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

Abstract

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. Key words: Status epilepticus; Hippocampus; Pilocarpine; Melatonin; γ-Aminobutyric acid