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Boccia L, Borner T, Ghidewon MY, Kulka P, Piffaretti C, Doebley SA, De Jonghe BC, Grill HJ, Lutz TA, Le Foll C. Hypophagia induced by salmon calcitonin, but not by amylin, is partially driven by malaise and is mediated by CGRP neurons. Mol Metab 2022; 58:101444. [PMID: 35091058 PMCID: PMC8873943 DOI: 10.1016/j.molmet.2022.101444] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/08/2021] [Revised: 01/07/2022] [Accepted: 01/19/2022] [Indexed: 11/29/2022] Open
Abstract
Objective The behavioral mechanisms and the neuronal pathways mediated by amylin and its long-acting analog sCT (salmon calcitonin) are not fully understood and it is unclear to what extent sCT and amylin engage overlapping or distinct neuronal subpopulations to reduce food intake. We here hypothesize that amylin and sCT recruit different neuronal population to mediate their anorectic effects. Methods Viral approaches were used to inhibit calcitonin gene-related peptide (CGRP) lateral parabrachial nucleus (LPBN) neurons and assess their role in amylin’s and sCT’s ability to decrease food intake in mice. In addition, to test the involvement of LPBN CGRP neuropeptidergic signaling in the mediation of amylin and sCT’s effects, a LPBN site-specific knockdown was performed in rats. To deeper investigate whether the greater anorectic effect of sCT compared to amylin is due do the recruitment of additional neuronal pathways related to malaise multiple and distinct animal models tested whether amylin and sCT induce conditioned avoidance, nausea, emesis, and conditioned affective taste aversion. Results Our results indicate that permanent or transient inhibition of CGRP neurons in LPBN blunts sCT-, but not amylin-induced anorexia and neuronal activation. Importantly, sCT but not amylin induces behaviors indicative of malaise including conditioned affective aversion, nausea, emesis, and conditioned avoidance; the latter mediated by CGRPLPBN neurons. Conclusions Together, the present study highlights that although amylin and sCT comparably decrease food intake, sCT is distinctive from amylin in the activation of anorectic neuronal pathways associated with malaise. CGRP neurons mediate the effect of the amylin agonist salmon calcitonin (sCT) on food intake. Amylin's hypophagic effect does not require CGRP neurons. sCT-induced anorexia but not amylin is associated with malaise.
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Affiliation(s)
- Lavinia Boccia
- Institute of Veterinary Physiology, Vetsuisse Faculty, University of Zurich (UZH), 8057, Zurich, Switzerland
| | - Tito Borner
- Department of Biobehavioral Health Sciences, University of Pennsylvania, School of Nursing, Philadelphia, PA 19104, United States; Department of Psychiatry, University of Pennsylvania, Perelman School of Medicine, Philadelphia, PA 19104, United States
| | - Misgana Y Ghidewon
- Institute of Diabetes, Obesity and Metabolism and School of Arts and Sciences, University of Pennsylvania, Philadelphia, PA 19104, United States
| | - Patricia Kulka
- Institute of Veterinary Physiology, Vetsuisse Faculty, University of Zurich (UZH), 8057, Zurich, Switzerland
| | - Chiara Piffaretti
- Institute of Veterinary Physiology, Vetsuisse Faculty, University of Zurich (UZH), 8057, Zurich, Switzerland
| | - Sarah A Doebley
- Department of Biobehavioral Health Sciences, University of Pennsylvania, School of Nursing, Philadelphia, PA 19104, United States
| | - Bart C De Jonghe
- Department of Biobehavioral Health Sciences, University of Pennsylvania, School of Nursing, Philadelphia, PA 19104, United States; Department of Psychiatry, University of Pennsylvania, Perelman School of Medicine, Philadelphia, PA 19104, United States
| | - Harvey J Grill
- Institute of Diabetes, Obesity and Metabolism and School of Arts and Sciences, University of Pennsylvania, Philadelphia, PA 19104, United States
| | - Thomas A Lutz
- Institute of Veterinary Physiology, Vetsuisse Faculty, University of Zurich (UZH), 8057, Zurich, Switzerland
| | - Christelle Le Foll
- Institute of Veterinary Physiology, Vetsuisse Faculty, University of Zurich (UZH), 8057, Zurich, Switzerland.
