the hypothalamic paraventricular nucleus in estrogen receptor alpha expression in this nucleus during different stress conditions in female rats.

Estacio MA, Tsukamura H, Reyes BA, Uenoyama Y, I'anson H, Maeda K (2004) Involvement of brainstem catecholaminergic inputs to the hypothalamic paraventricular nucleus in estrogen receptor alpha expression in this nucleus during different stress conditions in female rats. Endocrinology 145(11):4917-4926. doi: 10.1210/en.2004-0469

Summary: Norepinephrine release in the paraventricular nucleus (PVN) is increased during periods of metabolic stress. The authors hypothesized that noradrenergic inputs to the PVN may also mediate estrogen receptor a (ERa) expression in the PVN during metabolic stress. 20 ng of Anti-DBH-SAP (Cat. #IT-03) was injected bilaterally into the PVN of rats, and ERa expression was examined in several stress models. Results indicate that during metabolic stress catecholaminergic inputs to the PVN play a major role in mediating the induction of ERa expression.

Related Products: Anti-DBH-SAP (Cat. #IT-03)

Immunotoxic destruction of hindbrain catecholamine neurons impairs the vasopressin response to hypovolemia

Ritter S, Flynn FW, Dinh TT (2004) Immunotoxic destruction of hindbrain catecholamine neurons impairs the vasopressin response to hypovolemia. Neuroscience 2004 Abstracts 660.4. Society for Neuroscience, San Diego, CA.

Summary: In order to better understand the involvement of hindbrain catecholamine neurons in hypovolemia-induced vasopressin secretion, we lesioned these neurons selectively using anti-dopamine beta-hydroxylase (dbh) conjugated to the ribosomal toxin, saporin (DSAP). When injected into catecholamine terminal sites, this neurotoxin is selectively internalized by and retrogradely transported in dbh-containing neurons, destroying cell bodies that innervate the injection site. We microinjected DSAP or unconjugated saporin (SAP) control bilaterally into the medial hypothalamus of female rats to destroy catecholamine neurons innervating the magnocellular areas of the paraventricular nucleus (PVH). The lesion was verified at the conclusion of the experiment by analysis of dbh-immunoreactive terminals in the PVH and cell bodies in hindbrain catecholamine cell groups. Two weeks after DSAP injection, hypovolemia was induced by remote withdrawal of blood (1 ml/min for 4.5 min) using a chronically implanted intra-atrial catheter. Blood was sampled between 0-2 and 2-4.5 min and at 20 and 50 min after the start of blood withdrawal. Plasma vasopressin was extracted and analyzed using ELISA. The DSAP lesion severely impaired the vasopressin response. Responses at 20 min were 35 pg/ml in the SAP control and 21 pg/ml in the DSAP rats. Responses at 50 min were 45 pg/ml in the SAP and 23 pg/ml in the DSAP lesioned rats. Results indicate that hindbrain catecholamine neurons play a crucial role in full expression of the vasopressin response to hypovolemia.

Related Products: Anti-DBH-SAP (Cat. #IT-03)

Noradrenergic inputs to the bed nucleus of the stria terminalis (BNST) contribute to yohimbine-induced activation of BNST neurons and hypothalamic CRH neurons in rats

Banihashemi L, Rinaman L (2004) Noradrenergic inputs to the bed nucleus of the stria terminalis (BNST) contribute to yohimbine-induced activation of BNST neurons and hypothalamic CRH neurons in rats. Neuroscience 2004 Abstracts 426.10. Society for Neuroscience, San Diego, CA.

Summary: Noradrenergic (NA) inputs to the BNST and hypothalamus are implicated in behavioral and endocrine responses to stress and anxiety. Yohimbine (YO) increases transmitter release from NA terminals, which promotes anxiety and activates CRH neurons at the central apex of the HPA axis. We hypothesized that these effects require NA signaling within the BNST. To test this, saporin toxin conjugated to an antibody against dopamine beta hydroxylase (DSAP; 50-100 nl) was microinjected bilaterally into the BNST to eliminate its NA inputs in adult male Sprague-Dawley rats. After 2 weeks, DSAP-treated rats and intact control rats were injected with YO (0 or 5 mg/kg, i.p) and perfused with fixative 90 min later. Brain sections were processed to reveal DSAP lesion extent and YO-induced cFos activation. DSAP rats displayed nearly complete loss of NA terminals in the BNST, accompanied by moderate loss of hypothalamic NA terminals. Significantly fewer BNST neurons and hypothalamic CRH neurons were activated in DSAP rats after YO compared to activation in intact control rats, whereas parabrachial and central amygdala activation in DSAP rats was not diminished. We conclude that medullary NA neurons projecting to the lateral BNST collateralize to innervate the paraventricular hypothalamus, and that these NA projection neurons are necessary for YO to activate BNST and hypothalamic CRH neurons. Studies are ongoing to determine whether BNST-projecting NA neurons are necessary for YO to inhibit food intake or support conditioned flavor avoidance.

Related Products: Anti-DBH-SAP (Cat. #IT-03)

Brainstem catecholaminergic neurons participate in central chemoreception in NREM sleep and wakefulness

Nattie EE, Li A (2004) Brainstem catecholaminergic neurons participate in central chemoreception in NREM sleep and wakefulness. Neuroscience 2004 Abstracts 145.9. Society for Neuroscience, San Diego, CA.

Summary: In the locus ceruleus (LC), noradrenergic neurons are CO2 sensitive in vitro and focal acidification stimulates breathing in vivo. Do catecholaminergic (CA) neurons in general have a like role? To kill brainstem CA neurons we administered a conjugate of the cell toxin saporin with an antibody to dopamine-β-hydroxylase via the fourth ventricle in rats (N=7) using IgG-saporin conjugate injections as a control (N=6). We studied breathing in air, 3 and 7% CO2 during NREM sleep and wakefulness before and 7, 14, and 21 days after the injections. TH-ir noradrenergic neurons were significantly reduced in LC (-84%) and the A5 region (-78%) but not the A9 region. PNMT-ir adrenergic neurons were significantly reduced in C3 (-56%) and C1 (-60%) regions. Neither treatment affected room air breathing. In 3 and 7% CO2, IgG-SAP injections had no effect. In the lesion group, during 3% CO2 frequency (f) was significantly decreased (two-way ANOVA) and Δ ventilation (VE) (VE in 5% CO2 – VE in air) was significantly decreased in sleep. During 7% CO2, both absolute and Δ VE and f were significantly decreased in sleep and wakefulness, Δ VE by 25% in wakefulness and 28% in sleep at 21 days. Brainstem CA neurons participate in central chemoreception in vivo during both NREM sleep and wakefulness.

Related Products: Anti-DBH-SAP (Cat. #IT-03)

Role of noradrenergic mechanisms in sustained attention, impulse control, and effects of methylphenidate in rats: Possible relevance to ADHD

Milstein JA, Lehmann O, Theobald DEH, Dalley JW, Robbins TW (2004) Role of noradrenergic mechanisms in sustained attention, impulse control, and effects of methylphenidate in rats: Possible relevance to ADHD. Neuroscience 2004 Abstracts 123.6. Society for Neuroscience, San Diego, CA.

Summary: There has been renewed interest in noradrenergic (NA) modulation of sustained attention and impulse control both clinically, with the approval of the SNRI atomoxetine for the treatment of attention deficit hyperactivity disorder, as well as preclinically, in the mediation of the psychomotor effects of stimulants, where blockade of α1 adrenoreceptors counteracts the locomotor stimulant effects of d-amphetamine. The current study examines the role of NA in the modulation of sustained attention and impulse control using the 5-choice serial reaction time task (5CSRT) in rats. Experiment 1 examined the systemic antagonism of methylphenidate (MP)-induced impulsivity with either prazosin, an α1 adrenoreceptor antagonist, which antagonises the locomotor activating effects of amphetamine, or propranolol, a general β-adrenoreceptor blocker. Prazosin partially attenuated the MP-mediated increase in premature responding, but also caused generalised motor slowing, increasing both correct latency as well as latency to collect food reward. Propranolol completely abolished MP-induced impulsivity. This effect was centrally rather than peripherally mediated, as nadolol, a peripheral β-blocker failed to affect MP-induced premature responding. Other experiments examined the comparative effects of selective dopaminergic or serotonergic receptor blockade. A second experiment investigated the effects of selective anti-DBH saporin-induced prefrontal NA depletion. Animals with prefrontal depletions were unimpaired on the baseline version of the 5CSRT. However, they appeared to be slightly impaired under high event rate conditions. Effects of selective prefrontal NA depletion on MP-induced behavioural changes will also be examined. Taken together, these studies provide evidence for a role of noradrenaline in impulse control and the effects of MP.

Related Products: Anti-DBH-SAP (Cat. #IT-03)

Medullary noradrenergic neurons release norepinephrine in the medial amygdala in females in response to mating stimulation sufficient for pseudopregnancy.

Cameron NM, Carey P, Erskine MS (2004) Medullary noradrenergic neurons release norepinephrine in the medial amygdala in females in response to mating stimulation sufficient for pseudopregnancy. Brain Res 1022(1-2):137-147. doi: 10.1016/j.brainres.2004.07.022

Summary: Norepinephrine (NE) plays an important role in female reproductive function. While the ventral noradrenergic bundle is known to be necessary for transmitting the pseudopregnancy (PSP) response, the mechanism by which this occurs is not understood. The authors administered 20 ng of Anti-DBH-SAP (Cat. #IT-03) to the left posterodorsal medial amygdala of ovariectomized rats. The results indicate that NE may play an important role in the establishment of PSP.

Related Products: Anti-DBH-SAP (Cat. #IT-03)

Hindbrain catecholamine neurons mediate consummatory responses to glucoprivation.

Hudson B, Ritter S (2004) Hindbrain catecholamine neurons mediate consummatory responses to glucoprivation. Physiol Behav 82(2-3):241-250. doi: 10.1016/j.physbeh.2004.03.032

Summary: Norepinephrine (NE) and epinephrine (E) neurons appear to potently stimulate feeding behavior when administered to the hypothalamus. Previous work has indicated that these neurons play important roles in feeding responses due to glucoprivation. Bilateral 42 ng-injections of anti-DBH-SAP (Cat. #IT-03) were administered to rats to investigate the roles of NE and E neurons in the consummatory phase of the glucoprivic response. The results indicate that catecholaminergic neurons are involved in both appetitive and consummatory responses to glucoprivation.

Related Products: Anti-DBH-SAP (Cat. #IT-03)

Effects of hypocretin2-saporin and antidopamine-beta-hydroxylase-saporin neurotoxic lesions of the dorsolateral pons on sleep and muscle tone.

Blanco-Centurion C, Gerashchenko D, Salin-Pascual RJ, Shiromani PJ (2004) Effects of hypocretin2-saporin and antidopamine-beta-hydroxylase-saporin neurotoxic lesions of the dorsolateral pons on sleep and muscle tone. Eur J Neurosci 19(10):2741-2752. doi: 10.1111/j.0953-816X.2004.03366.x

Summary: Narcolepsy is linked to the loss of orexin (or hypocretin)-containing neurons in the brain. These neurons are located in the perifornical region of the posterior hypothalamus and innervate the locus coeruleus (LC). To investigate the role of the LC in sleep the authors injected 0.3 µl of 192-Saporin (Cat. IT-01) or anti-DBH-SAP (Cat. #IT-03) at 1 µg/µl. They also used 0.3 µl of orexin-SAP (Cat. #IT-20) at either 90 ng/µl or 60 ng/µl in a separate group of animals. The results indicate that orexin innervation to the pons plays a role in arousal from sleep.

Related Products: 192-IgG-SAP (Cat. #IT-01), Anti-DBH-SAP (Cat. #IT-03), Orexin-B-SAP (Cat. #IT-20)

Glucoprivation increases expression of neuropeptide Y mRNA in hindbrain neurons that innervate the hypothalamus.

Li AJ, Ritter S (2004) Glucoprivation increases expression of neuropeptide Y mRNA in hindbrain neurons that innervate the hypothalamus. Eur J Neurosci 19(8):2147-2154. doi: 10.1111/j.1460-9568.2004.03287.x

Summary: It is suspected that hypothalamic neuropeptide Y (NPY) innvervation of the hypothalamus contributes to glucoregulatory feeding. Along with mRNA studies, the authors injected 42 ng of anti-DBH-SAP (Cat. #IT-03) into the paraventricular nucleus. Elimination of the hindbrain catecholamine/NPY neurons abolished increases in NPY expression due to glucoprivic conditions. This response suggests that NPY hindbrain neurons play a role in glucoprivic feeding and other glucoregulatory responses.

