Effect of mu-, kappa-, and delta-selective opioid agonists on thermoregulation in the rat

Pharmacol Biochem Behav. 1992 Dec;43(4):1209-16. doi: 10.1016/0091-3057(92)90504-9.


The effect of selective mu-, kappa-, and delta-agonists on brain surface temperature (Tb), oxygen consumption (Vo2), and heat exchange (Q) was studied in unrestrained, male Sprague-Dawley rats using whole-body calorimetry. Hyperthermia, produced by PL-017 (1.86 nM) given ICV, resulted from increased Vo2 and reduced Q during the first 15-45 min postinjection. Tb returned to control levels due to a combination of increased Q and reduced Vo2. PL-017-induced hyperthermia was abolished by the mu-selective antagonist CTAP (0.75 nM). Dynorphin A1-17 (4.65 nM), a kappa-selective agonist, reduced both Vo2 and Q, resulting in hypothermia that was blocked by the kappa-selective antagonist nor-binaltorphimine (25 nM). The delta-selective agonist DPDPE (4.64 nM) caused no significant changes in Tb, Vo2, or Q. The data indicate that central stimulation of the mu- and kappa-opioid receptors affects both oxidative metabolism and heat exchange, which result in a change in Tb. These alterations can be prevented with selective opioid antagonist pretreatment.

Publication types

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

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Body Temperature / drug effects
  • Body Temperature Regulation / drug effects*
  • Brain / drug effects
  • Brain / physiology
  • Dose-Response Relationship, Drug
  • Dynorphins / pharmacology
  • Endorphins / pharmacology
  • Enkephalin, D-Penicillamine (2,5)-
  • Enkephalins / pharmacology
  • Indoles / pharmacology
  • Injections, Intraventricular
  • Male
  • Molecular Sequence Data
  • Morphinans / pharmacology
  • Naltrexone* / analogs & derivatives*
  • Narcotic Antagonists / pharmacology
  • Oxygen Consumption / drug effects
  • Rats
  • Rats, Sprague-Dawley
  • Receptors, Opioid, delta / drug effects*
  • Receptors, Opioid, kappa / drug effects*
  • Receptors, Opioid, mu / drug effects*


  • Endorphins
  • Enkephalins
  • Indoles
  • Morphinans
  • Narcotic Antagonists
  • Receptors, Opioid, delta
  • Receptors, Opioid, kappa
  • Receptors, Opioid, mu
  • Naltrexone
  • Dynorphins
  • morphiceptin, N-Me-Phe(3)-
  • Enkephalin, D-Penicillamine (2,5)-
  • naltrindole