RESUMO
PURPOSE: This study investigated the acute effect of anodal transcranial direct current stimulation (a-tDCS) over the left dorsolateral prefrontal cortex (DLPFC) on appetite, energy intake, food preferences, and mood states in the luteal and follicular phases of the menstrual cycle in women presenting premenstrual syndrome. METHODS: Sixteen women (26.5 ± 5.2 years; 1.63 ± 0.1 m; 64.2 ± 12.8 kg; body mass index 24.0 ± 5.0 kg/m2; body fat 27.6 ± 7.5%) with the eumenorrheic menstrual cycle were submitted to a-tDCS and sham-tDCS conditions over their follicular and luteal phases. At pre - and post-tDCS, hunger and desire to eat something tasty, (analogic visual scale), the profile of mood states (POMS), and the psychological components of food preferences (Leeds Food Preference Questionnaire-BR) were assessed. Participants recorded their food intake for the rest of the day using a diary log. RESULTS: There was a trend towards main effect of condition for decreased implicit wanting for low-fat savory food after a-tDCS but not sham-tDCS regardless of menstrual cycle phase (p = 0.062). There was no effect for self-reported hunger, desire to eat, energy and macronutrient intake, and on other components of food preferences (explicit liking and wanting for low- and high-fat savory and sweet foods, implicit wanting for low- and high-fat sweet and high-fat savory food); as well as for mood states. CONCLUSIONS: Although no significant effects of a-tDCS were found, the present investigation provides relevant perspectives for future studies.
Assuntos
Síndrome Pré-Menstrual , Estimulação Transcraniana por Corrente Contínua , Humanos , Feminino , Apetite/fisiologia , Ingestão de Alimentos/psicologia , Síndrome Pré-Menstrual/terapia , Síndrome Pré-Menstrual/psicologia , Ciclo Menstrual , Córtex Pré-Frontal/fisiologiaRESUMO
ß-caryophyllene (BCP) is a cannabinoid receptor CB2 agonist plant-derived terpenoid found in different essential oil plants, including rosemary, black pepper, copaiba and cannabis. It has GRAS (generally recognized as safe) status and is approved by the FDA (Food and Drug Administration) for food use. BCP displays agonist activity on the CB2 receptor and is a potential therapeutic target in several neuropsychiatric disorders, including anxiety and drug addiction. Unlike CB1 receptors, activation of the CB2 receptors is devoid of psychotomimetic and addictive properties. In this regard, this study aimed to evaluate the effects of BCP on incentive salience ("wanting") performance and motivational properties elicited by sweetened palatable foods in female Swiss mice. After 9 days of training for incentive salience performance for a sweet reward (hazelnut cream with chocolate), food-restricted mice received a systemic injection of BCP (50 and 100 mg/kg) before testing over 3 days. Moreover, independent groups of female mice were tested on sweet reward-induced conditioned place preference (CPP) for 22 consecutive days. To evaluate BCP effects on the expression of seeking behaviour for sweetened food, mice received a single intraperitoneal injection of BCP (50 mg/kg) 30 min before testing on the CPP task. BCP significantly decreased the incentive performance for a sweet reward compared with the control group in a CB2 receptor-dependent manner. Also, BCP suppressed the expression of sweet reward-CPP. Altogether, these preclinical data demonstrate the potential role of BCP in treating disorders associated with food addiction-like behaviour.
