摘要
[目的]研究N-甲基(酰)-D-门冬氨酸(NMDA)对小脑皮层浦肯野细胞(PC)自发性活动的影响,观察NMDA受体在小脑皮层中的作用.[方法]应用电生理和神经药理学手段观察外源性NMDA对乌拉坦麻醉小鼠小脑皮层PC自发性单纯性放电活动的影响,分析电生理实验数据.[结果]通过脑表面灌流NMDA活化小脑皮层NMDA受体,可导致小脑皮层PC自发性单纯性放电活动可逆性抑制.脑表面灌流浓度为25μmol/L的NMDA 10min后,PC自发性单纯性放电频率降低8.9%±2.3%(P<0.05),冲洗后恢复.当NMDA浓度增加至50μmol/L时PC自发性单纯性放电频率减少53.3%±3.5%(P<0.05);但对自发性单纯性放电的幅值和宽度无显著性影响.γ-氨基丁酸A(GABAA)受体阻断剂解除NMDA对PC自发性单纯性放电的抑制作用,同时可见外源性NMDA可引起的PC自发性单纯性放电频率增加.[结论]在成年小鼠小脑皮层,活化NMDA受体不能兴奋PC,反而通过GABAA受体抑制PC自发性单纯性放电活动,提示小脑皮层中间神经元网络在PC自发性活动和信息处理过程中起关键作用.
ABSTRACT： OBJECTIVE To study the effects of N-methyl-D-aspartate （NMDA） on spontaneous activity of cerebellar cortical Purkinje cells（PC） and the role of NMDA receptors （NMDA-Rs） in the cerebellar cortex. METHODS Using electrophysiological and pharmacological methods, the effects of exogenous NMDA on the spontaneous simple spike activity of cerebellar PCs were studied in urethane-anesthetized mice, and the electrophysiological data were analyzed. RESULTS Activation of cerebellar NMDA-Rs by brain surface perfusion of NMDA induced a reversible inhibition in spontaneous simple spike of cerebellar cortical PCs. Brain surface perfusion of 25mol/L NMDA for 10 rain, the mean of spontaneous simple spike firing rate of PC was decreased to 8.9% ± 2.3% （P〈0.05）, and recovered after washout. When the concentration of NMDA increased to 50 μmol/L, the spontaneous simple spike firing rate was reduced to 53.3%± 3.5% （P〈0.05）. However, brain surface perfusion of NMDA did not affect the amplitude and width of the simple spikes. GABAA receptor antagonist abolished the inhibitory effects of NMDA on PC spontaneous simple spike activity, and revealed a NMDA-induced increase in simple spike firing rate of PCs. CONCLUSION Activation of cerebellar cortical NMDA receptor in adult mice fails to excite PCs, but induces an inhibition in simple spike firin of PCs, and the results suest that the cerebellar cortical interneuron network lavs a criticalrole in the spontaneous activity and information processing of PCs.
出处
《延边大学医学学报》
CAS
2013年第1期1-5,共5页
Journal of Medical Science Yanbian University
