Dynorphin, a preferential ligand for kappa-opioid receptors, is present in nerve fibers and immune cells within inflamed tissue of the rat

Neurosci Lett. 1992 Jun 8;140(1):85-8. doi: 10.1016/0304-3940(92)90688-4.


Exogenous kappa-opioid agonists have been shown to produce peripheral antinociceptive effects in inflamed tissue. This study sought to determine whether endogenous kappa-receptor ligands are present at the site of inflammation. In Freund's adjuvant-induced hindpaw inflammation in the rat, we show, by immunohistochemistry, that dynorphin is detectable within inflammatory cells and in the cutaneous nerves in a similar distribution as calcitonin gene-related peptide, a specific marker for sensory neurons. These findings extend our previous observations in that not only beta-endorphin and Met-enkephalin (mu- and delta-receptor ligands), but also a preferential kappa-ligand is present within inflamed subcutaneous tissue.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Calcitonin Gene-Related Peptide / analysis
  • Dynorphins / analysis
  • Dynorphins / metabolism*
  • Freund's Adjuvant
  • Inflammation / physiopathology*
  • Male
  • Nerve Fibers / physiology*
  • Nerve Fibers / ultrastructure
  • Pain / physiopathology*
  • Rats
  • Rats, Wistar
  • Receptors, Opioid, kappa / physiology*
  • Skin / innervation*
  • Skin / pathology


  • Receptors, Opioid, kappa
  • Dynorphins
  • Freund's Adjuvant
  • Calcitonin Gene-Related Peptide