Metabolic inhibitors reversibly alter the basal membrane potential of the Gecko retinal pigment epithelium

The effects of metabolic inhibitors on the apical and basal membrane potentials were studied in the isolated retinal pigment epithelium of the lizard Gekko gekko. Adding dinitrophenol or cyanide or cooling the tissue to 15°C first depolarized the apical membrane and then hyperpolarized the basal membrane. The basal hyperpolarization was accompanied by an apparent increase in basal resistance. These effects were fully reversible. Adding ouabain to inhibit specifically the apical Na+-K * pump irreversibly depolarized the apical membrane but did not produce a basal membrane hyperpolarization. Dinitrophenol. cyanide and azide also reversibly inhibited a basal membrane response that was evoked by changing the apical potassium concentration, Ouabain did not inhibit this potassium-evoked basal response. These results suggest hat metabolic inhibitors will be useful tools to study RPE basal membrane function