Effects of cold acclimation and central opioid processes on thermoregulation in rats

doi:10.1016/0091-3057(95)02124-8

Pharmacology Biochemistry and Behavior

Volume 54, Issue 2, May 1996, Pages 317-325

https://doi.org/10.1016/0091-3057(95)02124-8 Get rights and content

Abstract

Two experiments, using centrally administered [d-Ala²-MePhe⁴-Gly(ol)⁵]enkephalin (DAMGO), a selective μ-opioid agonist, assessed the thermoregulatory consequences of cold acclimation. Experiment 1 assessed whether cold acclimation influenced DAMGO hyperthermia at room temperature. Sialoadenectomized rats were implanted with ICV cannulae and IP Mini-Mitters. After 3 weeks of exposure to 5 °C (cold acclimation) or 22 °C (non-cold acclimation) rats were pretreated with IP naltrexone HC1 (2 mg/kg b.wt.) or vehicle (0.15 M saline) and later administered a 5-μI ICV injection of 0.15 M saline, 0.1, or 1.0 μg DAMGO. Cold acclimation exerted little effect on core temperature but potentiated DAMGO hyperthermia in a dose-dependent, naltrexone-reversible, activity-independent manner. Experiment 2 assessed the effect these same manipulations exerted on operant escape from a convective source of mild heat (37 °C). Duration of heat escape increased with cold acclimation in a naltrexone-resistant manner, yet was not influenced by DAMGO in either non-cold-acclimated or cold-acclimated rats. These findings suggest that two central adaptations occur with cold acclimation: A non-μ-opioid process that increases heat sensitivity and a μ-opioid process that potentiates hyperthermia but fails to alter heat escape due to μ-opioid-mediated analgesia.

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ArticleEffects of cold acclimation and central opioid processes on thermoregulation in rats

Abstract

Peptides

Int. Rev. Neurobiol.

J. Thermal. Biol.

Physiol. Behav.

Neuropharmacology

Biochem. Biophys. Res. Commun.

Brain Res.

Regul. Pept.

Physiol. Behav.

The opioid system and temperature regulation

Annu. Rev. Pharmacol. Toxicol.

Exercise suppression of thermoregulatory thermogenesis in warm- and cold-acclimated rats

Can. J. Physiol. Pharmacol.

Behavioural and pharmacological studies of morphine-induced excitation of rats. Possible relation to brain catecholamines

Psychopharmacologia

Naloxone, naltrexone and related noroxymorphones

Opioids and opioid receptors in thermoregulation

Cold exposure and heat reinforced opérant behavior

Science

Temperature acclimation in birds and mammals

Annu. Rev. Physiol.

A description of the salivary glands of the rat and a procedure for their extirpation

J. Dent. Res.

Effects of heat and cold on the albino rat: Crossed resistance or crossed extinction?

J. Appl. Physiol.

Participation of alpha-adrenoreceptors in brown adipose tissue thermogenesis in vivo

Int. J. Obes.

Minimal exposure needed to acclimatize rats to cold

Am. J. Physiol.

Effects of extremes of temperatures on hypertensive rats

Am. J. Physiol.

Induction of excessive grooming in the rat by fragments of lipotropin

Nature

Naltrexone: A review of its pharmodynamic and pharmokinetic properties and therapeutic efficacy in the management of opioid dependence

Drugs

Saliva spreading activity and body temperature regulation in the rat

Am. J. Physiol.

Rodents

Thermogenesis due to exercise and cold in warm- and cold-acclimated rats

Can. J. Biochem. Physiol.

Brown adipose tissue thermogenesis: Role in thermoregulation, energy regulation and obesity

Article
Effects of cold acclimation and central opioid processes on thermoregulation in rats