Assuntos
Sesquiterpenos , Camundongos , Animais , Sesquiterpenos/farmacologia , Agonistas de Receptores de Canabinoides/farmacologia , Motivação , Receptor CB2 de Canabinoide , Receptor CB1 de CanabinoideRESUMO
The Power of Food Scale (PFS) is a questionnaire for self-assessing the motivation to consume palatable foods, especially in environments where food is abundant and constantly available. This study aimed to a) assess the factorial structure of the PFS in a Brazilian sample and b) examine the relationship between the power of food and body image dissatisfaction and BMI. The PFS and Body Shape Questionnaire (BSQ) were applied to a sample of 300 adults. Data were analysed using confirmatory factor analysis. Composite reliability (CR) was used to verify factor reliability. A partial least squares structural equation model was used to verify the effect of the PFS score on body image dissatisfaction. The PFS had an adequate factorial structure in this Brazilian sample, showing three well-defined factors: food available (CRâ¯=â¯0.91), food tasted (CRâ¯=â¯0.84), and food present (CRâ¯=â¯0.87). The BSQ showed one reliable factor (CRâ¯=â¯0.97). The power of the food aggregate factor significantly predicted body mass index (ßâ¯=â¯0.16; pâ¯=â¯.01) and body image dissatisfaction (ßâ¯=â¯0.46; pâ¯<â¯.001). The effect size was small for body mass index (f2â¯=â¯0.02) and medium for body image dissatisfaction (f2â¯=â¯0.26). The food present factor also had a slightly higher average among the three PFS factors. Women had higher PFS scores than men. Understanding the role that this motivation plays in physical and psychological outcomes such as body dissatisfaction can contribute to developing treatment strategies and support health professionals' performance in clinical settings.
Assuntos
Imagem Corporal , Motivação , Adulto , Índice de Massa Corporal , Brasil , Comportamento Alimentar/psicologia , Feminino , Humanos , Masculino , Reprodutibilidade dos Testes , Inquéritos e QuestionáriosRESUMO
Most living organisms have a circadian timing system adapted to optimize the daily rhythm of exposure to the environment. This circadian system modulates several behavioral and physiological processes, including the response to natural and drug rewards. Food is the most potent natural reward across species. Food-seeking is known to be mediated by dopaminergic and serotonergic transmission in cortico-limbic pathways. In the present work, we show evidence of a circadian modulation of motivation for food reward in young (4-months old) and aged (over 1.5 years old) C57BL/6 mice. Motivation was assayed through the progressive ratio (PR) schedule. Mice under a 12:12 light/dark (LD) cycle exhibited a diurnal rhythm in motivation, becoming more motivated during the night, coincident with their active phase. This rhythm was also evident under constant dark conditions, indicating the endogenous nature of this modulation. However, circadian arrhythmicity induced by chronic exposure to constant light conditions impaired the performance in the task causing low motivation levels. Furthermore, the day/night difference in motivation was also evident even without caloric restriction when using a palatable reward. All these results were found to be unaffected by aging. Taken together, our results indicate that motivation for food reward is regulated in a circadian manner, independent of the nutritional status and the nature of the reward, and that this rhythmic modulation is not affected by aging. These results may contribute to improve treatment related to psychiatric disorders or drugs of abuse, taking into account potential mechanisms of circadian modulation of motivational states.
Assuntos
Ritmo Circadiano , Motivação/fisiologia , Recompensa , Animais , Condicionamento Operante , Masculino , Camundongos Endogâmicos C57BLRESUMO
The growth hormone secretagogue receptor (GHSR) is a G protein-coupled receptor that is highly expressed in the central nervous system. GHSR acts as a receptor for ghrelin and for liver-expressed antimicrobial peptide 2 (LEAP2), which blocks ghrelin-evoked activity. GHSR also displays ligand-independent activity, including a high constitutive activity that signals in the absence of ghrelin and is reduced by LEAP2. GHSR activity modulates a variety of food intake-related behaviours, including binge eating. Previously, we reported that GHSR-deficient mice daily and time-limited exposed to a high-fat (HF) diet display an attenuated binge-like HF intake compared to wild-type mice. In the present study, we aimed to determine whether ligand-independent GHSR activity affects binge-like HF intake in a 4-day binge-like eating protocol. We found that plasma levels of ghrelin and LEAP2 were not modified in mice exposed to this binge-like eating protocol. Moreover, systemic administration of ghrelin or LEAP2 did not alter HF intake in our experimental conditions. Interestingly, we found that central administration of LEAP2 or K-(D-1-Nal)-FwLL-NH2 , which are both blockers of constitutive GHSR activity, reduced binge-like HF intake, whereas central administration of ghrelin or the ghrelin-evoked GHSR activity blockers [D-Lys3]-GHRP-6 and JMV2959 did not modify binge-like HF intake. Taken together, current data indicate that GHSR activity in the brain affects binge-like HF intake in mice independently of plasma levels of ghrelin and LEAP2.