Related Products: Anti-DBH-SAP (Cat. #IT-03)

Poster: Immunotoxic destruction of distinct catecholaminergic neuron populations disrupts the reproductive response to glucoprivation in female rats

Dinh TT, I’Anson H, Ritter S (2003) Poster: Immunotoxic destruction of distinct catecholaminergic neuron populations disrupts the reproductive response to glucoprivation in female rats. Neuroscience 2003 Abstracts 827.13. Society for Neuroscience, New Orleans, LA.

Summary: Chronic glucoprivation suppresses estrous cyclicity in hamsters (Schneider et al. 1997) and rats (I'Anson et al. 2003). This suppression can be viewed as an adaptive glucoregulatory response since by delaying pregnancy, it conserves metabolic fuels for maternal survival. Our previous work shows that corticosterone, feeding and adrenal medullary responses to glucoprivation are controlled by hindbrain glucose sensing cells and require activation of ascending or descending catecholamine neurons. The glucoreceptors responsible for the delay of estrous also appear to be located in hindbrain, since fourth ventricular infusion of low 2-deoxy-D-glucose (2DG) doses suppresses pulsatile LH secretion in rats (Nagatani et al. 1996). Here we tested the involvement of catecholamine neurons in suppressing estrous cycles during chronic glucoprivation. We microinjected the retrogradely transported immunotoxin, anti-dopamine beta hydroxylase (dbh)-conjugated to saporin (DSAP), bilaterally into the paraventricular nucleus of the hypothalamus (PVH) of female rats to selectively destroy dbh-containing catecholamine neurons projecting to this area. Neither DSAP nor unconjugated saporin (SAP) control injections altered basal estrous cycle length. To assess effects of chronic 2DG, rats were injected with 2DG (200 mg/kg every 6 hr for 72 hr) beginning 24 hr after detection of estrous following two normal 4-5 day cycles. Chronic glucoprivation increased cycle length significantly in 7/8 SAP controls but in only 1/8 DSAP rats. Lesion effectiveness and selectivity were confirmed by immunohistochemistry. Thus, hindbrain catecholamine neurons with projections to the PVH are not required for estrous cyclicity when metabolic fuels are abundant, but are required for inhibition of reproductive function during chronic glucose deficit.

Related Products: Anti-DBH-SAP (Cat. #IT-03)

Destruction of brainstem catecholamine neurons attenuates somatosympathetic reflex and responses to cholecystokinin

Neale JJ, Goodchild AK, Dampney RAL, Pilowsky PM (2003) Destruction of brainstem catecholamine neurons attenuates somatosympathetic reflex and responses to cholecystokinin. Neuroscience 2003 Abstracts 501.11. Society for Neuroscience, New Orleans, LA.

Summary: The integrity of the rostral ventrolateral medulla (RVLM) is essential for the expression of many sympathetic reflexes and the maintenance of vasomotor tone. The RVLM contains bulbospinal neurons, of which about half are catecholaminergic (C1). Destruction of bulbospinal C1 neurons leads to attenuation or abolition of the sympathetic baroreflex and chemoreflex, respectively. This study examines the effects of such destruction on blood pressure (BP), the somatosympathetic reflex and responses to intravenous (i.v) cholecystokinin (CCK) in urethane-anaesthetised, paralysed and ventilated Sprague-Dawley rats. Eighty percent of the spinally projecting C1 neurons in the RVLM were destroyed by bilateral microinjections of the immunotoxin, anti-DBH-saporin (12ng/100nl), into the intermediolateral cell column of the thoracic spinal cord (T1-2). Following treatment with the neurotoxin, systolic BP was measured for 3-5 weeks before testing the reflexes. No significant changes in systolic BP were observed. In the present study destruction of bulbospinal C1 neurons attenuated the baroreflex, replicating the findings of Schreihofer and Guyenet (2000, Am J Physiol 279:R729-R742). Activation of the somatosympathetic reflex by electrical stimulation of the tibial nerve normally elicits two peaks in averaged splanchnic sympathetic nerve activity. Following destruction of C1 neurons, the threshold voltage was reduced and the second peak was either markedly attenuated or abolished at two times threshold voltage. Intravenous injection of CCK (1, 10 and 100mg/kg) elicited depressor and sympathoinhibitory responses that were significantly reduced following destruction of bulbospinal C1 neurons. These results demonstrate a key role of bulbospinal C1 neurons in the somatosympathetic reflex and the sympathetic responses to i.v CCK but not in the tonic control of blood pressure.

Related Products: Anti-DBH-SAP (Cat. #IT-03)

Hindbrain noradrenergic lesions attenuate anorexia and alter central cFos expression in rats after gastric viscerosensory stimulation.

Rinaman L (2003) Hindbrain noradrenergic lesions attenuate anorexia and alter central cFos expression in rats after gastric viscerosensory stimulation. J Neurosci 23(31):10084-10092. doi: 10.1523/JNEUROSCI.23-31-10084.2003

Summary: Using 5-ng injections of anti-DBH-SAP (Cat. #IT-03) into hindbrain nucleus of the solitary tract in rats, the author investigated the role of DBH-positive neurons in the mediation of anorexigenic and central nervous system activation effects due to exogenous CCK.

Related Products: Anti-DBH-SAP (Cat. #IT-03)

Rostral ventrolateral medulla C1 neurons and cardiovascular regulation.

Madden CJ, Sved AF (2003) Rostral ventrolateral medulla C1 neurons and cardiovascular regulation. Cell Mol Neurobiol 23(4-5):739-749. doi: 10.1023/a:1025000919468

Summary: The authors review the use of anti-DBH-SAP (Cat. #IT-03) to study the role of C1 neurons within the rostral ventromedial medulla in cardiovascular regulation. This immunotoxin specifically removes C1 neurons containing dopamine beta-hydroxylase.

Related Products: Anti-DBH-SAP (Cat. #IT-03)

Immunotoxic destruction of distinct catecholaminergic neuron populations disrupts the reproductive response to glucoprivation in female rats.

I'Anson H, Sundling LA, Roland SM, Ritter S (2003) Immunotoxic destruction of distinct catecholaminergic neuron populations disrupts the reproductive response to glucoprivation in female rats. Endocrinology 144(10):4325-4331. doi: 10.1210/en.2003-0258

Summary: The authors hypothesized that hindbrain catcholamine neurons suppressed estrous cycles during chronic glucoprivation as an extension of their role in glucoprivic feeding. 42-ng bilateral injections of anti-DBH-SAP (Cat. #IT-03) were made into the paraventricular nucleus of female rats. Lesioned rats demonstrated inhibition of reproductive function during chronic glucose deficit, but not when a normal amount of glucose was available.

Related Products: Anti-DBH-SAP (Cat. #IT-03), Saporin (Cat. #PR-01)

Targeted toxins in pain.

Wiley RG, Lappi DA (2003) Targeted toxins in pain. Adv Drug Deliv Rev 55(8):1043-1054. doi: 10.1016/s0169-409x(03)00102-9

Summary: The authors discuss the use of 'molecular neurosurgery' in the study of nociception. Applications using targeted toxins, which include immunotoxins, protein-toxin conjugates, or peptide-toxin conjugates, are illustrated. The authors describe the use of these molecules as research tools, as well as their potential for therapeutics. A helpful table is included that lists neuronal surface markers and class of cells targeted for each targeted toxin. Reagents discussed: CTB-SAP (Cat. #IT-14), IB4-SAP (Cat. #IT-10), OX7-SAP (Cat. #IT-02), 192-Saporin (Cat. #IT-01), ME20.4-SAP (Cat. #IT-15), Anti-DBH-SAP (Cat. #IT-03), Anti-DAT-SAP (Cat. #IT-25), SP-SAP (Cat. #IT-07), Dermorphin-SAP (Cat. #IT-12), Orexin-SAP (Cat. #IT-20), CRF-SAP (Cat. #IT-13), and acetylated LDL-SAP (Cat. #IT-08).

Related Products: CTB-SAP (Cat. #IT-14), IB4-SAP (Cat. #IT-10), OX7-SAP (Cat. #IT-02), 192-IgG-SAP (Cat. #IT-01), ME20.4-SAP (Cat. #IT-15), Anti-DBH-SAP (Cat. #IT-03), Anti-DAT-SAP (Cat. #IT-25), SP-SAP (Cat. #IT-07), Dermorphin-SAP / MOR-SAP (Cat. #IT-12), Orexin-B-SAP (Cat. #IT-20), CRF-SAP (Cat. #IT-13), Acetylated LDL-SAP (Cat. #IT-08)

Long-term effects of decreased noradrenergic central nervous system innervation on pain behavior and opioid antinociception.

Jasmin L, Boudah A, Ohara PT (2003) Long-term effects of decreased noradrenergic central nervous system innervation on pain behavior and opioid antinociception. J Comp Neurol 460(1):38-55. doi: 10.1002/cne.10633

Summary: Noradrenaline (NA) is an essential element of the endogenous pain inhibitory system. The authors injected 5 µg of anti-DBH-SAP (Cat. #IT-03) into either the cerebral ventricles or lumbosacral cistern of rats to investigate whether a permanent reduction of noradrenergic innervation of the spinal cord leads to a chronic decreased nociceptive threshold. Although treated animals were less responsive to the antinociceptive effects of morphine, the results suggest that NA makes only a modest contribution to the nociceptive threshold.

Related Products: Anti-DBH-SAP (Cat. #IT-03)

Immunotoxin lesion of hypothalamically projecting norepinephrine and epinephrine neurons differentially affects circadian and stressor-stimulated corticosterone secretion.

Ritter S, Watts AG, Dinh TT, Sanchez-Watts G, Pedrow C (2003) Immunotoxin lesion of hypothalamically projecting norepinephrine and epinephrine neurons differentially affects circadian and stressor-stimulated corticosterone secretion. Endocrinology 144(4):1357-1367. doi: 10.1210/en.2002-221076

Summary: Hindbrain norepinephrine (NE) and epinephrine (E) neurons are important in the distribution of internal sensory signals. Injecting 42 ng of anti-DBH-SAP (Cat. #IT-03) into the paraventricular nucleus of rat hypothalamus, the authors were able to specifically destroy NE and E neurons. This study revealed the contribution of NE/E afferents to hypothalamo-pituitary-adrenal activation during stress and confirmed that NE and E neurons are required for specific stress responses.

Related Products: Anti-DBH-SAP (Cat. #IT-03)

Immunolesion of norepinephrine and epinephrine afferents to medial hypothalamus alters basal and 2-deoxy-D-glucose-induced neuropeptide Y and agouti gene-related protein messenger ribonucleic acid expression in the arcuate nucleus.

Fraley GS, Ritter S (2003) Immunolesion of norepinephrine and epinephrine afferents to medial hypothalamus alters basal and 2-deoxy-D-glucose-induced neuropeptide Y and agouti gene-related protein messenger ribonucleic acid expression in the arcuate nucleus. Endocrinology 144(1):75-83. doi: 10.1210/en.2002-220659

Summary: Neuropeptide Y (NPY) and agouti gene-related protein (AGRP) are important peptides in the control of food intake. Prior studies have shown that mRNAs for both these peptides are increased in the arcuate nucleus of the hypothalamus (ARC) by glucoprivation. Using bilateral 42 ng intracranial injections of anti-DBH-SAP (Cat. #IT-03) in rats, the authors investigated the role of hindbrain catecholamine afferents in this increased ARC NPY and AGRP gene expression. The results indicate that these afferents contribute to basal NPY and AGRP gene expression as well as mediate the responsiveness of NPY and AGRP neurons to glucose deprivation.

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Immunotoxic lesions of ascending catechoalminergic afferents abolish the CRH gene transcriptional response to 2-deoxyglucose in the rat paraventricular nucleus

Watts AG, Sanchez-Watts G, Dinh TT, Ritter S (2002) Immunotoxic lesions of ascending catechoalminergic afferents abolish the CRH gene transcriptional response to 2-deoxyglucose in the rat paraventricular nucleus. Neuroscience 2002 Abstracts 865.2. Society for Neuroscience, Orlando, FL.

