A capsaicin-receptor antagonist, capsazepine, reduces inflammation- induced hyperalgesic responses in the rat: Evidence for an endogenous capsaicin-like substance

J. Y. Kwak, J. Y. Jung, S. W. Hwang, W. T. Lee, U. Oh

Research output: Contribution to journalArticlepeer-review

96 Citations (Scopus)

Abstract

In the present study, the presence of an endogenous capsaicin-like substance and the role of capsaicin receptors in nociception during inflammation were assessed using Fos immunohistochemistry and the paw- withdrawal test in rats. Intradermal injection of carrageenan in the hind- paw produced inflammation in the foot pad, increased the number of cells exhibiting Fos-like immunoreactivity in the dorsal horn of the spinal cord, and decreased the paw-withdrawal latency. Intradermal injection of capsazepine, a capsaicin-receptor antagonist, significantly reduced the number of cells exhibiting Fos-like immunoreactivity, significantly increased the paw-withdrawal latency, but did not decrease inflammation induced by carrageenan injection. Intradermal injection of capsaicin or formalin also increased Fos-positive neurons. Capsaicin- or formalin-induced Fos expression was reduced in both cases by pretreatment of capsazepine, but to a much lesser extent for formalin. The capsazepine inhibition of carrageenan inflammation-induced hyperalgesic responses strongly suggests that an endogenous capsaicin-like substance is released in inflamed tissues and produces nociceptive neural impulses by acting on capsaicin receptors present on sensory neurons. Furthermore, our results indicate that capsaicin receptors take part only in generating nociceptive signals in sensory neurons, but not in activating the inflammation-promoting cells.

Original languageEnglish
Pages (from-to)619-626
Number of pages8
JournalNeuroscience
Volume86
Issue number2
DOIs
Publication statusPublished - 1998 Jun 1
Externally publishedYes

Keywords

  • Capsaicin receptor
  • Capsazepine
  • Fos immunohistochemistry
  • Inflammation
  • Pain

ASJC Scopus subject areas

  • Neuroscience(all)

Fingerprint Dive into the research topics of 'A capsaicin-receptor antagonist, capsazepine, reduces inflammation- induced hyperalgesic responses in the rat: Evidence for an endogenous capsaicin-like substance'. Together they form a unique fingerprint.

Cite this