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J Gastroenterol (2009) 44:396404 DOI 10.1007/s00535-009-0018-x
ORIGINAL ARTICLEALIMENTARY TRACT
The effect and mechanism of action of capsaicin on gastric acid output
Kazuhiro Imatake Teruaki Matsui Mitsuhiko Moriyama
Received: 21 September 2007 / Accepted: 10 November 2008 / Published online: 19 March 2009 Springer 2009
AbstractBackground Capsaicin has benecial pharmacological properties, such as the ability to improve appetite and digestion. However, capsaicin has been reported to suppress gastric acid output, but to increase secretion; no consensus as to its effects on gastric acid output has been reached, and the underlying mechanisms remain to be elucidated.
Methods Rat gastric lumen was perfused with capsaicin. Basal acid output and gastric acid secretion stimulated by vagal nerve activation and bethanecol, a muscarinic receptor agonist, were measured. After intravenous infusion of calcitonin gene-related peptide (CGRP), the measurements were repeated. The secretion of gastrin, somatostatin, and histamine was measured in isolated vascularly perfused rat stomach after vagal nerve and bethanecol stimulation, and under the inuence of capsaicin.
Results Capsaicin administration had no effect on basal gastric acid output, but inhibited acid secretion resulting from vagal stimulation. Capsaicin had no effect on acid secretion resulting from stimulation with bethanecol. Administration of high-dose CGRP inhibited basal acid output and gastric acid secretion from both vagal nerve and bethanecol stimulation. Low-dose CGRP inhibited gastric acid secretion because of vagal stimulation, but had no effect on basal secretion or acid secretion following stimulation with bethanecol. Capsaicin administration inhibited
the stimulated gastrin and histamine secretion and reversed the suppression of somatostatin secretion mediated by vagal stimulation. However, capsaicin had no effect on stimulated gastrin secretion, suppression of somatostatin secretion, or stimulated histamine secretion because of bethanecol.
Conclusions Capsaicin inhibited gastric acid output, and the mechanism underlying this effect appears to involve vagal nerve inactivation.
Keywords Capsaicin Gastric acid output Calcitonin
gene-related peptide (CGRP) Isolated vascularly
perfused stomach Vagus stimulation
Introduction
Chili peppers are known to have pharmacological effects, such as the ability to improve appetite and digestion. Recent ndings have revealed the gastro-protective effects of capsaicin and red pepper. Kang et al. [1] reported that among Chinese patients, chili protected against peptic ulcers. However, capsaicin, a chili pepper constituent that also occurs endogenously in humans, has been reported to cause acute erosive gastritis when administered orally...