Kappa- and delta-opioids block sympathetically dependent hyperalgesia

J Neurosci. 1991 Apr;11(4):928-32. doi: 10.1523/JNEUROSCI.11-04-00928.1991.

Abstract

Direct hyperalgesia induced by prostaglandin E2 (PGE2) can be blocked by mu- but not delta- or kappa-opioids. However, there is evidence that kappa- and delta-opioid receptors are located on sympathetic postganglionic neuron (SPGN) terminals, which mediate bradykinin (BK) hyperalgesia via SPGN-terminal-dependent production of PGE2. Therefore, we evaluated the antinociceptive effect of delta- and kappa-opioids on BK hyperalgesia. We demonstrate that the mechanical hyperalgesia induced by intradermal injection of BK can be blocked by the kappa-opioid agonist trans-3,4-dichloro-N-methyl-N[2-(-pyrrolidinyl)cyclo-hexyl] benzeneacetamide (U50,488H) and by the delta-opioid agonist (D-Pen2,5)-enkephalin (DPDPE), as well as the mu-opioid agonist Tyr-D-Ala-Gly-NMe-Phe-Gly-ol(DAMGO). Pertussis toxin prevented the inhibition of BK-induced hyperalgesia by U50,488H, DPDPE, or DAMGO. We conclude that the observed peripheral analgesic effects of kappa- and delta-opioid agonists result from actions upon SPGN terminals and that these effects are mediated by inhibitory G-proteins.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • Bradykinin / pharmacology
  • Dose-Response Relationship, Drug
  • Endorphins / pharmacology*
  • Endorphins / physiology
  • Hyperalgesia / chemically induced
  • Hyperalgesia / physiopathology*
  • Male
  • Naloxone / pharmacology
  • Nociceptors / drug effects
  • Pertussis Toxin
  • Rats
  • Rats, Inbred Strains
  • Sensory Thresholds / drug effects
  • Sympathetic Nervous System / physiopathology*
  • Virulence Factors, Bordetella / pharmacology

Substances

  • Endorphins
  • Virulence Factors, Bordetella
  • Naloxone
  • Pertussis Toxin
  • Bradykinin