Effect of silver ion on permeability properties of frog skin

Abstract

Ag⁺ added to the external bathing solution of frog skin causes a marked decrease in potential difference and an increase in conductance. Short-circuit current and net Na⁺ flux decrease somewhat. Na⁺ outflux and fluxes of $\text{SO}{}_4{}^{\mathrm{2-}}$ and mannitol are increased by Ag⁺. The fluxes of these solutes initially increase to 10–15 times control levels and then spontaneously decline to approximately 3 times control levels. These changes appear to be due to alteration of a shunt pathway in the skin. In addition, studies of washout of ²⁴Na⁺ and ⁴²K⁺ indicate that Ag⁺ effects the cation selectivity of the outer barrier; movement of K⁺ across this barrier increases markedly with minimal change in Na⁺ movement.