title: Post-oral fat stimulation of intake and conditioned flavor preference in C57BL/6J mice: A concentration-response study.
abstract: Fat appetite is determined not only by orosensory (flavor) stimuli but also by the post-oral actions of dietary fat, which promote increased attraction to the flavors of high-fat foods. Experiment 1 presents a concentration-response analysis of how intragastric (IG) fat self-infusions stimulate intake and condition flavor preferences in C57BL/6J mice trained 1h/day. 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 1.6, 3.2, 6.4 or 12.8% Intralipid (IL, soybean oil) (Tests 1-3). Following additional CS- and CS+ training sessions, a two-bottle CS+ vs. CS- choice test was conducted without infusions. Infusions of 3.2-12.8% IL stimulated CS+ licking in the first test session and more so in subsequent test sessions, and also conditioned significant CS+ preferences. These effects were similar to those previously observed with isocaloric glucose infusions (8-32%). IG infusion of 1.6% IL stimulated intake slightly but did not condition a CS+ preference comparable to the actions of isocaloric 4% glucose. Experiment 2 compared these subthreshold IL and glucose concentrations with that of a 1.6% IL+4% glucose infusion. This mixture stimulated 1-h CS+ licking more rapidly but generated a preference similar to that of 1.6% IL. In 23h/day tests, however, the IL+glucose mixture stimulated greater CS+ intakes and preferences than did 1.6% IL or 4% glucose. These findings show that fat, like glucose, rapidly generates concentration-dependent post-oral signals that stimulate intake and enhance preferences for energy-rich foods in mice.
authors.affiliation: Department of Psychology, Brooklyn College, City University of New York, Brooklyn, NY 11210, USA; Cognition, Brain and Behavior Doctoral Subprogram, The Graduate School, City University of New York, New York, NY 10016, USA. Electronic address: kackroff@gc.cuny.edu.
authors.forename: Karen
authors.initials: K
authors.lastname: Ackroff
authors.affiliation: Department of Psychology, Brooklyn College, City University of New York, Brooklyn, NY 11210, USA; Cognition, Brain and Behavior Doctoral Subprogram, The Graduate School, City University of New York, New York, NY 10016, USA.
authors.forename: Anthony
authors.initials: A
authors.lastname: Sclafani
mesh_terms: D000818:Animals; D001066:Appetite / Q000502:physiology; D003213:Conditioning, Psychological / Q000502:physiology*; D004041:Dietary Fats / Q000378:metabolism*; D019422:Dietary Sucrose / Q000378:metabolism; D004435:Eating / Q000502:physiology; D004655:Emulsions / Q000378:metabolism; D005518:Food Preferences / Q000502:physiology*; D005753:Gastric Mucosa / Q000378:metabolism*; D005947:Glucose / Q000378:metabolism; D008297:Male; D008810:Mice, Inbred C57BL; D010743:Phospholipids / Q000378:metabolism; D012439:Saccharin / Q000008:administration & dosage; D013024:Soybean Oil / Q000378:metabolism
chemical_list: D004041:Dietary Fats; D019422:Dietary Sucrose; D004655:Emulsions; D010743:Phospholipids; C545823:soybean oil, phospholipid emulsion; D013024:Soybean Oil; D012439:Saccharin; D005947:Glucose
keywords: Appetition; Glucose; Intragastric; Intralipid; Post-oral fat conditioning