Characterization of an Opioid-Like Hibernation Induction Trigger

摘要

A hibernation induction trigger (HIT) molecule derived from the plasma of deeplyhibernating woodchucks exerts profound effects mimicking a hibernation-like state when infused I.C.V. or I.V. in primates. The profound opiate-like behavioral and physiological depression occurring shortly after the infusion of the HIT-containing albumin fraction includes hypothermia, bradycardia, long-term hypophagia and markedly depressed renal function. All of the aforementioned effects are reversed or retarded by the infusion of the opiate antagonists, naloxone and naltrexone. Such evidence enforces our hypothesis that the HIT molecule is not specific for hibernators, but that it may initiate its action through specific opioid receptor(s). We have shown that only DADLE, a delta class of opioid, could induce hibernation in summer-active ground squirrels (the traditional bioassay) in a fashion similar to those injected with HIT. Such evidence indicates that this delta opioid mimics the action of the HIT molecule and may be intimately involved in natural and summer-induced hibernation.