The reduction of gastric acidity by back-diffusion by hydrogen ions through the mucosa.

It is generally believed that the hydrochloric acid solution secreted by the oxyntic cells is isotonic with the blood, and that the reduction of the acidity observed in the gastric juice is due to subsequent dilution and neutralization by other secretions (see Babkin, 1944). Teorell (1933), using anaesthetized or decerebrate cats whose stomachs were tied at both ends, observed a rapid decrease in the acidity of hydrochloric acidsolutions injected into the stomach, without a corresponding reduction of the volume of the injected iluid. From these results, andfrommodel experiments with artificial membranes, he inferred that the reduction of the acidity of the gastric juice was due mainly to the diffusion of H+ ions through the gastric mucosa into the blood. However, diffusion of H+ ions through living gastric mucosa has not so far been demonstrated, and this paper describes an attempt to investigate the diffusion of H+ ions through isolated amphibian gastric mucosa. The results show that H+ ions can diffuse through surviving mucosa and that the rates of diffusion are linearly related to the H+ ion concentration of the solution in contact with the secretory side of the tissue (see Teorell, 1933, 1939).