Premium
Arcuate Nucleus Homeostatic Systems are Not Altered Immediately Prior to the Scheduled Consumption of Large, Binge‐Type Meals of Palatable Solid or Liquid Diet in Rats and Mice
Author(s) -
Bake T.,
Duncan J. S.,
Morgan D. G. A.,
Mercer J. G.
Publication year - 2013
Publication title -
journal of neuroendocrinology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.062
H-Index - 116
eISSN - 1365-2826
pISSN - 0953-8194
DOI - 10.1111/jne.12008
Subject(s) - endocrinology , medicine , neuropeptide y receptor , arc (geometry) , meal , calorie , leptin , nucleus accumbens , liquid diet , biology , chemistry , obesity , neuropeptide , biochemistry , central nervous system , receptor , geometry , mathematics , ethanol
Meal feeding is a critical issue in the over‐consumption of calories leading to human obesity. To investigate the mechanisms involved in the regulation of meal feeding in rodents, we studied a scheduled feeding regime that induces substantial food intake over short periods of time. Male S prague– D awley rats and C 57 B L6 mice were fed one of four palatable diets [45% fat pellet, 60% fat pellet or standard pellet supplemented with Ensure (EN; Abbott Laboratories, Maidenhead, UK) or 12.5% sucrose (SUC)] either ad lib . or with daily 2‐h scheduled access and standard pellet available for 22 h. Energy balance gene expression in the hypothalamic arcuate nucleus ( ARC ) and nucleus accumbens ( NA cc) reward gene expression were assessed by in situ hybridisation. Rats fed ad lib . on 45% or 60% fat diet were heavier and fatter than controls, and had reduced neuropeptide Y ( NPY ) gene expression in the ARC . Mice fed ad lib . on any of the palatable diets were heavier, fatter and had higher blood leptin than controls, and had reduced NPY and increased cocaine‐ and‐amphetamine‐regulated transcript m RNA in the ARC . Schedule‐fed rats and mice quickly adapted their feeding behaviour to 2‐h access on palatable food. Three schedule‐fed groups binged: the percentage of daily calories consumed in 2 h on 45% fat diet, 60% fat diet or EN , respectively, was 55%, 63% and 49% in rats, and 86%, 86% and 45% in mice. However, changed feeding behaviour was not reflected in an induction of orexigenic neuropeptide or suppression of anorexigenic neuropeptide gene expression in the ARC , in the 2‐h period prior to scheduled feeding. The mechanisms underlying large meal/binge‐type eating may be regulated by nonhomeostatic processes involving other genes in the hypothalamus or other brain areas. However, assessment of opioid and dopamine receptor gene expression in the NA cc did not reveal evidence of the involvement of these genes in driving large meals, at least at the investigated time point.