N-甲基-D-天冬氨酸受体与中枢神经系统缺血性疾病的关系

N-甲基-D-天冬氨酸受体(N-methyl-D-aspartate)是兴奋性氨基酸谷氨酸(Glu)的特异性受体,属配体电压双重门控的离子通道,由3种不同的亚基组成的功能复合体,目前已发现N-甲基-D-天冬氨酸受体(NMDAR)至少存在7个亚单位,参与学习、记忆形成及神经系统的发育等生理功能,病理情况下,NMDAR还与中枢神经系统缺血性神经毒性损害密切相关,本篇将对NMDAR的结构、功能及其参与中枢神经系统神经毒性损害的机制作一综述。     

视神经脊髓炎合并抗N-甲基-D-天冬氨酸受体脑炎1例

目的 探讨视神经脊髓炎合并抗N-甲基-D-天冬氨酸(NMDA)受体脑炎的临床特征。方法 报道本院收治的1例视神经脊髓炎合并抗N-甲基-D-天冬氨酸受体脑炎的临床特点及诊治经过,并结合文献分析该病的特征。结果 患者为21岁女性,表现为腹泻后急性起病的下肢麻木无力、昏睡、视物模糊; MRI示双侧基底节、海马、桥臂、齿状回、延髓背侧多发异常信号,同时伴有颈髓多发条片状长T₂异常信号。脑脊液NMDA受体抗体阳性,血清和脑脊液水通道蛋白4(AQP4)抗体阳性,合并心动过缓并发症,筛查未发现肿瘤; 经激素冲击、丙种球蛋白及免疫抑制剂治疗后症状逐渐好转至痊愈。结论 视神经脊髓炎合并抗N-甲基-D-天冬氨酸受体脑炎可以在感染后起病,症状和影像学主要表现为两种疾病的叠加,可出现心动过缓并发症,早期积极行免疫治疗效果较好。     

致死剂量N-甲基-D-天冬氨酸中毒模型小鼠对丙泊酚的反应*☆

背景：丙泊酚具有较好的抗惊厥作用,但其作用机制尚不清楚。 目的:观察丙泊酚对致死剂量N-甲基-D-天冬氨酸中毒模型小鼠的行为学及存活率的影响。 方法：建立N-甲基-D-天冬氨酸致死模型昆明小鼠,给药前10 min,腹腔注射丙泊酚12.5,25,50,75,100 mg/kg,观察中毒小鼠的行为学改变及存活率,阳性对照组在造模前腹腔注射非特异性的N-甲基-D-天冬氨酸受体拮抗剂地佐环平 2 mg/kg,为排除丙泊酚溶剂脂肪乳可能的作用,设定了脂肪乳组,在造模前腹腔注射等容积的脂肪乳作为对照。 结果与结论：腹腔注射N-甲基-D-天冬氨酸175 mg/kg可导致小鼠全身惊厥发生并且很快死亡,而提前给予丙泊酚12.5,25,50,75,100 mg/kg后,可见其可剂量依赖性的对抗小鼠惊厥的发生,并降低小鼠的死亡率,地佐环平(2 mg/kg)可完全预防惊厥发生,而脂肪乳不能抑制惊厥的发生,对致死剂量N-甲基-D-天冬氨酸中毒模型小鼠无保护作用。提示丙泊酚的抗惊厥作用可能与N-甲基-D-天冬氨酸受体有关。     

抗N-甲基-D-天冬氨酸受体脑炎2例报道并文献复习

目的探讨抗N-甲基-D-天冬氨酸受体脑炎患者的临床特点及诊治。方法收集2例我院诊治的抗N-甲基-D-天冬氨酸受体脑炎患者的临床资料,并通过计算机检索中国知网、万方数据库,收集2010年至2013年在我国各种期刊上公开发表的关于抗N-甲基-D-天冬氨酸受体脑炎患者的文献。结果本文报道的2例及9篇文献检索的23例患者主要表现为发热、精神行为异常、智能减退、抽搐、不自主运动及表现为睡眠减少、心率快、汗液分泌异常等自主神经功能障碍。本文报道的2例患者男女各1例,年龄分别为15.5岁、14岁,均未发现畸胎瘤;文献检索的23例患者女性14例、男性9例,合并畸胎瘤5例。所有病例均经化验血液和(或)脑脊液抗NMDA受体抗体阳性而确诊,脑脊液可见以淋巴细胞为主的白细胞数轻度升高。头MRI检查及脑电图无特异性所见。本文报道的2例患者尚发现血液抗链球菌溶血素O均升高。本文报道的2例患者及文献检索的20例患者经大剂量激素联合丙种球蛋白治疗后(20/23,86.9%)症状明显改善,2例症状改善不明显,1例死亡。结论抗N-甲基-D-天冬氨酸受体脑炎临床表现无特异性,早期易误诊为精神障碍性疾病,脑脊液抗NMDA受体抗体检测有助于早期诊断和治疗,大部分患者免疫治疗有效。本文报道的2例病例尚合并ASO升高,文献中未见报道。     

