Hempling H G
Department of Physiology, Medical University of South Carolina, Charleston 29425.
J Membr Biol. 1989 Sep;110(2):127-37. doi: 10.1007/BF01869468.
This paper describes computer programs which may be used to identify and analyze cation and anion channels. Weak acids are used to increase intracellular proton concentrations and by so doing to promote the exchange of osmotically active cations with protons. The time course of cation exchange is readily identified from the changes in cell volume which accompany the net changes in osmotically active cations. Weak bases are used to identify and analyze hydroxyl/anion exchange by a comparable strategy. The model was able to produce data that agreed with experimental data in the literature with an accuracy equal to experimental error. One program, called PROPIONATE, uses the weak acid, propionic acid, to identify cation channels such as the sodium-proton exchanger or the calcium-dependent, potassium channel. A second program, called BASE, is more general because either a weak acid such as propionic acid or a weak base such as ammonia may be used individually or together. When experimental data are available, the programs may be used to calculate permeability coefficients for ion channels and the capacity of intracellular buffers. The programs may be used also in the design of experiments. Initial values may be assigned to intracellular and extracellular electrolyte and proton concentrations. Values for intracellular buffer capacity and channel permeabilities may be chosen. The program will then generate changes in ions, cell volume, and intracellular pH when either a weak acid, a weak base or combination of the two is added to the external medium.
本文描述了可用于识别和分析阳离子和阴离子通道的计算机程序。弱酸用于增加细胞内质子浓度，从而促进渗透活性阳离子与质子的交换。阳离子交换的时间进程可根据伴随渗透活性阳离子净变化的细胞体积变化轻易识别。弱碱用于通过类似策略识别和分析羟基/阴离子交换。该模型能够产生与文献中的实验数据相符的数据，其准确性等同于实验误差。一个名为PROPIONATE的程序使用弱酸丙酸来识别阳离子通道，如钠-质子交换器或钙依赖性钾通道。另一个名为BASE的程序更通用，因为可以单独或一起使用弱酸（如丙酸）或弱碱（如氨）。当有实验数据时，这些程序可用于计算离子通道的渗透系数和细胞内缓冲剂的容量。这些程序也可用于实验设计。可以为细胞内和细胞外电解质及质子浓度指定初始值。可以选择细胞内缓冲容量和通道渗透率的值。然后，当向外部介质中添加弱酸、弱碱或两者的组合时，该程序将生成离子、细胞体积和细胞内pH值的变化。
