Relations between hydrochloric acid secretion and electrical phenomena in frog gastric mucosa

Abstract

The potential difference (p.d.), resistance, electrical power production and rate of acid secretion of isolated frog gastric mucosa were measured with an apparatus which is descr. The secretory side of frog gastric mucosa was negative with respect to the nutrient side in an external circuit. During acid secretion the p.d. was decreased and the resistance increased. Anaerobically the resistance increased and both p.d. and acid secretion were abolished. The mean p.d. across mucosa from the corpus of the stomach was -30 mv.; rectal mucosa -16mv; pyloric mucosa -5mv; esophageal, duodenal and ileal mucosa -2mv. The rise of p.d. after mounting the gastric mucosa was probably caused by the decay of injury potentials. Expts. suggest that the fall in p.d. on secretion was not due to diffusion potentials between the solns. bathing the mucosa. Unstimulated frog gastric mucosae could send a current round an external circuit, producing a maintained electrical power output of the order of 1[mu]w./mg. dry wt. without appreciable polarization. About 10% of the metabolic energy was thereby canalized into electrical energy. This is taken to support the theory that secreting mucosae produce HC1 by an electrochemical mechanism. Based on the foregoing and other results, an electron-cycle mechanism of acid secretion is suggested, in which H atom and electron transport systems are coupled to produce a net separation of H and OH ions in the pericanalicular zone of the oxyntic cells. The energy required is obtained from aerobic metabolism.