应激与N-甲基-D-天冬氨酸受体关系的研究进展

应激与中枢谷氨酸神经系统,特别是NMDA(N-甲基-D-天冬氨酸)受体功能有关.本文就应激与NMDA受体关系进行较系统的综述.     

孔圣枕中丹对血管性痴呆的神经保护

临床研究已证实,孔圣枕中丹作为《千金要方》中的经典处方,对血管性痴呆的显著的治疗效果,但其作用机制仍需进一步明确。由此,我们应用原位杂交技术、分光光度法、流式细胞术分别检测大鼠脑组织N-甲基-D-天门冬氨酸受体1 mRNA表达、一氧化氮含量和钙离子浓度,通过免疫组化法检测大鼠脑组织N-甲基-D-天门冬氨酸受体1, GDNF和NGF蛋白表达。结果发现,孔圣枕中丹可明显降低血管性痴呆大鼠脑组织N-甲基-D-天门冬氨酸受体1基因和蛋白的表达,一氧化氮含量和钙离子浓度;提高血管性痴呆大鼠海马和大脑皮质神经生长因子、胶质细胞源性神经营养因子蛋白表达。我们还通过Morris水迷宫和被动避暗试验验证了临床上孔圣枕中丹对血管性痴呆后认知功能障碍的改善作用。实验证实,孔圣枕中丹可通过抑制N-甲基-D-天门冬氨酸诱导的兴奋性神经毒性、提高神经营养因子含量,起到改善血管性痴呆大鼠认知功能的作用。     

难治性癫痫基因靶向治疗研究进展

目前难治性癫痫的基因治疗策略主要通过调节神经递质网络、神经肽Y和神经营养因子等以发挥抗癫痫作用。其中研究较为热门的靶点包括γ-氨基丁酸及其受体、N-甲基-D-天冬氨酸及其受体、甘丙肽、神经肽Y和神经营养因子等。本文就上述靶点的主要研究结果、各研究的优劣做简要介绍,以为临床解决难治性癫痫提供证据。     

抗N-甲基-D-天冬氨酸受体脑炎1例报告

目的加强对抗N-甲基-D-天冬氨酸(NMDA)受体脑炎的进一步的认识。方法收集1例抗N-甲基-D-天冬氨酸受体脑炎患者的临床资料及诊治经过,总结其临床特点及诊疗方法。结果患者为青年男性,以癫痫发作、精神行为异常、认知障碍为主要表现,脑脊液和血清中抗NMDA受体抗体阳性。经激素冲击、静脉用免疫球蛋白、对症处理等治疗后症状好转出院。结论抗NMDAR脑炎是一种自身免疫性脑炎,临床表现复杂多样,血清和脑脊液抗NMDAR抗体检测为该病的特异性检查项目。早期明确诊断和治疗往往预后良好。     

多发性硬化合并抗NMDAR脑炎重叠综合征1例报告及文献复习

正抗N-甲基-D-天冬氨酸受体(N-methyl-Daspartate receptor,NMDAR)抗体相关脑炎是边缘系统中最常见的一种,是一种致死性的疾病,但也是可治疗的免疫性疾病,以显著的精神症状、运动障碍和癫痫发作,通常演变为严重的脑病,     

难治性癫基因靶向治疗研究进展

目前难治性癫的基因治疗策略主要通过调节神经递质网络、神经肽Y和神经营养因子等以发挥抗癫作用。其中研究较为热门的靶点包括γ-氨基丁酸及其受体、N-甲基-D-天冬氨酸及其受体、甘丙肽、神经肽Y和神经营养因子等。本文就上述靶点的主要研究结果、各研究的优劣做简要介绍,以为临床解决难治性癫提供证据。     

