Neurogenesis inhibition in the dorsal vagal complex by chronic immobilization stress in the adult rat

The dorsal vagal complex (DVC) is the brainstem integrative center that mediates the satiety reflex and relays autonomic neural responses to stress. The DVC displays adult neurogenesis, intrinsic neural stem cells and a high brain-derived neurotrophic factor (BDNF) content, effectors of plasticity that are modulated by stress in the hippocampus. In this study we asked whether neurogenesis and BDNF expression in the DVC are altered by stress, in parallel with food intake reduction. To this end, neurogenesis was assessed in adult rats in vivo by repetitive 5-bromo-2′-deoxyuridine (BrdU) administration without (controls) or with daily sessions of immobilization stress (1 h/day), and were allowed to survive for 2 weeks after the end of BrdU treatment. Neurogenic proliferation in the brainstem was detected by immunohistochemistry and confocal microscopy mainly in the area postrema and the nucleus tractus solitarius; newly formed neurons amounted to about 35% of all BrdU-labeled cells in the DVC of control rats. Chronic immobilization stress induced a significant decrease in neurogenic proliferation in the DVC which reached 50% in the area postrema. The number of newly-formed neurons was also decreased by chronic immobilization stress in the DVC, and this effect was again maximal in the area postrema; the proportion of BrdU-labeled cells that were neurons was unchanged. In vitro neurosphere assay was then performed on microdissected DVC tissue from another cohort of chronically stressed and control rats. Chronic immobilization stress induced a significant decrease of the total neurosphere number per rat DVC in both primary and secondary cultures, indicating that intrinsic neural stem cell frequency was decreased by chronic stress in DVC tissue. Tissue BDNF concentration in the DVC, as assessed by enzyme-linked immunosorbent assay, was not significantly altered when compared with controls after 3, 6, 9 or 13 days of chronic immobilization stress. These results further characterize neurogenesis in the DVC and suggest its involvement in the long-term regulation of food intake.     

Atropine methyl nitrate increases myenteric but not dorsal vagal complex Fos-like immunoreactivity in the rat

Atropine methyl nitrate (AMN, 0.05, 0.5 and 25 mg/kg) intraperitoneally increased Fos-like immunoreactivity (Fos-LI) in the myenteric plexus, but not the dorsal vagal complex (DVC, the area postrema (AP), nucleus of the solitary tract (NTS) and the dorsal motor nucleus of the vagus (DMV)) in adult, male Sprague-Dawley rats. A 3 mg/kg AMN dose decreased intake of 15% sucrose, but failed to increase Fos-LI in both locations. In conclusion, the myenteric plexus may play a local role in the behavioral response evoked by AMN.     

Vestibular nucleus projections to nucleus tractus solitarius and the dorsal motor nucleus of the vagus nerve: potential substrates for vestibulo-autonomic interactions

Autonomic effects of vestibular stimulation are important components of phenomena as diverse as acute vestibular dysfunction and motion sickness. How ever, the organization of neural circuits mediating these responses is poorly understood. This study presents evidence for direct vestibular nucleus projections to brain stem regions that mediate autonomic function. One group of albino rabbits received injections of Phaseolus vulgaris leucoagglutinin into the vestibular nuclei. The tracer was visualized immunocytochemically with standard techniques. Anterogradely labeled axons from the caudal medial vestibular nucleus (cMVN) and inferior vestibular nucleus (IVN) could be traced bilaterally to nucleus tractus solitarius (NTS). Fewer axons ended near the somata of neurons in the dorsal motor nucleus of the vagus nerve (DMX). A second group of rabbits received pressure or iontophoretic injections of cholera toxin B-HRP or Fluoro-Gold into a region including NTS and DMX. Retrogradely labeled neurons were observed bilaterally in the caudal half of cMVN and ipsilaterally in IVN. The labeled somata were small and they tended to occupy the center of cMVN in transverse sections. These previously unreported vestibular nucleus projections to NTS and DMX are a potential substrate for vestibular influences on autonomic function. In particular, they may contribute to both cardiovascular control during head movements (e.g., orthostatic reflexes) and autonomic manifestions of vestibular dysfunction, motion sickness and exposure to altered gravitational environments.     

