GAD67/GAD65在颞叶癫痫大鼠海马内源性促痫机制中的作用

目的探讨GAD67/GAD65在颞叶癫痫发生后大鼠海马内源性促痫机制中的作用.方法112只雄性SD大鼠随机分为实验组(n=70)与对照组(n=42),实验组大鼠选用海人酸腹腔注射法建立颞叶癫痫模型,对照组大鼠腹腔注射无菌生理盐水.选取腹腔注射后3 h、6 h、12 h、24 h、48 h、7 d、30 d为研究的时间点,颞叶海马的CA1区、CA3区、齿状回为研究部位.腹腔给药后每天观察大鼠的行为学变化,大鼠处死前进行EEG描记.免疫组织化学法检测GAD65、GAD67蛋白的表达.结果海人酸致痫后6 h,实验组大鼠海马CA1区、CA3区GAD67/GAD65的比率较对照组升高(P＜0.01);海人酸致痫后30 d,实验组大鼠海马齿状回GAD67/GAD65的比率较对照组降低(P＜0.05).结论颞叶癫痫急性期CA1区、CA3区GAD67/GAD65比率的增高及慢性期齿状回GAD67/GAD65比率的降低与颞叶癫痫发生及癫痫发生后机体的内源性抗痫机制密切相关.     

癫痫状态大鼠海马HSP70mRNA及GAD67mRNA表达水平的研究

目的 研究癫痫演变过程中特定脑区选择性神经元损伤与修复机制。方法 采用分子杂交方法动态观察了马桑内酯（coriaria Lactone,CL)诱导的癫痫状态大鼠海马区早期神经元损伤标志物热休克蛋白（heat shock protein,HSP)70mRNA及谷氨酸脱羧酶（glutamin acid decarboxylase,GAD)67mRNA表达水平的变化,同时也观察了大鼠行为学及脑电图改变。结果 侧脑室注射CL后20分钟,大鼠出现连续发作的四肢抽搐伴有EEG持续性的棘慢波及尖波发放。注射CL后2小时组大鼠海马GAD67 mRNA表达水平有所降低,但HSP70mRNA变化不明显,注射CL后8小时组大鼠海马GAD67mRNA表达水平有所降低,但HSP70mRNA表达变化不明显,注射CL后8小时组大鼠海马GAD67mRNA表达水平明显低于对照组（P＜0．01）,HSP70mRNA表达水平较对照组明显增高（P＜0．01）。结论 癫痫状态期间大鼠海马区可能存在神经元损伤与修复过程,而且GABA能神经元受到不同程度的损伤。     

癫痫状态大鼠海马HSP70 mRNA及GAD67 mRNA表达水平的研究

目的研究癫痫演变过程中特定脑区选择性神经元损伤与修复机制。方法采用分子杂交方法动态观察了马桑内酯(coriariaLactone,CL)诱导的癫痫状态大鼠海马区早期神经元损伤标志物热休克蛋白(heatshockprotein,HSP)70mRNA及谷氨酸脱羧酶(glutaminaciddecarboxylase,GAD)67mRNA表达水平的变化,同时也观察了大鼠行为学及脑电图改变。结果侧脑室注射CL后20分钟,大鼠出现连续发作的四肢抽搐伴有EEG持续性的棘慢波及尖波发放。注射CL后2小时组大鼠海马GAD67mRNA表达水平有所降低,但HSP70mRNA表达变化不明显,注射CL后8小时组大鼠海马GAD67mRNA表达水平明显低于对照组(P＜0.01),HSP70mRNA表达水平较对照组明显增高(P＜0.01)。结论癫痫状态期间大鼠海马区可能存在神经元损伤与修复过程,而且GABA能神经元受到不同程度的损伤。     

