Possible Interaction: Capsaicin and Menthol

“Previous research had shown that treating the tongue with menthol 15 min before exposure to capsaicin could enhance the irritancy of capsaicin, and we wished to learn if this effect would increase as the time between exposure to menthol and capsaicin decreased.”

“We examined the duration of this apparent crossdesensitization in a second experiment by varying the delay between exposure to menthol and a block of three consecutive capsaicin stimuli.”

“We found instead that when capsaicin followed menthol by only 3.5 min, or when it was presented in mixture with menthol for 2-3 min, sensory irritation was reduced rather than enhanced.”

“The results 1) confirmed self-desensitization for both chemicals, 2) demonstrated cross-desensitization of menthol by capsaicin , and 3) revealed cross-sensitization of capsaicin by menthol.”

“An in vivo sensory irritation test showed that menthol conferred an analgesic effect on the sensory irritation evoked by a capsaicin analogue.”

“hTRPV1 currents activated by heat and capsaicin were inhibited by menthol , whereas hTRPM8 currents activated by cold and menthol were similarly inhibited by capsaicin.”

“ L‐menthol effectively diminished pain behavior elicited by chemical stimuli ( capsaicin , acrolein, acetic acid), noxious heat, and inflammation (complete Freund’s adjuvant).”

“4 We have shown that menthol attenuates both capsaicin and NKA‐induced bronchoconstriction in vivo and relaxes KCl and ACh preconstricted bronchi in vitro.”

“In diabetic mice, intraplantar injection of capsaicin , a TRPV1 agonist-induced nocifensive behavior but the severity of this behavior was significantly lower when co-administered with menthol , a TRPM8 agonist.”