褪黑素对癫痫大鼠海马GABA、GABAARα5表达的影响

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

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6h、48h、72h和7d海马γ-氨基丁酸（GABA）和GABA。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72h～7d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72h-7d，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。

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 ct5 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.