Presenilin-1 is expressed in neural progenitor cells in the hippocampus of adult mice.

The functions of the presenilin-1 (PS-1) protein remain largely unknown. In adult brain PS-1 is expressed principally in neurons. However during development PS-1 is expressed more widely including in embryonic neural progenitors. To determine if PS-1 is expressed in neural progenitors in adult hippocampus we used bromodeoxyuridine (BrdU) labeling combined with immunostaining for BrdU, PS-1 and markers of neuronal or glial differentiation. Most BrdU labeled cells also expressed PS-1 at a time when few BrdU labeled cells expressed the early neuronal markers beta-III tubulin or TOAD-64 and none expressed mature neuronal (NeuN or calbindin) or astrocytic (GFAP) markers. Cells expressing PS-1 and the neural progenitor marker nestin were also found. Thus PS-1 is expressed in neural progenitor cells in adult hippocampus implying its possible role in neurogenesis in adult brain.     

Differential neurogenesis and gliogenesis by local and migrating neural stem cells in the olfactory bulb

The rostral migratory stream (RMS) is a unique forebrain structure that provides a long-distance migratory route for the neural stem cells of the periventricular region towards the olfactory bulb (OB). The purpose of the study presented here is to examine the extent of neurogenesis and gliogenesis by the neural stem cells of different origins (periventricular vs. intrabulbar) in the OB. After the RMS had been subjected to injury, the rats received intraperitoneal injections of 5-bromodeoxyuridine (BrdU) and were further reared for 2 weeks. Neuronal and glial differentiations of the BrdU(+) cells in the olfactory bulbar granule cell (OB-GCL) and the olfactory glomerular (OB-GL) layers were examined immunohistochemically using antibodies against neuronal (NeuN, neuronal nuclei) and glial (GFAP, glial fibrillary acidic protein) markers in the OBs with injured and uninjured (control) RMS. In the completely RMS-lesioned OB, where migration of the periventricular neural stem cells was inhibited, a small number of BrdU(+) NeuN(+) cells were found in both the OB-GCL and OB-GL. The BrdU(+) NeuN(+) cells accounted for a much higher percentage of the BrdU(+) cells on the control side (OB-GCL, 36.7%; OB-GL, 8.8%) than on the completely RMS-lesioned side (OB-GCL, 3.7%; OB-GL, 0.6%). The percentage of the BrdU(+) GFAP(+) cells relative to the BrdU(+) cells did not show any major difference between the control and completely RMS-lesioned sides. This study revealed differences in neurogenesis and gliogenesis between the local and migrating neural stem cells in the OB of the adult rodent.     

模拟失重后大鼠海马齿状回神经发生的实验研究

观察模拟失重对大鼠海马齿状回神经发生的影响,为进一步阐明模拟失重对成年大鼠海马齿状回神经发生影响的规律及其相关生物学机制提供基本的实验依据。采用尾部悬吊法建立大鼠模拟失重模型,通过5-溴-2’-脱氧尿苷(5-bromo-2’-de-oxyuridine,BrdU)标记分裂细胞、微管相关蛋白(doublecortin,DCX)标记神经干细胞、神经元核蛋白(NeuN)标记神经元及胶质原纤维酸性蛋白(GFAP)标记神经胶质细胞的单、双重免疫组织化学染色方法比较尾部悬吊后7、14、28d模拟失重组大鼠与相应时间对照组大鼠之间海马齿状回神经前体细胞增殖、迁移和分化的情况。结果显示:模拟失重后7、14d尾部悬吊法模拟失重大鼠齿状回的BrdU免疫阳性细胞数目较相应对照组明显减少(P<0.01),而模拟失重后28d时两组大鼠齿状回BrdU免疫阳性细胞数目无显著差异(P>0.05)。本研究结果提示,模拟失重可抑制海马齿状回神经发生的水平。     

Distribution of c-Fos immunoreactive neurons in the brain after intraperitoneal injection of apelin-12 in Wistar rats

