Hentall I D
Department of Physiology and Biophysics, University of Puerto Rico Medical Sciences Campus, School of Medicine, San Juan.
P R Health Sci J. 1988 Aug;7(2):144-8.
The steady-state cable equations were used to describe the response of discontinuous neuronal cylinders to extracellular electric fields. Where two unequal diameters join, there forms a strong local peak of membrane polarization. Under fields of constant gradient, this peak roughly equals the drop in external voltage over the distance given by the larger length-constant. In contrast, altering the specific membrane resistance along part of a uniformly shaped axon affects the general level of membrane potential without causing a local peak. Field-effects due to structural discontinuities, although relevant to the interpretation of experiments using electrical stimulation, are shown to be of minor functional consequence compared to chemical gating of membrane current.
稳态电缆方程用于描述不连续神经元圆柱体对细胞外电场的响应。在两个不等直径的连接处，会形成一个强烈的局部膜极化峰值。在恒定梯度场下，这个峰值大致等于外部电压在由较大长度常数给出的距离上的下降。相比之下，沿均匀形状轴突的一部分改变比膜电阻会影响膜电位的总体水平，但不会引起局部峰值。尽管结构不连续性引起的场效应与使用电刺激的实验解释相关，但与膜电流的化学门控相比，其功能影响较小。