N-甲基-D-天冬氨酸受体亚单位2B特异性拮抗剂对缺氧缺血性脑损伤新生大鼠脑室下区神经干细胞增殖的影响

目的:研究N-甲基-D-天冬氨酸受体(NMDAR)亚单位2B(NR2B)特异性拮抗剂(Ro 25-6981)对缺氧缺血性脑损伤(HIBD)新生大鼠脑室下区(SVZ)神经干细胞(NSCs)增殖的影响。方法:7 d龄新生SD大鼠随机分为Ro 25-6981组(HIBD前2 h,腹腔注射Ro 25-6981 10 mg.kg-1)、HIBD组(HIBD前2 h,腹腔注射等剂量生理盐水)和假手术组(仅游离右侧颈总动脉,不结扎)。采用免疫组化学染色检测SVZ Nestin表达量及BrdU阳性细胞数的变化。结果:HIBD组12h后Nestin表达量开始增多,48 h达峰值,之后缓慢下降;与其相比,Ro 25-6981组在12 h和24 h时下降明显(P<0.05)。HIBD组BrdU阳性细胞数在缺氧缺血3 h后缓慢上升,72 h达高峰;与其相比,Ro 25-6981组在各时间点BrdU阳性细胞表达均有所下降,以24、48和72 h减少明显,尤以72 h为著(P<0.05)。结论:Ro 25-6981能够降低HIBD新生大鼠SVZ Nestin的表达及Brdu阳性细胞数,对SVZ NSCs增殖起抑制作用,提示NR2B参与并促进HIBD引起的SVZ NSCs的增殖。     

Pituitary adenylate cyclase-activating polypeptide counteracts the impaired adult neural stem cell viability induced by palmitate

Diabetes and obesity are characterized by hyperlipidemia and represent risk factors for premature neurological disorders. Diabetic/obese animals have impaired adult neurogenesis. We hypothesize that lipotoxicity leading to neurogenesis impairment plays a role in the development of neurological complications. If so, normalizing neurogenesis in diabetes/obesity could be therapeutically useful in counteracting neurological dysfunction. The goal of this study was to determine the potential of pituitary adenylate cyclase-activating polypeptide (PACAP) to protect adult neural stem cells (NSCs) from lipotoxicity and to study the expression of PACAP receptors in NSCs under lipotoxic conditions in vitro and in the subventricular zone in vivo. The viability of NSCs isolated from the adult mouse brain subventricular zone was assessed in the presence of a high-fat milieu, as mimicked by palmitate, which characterizes diabetic lipotoxicity. Regulation studies of PACAP receptors were performed by quantitative PCR on NSCs in vitro or on subventricular tissues isolated from obese ob/ob mice and their lean littermates. We show that palmitate impairs NSC viability by promoting lipoapoptosis. We also show that PACAP counteracts lipotoxicity via PAC-1 receptor activation. Studies on PACAP receptor expression revealed that PAC-1 and VPAC-2 are expressed by NSC in vitro and are upregulated by palmitate treatment and that PAC-1, VPAC-1, and VPAC-2 are expressed in the subventricular zone/striatum in vivo and are upregulated in ob/ob mice. The present study reveals a previously uncharacterized role of PACAP to protect NSC from lipotoxicity and suggests a potential therapeutic role for PACAP receptor agonists in the treatment of neurological complications in obesity and diabetes.     

Directional induction of dopaminergic neurons from neural stem cells using substantia nigra homogenates and basic fibroblast growth factor

To date, complex components of available reagents have been used for directional induction of neural stem cells into dopaminergic neurons, resulting in a poor ability to repeat experiments. This study sought to investigate whether a homogenate of the substantia nigra of adult rats and/or basic fibroblast growth factor could directionally induce neural stem cells derived from the subventricular zone of embryonic rats to differentiate into dopaminergic neurons. Tyrosine hydroxylase-positive cells were observed exclusively after induction with the homogenate supernatant of the substantia nigra from adult rats and basic fibroblast growth factor for 48 hours in vitro. However, in the groups treated with homogenate supernatant or basic fibroblast growth factor alone, tyrosine hydroxylase expression was not observed. Moreover, the content of dopamine in the culture medium of subventricular zone neurons was significantly increased at 48 hours after induction with the homogenate supernatant of the substantia nigra from adult rats and basic fibroblast growth factor. Experimental findings indicate that the homogenate supernatant of the substantia nigra from adult rats and basic fibroblast growth factor could directionally induce neural stem cells derived from the subventricular zone of embryonic rats to differentiate into dopaminergic neurons in the substantia nigra with the ability to secrete dopamine.     

