title: Post-oral glucose stimulation of intake and conditioned flavor preference in C57BL/6J mice: a concentration-response study.
abstract: In a recent study, intragastric (IG) self-infusion of 16% glucose stimulated 1-h intake and conditioned a preference for a flavored saccharin solution in C57BL/6J mice (Zukerman et al., 2011). Experiment 1 of the present study presents a concentration-response analysis of IG glucose-induced intake stimulation monitored by recording licking response every min of the 1h/day sessions. Separate groups of food-restricted mice consumed a flavored saccharin solution (the CS-) paired with IG self-infusions of water (Test 0) followed by a different flavored solution (the CS+) paired with IG self-infusions of 2, 4, 8, 16, or 32% glucose (Tests 1-3). Following additional CS- and CS+ training sessions, a two-bottle CS+ vs. CS- choice test was conducted without infusions. Self-infusions of 8%, 16% or 32% glucose stimulated CS+ licking within 12 min of the first test session and even earlier in subsequent test sessions, and also conditioned significant CS+ preferences in the two-bottle test. The stimulation of early licking and CS+ preference increased as a function of glucose concentration. The amount of glucose solute self-infused increased with sugar concentration as did post-infusion blood glucose levels. The 2% glucose infusion did not stimulate CS+ intake and the 2% and 4% infusions failed to produce a CS+ preference in the 1-h test. Experiment 2 revealed that intraperitoneal self-infusions of 8% glucose, unlike IG glucose self-infusions, failed to stimulate CS+ licking or preference despite producing maximal increases in blood glucose levels. Taken together, these and other findings suggest that glucose rapidly produces concentration-dependent intestinal signals that stimulate intake and condition flavor preferences while post-oral satiation signals limit total amounts consumed.
authors.affiliation: Department of Psychology, Brooklyn College, City University of New York, Brooklyn, 11210, USA.
authors.forename: Steven
authors.initials: S
authors.lastname: Zukerman
authors.forename: Karen
authors.initials: K
authors.lastname: Ackroff
authors.forename: Anthony
authors.initials: A
authors.lastname: Sclafani
mesh_terms: D000284:Administration, Oral; D000704:Analysis of Variance; D000818:Animals; D003213:Conditioning, Psychological / Q000187:drug effects* / Q000502:physiology; D004305:Dose-Response Relationship, Drug; D004327:Drinking Behavior / Q000187:drug effects; D005421:Flavoring Agents / Q000008:administration & dosage*; D005518:Food Preferences / Q000187:drug effects / Q000502:physiology*; D005947:Glucose / Q000008:administration & dosage*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D012201:Reward; D012439:Saccharin / Q000008:administration & dosage*; D013549:Sweetening Agents / Q000008:administration & dosage*
chemical_list: D005421:Flavoring Agents; D013549:Sweetening Agents; D012439:Saccharin; D005947:Glucose