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Frontiers in Endocrinology 2021Appetite is the basis for obtaining food and maintaining normal metabolism. Toll-like receptor 4 (TLR4) is an important receptor expressed in the brain that induces... (Review)
Review
Appetite is the basis for obtaining food and maintaining normal metabolism. Toll-like receptor 4 (TLR4) is an important receptor expressed in the brain that induces inflammatory signaling after activation. Inflammation is considered to affect the homeostatic and non-homeostatic systems of appetite, which are dominated by hypothalamic and mesolimbic dopamine signaling. Although the pathological features of many types of inflammation are known, their physiological functions in appetite are largely unknown. This review mainly addresses several key issues, including the structures of the homeostatic and non-homeostatic systems. In addition, the mechanism by which TLR4-induced inflammatory signaling contributes to these two systems to regulate appetite is also discussed. This review will provide potential opportunities to develop new therapeutic interventions that control appetite under inflammatory conditions.
Topics: Animals; Appetite Regulation; Eating; Homeostasis; Humans; Hypothalamus; Inflammation; Signal Transduction; Toll-Like Receptor 4
PubMed: 34899611
DOI: 10.3389/fendo.2021.777997 -
Journal of Neuroendocrinology Sep 2023Serotonin is a neurotransmitter that is synthesized and released from the brainstem raphe nuclei to affect many brain functions. It is well known that the activity of... (Review)
Review
Serotonin is a neurotransmitter that is synthesized and released from the brainstem raphe nuclei to affect many brain functions. It is well known that the activity of raphe serotonergic neurons is changed in response to the changes in feeding status to regulate appetite via the serotonin receptors. Likewise, changes in volume status are known to alter the activity of raphe serotonergic neurons and drugs targeting serotonin receptors were shown to affect sodium appetite. Therefore, the central serotonin system appears to regulate ingestion of both food and salt, although neural mechanisms that induce appetite in response to hunger and sodium appetite in response to volume depletion are largely distinct from each other. In this review, we discuss our current knowledge regarding the regulation of ingestion - appetite and sodium appetite - by the central serotonin system.
Topics: Appetite; Sodium; Serotonin; Raphe Nuclei; Brain Stem; Appetite Regulation
PubMed: 37525500
DOI: 10.1111/jne.13328 -
Peptides Oct 2021Appetite is closely regulated not only by gut hormonal and neuronal peptides but also by exogenous peptides derived from food proteins. Food proteins are now recognized... (Review)
Review
Appetite is closely regulated not only by gut hormonal and neuronal peptides but also by exogenous peptides derived from food proteins. Food proteins are now recognized to contain many thousands of bioactive compounds that provide additional health benefits beyond their nutritional effects. Bioactive peptides are beneficial to the life and/or to regulate physiological functions. Although animal protein products have been widely applied in the food industry, exploring the possibilities of developing functional foods based on plant protein-derived peptides is considered attractive for achieving sustainable development goals. In addition, peptides from plant proteins have the potential to treat numerous diseases or risk factors and may therefore facilitate a healthy life expectancy. In this review, we discuss the identified plant-based bioactive peptides and their appetite regulating effects. Plant-based bioactive peptides may provide new opportunities to discover novel approaches that can improve and prevent diseases in a sustainable environment.
Topics: Adiposity; Animals; Appetite Regulation; Appetite Stimulants; Eating; Humans; Peptide Fragments; Peptides; Plant Proteins; Ribulose-Bisphosphate Carboxylase
PubMed: 34265369
DOI: 10.1016/j.peptides.2021.170608 -
Neuroendocrinology 2023Understanding the complex action mechanism of appetite regulation peptides can significantly impact therapeutic options in the treatment of obesity and other metabolic... (Review)
Review
Understanding the complex action mechanism of appetite regulation peptides can significantly impact therapeutic options in the treatment of obesity and other metabolic diseases. Hypothalamic alpha-melanocyte-stimulating hormone (α-MSH) is an anorexigenic peptide, closely related to the occurrence of obesity, playing a central role in food intake and energy expenditure. In the central nervous system, α-MSH is cleaved from proopiomelanocortin and then released into different hypothalamic regions to act on melanocortin 3/4 receptor-expressing neurons, lowering food intake, and raising energy expenditure via appetite suppression and sympathetic nervous system. Furthermore, it can increase the transmission of some anorexigenic hormones (e.g., dopamine) and interact with other orexigenic factors (e.g., agouti-related protein, neuropeptide Y) to influence food reward rather than merely feeding behavior. Therefore, α-MSH is a critical node of the hypothalamus in transmitting appetite suppression signals and is a key component of the central appetite-regulating circuits. Herein, we describe the role of α-MSH in appetite suppression in terms of specific receptors, effector neurons, sites of action, and the interaction with other appetite-relative peptides, respectively. We focus on the role of α-MSH in obesity. The status of research on α-MSH-related drugs is also discussed. With the intention of illuminating a new approach for targeting α-MSH in the hypothalamus as a strategy to manage obesity, we hope to further understand the direct or indirect mechanisms by which α-MSH exerts its appetite-regulating effects.
