Expression of calbindin in CA1 area of hippocam pus in rats after chronic morphine treatment and withdrawal.

Objective:To investigate the expression of calbindin(CB) in the rat CA1 area of hippocampus after chronic morphine treatment and withdrawal,and provide the morphologic evidence for its functional research.Method:Thirty-six SD male rats were randomly divided into morphine treated and saline control groups.The rats in morphine treated group were intraperitoneally injected with morphine twice a day for 10 days.The initial dose of injected morphine was 5 mg/kg,then the dose was added as 5 mg/kg day by day.To 10th day,the dose reached to the 50 mg/kg.The rats in saline treated group were injected with same volume of saline.Rats in both group swere killed 3 hours,3 days or 14 days after the last injection.The CB expression in the rat CA1 area of hippocampus was detected by immunohistochemistry and the mean of relative gray scale.Result:The results showed that the CB expression in the rat CA1 area of hippocampus was same among the survival time points in the saline treated group.Compared to the saline treated group,the CB expression in CA1 area of hippocampus was significantly increased at 3 h,3d after the last injection of morphine(P0.05),then restored at 14d.Conclusion:The increase expression of CB in CA1 area of hippocampus may have a protective role after chronic morphine treatment and withdrawal.