条件性恐惧消退早期大鼠边缘下区NR2B的动态变化  

Changes of NR2B in infra-limbic cortex after fear extinction

作　　者：韦美[1,2] 李敏[1] 李培培[1] 张丽丽[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 [2]白求恩国际和平医院256临床部,河北正定050800

出　　处：《第三军医大学学报》2010年第3期220-223,共4页Journal of Third Military Medical University

基　　金：国家自然科学基金(30670712);重庆市自然科学基金(CSTC2009BB5014)~~

摘　　要：目的探讨条件性恐惧消退早期(1周内),记忆保持成绩与内侧前额叶皮层边缘下区(infra-limbic cortex,IL)NMDA受体2B亚基(NR2B)免疫反应阳性物质的动态变化。方法将70只成年雄性SD大鼠随机分成:正常对照组、恐惧消退组和恐惧对照组,其中恐惧对照组(条件恐惧建立后不进行消退训练),恐惧消退组(条件恐惧建立24 h后进行消退训练),采用以声音为提示的足底电击建立大鼠恐惧记忆,然后仅给予声音信号进行恐惧消退训练。在恐惧消退后第1、3、7天分别进行消退保持测试,并在各时间点取边缘下区标本进行NR2B的免疫组化实验。结果在消退保持过程中:①恐惧对照组和恐惧消退组大鼠消退成绩整体呈上升趋势,但均低于正常对照组,恐惧消退组消退成绩好于恐惧对照组(P<0.01);②恐惧对照组和恐惧消退组大鼠边缘下区NR2B免疫反应阳性物质逐渐增加,但均低于正常对照组,第1天无明显差异,第3、7天差异明显,恐惧消退组NR2B免疫反应阳性物质高于恐惧对照组(P<0.05)。结论恐惧消退训练后3～7 d,边缘下区NR2B水平与消退记忆保持成绩一致。Objective To observe the changes of N-methyl-D-aspartate （NMDA） receptor 2B, an immune positive reaction substance, in infra-limbic （IL） cortex of medial prefrontal cortex （mPFC） in adult rats after fear extinction. Methods Twenty-four hours after Pavlovian fear conditioning, 70 rats were randomly divided into fear extinction group （ n = 30 ）, natural extinction group （ n = 30 ） and naive group （ n = 10 ）. Extinction memory was established by electric shock at the sole with tone as a prompt. Then, fear extinction training was carried out by giving the rats only tone signals. NR2B was tested by immunohistochemistry 1, 3 and 7 d after fear extinction. Results The NR2B expression level increased gradually in fear and natural extinction groups and was lower than that in normal control group. The fear extinction was better in natural extinction group than in normal control group （P 〈 0.05 ）. The NR2b level increased gradually in IL cortex of fear and natural extinction groups, and was lower than that in normal control group. A significant difference was found on day 1 but not on days 3 -7. Conclusion NR2B level in IL cortex is consistent with the extinction memory 3 -7 d after fear extinction training.

关 键 词：恐惧消退 NR2B 前额叶 边缘下区 

分 类 号：R395.1[哲学宗教—心理学] R338.26[医药卫生—医学心理学]