Accession Number : ADA200553

Title :   Characterization of an Opioid-Like Hibernation Induction Trigger.

Descriptive Note : Annual rept. 31 Mar 87-30 Mar 88,

Corporate Author : KENTUCKY UNIV RESEARCH FOUNDATION LEXINGTON

Personal Author(s) : Oeltgen, Peter R.

Report Date : 01 APR 1988

Pagination or Media Count : 37

Abstract : To examine the possible involvement of multiple opioid receptors and the pineal gland in animal hibernation, we infused opioids selective for mu, kappa, and delta opioid receptors and the pineal specific hormone, melatonin, into summer-active ground squirrels (Citellus tridecemlineatus). The effects of those opioid treatments and melatonin on the hibernation induced by HIT (Hibernation Induction Trigger) were also examined. Mu opioids morphine (1.50 mg/kg/day) and morphiceptin (0.82 mg/kg/day) and Kappa opioid peptide dynorphin A (0.82 mg/kg/day) and U-69593 (0.48 mg/kg/day) did not induce hibernation. On the contrary, morphine, morphiceptin, dynorphin A and U-69593 antagonized HIT-induced hibernation in summer-active ground squirrels. Infusion of delta opioid DADLE (D-Ala2-Leu5-Enkephalin; 1.50 mg/kg/day) and melatonin; (1.50 mg/kg/day), however, induced summer hibernation in a manner comparable to that induced by HIT. It is concluded therefore that melatonin and the delta opioid receptor and its ligand may be intimately involved in animal hibernation. In view of the fact that HIT was obtained from winter hibernating animals and might therefore be responsible for natural hibernation, our results also suggest that naturally occurring mu and kappa opioids may play an important role in the arousal state of hibernation. (AW)

Descriptors :   *HIBERNATION, *HORMONES, *PINEAL GLAND, *OPIUM ALKALOIDS, ANIMALS, INFUSIONS, MORPHINE, SUMMER.

Subject Categories : Pharmacology
      Anatomy and Physiology
      Biochemistry

Distribution Statement : APPROVED FOR PUBLIC RELEASE