title: Effect of naloxone on intake of cornstarch, sucrose, and polycose diets in restricted and nonrestricted rats.
abstract: We studied the effect of the opioid receptor antagonist naloxone on intake of three isocaloric diets containing cornstarch, sucrose, or Polycose as the predominant carbohydrate in ad libitum-fed and food-restricted rats. A large body of evidence suggests that opioids affect palatability (reward)-rater than hunger (energy deficit)-driven food intake. We expected food intake to be driven by both energy needs and palatability in ad libitum-fed rats, whereas in food-restricted rats we expected intake to be driven by energy needs with a relatively small palatability component in the preferred sucrose and Polycose diet groups. In the ad libitum-fed rats, naloxone significantly reduced nocturnal intake of all three diets at doses of 0.3, 1.0, and 3.0 mg/kg. In contrast, naloxone failed to alter intake of the cornstarch diet in chronically food-restricted rats. However, naloxone decreased intake of the sucrose diet in food-restricted rats at doses of 0.3, 1.0, and 3.0 mg/kg and decreased intake of the Polycose diet at the 3 mg/kg dose. These data lend further support to the notion that opioids are involved in some other component of feeding than that induced by energy needs.
authors.affiliation: Department of Medicine and Geriatric Research, Veterans Affairs Medical Center, Minneapolis, Minnesota 55417, USA.
authors.forename: D T
authors.initials: DT
authors.lastname: Weldon
authors.forename: E
authors.initials: E
authors.lastname: O'Hare
authors.forename: J
authors.initials: J
authors.lastname: Cleary
authors.forename: C J
authors.initials: CJ
authors.lastname: Billington
authors.forename: A S
authors.initials: AS
authors.lastname: Levine
mesh_terms: D000818:Animals; D000855:Anorexia / Q000139:chemically induced; D004032:Diet; D004435:Eating / Q000187:drug effects*; D005508:Food Deprivation; D005518:Food Preferences; D005936:Glucans; D008297:Male; D009270:Naloxone / Q000494:pharmacology*; D009292:Narcotic Antagonists / Q000494:pharmacology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D013213:Starch; D013395:Sucrose; D013649:Taste; D013997:Time Factors
chemical_list: D005936:Glucans; D009292:Narcotic Antagonists; D009270:Naloxone; D013395:Sucrose; D013213:Starch