RESUMO
Introduction: The study of food addiction (FA) has become relevant due to its high prevalence, the negative impact on quality of life, and its association with neuropsychological and psychiatric symptoms. Several studies have provided scientific support for these associations, however, the results are contradictory. Additionally, studies have unsuccessfully elucidated the true nature of the failures in executive functioning in people with FA symptomatology, particularly when it comes to executive deficits. Therefore, the purpose of this research was to establish whether the presence of executive dysfunction, depressive symptoms and binge eating problems, as well as high reward sensitivity entails a greater severity in FA traits and high body mass index (BMI) in a sample of Mexican adults. Methods: The sample consisted of Mexican men and women between 21-59 years (n = 36); who completed self-report questionnaires and performance tests to measure the study variables. Additionally, BMI was estimated with self-reported height and weight. Results: Our results showed that a high number of FA symptoms were associated with higher executive dysfunction scores, greater reward sensitivity, and more severe depressive and binge eating problems. Furthermore, factors that are more strongly associated with higher scores of FA include severe executive deficits, greater activation of the punishment avoidance system, and persistence in the search for reward when the depressive symptoms increased. The factors that best explained changes in the estimated BMI of women were a decreased crystallized intellectual capacity and the inability to control food intake as the number of FA symptoms increased. Discussion: In summary, the cognitive functioning profile characterized by general failure of the executive functioning, as well as a greater activation of the Punishment Avoidance System and persistence in the search for reward, were associated with greater severity of FA symptoms, especially when the depressive symptomatology was severe. In parallel, the psychopathology in participants associated with FA confirms the contribution of anxious and depressive symptomatology and borderline personality traits which could facilitate the expression of clinically relevant FA symptoms in women. Finally, we found that decreased crystallized intellectual capacity and inability to control food intake were linked to higher BMI when the number of FA symptoms increased.
Assuntos
Bulimia , Dependência de Alimentos , Adulto , Masculino , Humanos , Feminino , Dependência de Alimentos/epidemiologia , Dependência de Alimentos/psicologia , Depressão/epidemiologia , Depressão/psicologia , Prevalência , Qualidade de Vida , Função Executiva/fisiologia , Bulimia/psicologiaRESUMO
Resumen Se reconoce la participación de la oxitocina en el control de la alimentación, pero su mecanismo de acción no se ha establecido totalmente. Por tanto, el objetivo de esta investigación fue evaluar el efecto del acceso intermitente a una solución de sacarosa, sobre la expresión de las neuronas del núcleo paraventricular (PVN) y del núcleo supraótico (SON) que producen oxitocina (Oxt), y caracterizar la microestructura de la conducta de beber en ratas saciadas. Se tuvieron tres grupos de ratas macho Wistar saciadas, y en la primera hora al inicio del periodo de luz, el grupo Control tuvo agua, el grupo Restringido 5g de una solución de sacarosa al 20% y el grupo Ad libitum acceso libre a la solución de sacarosa. Los sujetos incrementaron el consumo de la solución de sacarosa a pesar de estar saciados; debido a la interrupción del estado de saciedad y la demora de la satisfacción. La actividad de las neuronas de Oxt se incrementó en ambos núcleos, en el grupo Restringido la mayor expresión se observó en el SON y en el grupo Ad libitum en el PVN. No se encontró correlación entre la cantidad de bebida ingerida y la actividad de las neuronas Oxt.
Abstract The role of oxytocin in feeding control is recognized, but its mechanism of action has not been fully established. Therefore, the aim of this research was to evaluate the effect of intermittent access to a sucrose solution on the expression of paraventricular nucleus (PVN) and supraotic nucleus (SON) neurons that produce oxytocin (Oxt), and to characterize the microstructure of drinking behavior in satiated rats. Three groups of male Wistar rats satiated were used, and in the first hour at the beginning of the light period, a Control group had water, a Restricted group 5g of a 20% sucrose solution and Ad libitum group with free access to sucrose solution. The experimental subjects increased the consumption of the sucrose solution despite being satiated, due to the interruption of the state of satiety and the delay of the satiation process. Oxt neurons increased their activity in both nuclei, in the Restricted group the highest expression was observed in the SON and in the Ad libitum group in the PVN. No correlation was found between the amount of drink ingested and the activity of Oxt neurons.