颞叶癫痫大鼠海马CA1区Sema3C、Np1的表达变化研究

目的探讨颞叶癫痫的发病机制。方法取健康雄性SD大鼠制成颞叶癫痫模型，用免疫组织化学和原位杂交技术对匹罗卡品致痫后不同时间点CA1区的Sema3C mRNA、Np1 mRNA和蛋白表达进行分析。结果在匹罗卡品致痫后7d，实验组CA1区Sema3C、Np1的表达明显低于对照组（P〈0．01）。结论CA1区Sema3C、Np1的表达下凋可能参与了海马CA1区内的轴突出芽机制。     

中枢组胺对戊四氮点燃大鼠海马GABA能神经元的影响

目的:探讨中枢组胺抗癫痫的作用机制。方法:应用免疫组织化学方法研究中枢组胺对戊四氮(PTZ)致癫痫大鼠海马神经元GABA、GAD67表达的影响。结果:戊四氮致痫组大鼠海马神经元GABA、GAD67的表达量明显低于正常对照组,L-组胺酸干预组明显高于戊四氮致痫组,L-组胺酸干预组与正常对照组之间差异无显著性意义。结论:中枢组胺通过激活海马GABA能神经元来抑制癫痫的发生和发展。     

电压门控性钠通道mRNA在海人酸致痫大鼠表达的研究

目的:探讨电压门控性钠通道在癫痫发病机制中的作用。方法:采用海人酸颞叶癫痫模型,运用原位杂交技术检测不同时点海马DG区、CA1区、CA2区和CA3区SCN2A、SCN3A mRNA的表达。结果:SCN2A和SCN3AmRNA均表达于海马的DG区、CA1、CA2、CA3区。海人酸致痫后3小时在海马各区表达开始增强,6小时明显增强(P<0.05),12小时达到高峰(P<0.01),24小时开始下降,48小时恢复至正常水平。结论:电压门控性钠通道SCN2AmRNA和SCN3A mRNA的表达增加可能参与了颞叶癫痫急性期的发病。     

电针对癫痫模型大鼠自发性反复发作及海马CA3和DG区谷氨酸脱羧酶67表达的影响

背景由于对药物疗法不良反应的担忧,近几年人们对使用针灸治疗癫痫越来越感兴趣。尽管现已报道了不少针灸抗癫痫作用的临床证据,但其确切机制仍不清楚。目的 研究电针(EA)对癫痫大鼠自发性复发性癫痫(SRS),以及海马CA3和齿状回(DG)区中谷氨酸脱羧酶67(GAD67)表达的影响。方法 将50只Sprague-Dawley(SD)大鼠随机分为对照组、癫痫组、假刺激组、非穴位电针组和穴位电针组,每组10只。除对照组外,其余4组均制备氯化锂—匹罗卡品颞叶癫痫大鼠模型。造模成功的大鼠采用针刺或电针穴位治疗,8周后观察自发性复发性癫痫发作的次数。分别取5组大鼠海马组织,采用荧光定量PCR和Western blotting分别检测各组大鼠海马组织中GAD67 mRNA水平和蛋白水平表达变化;采用免疫组化法检测各组大鼠海马CA3和DG区GAD67蛋白水平表达变化。结果 治疗8周后,穴位电针组与癫痫组、假刺激组、非穴位电针组比较,减少了自发性复发性癫痫发作的次数,差异有统计学意义(P<0.05)。qRT-PCR结果显示：与对照组相比,癫痫组、假刺激组、非穴位电针组和穴位电针组大鼠海马组织中GAD6...     

