Neurogenic stimulation of gastric acid secretion by the Na+, K(+)-ATPase inhibitor ouabain in mouse isolated stomach.

1. We have previously found the stimulatory effect of ouabain on gastric acid secretion. In the present study, we further studied the ouabain-induced acid secretion in mouse isolated stomach. 2. In the resting stomach preparation, ouabain produced a transient increase in basal acid secretion, which was followed by a fall to the level lower than the initial basal level. 3. The ouabain-induced acid secretion was abolished by tetrodotoxin or atropine, and was partially inhibited by hexamethonium or famotidine. High K+ solution potentiated the ouabain stimulation. 4. Endogenous ouabain has been recently identified in plasma of humans, but the physiological roles of this compound have not yet been defined. The present study in mouse isolated stomach showed that ouabain induced a transient increase in gastric acid secretion through the release of endogeneous acetyl-choline, and subsequently inhibited acid secretion. It therefore seems likely that endogeneous ouabain modifies gastric acid secretion in physiological and pathological conditions.