Biophysical Journal 9: 1029-1044 (1969)
© 1969 the Biophysical Society

This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Takeguchi, N. Articles by Nakagaki, M. Search for Related Content PubMed PubMed Citation Articles by Takeguchi, N. Articles by Nakagaki, M.

Concentration Dependence of Permeability Coefficients to an Electrolyte Component across Bovine Lens Capsule In Vitro

ABSTRACT

Theoretical and experimental studies have been made on permeability coefficients to various kinds of electrolyte across lens capsules that are dissected from bovine eyes and that are found to be positively fixed charged membranes from our experiments of membrane potentials. The differential permeability coefficient, P_m, is defined as J_s = P_m(C₂ - C₁), where J_s is the flux of an electrolyte component in moles per sec across unit area of the lens capsule that separates two aqueous solutions of the same electrolyte at different concentrations, C₂ and C₁. Various types of strong electrolytes were studied; KCl, NaCl, Cacl₂, MgSO₄, MgCl₂ and LaCl₃. It was found that at C₂/C₁ = constant, P_m decreases to zero as C₂ decreases and P_m increases to a limiting value, (P_m), that is characteristic for the system of the salt used and the membrane as C₂ increases, despite of electrolytes. We assumed in theory that single ion activity coefficients of co-ion and gegen-ion are ideal, that the systems studied are in electric neutrality, that the fixed charge density of the membrane is independent of concentrations C₂, and that Donnan equilibrium holds between the bulk solution and membrane surface. Although the concentration-dependent changes of P_m were quantitatively different depending on the type of electrolyte used, general agreement between theory and experiment was obtained over a wide range of concentrations except for the case of very dilute solutions.