Arousal following intra-preoptic area administration of naltrexone, ICI 174864 or nor-BNI in hibernating ground squirrels.
Experiments were performed from January 1 to 30 January, 1989. Drugs were administered to the preoptic area of hibernating ground squirrels through a chronically implanted cannula on the 2nd day of a torpor bout. When naltrexone (an antagonist of opioid receptor) was injected, part (naltrexone, 0.5 or 1 microgram/microliter/32 min) or all (naltrexone, 2 micrograms/microliters/32 min) of the animals' body temperature was increased and they aroused from hibernation within 20 h after the injection. Further experiments showed that intra-preoptic area perfusion of 1 nmol of ICI 174864 (an antagonist of delta receptor) or nor-BNI (an antagonist of kappa receptor), but not beta-FNA (an antagonist of mu receptor), were able to increase the body temperature of hibernating ground squirrels and arouse them from hibernation in 20 h after the injection. These results indicate that (1) opioid peptides in the preoptic area may be involved in the mechanisms of hibernation; (2) activation of delta and kappa receptors in the preoptic area is indispensable for the maintenance of hibernation in ground squirrels.
Yu
L C
LC
Department of Physiology, Peking University, Beijing, People's Republic of China.
Cai
Y P
YP
D000818:Animals; D001143:Arousal / Q000187:drug effects*; D001931:Brain Mapping; D004305:Dose-Response Relationship, Drug; D004743:Enkephalin, Leucine / Q000031:analogs & derivatives* / Q000494:pharmacology; D005260:Female; D006605:Hibernation / Q000187:drug effects*; D008297:Male; D009271:Naltrexone / Q000031:analogs & derivatives* / Q000494:pharmacology*; D009292:Narcotic Antagonists / Q000494:pharmacology*; D011301:Preoptic Area / Q000187:drug effects*; D017465:Receptors, Opioid, delta / Q000187:drug effects; D017473:Receptors, Opioid, kappa / Q000187:drug effects; D012589:Sciuridae
D009292:Narcotic Antagonists; D017465:Receptors, Opioid, delta; D017473:Receptors, Opioid, kappa; C051844:norbinaltorphimine; D004743:Enkephalin, Leucine; D009271:Naltrexone; C040643:N,N-diallyl-tyrosyl-alpha-aminoisobutyric acid-phenylalanyl-leucine