Upregulation of cystathionine β-synthetase in the arcuate nucleus produces pain hypersensitivity via PKC upregulation and GluN2B phosphorylation in rats with chronic pancreatitis / 生理学报

Hydrogen sulfide (HS) contributes to visceral hyperalgesia in primary sensory neurons, but its role in central nervous system remains largely unknown. This study was to investigate the roles and underlying mechanisms of HS and its endogenous synthesis enzymes in the arcuate nucleus (ARC) in rat pancreatic hyperalgesia. Chronic pancreatitis (CP) was induced in male adult Sprague-Dawley rats by intra-pancreatic ductal injection of trinitrobenzene sulfonic acid (TNBS). Abdominal hyperalgesia was assessed by referred somatic behaviors to mechanical stimulation of rat abdomen. Western blot analysis was performed to detect protein expression in the ARC. CP markedly upregulated cystathionine β-synthetase (CBS) expression but did not alter cystathionine-γ-lyase level in the ARC at 4 weeks after TNBS injection. Although the expression of total GluN2B was not altered, CP greatly enhanced the phosphorylation level of GluN2B in the ARC when compared with age- and sex-matched control rats. CP also significantly increased expression of protein kinase Cγ (PKCγ) in the ARC. Arcuate microinjection of O-(Carboxymethyl) hydroxylamine hemihydrochloride (AOAA, an inhibitor of CBS) significantly attenuated abdominal pain in CP rats in a dose-dependent manner and reversed the CP-induced upregulation of p-GluN2B and PKCγ in the ARC. Furthermore, the GluN2B inhibitor or specific PKC inhibitor chelerythrine significantly attenuated abdominal hyperalgesia in CP rats. The p-GluN2B expression was also suppressed by PKC inhibitor. Taken together, our results suggest that the upregulation of CBS in the ARC leads to an activation of GluN2B via PKCγ, which may play an important role in generation of pain hypersensitivity of CP.

Purinergic P2X receptors and diabetic neuropathic pain / 生理学报

Diabetic peripheral neuropathy (DPN), one of the most common chronic complications of diabetes, is characterized by allodynia, hyperalgesia and spontaneous pain. Chinese epidemiological studies have shown that at least 25% diabetic patients suffered from painful DPN, which compromises patients' daily functioning and becomes a major health care problem. Although the pathogenesis of painful DPN is not fully understood and current treatment options are very limited, research in the field has advanced our understanding on the mechanism of painful DPN in the past Decade of Pain Research and Control. This review will mainly focus on evaluation of current diabetic animal models, possible molecular pathways and available therapies, with an emphasis on roles of purinergic receptor and its signaling transduction pathways. Common therapies address one or two DPN symptoms, while others offer wider symptom control, presumably by targeting pathophysiological mechanisms of DPN. Purinergic receptor signaling transduction pathways might become potential targets for treatment for painful DPN.

Nitric oxide promotes the differentiation of neural stem cells in vitro derived from the subventricular zone of neonatal rats / 中国应用生理学杂志

<p><b>OBJECTIVE</b>To observe the effect of nitric oxide (NO) on the differentiation of neural stem cells (NSCs) derived from subventricular zone (SVZ) of neonatal rats in vitro.</p><p><b>METHODS</b>Conventional method was used to isolate and culture the NSCs from SVZ. Diethylenetriamine/NO(DETA/NO) was used as NO donor and Nitro-L-arginine methylester (L-NAME) was used as inhibitor of nitric oxide synthase (NOS). The immunofluorescence was used to identify the expression of nestin (a marker of NSCs), beta-III-tubulin (Tuj-1, a marker of neurons), glial fibrillary acidic protein (GFAP, a marker of astrocytes) and nNOS. The concentration of NO in medium was measured by Greiss assay.</p><p><b>RESULTS</b>Cultured neurospheres were nestin-, BrdU- and nNOS-positive. After treatment with 40 micromol/L, 50 micromol/L and 60 micromol/L of DETA/NO for 5 days, the concentration of NO released was increased significantly (P < 0.01) as compared with that of the control group. The percentage of both differentiated neurons and astrocytes was increased significantly (P < 0.01 and P < 0.05) as compared with that of the control group. After treatment with 100 micromol/L, 150 micromol/L and 200 micromol/L of L-NAME for 5 days, the concentration of NO released was decreased as compared with that of the control group (P < 0.05). The percentage of both differentiated neurons and astrocytes were decreased as compared with that of the control group (P < 0.05).</p><p><b>CONCLUSION</b>NO could directly promote the differentiation of NSCs derived from rat subventricular zone in vitro.</p>

Possible involvement of integrin signaling pathway in the process of recovery from restraint stress in rats / 神经科学通报·英文版

