螯虾神经轴突上双微电极细胞内刺激与记录及其实验观察

本文以螯虾细小神经轴突为标本,成功地应用双玻璃微电极进行细胞内刺激与电活动的记录。观察了细小神经轴突膜电生理和物理特性参数。钾离子通道特异性阻滞剂4—氨基吡啶,使Weiss式中常数b值显著减少;a值无明显变化;膜静息电位去极化;阈电位水平上移;动作电位幅值、锋电位时程、膜电阻和膜时间常数均有显著意义的增加。结果提示:4—氨基吡啶可提高膜的应激性,对神经膜兴奋性无明显影响;生物膜应激性及膜电阻的变化与钾通道的活动状态有密切关系。

OBSERVATIONS OF INTRACELLULAR STIMULATING AND RECORDING BY TWO GLASS MICROELECTRODES ON THE CRAYFISH AXON

Intracellular stimulating and recording method was used by two glass microelectrodes on crayfish small axon. Physiologic and physical parameters of small nerve fiber were measured. 4—aminopyridine (4-AP). a selective inhibitor of the potassium channel,made"b" (an irritability index,a constant in Weiss's formula) decreased(p<0. 01) and "a" (an excitability index,another constant in Weiss's formula)unchanged ,the resting potential depolarized (P<0. 01), the threshold potential level raised (P<0.05),the membrane resistance and membrane time constant increased significantly. The results suggested that 4-AP can increase membrane irritability , but not affect the membrane excitability; the changes of membrane irritability and membrane resistance were related to the inhibition and activation of potassium channel.