Tests of continuum theories as models of ion channels. II. Poisson-Nernst-Planck theory versus Brownian dynamics
Tests of continuum theories as models of ion channels. II. Poisson-Nernst-Planck theory versus Brownian dynamics
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DOI：
10.1016/s0006-3495(00)76781-6
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发表时间：
2000-05-01
影响因子：
3.4
通讯作者：
Chung, SH
中科院分区：
文献类型：
--
作者：
Corry, B;Kuyucak, S;Chung, SH
我们测试的平均场近似的有效性泊松-能斯特-普朗克理论通过对比其预测与布朗动力学模拟在示意性的圆柱形通道，并在一个现实的钾通道。在对照研究中证明了这两种理论在散装情况下的等效性。在简单的圆柱形通道中，这两种理论在通道中的浓度分布及其电导特性方面存在很大差异。这些差异在半径小于德拜长度的窄通道中最大，并随着半径的增加而减小。当沟道半径超过2德拜长度时，会发生收敛。这些测试明确地表明，泊松-能斯特-普朗克理论中的平均场近似在半径小于德拜长度的窄离子通道中失效。
We test the validity of the mean-field approximation in Poisson-Nernst-Planck theory by contrasting its predictions with those of Brownian dynamics simulations in schematic cylindrical channels and in a realistic potassium channel. Equivalence of the two theories in bulk situations is demonstrated in a control study. In simple cylindrical channels, considerable differences are found between the two theories with regard to the concentration profiles in the channel and its conductance properties. These differences are at a maximum in narrow channels with a radius smaller than the Debye length and diminish with increasing radius. Convergence occurs when the channel radius is over 2 Debye lengths. These tests unequivocally demonstrate that the mean-field approximation in the Poisson-Nernst-Planck theory breaks down in narrow ion channels that have radii smaller than the Debye length.