THRESHOLD CONDITIONS FOR INITIATION OF ACTION POTENTIALS BY EXCITABLE CELLS
THRESHOLD CONDITIONS FOR INITIATION OF ACTION POTENTIALS BY EXCITABLE CELLS
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DOI：
10.1113/jphysiol.1966.sp008079
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发表时间：
1966-01-01
影响因子：
5.5
通讯作者：
STEIN, RB
中科院分区：
文献类型：
--
作者：
NOBLE, D;STEIN, RB
分析了均匀极化的可激膜和一点极化的可激索的刚阈刺激强度与持续时间的关系（强度-持续时间曲线）。膜电流-电压关系的非线性对强度-持续曲线的影响与时间无关。分析了有限膜活化时间和膜互换性对电流-电压曲线随时间变化的影响。将Hodgkin-Huxley膜方程（Hodgkin and Huxley, 1952）的强度-持续时间曲线与Hill（1936）的双时间常数模型进行了比较。导出了稳态条件下膜电流-电压曲线与点极化电缆的关系。电缆的特性倾向于使电流-电压曲线线性化，并使电压阈值锐化。本文用数值方法计算了薄膜符合霍奇金-赫胥黎方程的点极化电缆的强度-持续时间曲线。恒流通过时电荷的重新分配对电缆强度-持续时间曲线有较大的影响；得到的强度-持续时间曲线在Hill模型预测的曲线范围内。恒定电荷阈值所需的条件（Hodgkin和Rushton， 1946）表明，在某一点上对电缆施加短而强烈的刺激是可以满足的。并结合已有的实验研究对所得结果进行了讨论。
The relationship between the strength and duration of a just threshold stimulus (strength-duration curve) is analysed for an excitable membrane polarized uniformly and for an excitable cable polarized at one point. The effect on the strength-duration curve of non-linearity in the membrane current-voltage relation is independent of time. The effects of changes in the current-voltage curve with time due to the existence of a finite membrane activation time and membrane ac -commodation are analyzed. The strength-duration curve for the Hodgkin-Huxley membrane equations (Hodgkin and Huxley, 1952) is compared to that of Hill''s (1936) two-time constant model. The relation between membrane current-voltage curves and those for a point-polarized cable are derived for the steady-state condition. The cable properties tend to linearize the current-voltage curve and to sharpen the voltage threshold. The strength-duration curve for a point-polarized cable whose membrane obeys the Hodgkin-Huxley equations is computed numerically. There is an additional large effect on the cable strength-duration curve arising from the redistribution of charge during passage of a constant current; and the resulting strength-duration curve lies within the range of curves predicted by Hill''s model. The conditions required for a constant charge threshold (Hodgkin and Rushton, 1946) are shown to be satisfied for short, intense stimuli applied to a cable at one point. The results are discussed with reference to the experimental studies available.