Activation of lumbar spinal wide-dynamic range neurons by a sanshool derivative

J Neurophysiol. 2009 Apr;101(4):1742-8. doi: 10.1152/jn.91311.2008. Epub 2009 Jan 21.

Abstract

The enigmatic sensation of tingle involves the activation of primary sensory neurons by hydroxy-alpha-sanshool, a tingly agent in Szechuan peppers, by inhibiting two-pore potassium channels. Central mechanisms mediating tingle sensation are unknown. We investigated whether a stable derivative of sanshool-isobutylalkenyl amide (IBA)-excites wide-dynamic range (WDR) spinal neurons that participate in transmission of chemesthetic information from the skin. In anesthetized rats, the majority of WDR and low-threshold units responded to intradermal injection of IBA in a dose-related manner over a >5-min time course and exhibited tachyphylaxis at higher concentrations (1 and 10%). Almost all WDR and low-threshold units additionally responded to the pungent agents mustard oil (allyl isothiocyanate) and/or capsaicin, prompting reclassification of the low-threshold cells as WDR. The results are discussed in terms of the functional role of WDR neurons in mediating tingle sensation.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Action Potentials / drug effects
  • Amides / pharmacology*
  • Animals
  • Capsaicin / pharmacology
  • Cold Temperature
  • Dose-Response Relationship, Drug
  • Hot Temperature
  • Isothiocyanates / pharmacology
  • Lumbosacral Region
  • Male
  • Nonlinear Dynamics*
  • Physical Stimulation / methods
  • Rats
  • Rats, Sprague-Dawley
  • Sensory Receptor Cells / classification
  • Sensory Receptor Cells / drug effects*
  • Sensory System Agents / pharmacology
  • Sensory Thresholds / drug effects
  • Sensory Thresholds / physiology
  • Skin / innervation
  • Spinal Cord / cytology*

Substances

  • Amides
  • Isothiocyanates
  • Sensory System Agents
  • sanshool
  • 2,3,4-tri-O-acetylarabinopyranosyl isothiocyanate
  • Capsaicin