皮层抑制对大鼠丘脑底核自发放电的影响

EFFECT OF CORTICAL SPREADING DEPRESSION ON SPONTANEOUS FIRING ACTIVITIES OF STN NEURONS IN RATS

目的:观察皮层抑制对正常及帕金森病(PD)大鼠丘脑底核(STN)神经元自发放电的影响。方法:采用玻璃微电极细胞外记录法,观察正常和PD大鼠STN神经元的放电活动及脑内微量注射KCl后,两组大鼠STN神经元放电频率的变化。结果:对照组和PD组大鼠STN神经元放电频率分别为(9.78±0.71)Hz和(23.81±1.08)Hz,PD组大鼠放电频率显著高于对照组(P<0.01),且呈爆发式放电的神经元比例明显高于对照组(P<0.05)。皮层注射KCl后,经过较长的潜伏期,两组大鼠STN神经元放电频率均明显降低,后缓慢恢复。结论:PD大鼠STN神经元放电频率增高,爆发式放电增多,而抑制皮层可使这种异常放电得到改善,提示皮层兴奋性的改变可能是PD中STN活动增强的另一个诱因。

To observe the effect of cortical spreading depression （CSD） on the spontaneous firing activities of neurons of subthalamic nucleus （STN） in normal and model rat of Parkinson＇s disease （PD）. Methods： Extracellular recording was used to research the neuronal electric activities in subthalamic neurons. The changes of the discharge rotes of subthalamic neurons were observed in control and PD rats after intracortical microinjection of KCl solution. Results： The discharge rates of subthalamic neurons in control and PD rats were（9.78 ± 0.71）Hz and （23.81 ±1.08）Hz, respectively. The discharge rate of PD rats was increased significantly when compared with those of the control rats and the percentage of neurons discharging in bursts was obviously higher than those of control rats （P〈 0.01）. After a long latent period secondary to intracortical injection of KCl solution, the discharge rates in both group of subthalamic neurons were decreased apparently, then recovered slowly. Conelusion： The discharge rate and bursting pattern are increased in PD rats and these abnormal activities can be improved by cortical depression. This result indicates that the changes in cortical excitability may be one of the factors increasing the activity of STN in PD.