Summary: CRH neurons in the medial parvicellular (mp) part of the paraventricular nucleus (PVH) are critical for the neural control of the hypothalamo-pituitary-adrenal axis. One of their most prominent afferents sets derives from hindbrain catecholaminergic neurons that are thought to help mediate viscerosensory influences on the PVHmp. Despite the prominence of this input, its precise role in controlling CRH neuronal function remains controversial. Here we report the effect on basal and stimulated CRH gene expression of an immunotoxin that selectively destroys catecholaminergic neurons. Rats were injected in the PVH with either a saporin-anti-dopamine B-hydroxylase (DBH) conjugate (DSAP), which leads to total loss of DBH immunoreactivity in the PVH, or saporin alone (SAP), which does not. Three weeks later, animals were injected either with 250mg/kg of 2-deoxy-D-glucose (2DG) or vehicle. Thirty mins later they were anesthetized and perfused with 4% buffered paraformaldehyde. Fifteen um frozen sections were cut through the hypothalamus and hybridized for CRH mRNA, CRH hnRNA, or c-fos mRNA. DSAP treatment had no effect on CRH mRNA levels in the PVH of vehicle- or 2DG-injected animals, but abolished the CRH hnRNA and c-fos mRNA responses to 2DG. We have reported elsewhere that DSAP lesions selectively abolish the corticosterone response to 2DG, but not to swim stress, or circadian corticosterone release. We now show that catecholaminergic afferents are required for 2DG-induced CRH gene expression, but not for basal expression.

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Immunotoxic lesion of catecholamine afferents to paraventricular hypothalamus (PVH) impairs the corticosterone response to glucoprivation but not the basal secretory rhythm or response to swim stress

Ritter S, Dinh TT, Pedrow C, Roellich K (2002) Immunotoxic lesion of catecholamine afferents to paraventricular hypothalamus (PVH) impairs the corticosterone response to glucoprivation but not the basal secretory rhythm or response to swim stress. Neuroscience 2002 Abstracts 865.4. Society for Neuroscience, Orlando, FL.

Summary: Catecholamine afferents from the hindbrain densely innervate the medial parvicellular part of the PVH, which contains CRH neurons critical for control of corticosterone (CORT) secretion. However, the precise role of these afferents in control of CORT secretion is unclear. Here the immunotoxin, saporin conjugated to anti-dopamine B-hydroxylase(DSAP), which selectively lesions norepinephrine and epinephrine neurons, or unconjugated saporin (SAP) control solution, was microinjected into the PVH. After extensive habituation to testing conditions, DSAP and SAP rats were injected with 2-deoxy-D-glucose (2DG, 250mg/kg) or vehicle or subjected to a 5-min forced swim. Blood was sampled remotely between 0 and 240 min for radioimmunoassay of CORT. In a third test, blood was sampled every 4 hr for 24 hr to assess the basal secretory rhythm of CORT. Subsequently, loss of dopamine B-hydroxylase containing terminals without destruction of CRH neurons in the PVH of DSAP rats was confirmed by immunohistochemistry. In DSAP rats, the CORT response to 2DG was reduced dramatically to 29% of the response in SAP controls. In contrast, DSAP and SAP rats did not differ in their basal secretory rhythm or their CORT response to swim stress, indicating for the first time a stimulus-specific role of catecholamine afferents in control of CORT secretion. This finding is complemented by other work in which we (with A.G. Watts and G. Sanchez-Watts) show that these catecholamine afferents are required for 2DG-induced CRH gene expression, but not basal expression.

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Role of hindbrain catecholaminergic afferents to the medial hypothalamus in the regulation of penile reflexes in the rat

Fraley GS (2002) Role of hindbrain catecholaminergic afferents to the medial hypothalamus in the regulation of penile reflexes in the rat. Neuroscience 2002 Abstracts 681.4. Society for Neuroscience, Orlando, FL.

Summary: The use of ex copula erections, or reflexive erections, has been used for decades in the study of the central pathways and neuroendocrinology of penile erections. However, the exact neuroendocrine pathways involved in developing penile erections are not known. This study utilized molecular neurosurgical techniques combined with behavioral, histological, and molecular analyses to determine a central link between metabolic state and penis erectile function. Utilizing saporin-conugate immunolesion techniques (DSAP), hindbrain catecholaminergic afferents to the hypothalamus that are reported to be glucoresponsive were eliminated. DSAP-lesioned rats had a significantly attenuated glucoprivic feeding response and significantly attenuated penile reflexes compared to controls. Analysis of Nissl-stained spinal cord sections demonstrated a significant reduction in the size of sexually dimorphic motoneurons. Furthermore, qualitative analysis of calcitonin gene-related immunoreactivity (CGRPir) in alternate spinal sections revealed a decrease in CGRPir in sexually dimorphic motor pools. Analysis of hypothalamic mRNA levels showed a significant increase in both oxytocin and neuropeptide Y mRNA, but not b-actin mRNA. No significant differences were seen, however, in the weight of the perineal muscles, seminal vessicles, or in plasma testosterone levels. These data indicate a novel hindbrain-hypothalamic-spinal cord pathway by which potential glucoresponsive neurons effect the ability to achieve penile erection based upon availability of metabolic fuel.

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Simultaneous neurotoxic lesions of noradrenergic LC, histaminergic TMN and cholinergic BF neurons do not elicit hypersomnia whereas lesions of the hypocretin-containing LH neurons do.

Blanco-Centurion CA, Gerashchenko D, Murillo-Rodriguez E, Shiromani PJ (2002) Simultaneous neurotoxic lesions of noradrenergic LC, histaminergic TMN and cholinergic BF neurons do not elicit hypersomnia whereas lesions of the hypocretin-containing LH neurons do. Neuroscience 2002 Abstracts 577.16. Society for Neuroscience, Orlando, FL.

Summary: Wakefulness is believed to be due to activation of neurons in the locus coeruleus (LC), tuberomammillary nucleus (TMN) and the basal forebrain (BF). These neurons receive a heavy projection from hypocretin (HCRT) neurons. It has been proposed that the HCRT neurons maintain wakefulness via their innervation of these three groups of neurons. Here we test this hypothesis by lesioning the LC, TMN and the BF. Sprague-Dawley rats implanted with sleep recording electrodes were given microinjections of the following saporin neurotoxins to lesion specific neurons: α-DBH-saporin (vol=0.4 μL; 1 μg/μL, LC lesion) , HCRT2-saporin (vol=0.4 μL; 0.20 μg/μL, TMN lesion) and 192IgG-saporin (vol=0.5 μL; 0.4 μg/μL, BF lesion). Six rats given saline injections served as controls. Immediately after surgery sleep recordings were made continuously for three weeks. In rats that had double lesions (n=7)(combinations of LC, TMN or BF) sleep was not increased. In two rats the LC, TMN and BF were destroyed (>95%) but there was no hypersomnia either. However, one rat that had a triple lesion and also had 30% loss of HCRT neurons showed significant and persistent hypersomnia. Previously, lesion of a single wake-active neuronal population has not been found to increase sleep. We have now found that double or triple lesions also do not produce hypersomnia. Only when the HCRT neurons are lesioned, sleep is affected. This suggests that HCRT neurons play a primary role in waking and the LC, TMN or BF neurons do not mediate this function.

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The dyssynaptic pathway from the caudal ventrolateral medulla to the spinal cord is relevant for pain modulation

Tavares I, Cobos AR, Almeida A, Lima D (2002) The dyssynaptic pathway from the caudal ventrolateral medulla to the spinal cord is relevant for pain modulation. Neuroscience 2002 Abstracts 351.21. Society for Neuroscience, Orlando, FL.

Summary: The caudal ventrolateral medulla (VLM) exerts α2-adrenoreceptor mediated inhibition of pain transmission at the spinal cord. Anatomical studies described a dysynaptic pathway, connecting the VLM with the spinal cord through the A5 noradrenergic cell group, in which the spinally-projecting A5 noradrenergic neurons give collaterals to the VLM. In order to evaluate the role of the VLM-A5-spinal pathway in pain modulation, retrograde transport of the neurotoxin saporin-anti-dopamine-β-hydroxylase (SAP-anti-DBH) from the VLM was used. The VLM of Wistar rats was injected with 0.5μl of a 1% SAP-anti-DBH solution or saline (control group). Four days later, all animals were injected with 50 μl of 5% formalin in the ipsilateral hindpaw, and pain behavior and noxious-evoked spinal c-fos expression, were evaluated. In the SAP-anti-DBH group, a 27% decrease in DBH-immunoreactive neuronal population at the A5 noradrenergic cell group was detected and neuronal death was confirmed by Fluojade staining. Hyperalgesia was detected in the second phase of the formalin test. The numbers of Fos-immunoreacted neurons in the spinal dorsal horn increased. The data suggest that the VLM-A5-spinal pathway participates in pain modulation. It remains to be ascertained whether the lack of effect at the first-phase of the formalin test is due to an insufficient destruction of the A5 noradrenergic cell group or whether it points to a differential effect of this pathway in the two phases of the formalin test.

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Long-term effects on pain behavior of decreased spinal noradrenaline in neuropathic rats

Ohara PT, Boudah A, Jasmin L (2002) Long-term effects on pain behavior of decreased spinal noradrenaline in neuropathic rats. Neuroscience 2002 Abstracts 351.22. Society for Neuroscience, Orlando, FL.

Summary: We sought to determine if a permanent reduction in the noradrenergic (NA) input to the spinal cord in adult rats would alter the pain behavior associated with nerve injury. Selective NA denervation of the lumbo-sacral cord was achieved by intrathecal injection of anti-dopamine beta-hydroxylase antibodies conjugated to the toxin saporin in 12 female rats. Spinal NA denervation was confirmed histologically in all animals. Saline injected rats served as controls. Two weeks after toxin or saline treatment, a unilateral peripheral neuropathy was induced by tight ligation of the left L5 spinal nerve in both groups. Unexpectedly, the same degree of mechanical hyperalgesia was present in the neuropathic paw of rats in both the toxin and saline treated groups. Rats lacking NA spinal afferents, however, were less responsive to the antinoiceptive effects of morphine administered systemically or intracerebroventricularly. Also, toxin treated rats did not display opioid dependant stress analgesia. Finally, toxin treated rats were more responsive to the antinociceptive effect of the NK1 antagonist CP 96,345 but not to its enantiomer CP 96,344. From these results we conclude that the permanent loss of spinal NA does not alter neuropathic pain behavior, possibly because of compensatory changes in the CNS. The decreased response to opioids is consistent with the previous suggestions of an interaction between noradrenergic and opioidergic systems in producing analgesia. The increased response to NK1 antagonists shows that NA tonically inhibits substance.

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Immunotoxin lesion of spinally projecting catecholamine neurons impairs the adrenal medullary response to glucoprivation and the sympathetic response to forced swim

Dinh TT, Duffy P, Ritter S (2002) Immunotoxin lesion of spinally projecting catecholamine neurons impairs the adrenal medullary response to glucoprivation and the sympathetic response to forced swim. Neuroscience 2002 Abstracts 76.5. Society for Neuroscience, Orlando, FL.

Summary: Distinct populations of hindbrain catecholamine neurons project spinally to innervate sympathetic and adrenal medullary preganglionic neurons. Previously we injected the immunotoxin, saporin conjugated to anti-dopamine beta hydroxylase (DSAP), into the spinal cord to selectively lesion these neurons. DSAP lesions abolished adrenal medullary Fos expression following insulin-induced hypoglycemia or 2-deoxy-D-glucose (2DG) and eliminated the hyperglycemic response to 2DG, which is mediated by adrenal medullary epinephrine (E) secretion. Here we examine the plasma E and norepinephrine (NE) responses to 2DG (250 mg/kg, s.c.) and to 5 min of forced swim in rats injected at T2-T4 with DSAP or unconjugated saporin (SAP) control solution. Blood was sampled remotely via jugular catheters between 0 and 240 min after 2DG or swim. Immunohistochemistry confirmed loss of dopamine B-hydroxylase throughout the spinal cord of DSAP rats. In DSAPs, both plasma E and hyperglycemic responses to 2DG were abolished or severely impaired compared to SAPs. 2DG did not elevate plasma NE in either group. Swim stress increased NE in both SAPs and DSAPs, but the DSAP response was only 60% of the SAP response. Results show for the first time that the selective activation of the adrenal medulla by glucoprivation, described previously, is mediated by spinally projecting catecholamine neurons. Results also demonstrate that spinal catecholamine terminals, presumeably arising from different hindbrain neurons, contribute to, but are not entirely responsible for, sympathetic neuronal responses to swim stress.

