Inhibition of active transport of chloride and sodium by vanadate in the cornea.

Vanadate, an inhibitor of (Na+ + K+)ATPase, also inhibits active transepithelial Na+ and Cl- transport (measured as short-circuit current) in the isolated cornea in concentrations of 10(-4)M to 10(-3)M. The disulfonic stilbene, DIDS, does not affect the short-circuit current per se, but it prevents the inhibitory effect of vanadate on Na+ and Cl- transport. Since vanadate acts in other systems from the cytoplasmic side, it is postulated that DIDS interferes with vanadate penetration into the epithelial cells. These results also strengthen the notion of a Na-Cl co-transport system in the corneal epithelium.