Assuntos
Peptídeos Catiônicos Antimicrobianos/fisiologia , Bulimia/fisiopatologia , Grelina/fisiologia , Receptores de Grelina/agonistas , Receptores de Grelina/fisiologia , Animais , Peptídeos Catiônicos Antimicrobianos/administração & dosagem , Peptídeos Catiônicos Antimicrobianos/sangue , Peptídeos Catiônicos Antimicrobianos/farmacologia , Bulimia/prevenção & controle , Dieta Hiperlipídica , Grelina/administração & dosagem , Grelina/sangue , Grelina/farmacologia , Glicina/análogos & derivados , Glicina/farmacologia , Infusões Intraventriculares , Masculino , Camundongos , Oligopeptídeos/farmacologia , Receptores de Grelina/antagonistas & inibidores , Fatores de Tempo , Triazóis/farmacologiaRESUMO
The Leeds Food Preference Questionnaire (LFPQ) measures separable psychological components of food reward (Liking and Wanting). In this study a cultural adaptation of the LFPQ for a Brazilian population (LFPQ-BR) was examined by comparing liking and wanting scores in fasted and fed states and their association with adiposity and disturbed eating. A culturally adapted food picture database was validated by an online questionnaire completed by 162 individuals. Cluster analysis verified if the foods were accurately perceived in terms of sweetness, fat and calorie content. Subsequently, 48 male (Nâ¯=â¯21) and female (Nâ¯=â¯27) adults with mean Body Mass Index 26.6 (0.9) kg/m2, and mean age 32.8 (1.4) years, were evaluated by the LFPQ-BR before and after a fixed test meal. The Binge Eating Scale was used to measure binge eating symptoms. There was a decrease in explicit liking, implicit wanting, and explicit wanting scores for food in general in the fed condition. The implicit and explicit wanting and explicit liking scores for high-and-low fat savoury food decreased and for high-and-low fat sweet foods increased to a greater extent after the savoury test meal. Body Mass Index was found to predict implicit wanting for high fat relative to low fat foods. Binge eating symptoms predicted high fat sweet explicit liking and explicit wanting in the fed condition. Finally, high fat sweet preference was found to be sex-related as females had greater implicit wanting for high fat sweet foods in fasted and fed states. The results presented here indicate that the LFPQ-BR is a useful instrument for the evaluation of liking and wanting for food in Brazil.
Assuntos
Adiposidade , Bulimia/psicologia , Preferências Alimentares/psicologia , Inquéritos e Questionários , Adulto , Índice de Massa Corporal , Brasil , Características Culturais , Gorduras na Dieta , Feminino , Humanos , Masculino , Paladar , TraduçõesRESUMO
Binge eating is a behavior observed in a variety of human eating disorders. Ad libitum fed rodents daily and time-limited exposed to a high-fat diet (HFD) display robust binge eating events that gradually escalate over the initial accesses. Intake escalation is proposed to be part of the transition from a controlled to a compulsive or loss of control behavior. Here, we used a combination of behavioral and neuroanatomical studies in mice daily and time-limited exposed to HFD to determine the neuronal brain targets that are activated--as indicated by the marker of cellular activation c-Fos--under these circumstances. Also, we used pharmacologically or genetically manipulated mice to study the role of orexin or ghrelin signaling, respectively, in the modulation of this behavior. We found that four daily and time-limited accesses to HFD induce: (i) a robust hyperphagia with an escalating profile, (ii) an activation of different sub-populations of the ventral tegmental area dopamine neurons and accumbens neurons that is, in general, more pronounced than the activation observed after a single HFD consumption event, and (iii) an activation of the hypothalamic orexin neurons, although orexin signaling blockage fails to affect escalation of HFD intake. In addition, we found that ghrelin receptor-deficient mice fail to both escalate the HFD consumption over the successive days of exposure and fully induce activation of the mesolimbic pathway in response to HFD consumption. Current data suggest that the escalation in high fat intake during repeated accesses differentially engages dopamine neurons of the ventral tegmental area and requires ghrelin signaling.
