Different types of opioid receptors mediating analgesia induced by morphine, DAMGO, DPDPE, DADLE and beta-endorphin in mice

Naunyn Schmiedebergs Arch Pharmacol. 1990 Jul;342(1):67-71. doi: 10.1007/BF00178974.

Abstract

The effects of intracerebroventricular (i.c.v.) administration of D-Phe-Cys-Tyr-D-Try-Orn-Thr-Pen-Thr-NH2 (CTOP), a selective mu-opioid receptor antagonist, (Allyl)2-Tyr-Aib-Aib-Phe-Leu-OH (ICI 174864) and (N,N-Bisallyl-Tyr-Gly-Gly-psi-(CH2S)-Phe-Leu-OH (ICI 154129), selective delta-opioid receptor antagonists on blocking analgesia induced by beta-endorphin, morphine, D-Ala2-NMePhe4-Gly-ol-enkephalin (DAMGO), D-Ala2-D-Leu5-enkephalin (DADLE) and D-Pen2-enkephalin (DPDPE) administered i.c.v. were studied in male ICR mice. The analgesia was assessed by the tail-flick and paw-licking (hot-plate) tests. The potencies of opioid agonists injected i.c.v. for producing analgesia were DAMGO greater than DADLE greater than beta-endorphin greater than morphine greater than DPDPE. Intracerebroventricular administration of CTOP (0.05 micrograms) selectively antagonized inhibition of the tail-flick and paw-licking response induced by morphine, DAMGO or DADLE but not beta-endorphin or DPDPE. ICI 174864 (5 micrograms) and ICI 154129 (5 micrograms) injected i.c.v. selectively antagonized analgesia induced by DPDPE or DADLE but not beta-endorphin, morphine or DAMGO injected i.c.v. These results indicate that analgesia induced by morphine and DAMGO is mediated by the stimulation of mu-opioid receptors while analgesia induced by DPDPE is mediated by the stimulation of delta-opioid receptors. DADLE-induced analgesia is mediated by the stimulation of both mu- and delta-opioid receptors. Analgesia induced by beta-endorphin is mediated by neither mu- nor delta-opioid receptors.

Publication types

  • Comparative Study
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Analgesia*
  • Animals
  • Endorphins / pharmacology*
  • Enkephalin, Ala(2)-MePhe(4)-Gly(5)-
  • Enkephalin, D-Penicillamine (2,5)-
  • Enkephalin, Leucine / analogs & derivatives
  • Enkephalin, Leucine / pharmacology
  • Enkephalin, Leucine-2-Alanine
  • Enkephalins / pharmacology
  • Injections, Intraventricular
  • Male
  • Mice
  • Mice, Inbred ICR
  • Morphine / pharmacology*
  • Narcotic Antagonists / pharmacology
  • Reaction Time / drug effects
  • Receptors, Opioid / drug effects*
  • Receptors, Opioid / physiology
  • Somatostatin / analogs & derivatives
  • Somatostatin / pharmacology
  • beta-Endorphin / pharmacology

Substances

  • Endorphins
  • Enkephalins
  • Narcotic Antagonists
  • Receptors, Opioid
  • Enkephalin, Ala(2)-MePhe(4)-Gly(5)-
  • phenylalanyl-cyclo(cysteinyltyrosyl-tryptophyl-ornithyl-threonyl-penicillamine)threoninamide
  • Somatostatin
  • Enkephalin, Leucine
  • beta-Endorphin
  • Enkephalin, Leucine-2-Alanine
  • Morphine
  • Enkephalin, D-Penicillamine (2,5)-
  • N,N-diallyl-tyrosyl-alpha-aminoisobutyric acid-phenylalanyl-leucine
  • ICI 154129