尼古丁增强大鼠场景性恐惧记忆再巩固  

Nicotine Selectively Enhances Reconsolidation of Contextual Fear Memory in Rats

作　　者：李振邦[1] 李传玉[1] 黄伏连[1] 田绍文[1] 

机构地区：[1]南华大学医学院生理学教研室,湖南衡阳421001

出　　处：《南华大学学报（医学版）》2009年第3期254-256,共3页Journal of Nanhua University(Medical Edition)

基　　金：国家自然科学基金(30770689);湖南省教育厅优秀青年基金(05B045)

摘　　要：目的探讨恐惧记忆再巩固的胆碱能机制。方法将64只SD大鼠随机分为场景性任务组(32只)、非特异性僵直检测组(16只)和场景性恐惧记忆巩固检测组(16只)。场景性任务组内将SD大鼠又随机分为4个剂量组,每个剂量组8只动物,分别给予尼古丁0.25、0.5、1.0 mg/kg和生理盐水1 mL/kg皮下注射;非特异性检测组内将16只SD大鼠又随机分为两个剂量组,每个剂量组8只动物,分别给予尼古丁1.0 mg/kg和生理盐水1mL/kg皮下注射;场景性恐惧记忆巩固检测组内将16只SD大鼠又随机分为两个剂量组,每个剂量组8只动物,分别给予尼古丁1.0 mg/kg和生理盐水1 mL/kg皮下注射。各组大鼠习惯化训练后24 h进行恐惧条件化训练,条件化后24 h进行恐惧记忆再激活,再激活训练后立即皮下给予尼古丁或生理盐水注射,24 h后进行恐惧记忆再巩固,检测的指标为声音或场景诱发的大鼠僵直行为。结果在场景性任务中,尼古丁1.0 mg/kg组与生理盐水组大鼠僵直时间在恐惧条件化、再激活阶段差异均无显著性,但在再巩固检测阶段,尼古丁组大鼠僵直时间显著高于生理盐水组大鼠(P<0.05)。结论急性尼古丁处理能增强场景性恐惧记忆再巩固。Objective To examine the cholinergic mechanisms of reconsolidation of fear memory. Methods 64 rats were divided randomLy into three groups ： contextual fear memory task group （ n = 32 ） , non - specific freezing test group （n = 16 ） and consolidation of fear memory test group （n16）. In contextual fear memory task group, rats were divided randomLy into four groups（ n = 8 per group. Rats were acute treated by s.e. injection of nicotine （0.25,0.5 or 1 mg/kg （ or saline 1 mL/kg. In non - specific freezing test group, rats were divided randomLy into two groups （ n = 8 per group ）. Rats were acute treated by s. c. injection of nicotine 1 mg/kg or saline 1 mL/kg. In consolidation of fear memory test group, rats were divided randomLy into two groups （ n = 8 per group ）. Rats were acute treated by s.c. injection of nicotine 1 mg/ kg or saline 1 mL/kg. Rats received fear conditioning session 24 h after a habituation session. Rats received fear memory retrieval session and a reconsolldation test session 24 and 48 h after conditioning, respectively. In the tasks above, rats were acute treated by s.c. injection of nicotine or saline immediately after retrieval session. Freezing induced by tone or context was assessed during all phases of training. Results In contextual fear memory task, the 1.0 mg/kg nicotine group showed higher level of freezing time than the saline group in the reeonsolidation test session （ P 〈 0.05 ）, but there was no significant difference in freezing time between the two groups in fear conditioning session and reeonsolidation training session. Conclusion Acute nicotine can enhance reconsolidation of contextual fear memory.

关 键 词：尼古丁 再巩固 大鼠 

分 类 号：R338[医药卫生—人体生理学]