The present study surveyed activation of central neurons following peripheral administration of apelin-12 (AP12), an apelin peptide homologue, by examining the distribution of neurons expressing c-Fos protein. AP12 is known to induce gastric acid secretion among other physiological functions such as regulation of circulation. It was recently reported that apelin counteracted the effect of arginine vasopressin (AVP) in the maintenance of body fluid homeostasis. We attempted to clarify which neurons in the central nervous system express c-Fos protein after intraperitoneal injection of AP12. Intraperitoneally administered AP12 induced expression of c-Fos protein in several nuclei throughout the brain. In the paraventricular nucleus of the hypothalamus (PAH), lateral hypothalamic area (LH), paraventricular nucleus of the thalamus (PVT), periaqueductal gray matter (PAG), bed nucleus of the stria terminalis (BNST), locus coeruleus (LC), lateral parabrachial nucleus (Pbl), the complex of the solitary tract nucleus (NTS) and dorsal motor nucleus of the vagus nerve (DMX), numbers of neurons expressing c-Fos protein were much higher in test than in control experiments. These findings suggest that AP12 stimulates central neurons that may play roles in the regulation of gastric acid, and hypothalamic neurons that may play roles in the maintenance of body fluid homeostasis as well as other physiological functions.     

成年肌萎缩脊髓侧索硬化症转基因鼠脊髓增殖细胞的分化

目的 探讨成年肌萎缩脊髓侧索硬化症(ALS)转基因模型鼠脊髓内增殖细胞的类型及分化情况. 方法 对ALS转基因鼠发病期进行BrdU标记,分别于不同时间点取材,冷冻切片,应用免疫荧光双标及三标染色技术检测ALS转基因鼠病变进展过程中脊髓内增殖细胞的分化情况. 结果 成年ALS转基因鼠发病期脊髓的中央管、灰质、白质均未检测到BrdU/DCX双标记阳性细胞和BrdU/NeuN双标记阳性细胞.灰质、白质和中央管周围检测到大量NG2阳性细胞,阳性细胞数量随病变进展逐渐减少,NG2阳性细胞多呈BrdU阳性表达;可检测到少量BrdU/A2B5双标记阳性细胞;ALS转基因鼠发病期脊髓BrdU/GFAP双标记阳性细胞较多,部分双阳性细胞呈Nestin阳性,而野生型鼠脊髓内未检测到BrdU/GFAP双标记阳性细胞.结论 神经退行性病变激活ALS转基因鼠脊髓内源性增殖细胞向神经胶质细胞方向分化,未检测到向神经元方向分化,内源性增殖细胞尚不能有效地促进退行性病变的修复.     

A possible role for dopamine D3 receptor stimulation in the induction of neurogenesis in the adult rat substantia nigra

Small molecule neurotransmitters, such as dopamine, have been shown to regulate cell cycles in the developing brain [Spencer GE, Klumperman J, Syed NI (1998) Neurotransmitters and neurodevelopment: Role of dopamine in neurite outgrowth, target selection and specific synapse formation. Perspect Dev Neurobiol 5:451-467; Ohtani N, Goto T, Waeber C, Bhide PG (2003) Dopamine modulates cell cycle in the lateral ganglionic eminence. J Neurosci 23:2840-2850] and may provide an alternative to traditional growth factors for the regulation of neurogenesis. Specifically, the dopamine D3 receptor appears to play an important role in neural development, and shows a persistent expression through adulthood in the proliferative subventricular zone [Diaz J, Ridray S, Mignon V, Griffon N, Schwartz JC, Sokoloff P (1997) Selective expression of dopamine D3 receptor mRNA in proliferative zones during embryonic development of the rat brain. J Neurosci 17:4282-4292]. Furthermore, pharmacological stimulation of D3 receptors promotes proliferation of adult subventricular zone cells, both in vitro [Coronas V, Bantubungi K, Fombonne J, Krantic S, Schiffmann SN, Roger M (2004) Dopamine D3 receptor stimulation promotes the proliferation of cells derived from the post-natal subventricular zone. J Neurochem 91:1292-1301] and in vivo [Van Kampen JM, Hagg T, Robertson HA (2004) Induction of neurogenesis in the adult rat subventricular zone and neostriatum following dopamine D3 receptor stimulation. Eur J Neurosci 19:2377-2387]. In earlier work, we have demonstrated the induction of cell proliferation in the subventricular zone of the adult rat brain accompanied by a dramatic 10-fold induction of neurogenesis in the neighboring neostriatum, following administration of the preferential D3 receptor agonist, 7-hydroxy-N,N-di-n-propyl-2-aminotetralin [Van Kampen JM, Hagg T, Robertson HA (2004) Induction of neurogenesis in the adult rat subventricular zone and neostriatum following dopamine D3 receptor stimulation. Eur J Neurosci 19:2377-2387]. Dopamine D3 receptors have also been found in the substantia nigra [Diaz J, Pilon C, Le Foll B, Gross C, Triller A, Schwartz JC, Sokoloff P (2000) Dopamine D3 receptors expressed by all mesencephalic dopamine neurons. J Neurosci 20:8677-8684], a region of the adult brain shown to exhibit ongoing cytogenesis and neurogenic potential [Lie DC, Dziewczapolski G, Willhoite AR, Kaspar BK, Shults CW, Gage FH (2002) The adult substantia nigra contains progenitor cells with neurogenic potential. J Neurosci 22:6639-6649; Zhao M, Momma S, Delfani K, Carlen M, Cassidy RM, Johansson CB, Brismar H, Shupliakov O, Frisen J, Janson AM (2003) Evidence for neurogenesis in the adult mammalian substantia nigra. Proc Natl Acad Sci U S A 100:7925-7930]. We have found that chronic intraventricular administration of 7-hydroxy-N,N-di-n-propyl-2-aminotetralin triggers a profound induction of cell proliferation in the rat substantia nigra and promotes the adoption of a neuronal phenotype in a proportion of these newly generated cells.     

