条件性恐惧消退保持早期边缘下区细胞周期素依赖性蛋白激酶5的动态变化  

Change of cyclin-dependent kinase 5 in infra-limbic cortex in the early of conditioned fear extinction retention

作　　者：李培培[1] 李敏[1] 张丽丽[1] 韦美[1] 汪涛[1] 

机构地区：[1]第三军医大学护理系心理学教研室,重庆400038

出　　处：《中华行为医学与脑科学杂志》2010年第3期228-230,共3页Chinese Journal of Behavioral Medicine and Brain Science

基　　金：国家自然科学基金资助项目（30670712）;重庆市自然科学基金资助项目（CSTC2009BB5014）

摘　　要：目的研究内侧前额叶皮层边缘下区（IL区）细胞周期素依赖性蛋白激酶5（Cdk5）在条件性恐惧消退保持早期的动态变化。方法成年雄性sD大鼠56只，随机分为消退组（n=24）、假消退组（n＝24）和正常组（n=8）。采用声音结合足底电击建立大鼠条件性恐惧模型，消退组在恐惧建模后24h进行消退训练，假消退组则不进行消退训练，2组均在不同时间点（恐惧建模后第2、4和8天）测定消退保持成绩，并用免疫组织化学法检测各组大鼠内侧前额叶皮层IL区Cdk5的表达。结果（1）与正常组相比，消退组和假消退组在恐惧建立后第2天和第4天的不僵立时间百分比显著较少（P〈0．01），而在恐惧建立后第8天，消退组的保持成绩明显好于假消退组[分别为（71．04±11．65）％和（35．48±12．37）％，P〈0．01]，与正常组无显著差异；（2）在恐惧建立后第2天，消退组大鼠IL区Cdk5免疫阳性细胞数与正常组无差异，假消退组大鼠则明显多于正常组[均值分别为（429±70）个和（322±52）个，P〈0．05]；在恐惧建立后第4天，消退组大鼠的Cdk5阳性细胞数明显减少[为（208±30）个，P〈0．01]，而假消退组基本恢复正常；在恐惧建立后第8天，2组与正常组比较，Cdk5阳性细胞数差异无显著性。结论条件性恐惧训练可能引起IL区Cdk5的水平升高；而消退训练则可能促使Cdk5的表达降低，有利于消退记忆的早期保持。Objective To observe the change of cyclin-dependent kinase 5 （ Cdk5 ） in infra-limbic cortex in the early of conditioned fear extinction retention. Methods Fifty-six male adult SD rats were randomly divided into extinction group, sham extinction group and naive group. Conditioned fear model of rats was established by tone paired foot shock. Fear extinction was trained in 24 hours after establishment of fear memory. For extinction group and sham extinction group,retention test and immunnohistochemistry of Cdk5 were done at 2nd,4th and 8th day af- ter fear. Results （ 1 ） Retention scores of extinction group and sham extinction group were worse than naive group at 2nd and 4th days after fear（P 〈 0.01 ）, the scores of extinction group （ 71.04 ± 11.65 ） and naive group were better than sham extinction group（35.48 ± 12.37, P 〈 0.01 ） at 8th day after fear. （2）Cdk5 in IL of sham extinction group increased at 2nd day after fear（429± 70, P〈 0.05 ） ,the expression of extinction group＇s Cdk5 decreased at 4th day after fear（208 ± 30, P 〈 0.01 ） ,but it returned to normal at 8th day after fear. Conclusion The expression of Cdk5 in IL may increase after conditioned fear, but extinction may reduce its expression, which may be good for the early of conditioned fear extinction retention.

关 键 词：内侧前额叶 边缘下区 细胞周期素依赖性蛋白激酶5 恐惧消退 

分 类 号：R741[医药卫生—神经病学与精神病学]