海马NMDA受体在认知障碍中的研究进展

海马中含有丰富的N-甲基-D-天冬氨酸（NMDA）受体，它介导了与认知功能密切相关的长时程增强（LTP）和长时程抑制（LTD）。NMDA受体的激活既能起到神经保护的作用，又具有神经毒性，其原因可以通过定位模型和亚基组成模型来解释。但是模型只能相对宏观地概括NMDA受体激活后呈现的差异，在不同疾病中，NMDA受体的变化呈现出其独特的特点。本文以帕金森病、阿尔茨海默病、精神分裂症与抗NMDA受体脑炎为例，探讨海马NMDA受体在不同疾病认知障碍中的改变，针对性地调节海马NMDA受体亚基的功能水平可能有望作为治疗疾病认知障碍的潜在靶点。     

慢性酒精中毒及戒断对大鼠海马NMDA受体亚基NR2B表达的影响

目的观察慢性酒精中毒及戒断对大鼠海马内N-甲基-D-天冬氨酸(NMDA)受体亚基NR2B(NMDAR2B)表达的变化。方法本研究将56只成年雄性大鼠随机分为6个实验组各8只和对照组8只,前者包括5个50%酒精灌胃组和1个15%酒精灌胃组,连续给予灌胃8周;8周后5个50%酒精灌胃组分为未戒断组、戒断36h组、戒断3d组、戒断1周组和戒断2周组。用柳田知司评分法评定戒断症状,采用免疫组织化学方法检测NMDAR2B的表达水平。结果①大鼠灌胃50%酒精8周后可观察到戒断反应;②50%和15%酒精灌胃组NMDAR2B受体表达水平均较对照组增多(P<0.05);③50%酒精灌胃组戒断后36h、3d和1周NMDAR2B水平上调,均较对照组明显增多(P<0.05),并在3d时达到高峰,此后开始下降;④至戒断2周下降至低于对照组,并有统计学意义(P<0.05)。结论给大鼠灌胃50%酒精8周可达到慢性酒精中毒;NMDAR2B表达异常可能是慢性酒精中毒与戒断综合征的重要机制。     

NMDA受体与癫痫发病机制的研究现状

癫痫的主要机制为脑内兴奋性氨基酸活性升高。在癫痫发作中,N-甲基-D-天门冬氨酸(NMDA)受体含量增多,表达升高,且其各个亚型之间相互作用,构形发生变化,使突触后膜支架蛋白磷酸化,发生级联发应,使NMDA受体配体离子通道持续开放,神经元持续放电,并向周围神经元放散扩布;长期癫痫反复发作,导致苔藓纤维发芽,神经元缺失;这些形态学和电生理改变,反之,导致癫痫的易感和反复发作。通过多年动物实验和临床应用,提示N-甲基-D-冬氨酸受体亚单位2B(NR2B),高选择性的拮抗剂有广阔的临床应用前景。     

NMDA受体在神经系统损伤中的应用

在外伤性神经系统损伤中,比较多见的是脑组织损伤。目前对脑损伤的病理生理变化,尤其是对N-甲基-D-天冬氨酸(N-methyl-D-asparate,NMDA)-Ca2 -一氧化氮路径的研究[1],运用到神经系统损伤检验中的意义更为迫切和重大。从生理学及病理学的角度研究NMDA-Ca2 -一氧化氮路径的重大意     

丙戊酸通过调控S100B蛋白表达对癫痫幼鼠模型的认知功能及NMDAR1水平的影响

目的 探讨丙戊酸通过调控S100B蛋白表达对癫痫幼鼠模型的认知功能及N-甲基-D-天冬氨酸受体(N-methyl-D-aspartate receptor, NMDAR)1水平的影响。方法 50只幼鼠按随机数字表分为对照组、模型组、丙戊酸组、喷他脒(Pentamidine)组及丙戊酸+Pentamidine组,每组各10只;除对照组外,其余各组幼鼠均建立癫痫模型,建模后丙戊酸组灌胃1 mg/kg丙戊酸,Pentamidine组注射5 mg/kg的Pentamidine及丙戊酸+Pentamidine组灌胃1 mg/kg丙戊酸和尾部注射5 mg/kg的Pentamidine;水迷宫实验检测认知功能;尼氏染色观察海马组织形态;末端脱氧核苷酸转移酶介导的dUTP尾端标记法(Terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling, TUNEL)法检测海马组织神经细胞凋亡率;免疫组化染色检测海马组织NMDAR1阳性细胞率;免疫印记检测海马组织中S100钙结合蛋白B(S100 calcium-binding pro...     

