Effect of silver chloride on the short-circuit current across the isolated toad skin.

Since addition of 10^?4M AgNO₃ to either an inside or outside bathing medium containing sulfate had no effect on short-circuit current (SCC), a measure of net Na⁺ transport, or transmural potential difference (PD) in the isolated surviving toadskin, the effect of adding Ag⁺ to chloridebased Ringer solution was studied. Exposure of the outside bathing medium to 10^?4M AgNO₃ resulted in, after a 20 minute time lag, a 250 ± 51% (N=6) increase in SCC within 100 minutes as opposed to an immediate response which had a 350 ± 26% (N=8) increase in SCC by addition of 10^?4M AgNO₃ to the inside bathing solution. The dose response curve relating change in SCC to the Ag⁺ concentration added to the inside bathing medium was saturable at 10^?5M Ag⁺. The uptake of Ag⁺ by the tissue, as measured by atomic absorption spectrophotometry, showed no correlation to the relative change in SCC. Na⁺ flux experiments under short-circuited conditions showed that Ag⁺Cl^? stimulated only the unidirectional outside to inside Na⁺ flux. These results indicate that Ag⁺Cl^? enhances active sodium transport and that Ag⁺Cl^? binding to specific membrane groups is required for this effect.