应激损害吗啡奖赏记忆再巩固及其对海马CA1脑区活性调节细胞骨架蛋白（Arc）表达的影响

目的：观察应激是否损害吗啡奖赏记忆再巩固及其对海马活性调节细胞骨架蛋白（Arc）的影响。方法：（1）建立大鼠吗啡条件位置偏爱（conditioned place preference,CPP）模型,给予不同的处理即暴露、应激、暴露后立即应激,观察应激对吗啡奖赏记忆再巩固的作用。（2）建立吗啡CPP模型,暴露6 h后应激,观察应激损害吗啡奖赏记忆再巩固是否存在时间窗。（3）处理测试后的大鼠断头取脑,采用免疫荧光法和Western blot法分析应激对吗啡CPP大鼠海马Arc表达的影响。结果：（1）吗啡奖赏记忆唤起后立即给予应激,其再巩固受到损害（P〈0.05）。（2）应激损害吗啡奖赏记忆再巩固作用存在时间窗（P〈0.05）。（3）暴露后给予应激组大鼠在CPP测试后海马CA1脑区中的Arc表达下降（P〈0.05）。结论：（1）应激可损害吗啡奖赏记忆再巩固,且其作用具有时间窗。（2）应激损害吗啡记忆再巩固可能与其降低海马CA1脑区的Arc表达有关。

EFFECTS OF STRESS ON RECONSOLIDATION OF MORPHINE- INDUCED REWARDING MEMORY AND EXPRESSION OF ACTIVITY- REGULATED CYTOSKELETON- ASSOCIATED PROTEIN IN HIPPOCAMPAL CA1

Objective：To investigate whether stress impairs the reconsolidation of morphine - induced rewarding memory and affects the expression of Arc （activity- regulated cytoskeleton - associated protein, Arc ）. Methods： （ 1 ） Rats were trained for morphine - induced conditioned place preference （CPP）. Then, rats were divided into four groups to test the effect of stress administered immediately after exposure to morphine -paired context： no exposure ＋ no stress; no exposure ＋ stress ; exposure ＋ no stress ; exposure ＋ stress ; （2） Rats were trained for morphine - induced CPP and then were divided into two groups to test the effect of stress administered 6 hours after exposure to morphine - paired context ： no exposure ＋ 6 h ＋ stress ; exposure ＋ 6 h ＋ stress; （3） The rats were decapitated for measurement of Arc expression in the CA1 after the CPP test by Western blot and immunofluorescence assay. Results： （ 1 ） Stress administered immediately after exposure to morphine - paired context impaired the reconsolidation of morphine rewarding memory. （2） However, stress administered 6 hours, outside of the time window of the reconsolidation, after the exposure to morphine - paired context had no effect on the morphine rewarding memory. （3） The impairment of reconsolidation of morphine rewarding memory is related to decreased expression of Arc. Conclusion：Stress administeredimmediately, but not 6 hours, after exposure to morphine - paired context impaired the reconsolidation of morphine rewarding memory and decreased the expression of Arc in the CA1.