Effect of melatonin on GAD67 mRNA expression in post-SE rat hippocampus induced by pilocarpine

Objective To probe the mechanism of anticonvulsant by melatonin from the angle of neurotransmitter.Methods Rat status epilepticus(SE) model was induced by pilocarpine(PILO).γ-aminobutyric acid(GABA) content and glutamin acid decarboxylase(GAD)67 mRNA expression was detected at 6,48,72 h,and 7 d in the hippocampus of post-SE rats.The effect of melatonin on these changes was observed.Results GABA content was significantly lower in the hippocampus than in control(P0.01).At 6-72 h post-SE,the expression of GAD67 mRNA was significantly lower in PILO group than in control(P0.01),but significantly higher in PILO group than in control at 7 d post-SE.The content of GABA was significantly higher in PILO+Mel group than in PILO group at 6 h-7 d post-SE(P0.01)and the expression of GAD67 mRNA was significantly higher in PILO+Mel group than in PILO group at 6-72 h post-SE(P0.05).Conclusion Anticonvulsive effect of melatonin may be due to its ability to increase the expression of GAD67 mRNA,so to increase the content of GABA.