<p><b>OBJECTIVE</b>To search novel genes or pathways involved in the recovery process after restraint stress in rats.</p><p><b>METHODS</b>We compared the hypothalamus transcriptional profiles of two different recovery patterns (fast recovery vs slow recovery) from restraint stress in rats using oligonucleotide microarray, the recovery pattern was determined by the decrement of plasma adrenocorticotropic-hormone (ACTH) and corticosterone levels during one hour recovery period after stress. A real-time quantitative RT-PCR was applied to validate the differential expressed genes.</p><p><b>RESULTS</b>Analysis of the microarray data showed that most of genes were not differentially expressed between fast recovery group and slow recovery group. Among the differentially expressed genes we found that talin, together with serine/threonine protein phosphatase PP1-beta catalytic subunit (PP-1B) and integrin alpha-6 precursor (VLA-6) genes, were at least 1.5 fold up-regulated in the fast recovery group, while junctional adhesion molecule 1 (F11r) was 1.5 fold down-regulated in the fast recovery group.</p><p><b>CONCLUSION</b>The results implied that integrin signaling pathway may be involved in the recovery from restraint stress in rats. The present study provided a global overview of hypothalamus transcriptional profiles during the process of recovery from the restraint stress in rats. The integrin signaling pathway seems to be involved in the recovery process, which deserves further study to clarify the integrin-mediated recovery mechanism after restraint stress.</p>

Effects of exercise on neurogenesis in the dentate gyrus and ability of learning and memory after hippocampus lesion in adult rats / 神经科学通报·英文版

Objective To explore the effects of exercise on dentate gyrus (DG) neurogenesis and the ability of learning and memory in hippocampus-lesioned adult rats. Methods Hippocampus lesion was produced by intrahippocampal microinjection of kainic acid (KA). Bromodeoxyuridine (BrdU) was used to label dividing cells. Y maze test was used to evaluate the ability of learning and memory. Exercise was conducted in the form of forced running in a motor-driven running wheel. The speed of wheel revolution was regulated at 3 kinds of intensity: lightly running, moderately running, or heavily running. Results Hippocampus lesion could increase the number of BrdU-labeled DG cells, moderately running after lesion could further enhance the number of BrdU-labeled cells and decrease the error number (EN) in Y maze test, while neither lightly running, nor heavily running had such effects. There was a negative correlation between the number of DG BrdU-labeled cells and the EN in the Y maze test after running. Conclusion Moderate exercise could enhance the DG neurogenesis and ameliorate the ability of learning and memory in hippocampus-lesioned rats.

Forced running enhances neurogenesis in the hippocampal dentate gyrus of adult rats and improves learning ability / 生理学报

To investigate the effect of forced running in motor-driven wheel on neurogenesis in the hippocampal dentate gyrus (DG) of adult rats, 5-bromo-2-deoxyuridine (BrdU), a thymidine analog was applied to mark cell proliferation. Neuroepthelial stem cell protein (nestin) expression was used to identify neural stem/precursor cells. The BrdU- and nestin-positive cells were examined by immunohistochemical technique. The ability of learning was evaluated by Y-maze test to explore the functional role of the newborn cells in the DG after forced running. It was found that the number of BrdU- and nestin-positive cells in the DG in running groups was significantly increased compared to that in the control group (P<0.05). The effect of forced running on neurogenesis was intensity-dependent. In addition, an improvement of learning ability in Y-maze test was observed after forced running. These findings suggest that forced running in motor-driven wheel could enhance neurogenesis in the hippocampal DG of adult rats and improve learning ability.

Drinking behavior and c-fos expression induced by chemical or electrical stimulation of SFO in rat brain / 中国应用生理学杂志

<p><b>AIM</b>To compare the drinking behavior and c-fos expression induced by chemical or electrical stimulation of subfornical organ (SFO) in rat brain.</p><p><b>METHODS</b>L-glutamic acid microinjection and constant electrical current were used as chemical and electrical stimulation of SFO, respectively. The water intake over 1 h was recorded and Fos expression was examined immunohistochemically.</p><p><b>RESULTS</b>A similar volume of water intake and Fos expression pattern were induced by both methods of stimulation of SFO. These include 11 forebrain areas (organum vasculosum of the lamina terminalis, median preoptic nucleus, hypothalamic paraventricular nucleus, supraoptic nucleus and lateral hypothalamic area, paraventricular nucleus, reunions nucleus and central medial nucleus of thalamus, bed nucleus of the stria terminalis, perifornical dorsal area and substantia innominata) and 4 areas of hindbrain (area postrema, nucleus solitary tract, lateral parabrachial nucleus and dorsal raphe nucleus).</p><p><b>CONCLUSION</b>The drinking behavior and Fos expression in brain induced by SFO stimulation are the results of activation of the neuronal bodies in SFO.</p>

Cold stress induces the suppression of splenic NK cell activity and the c-fos expression in rat brain / 中国应用生理学杂志

<p><b>AIM</b>To observe the effect of cold stress on the splenic NK cell activity and the c-fos expression in rat brain.</p><p><b>METHODS</b>Rats were maintained in cold chamber at 4 degrees for 4 h. The 51Cr release assay from YAC-1 cells was used to determine the splenic NK cell activity and the double staining of ABC method was employed to observe the immunoreactive expression of Fos, arginine-vasopressin and tyrosine hydroxylase.</p><p><b>RESULTS</b>Cold stress could induce a marked suppression of splenic NK cell activity and a significant expression of Fos protein in hypothalamic paraventricular nucleus(PVN), as well as in the brainstem locus coeruleus (LC). Double staining showed c-expression of Fos and arginine-vasopressin in some of PVN neurons, and co-expression of Fos and tyrosine hydroxylase in the majority of LC neurons.</p><p><b>CONCLUSION</b>The vasopressinergic neurons in PVN and the catecholaminergic neurons in LC might be probably involved in the suppression of splenic NK cell activity induced by cold stress.</p>