Assuntos
Bulimia/fisiopatologia , Dieta Hiperlipídica/efeitos adversos , Neurônios Dopaminérgicos/efeitos dos fármacos , Grelina/fisiologia , Área Tegmentar Ventral/efeitos dos fármacos , Animais , Antecipação Psicológica/efeitos dos fármacos , Feminino , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Atividade Motora/efeitos dos fármacos , Núcleo Accumbens/citologia , Núcleo Accumbens/metabolismo , Orexinas/fisiologia , Proteínas Proto-Oncogênicas c-fos/metabolismo , Transdução de Sinais/efeitos dos fármacos , Área Tegmentar Ventral/citologia , Área Tegmentar Ventral/metabolismoRESUMO
Highly palatible foods may induce addiction-related behaviors. However, this has yet to be established in non-human primates. Therefore, we evaluated whether marmoset monkeys (Calllithrix penicillata) acquire a conditioned-place-preference (CPP) for chocolate and if this response is detectable after a 24-h and 15-day period. Subjects were first habituated to a two-compartment CPP box and then randomly assigned to a chocolate or control group. Thereafter, they were given access to only one compartment during daily 15-min conditionings, held on six consecutive days. On each trial, the chocolate group received pieces of chocolate (50g) in this context, whereas controls were not given a food reward. Marmosets were subsequently tested for preferring this (food) paired context after a 24-h and 15-day interval. During conditioning, individual foraging and the amount of chocolate ingested by each pair of the chocolate group remained constant. However, compared to pre-CPP levels, the time spent inside/in contact with the conditioned compartment increased significantly, while the latency to first entry decreased on both post-CPP intervals. For controls, the parameters remained unaltered. Thus, chocolate induced a persistent CPP response-an aspect usually associated with drug-related rewards.
Assuntos
Cacau , Callithrix/fisiologia , Condicionamento Psicológico/fisiologia , Comportamento Alimentar/fisiologia , Memória de Longo Prazo/fisiologia , Recompensa , Animais , Feminino , Masculino , Distribuição AleatóriaRESUMO
Time can be an important contextual cue for cognitive performance, with implications for reward-associated learned behaviors such as (drug and food) addiction. So, we analyzed: (1) if marmoset monkeys develop a place preference that is conditioned to previous pairings with a highly-palatable food reward; (2) if the response is strongest when training and testing times match - time stamp effect; and (3) if there is an optimal time of the day (morning vs. afternoon) when this preference occurs - time-of-day effect. Subjects were first habituated to a two-compartment conditioned-place-preference (CPP) box. Then, during six training sessions held either in the morning or afternoon, a mixture of jellybeans and live mealworms was made available in a specific compartment. Marmosets were subsequently tested for preferring the food-paired context at the circadian time that either matched or was different from that of training. Compared to baseline levels, only subjects trained and tested in the afternoon made significantly longer and more frequent visits to the food-paired context and with a shorter latency to first entry. Thus, highly-palatable food rewards induced a CPP response. This behavior was exhibited only when training and testing times overlapped and during a restricted circadian timeframe (afternoon), consistent with a time-stamp and time-of-day effect, respectively. In this case, time may have been an internal circadian contextual cue. Whether due to circadian-mediated oscillations in memory and/or reward processes, such findings may be applied to addiction and other learned behaviors.