Ontogeny of Gastric Acid Secretion in the Rat: Evidence for Multiple Response Systems

Gastric acid secretion has been thought to depend on histamine stimulation of the parietal cell. However, in the 2-week-old rat neither exogenous histamine nor the H-2 receptor agonist impromidine stimulates acid secretion, whereas pentagastrin and the cholinergic agent bethanechol are potent stimuli. At this age, the effect of pentagastrin on acid secretion is not blocked by the H-2 receptor antagonist cimetidine, nor is it potentiated by impromidine. These data suggest that, in the rat pup, the acid secretory response to pentagastrin and cholinergic agents occurs before the histamine-mediated system is functional and operates independently of the actions of histamine.