RESUMO
Objective:To investigate the effects of melatonin(MLT)on hypothalamic-pituitary-adrenal(HPA)axis in posttraumatic stress disorder(PTSD)rats induced by foot shocks.Methods:The rat model of PTSD was prepared by plantar electroshock,and MLT was given by intraperitoneal injection.The behavioral changes of rats were detected by rejection reaction test,the mRNA expression of corticotropin-releasing hormone(CRH)in hypothalamus was detected by real time RT-PCR,and the contents of adrenocorticotropin hormone(ACTH),epinephrine(EPI)and glucocorticoid(GC)in serum were detected by enzyme-linked immunosorbent assay(ELISA).Results:In the PTSD group,the rejection reaction was obvious,the expression of CRH mRNA in hypothalamus was increased(P＜0.05),the serum ACTH and EPI were increased(P＜0.05),but the GC level was decreased(P＜0.05).After MLT treatment,the rejection reaction of PTSD rats was significantly alleviated,CRH mRNA expression in hypothalamus was decreased(P＜0.05),serum ACTH and EPI levels were decreased(P＜0.05),and GC levels were increased(P＜0.05).Conclusion:MLT treatment can relieve the symptoms of PTSD and restore the neuroendocrine balance of HPA axis in rats.