Physiological significance of ECL-cell histamine

In the oxyntic mucosa of the mammalian stomach, histamine is stored in ECL cells and in mucosal mast cells. In the rat, at least 80 percent of oxyntic mucosal histamine resides in the ECL cells. Histamine is a key factor in t he regulation of gastric acid secretion. Following depletion of ECL-cell hi stamine by treatment with alpha-fluoromethylhistidine (alpha-FMH), basal ac id secretion was reduced, and gastrin-stimulated acid secretion was abolish ed. Vagally-induced acid secretion (by insulin injection or pylorus ligatio n) was unaffected by alpha-FMH treatment but inhibited by an H-2 antagonist . These results suggest that gastrin stimulates acid secretion via release of ECL-cell histamine, whereas vagally-induced acid secretion-although hist amine-dependent-does not rely on ECL-cell histamine. Gastrin is known to ha ve a trophic effect on the oxyntic mucosa. By combining long-term hypergast rinemia with continuous infusion of alpha-FMH, we were able to show that ga strin-evoked trophic effects in the stomach do not depend on ECL-cell hista mine.