The effect of prostaglandins on gastric parietal and non-parietal secretion in the anaesthetized rat

Abstract

The effects of prostaglandin E2 (PGE2), 16,16-dimethyl prostaglandin E2 (dmPGE2) and prostaglandin F2 alpha (PGF2 alpha) on gastric secretion have been examined in the anaesthetized rat. The prostaglandins stimulated the secretion of a non-parietal juice which was rich in Na+ and Cl- with smaller amounts of K+ and HCO3-. Doses of the prostaglandins that stimulated gastric non-parietal secretion also inhibited histamine stimulated gastric acid secretion, and thus the same rank order of potency was obtained for the prostaglandins on the two secretory mechanisms, viz. dmPGE2 greater than PGE2 greater than PGF2 alpha. During the secretion of endogenous gastric acid the secretagogue effect of the prostaglandins on non-parietal secretion was diminished, and this effect appeared to be due to the presence of intraluminal acid since it was mimicked by application of exogenous HCl to the gastric mucosal surface. Thus, the present results show that prostaglandins affect both the parietal and non-parietal secretions in the rat stomach and that these mechanisms show some interdependence.

Characteristics of the muscularis mucosae in the acid-secreting region of the rabbit stomach

“…First, several endogenous agents that modulate acid secretion, including CCK (17,36), gastrin (32), secretin (13), somatostatin (37), and adenosine (34,46), were without a measurable effect on muscularis mucosae from either region of the gastric corpus. Second, PGE 2 and PGF 2␣ , substances that are capable of inhibiting acid secretion (4,32), contracted fundic muscularis mucosae while eliciting trivial responses in antral preparations. Third, throughout the acid-secreting region of the stomach the predominant response of the muscularis mucosae to stimulation of its intrinsic innervation was a pronounced relaxation.…”