帕金森病大鼠内侧前额叶皮层神经元电活动及5-HT1A受体表达的变化

摘要

Objective : To investigate changes in the firing rate and pattern of interneurons in the medial prefrontal cortex (mPFC), and expression of 5-HT1A receptor in rats with 6-hydroxydopamine (6-OHDA) Lesions of the substantia nigra pars compacta (SNec) . Methods : By using of vivo extracellular recordings ,the activity of mPFC pyramidal neurons in 6-OHDA-lesioned rats was investigated ; then the altered expression of 5-HT1A receptor in mPFC of PD model rats was analysed by immunocytochemical SP technique. Results : The firing rate was significantly increased, mean ISI coefficient and percentage of burst-firing neurons were significantly increased in 6-OHDA-lesioned rats when compared with that normal rats. The counting of 5-HT1A receptor positive cells in the mPFC was obviously reduced in the lesioned side of PD rats when compared with nomal rats; the expression intensity of 5-HT1A receptor positive cells from the layer Ⅱ to Ⅵ in the mPFC of normal group was not affected . same as in the layer Ⅱ of PD group.whereas the layer Ⅲ to Ⅵ of PD group reduced evidently. Conclusion : The results suggest that 5-HT1A receptor dysfunction in the lesioned side mPFC of PD rats, the mPFC pyramidal neurons are hyperactive.%目的:探讨帕金森病(PD)模型大鼠内侧前额叶皮层(mPFC)神经元电活动及5-HT1A受体表达的变化.方法:采用玻璃微电极细胞外记录的方法,在体观察6-OHDA单侧损毁大鼠黑质致密部(SNc)后,mPFC中锥体神经元放电频率和放电形式的变化;采用免疫组织化学SP法,观察PD大鼠mPFC中神经元5-HT1A受体表达的变化.结果:与对照组相比,PD大鼠mPFC锥体神经元平均放电频率显著增加、变异系数明显增大、具有爆发式放电的神经元比例显著增多.PD组大鼠损毁侧mPFC 5-HT1A受体阳性细胞明显稀疏;对照组大鼠mPFC的Ⅱ～Ⅵ层均表达较丰富的5-HT1A受体阳性细胞;PD大鼠mPFC的Ⅱ层表达也较丰富,但Ⅲ～Ⅵ层表达明显稀疏.结论:PD时mPFC神经元上的5-HT1受体功能失调,mPFC中的锥体神经元呈过度活动.