Electrical characteristics of sphingomyelin bilayer membranes.

Current-voltage characteristics and the conductivity temperature dependence of sphingomyelin bilayer membranes have been determined. The resistances were of the order of 10(8) Omega-cm(2) and exhibited ohmic behavior up to approximately 25 mv followed by increasing conductivity with applied voltage. The current is found to be proportional to a hyperbolic sine function of the voltage. The temperature dependence indicates a thermally activated conduction mechanism. The observed behavior closely follows a kinetic model involving a barrier modified by the applied electric field, the rate-limiting process being the surmounting of the barrier by the impinging ions. The model allows predictions to be made over a wide range of conditions.