title: Alterations in sucrose sham-feeding intake as a function of diet-exposure in rats maintained on calorically dense diets.
abstract: We previously reported that rats increase meal size upon initial presentation of a calorically dense diet. The increase may be attributed to increased orosensory stimulation and/or reduced sensitivity to post-ingestive inhibitory signals. During feeding both types of signals are simultaneously in play; thus here, we compare responses in rats presented a high-energy diet (HE) or 45% high-fat diet (HF) with those of chow-fed controls (CHOW) in a sham-feeding procedure in which post-ingestive feedback is minimized. Measures of sham-feeding to sucrose were taken before diet manipulation (baseline), ~5 days (dynamic phase) and ~6 weeks (static phase) following introduction of the palatable diet, as well as after animals were switched back to standard chow (recovery phase). Some but not all the hypotheses based on our previous findings were confirmed by the outcomes here. Consistent with our hypothesis that enhanced orosensory stimulation during the dynamic phase compared with the static phase would generalize to increased intake of other palatable stimuli, HE rats showed higher sucrose intake during the dynamic phase compared with the static phase. Contrary to what we hypothesized, HE and HF rats did not increase responses to sucrose compared to CHOW rats. In fact, HE rats showed decreased responses compared to CHOW controls. Thus changes in orosensory stimulation do not necessarily generalize to increased intake of other palatable stimuli.
authors.affiliation: Department of Psychiatry and Behavioral Sciences, School of Medicine, Johns Hopkins University, Ross 615, 720 Rutland Ave, Baltimore, MD, USA. Electronic address: yadatree@jhmi.edu.
authors.forename: Yada
authors.initials: Y
authors.lastname: Treesukosol
authors.affiliation: Department of Psychiatry and Behavioral Sciences, School of Medicine, Johns Hopkins University, Ross 615, 720 Rutland Ave, Baltimore, MD, USA.
authors.forename: Nu-Chu
authors.initials: NC
authors.lastname: Liang
authors.affiliation: Department of Psychiatry and Behavioral Sciences, School of Medicine, Johns Hopkins University, Ross 615, 720 Rutland Ave, Baltimore, MD, USA; Johns Hopkins Global Obesity Prevention Center, Johns Hopkins University, Baltimore, MD, USA.
authors.forename: Timothy H
authors.initials: TH
authors.lastname: Moran
mesh_terms: D000818:Animals; D001069:Appetite Regulation; D001522:Behavior, Animal; D059305:Diet, High-Fat / Q000009:adverse effects*; D019422:Dietary Sucrose / Q000008:administration & dosage / Q000009:adverse effects*; D004195:Disease Models, Animal; D002149:Energy Intake; D005518:Food Preferences; D006963:Hyperphagia / Q000209:etiology* / Q000503:physiopathology; D008297:Male; D009765:Obesity / Q000209:etiology*; D017207:Rats, Sprague-Dawley; D015430:Weight Gain
chemical_list: D019422:Dietary Sucrose
keywords: High fat; Oral; Palatability; Post-ingestive; Sweet; Taste