Peptide hormone exendin-4 stimulates subventricular zone neurogenesis in the adult rodent brain and induces recovery in an animal model of Parkinson's disease

We investigated the effects of exendin-4 on neural stem/progenitor cells in the subventricular zone of the adult rodent brain and its functional effects in an animal model of Parkinson's disease. Our results showed expression of GLP-1 receptor mRNA or protein in the subventricular zone and cultured neural stem/progenitor cells isolated from this region. In vitro, exendin-4 increased the number of neural stem/progenitor cells, and the number of cells expressing the neuronal markers microtubule-associated protein 2, β-III-tubulin, and neuron-specific enolase. When exendin-4 was given intraperitoneally to naïve rodents together with bromodeoxyuridine, a marker for DNA synthesis, both the number of bromodeoxyuridine-positive cells and the number of neuronal precursor cells expressing doublecortin were increased. Exendin-4 was tested in the 6-hydroxydopamine model of Parkinson's disease to investigate its possible functional effects in an animal model with neuronal loss. After unilateral lesion and a 5-week stabilization period, the rats were treated for 3 weeks with exendin-4. We found a reduction of amphetamine-induced rotations in animals receiving exendin-4 that persisted for several weeks after drug administration had been terminated. Histological analysis showed that exendin-4 significantly increased the number of both tyrosine hydroxylase- and vesicular monoamine transporter 2-positive neurons in the substantia nigra. In conclusion, our results show that exendin-4 is able to promote adult neurogenesis in vitro and in vivo, normalize dopamine imbalance, and increase the number of cells positive for markers of dopaminergic neurons in the substantia nigra in a model of Parkinson's disease. © 2007 Wiley-Liss, Inc.     

Characterization of the Netrin/RGMa receptor neogenin in neurogenic regions of the mouse and human adult forebrain

In the adult rodent forebrain, astrocyte‐like neural stem cells reside within the subventricular zone (SVZ) and give rise to progenitors and neuroblasts, which then undergo chain migration along the rostral migratory stream (RMS) to the olfactory bulb, where they mature into fully functional interneurons. Neurogenesis also occurs in the adult human SVZ, where neural precursors similar to the rodent astrocyte‐like stem cell and neuroblast have been identified. A migratory pathway equivalent to the rodent RMS has also recently been described for the human forebrain. In the embryo, the guidance receptor neogenin and its ligands netrin‐1 and RGMa regulate important neurogenic processes, including differentiation and migration. We show in this study that neogenin is expressed on neural stem cells (B cells), progenitor cells (C cells), and neuroblasts (A cells) in the adult mouse SVZ and RMS. We also show that netrin‐1 and RGMa are ideally placed within the neurogenic niche to activate neogenin function. Moreover, we find that neogenin and RGMa are also present in the neurogenic regions of the human adult forebrain. We show that neogenin is localized to cells displaying stem cell (B cell)‐like characteristics within the adult human SVZ and RMS and that RGMa is expressed by the same or a closely apposed cell population. This study supports the hypothesis that, as in the embryo, neogenin regulates fundamental signalling pathways important for neurogenesis in the adult mouse and human forebrain. J. Comp. Neurol. 518:3237–3253, 2010. © 2010 Wiley‐Liss, Inc.     

Early expressions of hypoxia-inducible factor 1alpha and vascular endothelial growth factor increase the neuronal plasticity of activated endogenous neural stem cells after focal cerebral ischemia

