Methyl salicylate as a cutaneous stimulus: a psychophysical analysis.

Two experiments were performed to examine the perceptual effects of methyl salicylate on hairy skin in humans. In the first experiment, the sensitivity to methyl salicylate (prepared in an ethanol and water vehicle and applied via filter paper) was measured in a paradigm that required subjects to report both the perceived intensity and the perceptual quality of the sensations they experienced. The results indicated that methyl salicylate could be reliably detected at concentrations between 3 and 12%. Peak perceived intensities increased with increasing concentration, and the dominant sensation quality reported was "burning". The second experiment, which measured the effect of methyl salicylate on the perception of temperature change, revealed that the compound enhances the perception of warming but does not affect the perception of cooling. For most subjects, methyl salicylate produced a hyperalgesia to heating. Overall, the data suggest that methyl salicylate probably produces its sensory effects via stimulation and/or sensitization of a population of cutaneous nociceptors.