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Journal of Psychopharmacology (Oxford,... Nov 2017Traditional models of appetite control have emphasised the role of parallel homeostatic and hedonic systems, but more recently the distinction between independent... (Review)
Review
Traditional models of appetite control have emphasised the role of parallel homeostatic and hedonic systems, but more recently the distinction between independent homeostatic and hedonic systems has been abandoned in favour of a framework that emphasises the cross talk between the neurochemical substrates of the two systems. In addition, evidence has emerged more recently, that higher level cognitive functions such as learning, memory and attention play an important role in everyday appetite control and that homeostatic signals also play a role in cognition. Here, we review this evidence and present a comprehensive model of the control of appetite that integrates cognitive, homeostatic and reward mechanisms. We discuss the implications of this model for understanding the factors that may contribute to disordered patterns of eating and suggest opportunities for developing more effective treatment approaches for eating disorders and weight management.
Topics: Animals; Appetite; Appetite Regulation; Body Weight; Cognition; Eating; Humans; Reward
PubMed: 29072515
DOI: 10.1177/0269881117736917 -
Nutrients Aug 2018Exercise facilitates weight control, partly through effects on appetite regulation. Single bouts of exercise induce a short-term energy deficit without stimulating... (Review)
Review
Exercise facilitates weight control, partly through effects on appetite regulation. Single bouts of exercise induce a short-term energy deficit without stimulating compensatory effects on appetite, whilst limited evidence suggests that exercise training may modify subjective and homeostatic mediators of appetite in directions associated with enhanced meal-induced satiety. However, a large variability in responses exists between individuals. This article reviews the evidence relating to how adiposity, sex, and habitual physical activity modulate exercise-induced appetite, energy intake, and appetite-related hormone responses. The balance of evidence suggests that adiposity and sex do not modify appetite or energy intake responses to acute or chronic exercise interventions, but individuals with higher habitual physical activity levels may better adjust energy intake in response to energy balance perturbations. The effect of these individual characteristics and behaviours on appetite-related hormone responses to exercise remains equivocal. These findings support the continued promotion of exercise as a strategy for inducing short-term energy deficits irrespective of adiposity and sex, as well as the ability of exercise to positively influence energy balance over the longer term. Future well-controlled studies are required to further ascertain the potential mediators of appetite responses to exercise.
Topics: Adiposity; Appetite; Appetite Regulation; Energy Intake; Energy Metabolism; Exercise; Female; Ghrelin; Homeostasis; Humans; Male; Meals; Satiation
PubMed: 30131457
DOI: 10.3390/nu10091140 -
Frontiers in Cellular and Infection... 2021It is known that the microbiome affects human physiology, emotion, disease, growth, and development. Most humans exhibit reduced appetites under high temperature and...
It is known that the microbiome affects human physiology, emotion, disease, growth, and development. Most humans exhibit reduced appetites under high temperature and high humidity (HTHH) conditions, and HTHH environments favor fungal growth. Therefore, we hypothesized that the colonic mycobiota may affect the host's appetite under HTHH conditions. Changes in humidity are also associated with autoimmune diseases. In the current study mice were fed in an HTHH environment (32°C ± 2°C, relative humidity 95%) maintained an artificial climate box for 8 hours per day for 21 days. Food intake, the colonic fungal microbiome, the feces metabolome, and appetite regulators were monitored. Components of the interleukin 17 pathway were also examined. In the experimental groups food intake and body weight were reduced, and the colonic mycobiota and fecal metabolome were substantially altered compared to control groups maintained at 25°C ± 2°C and relative humidity 65%. The appetite-related proteins LEPT and POMC were upregulated in the hypothalamus ( < 0.05), and gene expression was downregulated ( < 0.05). The expression levels of PYY and O-linked β-N-acetylglucosamine were altered in colonic tissues ( < 0.05), and interleukin 17 expression was upregulated in the colon. There was a strong correlation between colonic fungus and sugar metabolism. some metabolites of cholesterol, tromethamine, and cadaverine were significantly increased. There was significant elevation of the characteristic fungi , and associated appetite suppression and interleukin 17 receptor signaling activation in some susceptible hosts, and disturbance of gut bacteria and fungi. The results indicate that the gut mycobiota plays an important role in the hypothalamus endocrine system with respect to appetite regulation the gut-brain axis, and also plays an indispensable role in the stability of the gut microbiome and immunity. The mechanisms involved in these associations require extensive further studies.