Hippocampal CA field neurogenesis after pilocarpine insult: The hippocampal fissure as a neurogenic niche

Pilocarpine model for temporal lobe epilepsy has shown aberrant neurogenesis, but mainly restricted to the dentate gyrus (DG). Herein, by using a modified protocol, combining pilocarpine with ipratropium bromide, we unexpectedly observed a heretofore-unrecognized distinct cellular population expressing the neuroprogenitor marker doublecortin (DCX) on post insult days (PID) 10, 14 and 18, mainly located in the temporal segment of the hippocampal fissure (hf). Some of these DCX+ cells possessed high morphological complexity and seemed to disperse toward the CA fields. Next, we injected bromodeoxyuridine (BrdU) in early (PID 2–4) and delayed (PID 5–7) fashions and killed the rats 7–35 days later for immunohistochemical and anatomical analysis. Massive increase of BrdU labeling was found in the delayed group and the neural stem cell-specific marker nestin was highly expressed in the same narrow band on PID7, so was glial fibrillary acidic protein (GFAP). Using double labeling with BrdU and a mature neuron marker NeuN, we found discrete but clear BrdU+/NeuN+ double labeled cells in the Cornu Ammonis (CA) pyramidal cell layer on PID35. Based on immunohistochemical and anatomical observations, as well as time-course analysis of BrdU, nestin, GFAP, DCX and NeuN expressions in this population of cells located in/near hf, we wish to suggest that this structure harbors neurogenic niches, in addition of the possible dispersion of neuroprogenitors from subgranular niches to CA fields also revealed by this study. Our results support the few previous reports demonstrating hippocampal CA field neurogenesis in adult rats. Mechanistic basis of the phenomenon is discussed.     

Hippocampal adult neurogenesis is enhanced by chronic eszopiclone treatment in rats

The adult hippocampal dentate gyrus (DG) exhibits cell proliferation and neurogenesis throughout life. We examined the effects of daily administration of eszopiclone (Esz), a commonly used hypnotic drug and γ‐aminobutyric acid (GABA) agonist, compared with vehicle, on DG cell proliferation and neurogenesis, and on sleep–wake patterns. Esz was administered during the usual sleep period of rats, to mimic typical use in humans. Esz treatment for 7 days did not affect the rate of cell proliferation, as measured by 5‐bromo‐2′‐deoxyuridine (BrdU) immunostaining. However, twice‐daily Esz administration for 2 weeks increased survival of newborn cells by 46%. Most surviving cells exhibited a neuronal phenotype, identified as BrdU–neuronal nuclei (NeuN) double‐labeling. NeuN is a marker of neurons. Non‐rapid eye movement sleep was increased on day 1, but not on days 7 or 14 of Esz administration. Delta electroencephalogram activity was increased on days 1 and 7 of treatment, but not on day 14. There is evidence that enhancement of DG neurogenesis is a critical component of the effects of antidepressant treatments of major depressive disorder (MDD). Adult‐born DG cells are responsive to GABAergic stimulation, which promotes cell maturation. The present study suggests that Esz, presumably acting as a GABA agonist, has pro‐neurogenic effects in the adult DG. This result is consistent with evidence that Esz enhances the antidepressant treatment response of patients with MDD with insomnia.     

