Effects of amphotericin B on ionic transport and sodium permeability of the toad lens.

The polyene antibiotic amphotericin B decreases the PD and short-circuit current (SCC) across the amphibian lens in vitro. It was only effective when placed in the solution at the anterior side and its effect was reversible. Amphotericin B caused a large decline in the PD across the anterior surface of the lens and a smaller reduction in the PD across the posterior side. This seems to be due to a direct decrease of the electrical resistance of the anterior face. The effects required the presence of sodium in the Ringer solution bathing the anterior surface. The translenticular Na fluxes were increased in both directions so that the net flux changed little. Amphotericin B produced a considerable increase in the rate of accumulation of sodium and loss of potassium by the lens. The oxygen consumption of the lens was unchanged by amphotericin B. Amphotericin B appears to act on the lens epithelium by selectively increasing its passive sodium permeability.