RESUMO
Resumen La obesidad y el sobrepeso son problemas de origen multifactorial, la interacción de los factores ambientales, genéticos y conductuales parecen ser la clave en el desarrollo de esta patología. Los receptores MC3 (rMC3) y MC4 (rMC4), participan en la regulación del balance energético (consumo de alimento, gasto energético y peso corporal), su mutación genética está asociada con el incremento de la adiposidad y el desarrollo de la obesidad. El conocimiento que se tiene de estos receptores y su función aún es limitado, principalmente con respecto a los rMC3 y, aunque los rMC4 se están posicionando como un blanco terapéutico potencial para el tratamiento de la obesidad, se requiere de mayor investigación clínica. Por lo tanto, el propósito de este documento es presentar evidencia de la participación de los receptores MC3 y MC4 en el desarrollo de la obesidad, a través de los resultados encontrados en algunas investigaciones, tanto en modelos animales como en humanos.
Abstract Obesity and overweight are problems of multifactorial origin, the interaction of environmental, genetic, and behavioral factors seems to be the key in the development of this pathology. The MC3 (rMC3) and MC4 (rMC4) receptors participate in the regulation of energy balance (food intake, energy expenditure and body weight), their genetic mutation is associated with increased adiposity and the development of obesity. Knowledge of these receptors and their function is still limited, mainly with respect to rMC3 and, although rMC4 are positioning themselves as a potential therapeutic target for the treatment of obesity, further clinical research is required. Therefore, the purpose of this document is to present the participation of MC3 and MC4 receptors in the development of obesity, through the results found in some investigations, both in animal and in human´s models.
RESUMO
Abstract Excessive consumption of high-fat food has been associated with increased prevalence of obesity. The physiological and metabolic effects of high-fat diets have been extensively studied. Nevertheless, the behavioral mechanisms associated with the development of obesity induced by consumption of these diets has been less explored. Therefore, the aim of the present study was to characterize the changes in the behavioral feeding patterns produced by the consumption of a high-fat diet during 10 days. Male Wistar rats with free access to food were assigned to one of two groups, and for 10 days, they had access to a high-fat diet (45 % calories from fat) or to a standard diet. Detailed analysis of feeding behavior was performed on days 1, 5 and 10 at the beginning of the dark period. The results showed that subjects exposed to the high-fat diet accumulated more body fat and showed increased feeding efficiency, in absence of excessive body weight increase or alterations in the behavioral satiety sequence pattern. These findings suggest that exposure to high-fat diets may produce behavioral changes before excessive gain of body weight occurs, primarily affecting control mechanisms of feeding efficiency.
Resumo O consumo excessivo de alimentos com alto conteúdo de gordura tem sido associado com o aumento da obesidade. Os efeitos fisiológicos e metabólicos do consumo de dietas altas em gordura têm sido estudados extensamente, contudo os mecanismos comportamentais relacionados com o desenvolvimento da obesidade pelo consumo dessas dietas têm-se explorado em menor medida. Portanto, o objetivo deste estudo foi caracterizar as mudanças nos padrões comportamentais da alimentação produzidas pelo consumo de uma dieta alta em gordura durante dez dias. Utilizaram-se ratos de laboratório macho Wistar, com acesso livre ao alimento, designados a um de dois grupos, e durante dez dias estiveram sob uma dieta alta em gordura (45 % de calorias provenientes de gorduras) ou uma dieta padrão de laboratório. Nos dias 1, 5 e 10, realizou-se uma análise detalhada do comportamento alimentar ao início do período de escuridão. Os resultados mostraram que os sujeitos expostos à dieta alta em gordura acumularam mais gordura corporal e tiveram maior eficiência da alimentação do que o outro grupo, sem aumento do peso corporal nem alterações do padrão da sequência de saciedade comportamental. Isso sugere que a exposição a dietas com alto conteúdo de gordura pode produzir mudanças comportamentais antes de apresentar um ganho de peso excessivo, o que afeta principalmente os mecanismos de controle de eficiência alimentar.
