Characterization of an Opioid-Like Hibernation Induction Trigger.
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)
Document Details
- Document Type
- Technical Report
- Publication Date
- Apr 01, 1988
- Accession Number
- ADA200553
Entities
People
- Peter R. Oeltgen
Organizations
- University of Kentucky