蟾蜍脊神经节神经元对外周重复刺激的反应

RESPONSES OF TOAD SPINAL GANGLION NEURONS IN VITRO TO PERIPHERAL REPETITIVE STIMULATION

本工作用细胞内记录技术,研究并分析了蟾蜍离体脊神经节神经元对重复刺激其外周突(坐骨神经)的反应。所记录的66个神经元的传导速度,刺激阈值和静息膜电位分別为5.3—20.0m/s,0.02—0.10mA 和-50—-80mV。随着重复刺激频率的增加,脊神经节神经元的细胞内动作电位进行性地出现潜伏期动摇或延迟、振幅降低、后超极化减弱和时程延长。与此同时,锋电位分解成 S、NM 和 M 三种亚波成分,并进而出现脱失。S、NM 和 M 成分对刺激频率的跟随能力为 S<NM<M,锋电位或 S 波出现脱失的频率范围为16.7—250Hz。结果提示,蟾蜍脊神经节 A 型神经元具有三个兴奋性显著有别的区域;部分 A 型神经元可能具有突触或接头性活动。

Responses of toad ganglion neurons in vitro to repetitive stimulation of theirperipheral processes(sciatic nerve)were intracellularly recolded.The con-duction velocity,threshold and resting membrane potential of the 66 recordedneurons ranged 5.3—20.0 m/s,0.02—0.10mA,and—50—80 mV,respectively.As the stimulation frequency increased,jitter or delay in onset latency,reductionin amplitude,prolongation in duration,and decrease in afterhyperpolarizationoccurred in evoked responses of the spiral ganglion neurons.The responsesdecomposed into three subwaves of S,NM,and M and then missed.The abilityof these three components to follow stimulation frequency was in the order of S<NM<M;the frequency range during which the spike potential or wave S misseswas from 16.7 Hz to 250 Hz.These results indicate that there are three distinct zones in excitability intype A toad spinal ganglion neurons,and some of them may exhibit synaptic orjunctional activity.