缺血对大鼠小脑浦肯野细胞动作电位编码的影响

目的:通过减慢小脑蚓部矢状切片灌流速度来模拟缺血,探讨缺血早期小脑浦肯野细胞内在电生理特性的变化及其可能机制。方法:取小脑蚓部做矢状切片(400μm),通过Axoclamp-2B放大器全细胞记录模式记录缺血后浦肯野细胞动作电位的阈电位和不应期的电信号,并输入pClamp 9.2软件获取和分析群集发放的动作电位间距和动作电位峰时程标准差,进行数据采集和分析,观察缺血时浦肯野细胞内在电生理特性的变化。结果:在减慢脑片灌流速度后的短时间内,小脑浦肯野细胞群集发放的动作电位的不应期缩短和激发动作电位的阈电位降低(P<0.01)。结论:缺血改变动作电位的不应期和阈电位,使浦肯野细胞过度兴奋,动作电位的编码能力降低。

Influence of ischemia on spike encoding at cerebellar Purkenje cells in rats

Objective： To study the changes of the intrinsic electrophysiological characteristics of cerebellar Purkinje cells and the possible mechanisms during the early stage of simulated ischemia by reducing the perfusion to the sagittal slices of cerebellar vermis in rat. Methods： The sagittal slices of cerebellar vermis （400μm） were prepared. The recordings of threshold potentials of firing spikes and refractory periods following each Spike of simulated ischemia cells were conducted in a whole-cell model with an Axoclamp-2B amplifier; and the electrical signals were input into pClamp 9.2 for data acquisition, analysis of inter-spike interval and standard deviation of spike timing,in order to detect the changes in the intrinsic electrophysiological properties at Purkinje neurons during the simulated ischemia. Results ：Shortly after reducing the perfusion rate ,refractory periods of sequential spikes were shortened and the threshold potentials of firing spikes lowered （P 〈 0. 01 ）. Conclusions： The ischemia changes the refractory periods and the threshold potentials of sequential spikes,which causes over-excitation of cerebellar Purkinje cells and deteriorates spike encoding at cerebellar Purkinje cells.