颞叶癫痫大鼠海马TrkB mRNA及其蛋白表达的动态变化

目的 探讨颞叶癫痫发作大鼠海马TrkB mRNA及其蛋白表达的动态变化特征。方法 建立匹罗卡品(PILO)颞叶癫痢大鼠模型,应用原位杂交及免疫组织化学方法分别检测致(?)大鼠海马齿状回、CA3区及CA1区TrkB nRNA及其蛋白质表达的变化。结果 PILO致(?)后3～6 h,海马齿状回颗粒细胞层、CA1、CA3区锥体细胞层TrkB mRNA表达显著增高(P<0.01),稍后TrkB蛋白表达也随之增高。第7-30 d,TrkB mRNA及其蛋白在齿状回、CA3区呈现第二次表达增强。结论在癫(?)发作早期,TrkB表达增强,提示其可能参与急性癫痫状态的发生;后期表达增强则可能参与了海马的可塑性反应而与慢性自发性发作形成有关。     

青霉素致痫大鼠脑内HSP70的表达

目的 探讨应激蛋白HSP70在癫痫大鼠脑组织中的表迭及其意义。方法 采用腹腔注射青霉素法复制大鼠癫痫模型，免疫组织化学方法检测大脑皮层、海马组织中HSP70表迭的变化。结果 (1)实验组大鼠给药后均有程度不同的癫痫行为发生；(2)对照组大鼠脑内未见HSP70阳性细胞，青霉素致痈后大鼠大脑皮层、海马出现HSP70阳性细胞。在海马的CA1、CA3、CA4区和颞叶皮质HSP70阳性细胞较为密集。结论 青霉素致痫大鼠脑内可见HSP70的广泛表达，提示HSP70蛋白在癫痫发生过程中可能对神经元具有保护作用。     

杏仁核点燃癫痫鼠GAD67mRNA的表达

目的 探讨大鼠杏仁核点燃癫痫后脑组织谷氨酸脱羧酶（GAD）mRNA的表达及其在癫痫发作后表达变化的意义。方法 通过建立与人类癫痫发生,形成具有高度相似性的杏仁核点燃大鼠癫痫模型。采用原位杂交技术检测癫痫鼠颞叶及海马组织不同点燃时程GAD67mRNA表达。结果 点燃后1d,GAD67mRNA表达增多并且表达信号增强,至7d时达高峰,以后表达逐渐下降,但在点燃后49d,表达仍高于正常,与对照组及手术对照组相比有统计学差异。结论 在慢性癫痫发作中,GABA能神经元的活性增强,考虑是由于癫痫过程中兴奋性增强,引起GABA能神经元抑制功能代偿性增加的结果,即癫痫发作后GABA能神经元介入的抑制功能代偿性增加的,这可能是机体内源性抗癫痫机制增强的一种反应。     

葛根素对实验性脑缺血GAD67mRNA表达变化的影响

目的观察葛根素对实验性脑缺血谷氨酸脱羧酶(GAD67)表达变化的影响。方法应用原位杂交方法检测大鼠永久大脑中动脉闭塞(MCAO)模型GAD67mRNA在脑缺血后不同时间的表达。结果正常组及假手术组GAD67mRNA在脑组织中表达较弱。对照组和治疗组GAD67mRNA在脑缺血后6h即开始表达增强,在72h 达高峰,后逐渐下降,GAD67mRNA表达至第2周仍高于正常,治疗组GAD67mRNA表达高于对照组。结论葛根素可以促进实验性脑缺血后GAD67mRNA的表达,具有神经保护作用,有助于神经功能的恢复。     

Up-regulation of GAD65 and GAD67 in remaining hippocampal GABA neurons in a model of temporal lobe epilepsy.

