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1.
谷氨酸下调培养海马神经元AMPA受体G1uR2亚单位的表达   总被引:1,自引:0,他引:1  
目的 研究在癫痫发病过程中,谷氨酸对AMPA受体G1uR2亚单位表达变化的影响。方法 用RT-PCR和Western Blot方法观察谷氨酸诱导培养大鼠海马神经元AMPA受体G1uR2亚单位mRNA和蛋白的表达变化。结果 在谷氨酸刺激后2h,8h,12h,培养海马神经元G1uR2 mRNA和蛋白表达明显下降,与对照组相比,差异有显著性(P〈0.05),而非NMDA受体拮抗剂CNQX能阻断此变化。结论 在癫痫等疾病中,谷氨酸能通过激活AMAP/KA受体下调AMPA受体G1uR2亚单位的表达,参与发病过程。  相似文献   

2.
海仁酸致痫大鼠海马组织AMPA受体GluR2表达的变化   总被引:4,自引:2,他引:4  
目的 为了研究AMPA受体在癫痫发生中的作用。方法 本研究用免疫组织化学方法观察了海仁酸致痫大鼠海马组织AMPA GluR2受体的表达变化。结果 在侧脑室注射海仁酸后 1h ,4h ,12h ,2 4h及 7d ,大鼠海马CA3区及齿状回GluR2的表达明显减弱 ,显微图像分析 :与对照组相比 ,KA 4h ,KA 12h ,KA 2 4h ,KA 7d组大鼠海马组织GluR2阳性神经元平均光密度值降低 ,差异有显著性 (P <0 0 5 )。结论 在癫痫发作过程中AMPA受体 GluR2亚单位表达改变可能与癫痫发作导致的神经元损伤有密切关系。  相似文献   

3.
目的探讨星形胶质细胞对大鼠脑内谷氨酸(Glu)和γ-氨基丁酸(GABA)的影响及其在癫痫发病中的作用。方法将马桑内酯激活的星形胶质细胞条件培养液(astrocyte-conditioned medium,ACM)注射入正常SD大鼠侧脑室,观察大鼠的行为变化,运用免疫组织化学及HPLC的方法,观察大鼠大脑皮质、海马内Glu和GABA免疫反应的变化及脑组织匀浆、脑脊液内Glu和GABA含量的变化。结果ACM组大鼠在注射ACM后30min出现癫痫行为,2h恢复正常。免疫组织化学显示:ACM作用后2h,大鼠大脑皮质及海马内Glu免疫反应阳性神经元数和平均光密度值明显增高,4h达高峰(P<0.05),12h恢复正常水平;ACM作用后2h,大鼠大脑皮质及海马GABA免疫反应阳性神经元数和平均光密度值明显减弱(P<0.05),12h恢复正常水平。HPLC方法显示:ACM作用后2h大鼠大脑皮质、海马及脑脊液中Glu含量均开始增加,4h达高峰(P<0.05);ACM作用后2h大脑皮质、海马及脑脊液中GABA含量均开始降低,4h达最低(P<0.05)。结论马桑内酯激活的星形胶质细胞条件培养液可影响大鼠脑内Glu和GABA的表达,并导致动物痫性发作。  相似文献   

4.
目的观察海人酸(kainic acid,KA)所致癫痫(epilepsy,EP)小鼠海马Ste20蛋白激酵素(MST3)表达水平的变化,探讨MST3在癫痫发病过程中的可能作用。方法选用成年雄性小鼠,并随机分成模型组和对照组。模型组小鼠侧脑室注射2μL(100 ng/μL)KA,分别于术后3、8、24 h收集动物标本以进行检测。使用RT-PCR和Western Blot测定MST3 mRNA含量和MST3蛋白动态表达变化,应用免疫组化观察MST3在海马的表达分布与特点。结果与正常对照组相比,模型组海马组织内MST3mRNA的表达随时间持续升高,24 h达到高峰;MST3的蛋白表达也表现出同样的动态升高趋势;术后3~24 h的模型组海马免疫组化检测显示,模型组MST3主要以海马齿状回、门回区、CA3区域表达增加为主,并且这些区域表达逐渐递增。结论随着时间的推移,MST3表达水平呈现逐渐增加趋势,可能与神经元损伤造成的凋亡之间有密切的关系,提示MST3可能在癫痫发病过程中起重要作用。  相似文献   

