Salicylate Effects on Proton Gradient Dissipation by Isolated Gastric Mucosal Surface Cells1

The effects of salicylate were examined on Na⁺/H⁺ exchange by isolated gastric mucosal surface cells loaded with H⁺ and resuspended in a buffered medium. Choline salicylate (pH 7.4) increases the dissipation of an intracellular proton gradient which was measured using acridine orange. The exchange of extracellular Na⁺ with intracellular H⁺ by surface cells not only remains intact but also is enhanced upon exposure to salicylate. This was confirmed by cellular uptake of ²²Na and titration of cellular H⁺ efflux. Salicylate increases Na⁺/H⁺ exchange via a pathway predominantly sensitive to amiloride. However, the data also suggest that salicylate dissipates an intracellular proton gradient by an additional mechanism. The latter is independent of extracellular Na⁺ and not due to a generalized increase in cellular permeability.