Increased BrdU incorporation reflecting DNA repair, neuronal de-differentiation or possible neurogenesis in the adult cochlear nucleus following bilateral cochlear lesions in the rat

Neurogenesis is known to occur in response to injury in the brain, for example, as a result of neurodegenerative diseases. However, there have been few investigations into how the brain responds to damage to peripheral sensory nerves, in other areas such as the brainstem. Here, we report that bilateral surgical lesions of the cochlea result in increased incorporation of the DNA replication marker, bromodeoxyuridine (BrdU), in cells of the brainstem cochlear nucleus (CN) of the adult rat, suggesting either cell proliferation or DNA repair. Some of the BrdU-labelled cells colabelled for the mature neuron marker, NeuN and the GABAergic enzyme GAD-65, suggesting the possibility that neurogenesis might have occurred and resulted in the generation of new neurons with a GABAergic phenotype. However, some of the mature neurons also re-expressed immature neuronal intermediate filament and microtuble-associated proteins, without apoptotic neuronal death, which suggests that the colabelling of BrdU with NeuN and GAD-65 may not be a true reflection of neurogenesis, but injury-stimulated neuronal dedifferentiation. These results suggest the possibility that DNA repair, neuronal de-differentiation or possible neurogenesis occurs in the cochlear nucleus, in response to damage to the peripheral auditory system.     

神经元核抗原在大鼠中枢神经系统神经元的不同表达

目的观察正常大鼠中枢神经系统(CNS)内神经元核抗原(NeuN)的表达。方法正常成年SD大鼠5只,常规固定,恒冷箱切片,免疫组织化学、免疫荧光染色、尼氏染色。结果NeuN在成年大鼠CNS神经元有4种表达:大部分神经元(大脑皮质、基底核、脊髓背角等)有明显表达;部分神经元为中等表达(三叉神经脊束核、下丘脑室旁核等);部分神经元为弱表达(孤束核、蓝斑等);而有些核团神经元缺乏NeuN的表达(视上核、弓状核、迷走神经背核等)。结论中枢神经系统不同区域或核团的神经元NeuN的表达程度不同,有的区域或核团神经元缺乏NeuN表达。     

Perineuronal germinal cells in the rat cerebral cortex

The generation and renewal of cells in the adult mammalian central nervous system maintains brain functions, including plasticity. Even in the cerebral cortex of adult mammals, glial cells are thought to be replaced with newly generated cells every 100 days. Recently, we demonstrated that this proliferation is stimulated by neural activity. However, whether any germinal areas exist in the cortical parenchyma is unknown. Here, we examined the proliferating cell dynamics in the cerebral cortex of adult rats using BrdU labeling and immunohistochemistry for NeuN and lamin B1. At 2 h after a single injection of BrdU, more than 80% of BrdU-labeled cells were observed in the perineuronal territory in which the BrdU-labeled nuclei were located within 5 μm from neuronal nuclei. The ratio of perineuronal cells to nonperineuronal cells in BrdU-labeled cells gradually decreased over the 2 weeks following BrdU injection. These observations indicate that numerous cortical cells proliferate in the perineuronal territory, the germinal soil, and that part of these newly generated cells migrate from the perineuronal territory into the surrounding areas during the 2 weeks following mitosis.     

