A variety of techniques of cell capacitance measurement have been proposed and applied in cellular electrophysiology. They are mostly based on the evaluation of membrane current responses to small changes in the membrane voltage. One of the currently used approaches applies the least-squares fit of an exponential current decay in response to voltage clamped rectangular pulses. In this study, we propose an alternative simpler approach to evaluation of the exponential parts in the current responses to square wave stimulation and present preliminary results of membrane capacitance evaluation. It is based on the property of the exponential function that has not yet been used to measure membrane capacitance. The time constant and the asymptote of the exponential waveform are unambiguously determined by the values read at three points separated by a constant time interval. In order to minimize the effect of noise and deviations from the exponential waveform, the triplet of points is designed to slide along the time axis. The results of the proposed approach and those previously evaluated by the least squares method are comparable. The method described may be advantageous for continuously recording changes in membrane capacitance.

已经提出了多种细胞电容测量技术，并将其应用于细胞电生理学中。它们主要基于对膜电压微小变化的膜电流响应的评估。当前使用的方法之一是响应于电压钳制矩形脉冲而应用指数电流衰减的最小二乘拟合。在这项研究中，我们提出了另一种更简单的方法来评估方波刺激电流响应中的指数部分，并提出了膜电容评估的初步结果。它基于尚未用于测量膜电容的指数函数的属性。指数波形的时间常数和渐近线明确地由在以恒定时间间隔分隔的三个点处读取的值确定。为了最小化噪声和与指数波形的偏差的影响，点的三元组设计为沿时间轴滑动。所提出的方法的结果与先前通过最小二乘法评估的结果是可比的。所描述的方法对于连续记录膜电容的变化可能是有利的。