Resumen El consumo excesivo de alimentos con alto contenido de grasas se ha asociado con el incremento de la obesidad. Los efectos fisiológicos y metabólicos del consumo de dietas altas en grasa han sido estudiados extensamente; sin embargo, los mecanismos conductuales asociados al desarrollo de la obesidad por el consumo de estas dietas se han explorado en menor medida. Por tanto, el objetivo del presente estudio fue caracterizar los cambios en los patrones conductuales de la alimentación producidos por el consumo de una dieta alta en grasas durante diez días. Se utilizaron ratas macho Wistar con acceso libre al alimento, asignadas a uno de dos grupos, y durante diez días estuvieron bajo una dieta alta en grasa (45 % de calorías provenientes de grasas) o una dieta estándar de laboratorio. En los días 1, 5 y 10 se realizó un análisis detallado de la conducta alimentaria al inicio del periodo de oscuridad. Los resultados mostraron que los sujetos expuestos a la dieta alta en grasa acumularon más grasa corporal y tuvieron mayor eficiencia de la alimentación que el otro grupo, sin incremento del peso corporal ni alteraciones del patrón típico de la secuencia de saciedad conductual. Esto sugiere que la exposición a dietas con alto contenido de grasas puede producir cambios conductuales antes de que se presente una ganancia de peso excesivo, lo que afecta principalmente los mecanismos de control de eficiencia alimentaria.
Assuntos
Humanos , Masculino , Feminino , Adulto Jovem , Saciação , Peso Corporal , Tecido Adiposo , Dieta , Comportamento AlimentarRESUMO
El objetivo de la presente investigación fue evaluar el efecto de la estimulación de los receptores CRH2 del núcleo paraventricular hipotalámico sobre la ingesta de alimento y la expresión de la secuencia de saciedad conductual (SSC) en ratas adrenalectomizadas. Se trabajó con ocho grupos independientes de ratas Wistar, cuatro grupos adrenalectomizados (ADX) y cuatro con falsa cirugía. A todos los sujetos se les implantó una cánula en el núcleo paraventricular hipotalámico, y se les administró uno de cuatro tratamientos: vehículo, urocortina 2 (UCN2, agonista de CRH2), antisauvagina 30 (antagonista de CRH2), y antisauvagina-30 + UCN2 (pretratamiento). La administración de UCN2 redujo la ingesta de hidratos de carbono y de grasas en las ratas ADX, debido a la interrupción de la SSC; mientras que en las ratas con falsa cirugía, la UCN2 solo disminuyó la ingesta de grasas, debido al adelanto de la SSC. El pretratamiento previno los efectos inducidos en las ratas ADX, pero no en las ratas con falsa cirugía. Estos resultados indican que los receptores CRH2 modularon la ingesta y la SSC en las ratas ADX, lo que constituye un aporte importante en la comprensión de la etiología de la anorexia y del patrón conductual asociado a esta.
The objective of this research was to evaluate the effect of stimulation of receptors CRH2 in the paraventricular nucleus of the hypothalamus on food intake and expression of behavioral satiety sequence (BSS) in adrenalectomized rats. Eight independent groups of Wistar rats were utilized; four adrenalectomized groups (ADX) and four were false surgery. All subjects were implanted with a cannula in the paraventricular nucleus of the hypothalamus and were administered with one of the four treatments: vehicle, urocortin-2 (UCN2, CRH2 agonist), antisauvagine-30 (CRH2 antagonist) or antisauvagine-30 + UCN2 (pretreatment). UCN2 administration reduced intake of carbohydrates and fats in ADX rats due to the interruption of the BSS. In rats with false surgery it decreased fat intake due to the advancement of the BSS. Pretreatment prevented the effects induced by UCN2 in ADX rats but not in rats with false surgery. These results suggest that receptors CRH2 modulated intake and BSS in ADX rats, contributing with relevant information for the understanding of the anorexic ethiology and the behavioral pattern associated to it.
RESUMO
Obesity and its related pathologies are well- known health hazards. Although obesity and overweight have multifactorial causes, overeating is common in both of these conditions. According to animal models, endocannabinoids and their receptors in the brain play a key role in the genesis and development of obesity. It has been proposed that the cannabinoid receptors CB1 (RCB1) expressed in the nucleus accumbens shell (NAC) are involved in the increase of the hedonic properties of food. To test this hypothesis, this study aimed to assess the effects of activating the NACs RCB1 on standard food intake during the light phase of the light-dark cycle. The effects of activating the RCB1 with CP 55,940 and WIN 55-212-2 (0.125, 0.25 and 0.5 nmol) in the NACS on feeding behavior and the behavioral satiety sequence of rats were assessed. It was found that both agonists increased food intake and delayed expression of satiety during the light phase. These results suggest that cannabinoid agonists encourage food intake when motivation is low and palatability is normal.
