杏仁核点燃癫痫大鼠nNOS的表达及抗癫痫药物的影响

nNOS EXPRESSION IN AMYGDALA KINDLED RATS AND EFFECTS OF ANTI-EPILEPSY DRUGS

目的建立大鼠杏仁基底外侧核电点燃模型,测定大鼠海马nNOS的表达情况并观察常用抗癫痫药物对nNOS表达的影响,探讨癫痫的可能发病机制及常用抗癫痫药的药理作用。方法把双极电极插入大鼠左侧杏仁基底外侧核,给予慢性电刺激使大鼠达到点燃状态。设立空白对照组、手术对照组、电点燃癫痫组及托吡酯、丙戊酸钠、卡马西平治疗组,采用半定量RT-PCR法检测各组大鼠海马组织nNOS mRNA的表达,并用免疫组织化学法检测各组大鼠海马组织中nNOS的表达。结果杏仁核点燃癫痫组大鼠海马组织中nNOS较空白及手术对照组明显升高,经药物治疗后的nNOS表达出现明显下调,其中托吡酯组与其他两个药物组相比nNOS表达增高,差异具有显著性。免疫组化结果表明nNOS定位于神经元胞浆,癫痫组及托吡酯治疗组的强阳性表达率高于对照组及其他治疗组。结论杏仁核点燃癫痫大鼠海马组织nNOS表达明显增加,提示nNOS可能参与了杏仁核点燃癫痫的形成过程;抗癫痫药物明显减少了nNOS的表达,有利于保护正常的神经细胞功能。

Objectives We aimed to address the involvement of the neuronal nitric oxide synthase （nNOS） in epilepsy, especially to construct a rat model of basolateral amygdala kindling, quantify the nNOS expression in hippocampus, test the effects of commol/Lonly as anti-epilepsy drugs on the preceding factor, and discuss the possible pathogenesis of epilepsy and the mechanisms for therapies. Methods Bipolar electrodes were implanted in the left side of the rat basolateral amygdala, and chronic electric stimuli were delivered to reach the kindling threshold. A blank control group, a sham group, an electrically kindled epilepsy group, and three therapy groups （with topiramate, sodium valproic acid and carbamazepine respectively） were set up. Semi-quantitative RT-PCR was employed to examine the nNOS mRNA levels in the hippocampus of each group, and immol/Lunohistochemistry methods were used to determine the hippocampal expression of nNOS in each group. Results Hippocampal expression of nNOS was significantly higher in the kindled group than in the blank control and the sham group. In the therapy group, nNOS expression was markedly down-regulated relative to the epilepsy group, and the topiramate group was noticeably higher than the other two therapy groups. The immol/Lunohistochemistry results located the nNOS expression in the neuronal cytosol, and the high positive expression rate was shown to be higher for both of the epilepsy and the topiramate group than the sham control, blank control and the other two therapy groups. Conclusions The large increase of nNOS expression in the amygdala kindled rat hippocampus suggests the possible involvement of nNOS in amygdala kindled epilepsy. Routine antipilepsy medicines were observed to be effective in decreasing hippoeampal nNOS expression, and thus might be beneficial to the protection of normal neuronal functions in epilepsy.