Effects of scopolamine on expression of p-CREB and c-Fos in amygdala nucleus in rats with recurrence of conditioned place preference induced by morphine

AIM :To dectect the effects of scopolamine on expression of phospho-cAMP response element binding protein(p-CREB)and c-Fos in amygdala nucleus(Amy)in rats with recurrence of conditioned place preference(CPP)induced by morphine.METHODS :Morphine was administered by subcutaneous injection at gradually increasing dose(from 10 mg/kg to 60 mg/kg)for 6 days to establish CPP model.From d 7,the rats were administered saline instead of morphine for 10 days to induce CPP extinction.The rats were given a single priming injection of morphine(4 mg/kg)to reinstate the CPP model,some rats were treated by i.p.scopolamine(1,2,3 mg/kg)prior to priminging injection of morphine.The expression of p-CREB and c-Fos in Amy were assayed by immunohistochemistry in the phase of reoccurrence of CPP.RESULTS :After priming injection of morphine 4 mg/kg,the time spent on the drug paired side was significantly reduced because of the treatment with scopolamine,compared with that in the morphine group(P 0.05).Compared with the morphine group,scopolamine decreased the expression of p-CREB and c-Fos of Amy in rats(P 0.05).CONCLUSION :The effects of scopolamine inhibiting morphine CPP reccurrence were probably related to its inhibitory effect on p-CREB and c-Fos expression of Amy in rat.