5.
大脑中神经元突触间的信号传递是由许多神经递质受体介导的。在过去,Richard L.Huganir实验室一直致力于神经递质受体功能调节的分子机制。而最近,该实验室又聚焦到大脑中一种最主要的兴奋性受体的研究——谷氨酸受体。谷氨酸受体主要可以分为两大类:AMPA受体和NMDA受体。AMPA受体主要介导了快速的兴奋性突触传递;而NMDA受体则在神经可塑性和发育中起到重要作用。实验发现,AMPA受体和NMDA受体都可以被一系列的蛋白激酶磷酸化,而磷酸化的水平则直接影响了这些受体的功能特性,包括通道电导和受体膜定位等。AMPA受体磷酸化的水平同时还在学习和记忆的细胞模型中发生改变,如长时程增强(LTP)和长时程抑制(LTD)。此外,AMPA受体中GluR1亚单位的磷酸化对于各种形式的可塑性以及空间记忆的维持有重要的作用。实验室主要研究突触部位谷氨酸受体在亚细胞水平的定位和聚集的分子机制。最近,一系列可以直接或间接与AMPA和NMDA受体相互作用的蛋白质得以发现,其中包括一个新发现的蛋白家族GRIPs(glutamate receptor interacting proteins)。GRIPs可以直接和AMPA受体的GluR2/3亚单位的C端结合。GRIPs包含7个PDZ结构域,可以介导蛋白与蛋白直接的相互连接,从而把各个AMPA受体交互连接在一起并与其他蛋白相连。另外,GluR2亚单位的c端还可以和兴奋性突触中的蛋白激酶C结合蛋白(PICK1)的PDZ结构域相互作用。另外,GluR2亚单位的C端也可以与一种参与膜融合的蛋白NSF相互作用。这些与AMPA受体相互作用的蛋白质对于受体在膜上的运输以及定位有至关重要的作用。同时,受体与PICK1和GRIP的结合对于小脑运动学习中的LTD有重要作用。总体上说,该实验室发现了一系列可以调节神经递质受体功能的分子机制,这些工作提示受体功能的调节可能是?  相似文献   

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目的探讨激活的星形胶质细胞条件培养液(astrocytic conditioned medium,ACM)的致痫效应及其对脑内谷氨酸(Glu)和白细胞介素-2受体(interleukin-2recepter,IL-2R)表达的影响。方法本研究通过体外分离纯化培养,获取大鼠大脑皮质星形胶质细胞(Ast),用睫状神经营养因子(cliary neurotrophic factor,CNTF)激活Ast,取其培养液。将大鼠随机分为2组:A组(生理盐水对照组)和B组(ACM组)。对大鼠行侧脑室注射相应试剂后,观察并记录大鼠行为,采用免疫组织化学方法检测海马及大脑皮质内Glu的含量及IL-2R的表达变化。结果大鼠在侧脑室注射ACM后,有痫样发作,程度达III-IV级。免疫组化染色显示,在注药后2h,该组的海马区及大脑皮质内Glu、IL-2R免疫应答阳性神经元均较对照组明显增多,免疫应答增强,有显著性差异(P<0.05)。结论星形胶质细胞激活后,其释放物有明显的致痫效应,其机制与促进脑内Glu和IL-2R表达有密切关系。  相似文献   

