褪黑素对癫痫大鼠海马GABA、GABAARα5表达的影响

目的 探讨褪黑素(Mel)抗癫痫作用的机制.方法 采用匹罗卡品(PILO)诱导大鼠癫痫持续状态(SE)模型,用免疫组化技术检测大鼠SE后4个时相点即6 h、48 h、72 h和7 d海马γ-氨基丁酸(GABA)和GABAA受体α5(GABAARα5)亚单位表达的动态变化,以及Mel对其变化的影响.结果 PILO组大鼠SE后6h,海马内GABA能神经元和GABAARα5亚单位表达均开始减少,尤其以SE后72 h～7 d改变最为明显,与对照组比较差异有极显著意义(P＜0.01);而Mel组大鼠在SE后72 h～7 d,海马各区的GABA能神经元和GABAARα5亚单位表达均显著高于PILO组大鼠(P＜0.05).结论 Mel可能通过上调GABA和GABAARα5亚单位的表达来发挥抗癫痫作用.

Effect of melatonin on expression of GABA and GABAA receptor α5 subunit in hippocampus of rats after pilocarpine-induced status epilepticus

Objective To probe into the mechanism of anticonvulsant by melatonin (Mel).Methods The rat models of status epilepticus(SE)were induced by pilocarpine(PILO).Changes of expression of γ-Aminobutyric acid(GABA)and GABAA receptor α5 subunit in the hippocampus of SE rats and the effect of Mel on these changes were observed by immunocytochemistry at post-SE 6,48,72 h,7 d. Results The expression of GABA and GABAA receptor α5 subunit began to decrease in PILO group at post-SE 6 h. The expression of GABA and GABAA receptor α5 subunit was significantly lower in PILO group than in control group at post-SE 72 h-7 d(P＜0.01). But the expression of GABA and GABAA receptor α5 subunit was significantly higher in Mel group than in PILO group at post-SE 72 h-7 d (P＜0.05). Conclusions Anticonvulsive effect of Mel may be due to its ability to increase the expression of GABA and GABAA receptor α5 subunit.