大鼠脑前扣带皮层(ACC)兴奋性与厌恶情绪的行为-电生理学观察

Excitatory and aversive behaviors-electrophysiological observation of anterior cingulate cortex(ACC)in rats

目的:探讨激活大鼠ACC脑区的阿片受体降低伤害刺激引起厌恶情绪的作用。方法:将实验大鼠随机分为7组,完全弗氏佐剂(CFA)+生理盐水(NS)组,生理盐水(NS)+生理盐水(NS)组,生理盐水(NS)+0x0E?SymbolmA@0x0F-阿片受体激动剂([DAla 2,NMe-Phe 4,Gly-ol 5]enkephinlin,DAMGO)组,完全弗氏佐剂(CFA)+0.01/0.04/0.2/1μg/μl DAMGO组(n=6)。实验周期为3 d,第1日测量基础值,第2日预先通过ACC区域给药1μl,然后将0.08 ml完全弗氏佐剂(CFA)注射到大鼠左后脚掌,第3日观察大鼠的CPA反应、缩足反射潜伏期(PWL)和ACC脑区的电活动。结果:①皮下注射CFA的大鼠,注射前与注射后相比,PWL明显减少(P<0.05);②在笼具痛侧,CFA组大鼠停留的时间明显少于非痛侧(P<0.05);③在ACC脑区预先注射0.04/0.2/1μg/μl DAMGO可明显减弱C-CPA反应(P<0.05);④在ACC脑区预先注射0.04/0.2/1μg/μl DAMGO可以降低CFA诱发ACC脑区放电频率的增加(P<0.05)。结论:激活了大鼠ACC脑区上的μ-阿片受体可以降低伤害性刺激诱发的厌恶情绪的发生。

Objective:Increasing activities in anterior cingulate cortex(ACC)can enhance the aversion reactions associated with noxious stimuli.It has been known that opioid receptors activation can trigger endogenous analgesic effect.This study tried to explore whether opioid receptors activation in the ACC region could reduce the aversion associated with noxious stimuli.Methods:The experimental rats were randomly divided into seven groups,Complete Freund's adjuvant(CFA)+normal saline(NS)group,normal saline(NS)+normal saline(NS)group,normal saline(NS)+DAMGO((DAla 2,NMe-Phe 4,Gly-ol 5)enkephinlin,μ-opioid receptor agonist)group,complete Freund's adjuvant(CFA)+0.01/0.04/0.2/1μg/μl DAMGO group(n=6).The experimental period was three days.The basal value was measured on the first day.The second day,1μl was administered through the ACC area,and then 0.08 ml of complete Freund's adjuvant(CFA)was injected into the left hind paw of the rat.CPA response,paw withdrawal reflex latency(PWL)and electrical activity in the ACC brain region of rats were observed on the third day.Results:①PWL was significantly decreased in rats after CFA was injected into left hind paw compared with post-injection(P<0.05).②In the pain side of the apparatus,it took rats less residence time than that in the non-pain side.③0.04/0.2/1μg/μl DAMGO was given before CFA-injection,C-CPA reactions could be revised significantly.④Given 0.04/0.2/1μg/μl DAMGO in the ACC region could decrease the increasing discharge frequency induced by CFA in ACC neurons.Conclusion:The activation of the mu-opioid receptor in the ACC region alleviates the aversion induced by noxious stimulation.