Temporal gustatory and salivary responses to capsaicin upon repeated stimulation.

Repeated oral stimulation with solutions of 2 ppm capsaicin increased time to maximum intensity, but yielded a decrease in sequential mouth-burn intensity due to a rising minimum irritation rating between stimuli. Two response patterns were observed: for 18 subjects mouth-burn increased, while 14 subjects showed depression upon repeated stimulation. Because of across-subject variability, there was little correlation between parotid salivary response and perceived sensory responses. Capsaicin-stimulated salivary flow was significantly higher than flow stimulated by distilled water in 9 high-flow subjects, but not in 14 low-flow subjects. Oral adaptation to capsaicin may attenuate parotid salivary response, although eaters and noneaters of chili peppers did not differ significantly in their perception of mouth-burn or in salivary flow.