Tests of continuum theories as models of ion channels. II. Poisson- Nernst-Planck theory versus brownian dynamics

Ben Corry, Serdar Kuyucak, Shin Ho Chung*

*Corresponding author for this work

    Research output: Contribution to journalArticlepeer-review

    286 Citations (Scopus)

    Abstract

    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.

    Original languageEnglish
    Pages (from-to)2364-2381
    Number of pages18
    JournalBiophysical Journal
    Volume78
    Issue number5
    DOIs
    Publication statusPublished - 2000

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