La obesidad y sus patologías relacionadas son riesgos de salud muy conocidos. Aunque la obesidad y el sobrepeso tienen causas multifactoriales, la sobreingesta de alimento es frecuente en estas condiciones. De acuerdo con modelos animales, los endocanabinoides y sus receptores en el cerebro juegan un papel clave en la génesis y desarrollo de la obesidad. Se ha propuesto que los receptores a canabinoides CB1 (RCB1) expresados en el núcleo accumbens shell (NAcS) están involucrados en el incremento de las propiedades hedónicas del alimento. Para probar esta hipótesis, este estudio tuvo como objetivo evaluar los efectos de la activación de los RCB1 en el NAcS sobre la ingesta de alimento estándar durante la fase de luz del ciclo luz-oscuridad. Se evaluaron los efectos de la activación de los RCB1 con WIN 55-212-2 y CP 55,940 (0.125, 0.25, y 0.5 nmol) en el NAcS sobre la conducta alimentaria y la secuencia de saciedad conductual en ratas. Se encontró que ambos agonistas aumentaron la ingesta de alimento y demoraron la expresión de la saciedad durante la fase de luz. Lo anterior sugiere que los agonistas canabinoides estimulan el consumo de alimento cuando la motivación por el mismo es baja y la palatabilidad es normal.
A obesidade e suas patologias relacionadas são riscos de saúde muito conhecidos. Ainda que a obesidade e o sobrepeso possuam causas multifatoriais, a sobre ingestão de alimento é frequente nestas condições. De acordo com modelos animais, os endocanabinóides e seus receptores no cérebro jogam um papel chave na gênese e desenvolvimento da obesidade. Foi proposto que os receptores a canabinóides CB1 (RCB1) expressos no núcleo accumbens shell (NAcS) estão envolvidos no aumento das propriedades hedônicas do alimento. Para testar esta hipótese, este estudo teve como objetivo avaliar os efeitos da ativação dos RCB1 nos NAcS sobre a ingestão de alimento padrão durante a fase de luz do ciclo luz-escuridão. Avaliaram-se os efeitos da ativação dos RCB1 com WIN 55-212-2 e CP 55,940 (0.125, 0.25, e 0.5 nmol) no NAcS sobre a conduta alimentar e a sequência de saciedade condutual em ratos. Encontrou-se que ambos agonistas aumentaram a ingestão de alimento e demoraram a expressão da saciedade durante a fase de luz. Isso sugere que os agonistas canabinóides estimulam o consumo de alimento quando a motivação pelo mesmo é baixa e a palatabilidade é normal.
Assuntos
Humanos , Masculino , Feminino , Saciação , Canabinoides , Núcleo AccumbensRESUMO
Obesity is a serious worldwide health problem, affecting 20-40% of the population in several countries. According to animal models, obesity is related to changes in the expression of proteins that control energy homeostasis and in neurotransmission associated to regulation of food intake. For example, it has been reported that diet-induced obesity produces overexpression of dopamine D4 receptor (D4R) mRNA in the ventromedial hypothalamic nucleus (VMH) of mice. Neurons in the VMH send dense glutamatergic projections to other hypothalamic regions as the paraventricular nucleus (PVN), where multiple signals are integrated to finely regulate energy homeostasis and food intake. Although it is well established that dopaminergic transmission in the hypothalamus plays a key role in modulating feeding, the specific mechanisms involved in the activation of D4R in the PVN and its modulatory action on glutamate release and feeding behavior have remained unexplored. To fill this gap, we characterize the behavioral and neurochemical role of D4R in the PVN. In behavioral experiments, we examined the effects of activation of dopamine D4 receptors in the PVN on food intake and on the behavioral satiety sequence in rats exposed to a food-restricted feeding program. In vitro experiments were conducted to study the effects of activation of dopamine D4 receptors on [(3)H]glutamate release and on plasma corticosterone in explants of the PVN. We found that activation of D4R in the PVN induced inhibition of glutamate release and stimulated food intake by inhibiting satiety. Furthermore, activation of D4R in the PVN decreased plasma levels of corticosterone, and this effect was reverted by NMDA. According to our findings, D4R in the PVN may be a target for the pharmacotherapy for obesity as well as eating disorder patients who show restrictive patterns and overweight.
