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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)
2-deoxy-D-glucose (2DG) increases NPY mRNA expression in hindbrain neurons
Li AJ, Ritter S (2003) 2-deoxy-D-glucose (2DG) increases NPY mRNA expression in hindbrain neurons. Neuroscience 2003 Abstracts 615.7. Society for Neuroscience, New Orleans, LA.
Summary: Previous results suggest that the orexigenic peptide, neuropeptide Y (NPY), participates in glucoprivic feeding. NPY mRNA in the hypothalamus is increased by glucoprivation (Sergeyev et al, 2000; Fraley and Ritter, 2003) and injection of anti-NPY antibody into the paraventricular nucleus of the hypothalamus (PVH) impairs glucoprivic feeding (He and Edwards, 1998). The hypothalamus is innervated by both arcuate and hindbrain NPY cell bodies. NPY innervation from the hindbrain is substantial and is derived largely or entirely from cell bodies that co-express norepinephrine or epinephrine. Selective immunotoxin lesions have demonstrated that these hindbrain catecholamine neurons are required for glucoprivic feeding (Ritter et al., 2001), as well as for glucoprivic stimulation of corticosterone secretion (Ritter et al., 2003) and suppression of estrus (I’Anson et al., 2003). However, the specific contribution of hindbrain NPY to these glucoregulatory responses has not been examined. Therefore, we examined NPY mRNA expression in hindbrain catecholamine cell groups 1.5 hr after 2-deoxy-D-glucose (2DG, 250 mg/kg) injection using in situ hybridization. Cell groups A1, A1/C1, the middle portion of C1 and C2, showed a basal level of NPY mRNA signal that was dramatically increased by 2DG. In rostral C1 and in C3, where basal NPY mRNA expression was below detection threshold, the hybridization signal was also significantly increased by 2DG. In cell groups A2, A5, A6 and A7, neither basal nor 2DG-stimulated NPY mRNA expression was detected. PVH microinjection of the retrogradely transported catecholamine immunotoxin, saporin conjugated to anti-dopamine-β-hydroxylase, destroyed hindbrain catecholamine neurons and abolished basal and 2DG-stimulated increases in NPY expression in hindbrain cell groups. These data suggest that hindbrain NPY neurons with projections to the hypothalamus participate in glucoprivic feeding and other glucoregulatory responses.
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)