慢性吗啡处理及戒断后大鼠前额皮质、海马和杏仁核中Parvalbumin的表达变化

为了观察慢性吗啡处理及戒断后大鼠前额皮质、海马和杏仁核中parvalbumin(PV)的表达变化,为其功能的研究提供形态学依据,本实验将30只雄性SD大鼠随机分为吗啡依赖组和生理盐水对照组。吗啡依赖组大鼠腹膜腔注射吗啡,2次/d,起始剂量为5mg/kg,逐日递增5mg,至第10d为50mg/kg;对照组注射同体积的生理盐水。于末次注射后动物分别存活3h、3d和14d。用免疫组化方法和相对平均灰度值检测前额皮质、海马和杏仁核内PV的表达。结果显示:在生理盐水处理组各存活时间点,前额皮质、海马和杏仁核内PV的表达相同。和生理盐水对照组相比,3h时海马和杏仁核内PV的表达明显增加(P<0.05),但前额皮质内PV的表达减少。第3d时,海马CA1、CA3、CA4、齿状回和杏仁核内PV的表达减少,但CA2区PV表达继续增加,而前额皮质的表达开始恢复。至第14d时,CA2区PV的表达开始恢复,但CA1、CA4和杏仁核内PV的表达又开始增加,明显高于第3d组(P<0.05)。以上结果提示慢性吗啡处理及戒断后PV的表达具有区域特异性和时相特异性;这种变化在戒断早期可能主要与躯体依赖相关,而戒断晚期主要与精神依赖相关。

THE CHANGES OF PARVALBUMIN EXPRESSION IN THE RAT PREFRONTAL CORTEX, HIPPOCAMPUS AND AMYGDALA AFTER CHRONIC MORPHINE TREATMENT AND WITHDRAWAL

In order to observe the changes of parvalbumin(PV)expression in the rat prefrontal cortex,hippocampus and amygdala after chronic morphine treatment and withdrawal,and provide the morphologic evidence for its functional research.In the present study,thirty 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 groups were killed 3 hours,3 days or 14 days after the last injection.The PV expression in the rat prefrontal cortex,hippocampus and amygdala was observed by immunohistochemistry and the mean of relative gray scale.The results showed that the PV expression in the rat prefrontal cortex,hippocampus and amygdala was same among the survival time points in the saline treated group.Compared to the saline treated group,the PV expression in the hippocampus and amygdala was significantly increased at 3 h after the last injection of morphine(P<0.05),but PV expression in the prefrontal cortex was reduced.On the 3rd day after the last injection of morphine,PV expression in the hippocampal CA1,CA3,CA4,dentates gyrus and amygdala was decreased.On contrast,PV expression in the hippocampal CA2 continued to increase and that in prefrontal cortex began to restore.To the 14th day,PV expression in the CA2 began to restore.Yet the PV expression in the CA1,CA4 and amygdala began to increase again,and significantly higher than that on the 3rd day(P<0.05).The above results suggest that the PV expression after chronic morphine treatment and withdrawal is region-specific and time-specific,which is possibly relative to the physical dependence at the early stage of withdrawal and to psychological dependence at later stage.