title: The influence of opiate agonists on day-night feeding rhythms in young and old mice.
abstract: Daily rhythms of feeding behavior and responses to ketocyclazocine, morphine and naloxone were measured in young (1-2 months) and old (24-30 months) male CF-1 mice. All of the mice consumed more food at night than in the day-time, though this nocturnal peak was markedly reduced in the old animals, who consumed more in the day. The young mice also displayed a significant nocturnal enhancement in ketocyclazocine- and morphine-stimulated feeding. This day-night rhythm in ingestive responses was absent in the old mice. In comparison to the young mice, the opiate-stimulated food consumptions of the old animals were reduced at all times. Additionally, the old animals failed to show any day-night variations in the suppressive effects of naloxone on deprivation-induced food intake that were displayed by the young animals.
authors.forename: M
authors.initials: M
authors.lastname: Kavaliers
authors.forename: M
authors.initials: M
authors.lastname: Hirst
mesh_terms: D000375:Aging; D000818:Animals; D003496:Cyclazocine / Q000031:analogs & derivatives / Q000494:pharmacology; D004723:Endorphins / Q000502:physiology*; D016314:Ethylketocyclazocine / Q000031:analogs & derivatives*; D005247:Feeding Behavior / Q000187:drug effects / Q000502:physiology*; D008297:Male; D051379:Mice; D009020:Morphine / Q000494:pharmacology; D009270:Naloxone / Q000494:pharmacology; D010507:Periodicity; D011957:Receptors, Opioid / Q000502:physiology*; D017473:Receptors, Opioid, kappa; D017450:Receptors, Opioid, mu
chemical_list: D004723:Endorphins; D011957:Receptors, Opioid; D017473:Receptors, Opioid, kappa; D017450:Receptors, Opioid, mu; D009270:Naloxone; D016314:Ethylketocyclazocine; C012395:ketazocine; D009020:Morphine; D003496:Cyclazocine