A stock solution of capsaicin (Sigma Aldrich, Sweden AB,
Stockholm, M2028) [1 mmol/L in ethanol (99.5%)] was
prepared and then dissolved in 0.9% saline to provide a
stock solution of 500 mmol/L capsaicin. Fresh serial dilutions
were prepared from this stock solution, using saline
diluent to produce doubling concentrations from 0.49 to
500 mmol/L.
Capsaicin provocation with the single-breath