Assuntos
Ácido Glutâmico/metabolismo , Hiperfagia/fisiopatologia , Núcleo Hipotalâmico Paraventricular/metabolismo , Receptores de Dopamina D4/metabolismo , Animais , Benzamidas/farmacologia , Corticosterona/sangue , Agonistas de Dopamina/farmacologia , Antagonistas de Dopamina/farmacologia , Interações Medicamentosas , Ingestão de Alimentos/efeitos dos fármacos , Jejum , Agonistas de Receptores de GABA-A/farmacologia , Ácido Glutâmico/farmacologia , Hiperfagia/induzido quimicamente , Masculino , Muscimol/farmacologia , Núcleo Hipotalâmico Paraventricular/efeitos dos fármacos , Piperazinas/farmacologia , Piridinas/farmacologia , Pirimidinas/farmacologia , Pirróis/farmacologia , Ratos , Ratos Wistar , Saciação/efeitos dos fármacos , Trítio/farmacocinéticaRESUMO
BACKGROUND: Feeding behavior is deeply affected by serotonergic neurotransmission. This regulatory activity is mediated mainly by specific 5-HT1/2 receptors, and the paraventricular nucleus (PVN) plays a key role in this phenomena. In order to reveal the involvement of 5-HT1A and 5-HT1B receptors in the paraventricular nucleus of the hypothalamus (PVN) on serotonin-induced hypophagia, we examined the effects of intra-PVN injections of serotonin in WAY 100635 or SB 216641-pretreated rats on the structure of feeding behavior. MATERIAL/METHODS: Male Wistar rats were kept at 21+/-1 degrees C with a 12 h light /dark cycle on a self-selection feeding paradigm, provided with freely available and separate sources of protein, carbohydrate, fat and water. Blockade of 5-HT1A or 5-HT1B receptors in the paraventricular nucleus was effected by WAY 100635 (2 microg) or SB-216641 (2 microg) pretreatment; ten minutes later, 5-HT (2 microg) was applied into the same nucleus, then food intake and meal patterns were measured in a 30-minute period. The behavioral test was conducted at the beginning of the dark phase. RESULTS: The suppressive effect of 5-HT on carbohydrate intake was blocked by both WAY 100635 and SB 216641 at the beginning of the active (dark) feeding period. CONCLUSIONS: The hypophagic effect induced by 5-HT requires activation of 5-HT1A and 5-HT1B receptors, and the specific contribution of these subtype receptors is different, since the 5-HT1A subtype showed higher behavioral selectivity.
Assuntos
Comportamento Alimentar/efeitos dos fármacos , Receptores de Serotonina/efeitos dos fármacos , Serotonina/farmacologia , Animais , Benzamidas/farmacologia , Carboidratos da Dieta/administração & dosagem , Gorduras na Dieta/administração & dosagem , Proteínas Alimentares/administração & dosagem , Ingestão de Alimentos/efeitos dos fármacos , Preferências Alimentares/efeitos dos fármacos , Injeções Intraventriculares , Masculino , Oxidiazóis/farmacologia , Núcleo Hipotalâmico Paraventricular/metabolismo , Núcleo Hipotalâmico Paraventricular/fisiologia , Piperazinas/farmacologia , Piridinas/farmacologia , Ratos , Ratos Wistar , Receptores de Serotonina/fisiologia , Serotonina/administração & dosagem , Serotonina/fisiologia , Antagonistas da Serotonina/farmacologia , Água/administração & dosagemRESUMO
Debido a la administración de muscimol en el HVM (hipotálamo ventromedial) la ingesta de carbohidratos y la ingesta total se incrementaron; conductualmente este aumento de la ingesta de alimento se caracterizó por el aumento del tiempo total, asociado a un incremento en la duración de los episodios alimentarios. La administración de baclofén en el HVM incrementó la ingesta de carbohidratos y la ingesta total, este aumento se caracterizó por episodios alimentarios menos frecuentes pero más largos. Se confirma que la estimulación de los receptores GABAA y GABAB en el HVM inducen la alimentación y se concluye que el sistema GABAérgico está involucrado en el control de la conducta alimenticia.