7.
Hu YE  Zhou AL  Zhu Y  Mao JH  Shi HY 《中国应用生理学杂志》2007,23(3):300-303,I0001
目的:探讨脑益康药物血清对谷氨酸(Glu)诱导的海马神经元损伤的保护作用。方法:大鼠海马神经元培养后,采用形态学观察、MTT法及DAPI染色法检测脑益康药物血清对Glu损伤细胞活力的影响,采用RT-PCR和免疫组化方法检测脑益康药物血清对Glu损伤细胞PTEN表达的影响。结果:脑益康药物血清可明显提高Glu损伤的海马神经元的细胞活力,减少PTEN的表达。结论:脑益康药物血清对Glu诱导的海马神经元损伤有保护作用,其机制可能与减少PTEN表达,抑制神经元凋亡有关。  相似文献   

8.
目的研究癫痫发病时星形胶质细胞的激活及脑和脑脊液兴奋性氨基酸含量的变化.方法将实验SD大鼠随机分为2组:1.生理盐水对照(control)组(n=8);腹腔注射与致痫剂等容量的生理盐水.2.戊四氮(PTZ)组;PTZ 60mg/kg腹腔注射后2h、4h、8h、12h取脑,每个时间点各8只,检测下列指标:(1)用免疫组织化学方法(SABC法)观察大鼠大脑皮质和海马内星形胶质细胞胶质原纤维酸性蛋白(GFAP)含量的变化;(2)用Western blot方法检测大鼠大脑皮质和海马细胞周期素D1(cyclin D1)表达的变化;(3)采用高效液相色谱(HPLC)法测定大鼠大脑皮质和海马组织匀浆及脑脊液中兴奋性氨基酸(天冬氨酸和谷氨酸)含量的变化.结果星形胶质细胞GFAP免疫组织化学染色结果显示癫痫发作4h后在大脑皮质和海马CA3区、CA1区和皮质内GFAP免疫反应明显增强(P<0.05);Western blot检测癫痫发作2h后cyclin D1的表达在皮质和海马均较对照组明显增强(P<0.05);HPLC测定癫痫发作4h后大脑皮质中天冬氨酸(Asp)和谷氨酸(Glu)的含量达到最高峰,分别为8.900±0.540μmol/g protein和17.500±0.526μmol/g protein,与对照组(分别为7.083±0.693μmol/g protein和7.017±0.419μmol/g protein)相比均有显著性差异(P<0.05),在海马内Asp的含量在癫痫发作后2h达到最高峰,为11.425±1.006μmol/g protein,Glu的含量在癫痫发作后4h达到最高峰,为17.698±0.250μmol/g protein,与对照组(分别为7.300±0.824μmol/g protein和10.925±0.323μmol/g protein)比较均有显著性差异(P<0.05),脑脊液中Asp的含量在癫痫发作后2h达到最高峰,为82.65±4.81μmol/L,而Glu的含量在癫痫发作后持续增高,12h后达到72.80±3.66μmol/L.结论戊四氮致痫过程中兴奋性氨基酸含量增多,海马及皮质内星形胶质细胞激活,cyclin D1表达增加,星形胶质细胞增殖,以上变化在癫痫的形成和维持中发挥作用.  相似文献   

9.
目的:观察细胞外调节激酶(ERK)信号通路激活对基质细胞衍生因子(SDF-1)引起离体培养的大鼠海马神经元γ-氨基丁酸(GABA)分泌的影响。方法:新生SD大鼠海马神经元离体培养,Western blot法观察ERK1/2信号通路的磷酸化水平;ELISA法和RT-PCR技术检测ERK1/2特异性阻断剂PD98059作用于离体培养的海马神经元后GABA分泌的改变;谷氨酸脱羧酶(GAD65/67)和γ-氨基丁酸转运体(GAT)的蛋白表达量及GAD65和GAT-1 mRNA表达水平。结果:SDF-1作用于海马神经元可引起ERK1/2磷酸化水平明显升高,同时加用CXCR4受体阻断剂AMD3100,可阻断SDF1引起的ERK1/2激活;SDF-1可明显抑制离体培养的海马神经元GABA的分泌,同时加用ERK1/2特异性抑制剂PD98059,可部分逆转SDF-1对GABA分泌的抑制作用;SDF-1作用于离体培养的海马神经元,可抑制谷氨酸脱羧酶GAD65和GABA转运体GAT-1 mRNA的生成;ERK抑制剂PD98059可有效翻转SDF-1的作用。Western blot结果发现SDF-1可抑制海马神经元GAT-1和GAD65/67蛋白的表达,加用ERK1/2抑制剂可部分恢复GAT-1和GAD65/67蛋白合成。结论:SDF1作用于离体培养的海马神经元CXCR4,通过激活ERK1/2信号通路进而抑制GAD蛋白表达,可能是其介导GABA分泌抑制的通路之一。  相似文献   

