Capsazepine as a selective antagonist of capsaicin-induced activation of C-fibres in guinea-pig bronchi

Eur J Pharmacol. 1992 May 14;215(2-3):341-4. doi: 10.1016/0014-2999(92)90054-8.


We investigated the action of capsazepine, an antagonist of the actions of capsaicin on sensory neurones, on the contractile responses evoked by capsaicin or by electrical field stimulation (EFS) in guinea-pig bronchi. Capsazepine (10(-5) M) selectively inhibited responses to capsaicin, producing a significant change in EC50 values but not the Hill coefficient (nH), suggesting that capsazepine acts as a competitive antagonist (apparent pKB = 5.12) whereas ruthenium red is a non-competitive antagonist. Capsazepine and ruthenium red were without effect on EFS-induced responses.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Bronchi / drug effects
  • Bronchi / innervation*
  • Capsaicin / analogs & derivatives*
  • Capsaicin / antagonists & inhibitors*
  • Capsaicin / pharmacology
  • Electric Stimulation
  • Guinea Pigs
  • In Vitro Techniques
  • Isometric Contraction / drug effects
  • Male
  • Nerve Fibers / drug effects*
  • Ruthenium Red / pharmacology
  • Tetrodotoxin / pharmacology


  • Ruthenium Red
  • Tetrodotoxin
  • capsazepine
  • Capsaicin