Non-angiotensin II [(125)I] CGP42112 binding is a sensitive marker of neuronal injury in brainstem following unilateral nodose ganglionectomy: comparison with markers for activated microglia

Previously we reported that a non-angiotensin II [(125)I] CGP42112 binding site is up-regulated in rat brainstem nuclei as a result of unilateral nodose ganglionectomy. In the present study, we compared non-angiotensin II [(125)I] CGP42112 binding with microglia/macrophage activation following nodose ganglionectomy, using both in vitro autoradiography and immunohistochemistry. Specific [(125)I] CGP42112 binding was observed in the nucleus of the solitary tract (NTS) and revealed an AT(2) receptor component as well as a non-angiotensin II receptor component. Subsequent to unilateral nodose ganglionectomy, [(125)I] CGP42112 binding in the ipsilateral NTS was increased approximately two-fold and was also induced in the ipsilateral dorsal motor nucleus (DMX) and the nucleus ambiguus (n.amb). This non-angiotensin II [(125)I] CGP42112 binding site was displaced by CGP42112 but not other ligands. Increased [(3)H] PK11195 binding (a known marker of reactive gliosis) was also observed in the same brainstem nuclei as non-angiotensin II [(125)I] CGP42112 binding after nodose ganglionectomy. The similarity in binding patterns between [(125)I] CGP42112 and [(3)H] PK11195 was shown to be primarily due to retrograde degeneration in the ipsilateral NTS, DMX and n.amb, as both radioligands were localized to similar cellular targets within the interstial space and over cellular debris. Immunohistochemical data confirmed reactive gliosis within the ipsilateral NTS, DMX and n.amb, following nodose ganglionectomy, which was predominantly characterized by an increase in OX-42 immunoreactivity (a marker for activated microglia/macrophages), with only a small increase in glial fibrillary acidic protein immunoreactivity (a marker of astrogliosis) detected. These data demonstrate for the first time that non-angiotensin II [(125)I] CGP42112 binding is associated with activated microglia, as well as macrophages, following unilateral nodose ganglionectomy. Furthermore, these studies also demonstrate the potential use of non-angiotensin II [(125)I] CGP42112 binding as a marker for quantitating inflammatory events which occur as a result of damage to the CNS.     

Differential effect of orexins (hypocretins) on serotonin release in the dorsal and median raphe nuclei of freely behaving rats

Orexin (hypocretin)-containing neurons in the perifornical hypothalamus project to widespread regions of the brain, including the dorsal and median raphe nuclei [Peyron C, Tighe DK, van den Pol AN, de Lecea L, Heller HC, Sutcliffe JG, Kilduff TS (1998) Neurons containing hypocretin (orexin) project to multiple neuronal systems. J Neurosci 18:9996-10015; Wang QP, Koyama Y, Guan JL, Takahashi K, Kayama Y, Shioda S (2005) The orexinergic synaptic innervation of serotonin- and orexin 1-receptor-containing neurons in the dorsal raphe nucleus. Regul Pept 126:35-42]. Orexin-A or orexin-B was infused by reverse microdialysis into the dorsal raphe nucleus or median raphe nucleus of freely behaving rats, and extracellular serotonin was simultaneously collected by microdialysis and analyzed by high-performance liquid chromatography. We have found that orexin-A produced a dose-dependent increase of serotonin in the dorsal raphe nucleus, but not in the median raphe nucleus. However, orexin-B elicited a small but significant effect in both the dorsal raphe nucleus and median raphe nucleus. Orexins may have regionally selective effects on serotonin release in the CNS, implying a unique interaction between orexins and serotonin in the regulation of activities including sleep-wakefulness.     

Ischemia induces cell proliferation and neurogenesis in the gerbil hippocampus in response to neuronal death

We studied hippocampal cellular proliferation and neurogenesis processes in a model of transient global cerebral ischemia in gerbils by labelling dividing cells with 5'-Bromo-2'-deoxyuridine (BrdU). Surrounding the region of selective neuronal death (CA1 pyramidal layer of the hippocampus), an important increase in reactive astrocytes and BrdU-labelled cells was detected 5 days after ischemia. A similar result was found in the dentate gyrus (DG) 12 days after ischemia. The differentiation of the BrdU+ cells was investigated 28 days after BrdU administration by analyzing the morphology, anatomic localization and cell phenotype by triple fluorescent labelling (BrdU, adult neural marker NeuN and DNA marker TOPRO-3) using confocal laser-scanning microscopy. This analysis showed increased neurogenesis in the DG in case of ischemia and triple positive labelling in some newborn cells in CA1. Seven brain hemispheres from gerbils subjected to ischemia did not develop CA1 neuronal death; hippocampus from these hemispheres did not show any of the above mentioned findings. Our results indicate that ischemia triggers proliferation in CA1 and neurogenesis in the DG in response to CA1 pyramidal neuronal death, independently of the reduced cerebral blood flow or the cell migration from subventricular zone (SVZ).     