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Selective lesioning of the developing cholinergic and noradrenergic systems: Anatomical, neurochemical and functional effects

Leanza G, Cataudella T (2002) Selective lesioning of the developing cholinergic and noradrenergic systems: Anatomical, neurochemical and functional effects. FENS 2002 Abstracts 151.12. Federation of European Neuroscience Societies, Paris, France.

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Immunotoxic catecholamine lesions attenuate 2DG-induced increase of AGRP mRNA.

Fraley GS, Dinh TT, Ritter S (2002) Immunotoxic catecholamine lesions attenuate 2DG-induced increase of AGRP mRNA. Peptides 23(6):1093-1099. doi: 10.1016/s0196-9781(02)00044-x

Summary: The authors investigated mRNA levels of both agouti gene-related protein (AGRP) and neuropeptide Y (NPY) in rats after lesioning the PVH with anti-DBH-SAP (42 ng in 200 nl, Cat. #IT-03). The results show that the increase in AGRP mRNA levels due to 2DG administration was completely blocked.

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Alpha-7 nicotinic receptor expression by two distinct cell types in the dorsal raphe nucleus and locus coeruleus of rat.

Bitner RS, Nikkel AL (2002) Alpha-7 nicotinic receptor expression by two distinct cell types in the dorsal raphe nucleus and locus coeruleus of rat. Brain Res 938:45-54. doi: 10.1016/s0006-8993(02)02485-x

Summary: Neuronal nicotinic acetylcholine receptors (nAChRs) are suspected to play a role in neurophysiological disorders such as schizophrenia, Alzheimer’s disease, and epilepsy. Whereas the molecular and cellular properties of these receptors have been well characterized, the role of nAChRs in the nervous system is as yet unclear. The authors injected rats intracerebroventricularly with 5 µg/5 µl of anti-DBH-SAP (Cat. #IT-03) to eliminate the noradrenergic nuclei. Using these data along with data acquired by elimination of serotonergic nuclei with 5,7-DHT, the authors showed that both noradrenergic nuclei in the locus coeruleus and serotonergic nuclei in the dorsal raphe nucleus express the alpha-7 nAChR subunit.

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Spinal noradrenergic activation mediates allodynia reduction from an allosteric adenosine modulator in a rat model of neuropathic pain.

Li X, Conklin D, Ma W, Zhu X, Eisenach JC (2002) Spinal noradrenergic activation mediates allodynia reduction from an allosteric adenosine modulator in a rat model of neuropathic pain. Pain 97:117-125. doi: 10.1016/s0304-3959(02)00011-8

Summary: T62 is a thiobene compound that enhances adenosine agonist binding to the A1 receptor. Activation of the adenosine receptor has been effective in several different pain models. The authors used a spinal nerve ligation model for mechanical allodynia to assess T62 efficacy and mode of action. Rats treated with anti-DBH-SAP (4 µg in 5 µl, Cat. #IT-03) experienced no anti-allodynia effects from T62 administration, indicating that modulation of mechanical allodynia by T62 utilizes the spinal noradrenergic system.

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Isoflurane and nociception: Spinal alpha2A adrenoceptors mediate antinociception while supraspinal alpha1 adrenoceptors mediate pronociception.

Kingery WS, Agashe GS, Guo TZ, Sawamura S, Davies MF, Clark JD, Kobilka BK, Maze M (2002) Isoflurane and nociception: Spinal alpha2A adrenoceptors mediate antinociception while supraspinal alpha1 adrenoceptors mediate pronociception. Anesthesiol 96:367-374. doi: 10.1097/00000542-200202000-00023

Summary: The authors injected 3 µg/3 µl of anti-DBH-SAP (Cat. #IT-03) into the lateral ventricle of rats to determine whether noradrenergic brainstem nuclei and descending spinal pathways are responsible for the antinociceptive actions of isoflurane. The results indicate that isoflurane modulates nociception by as many as three mechanisms, utilizing various combinations of noradrenergic neurons, adrenoceptors, and descending spinal pathways.

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Colocalization of mu-opioid receptors and activated G-proteins in rat cingulate cortex.

Vogt LJ, Sim-Selley LJ, Childers SR, Wiley RG, Vogt BA (2001) Colocalization of mu-opioid receptors and activated G-proteins in rat cingulate cortex. J Pharmacol Exper Ther 299:840-848.

Summary: The anterior cingulate cortex (ACC) is a primary site of opiate drug action, and much of this activity is associated with the m-opioid receptor (MOR). The mechanisms by which MOR regulates pain in the ACC are not well understood. Using anti-DBH-SAP (7 µg into left lateral ventricle in rat; Cat. #IT-03) the authors mapped MOR activity in the ACC and evaluated the histochemical and behavioral relationships between MOR binding and mu-receptor-activated G-proteins after lesioning.

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Novel method for localized, functional sympathetic nervous system denervation of peripheral tissue using guanethidine.

Demas GE, Bartness TJ (2001) Novel method for localized, functional sympathetic nervous system denervation of peripheral tissue using guanethidine. J Neurosci Methods 112:21-28. doi: 10.1016/s0165-0270(01)00452-6

Summary: Sympathectomy, or surgical interruption of sympathetic nerve pathways, is an important technique in the analysis of the sympathetic nervous system. The authors investigate and compare several different methods of performing a sympathectomy in hamsters, including surgery, chemical, and immunotoxic lesions using anti-DBH-SAP (ten 2-µl injections, at either 0.65 µg/µl or 0.325 µg/µl, into inguinal white adipose tissue; Cat. #IT-03).

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Selective immunotoxin lesion of spinally projecting norepineprhine and epinephrine (NE/E) neurons impairs the glucagon response to 2-deoxy-d-glucose (2DG).

Dinh TT, Sanders NM, Pedrow C, Ritter S (2001) Selective immunotoxin lesion of spinally projecting norepineprhine and epinephrine (NE/E) neurons impairs the glucagon response to 2-deoxy-d-glucose (2DG). Neuroscience 2001 Abstracts 947.1. Society for Neuroscience, San Diego, CA.

Summary: Previous work has shown that the targeted immunotoxin, anti-dopamine ß-hydroxylase conjugated to saporin (DSAP), can be used to selectively destroy subpopulations of hindbrain NE/E neurons projecting to or through a particular DSAP injection site. Using this approach, we have shown that NE/E neurons projecting to the hypothalamus are required for feeding and glucocorticoid responses to 2DG-induced glucoprivation and those projecting spinally are required for the adrenal medullary response. In this study, we injected DSAP or unconjugated saporin (SAP) control solution into the spinal cord at T2-T4 to investigate the role of the spinally projecting NE/E neurons in glucagon secretion induced by 2DG (250 mg/kg). Controls injected spinally with unconjugated saporin (SAP) had a glucagon response that peaked at 308% of pre-2DG levels, while DSAP-injected rats had a significantly blunted response to 2DG, peaking at 197% of pre-2DG levels. 2DG-induced hyperglycemia also was impaired in the DSAP rats, but not in the SAP rats. Both SAP and DSAP rats had normal feeding and glucocorticoid responses to 2DG. Results suggest that spinally-projecting NE/E neurons participate in the neural control of glucagon secretion under conditions of glucose deficit. In combination with other findings, these results indicate that hindbrain NE/E neurons contribute to four major glucoregulatory responses (increased feeding, and increased secretion of glucagon, glucocorticoids and adrenal medullary epinephrine) through their projections to hypothalamic or spinal cord effector sites.

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Immunotoxin lesion of catecholaminergic neurons innervating the medial hypothalamus elevates basal expression of and attenuates glucoprivaation-induced increases in agouti gene related protein (AGRP) mRNA.

Fraley GS, Dinh TT, Ritter S (2001) Immunotoxin lesion of catecholaminergic neurons innervating the medial hypothalamus elevates basal expression of and attenuates glucoprivaation-induced increases in agouti gene related protein (AGRP) mRNA. Neuroscience 2001 Abstracts 947.2. Society for Neuroscience, San Diego, CA.

Summary: Catecholaminergic (CA) innervation of medial hypothalamic structures is necessary for glucoprivation-induced feeding, glucocorticoid secretion and Fos expression in the paraventricular (PVH) and arcuate nuclei of the hypothalamus. In this experiment, we tested the hypothesis that the 2-deoxy-D-glucose (2DG)-induced an increase in AGRP mRNA expression (reported recently by Sergeyev et al., 2000) also requires NE/E neurons. CA neurons innervating the medial hypothalamus were lesioned using the toxin, saporin, targeted for selective entry into NE/E neurons by conjugation with a monoclonal antibody against dopamine beta hydroxylase. This toxin (DSAP), or unconjugated saporin (SAP) control solution, was bilaterally microinjected into the PVH. DSAP rats with confirmed 2DG-induced feeding deficits (DSAP 1.7 +/- 0.29 g; SAP 5.1 +/- 0.31 g; p < 0.05) and controls were injected with 2DG (250 mg/kg), or saline and maintained for 2 hrs without food. Hypothalami were harvested and subjected to Northern blot analysis of AGRP mRNA. Blot analysis revealed that 2DG increased mRNA expression in SAP controls (2DG: 1.0 +/- 0.05 RDU; saline: 0.7 +/- 0.02, p< .05), but not in DSAP lesioned rats (2DG: 1.1 +/- 0.04; saline: 1.0 +/- 0.03). In addition, basal AGRP mRNA expression was significantly elevated in DSAP-lesioned rats compared to SAP controls (p < .05). These data suggest that basal AGRP gene expression is controlled by hindbrain CA neurons and that increased AGRP gene expression induced by glucoprivation also requires these neurons.

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Selective immunotoxin lesion of hypothalamically-projecting norepinephrine/epinephrine (NE/E) neurons impairs the glucocorticoid response to glucoprivation.

Ritter S, Dinh TT, Sanders NM, Pedrow C (2001) Selective immunotoxin lesion of hypothalamically-projecting norepinephrine/epinephrine (NE/E) neurons impairs the glucocorticoid response to glucoprivation. Neuroscience 2001 Abstracts 947.3. Society for Neuroscience, San Diego, CA.

Summary: Decreased glucose utilization triggers behavioral and neuroendocrine responses that increase blood glucose concentrations and delivery of glucose to the brain. These include stimulation of food intake and increased secretion of glucagon, adrenal E and glucocorticoids. In previous work utilizing the targeted immunotoxin, DSAP (saporin conjugated to a monoclonal antibody against dopamine β-hydroxylase), we demonstrated that hindbrain NE/E neurons that project to the hypothalamus are necessary for glucoprivic feeding and those that project spinally are necessary for glucoprivic control of adrenal medullary secretion. In the present study, we injected DSAP or control solution into the paraventricular nucleus of the hypothalamus (PVH) to investigate the role of NE/E neurons in glucoprivic control of glucocorticoid secretion. DSAP lesions significantly attenuated the magnitude and duration of the glucocorticoid (cortisol) response to 2-deoxy-D-glucose (2DG)-induced glucoprivation, but did not reduce the glucagon response. After 2DG (250 mg/kg), cortisol levels peaked at only 184% of pre-2DG levels in DSAP rats, compared to 440% in controls. Quantitative analysis revealed that DSAP did not destroy CRF-immunoreactive cell bodies in the PVH or terminals in the arcuate/median eminence, but did reduce dopamine β-hydroxylase immunoreactivity in hypothalamus and in hindbrain NE/E cell groups known to innervate the hypothalamus, including those that innervate CRF neurons in the PVH. Results indicate a critical role for hindbrain NE/E neurons in eliciting multiple controls of glucose homeostasis.

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Monoamine modulation of spinal reflex excitability of the lower limb in the rat: Intrathecal infusion (i.t.) of anti-DBH saporin toxin – time course for behavior.

Bose P, Wang DC, Parmer R, Wiley RG, Thompson FJ (2001) Monoamine modulation of spinal reflex excitability of the lower limb in the rat: Intrathecal infusion (i.t.) of anti-DBH saporin toxin – time course for behavior. Neuroscience 2001 Abstracts 771.3. Society for Neuroscience, San Diego, CA.