Endogenous neural stem cells become "activated" after neuronal injury, but the activation sequence and fate of endogenous neural stem cells in focal cerebral ischemia model are little known. We evaluated the relationships between neural stem cells and hypoxia-inducible factor-1α and vascular endothelial growth factor expression in a photothromobotic rat stroke model using immunohistochemistry and western blot analysis. We also evaluated the chronological changes of neural stem cells by 5-bromo-2′-deoxyuridine(BrdU) incorporation. Hypoxia-inducible factor-1α expression was initially increased from 1 hour after ischemic injury, followed by vascular endothelial growth factor expression. Hypoxia-inducible factor-1α immunoreactivity was detected in the ipsilateral cortical neurons of the infarct core and peri-infarct area. Vascular endothelial growth factor immunoreactivity was detected in bilateral cortex, but ipsilateral cortex staining intensity and numbers were greater than the contralateral cortex. Vascular endothelial growth factor immunoreactive cells were easily found along the peri-infarct area 12 hours after focal cerebral ischemia. The expression of nestin increased throughout the microvasculature in the ischemic core and the peri-infarct area in all experimental rats after 24 hours of ischemic injury. Nestin immunoreactivity increased in the subventricular zone during 12 hours to 3 days, and prominently increased in the ipsilateral cortex between 3–7 days. Nestin-labeled cells showed dual differentiation with microvessels near the infarct core and reactive astrocytes in the peri-infarct area. BrdU-labeled cells were increased gradually from day 1 in the ipsilateral subventricular zone and cortex, and numerous BrdU-labeled cells were observed in the peri-infarct area and non-lesioned cortex at 3 days. BrdU-labeled cells rather than neurons, were mainly co-labeled with nestin and GFAP. Early expressions of hypoxia-inducible factor-1α and vascular endothelial growth factor after ischemia made up the microenvironment to increase the neuronal plasticity of activated endogenous neural stem cells. Moreover, neural precursor cells after large-scale cortical injury could be recruited from the cortex nearby infarct core and subventricular zone.     

A ginkgo biloba extract promotes proliferation of endogenous neural stem cells in vascular dementia rats

The ginkgo biloba extract EGb761 improves memory loss and cognitive impairments in patients with senile dementia. It also promotes proliferation of neural stem cells in the subventricular zone in Parkinson’s disease model mice and in the hippocampal zone of young epileptic rats. However, it remains unclear whether EGb761 enhances proliferation of endogenous neural stem cells in the brain of rats with vascular dementia. In this study, a vascular dementia model was established by repeatedly clipping and reperfusing the bilateral common carotid arteries of rats in combination with an intraperitoneal injection of a sodium nitroprusside solution. Seven days after establishing the model, rats were intragastrically given EGb761 at 50 mg/kg per day. Learning and memory abilities were assessed using the Morris water maze and proliferation of endogenous neural stem cells in the subventricular zone and dentate gyrus were labeled by 5-bromo-2-deoxyuridine immunofluorescence in all rats at 15 days, and 1, 2, and 4 months after model establishment. The escape latencies in Morris water maze tests of rats with vascular dementia after EGb761 treatment were significantly shorter than the model group. Immunofluorescence staining showed that the number and proliferation of 5-bromo-2-deoxyuridine-positive cells in the subventricular zone and dentate gyrus of the EGb761-treated group were significantly higher than in the model group. These experimental findings suggest that EGb761 enhances proliferation of neural stem cells in the subventricular zone and dentate gyrus, and significantly improves learning and memory in rats with vascular dementia.     

Comparative characterization of the human and mouse third ventricle germinal zones

Recent evidence indicates differences in neural stem cell biology in different brain regions. For example, we demonstrated that neurofibromatosis 1 (NF1) tumor suppressor gene inactivation leads to increased neural stem cell proliferation and gliogenesis in the optic chiasm and brainstem but not in the cerebral cortex. The differential effect of Nf1 inactivation in the optic nerve and brainstem (in which gliomas commonly form in children with NF1) versus the cortex (in which gliomas rarely develop) suggests the existence of distinct ventricular zones for gliomagenesis in children and in adults. Here, we characterized the third ventricle subventricular zone (tv-SVZ) in young and adult mouse and human brains. In children, but not adult humans, the tv-SVZ contains nestin-positive, glial fibrillary acidic protein-positive, brain fatty acid binding protein-positive, and sox2-positive cells with radial processes and prominent cilia. In contrast, the tv-SVZ in young mice contains sox2-positive progenitor cells and ciliated ependymal lining cells but lacks glial fibrillary acidic protein-positive, nestin-positive radial glia. As in the lateral ventricle SVZ, proliferation in the human and murine tv-SVZ decreases with age. The tv-SVZ in adult mice lacks the hypocellular subventricular zone observed in adult human specimens. Collectively, these data indicate the existence of a subventricular zone relevant to our understanding of glioma formation in children and will assist interpretation of genetically engineered mouse glioma models.