Effect of opioid antagonism on conditioned place preferences to snack foods.
Previous research has shown that food-deprived rats acquire conditioned place preferences (CPPs) to sweet liquids that are largely attenuated by the opioid antagonist naltrexone (NAL). This study determined if ad libitum Chow-fed rats can learn CPPs when given relatively brief exposures to different solid snack foods (SFs) -- one high in sugar (Froot Loops cereal: FL) vs. one high in fat (Cheetos: C). Two groups of 16 male rats were trained during 20-min sessions to eat either FL or C in one side of a three-chambered CPP apparatus vs. Chow in the opposite side on alternating days for 20 days. Rats ate considerably more SFs of both types than Chow during the conditioning sessions (SFs: about 23 kcal versus Chow: about 7 kcal). Ten-minute tests for CPPs in the absence of SFs showed that the time spent on SF-conditioned sides increased significantly compared to pre-conditioning tests. Analyses of variance for re-tested CCPs after 0.1, 1.0, 2.5, and 5.0mg/kg NAL showed dose-dependent suppressions of CPPs to both SFs. These data show that consuming sweet or fatty SFs can become reliably associated with environmental cues in the non-deprived state. The endogenous opioid system, which mediates hedonic aspects of palatable food intake, appears to mediate these learned associations.
Jarosz
Patricia A
PA
College of Nursing, Wayne State University, 5557 Cass Avenue, Detroit, MI 48202, USA. pjarosz@wayne.edu
Sekhon
Phawanjit
P
Coscina
Donald V
DV
D000704:Analysis of Variance; D000818:Animals; D003216:Conditioning, Operant; D008297:Male; D009271:Naltrexone / Q000008:administration & dosage; D009292:Narcotic Antagonists / Q000494:pharmacology*; D051381:Rats; D017207:Rats, Sprague-Dawley
D009292:Narcotic Antagonists; D009271:Naltrexone