癫痫与NMDA受体的研究进展

癫痫是以脑部神经元超同步化放电导致突然、反复和短暂的中枢神经系统功能失常为特征的神经科临床综合征.根据所侵犯神经元的部位和放电发放扩散的范围,功能失常可表现为运动、感觉、意识、行为和神经功能障碍,或兼而有之.目前关于癫痫的发病机制尚无明确的定论.近来兴奋性神经递质与抑制性神经递质的失衡学说引起了越来越多学者的关注.其中谷氨酸作为中枢内的兴奋性神经递质,被认为在癫痫的发病中起着相当重要的作用.     

神经元移行异常的大鼠脑皮层中NMDA的表达

目的 观察神经元移行异常(neurona1 migration disorders,NMDs)动物模型脑组织的病理变化以及N-甲基-D-天门冬氨酸受体(n-methyl-d-aspartate receptor,NMDA)的表达.方法 三组Sprague-Dawley孕鼠分别在孕15天,孕17天以及孕19天接受2.25Gy的X射线照射约5分钟,其后代成年后即为NMDs动物模型.观察指标为:存活率、脑组织的病理变化以及皮层中NMDA的表达.结果 胚胎期较早接受射线的大鼠,存活率低,大脑皮层结构紊乱严重,皮层NRl和NR2A的表达高.结论 在NMDs的大鼠脑皮层中,NRl和NR2A表达增加,且其表达增加的程度能反映NMDs的严重程度.NMDA的上调可能是NMDs患者致痫的主要病因.     

儿童抗NMDA受体脑炎临床分析

目的探讨儿童抗N-甲基-D-天冬氨酸(NMDA)受体脑炎的临床特点及文献回顾。方法回顾性分析山东大学齐鲁儿童医院神经内科2017-01—2018-12治疗的9例抗NMDA受体脑炎患儿的临床资料。结果 9例确诊为抗NMDA受体脑炎的患儿纳入研究,女6例,男3例,发病年龄1岁5个月～13岁,首发症状不一,其中惊厥发作6例,运动障碍2例,意识障碍1例。血和(或)脑脊液抗NMDA受体抗体阳性,均接受静点免疫球蛋白及甲泼尼龙治疗,3例予利妥昔单抗治疗。8例恢复良好,1例复发,无死亡。结论抗NMDA受体脑炎可发生于儿童各年龄段,临床特征与成人相似,合并肿瘤者少见,怀疑或确诊后应尽早开始免疫治疗,总体预后良好,利妥昔单抗治疗难治或复发的患儿安全有效。     

马桑内酯致痫大鼠大脑皮层、海马NMDA受体亚单位1(NMDAR1)mRNA表达的变化

目的　探讨癫痫发病的分子机制。方法　采用原位杂交技术 ,研究了马桑内酯致痫大鼠大脑皮层、海马 N-甲基 - D-天门冬氨酸受体亚单位 1(NMDAR1) m RNA表达的变化。结果　马桑内酶致痫大鼠顶叶大脑皮层及海马齿状回 NMDAR1m RNA水平显著高于生理盐水对照组 (P<0 .0 1,P<0 .0 5 )。结论　马桑内酯上调脑组织内NMDAR1m RNA水平 ,此可能是其致痫及惊厥易感性增加的分子机制之一     

钙神经素在癫痫中的作用研究

钙神经素(CaN)是迄今发现的唯一受Ca2+/钙调素(CaM)调节的丝氨酸/苏氨酸蛋白质磷酸酶。CaN在神经系统含量丰富,参与细胞的多种生理病理过程。许多动物实验提示在癫痫的发生和发展中,涉及到CaN的激活和N-甲基-D-天门冬氨基酸(NMDA)受体的活化,同时,CaN还可调节-氨酸丁酸(GABA)受体介导的抑制作用,与许多凋亡分子如钙蛋白酶(calpain)、bcl-2相关的死亡蛋白、caspase途径相关蛋白及一氧化氮合酶(NOS)之间发生广泛的作用。本文就CaN在癫痫中的作用作一综述。     

Involvement of NMDA receptors in ryanodine receptor expression in dopaminergic neurons in the ventral tegmental area of mice with intermittent methamphetamine treatment

Excitatory synapses on dopaminergic neurons of the ventral tegmental area (VTA) represent an important role in psychostimulant-induced rewarding effect. This study investigated the regulation of ryanodine receptor (RyR) and N-methyl-D-aspartate (NMDA) receptor expression in mice under intermittent methamphetamine (METH) treatment using a place preference procedure. RyR-1 and -2 significantly increased in the VTA of mice with METH-induced place preference, whereas RyR-3 showed no changes. In addition, the levels of NR1, NR2A, and NR2B subunits were increased in the VTA. The METH-induced place preference was inhibited by intracerebroventricular pretreatment with MK-801, a noncompetitive NMDA receptor antagonist, and ifenprodil, a selective NR2B subunit-containing NMDA receptor antagonist, in a dose-dependent manner. Under these conditions, the increase of RyR-1 and -2 in the VTA was significantly blocked by ifenprodil. The immunohistochemical analysis revealed the colocalization of RyR-1 and -2 with NR2B subunits in dopaminergic neurons in the mouse VTA. These findings suggest that RyRs could be involved in the development of METH-induced place preference and that NR2B subunit-containing NMDA receptors in mice showing METH-induced place preference play an important role in expression of RyRs.     

