Misakian M, Kasianowicz J J, Robertson B, Petersons O
NIST, Electricity Division, Gaithersburg, Maryland 20899-8113, USA.
Bioelectromagnetics. 2001 Oct;22(7):487-93. doi: 10.1002/bem.77.abs.
Alternating currents were measured through transmembrane ion channels formed by Staphylococcus aureus alpha-hemolysin proteins in planar bilayer membranes as part of an investigation to determine the channel's frequency response and the appropriateness of an equivalent circuit commonly used to model electrical interactions at the surface of cells. The experimental approach includes a novel method for separating the alternating current through one or more channels, which is conductive in nature, from the capacitively coupled current through the membrane. Separation of the conductive and capacitive alternating currents made it possible to measure the frequency response of the alpha-hemolysin channels. The results of the study are consistent with an equivalent circuit of a membrane capacitor in parallel with one or more channel resistors over the frequency range 30-120 Hz. The possible usefulness of frequency response data for ion channels in cell membranes during investigations of biological effects of time-varying magnetic fields is briefly discussed.
作为确定通道频率响应以及常用于模拟细胞表面电相互作用的等效电路是否合适的研究的一部分，通过平面双层膜中由金黄色葡萄球菌α-溶血素蛋白形成的跨膜离子通道测量了交流电。实验方法包括一种新颖的方法，用于将本质上具有导电性的通过一个或多个通道的交流电与通过膜的电容耦合电流分离。传导性和电容性交流电的分离使得测量α-溶血素通道的频率响应成为可能。该研究结果与在30 - 120 Hz频率范围内与一个或多个通道电阻并联的膜电容器的等效电路一致。还简要讨论了在研究时变磁场的生物效应期间，离子通道频率响应数据在细胞膜中的可能用途。
