Acute intragastric application of capsaicin inhibits 2-deoxy-D-glucose--but not histamine-induced gastric acid secretion in the dog.

In this study the influence of acute exposure of gastric mucosa to the sensory neurotoxin capsaicin on basal gastric acid secretion and on secretion induced by 2-deoxy-D-glucose or histamine in conscious dogs with gastric fistulae has been investigated. Under basal conditions intragastric capsaicin (160 microM, 50 ml of volume) did not induce any significant change in acid secretion and in plasma levels of gastrin. Total acid output induced by 2-deoxy-D-glucose (75 mg/kg i.v.) was significantly decreased by intragastric application of capsaicin, while plasma gastrin concentrations were unaffected. A direct stimulant of the parietal cells, such as histamine (64 micrograms/kg s.c.) increased gastric acid secretion which was not sensitive to capsaicin pretreatment. These findings indicate the involvement of capsaicin-sensitive fibers in the control of vagally-induced gastric acid secretion in the dog.