大鼠精神分裂症后自发性运动量及海马神经发生的改变

目的:探讨成年大鼠精神分裂症后自发性运动量和海马神经发生的改变。方法:通过连续2周腹腔注射环苯已哌啶(phencyclidine,PCP)建立大鼠精神分裂症模型,利用动物运动分析系统监测大鼠自发性运动量,5-溴-2-脱氧尿苷嘧啶(BrdU)标记新生的神经细胞,用免疫荧光标记法监测海马齿状回BrdU、NeuN、S-100β的表达,利用激光共聚焦显微镜观察海马神经细胞的增殖与分化情况。结果:精神分裂症模型大鼠比对照组大鼠自发性运动量高出2～3倍(P0.05);BrdU阳性细胞数约下降了24%(P0.05);两组BrdU阳性细胞的分化无明显差异性(P0.05),大多分化为神经元。结论:精神分裂症可导致成年大鼠自发性运动量增加,并引起海马神经发生的改变,降低神经细胞的增殖。     

The role of catecholaminergic neurons in the hypothalamus and medullary visceral zone in response to restraint water-immersion stress in rats

The activity of catecholaminergic neurons in the hypothalamus and the medullary visceral zone (MVZ) in rats in response to restraint water-immersion stress (RWIS) was measured by use of dual Fos and tyrosine hydroxylase (TH) immunohistochemistry. In RWIS rats Fos immunoreactive (Fos-IR) nuclei dramatically increased in the paraventricular nucleus (PVN), the supraoptic nucleus (SON), the dorsal motor nucleus of the vagus (DMV), the nucleus of the solitary tract (NTS), the area postrema (AP), and the ventrolateral medulla (VLM). A small number of TH-immunoreactive (TH-IR) and Fos/TH double-labeling neurons in the PVN, and their absence from the SON, were observed in both RWIS and nonstressed rats. More TH-IR neurons were observed in the MVZ of RWIS rats than in nonstressed rats. In RWIS and nonstressed rats, the percentage of Fos-IR nuclei in TH-IR neurons was 38.0 and 14.3% in the DMV, 34.4 and 9.7% in the NTS, 18.6 and 4.5% in the AP, and 45.7 and 18.9% in the VLM, respectively. In conclusion, catecholaminergic neurons in the MVZ are involved in the response to RWIS; although the PVN and SON also participate in the response to RWIS, the mechanism is not via catecholaminergic neurons.     

大鼠脊髓发育过程中神经干细胞的分化

目的:研究正常大鼠脊髓发育过程中神经干细胞的分化规律。方法:应用免疫荧光染色技术,检测Nestin、NeuN、MAP2、GFAP、CNPase阳性细胞在大鼠胚胎期及生后脊髓内的分布及变化情况。结果:胚胎发育早期,脊髓中央管、灰质、白质均可检测到Nestin阳性细胞,生后Nestin阳性细胞数量逐渐减少。大鼠脊髓神经元的发生呈现明显的背腹模式,孕14d(E14)脊髓内可检测到NeuN阳性细胞,E16 NeuN阳性细胞逐渐增多,腹侧NeuN阳性细胞核体积较大,分布较稀疏,背侧神经元细胞核体积较小,分布较密集。MAP2染色结果与NeuN一致。胶质细胞的分化、成熟在生后初期进行,P4可检测到GFAP及CNPase阳性细胞,主要分布于脊髓白质内,P30在脊髓灰质内可检测到GFAP阳性细胞,细胞分支较多且短。结论:正常大鼠脊髓发育中神经干细胞的分化呈现一定规律性,向神经元方向化较早且呈明显的背腹模式,胶质细胞的分化较晚。