Topics: Animals; Appetite; Appetite Regulation; Basidiomycota; Colon; Dysbiosis; Humidity; Mice; Receptors, Interleukin-17; Temperature
PubMed: 34568080
DOI: 10.3389/fcimb.2021.657807 -
Comprehensive Physiology Sep 2016Perhaps the most salient behaviors that individuals engage in involve the avoidance of aversive experiences and the pursuit of pleasurable experiences. Engagement in... (Review)
Review
Perhaps the most salient behaviors that individuals engage in involve the avoidance of aversive experiences and the pursuit of pleasurable experiences. Engagement in these behaviors is regulated to a significant extent by an individual's hormonal milieu. For example, glucocorticoid hormones are produced by the hypothalamic-pituitary-adrenocortical (HPA) axis, and influence most aspects of behavior. In turn, many behaviors can influence HPA axis activity. These bidirectional interactions not only coordinate an individual's physiological and behavioral states to each other, but can also tune them to environmental conditions thereby optimizing survival. The present review details the influence of the HPA axis on many types of behavior, including appetitively-motivated behaviors (e.g., food intake and drug use), aversively-motivated behaviors (e.g., anxiety-related and depressive-like) and cognitive behaviors (e.g., learning and memory). Conversely, the manuscript also describes how engaging in various behaviors influences HPA axis activity. Our current understanding of the neuronal and/or hormonal mechanisms that underlie these interactions is also summarized. © 2016 American Physiological Society. Compr Physiol 6:1897-1934, 2016.
Topics: Animals; Appetite; Behavior; Humans; Hypothalamo-Hypophyseal System; Learning; Pituitary-Adrenal System; Stress, Psychological
PubMed: 27783863
DOI: 10.1002/cphy.c150042 -
Expert Review of Clinical Pharmacology Mar 2011Obesity has escalated into a pandemic over the past few decades. In turn, research efforts have sought to elucidate the molecular mechanisms underlying the regulation of... (Review)
Review
Obesity has escalated into a pandemic over the past few decades. In turn, research efforts have sought to elucidate the molecular mechanisms underlying the regulation of energy balance. A host of endogenous mediators regulate appetite and metabolism, and thereby control both short- and long-term energy balance. These mediators, which include gut, pancreatic and adipose neuropeptides, have been targeted in the development of anti-obesity pharmacotherapy, with the goal of amplifying anorexigenic and lipolytic signaling or blocking orexigenic and lipogenic signaling. This article presents the efficacy and safety of these anti-obesity drugs.
Topics: Animals; Anti-Obesity Agents; Appetite; Appetite Regulation; Eating; Humans; Obesity; Treatment Outcome
PubMed: 21666781
DOI: 10.1586/ecp.11.3 -
Pharmacology, Biochemistry, and Behavior Feb 2017This review examines the merits of 'food addiction' as an explanation of excessive eating (i.e., eating in excess of what is required to maintain a healthy body weight).... (Review)
Review
This review examines the merits of 'food addiction' as an explanation of excessive eating (i.e., eating in excess of what is required to maintain a healthy body weight). It describes various apparent similarities in appetites for foods and drugs. For example, conditioned environmental cues can arouse food and drug-seeking behaviour, 'craving' is an experience reported to precede eating and drug taking, 'bingeing' is associated with both eating and drug use, and conditioned and unconditioned tolerance occurs to food and drug ingestion. This is to be expected, as addictive drugs tap into the same processes and systems that evolved to motivate and control adaptive behaviours, including eating. The evidence, however, shows that drugs of abuse have more potent effects than foods, particularly in respect of their neuroadaptive effects that make them 'wanted.' While binge eating has been conceptualised as form of addictive behaviour, it is not a major cause of excessive eating, because binge eating has a far lower prevalence than obesity. Rather, it is proposed that obesity results from recurrent overconsumption of energy dense foods. Such foods are, relatedly, both attractive and (calorie for calorie) weakly satiating. Limiting their availability could partially decrease excessive eating and consequently decrease obesity. Arguably, persuading policy makers that these foods are addictive could support such action. However, blaming excessive eating on food addiction could be counterproductive, because it risks trivialising serious addictions, and because the attribution of excessive eating to food addiction implies an inability to control one's eating. Therefore, attributing everyday excessive eating to food addiction may neither explain nor significantly help reduce this problem.
Topics: Appetite; Bulimia; Craving; Drug Tolerance; Drug-Seeking Behavior; Humans; Motivation; Obesity; Reward; Substance Withdrawal Syndrome; Substance-Related Disorders
PubMed: 28063947
DOI: 10.1016/j.pbb.2017.01.001 -
International Journal of Molecular... Jun 2021Neuropeptide B (NPB) is a peptide hormone that was initially described in 2002. In humans, the biological effects of NPB depend on the activation of two G... (Review)
Review
Neuropeptide B (NPB) is a peptide hormone that was initially described in 2002. In humans, the biological effects of NPB depend on the activation of two G protein-coupled receptors, NPBWR1 (GPR7) and NPBWR2 (GPR8), and, in rodents, NPBWR1. NPB and its receptors are expressed in the central nervous system (CNS) and in peripheral tissues. NPB is also present in the circulation. In the CNS, NPB modulates appetite, reproduction, pain, anxiety, and emotions. In the peripheral tissues, NPB controls secretion of adrenal hormones, pancreatic beta cells, and various functions of adipose tissue. Experimental downregulation of either NPB or NPBWR1 leads to adiposity. Here, we review the literature with regard to NPB-dependent control of metabolism and energy homeostasis.