10.
Hu ZA  Tan YL  Luo J  Li HD  Li XC  Yu ZP 《生理学报》2004,56(1):89-94
既往研究发现,神经细胞粘附分子(neural cell adhesion molecules,NCAM)对海马CA1区突触传递长时程增强(longterm potentiation,LTP)的诱导和维持极为关键。本文采用原位杂交法和Western blot法,观察了大鼠海马腑片LTP诱导和维持过程中NCAM mRNA和蛋白水平的动态变化过程。结果显示,强直刺激诱发fEPSP斜率升高10 min时,海马CA1区NCAM mRNA染色阳性神经元数量显著增加(76.6±11.5个),NCAM蛋白水平亦明显升高(7.190±0.64任意单位/50μg蛋白)。强直刺激诱发fEPSP斜率升高1 h时,NCAM mRNA染色阳性神经元数量为73.3±14.0个,NCAM蛋白量为9.031±0.71任意单位/50 μg蛋白;与强直刺激后10 min比较,NCAM mRNA表达无显著变化,而NCAM蛋白水平变化明显。NMDA受体特异阻断剂AP-5在损害LTP的同时,显著抑制NCAM mRNA和蛋白的增加。实验结果表明,在大鼠海马LTP诱导和维持过程中,NCAM mRNA增强的表达相对稳定,而NCAM蛋白水平呈现先低后高的变化。  相似文献   

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AMPA receptor-mediated neurotoxicity is currently the most plausible hypothesis for the etiology of amyotrophic lateral sclerosis (ALS). The mechanism initiating this type of neuronal death is believed to be exaggerated Ca2+-influx through AMPA receptors, which is critically determined by the presence or absence of the glutamate receptor subunit 2 (GluR2) in the assembly. We have provided the first quantitative measurements of the expression profile of AMPA receptor subunits mRNAs in human single neurons by means of quantitative RT-PCR with a laser microdissector. Among the AMPA subunits, GluR2 shared the vast majority throughout the neuronal subsets and tissues examined. Furthermore, both the expression level and the proportion of GluR2 mRNA in motoneurons were the lowest among all neuronal subsets examined, whereas those in motoneurons of ALS did not differ from the control group, implying that selective reduction of the GluR2 subunit cannot be a mechanism of AMPA receptor-mediated neurotoxicity in ALS. However, the low relative abundance of GluR2 might provide spinal motoneurons with conditions that are easily affected by changes of AMPA receptor properties including deficient GluR2 mRNA editing in ALS.  相似文献   

