The effect of misoprostol on base-line and stimulated acid secretion and on gastrin and histamine release in the totally isolated, vascularly perfused rat stomach.

The effects of the prostaglandin E1 analogue misoprostol on base-line and stimulated (gastrin, histamine, and the muscarinic M1 agonist McN-A-343) acid secretion, base-line and gastrin-stimulated histamine release, and base-line and McN-A-343-stimulated gastrin release in the totally isolated, vascularly perfused rat stomach were studied. At a concentration of 1 nM, misoprostol significantly (p less than 0.01) inhibited base-line acid secretion from 13.7 +/- 2.7 to 4.8 +/- 0.7 mumol/60 min, histamine-stimulated acid secretion from 99.9 +/- 15.1 to 21.8 +/- 8.2 mumol/60 min, maximal gastrin-stimulated secretion from 92.5 +/- 11.4 to 3.1 +/- 0.6 mumol/60 min, and maximal McN-A-343-stimulated secretion from 60.0 +/- 8.9 to 6.8 +/- 2.6 mumol/60 min (mean +/- SEM). Likewise, misoprostol significantly inhibited base-line vascular histamine release (p less than 0.05) from 10.1 +/- 2.3 to 3.7 +/- 0.7 nmol/60 min and gastrin-stimulated release (p less than 0.01) from 54.7 +/- 7.9 to 20.2 +/- 4.1 nmol/60 min (mean +/- SEM). The gastrin release was not affected by misoprostol. We conclude that misoprostol inhibits acid secretion both by a direct effect on the parietal cell and by inhibiting endogenous histamine release.