Capsaicin sensitization and desensitization on the tongue produced by brief exposures to a low concentration

Neurosci Lett. 1989 Dec 15;107(1-3):173-8. doi: 10.1016/0304-3940(89)90812-4.

Abstract

The intensity of sensations of burning and stinging produced by repeated exposures to capsaicin (at a nominal concentration of 3 ppm) was measured on a localized area of the tongue as a function of both the number of exposures and the time between them. It was discovered in the initial experiment that stimulation at the rate of 1/min (for up to 25 min) resulted in a monotonic increase in the intensity of burning sensations in a manner consistent with the phenomenon of sensitization. However, the insertion of a 15-min delay in stimulation resulted in a reduction in the intensity of the sensations produced by further stimulation, i.e., desensitization occurred. Desensitization was statistically significant even after exposure to as few as 5 stimuli prior to the delay. A subsequent experiment established that the minimum delay necessary to produce desensitization was between 2.5 and 5 min. Hence, paradoxically, the sensory response to capsaicin on the tongue increased as stimulation continued, then decreased after stimulation had ceased.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Adult
  • Capsaicin / pharmacology*
  • Drug Tolerance
  • Female
  • Humans
  • Male
  • Nociceptors / drug effects*
  • Reaction Time
  • Tongue / drug effects
  • Tongue / innervation*

Substances

  • Capsaicin