Computing numerically the access resistance of a pore
Computing numerically the access resistance of a pore
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DOI：
10.1007/s00249-004-0452-x
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发表时间：
2005-06-01
影响因子：
2
通讯作者：
Eisenberg, RS
中科院分区：
文献类型：
--
作者：
Aguilella-Arzo, M;Aguilella, VM;Eisenberg, RS
通道的进入电阻（AR）是离子通道的电导的重要组成部分，特别是在宽通道和短通道中，其中它占离子移动的总电阻的相当大的一部分。AR通常通过使用霍尔从静电学（J.E. Hall 1975 J.Gen.Phys.66：531-532），尽管已经提出了其他表达式，包括解析表达式和数值表达式。在这里，我们报告了一些数值结果的AR的通道通过求解Poisson-Nernst-Planck方程的入口处的圆形孔隙。协议之间的数值计算和分析结果霍尔方程中性膜中不带电的孔。然而，对于嵌入带电膜中的通道，Hall的表达高估了AR，AR要低得多，在某些情况下甚至可以忽略不计。在低盐浓度下，AR对带电膜的孔半径的弱依赖性可以用来分离通道和接入对测量的电导的贡献。
The access resistance (AR) of a channel is an important component of the conductance of ion channels, particularly in wide and short channels, where it accounts for a substantial fraction of the total resistance to the movement of ions. The AR is usually calculated by using a classical and simple expression derived by Hall from electrostatics (J.E. Hall 1975 J. Gen. Phys. 66:531-532), though other expressions, both analytical and numerical, have been proposed. Here we report some numerical results for the AR of a channel obtained by solving the Poisson-Nernst-Planck equations at the entrance of a circular pore. Agreement is found between numerical calculations and analytical results from Hall's equation for uncharged pores in neutral membranes. However, for channels embedded in charged membranes, Hall's expression overestimates the AR, which is much lower and can even be neglected in some cases. The weak dependence of AR on the pore radius for charged membranes at low salt concentration can be exploited to separate the channel and the access contributions to the measured conductance.