Capsazepine inhibits thermal hyperalgesia but not nociception triggered by protease-activated receptor-2 in rats

Jpn J Pharmacol. 2002 Jun;89(2):184-7. doi: 10.1254/jjp.89.184.

Abstract

Protease-activated receptor-2 (PAR-2), expressed in sensory neurons, triggers thermal hyperalgesia, nociceptive behavior and spinal Fos expression in rats. In the present study, we examined if the nociceptive processing by PAR-2 is mediated by trans-activation of capsaicin receptors. The thermal hyperalgesia following an intraplantar (i.pl.) administration of the PAR-2-activating peptide SLIGRL-NH2 was completely abolished by the capsaicin receptor antagonist capsazepine. In contrast, neither the nociceptive behavior nor spinal Fos expression in response to i.pl. SLIGRL-NH2 were attenuated by capsazepine. Our data imply that trans-activation of capsaicin receptors by PAR-2 might be involved in the PAR-2-triggered thermal hyperalgesia, but not nociception.

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Capsaicin / analogs & derivatives*
  • Capsaicin / pharmacology*
  • Capsaicin / therapeutic use
  • Hot Temperature*
  • Hyperalgesia / chemically induced*
  • Male
  • Pain / chemically induced
  • Pain / drug therapy*
  • Peptide Fragments / chemistry
  • Peptide Fragments / toxicity*
  • Rats
  • Rats, Wistar
  • Receptor, PAR-2
  • Receptors, Thrombin / chemistry*

Substances

  • Peptide Fragments
  • Receptor, PAR-2
  • Receptors, Thrombin
  • capsazepine
  • Capsaicin