Effects of alcohol on ion transport by isolated gastric and esophageal mucosa.

The effects of ethyl alcohol, 20%, were measured on steady state rates of ion transport by isolated mucosa. Luminal, but not serosal, addition of alcohol altered ion transport. Alcohol caused a sustained reduction in apparent basal acid secretion by fundic mucosa. These tissues were resistant to ordinarily effective stimulants of acid secretion (histamine, theophyline, dibutyryl cyclic AMP, and gastrin) by rabbit mucosa. Across antral mucosa, net Na transport was inhibited, and net Cl transport was reduced in the presence of alcohol. The unidirectional fluxes of both ions were increased as was permeability to erythritol. These effects of alcohol did not require the presence of acid in the lumen. The rate of luminal acid loss by antrum was increased by alcohol. Addition of ouabain alone, which inhibits net Na and Cl transport, did not alter the rate of luminal acid loss by antrum. Alcohol, however, still increased the rate of luminal acid loss by antral mucosa treated with ouabain. Alcohol reduced the electrical resistance of fundic and antral mucosa but had no effect on the rate of luminal acid loss or electrical resistance of esophageal mucosa. Luminal application of alcohol inhibits active ion transport in addition to increasing cation and anion permeability. However, inhibition of active transport per se is not necessarily associated with an increase in mucosal permeability.