Abstract
Capsaicin and 6-gingerol, pungent components of chilli pepper and ginger, are known
as dietary agonists of transient receptor potential vanilloid-1. Transient receptor
potential vanilloid-1 nerve fibers are recognized to play a role in gastric mucosal
integrity in rats. In the present studies, we examined the acute effects of peroral
administration of capsaicin and 6-gingerol on gastric acid secretion in conscious
mice. These agents were given p. o. 30 min before the pylorus was ligated. Oral administration
of capsaicin (1.0–100 mg/kg) or 6-gingerol (1.5–50 mg/kg) significantly and dose-dependently
inhibited basal acid secretion. Pretreatment with BCTC, a transient receptor potential
vanilloid-1 antagonist, significantly reversed the reduced basal acid secretion by
capsaicin or 6-gingerol. The combination of the lowest doses of capsaicin and 6-gingerol
markedly inhibited basal acid secretion in conscious mice and this was also significantly
reversed by BCTC. Moreover, the combination of the maximal dose of capsaicin and 6-gingerol
inhibited basal acid secretion only to the level of a single administration of the
maximal dose of capsaicin. These results suggest that the combination of capsaicin
and 6-gingerol has an additive effect on the inhibition of gastric acid secretion
through activation of transient receptor potential vanilloid-1. In separate experiments,
intraduodenal administration of either capsaicin (30 mg/kg) or 6-gingerol (15 mg/kg),
whose doses were observed to have a significant inhibitory effect by oral administration,
tended to inhibit basal acid secretion compared with the vehicle. These results suggest
that the combination of capsaicin and 6-gingerol has an additive effect on inhibition
of gastric acid secretion through activation of transient receptor potential vanilloid-1,
and oral administration of transient receptor potential vanilloid-1 agonists directly
stimulates transient receptor potential vanilloid-1 in the gastric lumen, resulting
in a potent reduction of gastric acid secretion.
Key words
capsaicin - 6-gingerol - transient receptor potential vanilloid-1 - TRPV1 - gastric
acid secretion - mice