INDEPENDENCE OF NAK PUMP ACTIVITY AND BASOLATERAL MEMBRANE CONDUCTANCE IN BULLFROG CORNEAL EPITHELIUM

1. The effects of inhibition of the Na:K pump on membrane conductances in the isolated bullfrog corneal epithelium were assessed on the basi s of measurements of DC and AC electrical parameters in conjunction wi th morphological analyses. 2. Inhibition of the Na:K pump by either 0. 1 mM ouabain or 5 mM BaCl2 increased the epithelial thickness and cons tricted the intercellular spaces. Initially, ouabain did not change ei ther the apical or basolateral membrane conductance whereas barium sel ectively decreased the latter by 35%. 3. Therefore, a decrease in Na:K pump activity has no direct effect on membrane conductance. Neverthel ess, its activity is linked to cell volume maintenance.