Plonsey R, Barr R C
Biophys J. 1987 Apr;51(4):547-55. doi: 10.1016/S0006-3495(87)83380-5.
The electrical source strength for an isolated, active, excitable fiber can be taken to be its transmembrane current as an excellent approximation. The transmembrane current can be determined from intracellular potentials only. But for multicellular preparations, particularly cardiac ventricular muscle, the electrical source strength may be changed significantly by the presence of the interstitial potential field. This report examines the size of the interstitial potential field as a function of depth into a semi-infinite tissue structure of cardiac muscle regarded as syncytial. A uniform propagating plane wave of excitation is assumed and the interstitial potential field is found based on consideration of the medium as a continuum (bidomain model). As a whole, the results are inconsistent with any of the limiting cases normally used to represent the volume conductor, and suggest that in only the thinnest of tissue (less than 200 micron) can the interstitial potentials be ignored.
对于一根孤立的、活跃的、可兴奋纤维，其电源强度可以非常近似地看作是它的跨膜电流。跨膜电流只能从细胞内电位来确定。但是对于多细胞制剂，特别是心室肌，间质电位场的存在可能会显著改变电源强度。本报告研究了间质电位场的大小与深入被视为合胞体的心肌半无限组织结构深度的函数关系。假设存在一个均匀传播的平面激发波，并基于将介质视为连续体（双域模型）来找到间质电位场。总体而言，结果与通常用于表示容积导体的任何极限情况均不一致，并表明只有在最薄的组织（小于200微米）中，间质电位才可以忽略不计。
