targeted-toxins

Anaclet C, Lin JS, Vetrivelan R, Krenzer M, Vong L, Fuller PM, Lu J (2012) Identification and characterization of a sleep-active cell group in the rostral medullary brainstem. J Neurosci 32(50):17970-17976. doi: 10.1523/JNEUROSCI.0620-12.2012

Summary: The authors attempt to locate and identify specific neuronal populations that promote sleep. One method utilized was 130-330 pg injections of orexin-SAP (Cat. #IT-20) into the parafacial zone. These results establish the parafacial zone as a delimited node of sleep-active neurons.

Related Products: Orexin-B-SAP (Cat. #IT-20)

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)

Cusulin C, Monni E, Ahlenius H, Wood J, Brune J, Lindvall O, Kokaia Z (2012) Embryonic stem cell-derived neural stem cells fuse with microglia and mature neurons. Stem Cells 30:2657-2671. doi: 10.1002/stem.1227

Summary: The fusogenic role of microglia could be even more important after NSC transplantation into brains affected by neurodegenerative diseases associated with microglia activation.

Usage: Primary Cells and NS Cell Coculture. Seven to twelve days after plating primary cells, NS cells were plated on top (10,000 cells per cm2)  for 1–3 days. Rat primary cells were treated with 10 nM Mac-1-SAP or Mouse IgG-SAP during the 5 days prior to the coculture, and analyzed 3 days thereafter.

Related Products: Mac-1-SAP rat (Cat. #IT-33), Mouse IgG-SAP (Cat. #IT-18)

Mittelman-Smith MA, Williams H, Krajewski-Hall SJ, McMullen NT, Rance NE (2012) Role for kisspeptin/neurokinin B/dynorphin (KNDy) neurons in cutaneous vasodilatation and the estrogen modulation of body temperature. Proc Natl Acad Sci U S A 109(48):19846-19851. doi: 10.1073/pnas.1211517109

Summary: Menopause is marked by estrogen withdrawal, and also by hot flushes. Given the fact that hypothalamic levels of kisspeptin/neurokinin B/dynorphin (KNDy) neurons are significantly altered in menopause, the authors investigated whether these neurons are involved in the generation of flushes. Rats received bilateral injections of NK3-SAP (Cat. #IT-63) into the arcuate nucleus – a total of 40 ng. Blank-SAP (Cat. #IT-21) was used as control. The data indicate that KNDy neurons promote cutaneous vasodilation, and play a role in 17β-estradiol modulation of body temperature, supporting the hypothesis that these neurons could play a role in the generation of hot flushes.

Related Products: NKB-SAP (Cat. #IT-63), Blank-SAP (Cat. #IT-21)

Kerbler GM, Hamlin AS, Pannek K, Kurniawan ND, Keller MD, Rose SE, Coulson EJ (2013) Diffusion-weighted magnetic resonance imaging detection of basal forebrain cholinergic degeneration in a mouse model. Neuroimage 66C:133-141. doi: 10.1016/j.neuroimage.2012.10.075

Summary: The authors examined the effectiveness of diffusion MRI using diffusion tensor imaging (DTI) and probabilistic tractography in detecting cholinergic loss in a mouse model. Mice received bilateral 0.2-μg icv injections of mu p75-SAP (Cat. #IT-16). Rabbit IgG-SAP (Cat. #IT-35) was used as control. The animals were then examined using DTI. The data indicate that DTI is a valid technique for assessment of cholinergic loss in septo-hippocampal tracts as a result of Alzheimer’s disease.

Related Products: mu p75-SAP (Cat. #IT-16), Rabbit IgG-SAP (Cat. #IT-35)

Vetrivelan R, Fuller PM, Yokota S, Lu J, Saper CB (2012) Metabolic effects of chronic sleep restriction in rats. Sleep 35(11):1511-1520. doi: 10.5665/sleep.2200

Summary: In order to investigate whether there is a correlation between sleep and weight the authors administered 200 nl of a 0.1% solution of orexin-SAP (Cat. #IT-20) to the ventrolateral preoptic area of rats. Although the lesioned animals slept less than the controls, weight gain was slower than controls.

Related Products: Orexin-B-SAP (Cat. #IT-20)

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)

Biggs LM, Simonton AR, Meredith M (2012) Intercalated nucleus modulates chemosensory processing in medial amygdala. Neuroscience 2012 Abstracts 781.07. Society for Neuroscience, New Orleans, LA.

