部分毁损内嗅区皮质区对吗啡戒断大鼠行为学和海马结构CREB表达的影响

Partly Destroying Entorhinal Area Effects on Praxiology Indexes and CREB Protein Expression of Hippocampus Formation in the Withdrawal Rats

目的本探究使用兴奋型神经毒海人藻酸(kainate,KA)部分毁损海马结构信息的主要传入通路内嗅区皮质后,观察吗啡成瘾大鼠戒断时海马结构中CREB蛋白的表达变化及吗啡戒断鼠的行为学的变化。方法实验使用Wistar大鼠,随机均分为4组:①对照组:背部肩胛间皮下注射与实验组等体积的生理盐水;②戒断组:背部肩胛间皮下注射盐酸吗啡;③戒断注生理盐水组:在背部肩胛间皮下注射吗啡,再在内嗅区皮质注射生理盐水;④戒断注KA组:在背部肩胛间皮下注射吗啡,再在内嗅区皮质注射KA。对照组、戒断注生理盐水组和戒断注KA组连续注射6天吗啡,每天按体重增加吗啡量,使之快速成瘾;注射吗啡6天后,不再注射,开始观察戒断症状并在内嗅区皮质注射KA;戒断52h后,处死全部大鼠,用免疫组化染色方法观察各组大鼠海马结构内CREB蛋白的表达。结果①在戒断症状出现的高峰期,单纯戒断组与对照组相比大部分戒断症状的行为学指标都具有阳性意义;戒断注KA组与单纯戒断组或者戒断注射生理盐水组相比较大部分戒断症状的行为学指标下降较明显;戒断注KA组与对照组相比较大部分戒断症状的行为学指标差异不明显;②CREB在对照组、戒断组、戒断注生理盐水组以及戒断注射KA组的表达不同,其中在戒断注射生理盐水组的表达最高,其次为戒断组,在戒断注射KA组表达较低,而在对照组表达最低。结论毁损内嗅区皮质后吗啡成瘾大鼠的戒断症状明显减少,同时海马结构中的CREB表达减少,海马结构可能在大鼠CREB介导的成瘾记忆中有重要作用。

Objective Morphine addiction maybe relate with a special memorize.This memorize is possible majorly concerned with CREB signal transduction pathway.To investigate the function of hippocampal formation in withdrawal rats of morphine addiction,we observed the CREB protein expression changes,and researched the behavioral changes in withdrawal rats after partly destroyed the entorhinal cortex by administration of excited nervous poison-kainic acid.Methods Totally 40 Wistar rats were divided into 4 groups： ①Control group,only treated with subcutaneous injection of saline;②Withdrawal group,treated with subcutaneous injection of morphine;③Withdrawal Saline group,treated with subcutaneous administration of morphine before intra-nuclear injection of saline at entorhinal cortex;④Withdrawal KA group,treated with intra-nuclear injection of kainic acid at entorhinal cortex after subcutaneous injection of morphine.During 6 days rats in group ②,③ and ④ were continuously injected morphine according to body weight,to make all the rats quickly addict to morphine.The injection of morphine ceased after 6 days,then withdrawal syndromes were evaluated and started to treat with KA at endorhinal cortex.All the rats were killed at 52 hours after ceasing injection of morphine.Two-steps immunohistochemistry was used to observe the expression of CREB in Hippocampal Formation.Results ①At the crest-time of morphine abstinent syndromes,largely kinds of withdrawal syndromes had significant difference in Withdrawal group comparing with control group,but the scores in Withdrawal KA group comparing with control group had no significant difference.②Expressions of CREB protein in various groups were different,and the expression was highest in withdraw saline group,higher in withdraw group,lower in withdrawal KA group,and lowest in control group.Conclusion Withdraw syndromes were obviously decreased in Withdrawal KA group after destroying entorhinal area,meanwhile expression of CREB protein was also decreased,which may indicate that hippocampal formation plays an important role in the addiction memory mediated by CREB.