ADENOSINE - A MODULATOR OF GASTRIC-ACID SECRETION INVIVO

  • 1 January 1984
    • journal article
    • research article
    • Vol. 231  (1) , 109-113
Abstract
The hypothesis that there are adenosine receptors in the gastric fundus responsible for the modulation of acid secretion to secretagogues was tested. Anesthetized gastric fistula dogs were used as subjects and both the secretagogues (histamine, 0.5 .mu.g/min and methacholine, 1 .mu.g/min) and adenosine were infused through the gastric artery supplying the fundus of the stomach to avoid systemic effects of the drug. Adenosine infused to a concentration of 30 .mu.M inhibited histamine-stimulated acid secretion from 197 .+-. 25 to 68 .+-. 19 .mu.eq/15 min and inhibited methacholine-stimulated acid secretion from 280 .+-. 48 to 81 .+-. 24 .mu.eq/15 min. Theophylline infused i.v. to a plasma concentration of 17 .mu.g/ml (94 .mu.M) blocked the inhibitory effect of adenosine on gastric acid secretion but did not affect the inhibitory effect of prostaglandin E2 on gastric acid secretion. The specific phosphodiesterase inhibitor RO 20 1724 [4-(3-butoxy-4-methoxybenzyl)-2-imidazolidinone] did not alter the inhibitory effect of adenosine on gastric acid secretion. In addition to its effect on gastric acid secretion, adenosine was a potent vasodilator of gastric blood vessels. Apparently, there are inhibitory adenosine R receptors in the gastric fundus that modulate acid secretion to both histamine and methacholine.