Topics: Animals; Appetite; Brain; Energy Metabolism; Glucose; Homeostasis; Humans; Lipid Metabolism; Neuropeptides; Reproduction
PubMed: 34205710
DOI: 10.3390/ijms22126632 -
Philosophical Transactions of the Royal... Jul 2006Interest in the biology of white adipose tissue has risen markedly with the recent surge in obesity and its associated disorders. The tissue is no longer viewed simply... (Review)
Review
Interest in the biology of white adipose tissue has risen markedly with the recent surge in obesity and its associated disorders. The tissue is no longer viewed simply as a vehicle for lipid storage; instead, it is recognized as a major endocrine and secretory organ. White adipocytes release a multiplicity of protein hormones, signals and factors, termed adipokines, with an extensive range of physiological actions. Foremost among these various adipokines is the cytokine-like hormone, leptin, which is synthesized predominantly in white fat. Leptin plays a critical role in the control of appetite and energy balance, with mutations in the genes encoding the hormone or its receptor leading to profound obesity in both rodents and man. Leptin regulates appetite primarily through an interaction with hypothalamic neuroendocrine pathways, inhibiting orexigenic peptides such as neuropeptide Y and orexin A, and stimulating anorexigenic peptides such as proopiomelanocortin. White fat also secretes several putative appetite-related adipokines, which include interleukin-6 and adiponectin, but whether these are indeed significant signals in the regulation of food intake has not been established. Through leptin and the other adipokines it is evident that adipose tissue communicates extensively with other organs and plays a pervasive role in metabolic homeostasis.
Topics: Adipocytes; Adipose Tissue; Appetite; Energy Metabolism; Humans
PubMed: 16815801
DOI: 10.1098/rstb.2006.1859 -
PloS One 2016Exposure to food odours increases the appetite for congruent foods and decreases the appetite for incongruent foods. However, the effect of exposure to a variety of food...
BACKGROUND
Exposure to food odours increases the appetite for congruent foods and decreases the appetite for incongruent foods. However, the effect of exposure to a variety of food odours, as often occurs in daily life, is unknown.
OBJECTIVE
Investigate how switching between sweet and savoury odours affects the appetite for sweet and savoury products.
DESIGN
Thirty women (age: 18-45y; BMI: 18.5-25kg/m2) intensely smelled the contents of cups filled with banana, meat or water (no-odour) in a within-subject design with four combinations: no-odour/banana, no-odour/meat, meat/banana and banana/meat. Participants received one combination per test day. In each combination, two cups with different fillings were smelled for five minutes after each other. Treatment order was balanced as much as possible. The effects of previous exposure and current odour on the appetite for (in)congruent sweet and savoury products, and odour pleasantness were analysed. A change from meat to banana odour or banana to meat odour was referred to as switch, whereas a change from no-odour to meat odour or no-odour to banana odour was no-switch.
RESULTS
The current odour (P<0.001), as opposed to the previous exposure (P = 0.71), determined the appetite for (in)congruent sweet and savoury products, already one minute after a switch between sweet and savoury odours. The pleasantness of the odour decreased during odour exposure (P = 0.005).
CONCLUSIONS
After a switch, the appetite for specific products quickly adjusted to the new odour and followed the typical pattern as found during odour exposure in previous studies. Interestingly, the appetite for the smelled food remained elevated during odour exposure, known as sensory-specific appetite, whereas the pleasantness of the odour decreased over time, previously termed olfactory sensory-specific satiety. This seeming contradiction may result from different mechanisms underlying the odour-induced anticipation of food intake versus the decrease in hedonic value during prolonged sensory stimulation.
Topics: Adolescent; Adult; Appetite; Female; Food Preferences; Humans; Meat; Middle Aged; Musa; Odorants; Surveys and Questionnaires; Taste; Time Factors; Young Adult
PubMed: 26751975
DOI: 10.1371/journal.pone.0146652 -
Annals of the New York Academy of... Jan 2018The central nervous system (CNS) plays a vital role in regulating energy balance and metabolism. Over the last 50 years, studies in animal models have allowed us to... (Review)
Review
The central nervous system (CNS) plays a vital role in regulating energy balance and metabolism. Over the last 50 years, studies in animal models have allowed us to identify critical CNS regions involved in these processes and even crucial cell populations. Now, techniques for genetically and anatomically targeted manipulation of specific neural populations using light (optogenetic), ligands (chemogenetic), or magnetic fields (radiogenetic/magnetogenetic) allow detailed investigation of circuits involved in metabolic regulation. In this review, we provide a brief overview of recent studies using light- and magnetic field-regulated neural activity to investigate the neural circuits contributing to metabolic control.
Topics: Animals; Appetite; Central Nervous System; Electromagnetic Fields; Energy Metabolism; Equipment Design; Feeding Behavior; Gene Expression Regulation; Glucose; Homeostasis; Humans; Hypothalamus; Ion Channels; Lasers; Magnetite Nanoparticles; Neurons; Optogenetics; Protein Engineering; Receptors, G-Protein-Coupled
PubMed: 29106710
DOI: 10.1111/nyas.13468