急性心肌缺血期大鼠丘脑束旁核神经元5-HT_(1A)受体mRNA表达的变化

Expression of 5-HT_(1A) receptor mRNA in the neurons of parafascicular nucleus following acute myocardial ischemia in rats

目的:观察急性心肌缺血期大鼠丘脑束旁核(para fascicularnucleus,Pf)神经元5-HT1A受体mRNA不同时点表达的变化,探讨5-HT1A受体在Pf痛觉整合和调制中的作用。方法:体重260～280g的健康成年雄性SD大鼠24只,随机分为4组,即非冠状动脉扎闭组(C组)、扎闭冠脉(coronaryarteryocclusion,CAO)1h组(CAO1h组)、扎闭冠脉3h组(CAO3h组)和扎闭冠脉6h组(CAO6h组)。C组仅在开胸后冠状动脉左前降支下穿线不予结扎,CAO各组则给予扎闭。在预定的时点处死动物,取含有Pf的脑片行原位杂交。杂交结果检测采用IDA-2000数码显微图像分析系统进行半定量分析。结果:CAO后1、3、6h大鼠Pf神经元5-HT1A受体mRNA的表达均较C组明显增强(P<0.05),随缺血时间延长其表达有逐渐增加的趋势,在CAO后6h表达最强(P<0.05)。结论:急性心肌缺血可诱发大鼠Pf神经元5-HT1A受体mRNA表达增强,5-HT1A受体参与急性心肌缺血伤害性刺激在Pf的调制。

To investigate the expression of 5-HT1A receptor mRNA in rat parafaseieular nucleus （Pf） following acute myocardial ischemia induced by coronary artery occlusion （CAO） in rats. Methods Twenty-four adult male SD rats, weighing 260 ～ 280 g, were randomly divided into four groups：Group C, the control group, with nonCAO;Group CAO 1 h, with CAO for 1 hour;Group CAO 3 h, with CAO for 3 hours;and Group CAO 6 h, with CAO for 6 hours, Coronary artery was occluded except Group C, Rats were killed at scheduled time points, and then the brains were dissected in order to perform in situ hybridization （ISH） of brain tissue cryo-section. Brain slices of Pf were examined and analyzed semi-quantitively for expression of 5-HT1A receptor mRNA by ISH technique with IDA-2000 digital micro-image analysis systems. Results The expression of 5-HT1Areceptor mRNA in rat Pf increased significantly at 1, 3 and 6 h after CAO as compared with that in Group C （P 〈 0.05）. The highest value was at 6 h in Group CAO 6 h （P 〈 0.05）. Conclusion Myocardial ischemia alone can cause the increase in the expression of 5-HT1A receptor mRNA in the neurons of rat Pf, which may be involved in central modulation of nociception of Pf evoked by acute myocardial ischemia.