慢性复合应激性增强空间学习与记忆时突触素Ⅰ在大鼠海马中的表达

EXPRESSION OF SYNAPSIN Ⅰ IN THE HIPPOCAMPUS OF THE RAT AS THEIR SPATIAL LEARNING AND MEMORY WERE ENHANCED BY CHRONIC MULTIPLE STRESS

目的 观察突触素Ⅰ在慢性复合应激性空间学习与记忆增强大鼠海马各亚区表达的变化及其意义。方法 成年雄性Wistar大鼠随机分成应激组和对照组。采用垂直旋转、剥夺睡眠、噪音刺激和夜间光照 4种应激原无规律交替应激动物 6周 ,每天 6h ,制作慢性复合应激动物模型。采用Morris水迷宫和Y 迷宫测试大鼠空间学习与记忆成绩 ,并用免疫组织化学技术显示突触素Ⅰ在慢性复合应激性空间学习与记忆增强大鼠海马中的表达变化。结果 结果显示 ,应激组动物慢性复合应激后在Morris水迷宫内寻找隐蔽平台所需时间 (潜伏期 )比对照组的明显地短 (P <0 0 5 ) ,在Y 迷宫内寻找安全区的正确率比对照组的明显地高 (P <0 0 5 ) ;应激组动物慢性复合应激后 ,其海马齿状回 (dentategyrus ,DG)和CA3区突触素I的免疫反应性明显地强于对照组 (P <0 0 5 ) ,两组CA1区突触素I的免疫反应性无明显差别 (P >0 0 5 )。结论 这些结果提示 ,慢性复合应激可增强大鼠空间学习与记忆能力 ,突触素Ⅰ在大鼠海马内表达的变化可能参与了大鼠空间学习与记忆增强的机制。

Objective To investigate the expression and significance of synapsin Ⅰin different subfields of the hippocampus of rats whose spatial learning and memoryfunction were enhanced by chronic multiple stress. Method Adult male Wistar rats were randomly divided into the stressedand the control group. Rats in the stressedgroup were irregularly and alternatively exposed to vertical rotention, sleep expropriation, noise stimulation, and night illumination 6h each day for 6 weeks to estatlish the model of chronic complex stress. Spatial learning and memory performance of the rats was measured by first using Morris water maze and afterwards Y-maze. The expression of synapsin Ⅰ in different subfields of the hippocampus of the rats was observed by using immunohistochemical method.Result (1) After the chronic complex stress, compared with that of the control group, the latent period to search the platform in Morris water maze was significantly shortened in the stressed rats (P<0.05);in the test of Y-maze, the correct rate of avoidingthe electric shock was remarkably increased in the stressedrats (P<0.01).(2) After the chronic complexstress, the immunoreactivity of synapsin I in DG and hippocampalarea CA3 weresignificantly strongerthan those of the control group (P<0.05).But no difference was observed in the expression of synapsin Iin CA1. Conclusion These results suggest that the chronic multiplestress may enhance the spatial learning and memory functionof the ratand that the changes of synapsin I expression in the rat hippocampus may participate in the mechanism of enhanced learning and memory.