Calculation of Na +/Cl ? Selectivity in Tight Junctions between Epithelial Cells by Methods of Nonlocal Electrostatics with Pole Models of Dielectric Function without an Overscreening Effect

摘要

A mathematical model of Na_(+)/Cl_(?)selectivity in tight junctions (TJs) between epithelial cells was developed. It was demonstrated that Na_(+)/Cl_(?)selectivity in TJs depends on the total charge of amino-acid residues of claudin macromolecules within TJs, as well as on the ion-distribution coefficients between TJs and free solution. It was demonstrated that the obtained formulas predict a change of Na_(+)/Cl_(?)selectivity in TJs for Cl_(?)/Na_(+)selectivity if the sign of the total charge of amino-acid residues in TJ changes. The calculated Na_(+)/Cl_(?)selectivity value for MDCK cells coincides with the experimental data of (Colegio et al., 2002). To calculate a change in ion-solvation energy during their transition to TJs, formulas for nonlocal electrostatics with one-, two-, and three-pole models of dielectric function without taking into account the overscreening effect were used.