海马脑片CA_1区LTP的诱出以及3种致惊厥剂对其影响

Long-term potentiation and the effects of 3 convulsants on its induction in hippocampal slices of rats

本文采用离体海马脑片技术,观察大鼠海马CA_1区突触传递的长时程增强(LTP),并比较3种致惊厥剂对其诱出的影响。结果发现:短串电刺激在大多数脑片有效地诱出LTP;印防己毒素(PTX)在诱发痫样电活动的同时,易化LTP诱出;红藻氨酸(KA)则阻滞LTP诱出;梭曼(Soman)没有诱发明显的痫样电活动,但阻滞LTP诱出。结果提示:PTX和KA诱发的痫样电活动对LTP诱出的不同影响可能因其各自产生机制不同所致;Soman对诱发场电位的影响可能除通过胆碱能系统外,还通过如谷氨酸能系统等非胆碱能系统。

Long-term potentiation (LTP) of synaptic transmission between the dendrites of the pyramidal cells of CA[ region and the Schaffer-commissu-ral pathway was induced with electric stimulation in the isolated hippocampal slices of rats.The effects of 3 convulsants,soman,kianic acid.and picroto-xin,on the induction of LTP in this region were observed.It was found that a short series of electric impulses could effectively induce LTP in most of the slices of the hippocampus and the amplitude of the population spikes showed a similar change as the field excitatory postsynaptic potential did in the rising phase.Picrotoxin could facilitate the induction of LTP when it evoked an epileptoform electric activity in the slices,kianic acid could also evoke an epileptoform activity but significantly blocked the induction of LTP,and soman could not evoke obvious epileptoform activity but blocked the induction of LTP.The above findings suggest that a short series of electric impulses can effectively induce LTP between the pyramidal cells and the Schaffer-commisural pathway in the CA1 region,the effects of epileptoform activity on the induction of LTP depends on the mechanism to evoke the epileptoform activity,and the effects of soman on the induction of field potential may involve the noncholi-nergic system in the synaptic connections.