Summary: Progressive neurophysiological changes in the excitability of ankle extensor stretch reflexes were observed following T8 spinal cord contusion injury. Our previous study indicated that nonspecific monoamine depletion (reserpine, i.p.)contributed to pathologic hyperreflexia. To test a more specific hypothesis, a longitudinal study was performed to evaluate the time course of changes in reflex excitability after i.t. injection of 250ng of anti-DBH saporin toxin (that specifically lesions descending spinal noradrenergic neurons) into the lumbar spinal cord of normal rats. Measures of ankle torque and time-locked EMGs were used to scale stretch reflex excitability across a broad range of stretch velocities (49-612°/sec) before and at weekly intervals following i.t. injection of toxin (n=12) or vehicle (n=6) using instrumentation and protocol previously reported. An elevated pattern of ankle toque was noted in all velocities tested on day 1 and week 1 of toxin treated animals compared with vehicle controls. By week-2, and for the remaining 5 weeks of testing, significant elevation of the ankle torque was only observed in the faster velocities. Significant increases in hindlimb axis and base of support were also observed from footprint analysis. These findings indicate that selective lesion of spinal noradrenergic fibers produced some of the specific changes in the reflex excitability that were observed following midthoracic spinal contusion injury.

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Monoamine modulation of spinal reflex excitability of the lower limb in the rat: Intrathecal (i.t.) infusion of anti-DBH saporin toxin – time course for neurophysiology.

Wang DC, Bose P, Parmer R, Wiley RG, Thompson FJ (2001) Monoamine modulation of spinal reflex excitability of the lower limb in the rat: Intrathecal (i.t.) infusion of anti-DBH saporin toxin – time course for neurophysiology. Neuroscience 2001 Abstracts 771.5. Society for Neuroscience, San Diego, CA.

Summary: Progressive neurophysiological changes in the excitability of ankle extensor stretch reflex were identified following T8 spinal cord contusion injury (Thompson et. al., 1992). Previous study suggested that nonspecific monoamine depletion may be a significant contributor to the pathologic hyperreflexia associated with chronic spinal cord injury (Thompson et. al., 1999). To test a more specific hypothesis, a study was performed to evaluate the time course of changes in reflex excitability after i.t. injection of 250ng of anti-DBH saporin toxin to specifically lesion descending spinal noradrenergic neurons into the lumbar spinal cord of normal rats. Measures of H-reflex excitability were obtained prior to and at weekly intervals following toxin injection until a physiological plateau was observed. Significant decreases in rate-depression of H-reflexes were observed by the second week after toxin infusion and were maintained throughout the five weeks of testing. These studies indicate that selective lesioning of noradrenergic fibers produced specific changes in reflex excitability previously observed following midthoracic spinal cord contusion injury in the rat. The results of this study further implicate neurophysiological changes associated with monoamine loss as a contributing factor leading to hyperreflexia derived from chronic spinal cord injury. Correlated behavioral changes are reported in the companion poster, Bose et.al.

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Selective immunotoxin lesions of hindbrain norepinephrine/epinephrine (NE/E) neurons impair feeding and corticosterone responses and Fos-immunoreactivity in hypothalamic sites during insulin-induced hypoglycemia (IIH).

Sanders NM, Dinh TT, Pedrow C, Ritter S (2001) Selective immunotoxin lesions of hindbrain norepinephrine/epinephrine (NE/E) neurons impair feeding and corticosterone responses and Fos-immunoreactivity in hypothalamic sites during insulin-induced hypoglycemia (IIH). Neuroscience 2001 Abstracts 635.21. Society for Neuroscience, San Diego, CA.

Summary: Previously,we used the targeted immunotoxin saporin, conjugated to a monoclonal antibody against dopamine Beta-hydroxylase(DSAP),to destroy hypothalamic projecting NE/E neurons. Results showed that NE/E neurons are required for 2-deoxy-D-glucose induced feeding and Fos expression in the hypothalamus. In the present study,we used this same technique to determine if NE/E neurons play a similar role in mediating IIH responses.Rats were injected with DSAP or unconjugated saporin (SAP)into the hypothalamic paraventricular nucleus(PVH).Insulin reduced blood glucose to similar values in DSAP and SAP rats(15 and 17mg/dl, respectively). Glucagon responses to hypoglycemia were unaffected by DSAP,peaking at 597% and 504% of pre-drug levels after insulin in DSAP and SAP rats,respectively.In contrast,the corticosterone response was severely diminished in DSAP rats,peaking at only 123% of pre-insulin levels, compared to 353% in SAP rats.DSAP injections also abolished the feeding response to IIH.DSAP rats ate 0.9g of food during IIH while the SAP rats at 6.1g of food.DBH-ir was abolished in the A1/C1 overlap and reduced in A2,C2,C3 and A6 sites in DSAP rats. In the SAP rats,IIH induced Fos-ir in hindbrain NE/E neurons the PVH, LH and ARC.In DSAP rats, Fos-ir was reduced or abolished in these hypothalamic sites but was preserved in the adrenal medulla.These findings further support the role of hindbrain NE/E neurons in transmitting information from hindbrain glucoreceptive sites to hypothalamic circuits coordinating feeding and neuroendocrine responses to glucose deficit.

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Immunolesioning of brainstem DBH neurons on the mating-induced LH and prolactin surge in the rabbit.

Pau K (2001) Immunolesioning of brainstem DBH neurons on the mating-induced LH and prolactin surge in the rabbit. Neuroscience 2001 Abstracts 466.7. Society for Neuroscience, San Diego, CA.

Summary: Coitus induces a surge release of norepinephrine (NE) that is accompanied by a preovulatory gonadotropin-releasing hormone (GnRH)/luteinizing hormone (LH) surge. Prazosin, an alpha-1 adrenergic antagonist, attenuates the GnRH/LH surge, and tyrosine hydroxylase (TH) gene expression in brainstem NE areas increases within 30 min after coitus. Here, we determined the coitus-induced LH/prolactin surge after specific lesioning of dopamine beta-hydroxylase (DBH) neurons in the brainstem with monoclonal anti-DBH sera conjugated with the ribosomal cytotoxin saporin (DBH-SAP). Female NZW rabbits received 3rd cerebroventricular injection (Day 0) of either DBH-SAP (20 µg, n=4) or SAP (3 µg, n=4). On day 14, the four DBH-SAP females were paired with stud males, but none of them mated. After daily injection of estradiol benzoate (EB, 3 µg) for 3 days, all eight females mated. Blood samples were taken once before, and at 10-min intervals for 4 hours after, coitus. Brainstems were prepared for immunocytochemical detection of DBH and TH. Coitus increased both LH and prolactin release in either DBH-SAP or SAP animals. However, postcoital LH and prolactin levels were 55% lower and 50% higher, respectively, in DBH-SAP rabbits than in SAP animals. The number of DBH neurons was near zero in the A6 and reduced by 80% in the A1 and 70% in the A2 noradrenergic areas in DBH-SAP animals. The number of TH neurons was reduced by 95% and 30% in the A6 and A1 areas, respectively, and did not change in the A2 area. The results suggest that the presence of intact brainstem NE neurons are critical for sexual performance and production of normal LH/prolactin surge after coitus in female rabbits.

Related Products: Anti-DBH-SAP (Cat. #IT-03)

Noradrenergic inputs to the paraventricular nucleus (PVN) is involved in estrogen receptor α expression in the PVN of 48-h fasted and 2DG-injected female rats.

Estacio MA, Tsukamura H, Reyes BA, Maeda KI (2001) Noradrenergic inputs to the paraventricular nucleus (PVN) is involved in estrogen receptor α expression in the PVN of 48-h fasted and 2DG-injected female rats. Neuroscience 2001 Abstracts 409.6. Society for Neuroscience, San Diego, CA.

Summary: Involvement of noradrenergic inputs to the paraventricular nucleus (PVN) in estrogen receptor α (ERα) expression in the PVN during 48-h fasting and 2DG-induced glucoprivation in female rats was determined by examining the effect of destroying the noradrenergic inputs to the PVN using the saporin-conjugated anti-dopamine-β-hydroxylase (anti-DBH-saporin). Ovariectomized rats were injected bilaterally with anti-DBH-saporin in the PVN. After two weeks, animals were either fasted for 48 hours or injected intravenously with 2DG, then perfused with 4% paraformaldehyde. Brain sections were processed for ERα and DBH immunocytochemistry. Forty-eight-hour fasting or 2DG injection siginificantly increased the number of ERα-immunoreactive (ERα-ir) cells in the PVN in control animals. Anti-DBH-saporin injection prevented fasting- or 2DG-induced increase in ERα-ir cells in the PVN. The DBH-ir axons in the parvocellular PVN were severely reduced following anti-DBH-saporin injection in both fasted and 2DG injected rats. Among the brainstem noradrenergic cell groups examined, there was a significant decrease in the number of DBH-ir cells in the A2 region of both fasted and 2DG injected rats treated with anti-DBH-saporin. There was no obvious reduction in the number of DBH-ir cells in the A1 and A6 regions in the anti-DBH-saporin-injected fasted- or 2DG-injected rats. The results suggest that the A2 noradrenergic input to the PVN plays a major role in increasing ERα expression in the PVN in response to 48-h fasting or 2DG-induced glucoprivation.

Related Products: Anti-DBH-SAP (Cat. #IT-03)

A novel method for localized sympathetic nervous system denervation of peripheral tissue using guanethidine.

Bartness TJ, Demas GE (2001) A novel method for localized sympathetic nervous system denervation of peripheral tissue using guanethidine. Neuroscience 2001 Abstracts 309.10. Society for Neuroscience, San Diego, CA.

Summary: A simple technique for the functional deactivation of the sympathetic nervous system innervation of peripheral tissues is described using the local application of guanethidine. Multiple unilateral microinjections of guanethidine were made into one inguinal or epididymal white adipose tissue (IWAT and EWAT) pads of hamsters, whereas the contralateral pad received equivolumetric saline vehicle injections. Guanethidine treatment virtually abolished the sympathetic innervation of both EWAT and IWAT, as measured by the absence of significant norepinephrine (NE) tissue content two weeks later and as suggested by the two-fold increase in IWAT mass characteristic of surgically induced WAT denervation. IWAT and EWAT NE content and mass were unaffected in the contralateral control pads. Guanethidine injections into the spleen also lead to a function sympathectomy as indicated by significant depletions of NE content. Because guanethidine treatment did not decrease body mass nor induce ptosis, no chemical-induced malaise or global sympathetic denervation, respectively, was suggested. We compared the effects of local guanethidine treatment on IWAT NE content and pad mass with the local application of the sympathetic neurotoxin, anti-dopamine beta hydroxylase saporin, and with local surgical IWAT denervation. Guanethidine treatment significantly reduced IWAT NE content to a greater degree than for the alternative sympathectomy methods. These results suggest that locally applied, chemical sympathectomy with guanethidine provides an effective, restricted method for denervating WAT and likely other peripheral tissues.

Related Products: Anti-DBH-SAP (Cat. #IT-03)

Targeted destruction of A2/C2 catecholamine neurons alters hypothalamic responses to vagal stimulation.

Rinaman L, Wonders CP (2001) Targeted destruction of A2/C2 catecholamine neurons alters hypothalamic responses to vagal stimulation. Neuroscience 2001 Abstracts 131.4. Society for Neuroscience, San Diego, CA.

Summary: Central catecholamine (CA) pathways participate in viscerosensory modulation of hypothalamic neuroendocrine function. Different brainstem CA cell groups may relay different types of viscerosensory signals to different classes of hypothalamic effectors. The present study sought to determine the role of dorsal medullary A2/C2 neurons in hypothalamic responses to exogenous cholecystokinin (CCK), which activates gastrointestinal vagal sensory inputs to the caudal brainstem. Saporin toxin conjugated to dopamine-beta-hydroxylase antibody (anti-DbH-sap; 10 ng in 100 nl) or control toxin was microinjected unilaterally or bilaterally into the A2/C2 region of the dorsal vagal complex in adult male rats. After 10-14 days, rats were injected i.p. with CCK (10 ug/kg) and perfused with fixative 1 hr later. Brainstem and forebrain sections were processed for dual immunocytochemical detection of cFos (a marker of neural activation) and DbH (to define the lesion). Additional forebrain sections were processed for cFos and either oxytocin (OT), vasopressin (AVP), or corticotropin-releasing factor (CRF) to identify hypothalamic neurons activated by CCK. Anti-DbH-sap destroyed the majority of A2/C2 neurons within the microinjection site(s), with minimal non-specific damage. A2/C2 lesions markedly attenuated CCK-induced activation of OT neurons and, to a lesser extent, attentuated CRF activation. Conversely, CCK-induced cFos expression was significantly increased in AVP neurons. The latter effect was observed only after bilateral lesions. These results indicate that A2/C2 neurons participate in vagal sensory-mediated stimulation of OT neurons and CRF neurons, and inhibition of AVP neurons.