In the pilocarpine model of chronic limbic seizures, subpopulations of glutamic acid decarboxylase (GAD)-containing neurons within the hilus of the dentate gyrus and stratum oriens of the CA1 hippocampal region are vulnerable to seizure-induced damage. However, many gamma-aminobutyric acid (GABA) neurons remain in these and other regions of the hippocampal formation. To determine whether long-term changes occur in the main metabolic pathway responsible for GABA synthesis in remaining GABA neurons, the levels of mRNA and protein labeling for the two forms of GAD (GAD65 and GAD67) were studied in pilocarpine-treated animals that had developed spontaneous seizures. Qualitative and semiquantitative analyses of nonradioactive in situ hybridization experiments demonstrated marked increases in the relative amounts of GAD65 and GAD67 mRNAs in remaining hippocampal GABA neurons. In addition, immunohistochemical studies demonstrated parallel increases in the intensity of terminal labeling for both GAD65 and GAD67 isoforms throughout the hippocampal formation. These increases were most striking for GAD65, the isoform of GAD that is particularly abundant in axon terminals. These findings demonstrate that, in a neuronal network that is capable of generating seizures, both GAD65 and GAD67 are up-regulated at the gene and protein levels in the remaining GABA neurons of the hippocampal formation. This study provides further evidence for the complexity of changes in the GABA system in this model of temporal lobe epilepsy.     

戊四氮所致慢性癫痫发病过程中谷氨酸脱羧酶基因表达的研究

目的：观察谷氨酸脱羧酶（GAD）67mRNA表达在慢性癫痫演变过程的变化,并探讨其作用。方法：采用寡核苷酸探针原位组织杂交技术检测慢性癫痫演变过程中各期皮层,海马GAD67mRNA的表达水平。结果：慢性癫痫演变过程中GAD67mRNA阳性细胞数略有减少,但与对照组比较无显著性差异。而继续存活的GAD67mRNA阳性细胞平均吸光度明显增加,与对照组比较有显著性差异（P＜0．01）,结论：继续存活的GAD67m RNA阳性细胞GAD67mRNA表达水平的增高可能是机体的一种内源性抗病表现。     

Glutamate decarboxylase 67 is expressed in hippocampal mossy fibers of temporal lobe epilepsy patients

Recently, expression of glutamate decarboxylase-67 (GAD67), a key enzyme of GABA synthesis, was detected in the otherwise glutamatergic mossy fibers of the rat hippocampus. Synthesis of the enzyme was markedly enhanced after experimentally induced status epilepticus. Here, we investigated the expression of GAD67 protein and mRNA in 44 hippocampal specimens from patients with mesial temporal lobe epilepsy (TLE) using double immunofluorescence histochemistry, immunoblotting, and in situ hybridization. Both in specimens with (n = 37) and without (n = 7) hippocampal sclerosis, GAD67 was highly coexpressed with dynorphin in terminal areas of mossy fibers, including the dentate hilus and the stratum lucidum of sector CA3. In the cases with Ammon's horn sclerosis, also the inner molecular layer of the dentate gyrus contained strong staining for GAD67 immunoreactivity, indicating labeling of mossy fiber terminals that specifically sprout into this area. Double immunofluorescence revealed the colocalization of GAD67 immunoreactivity with the mossy fiber marker dynorphin. The extent of colabeling correlated with the number of seizures experienced by the patients. Furthermore, GAD67 mRNA was found in granule cells of the dentate gyrus. Levels, both of GAD67 mRNA and of GAD67 immunoreactivity were similar in sclerotic and nonsclerotic specimens and appeared to be increased compared to post mortem controls. Provided that the strong expression of GAD67 results in synthesis of GABA in hippocampal mossy fibers this may represent a self-protecting mechanism in TLE. In addition GAD67 expression also may result in conversion of excessive intracellular glutamate to nontoxic GABA within mossy fiber terminals.     

Expression of plasma membrane GABA transporters but not of the vesicular GABA transporter in dentate granule cells after kainic acid seizures

