Flavor preferences conditioned by intragastric polycose in rats: more concentrated polycose is not always more reinforcing.
Prior studies have obtained conditioned preferences for flavors paired with intragastric (IG) infusions of Polycose (hydrolyzed starch) at concentrations of 1-32% over a different flavor paired with IG water. The present study determined if rats would also learn to prefer a flavor paired with concentrated Polycose infusion over a flavor paired with a more dilute Polycose infusion. In Experiment 1, adult female rats were food-deprived and trained during alternating one-bottle sessions (30 min/day) to associate one flavored solution (the CS + 8) with IG infusions of 8% Polycose, a second flavored solution (the CS + 16) with IG infusions of 16% Polycose, and a third flavored solution (the CS-) with IG water infusions. In subsequent choice tests, the rats displayed similar preferences for the CS + 8 and CS + 16 over the CS-, but preferred the CS + 16 to CS + 8 in a direct choice test. A similar preference pattern was obtained in 22 h/day tests with the rats nondeprived. In Experiment 2, new rats were similarly trained and tested but with CS + 16 and CS + 32 solutions paired with 16% and 32% Polycose infusions, respectively. The rats preferred both CS+ solutions over the CS- solution in the short- and long-term tests. However, the CS + 16 was preferred over the CS + 32 by the food-deprived rats in the short-term tests. The two CS+ solutions were equally preferred in the long-term tests with food ad lib. These and other findings indicate that the postingestive reinforcing action of Polycose increases as concentration increases from 1% to 16% but does not increase further, and may actually decrease, at a 32% concentration. The rapid satiating effect of concentrated carbohydrate solutions may limit their reinforcing consequences.
Lucas
F
F
Department of Psychology, Brooklyn College, City University of New York 11210, USA.
Azzara
A V
AV
Sclafani
A
A
D000284:Administration, Oral; D000818:Animals; D003216:Conditioning, Operant / Q000187:drug effects*; D004435:Eating / Q000187:drug effects; D004734:Energy Metabolism / Q000187:drug effects; D005260:Female; D005936:Glucans / Q000008:administration & dosage / Q000494:pharmacology*; D007441:Intubation, Gastrointestinal; D051381:Rats; D012054:Reinforcement, Psychology; D012528:Satiety Response / Q000187:drug effects; D013649:Taste / Q000187:drug effects / Q000502:physiology*
D005936:Glucans