Related Products: Anti-DBH-SAP (Cat. #IT-03)

Long-term intrathecal catheterization in the rat.

Jasmin L, Ohara PT (2001) Long-term intrathecal catheterization in the rat. J Neurosci Methods 110:81-89. doi: 10.1016/s0165-0270(01)00420-4

Summary: The authors have developed a method that allows repeated administration of drugs with minimal stress to an experimental animal. To test the efficacy of this intrathecal catheter, they injected anti-DBH-SAP (5 µg; Cat. #IT-03,) and investigated the noradrenergic denervation of the spinal cord. All animals treated with anti-DBH-SAP showed extensive loss of spinal noradrenergic ennervation. Even three months after catheter implantation, the elimination of noradrenergic neurons in the spinal cord could be produced. This indicates the intrathecal catheter is an effective tool for the study of multiple-dose drug delivery.

Related Products: Anti-DBH-SAP (Cat. #IT-03)

Transneuronal tracing from sympathectomized lumbar epaxial muscle in female rats.

Daniels D, Miselis RR, Flanagan-Cato LM (2001) Transneuronal tracing from sympathectomized lumbar epaxial muscle in female rats. J Neurobiol 48(4):278-290. doi: 10.1002/neu.1057

Summary: The authors use pseudorabies virus (PRV) to study central neural networks such as the one controlling the lordosis reflex (increased curvature of the spine). To aid in the separation of the sympathetic nervous system and higher order systems, rats were treated with lumbar injections of anti-DBH-SAP (156 ng to 5 µg; Cat. #IT-03), then labeled with PRV. PRV labeling in the brain was absent in areas associated with vasomotor tone, but persisted in areas implicated in control of the lordosis response.

Related Products: Anti-DBH-SAP (Cat. #IT-03)

It’s enough to raise your blood pressure!

Deuchars J, Deuchars S (2001) It's enough to raise your blood pressure!. Trends Neurosci 24(4):200. doi: 10.1016/s0166-2236(00)01800-2

Summary: The authors review studies completed by Schreihofer and Guyenet using anti-DBH-SAP (Cat. #IT-03) to eliminate C1 adrenergic neurons. The results show that, although C1 neurons play a role in some sympathoexcitatory responses, they are probably not responsible for maintaining sympathetic tone.

Related Products: Anti-DBH-SAP (Cat. #IT-03)

Immunotoxic destruction of distinct catecholamine subgroups produces selective impairment of glucoregulatory responses and neuronal activation.

Ritter S, Bugarith K, Dinh TT (2001) Immunotoxic destruction of distinct catecholamine subgroups produces selective impairment of glucoregulatory responses and neuronal activation. J Comp Neurol 432(2):197-216. doi: 10.1002/cne.1097

Summary: Control of regulatory responses to low glucose levels in the brain have been linked to catecholaminergic neurons. Studies of these neurons have been hindered by the lack of a selective and precise lesioning agent. Ritter et al. use anti-DBH-SAP (Cat. #IT-03) to create very precise lesions of catecholamine neurons in the paraventricular nucleus of the hypothalamus and spinal cord. Injection of anti-DBH-SAP into the spinal cord eliminates cells with caudal projections while injection into the paraventricular nucleus of the hypothalamus eliminated cells with rostral projections. This ability to selectively eliminate very specific subpopulations of cells is a valuable characteristic in dissecting neuronal function.

Related Products: Anti-DBH-SAP (Cat. #IT-03)

Antinociceptive action of nitrous oxide is mediated by stimulation of noradrenergic neurons in the brainstem and activation of a2B adrenoceptors.

Sawamura S, Kingery WS, Davies MF, Agashe GS, Clark JD, Kobilka BK, Hashimoto T, Maze M (2000) Antinociceptive action of nitrous oxide is mediated by stimulation of noradrenergic neurons in the brainstem and activation of a2B adrenoceptors. J Neurosci 20(24):9242-9251. doi: 10.1523/JNEUROSCI.20-24-09242.2000

Summary: Nitrous oxide has been used extensively in surgical anesthesia for more than 150 years, but the molecular mechanism of action has not yet been defined. Sawamura et al. investigate whether noradrenergic neurons in the brainstem are involved in the analgesic action of nitrous oxide. The authors injected rats with anti-DBH-SAP (Cat. #IT-03) to destroy pontine noradrenergic neurons. The treated rats demonstrated the usual sedative effects of nitrous oxide, but the analgesic effects were reduced or blocked. Coupled with data from null mice for the alpha2B adrenoceptor, the data indicates that alpha2 adrenoceptor subtypes and ligands are involved in the analgesic but not sedative effects of nitrous oxide.

Related Products: Anti-DBH-SAP (Cat. #IT-03)

Neuronal lesioning with axonally transported toxins.

Wiley RG, Kline IV RH (2000) Neuronal lesioning with axonally transported toxins. J Neurosci Methods 103:73-82. doi: 10.1016/S0165-0270(00)00297-1

Summary: Functional neuroanatomy studies have long utilized lesioning. Given the complexity of heterogeneous neuron populations conventional lesioning methods have proved relatively crude, and have provided limited information. Wiley and Kline detail some of the immunotoxins utilizing saporin as well as neuropeptide-saporin conjugates that have found use in recent neurological research. These products include SP-SAP (Cat. #IT-07), which eliminates neurons expressing the neurokinin 1 receptor, 192-Saporin (Cat. #IT-01), which eliminates neurons expressing the p75 receptor in rats, anti-DBH-SAP (Cat #IT-03), which destroys noradrenergic and adrenergic neurons, and OX7-SAP (Cat. #IT-02), which is a suicide transport agent targeting all rat neurons. The authors also discuss some of the protocols and methods utilized with these compounds.

Related Products: 192-IgG-SAP (Cat. #IT-01), OX7-SAP (Cat. #IT-02), Anti-DBH-SAP (Cat. #IT-03), SP-SAP (Cat. #IT-07)

Intracortical injection of DBH-saporin targets noradrenergic axons in the medial prefrontal cortex of the rat.

Mazei MS, Wiley RG, Deutch AY (2000) Intracortical injection of DBH-saporin targets noradrenergic axons in the medial prefrontal cortex of the rat. Neuroscience 2000 Abstracts 639.8. Society for Neuroscience, New Orleans, LA.

Summary: The medial prefrontal cortex (mPFC) is innervated by both dopaminergic and noradrenergic neurons. While the densities of the two types of catecholamine axons are different in subregions of the mPFC, axons of both types are present in most of the mPFC. The goal of this study was to selectively lesion noradrenergic axons in the rat mPFC while sparing dopaminergic axons, using microinjection of the immunotoxin dopamine β-hydroxylase (DBH)-saporin. DBH-saporin (10- 100 ng/μ1) was unilaterally injected into three brain regions, the mPFC, caudate-putamen (CP) and cerebellum. Rats were sacrificed 2-10 days post-injection and the lesion was characterized by tyrosine hydroxylase (TH), DBH, and norepinepherine transporter (NET) immunohistochemistry. DBH-saporin administration resulted in discrete lesions. There appeared to be a decrease in the number of immunoreactive (ir) axons after DGH-saporin infusion into the mPFC: surviving axons were swollen and dystrophic. However, the effect of DBH-saporin appears more pronounced when examining DBH-ir than with NET-ir. Intrastriatal injections of DBH-saporin did not decrease TH-ir, suggesting that dopaminergic axons were spared. Since DBH-saporin acts by entry into DBH-containing vesicles, a longer time course may be necessary to observe loss of the NET marker than DBH. Studies are in progress to examine this possibility.

Related Products: Anti-DBH-SAP (Cat. #IT-03)

DBH-saporin lesions the locus coeruleus, but does not produce cataplexy or abnormal REM sleep triggering.

Blanco-Centurion CA, Salin-Pascual R, Gerashchenko D, Greco MA, Lappi DA, Kilduff TS, Shiromani PJ (2000) DBH-saporin lesions the locus coeruleus, but does not produce cataplexy or abnormal REM sleep triggering. Neuroscience 2000 Abstracts 566.17. Society for Neuroscience, New Orleans, LA.

Summary: Recently, canine narcolepsy was associated with a mutation in the hypocretin-2 receptor (Lin et al., 1999), which binds the neuropeptide hypocretin, also known as orexin. The locus coeruleus receives a very heavy projection of HCRT/OX fibers, and the LC also contains HCRT/OX receptor mRNA. Silence of LC neurons is hypothesized to be key in triggering cataplexy and REM sleep. To test this hypothesis, DBH-saporin was used to selectively lesion the LC. Male Sprague-Dawley rats (400-450 g) instrumented for recording sleep were given DBH-saporin (n=4) (500ng/0.5ul) via a micropipette to the LC. Control rats were administered 192-saporin (n=3), or saline (n=4). Two days later, sleep recordings were obtained for 7 consecutive days. The rat's behavior was videotaped at night. To identify whether cataplexy was induced, the alpha antagonist, Prazosin was administered (1500h, 500mg/kg, IP) and then sleep and video recordings were made for three hours. Brains were removed for histology. DBH-saporin completely lesioned the LC neurons. However, there were no changes in wakefulness, nonREM or REM sleep. Video recordings also did not reveal any cataplexy episodes. The application of Prazosin did not induce cataplexy or diminish muscle tone in DBH-saporin LC treated rats. Historically, LC lesions have never been found to induce cataplexy. Use of DBH-saporin provides a more specific lesion restricted to the LC neurons where the HCRT/OX receptor mRNA is localized. Our findings indicate that LC neurons are not essential for maintaining muscle tone or wakefulness.

Related Products: Anti-DBH-SAP (Cat. #IT-03)

Anti-dβh-saporin injection into the paraventricular nucleus of the hypothalamus selectively abolishes 2DG-induced feeding without causing nonspecific tissue destruction.

Ritter S, Dinh TT, Bugarith K (2000) Anti-dβh-saporin injection into the paraventricular nucleus of the hypothalamus selectively abolishes 2DG-induced feeding without causing nonspecific tissue destruction. Neuroscience 2000 Abstracts 502.8. Society for Neuroscience, New Orleans, LA.

Summary: The toxin-antibody complex, saporin conjugated to a monoclonal antibody against dopamine-β-hydroxylase (anti-dβh-sap), selectively destroys dβh-containing catecholamine neurons. Previously we reported that PVH anti-dβh-sap injections abolish feeding and expression of Fos-immunoreactivity (-ir) in the PVH in response to 2DG-induced glucoprivation and cause selective destruction of dβh-containing neurons innervating the hypothalamus. To test the behavioral and neurochemical specificity of this lesion, anti-dβh-sap or control solution (saline or unconjugated saporin) was injected bilaterally into the PVH (n=6 per group). Beginning three weeks later, rats were tested for stimulation of feeding by 2-deoxy-D-glucose (2DG, 200 mg/kg) and mercaptoacetate (MA, 68 mg/kg), which reduce glucose and fatty acid oxidation, respectively, and for suppression of feeding by cholecystokinin octapeptide (CCK, 4 ug/kg). 2DG-induced feeding was abolished by anti-dβh-sap injection, but was not impaired by unconjugated saporin. Neither MA nor CCK responses were altered by anti-dβh-sap. The nonspecific toxicity of anti-dβh-sap at the injection site was assessed. We found that PVH magnocellular neurons at the injection site express oxytocin-ir and do not appear to be disrupted by the anti-βh-sap injection. Further, the ability of PVH neurons at the injection site to express Fos in response to a non-glucoprivic stimulus was not impaired by anti-dβh-sap since lateral ventricular injection of senktide, an NK3 receptor agonist, induced Fos ir in the PVH. PVH injections of anti-dβh-sap impair 2DG-induced feeding and PVH Fos expression by selective destruction of catecholamine neurons. PHS#DK 40498.

Related Products: Anti-DBH-SAP (Cat. #IT-03)

Regulation of sympathetic vasomotor tone and arterial pressure by the rostral ventrolateral medulla after elimination of C1 neurons in rat.