The NMDA receptor complex as a therapeutic target in epilepsy: a review

A substantial amount of research has shown that N-methyl-D-aspartate receptors (NMDARs) may play a key role in the pathophysiology of several neurological diseases, including epilepsy. Animal models of epilepsy and clinical studies demonstrate that NMDAR activity and expression can be altered in association with epilepsy and particularly in some specific seizure types. NMDAR antagonists have been shown to have antiepileptic effects in both clinical and preclinical studies. There is some evidence that conventional antiepileptic drugs may also affect NMDAR function. In this review, we describe the evidence for the involvement of NMDARs in the pathophysiology of epilepsy and provide an overview of NMDAR antagonists that have been investigated in clinical trials and animal models of epilepsy.     

CA3 NMDA receptors are required for experience-dependent shifts in hippocampal activity

The anatomical distribution of sensory-evoked activity recorded from the hippocampal long-axis can shift depending on prior experience. In accordance with Marr's computational model of hippocampal function, CA3 NMDA receptors have been hypothesized to mediate this experience-dependent shift in hippocampal activity. Here we tested this hypothesis by investigating genetically-modified mice in which CA3 NMDA receptors are selectively knocked-out (CA3-NR1 KO). First, we were required to develop an fMRI protocol that can record sensory-evoked activity from the mouse hippocampal long-axis. This goal was achieved in part by using a dedicated mouse scanner to image odor-evoked activity, and by using non-EPI (echo planer imaging) pulse sequences. As in humans, odors were found to evoke a ventral-predominant activation pattern in the mouse hippocampus. More importantly, odor-evoked activity shifted in an experience-dependent manner. Finally, we found that the experience-dependent shift in hippocampal long-axis activity is blocked in CA3-NR1 knock-out mice. These findings establish a cellular mechanism for the plasticity imaged in the hippocampal long-axis, suggesting how experience-dependent modifications of hippocampal activity can contribute to its mnemonic function.     

海马NMDA受体调节严重烫伤应激后HPA轴兴奋性的相关机制研究

目的探寻海马N-甲基-D-天冬氨酸(NMDA)受体调节严重创伤应激后HPA轴过度兴奋的可能机制。方法以30%总体表面积(TBSA)Ⅲ度烫伤应激作为严重创伤应激模型,先通过地塞米松抑制试验检测严重烫伤应激后糖皮质激素(GC)负反馈功能的变化,再利用RT-PCR技术检测烫伤应激后海马糖皮质激素受体(GR)mRNA水平(其水平与负反馈功能密切相关)的变化特点,并观察烫伤应激前腹腔注射NMDA受体拮抗剂MK-801对烫伤应激后2hGRmRNA水平的影响。结果30%TBSAⅢ度烫伤应激后地塞米松抑制试验阴性,GC负反馈功能下降;烫伤应激后0.5、2、8、24、48h海马GRmRNA水平皆明显降低,尤以伤后2h最明显;与烫伤应激组相比,MK-8013mg/kg组GRmRNA水平显著上升,MK-8016mg/kg组海马GRmRNA水平进一步上升,盐水组GRmRNA水平无明显变化。结论海马NMDA受体调节严重烫伤应激后HPA轴的亢进是通过下调海马GR从而影响了GC在海马水平的负反馈引起的。     

NMDA receptor blockade ameliorates abnormalities of spike firing of subthalamic nucleus neurons in a parkinsonian nonhuman primate

N‐methyl‐D‐aspartate receptors (NMDARs) are ion channels comprising tetrameric assemblies of GluN1 and GluN2 receptor subunits that mediate excitatory neurotransmission in the central nervous system. Of the four different GluN2 subunits, the GluN2D subunit‐containing NMDARs have been suggested as a target for antiparkinsonian therapy because of their expression pattern in some of the basal ganglia nuclei that show abnormal firing patterns in the parkinsonian state, specifically the subthalamic nucleus (STN). In this study, we demonstrate that blockade of NMDARs altered spike firing in the STN in a male nonhuman primate that had been rendered parkinsonian by treatment with the neurotoxin 1‐methyl‐4‐phenyl‐1,2,3,6‐tetrahydropyridine. In accompanying experiments in male rodents, we found that GluN2D‐NMDAR expression in the STN was reduced in acutely or chronically dopamine‐depleted animals. Taken together, our data suggest that blockade of NMDARs in the STN may be a viable antiparkinsonian strategy, but that the ultimate success of this approach may be complicated by parkinsonism‐associated changes in NMDAR expression in the STN.     

