INCREASED FLAVOR ACCEPTANCE AND PREFERENCE CONDITIONED BY THE POSTINGESTIVE ACTIONS OF GLUCOSE

In Experiment 1, rats were given daily 2-h access to chow and water an d 20-h access to flavored solutions (cherry or grape). On alternate da ys, one flavor (CS+) was paired with intragastric infusions of 16% glu cose and another flavor (CS-) with IG water. In subsequent choice test s, the rats strongly preferred (95%) the CS+ to the CS-. CS+ intake al so greatly exceeded CS- intake during one-bottle training sessions (71 vs. 18 g/20 h). This increased acceptance was due to both increased b out size and number. When CS+ was paired with IG water (extinction tes t), CS+ bout size declined to CS-levels, while CS+ bout number and tot al intake remained elevated. In Experiment 2, rats trained with sucros e octa acetate and citric acid solutions also showed increased CS+ acc eptance and preference in one- and two-bottle tests, respectively. The rats also consumed more CS+ than CS- during short-term (30 min/day) o ne-bottle tests and intraoral intake tests under both deprived and ad lib. feeding conditions. These results demonstrate that the postingest ive actions of glucose can condition substantial increases in flavor a cceptance as well as flavor preference. (C) 1998 Elsevier Science Inc.