Schreihofer AM, Stornetta RL, Guyenet PG (2000) Regulation of sympathetic vasomotor tone and arterial pressure by the rostral ventrolateral medulla after elimination of C1 neurons in rat. Neuroscience 2000 Abstracts 310.7. Society for Neuroscience, New Orleans, LA.

Summary: The rostral ventrolateral medulla (RVLM) tonically stimulates sympathetic preganglionic neurons to maintain arterial pressure (AP). Although the C1 neurons in the RVLM may have a sympathoexcitatory function, it is not known whether they are the essential presympathetic RVLM neurons. In the present study, we selectively destroyed spinally projecting C1 cells (∼84%) with bilateral microinjections (spinal segments T2-T3) of an anti-dopamine-betahydroxylase antibody conjugated to saporin (anti-DβH-SAP). 3-5 weeks later these rats had a normal AP and splanchnic nerve activity (SNA) under chloralose anesthesia. Extracellular recording and juxtacellular labeling of bulbospinal barosensitive neurons in RVLM revealed that after anti-DβH-SAP only the lightly myelinated RVLM neurons with no or very low levels of tyrosine hydroxylase immunoreactivity were preserved. In these rats, inhibition of RVLM (muscimol 100 pmol/100 nl/side) eliminated SNA and decreased AP as seen in control rats. However, treatment with anti-DβHSAP reduced the sympathoexcitatory and pressor responses to electrical stimulation in RVLM. Although treatment with anti-DβH-SAP also eliminated A5 noradrenergic cells, rats with selective lesions of A5 cells (local microinjection of 6-hydroxydopamine) displayed no deficits to stimulation of the RVLM. These data suggest basal sympathetic vasomotor tone relies primarily on non-catecholaminergic presympathetic cells in the RVLM. In contrast, bulbospinal adrenergic neurons are important for the increased SNA and AP produced by stimulation of the RVLM.

Related Products: Anti-DBH-SAP (Cat. #IT-03)

Distribution of mu-opioid receptors and activated G-proteins in rat cingulate cortex and alterations following removal of noradrenergic afferents.

Vogt LJ, Sim-Selley LJ, Childers SR, Wiley RG, Vogt BA (2000) Distribution of mu-opioid receptors and activated G-proteins in rat cingulate cortex and alterations following removal of noradrenergic afferents. Neuroscience 2000 Abstracts 238.1. Society for Neuroscience, New Orleans, LA.

Summary: Anterior cingulate cortex (ACC) is involved in acute and chronic pain processing. Here we define opioid architecture throughout rat cingulate cortex, relate mu-opioid receptor and G-protein stimulated binding in particular layers, and localize binding to noradrenergic terminals with immunotoxin lesions (anti-DBH-saporin). [3H]DAMGO binding was highest in areas 32 and 24 with a peak in layer I. Midcingulate area 24' and posterior area 29 had lower and homogeneous binding. DAMGO stimulated [35S]GTPγS binding in area 24' was similar to that in areas 32 and 24, while area 29 had very low and homogeneous binding. Undercut lesions reduced [3H]DAMGO binding in all layers with greatest loss in layer I, while DAMGO-stimulated [35S]GTPγS binding losses occurred only in layers I-III. Since neurons in the midline thalamic nuclei and locus coeruleus synthesize mu-opioid receptors, noradrenergic afferents were removed with anti-DBH-saporin. This toxin reduced [3H]DAMGO binding only in layer I of areas 32 and 24, while DAMGO-stimulated [35S]GTPγS binding increased in layer II of areas 32 and 24, had no changes in area 24', and decreased binding in layer I of area 29. Thus, in addition to their actions on ACC neurons, other sites of opiate drug actions are through mu-opioid heteroreceptors on glutamatergic thalamic and noradrenergic locus coeruleus afferents to ACC.

Related Products: Anti-DBH-SAP (Cat. #IT-03)

Chronic noradrenergic spinal denervation in rats does not produce long-term hyperalgesia.

Jasmin L, Arsenault P, Ohara PT, Marchand S (2000) Chronic noradrenergic spinal denervation in rats does not produce long-term hyperalgesia. Neuroscience 2000 Abstracts 243.7. Society for Neuroscience, New Orleans, LA.

Summary: Pharmacological studies have established that noradrenaline tonically inhibits spinal nociceptive transmission. We tested the hypothesis that chronically decreasing spinal noradrenaline would result in a disinhibition of nociceptive afferents resulting in behavioral hyperalgesia. We destroyed noradrenergic cells innervating the spinal cord using dopamine beta-hydroxylase antibodies linked to the neurotoxin saporin (anti-DBH-Sap). Male rats (n=6) were injected intrathecally with 4µg/10µl of anti-DBH-Sap, and their responses to nociceptive and non-nociceptive stimuli was monitored over a period of 65 days. Compared to controls (n=6), a significant (p< 0.05) decrease to hot plate (46oC) nociceptive responses could be observed during the first week post-treatment, but no differences were found at later times. At no point was there any altered response to innocuous stimuli. When tested for response to cold water stress, both treated and control animals showed analgesia, demonstrating that descending pain inhibition could still be activated. At 65 days, a formalin test showed no difference between treated (1.1 +/-0.5) and control (0.8 +/-0.5) groups. Post-mortem immunostaining of spinal cords for DBH, however, confirmed that noradrenergic denervation of the spinal cord had occurred in treated animals. These results suggest that a reorganization of the spinal cord following noradrenergic denervation is sufficient to reestablish normal nociceptive responses.

Related Products: Anti-DBH-SAP (Cat. #IT-03)

Altered operant and reflex responses to noxious heat in rats with central noradrenergic lesions using antiDßH-saporin.

Vierck CJ, Belford PM, Iqbal MA, Camara C, Kline RH, Lappi DA, Wiley RG (2000) Altered operant and reflex responses to noxious heat in rats with central noradrenergic lesions using antiDßH-saporin. Neuroscience 2000 Abstracts 247.10. Society for Neuroscience, New Orleans, LA.

Summary: We sought to determine effects of a selective lesion of pontine NA neurons on thermal sensitivity, using an operant escape task and hotplate tests. 8 rats received ICV injections of 10 ìg of anti-DβH-saporin, an immunotoxin that selectively destroys NA neurons, or vehicle. The rats were trained to escape a dark chamber with a hot floor to a brightly lit room-temperature shelf. There was no difference between groups at 39o, 44oor 47o C. However, at 44o C, application of mustard oil to the dorsal surface of both hindpaws or 0.94% capsaicin cream to the plantar surfaces increased escape durations only for vehicle rats. Also, at 44o C, toxin-treated rats were more sensitive than vehicle rats to morphine (0.5-5 mg/kg, s.c.) and clonidine (0.125 mg/kg, s.c.). The toxin-injected rats were insensitive to yohimbine (2.5 and 5 mg/kg, s.c.). Postmortem analysis for DβH showed that toxin-treated rats lost all pontine NA neurons, with preservation of medullary NA cells. To determine the role of NA projections to the spinal cord, two groups of rats were injected with 200-300 ng of antiDβH-saporin or vehicle via a lumbar intrathecal catheter. There were no consistent changes in baseline responses, and no differences between toxin and vehicle injected rats to 44o C after capsaicin or morphine (2.5 mg/kg, s.c.). However, the toxin treated rats were more sensitive to clonidine (0.03 mg/kg, s.c.). Thus, spinally projecting NA neurons appear not to mediate some modulatory effects of pontine NA neurons on nociception.

Related Products: Anti-DBH-SAP (Cat. #IT-03)

Immunohistochemical detection of alpha-7 nicotinic receptor expression by two distinct cell types in the dorsal raphe and locus coeruleus of rat.

Bitner RS, Nikkel AL, Decker MW (2000) Immunohistochemical detection of alpha-7 nicotinic receptor expression by two distinct cell types in the dorsal raphe and locus coeruleus of rat. Neuroscience 2000 Abstracts 41.7. Society for Neuroscience, New Orleans, LA.

Summary: The α7 nicotinic acetylcholine receptor (nAChR) subunit can be assembled to form a homomeric-pentamer with high permeability to calcium, in contrast to other neuronal nAChR subunit-comprised ligand-gated cation channels. Although the expression of the α7-nAChR has been demonstrated throughout the CNS, the neurochemical phenotype of neurons expressing α7 remains to a large extent unknown. Using a polyclonal antibody raised against the carboxyl terminus (amino acids 460-479) of the α7 nAChR subunit (goat IgG, Santa Cruz Biotech.), immunohistochemical staining was observed in rat dorsal raphe (DR) and locus coeruleus (LC), serotonergic and noradrenergic brainstem nuclei, respectively. In both the DR and LC, there appeared to be two histologically distinct α7-expressing cell types as distinguished by size, i.e. large vs. small diameter. In rats treated with either a selective serotonergic (5,7-dihydroxytryptamine 150 μg i.c.v.) or noradrenergic (anti-dopamine-β-hydroxylase saporin 5 μg i.c.v.) neurotoxin, α7 immunostaining was seen only in small diameter cells, suggesting that the large diameter α7-expressing cells were serotonergic DR and noradrenergic LC neurons. Indeed, double-labeling experiments revealed in the large, but not small, cell types coexpression of α7 with tryptophan hydroxylase in the DR and tyrosine hydroxylase in the LC of saline-treated rats. In contrast, there was no coexpression in the neurotoxin-treated rats due to the loss of serotonergic or noradrenergic neurons, with only small diameter α7-expressing cells remaining. The results of these studies suggest that both serotonergic and noradrenegic neurons express α7 nAChRs. In addition, there appears to be a small diameter, non-serotonergic/noradrenergic cell-type in both the DR and LC that also expresses α7.

Related Products: Anti-DBH-SAP (Cat. #IT-03)

Local immunotoxin treatment prevents transneuronal labeling of the intermediolateral column; but not the ventral horn; of the spinal cord after tracer injection into lumbar epaxial muscle.

Daniels D, Miselis RR, Flanagan-Cato LM (2000) Local immunotoxin treatment prevents transneuronal labeling of the intermediolateral column; but not the ventral horn; of the spinal cord after tracer injection into lumbar epaxial muscle. Neuroscience 2000 Abstracts 77.13. Society for Neuroscience, New Orleans, LA.

Summary: Pseudorabies virus (PRV) has been used as a transneuronal tracer to study central neural circuits that control various peripheral targets. Our laboratory has injected PRV into the lumbar epaxial muscles that produce the lordosis posture to label sequentially specific brain regions along the neuraxis. However, concomitant uptake of PRV through sympathetic innervation of nearby vasculature has made the interpretation of higher-order labeling problematic. To avoid this confound, we have designed a procedure for focal sympathetic denervation using dopamine-β-hydroxylase immunotoxin (DHIT). Five days after injecting DHIT (5 μg) into the medial portion of lateral longissimus, the Bartha strain of PRV was injected into the pre-treated area. After survival times of 72 or 96 h, animals were sacrificed and the spinal cords were immunostained for PRV. In preliminary studies, DHIT treatment was not effective in all animals, as determined by PRV labeling in the sympathetic preganglionic neurons that reside in IML. However, at each survival time, in 50% of the animals DHIT virtually eliminated PRV-labeling in cells within IML of the thoracic and lumbar spinal cord, whereas robust labeling of motoneurons in the ventral horn was retained. These preliminary results suggest that this procedure for local sympathectomy may allow for selective transneuronal labeling of somatic motor pathways.

Related Products: Anti-DBH-SAP (Cat. #IT-03)

Regulation of sympathetic tone and arterial pressure by rostral ventrolateral medulla after depletion of C1 cells in rat.

Schreihofer AM, Stornetta RL, Guyenet PG (2000) Regulation of sympathetic tone and arterial pressure by rostral ventrolateral medulla after depletion of C1 cells in rat. J Physiol 529(1):221-236. doi: 10.1111/j.1469-7793.2000.00221.x

Summary: The rostral ventrolateral medulla (RVLM) controls and maintains basal sympathetic vasomotor tone, and is also vital to many sympathetic reflexes. Sympathetic nerve activity and arterial pressure correlate with the C1 adrenergic neurons in the RVLM, but there are also non-catecholaminergic neurons present. Schreihofer et al. used anti-DBH-SAP (Cat. #IT-03) to eliminate the C1 cells of the RVLM to investigate the non-catecholaminergic neuron contribution to vasomotor tone. Their data indicate C1 cells are necessary for full expression of sympathoexitatory responses generated by the RVLM.

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Role of presympathetic C1 neurons in the sympatholytic and hypotensive effects of clonidine in rats.

