Gastric secretion: mechanism for production of hydrogen ions.

The passage of a direct electric current across a fixed-charge membrane interposed between neutral electrolyte solutions can give rise to the production of hydrogen and hydroxide ions at the solution-membrane boundary in equivalent amounts, each of which can approach and equal the number of faradays passed. At this unique boundary, the electric field can inhibit the rate of recombination of hydrogen and hydroxide ions strongly enough to increase the dissociation constant of water and other weak electrolytes by several orders of magnitude. These observations lead to a model of the gastric secretory process wherein the gastric potential, primarily due to the activity of a chloride-ion pump, is applied across an adjacent ionselective membrane also present in the mucosa. The dissociating weak electrolyte can be water, to produce hydrogen ions in the stomach and hydroxide ions which combine with carbon dioxide in the blood, or it can be carbonic acid to produce bicarbonate directly.