Kainic acid-induced seizures cause a marked increase in the expression of glutamate decarboxylase 67 (GAD67) in granule cells of the dentate gyrus. To determine the possible modes of sequestration of newly formed gamma-aminobutyric acid (GABA), we used in situ hybridization and immunocytochemistry to investigate the expression of several proteins related to GABA in dentate granule cells of rats 4 h to 60 days after kainic acid-induced status epilepticus and in controls. GAD67 and GAD65 mRNA levels were increased by up to 300% and 800%, respectively, in the granule cell layer 6-24 h after kainate injection. Subsequently, increased GAD and GABA immunoreactivity was observed in the terminal field of mossy fibers and in presumed dendrites of granule cells. mRNA of both known plasma membrane GABA transporters (GAT-1 and GAT-3) was expressed in granule cells of control rats. GAT-1 mRNA levels increased (by 30%) 9 h after kainate injection but were reduced by about 25% at later intervals. GAT-3 mRNA was reduced (by 35-75%) in granule cells 4 h to 30 days after kainic acid injection. In contrast, no expression of the mRNA or immunoreactivity of the vesicular GABA transporter was detected in granule cells or in mossy fibers, respectively. GABA transaminase mRNA was only faintly expressed in granule cells, and its levels were reduced (by 60-65%) 12 h to 30 days after kainate treatment. The results indicate that GABA can be taken up and synthesized in granule cells. No evidence for the expression of the vesicular GABA transporter (VGAT) in granule cells was obtained. After sustained epileptic seizures, the markedly increased expression of glutamate decarboxylase and the reduced expression of GABA transaminase may result in increased cytoplasmic GABA concentrations in granule cells. It is suggested that, during epileptic seizures, elevated intracellular GABA and sodium concentration could then result in nonvesicular release of GABA from granule cell dendrites. GABA could then act on GABA-A receptors, protecting granule cells from overexcitation.     

Localization of cells preferentially expressing GAD(67) with negligible GAD(65) transcripts in the rat hippocampus. A double in situ hybridization study.

Two major forms of glutamic acid decarboxylase (GAD) are present in the mammalian brain, a 65-kDa isoform (GAD(65)) and a 67-kDa isoform (GAD(67)), and it is usually assumed that all GABAergic neurons contain both. The two forms have not yet been colocalized to the same neurons, because the GAD(65) protein is found almost exclusively in axon terminals, while GAD(67) is found predominantly in the cell body. Using double in situ hybridization (DISH) with both radioactive [35S] and non-radioactive (digoxigenin, DIG) probes, the distributions of GAD(65) and GAD(67) mRNA have been simultaneously examined in the rat hippocampus. The results suggest that [35S] radioprobes are slightly more sensitive than DIG probes, and that the reversal of labels is necessary in DISH studies to determine whether a neuronal subtype which expresses only one isoform of GAD may be present. The data indicate that the majority of cells (90%) showing labeling were labeled for both GAD(65) and GAD(67) mRNA. In sectors CA1 and CA3 approximately 5-10% of the cells positive for GAD(67) showed little or no detectable GAD(65) mRNA. In the hilus, however, GAD(65) levels were higher, and all cells seem to express both GAD(65) and GAD(67) mRNA. Taken together, these results support the view that most GABAergic neurons in the hippocampus express both GAD(65) and GAD(67). However, it appears that some interneurons in the CA subfields differ from "classic" GABAergic interneurons by preferentially expressing the 67-kDa isoform of GAD under baseline conditions, with GAD(65) mRNA levels very low or absent.     

全脑缺血-再灌注对海马CA1区GAD65表达的影响及意义

目的探讨全脑缺血-再灌注对成年大鼠海马CA1区GAD65表达的影响及意义。方法成年雄性SD大鼠24只,随机分为3组:假手术组(SH)、缺血-再灌注3d组(IR-3)及缺血-再灌注7d组(IR-7),每组8只。采用四动脉阻断法制作全脑缺血-再灌注模型,应用免疫组织化学方法检测海马CA1区谷氨酸脱羧酶(glutamic acid decarboxylase,GAD)同工酶GAD65的表达变化。结果与假手术组相比,IR-3组GAD65的表达明显增多,IR-7组恢复正常。结论GABA能中间神经元对缺血相对耐受;全脑缺血-再灌注3dGAD65的表达增多可能是一种代偿性的机制,以减轻脑缺血后的高兴奋性。