Caspase3基因克隆及在癫痫样放电海马神经元中的表达

目的 探讨海马神经元癫痫样放电引起神经元丢失的机制。方法 采用RT—PCR法克隆大鼠全长Caspase3cDNA，然后采用原位杂交和流式细胞技术检测了海马神经元癫痫模型中Caspase3基因表达和神经元凋亡情况。结果 得到了大鼠的全长Caspase3cDNA，发现海马神经元癫痫样放电后出现Caspase3基因表达和神经元凋亡的现象。结论 癫痫样放电启动Caspase3表达，继而介导神经元凋亡。     

Developmental changes in localization of NMDA receptor subunits in primary cultures of cortical neurons

Immunoblot analysis, using antibodies against distinct N-methyl-d -aspartic acid (NMDA) receptor subunits, illustrated that the NR2A and NR2B subunit proteins have developmental profiles in cultured cortical neurons similar to those seen in vivo. NR1 and NR2B subunits display high levels of expression within the first week. In contrast, the NR2A subunit is barely detectable at 7 days in vitro (DIV) and then gradually increased to mature levels at DIV21. Immunocytochemical analysis indicated that NMDA receptor subunits cluster in the dendrites and soma of cortical neurons. Clusters of NR1 and NR2B subunits were observed as early as DIV3, while NR2A clusters were rarely observed before DIV10. At DIV18, NR2B clusters partially co-localize with those of NR2A subunits, but NR2B clusters always co-localize with those of NR1 subunits. Synapse formation, as indicated by the presence of presynaptic synaptophysin staining, was observed as early as 48–72 h after plating. However, in several neurons at ages less than DIV5 where synapses were scarce, NR2B and NR1 clusters were abundant. Furthermore, while NR2B subunit clusters were seen both at synaptic and extrasynaptic sites, NR2A clusters occurred almost exclusively in front of synaptophysin-labelled boutons. This result was supported by electrophysiological recording of NMDA-mediated synaptic activity [NMDA-excitatory postsynaptic currents (EPSCs)] in developing neurons. At DIV6, but not at DIV12, CP101, 606, a NR1/NR2B receptor antagonist, antagonized spontaneously occurring NMDA-EPSCs. Our data indicate that excitatory synapse formation occurs when NMDA receptors comprise NR1 and NR2B subunits, and that NR2A subunits cluster preferentially at synaptic sites.     

Caspase3基因克隆及在癫痫样放电海马神经元中的表达

目的 探讨海马神经元癫痫样放电引起神经元丢失的机制。方法 采用RT-PCR法克隆大鼠全长Caspase3 cDNA，然后采用原位杂交和流式细胞技术检测了海马神经元癫痫模型中Caspase3基因表达和神经元凋亡情况。结果 获得了大鼠的全长CasPase3工业cDNA．发现海马神经元癫痫样放电后出现Caspase3基因表达和神经元凋亡的现象。结论 癫痫样放电启动Caspase3表达，继而介导神经元凋亡。     

Survival and synaptogenesis of hippocampal neurons without NMDA receptor function in culture

Physiological and morphological properties of cultured hippocampal neurons were measured to investigate whether NMDA receptors play a role in survival and differentiation. Neurons dissociated from mouse embryos with different NMDAR1 genotypes were grown in culture. Electrophysiological analysis verified the absence of NMDA receptor-mediated currents in neurons taken from homozygous mutant (NR1–/–) embryos. The number of surviving hippocampal neurons was 2.5-fold higher in cultures from the NR1–/– embryos compared with wild type (NR1 +/+) and heterozygous (NR1+/–) controls. Despite the lack of NMDA receptor function, NR1–/– neurons formed synapsin I-positive presynaptic boutons associated with MAP2ab-positive dendrites in culture. Confocal microscopic analysis of DiI labelled neurons confirmed the presence of dendritic spines on NR1–/– neurons with 80% of the density found in NR1 +/+ neurons. These results suggest that the NMDA receptor has little effect on general features of neuronal differentiation. In contrast, there is clear effect on neuronal survival. This finding establishes neuron number in standard culture conditions as a measure of NMDA receptor activity.