马桑内酯在大鼠离体海马脑片上引起的癫痫样放电活动

Coriaria Lactone-Induced Epileptiform Activity in the Hippocampal Slices of Rat

采用大鼠离体海马脑片技术,建立了马桑内酯(Coriaria lactone,CL)引起的海马CA 1区锥体细胞癫痫样放电活动模型,并初步探讨了CL的致痫作用机理,可能与直接影响锥体细胞固有爆发放电能力有关。

Coriaria lactone(CL)is an active consti-tuent of a medicinal herb used as psycho-solytic in traditifnal Chinese medicine. Re-cently it has been found that CL appears toact as a convulsant agent. Subsequently bothacute and chronic epilepsy models causedby CL have been established successfully.In order to observe further the epilepto-genic effects of CL in vitro, the hippocampalslice technique was used in experimentswith 36 slices. The results are as follows:Addition of CL to the perfusion bathing theslices of rat hippocampus increased evoked-response in body layer of CA1 in a dose-dependent manner, and induced epileptiformburst. CL augmented population spike ofCA1 pyramidal neurons triggered by eitherorthodromic stimulus (through synapses) orantidromic stimulus (direct effect on theaxon of CA1 pyramidal cells)without altera-tion of presynaptic fiber volley and field-EPSP, and there was no significant changein latency of burst. Finally GABA had aweak effect on CL-induced epileptiform ac-tivity. These observations suggest that CLprobably has a direct effect on the soma ofpyramidal neurons, CL-induced epileptiformburst may be a result of altering the innatecapcity of burst and increasing the intrinsicexcitability of pyramidal cell membranes.