A barrier model for current flow in lipid bilayer membranes

Abstract

Theshape of the energy barrier inside thin, insulating membranes can be an important factor in determining the detailed behavior of transmembrane ionic flows. In particular, a model is developed in which the shape of the barrier is expected to have direct influence on such experimentally important membrane properties as: (a) the shape of the current-voltage relation; (b) the dependence of zero current conductivity on asymmetric concentrations; (c) the dependence of the rectification ratio on the concentration ratio. Current-voltage curves were measured for a wide range of symmetrical and asymmetrical concentrations in black lipid (phosphatidyl ethanolamine) films in the presence of nonactin and potassium. A single barrier shape was found to describe accurately the experimental results in terms of the model.