A Study of Epileptiform Hippocampal Unit Activity Induced by Intracerebroventricular Injection of Kainic Acid in Rats  

作　　者：郭庆 刘祚周 廖维宏 

机构地区：[1]Department of Physiology, Third Military Medical College, Chongqing

出　　处：《Journal of Medical Colleges of PLA(China)》1989年第3期272-276,共5页中国人民解放军军医大学学报（英文版）

摘　　要：Hippocampal EEG and unit activities were recorded after seizures were initiated withintracerebroventricular injection of kainic acid (KA) in rats. Three kinds of hippocampal unit re-sponses to KA were found:1. Positive units: These units were characterized by high frequency burst firing temporally coincidentwith each hippocampal EEG spike.2. Negative units: These units showed a cessation of firing during each EEG paroxysm.3. Indifferent units: These units showed no evident chanses coincident with EEG paroxysms.Most positive units were hippocampal complex spike cells which correspond histologically tohippocampal pyramidal cells, and most complex spike cells fired in positive bursts after KA treat-ment. In the early period after KA injection, the positive units were concentrated in CA3 area. It was suggested that the activities of positive units may be considered as the typical epileptiformhippocampal unit activity induced by KA, and the firing features of negative units ma be the resultof the influence of hippocampal inhibitory interneurons or the result of excessive cellulardepolarization, and that hippocampal pyramidal cells were more sensitive to the epileptogenic ef-fect of KA than hippocampal intemeurons, and some pyramidal cells in CA3, in particular,may serve as "epileptic pacemaker neurons " in KA-induced epileptogenesis.Hippocampal EEG and unit activities were recorded after seizures were initiated with intracerebroventricular injection of kainic acid (KA) in rats. Three kinds of hippocampal unit re- sponses to KA were found: 1. Positive units: These units were characterized by high frequency burst firing temporally coincident with each hippocampal EEG spike. 2. Negative units: These units showed a cessation of firing during each EEG paroxysm. 3. Indifferent units: These units showed no evident chanses coincident with EEG paroxysms. Most positive units were hippocampal complex spike cells which correspond histologically to hippocampal pyramidal cells, and most complex spike cells fired in positive bursts after KA treat- ment. In the early period after KA injection, the positive units were concentrated in CA3 area. It was suggested that the activities of positive units may be considered as the typical epileptiform hippocampal unit activity induced by KA, and the firing features of negative units ma be the result of the influence of hippocampal inhibitory interneurons or the result of excessive cellular depolarization, and that hippocampal pyramidal cells were more sensitive to the epileptogenic ef- fect of KA than hippocampal intemeurons, and some pyramidal cells in CA3, in particular, may serve as 'epileptic pacemaker neurons ' in KA-induced epileptogenesis.

关 键 词：TEMPORAL LOBE EPILEPSY kainic acid HIPPOCAMPUS unit activity rat 

分 类 号：R[医药卫生]