AJP - Gastrointestinal and Liver Physiology, Vol 254, Issue 4 531-G537, Copyright © 1988 by American Physiological Society

ARTICLES

Somatostatin inhibition of secretagogue and forskolin-stimulated gastric acid secretion

F. Michelangeli, M. C. Ruiz, C. L. Rodriguez and A. Pelacca
Laboratorio de Fisiologia Gastro-Intestinal, Instituto Venezolano de Investigaciones Cientificas, Caracas, Venezuela.

The action of somatostatin (SS) on acid secretion and histamine release was studied in isolated gastric mucosa of toads mounted in Ussing chambers. SS inhibited H+ secretion and histamine release stimulated by cholinergic and gastrinergic secretagogues. Exogenous histamine stimulation of H+ secretion was blocked noncompetitively by SS in a dose-dependent manner. In mucosae maximally stimulated by histamine or forskolin and cimetidine, acetylcholine (ACh) and tetragastrin (TG) induced a direct stimulation of the oxyntopeptic cell not inhibited by SS. Indomethacin, an inhibitor of prostaglandin synthesis, did not prevent SS inhibition of histamine stimulation. Pretreatment with SS abolished forskolin stimulation of H+ secretion. SS induced a small inhibition of the stimulatory effect of N6, 2'-O-dibutyryladenosine 3',5'-cyclic monophosphate. These results suggest that SS inhibits acid secretion stimulated by secretagogues through different mechanisms: 1) inhibition of histamine release by ACh and TG, 2) inhibition of endogenous and exogenous histamine stimulation through a blockade of adenylate cyclase, and 3) an inhibitory effect subsequent to the synthesis of adenosine 3',5'-cyclic monophosphate. The direct activation of the oxyntopeptic cell by ACh and TG does not seem to be affected by somatostatin.

This article has been cited by other articles:

				K. Aurang, J. Wang, and K. C. K. Lloyd Somatostatin Inhibition of Acid and Histamine Release by Activation of Somatostatin Receptor Subtype 2 Receptors in Rats J. Pharmacol. Exp. Ther., April 1, 1997; 281(1): 245 - 252. [Abstract] [Full Text]