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Reduction in GluR2 subunit expression and subsequent increases in AMPA receptor mediated Ca(2+) currents were postulated to exacerbate glutamate neurotoxicity following seizures or global ischemia. To directly test the effects of shifting the GluR1/GluR2 subunit ratio on excitotoxicity, GluR2 antisense deoxyoligonucleotides (AS-ODNs) were applied to dissociated hippocampal cultures for 1-8 days. The GluR1/GluR2 protein ratio was examined immunohistochemically and by Western blotting. [Ca(2+)](i) concentrations were determined by ratiometric imaging of Fura 2-loaded cells. The cultures were exposed to glutamate, AMPA, NMDA or kainic acid (KA) 3 days after GluR2 knockdown and cell viability was determined 1 day later by MTT reduction assay or Trypan blue exclusion. Although GluR2 AS-ODNs increased the GluR1/GluR2 protein ratio in a time dependent manner, neurons and glia appeared healthy and MTT reduction values were similar to untreated and sense controls. Basal [Ca(2+)](i) levels were unchanged but [Ca(2+)](i) was selectively increased by agonist stimulation of AMPA receptors. Unexpectedly, delayed neurotoxicity was attenuated at saturating doses of glutamate while little difference in cell viability was observed at lower doses or with the other excitotoxins at any concentration. Therefore, there was a dissociation between rises in AMPA receptor-mediated Ca(2+) influx and neurotoxicity despite marked decreases in GluR2 but not GluR1 immunoreactivity. It is proposed that a modification of AMPA receptor stochiometry that raises agonist-stimulated Ca(2+) influx during an excitotoxic insult may have eventual neuroprotective effects.  相似文献   

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Abstract : The expression of glutamate receptor/subunit mRNAs was examined 3 weeks after discontinuing 1 week of daily injections of saline or cocaine. The level of mRNA for GluR1-4, NMDAR1, and mGluR5 receptors was measured with in situ hybridization and RT-PCR. In nucleus accumbens, acute cocaine treatment significantly reduced the mRNA level for GluR3, GluR4, and NMDAR1 subunits, whereas repeated cocaine reduced the level for GluR3 mRNA. Acute cocaine treatment also reduced the NMDAR1 mRNA level in dorsolateral striatum and ventral tegmental area. In prefrontal cortex, repeated cocaine treatment significantly increased the level of GluR2 mRNA. The GluR2 mRNA level was not changed by acute or repeated cocaine in any other brain regions examined. Repeated cocaine treatment also significantly increased mGluR5 mRNA levels in nucleus accumbens shell and dorsolateral striatum. Functional properties of the ionotropic glutamate receptors are determined by subunit composition. In addition, metabotropic glutamate receptors can modulate synaptic transmission and the response to stimulation of ionotropic receptors. Thus, the observed changes in levels of AMPA and NMDA receptor subunits and the mGluR5 metabotropic receptor may alter excitatory neurotransmission in the mesocorticolimbic dopamine system, which could play a significant role in the enduring biochemical and behavioral effects of cocaine.  相似文献   

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Unilateral hypoglossal nerve axotomy was used as a model to analyse immunohistochemically the expression of the GluR1, GluR2, GluR3, and GluR4 glutamate receptor subunits of the α-amino-3-hydroxy-5-methyl-4-isoxazolepropionate (AMPA) subtype and the NR1 subunit of the N-methyl-D-aspartate (NMDA) subtype in the different morphofunctional hypoglossal pools from 1 to 45 days postaxotomy. Following hypoglossal nerve axotomy, the percentage of motoneurons that were GluR1-immunopositive and the labeling intensity for this subunit was increased in some hypoglossal pools. Immunolabeling for the GluR2 subunit was undetectable. These results contrast with the unchanged pattern for these two subunits after sciatic nerve axotomy previously described. Image analysis showed a significant decrease in the intensity of immunohistochemical labeling for the GluR2/3 and GluR4 subunits in motoneurons, although most motoneurons were still immunopositive for these 2 subunits after axotomy. The intensity of immunolabeling for the NR1 subunit was slightly decreased postlesion, whereas the percentage of NR1-immunopositive motoneurons increased. Immunoreactivity returned to basal levels 45 days postlesion. These findings show that in axotomized hypoglossal motoneurons, i) AMPA and NMDA receptor subunits are still expressed, ii) the composition of the ionotropic glutamate receptor subunit pool is subjected to continuous changes during the regeneration process, iii) AMPA receptors, if functional, would have physiological properties different to those in intact motoneurons, and iv) the various AMPA receptor subunits are differentially regulated. The present results also suggest a faster recovery of basal levels of immunoreactivity for caudally localised groups of motoneurons which could reflect a caudo-rostral sequential functional revovery in the hypoglossal nucleus.  相似文献   

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