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Type:	Dissertação
Title:	Evaluation of binge eating behaviour induced by intermittent access to High Sugar and Butter (HSB) diet in C57BL/6
Authors:	Agatha Sondertoft Braga Pedersen
First Advisor:	Ana Lucia Brunialti Godard
First Referee:	Erika Cristina Jorge
Second Referee:	Bruno Resende de Souza
Abstract:	It is known that high palatable food interacts with the complex systemic and neural systems that regulate hunger and satiety, and that it can culminate in the loss of control over food consumption, the core diagnose of binge eating disorder. Despite this fact, little is known about the neurobiology of this phenotype. The prefrontal cortex, which is part of the reward system of the brain, plays important roles in the control of impulsivity and goal-directed actions, which places it as an important target that could potentiate food seeking and contribute to the establishment of this disorder. The present work aimed to evaluate the binge eating behaviour induced by intermittent access to High Sugar and Butter (HSB) diet in C57BL/6 and also to evaluate how this phenotype affects anxiety and memory of mice as well as the transcriptional regulation of dopaminergic, GABAergic receptors in the prefrontal cortex of animals. To address these issues, two experiments were set (one of 4 weeks and one of 8 weeks). Upon arrival, male mice were divided in 3 groups: CHOW-d (that had daily access to maintenance diet), HSB-i (that had daily access to maintenance diet and 3 times a week had access to HSB) and HSB-d (that had daily access to HSB). In the last week of each experiment, animals were submitted to three behavioural tests: marble-burying test, light dark box and a repetition of the light dark box with the exception of the presence of food pellets in the light zone. In addition, in the 6th week of the 8 week experiment, animals were submitted to the novel object recognition test. Food consumption and bodyweight were measured throughout the experiment. The Prefrontal Cortex was collected for transcriptional analysis of Drd1, Drd2, Gabbr1, Gabbr2 and Bdnf by qPCR and western blot analysis. The results showed that the HSB-i group established a pattern of food intake in which mice consumed significantly more kilocalories than the other groups on the days that HSB was available, and significantly fewer kilocalories on the complementary days. In all accesses days, this group also ingested significantly higher quantities of kilocalories in comparison with the other groups in the period of 2h and this consumption represented most of total 24h energy consumption (i.e. last access day, it represented 91%). Over the course of the time, binge episodes intensified and got more severe, which could be an indicative of reduced sensitivity and tolerance. Despite this large consumption by the HSB-i group, only the HSB-d group gained weight and increased adipose index throughout the experiment. In the 4 week experiment, HSB-i group showed a high motivational drive to obtain food, while chronic consumption of this diet induced an anxiolytic effect in HSB-d group, but these behaviors did not repeat after 4 more weeks of experiment, which could be related with environmental influences. No differences were found in the novel object recognition test. Despite the clear and severe binge eating phenotype achieved, only a downregulation of Drd1 gene in prefrontal cortex of animals after 8 weeks of experiment was found. This result could be an indicative of a dopaminergic hypoactivity in this region, a reflex of other reward regions dopaminergic modulation, or also that in this binge eating protocol, the phenotype is not driven by dopaminergic and GABAergic alterations in the prefrontal cortex. Nevertheless, a replication of this study is mandatory to confirm these assumptions.
Subject:	Genética Transtorno da Compulsão Alimentar Camundongos Endogâmicos C57BL Córtex Pré-Frontal Dieta
language:	eng
metadata.dc.publisher.country:	Brasil
Publisher:	Universidade Federal de Minas Gerais
Publisher Initials:	UFMG
metadata.dc.publisher.department:	ICB - DEPARTAMENTO DE BIOLOGIA GERAL
metadata.dc.publisher.program:	Programa de Pós-Graduação em Genética
Rights:	Acesso Restrito
metadata.dc.rights.uri:	http://creativecommons.org/licenses/by-nc-nd/3.0/pt/
URI:	http://hdl.handle.net/1843/41600
Issue Date:	26-Feb-2019
metadata.dc.description.embargo:	26-Feb-2020
Appears in Collections:	Dissertações de Mestrado

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