遗传性癫病易感大鼠惊厥后脑内N-甲基-D-天冬氨酸受体亚基NR1、NR2A、NR2B蛋白的表达

目的:探讨惊厥后大脑皮质N-甲基-D天冬氨酸(N-methyl-Daspartate,NMDA)受体亚基蛋白表达与癫癎发病机制的关系.方法:利用免疫组化技术,观察听源性癫癎易感大鼠P77PMC惊厥后不同时间大脑皮质、海马等脑区NMDA受体亚基NR1,NR2A,NR2B蛋白表达状况.结果:惊厥后大脑皮质,海马齿状回,CA1、CA3等脑区NR1蛋白表达呈时间依赖性增高.大脑皮质在惊厥后4 h NR1蛋白表达即开始增加,24～48 h达高峰,海马齿状回、CA1和CA3等脑区4 h达高峰,8 h开始下降,24 h后恢复正常.惊厥后4～8 h,在海马CA1区NR2A亚基蛋白表达短暂性降低.而在大脑皮质、海马齿状回和CA3等脑区,惊厥后各时间点NR2A,NR2B蛋白表达均无明显改变.结论:听源性惊厥后NMDA受体亚基蛋白表达的变化提示NMDA受体亚基组成的改变,这种改变可能与神经网络兴奋性增高及癫癎易感性的保持有关.

Audiogenic seizure can alter N-methyl-D-aspartate receptor subunits NR1, NR2A, NR2B immunoreactivity in epilepsy-prone rat brain

Objective: To determine the role of N methyl D aspartate receptor subunits in the pathogenisis of epilepsy. Methods: Immunohistochemistry was used to detect the protein expression of NMDA receptor subunits NR1, NR2A and NR2B in cortex and hippocampus of genetically epilepsy prone rat (P77PMC) after audiogenic seizure. Results: The NR1 subunit immunoreactivity increased time dependently and reached a peak at hour 24 to 48 in cortex, and at hour 4 in hippocampus respectively after audiogenic seizure and the immunoreactivity of NR2A subunit reduced transiently in CA1 of hippocampus, being maximal 4 8 hours after seizure. In cortex, CA3 and dentate gyrus the immuno staining remained unaltered. No alteration of NR2B was observed at the same time. Conclusion: Those changes may contribute to an altered excitability of neuronal network, and also suggest the alteration of NMDA receptor subunits constitusion after audiogenic seizure in P77PMC rat.