D-amphetamine-induced hypothermia and hypermotility in rats: Changes after systemic administration of beta-endorphin

Shlomo Yehuda, James Zadina, Abba J. Kastin, David H. Coy

Research output: Contribution to journalArticlepeer-review

25 Scopus citations


Systemically administered beta-endorphin was tested in rats for its ability to modify the hypothermia and hypermotility induced by d-amphetamine. Colonic temperature and motor activity were measured in a cold (4°C) ambient temperature in animals given IP injections of beta-endorphin (0.1, 1.0, or 3.0 mg/kg), naloxone (10 mg/kg), or morphine (30 mg/kg). The same measurements were taken in animals given beta-endorphin (1.0 mg/kg) in combination with naloxone or saline pretreatment and d-amphetamine (15 mg/kg) or saline post-treatment. Morphine alone had a biphasic effect on thermoregulation, but did not affect d-amphetamine-induced hypothermia. Activity scores were decreased by morphine, in both d-amphetamine and saline treated animals. The thermal response of rats to beta-endorphin alone was variable, depending on dosage, but all 3 dosages partially blocked the hypothermic effect of d-amphetamine. Naloxone blocked the thermal effects of both beta-endorphin and d-amphetamine. Motor activity tended to be decreased by naloxone, regardless of amphetamine treatment, but beta-endorphin tended to increase activity in amphetamine-treated animals and reduce it in saline-treated controls. In their actions on both thermoregulation and activity, naloxone and beta-endorphin appeared to interact independently with d-amphetamine, often producing effects in the same direction, but in combination, they tended to be mutually inhibitory.

Original languageEnglish
Pages (from-to)179-185
Number of pages7
Issue number2
StatePublished - 1980
Externally publishedYes

Bibliographical note

Funding Information:
Supported in part by the Medical Research Service of the Veterans Administration, NIH (NS 07664), NIDA (DA 01806), and The American Parkinson Disease Foundation.


  • Beta-endorphin
  • Drug interaction
  • Hypothermia
  • Morphine
  • Motor activity
  • Naloxone
  • Peptide
  • d-Amphetamine


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