Schreihofer AM, Guyenet PG (2000) Role of presympathetic C1 neurons in the sympatholytic and hypotensive effects of clonidine in rats. Am J Physiol Regul Integr Comp Physiol 279:R1753-R1762. doi: 10.1152/ajpregu.2000.279.5.R1753

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Brainstem noradrenergic control of nociception is abnormal in the spontaneously hypertensive rat.

Taylor BK, Roderick RE, Basbaum AI (2000) Brainstem noradrenergic control of nociception is abnormal in the spontaneously hypertensive rat. Neurosci Lett 291:139-142. doi: 10.1016/s0304-3940(00)01389-6

Usage: anti-DBH-SAP (Cat. #IT-03), 5 µg

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Sympathetic reflexes after depletion of bulbospinal catecholaminergic neurons with anti-DBH-saporin.

Schreihofer AM, Guyenet PG (2000) Sympathetic reflexes after depletion of bulbospinal catecholaminergic neurons with anti-DBH-saporin. Am J Physiol Regul Integr Comp Physiol 279:R729-R742. doi: 10.1152/ajpregu.2000.279.2.R729

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Immunolocalization of the cocaine- and antidepressant-sensitive 1-norepinephrine transporter.

Schroeter S, Apparsundaram S, Wiley RG, Miner LH, Sesack SR, Blakely RD (2000) Immunolocalization of the cocaine- and antidepressant-sensitive 1-norepinephrine transporter. J Comp Neurol 420:211-232. doi: 10.1002/(SICI)1096-9861(20000501)420:2<211::AID-CNE5>3.0.CO;2-3

Summary: Norepinephrine transporters are involved in the response to multiple antidepressants and psychostimulants, but the expression of these proteins has not yet been characterized in the central nervous system. Schroeter et al. used an antibody to a cytoplasmic epitope of norepinephrine transporters to map the transporters to noradrenergic neuronal somata, axons, and dendrites. To verify the specificity of the antibody the researchers injected 10 µg of anti-DBH-SAP (Cat. #IT-03) in the left lateral ventricle of rats to destroy the noradrenergic neurons, confirming the specificity of the norepinephrine transporter antibody. Treatment with anti-DBH-SAP completely removed norepinephrine transporter immunoreactivity.

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Abolition of cyanide-induced sympathoexcitation by selective lesion of bulbospinal catecholaminergic neurons

Schreihofer AM, Guyenet PG (1999) Abolition of cyanide-induced sympathoexcitation by selective lesion of bulbospinal catecholaminergic neurons. Neuroscience 1999 Abstracts 474.6. Society for Neuroscience, MIami, FL.

Summary: The rostral ventrolateral medulla (RVLM) contains BS C1 adrenergic cells and non-CA neurons whose relative importance for the production of sympathetic vasomotor tone and cardiovascular reflexes remains unknown. In the present study we evaluate 2 sympathetic reflexes after selective lesions of BS CA neurons with the neurotoxin saporin-anti-dopamine beta hydroxylase (SAP-DBH). Rats received bilateral microinjections of SAP-DBH (42 ng/200nl/site) into the spinal cord centered at the intermediolateral cell column at T2 & T4 & T6 and were allowed to recover for 3-5 weeks. Arterial pressure (AP), heart rate (HR), and splanchnic nerve activity (SNA) were measured while the rats were chloralose-anesthetized, artificially ventilated, and paralyzed. Baseline AP and HR were comparable between control rats (n-7, 113 +/- 7 mmHg, 426 +/- 12 bpm) and lesioned rats (n=7, 123 +/- 4 mmHg, 448 +/- 7 bpm). In control rats stimulation of the carotid chemoreflex (100 micrograms/kg sodium cyanide, iv) produced a burst in SNA (266 +/- 26%) followed by inhibition (to 18 +/- 3% of base). In contrast, in the SAP-DBH-treated animals cyanide produced only an inhibition of SNA (to 33 +/- 7% of base). Mean AP responses mirrored the SNA responses. In contrast, the Bezold-Jarisch reflex was not diminished in the SAP-DBH-treated rats. Phenyl biguanide (5 micrograms/kg, iv) decreased AP (22 +/- 3 vs. 42 +/- 5 mmHg), SNA (85 +/- 4 vs. 67 +/- 6%), and HR (28 +/- 6 vs. 56 +/- 7 bpm) in control rats and lesioned rats respectively. Histological examination revealed that SAP-DBH depleted the vast majority of BS C1 cells (>70% of the rostral third of the C1 cell group), and >80% of the A5 cell group. These results indicate that sympathetic vasomotor tone persists and rats have a normal mean AP in the absence of most of BS C1 and A5 cells. Although the BS C1 cells may not be required for the Bezold-Jarisch reflex, BS CA cells are essential for the sympathoexcitatory response to cyanide. Work supported by NIH 28785.

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Lesions of the C1 catecholaminergic neurons of the ventrolateral medulla in rats using anti-DBH-saporin.

Madden CJ, Ito S, Rinaman L, Wiley RG, Sved AF (1999) Lesions of the C1 catecholaminergic neurons of the ventrolateral medulla in rats using anti-DBH-saporin. Am J Physiol 46:R1063-R1075. doi: 10.1152/ajpregu.1999.277.4.R1063

Summary: The authors review the use of anti-DBH-SAP (Cat. #IT-03) to study the role of C1 neurons within the rostral ventromedial medulla in cardiovascular regulation. This immunotoxin specifically removes C1 neurons containing dopamine beta-hydroxylase.

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Differential effects of neurotoxic destruction of descending noradrenergic pathways on acute and persistent nociceptive processing.

Martin WJ, Gupta NK, Loo CM, Rohde DS, Basbaum AI (1999) Differential effects of neurotoxic destruction of descending noradrenergic pathways on acute and persistent nociceptive processing. Pain 80:57-65. doi: 10.1016/s0304-3959(98)00194-8

Summary: The authors used Anti-DBH-SAP to re-examine the contribution of noradrenergic pathways to nociception and to morphine analgesia. They also evaluated morphine analgesia in the formalin test and found that toxin-treated animals exhibited enhanced morphine analgesia. These results establish the utility of using this immunotoxin to selectively destroy subpopulations of noradrenergic cell groups and provide evidence that acute and persistent nociception are differentially regulated by descending noradrenergic pathways.

Usage: Intrathecal treatment with Anti-DBH-SAP attenuates formalin pain (5.0 µg/20 µl).

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Activation of coeruleospinal noradrenergic inhibitory controls during withdrawal from morphine in the rat.

Rohde DS, Basbaum AI (1998) Activation of coeruleospinal noradrenergic inhibitory controls during withdrawal from morphine in the rat. J Neurosci 18(11):4393-4402. doi: 10.1523/JNEUROSCI.18-11-04393.1998

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Destruction of locus coeruleus neuronal perikarya after injection of anti-dopamine-beta-hydroxylase immunotoxin into the olfactory bulb of the rat.

Blessing WW, Lappi DA, Wiley RG (1998) Destruction of locus coeruleus neuronal perikarya after injection of anti-dopamine-beta-hydroxylase immunotoxin into the olfactory bulb of the rat. Neurosci Lett 243:85-88. doi: 10.1016/s0304-3940(98)00090-1

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Methods of sympathetic degeneration and alteration.

Picklo MJ (1997) Methods of sympathetic degeneration and alteration. J Auton Nerv Syst 62:111-125. doi: 10.1016/s0165-1838(96)00121-x

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Central noradrenergic lesioning using anti-DBH-saporin: anatomical findings.

Wrenn CC, Picklo MJ, Lappi DA, Robertson DR, Wiley RG (1996) Central noradrenergic lesioning using anti-DBH-saporin: anatomical findings. Brain Res 740:175-186. doi: 10.1016/s0006-8993(96)00855-4

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Lesioning of medullary noradrenergic and adrenergic neurons using the immunotoxin anti-DBH-saporin.

Wrenn CC, Picklo MJ, Lappi DA, Robertson D, Wiley RG (1996) Lesioning of medullary noradrenergic and adrenergic neurons using the immunotoxin anti-DBH-saporin. Neuroscience 1996 Abstracts 749.15. Society for Neuroscience, Washington, DC.

Summary: Anti-DBH-saporin (α-DBH-sap) is an anti-neuronal immunotoxin comprised of an antibody against the noradrenaline synthesizing enzyme dopamine β-hydroxylase (DBH) coupled by a disulfide bond to the ribosome inactivating toxin saporin. This immunotoxin was injected into the left lateral ventricle of rats at doses of 5, 10, and 20 μg. After a two week survival time, the rats were sacrificed and the ability of the immunotoxin to lesion noradrenergic and adrenergic neurons was assessed by immunohistochemical staining for tyrosine hydroxylase (TH), DBH, and phenylethanolamine n-methyl transferase (PNMT). The locus coeruleus was completely lesioned at all three doses. The A5 and A7 cell groups were completely lesioned at the two higher doses. In the medulla, lesioning of the ventrolateral Al/Cl cell group and the dorsomedial A2/C2/C3 cell group was qualitatively observed to be incomplete at all three doses. Cell counts of TH+, DBH+, and PNMT+ neurons revealed that the number of neurons staining for each enzyme was reduced by the immunotoxin dose dependently. The ventrolateral population was lesioned more closely to completeness than the dorsomedial population. These data show that α-DBH-sap can be used to produce lesions of brainstem noradrenergic and adrenergic neurons. Supported by the Department of Veterans Affairs.

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Anti-dopamine beta-hydroxylase immunotoxin-induced sympathectomy in adult rats.

Picklo MJ, Wiley RG, Lonce S, Lappi DA, Robertson D (1995) Anti-dopamine beta-hydroxylase immunotoxin-induced sympathectomy in adult rats. J Pharmacol Exp Therap 275(2):1003-1010.

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Noradrenergic lesioning with an anti-dopamine beta-hydroxylase immunotoxin.

Picklo MJ, Wiley RG, Lappi DA, Robertson D (1994) Noradrenergic lesioning with an anti-dopamine beta-hydroxylase immunotoxin. Brain Res 666:195-200. doi: 10.1016/0006-8993(94)90772-2

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Noradrenergic lesioning using anti-DBH immunotoxin

Picklo MJ, Wiley RG, Lappi DA, Robertson D (1993) Noradrenergic lesioning using anti-DBH immunotoxin. Neuroscience 1993 Abstracts 771.10. Society for Neuroscience, Washington, DC.

Summary: Current methods of lesioning noradrenergic neurons have significant drawbacks due either to incompleteness, partial specificity, or reversibility. We sought to determine if an immunotoxin to dopamine ß-hydroxylase (DBH) would efficiently destroy noradrenergic neurons in vivo. The MAB3O8 monoclonal antibody to bovine DBH was obtained from Chemicon International (Temecula, CA). Antibody was disulfide coupled to the ribosome inactivating protein, saporin, using SPDP. The resulting immunotoxin was injected into anesthetized adult, male Sprague-Dawley rats. Injection sites in individual animals were the submandibular gland (3.1-12.5 µg), intravenous (6-31 µg), and intraventricular (1.8-4.8 µg). Three days after systemic injections, rats were reanesthetized and transcardially perfused with aldehyde fixative. Frozen sections of peripheral ganglia were processed for Nissi staining. In sections from sympathetic ganglia, most neurons showed severe chromatolysis characteristic of the cytotoxic effect of immunotoxins containing saporin. Sensory ganglia showed small numbers of similarly poisoned neurons. Eleven days after intraventricular injections, rats were sacrificed and brain sections stained either with cresyl violet (N¡ssl) or for tyrosine hydroxylase (TH) using indirect immunoperoxidase technique. Nissi staining of the locus coeruleus showed a decrease in the numbers of neurons as was confirmed by staining for TH. Dopaminergic neurons in the midbrain appeared unaffected as did catecholaminergic neurons in the caudal brainstem. We conclude that anti-DBH-saporin efficiently destroys noradrenergic neurons in the CNS and PNS. This immunotoxin may be a valuable lesioning tool with greater selectivity than has been previously available.

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Soluble and membrane-bound forms of dopamine b-hydroxylase are encoded by the same mRNA.

Lewis EJ, Asnani LP (1992) Soluble and membrane-bound forms of dopamine b-hydroxylase are encoded by the same mRNA. J Biol Chem 267:494-500. doi: 10.1016/S0021-9258(18)48522-5

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