Summary: The vomeronasal organ is necessary for interpretation by naive rodents (hamsters, mice) of many chemosensory signals. Information is relayed to medial amygdala (Me) via the accessory olfactory bulbs. FRA (Fos related antigen) responses in Me to chemosensory cues suggest this area is important for categorization of cues based on biological relevance to the animal. Anterior Me (MeA) is activated by all chemosensory cues (conspecific and heterospecific). Posterior Me (MeP) activates for conspecific and biologically relevant heterospecific stimuli only. Other heterospecific stimuli suppress MeP, apparently via GABA inhibition, while the adjacent medial-caudal intercalated nucleus (m-ICNc) is activated. Intercalated nuclei (ICNs) are groups of GABAergic cells between amygdala main-divisions. Those adjacent to basolateral and central amygdala (BLA, CeA) are known to mediate BLA, CeA responses via GABA inhibition, modulated by inhibitory DA-D1 receptors on ICN cells. We hypothesize that m-ICNc modulates MeP in a similar manner, as suggested by FRAs data, but this has not yet been tested directly. In hamsters, we show a hyperpolarization of MeP cells and suppression of ongoing spiking in whole-cell slice electrophysiology using in-slice stimulation of m-ICNc. The effect of dopamine and other modulators on this functional relationship is under study with agonists and antagonists. ICN, but not Me, cells carry mu-opioid receptors (MORs). In mice, we use Dermorphin-Saporin, a toxin that selectively destroys MOR+ neurons, to lesion m-ICNc to assess its role in chemosensory responses in MeP. Also in mice, a specific MUP protein in male urine (mMU) facilitates learning of a male’s chemosensory signature by females. We have quantified Me response to high and low molecular weight (HMW, LMW) fractions (LMW lacks protein) and whole mMU using FRAs immediate early gene expression. Preliminary results show no significant difference between HMW, LMW, or whole mMU in Me, however within the BLA (involved in volatile odor learning), there are significant differences in activity between stimuli in females without post-weaning exposure to male urine and no prior exposure to adult male urine.

Related Products: Dermorphin-SAP / MOR-SAP (Cat. #IT-12)

Carr F, Géranton SM, Hunt SP (2012) Descending facilitation contributes to changes in dorsal horn gene expression in a rat model of inflammatory joint pain. Neuroscience 2012 Abstracts 785.07. Society for Neuroscience, New Orleans, LA.

Summary: Chronic pain is associated with increased excitability and changes in gene expression within the dorsal horn. Descending facilitation from the rostral ventromedial medulla (RVM) is known to contribute to this excitability and behavioural hypersensitivity in a number of pain states. This would suggest that some of the gene changes associated with chronic pain could be driven by descending pathways terminating in the dorsal horn. We have previously demonstrated that ablation of a subset of RVM neurons expressing the mu opioid receptor (MOR) attenuates behavioural hypersensitivity following joint inflammation. The aim of the present study was to combine lesion of the RVM with microarray analysis of the dorsal horn to identify genes regulated by descending facilitation in this pain model. Selective lesion of MOR expressing cells of the RVM was carried out in rats by microinjection of the selective toxin dermorphin-saporin. Non-lesioned controls received vehicle microinjection. 4 weeks after the lesion procedure when depletion of the MOR+ cells was complete, both groups received an injection of 10μl Complete Freund’s Adjuvant to the left ankle joint. 7 days later the animals were sacrificed and the ipsilateral quadrant of the dorsal horn of the spinal cord lumbar region (L4-L6) removed. RNA was extracted and microarray analysis carried out using Affymetrix GeneChip Rat Gene 1.0 ST Arrays. Raw data was analysed in R using Bioconductor open source software. Limma testing was applied and a list of genes differentially regulated in animals with prior RVM lesion compared to non-lesioned controls was generated. The majority of differentially regulated genes (73%) were downregulated in the lesioned group. We used the DAVID bioinformatics resource to cluster the genes into groups with similar functional annotations (Huang et al., 2009). This analysis identified 16 gene clusters with significantly enriched functional annotations. Among these enriched functions were ribosomal function and biogenesis, inflammatory response (including the chemokine CXCL10), GPCR signalling (including the serotonin receptor 5HTR1D) and transcriptional regulation (including the transcriptional repressor RCOR2). Following on from identification of functional categories, validation of genes of interest was carried out using RT-qPCR. Our findings suggest that descending facilitation contributes to gene expression changes within the dorsal horn and that this may correlate with behavioural hypersensitivity observed in chronic pain.

Related Products: Dermorphin-SAP / MOR-SAP (Cat. #IT-12)

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)