Ethanol-conditioned flavor preferences compared with sugar- and fat-conditioned preferences in rats.
Rats can learn to prefer flavors paired with ethanol and various nutrients. The present study examined the relative strengths of flavor preferences conditioned by 5% ethanol and isocaloric solutions of 7.18% sucrose, 7.18% fructose, or 3.26% corn oil. In three experiments, nondeprived rats were trained with different flavored solutions (conditioned stimuli, CS) paired with intragastric (IG) infusions: a CS+E flavor paired with ethanol infusion, a second CS+ paired with a nutrient infusion, and a CS- paired with water infusion. In two-bottle tests, rats strongly preferred a sucrose-paired CS+S over the CS- and over the CS+E. The preference for the CS+E over CS- was weaker. These effects occurred when the rats drank substantially more CS+S than CS+E in training and when training intakes were matched. Similar results were obtained when the nutrient infusion was fructose or corn oil, except that preferences for the CS+F or CS+O over the CS+E were less pronounced than with CS+S. Consistent with the IG results, rats trained to drink flavored sucrose and ethanol solutions preferred the CS+S to CS+E in a flavored water test. These results confirm prior reports of ethanol-conditioned preferences but show that ethanol is less effective than other nutrients at isocaloric concentrations. The marked individual differences in ethanol-conditioned preferences may be related to the impact of the sugar or fat infusions on the reward evaluation of the ethanol-paired flavor.
Ackroff
Karen
K
Department of Psychology, Brooklyn College and the Graduate School of the City University of New York, 2900 Bedford Avenue, Brooklyn, NY 11210, USA. kackroff@gc.cuny.edu
Rozental
Dayna
D
Sclafani
Anthony
A
D000818:Animals; D003216:Conditioning, Operant / Q000187:drug effects*; D003314:Corn Oil / Q000008:administration & dosage; D003463:Cues; D000431:Ethanol / Q000008:administration & dosage*; D005518:Food Preferences / Q000187:drug effects*; D005632:Fructose / Q000008:administration & dosage; D007263:Infusions, Parenteral; D007441:Intubation, Gastrointestinal; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley; D012054:Reinforcement, Psychology; D013395:Sucrose / Q000008:administration & dosage*; D013649:Taste
D005632:Fructose; D000431:Ethanol; D013395:Sucrose; D003314:Corn Oil