Topics: Humans; alpha-MSH; Appetite Regulation; Appetite; Obesity; Hypothalamus
PubMed: 37094550
DOI: 10.1159/000530804 -
Archives of Disease in Childhood Feb 2006The worsening global obesity epidemic, particularly the increase in childhood obesity, has prompted research into the mechanisms of appetite regulation. Complex pathways... (Review)
Review
The worsening global obesity epidemic, particularly the increase in childhood obesity, has prompted research into the mechanisms of appetite regulation. Complex pathways modulate energy balance, involving appetite centres in the hypothalamus and brain stem, and hormonal signals of energy status released by the gut and by the periphery. Better understanding of appetite regulation improves understanding of the aetiology of obesity. Manipulation of this homoeostatic system offers potentially useful treatments for obesity.
Topics: Adult; Animals; Appetite Regulation; Child; Child, Preschool; Energy Metabolism; Gastrointestinal Hormones; Homeostasis; Hormones; Humans; Hypothalamus; Obesity; Satiation
PubMed: 16428368
DOI: 10.1136/adc.2005.073759 -
Obesity (Silver Spring, Md.) Mar 2017This paper reviews the state of the science on psychological and neural contributions to appetite self-regulation in the context of obesity. (Review)
Review
OBJECTIVE
This paper reviews the state of the science on psychological and neural contributions to appetite self-regulation in the context of obesity.
METHODS
Three content areas (neural systems and cognitive functions; parenting and early childhood development; and goal setting and goal striving) served to illustrate different perspectives on the psychological and neural factors that contribute to appetite dysregulation in the context of obesity. Talks were initially delivered at an NIH workshop consisting of experts in these three content areas, and then content areas were further developed through a review of the literature.
RESULTS
Self-regulation of appetite involves a complex interaction between multiple domains, including cognitive, neural, social, and goal-directed behaviors and decision-making. Self-regulation failures can arise from any of these factors, and the resulting implications for obesity should be considered in light of each domain. In some cases, self-regulation is amenable to intervention; however, this does not appear to be universally true, which has implications for both prevention and intervention efforts.
CONCLUSIONS
Appetite regulation is a complex, multifactorial construct. When considering its role in the obesity epidemic, it is advisable to consider its various dimensions together to best inform prevention and treatment efforts.
Topics: Appetite; Appetite Regulation; Cognition; Cognitive Dysfunction; Health Education; Humans; Neurons; Obesity
PubMed: 28229541
DOI: 10.1002/oby.21789 -
Appetite Jan 2020Human body weight (BW), or some variable related to it, is physiologically regulated. That is, negative feedback from changes in BW elicits compensatory influences on... (Review)
Review
Human body weight (BW), or some variable related to it, is physiologically regulated. That is, negative feedback from changes in BW elicits compensatory influences on appetite, which may be called BW-regulatory appetite, and a component of energy expenditure (EE) called adaptive thermogenesis (AdEE). BW-regulatory appetite is of general significance because it appears to be related to a variety of aspects of human appetite beyond just energy intake. BW regulation, BW-regulatory appetite and AdEE are frequently discussed using concepts derived from control theory, which is the mathematical description of dynamic systems involving negative feedback. The aim of this review is to critically assess these discussions. Two general types of negative-feedback control have been invoked to describe BW regulation, set-point control and simple negative-feedback control, often called settling-point control in the BW literature. The distinguishing feature of set-point systems is the existence of an externally controlled target level of regulation, the set point. The performance of almost any negative-feedback regulatory system, however, can be modeled on the basis of feedback gain without including a set point. In both set-point and simple negative-feedback models of BW regulation, the precision of regulation is usually determined mainly by feedback gain, which refers to the transformations of feedback into compensatory changes in BW-regulatory appetite and AdEE. Stable BW most probably represents equilibria shaped by feedback gain and tonic open-loop challenges, especially obesogenic environments. Data indicate that simple negative-feedback control accurately models human BW regulation and that the set-point concept is superfluous unless its neuroendocrine representation is found in the brain. Additional research aimed at testing control-theory models in humans and non-human animals is warranted.
Topics: Animals; Appetite Regulation; Body Weight; Body Weight Maintenance; Energy Metabolism; Feedback, Physiological; Humans; Models, Biological; Thermogenesis
PubMed: 31494154
DOI: 10.1016/j.appet.2019.104440 -
Nutrients Aug 2023Orexin plays a significant role in the modulation of REM sleep, as well as in the regulation of appetite and feeding. This review explores, first, the current evidence... (Review)
Review
Orexin plays a significant role in the modulation of REM sleep, as well as in the regulation of appetite and feeding. This review explores, first, the current evidence on the role of orexin in the modulation of sleep and wakefulness and highlights that orexin should be considered essentially as a neurotransmitter inhibiting REM sleep and, to a much lesser extent, a wake promoting agent. Subsequently, the relationship between orexin, REM sleep, and appetite regulation is examined in detail, shedding light on their interconnected nature in both physiological conditions and diseases (such as narcolepsy, sleep-related eating disorder, idiopathic hypersomnia, and night eating syndrome). Understanding the intricate relationship between orexin, REM sleep, and appetite regulation is vital for unraveling the complex mechanisms underlying sleep-wake patterns and metabolic control. Further research in this field is encouraged in order to pave the way for novel therapeutic approaches to sleep disorders and metabolic conditions associated with orexin dysregulation.
Topics: Appetite; Sleep, REM; Orexins; Appetite Regulation; Sleep
PubMed: 37686711
DOI: 10.3390/nu15173679 -
The Journal of Physiology Mar 2022
Topics: Appetite; Appetite Regulation; Diet; Energy Intake
PubMed: 35288934
DOI: 10.1113/JP282727 -
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