Characterization of molecular events leading to seizure susceptibility in ethacrynic acid-induced seizure model.

在依他尼酸诱导的癫痫发作模型中导致癫痫发作易感性的分子事件的特征。

基本信息

批准号：
08680850
负责人：
OMORI Kyoko
金额：
$ 1.54万
依托单位：
Kansai Medical University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1996
资助国家：
日本
起止时间：
1996 至 1997
项目状态：
已结题

项目摘要

Neuronal alterations by seizures produce a long-lasting reorganization of susceptible neuronal circuity in the central nervous system, culminating in long-term seizure susceptibility. We previously reported that an intracerebroventricular administration of ethacrynic acid (EA) to mice induced repeated tonic-clonic convulsions. We aimed in this seizure model to demonstrate molecular and cellular events leading to the seizure susceptibility, in relation to the expression of immediate early gene c-fos. Studies on the long-term expression of c-fos mRNA revealed that the expression was increased biphasically, with a transient increase at 60 min (early phase) and a prolonged increase on the 10-14th day (late phase) post-EA administration, most remarkably in dentate gyrus and pyriform cortex. The expression of NGF,a neurotrophic factor supposed to play a role in the reorganization of neural circuity, also showed biphasic increases with a close spatiotemporal correlation with c-fos expression. In addition, immuno-histochemical analysis displayd that the dendrites of parvalbumin (PARV) -positive cells, a subpopulation of GABAergic interneurons, were markedly decreased on the 7th day post-EA seizure and that their cell somata also decreased on 14th day. Furthermore, we examined the development of seizure susceptibity in EA-treated mice on the 14th day. Intraperitoneal injection with subconvulsive dose of kainic acid caused severe (stage 5) seizure in 77% of mice recovered from EA seizure with 70% mortality within 10 min. These findings suggest that the transient EA-induced seizures produce the development of long-term seizure susceptibility via prolonged increase in c-fos expression and subsequent increase in NGF mRNA expression. Also, it was supposed that the loss of PARV-positive cells which precede the late phase increase in c-fos expression play a causal role in the development.

通过癫痫发作的神经元改变产生了中枢神经系统中易感神经元循环的长期重组，最终导致长期癫痫发作的敏感性。我们先前曾报道过，脑室内给小鼠乙丙酸（EA）诱导反复的隆隆性抽搐。我们针对这种癫痫发作模型，以证明与直接早期基因c-fos的表达有关的分子和细胞事件。关于C-FOS mRNA的长期表达的研究表明，表达是双层增加的，在60分钟（早期）的瞬时增加，并且在第10-14天（晚期）后AE给药后长期增加，最明显地在齿状回和毛状皮质中。 NGF的表达是一种神经营养因子，在神经循环的重组中起作用，也显示出双相的增加，并且与C-FOS表达的紧密时空相关性。此外，免疫 - 归化分析表明，白细胞蛋白（PARV） - 阳性细胞的树突是GABA能中间神经元的亚群，在EA癫痫发作的第7天显着降低，其细胞SOMATA在第14天也减少了。此外，我们研究了第14天的EA治疗小鼠癫痫发作的发展。腹膜内注射的腹膜内剂量的海藻酸会在10分钟内从EA癫痫发作中以70％死亡率回收的77％的小鼠严重癫痫发作（第5阶段）癫痫发作。这些发现表明，瞬态EA诱导的癫痫发作会通过长期增加C-FOS表达和随后的NGF mRNA表达增加而产生长期癫痫发作的发展。同样，据认为，在C-FOS表达的晚期增加之前，PARV阳性细胞的丧失在发育中起因果作用。