AJP - Gastrointestinal and Liver Physiology, Vol 268, Issue 1 102-G106, Copyright © 1995 by American Physiological Society

ARTICLES

Activation of somatostatin receptor subtype 2 inhibits acid secretion in rats

K. C. Lloyd, J. Wang, K. Aurang, P. Gronhed, D. H. Coy and J. H. Walsh
Research Services, Department of Veterans Affairs, West Los Angeles Medical Center, California.

Somatostatin is a potent inhibitor of gastric acid secretion. Recently, at least five distinct somatostatin receptor subtypes (SSTR) have been characterized and evaluated using relatively selective peptide analogues of somatostatin. We sought to determine which somatostatin receptor subtypes are involved in peripheral regulation of gastric acid secretion. Fasted, male Sprague-Dawley rats were anesthetized and were implanted with a double-lumen cannula in the stomach. Acid secretion was measured in gastric samples collected every 10 min by backtitration to pH 7. After a 30-min basal period, a 2-h intravenous infusion of pentagastrin (24 micrograms.kg-1.h-1 i.v.) was started. During the second pentagastrin hour, a 1-h intravenous infusion of either vehicle (0.1% canine serum albumin in 0.9% saline) or somatostatin receptor agonists was begun. The somatostatin receptor agonists included peptides with relative specificity for SSTR1-5 (somatostatin-14; 10 nmol.kg-1.h-1); SSTR2, SSTR3, and SSTR5 [SMS-(201-995); 10 nmol.kg-1.h-1]; SSTR2 (1-1,000 nmol.kg-1.h-1); SSTR3 (10-1,000 nmol.kg-1.h-1); and SSTR5 (10-1,000 nmol.kg-1.h-1). The SSTR2 agonist decreased pentagastrin-stimulated acid secretion dose dependently, from 82 +/- 7% of maximum acid output at 1 nmol.kg-1.h-1 to 4 +/- 7% of maximum at 100 nmol.kg-1.h-1. At 10 nmol.kg-1.h-1, the SSTR2 agonist inhibited acid secretion (40 +/- 7% of maximum) similarly to somatostatin (37 +/- 4% of maximum) and SMS-(201-995) (31 +/- 4% of maximum). The SSTR2 agonist inhibited acid secretion approximately 10- to 100-fold more potently than either the SSTR3 or the SSTR5 agonist. These results indicate that somatostatin regulates gastric acid secretion by activation of SSTR2 receptors.

This article has been cited by other articles:

				C. Chisholm and G. R. Greenberg Somatostatin receptor subtype-5 mediates inhibition of peptide YY secretion from rat intestinal cultures Am J Physiol Gastrointest Liver Physiol, November 1, 2000; 279(5): G983 - G989. [Abstract] [Full Text] [PDF]

				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]