Time course of pump inhibition by ouabain in amphibian epithelia.

Inhibition by ouabain of rheogenic Na+ transport across the basolateral membranes of frog skin is found to be manifest within 3-4 min. This rate of pump inhibition is not different from the rate of diffusion through extracellular tissue layers between the serosal bath and the actual site of action, i.e., the epithelial cell layers. It is concluded that the well-known slow time course of decrease in transepithelial current flow is due to ionic redistribution and conductance changes of the epithelial membranes secondary to pump inhibition.