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Stein LM, McGrath LE, Lhamo R, Koch-Laskowski K, Fortin SM, Skarbaliene J, Baader-Pagler T, Just R, Hayes MR, Mietlicki-Baase EG. The long-acting amylin/calcitonin receptor agonist ZP5461 suppresses food intake and body weight in male rats. Am J Physiol Regul Integr Comp Physiol 2021; 321:R250-R259. [PMID: 34259025 PMCID: PMC8409915 DOI: 10.1152/ajpregu.00337.2020] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2020] [Revised: 06/30/2021] [Accepted: 07/04/2021] [Indexed: 01/18/2023]
Abstract
The peptide hormone amylin reduces food intake and body weight and is an attractive candidate target for novel pharmacotherapies to treat obesity. However, the short half-life of native amylin and amylin analogs like pramlintide limits these compounds' potential utility in promoting sustained negative energy balance. Here, we evaluate the ability of the novel long-acting amylin/calcitonin receptor agonist ZP5461 to reduce feeding and body weight in rats, and also test the role of calcitonin receptors (CTRs) in the dorsal vagal complex (DVC) of the hindbrain in the energy balance effects of chronic ZP5461 administration. Acute dose-response studies indicate that systemic ZP5461 (0.5-3 nmol/kg) robustly suppresses energy intake and body weight gain in chow- and high-fat diet (HFD)-fed rats. When HFD-fed rats received chronic systemic administration of ZP5461 (1-2 nmol/kg), the compound initially produced reductions in energy intake and weight gain but failed to produce sustained suppression of intake and body weight. Using virally mediated knockdown of DVC CTRs, the ability of chronic systemic ZP5461 to promote early reductions in intake and body weight gain was determined to be mediated in part by activation of DVC CTRs, implicating the DVC as a central site of action for ZP5461. Future studies should address other dosing regimens of ZP5461 to determine whether an alternative dose/frequency of administration would produce more sustained body weight suppression.
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Affiliation(s)
- Lauren M Stein
- Department of Psychiatry, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Lauren E McGrath
- Department of Psychiatry, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Rinzin Lhamo
- Department of Psychiatry, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Kieran Koch-Laskowski
- Department of Psychiatry, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Samantha M Fortin
- Department of Psychiatry, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
| | | | | | | | - Matthew R Hayes
- Department of Psychiatry, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Elizabeth G Mietlicki-Baase
- Department of Psychiatry, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
- Department of Exercise and Nutrition Sciences, School of Public Health and Health Professions, University at Buffalo, State University of New York, Buffalo, New York
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Holt MK. Mind affects matter: Hindbrain GLP1 neurons link stress, physiology and behaviour. Exp Physiol 2021; 106:1853-1862. [PMID: 34302307 DOI: 10.1113/ep089445] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2021] [Accepted: 07/19/2021] [Indexed: 12/12/2022]
Abstract
NEW FINDINGS What is the topic of this review? This Lecture covers the role of caudal brainstem GLP1 neurons in acute and chronic stress responses. What advances does it highlight? This Lecture focuses on the recent advances in our understanding of GLP1 neurons and their physiological role in many aspects of stress. Particular focus is given to the recent elucidation, in part, of the anatomical basis for recruitment of GLP1 neurons in response to acute stress. Finally, the potential, but at this time somewhat speculative, role of GLP1 neurons in chronic stress is discussed. ABSTRACT The brain responds rapidly to stressful stimuli by increasing sympathetic outflow, activating the hypothalamic-pituitary-adrenal axis and eliciting avoidance behaviours to limit risks to safety. Stress responses are adaptive and essential but can become maladaptive when the stress is chronic, causing autonomic imbalance, hypothalamic-pituitary-adrenal axis hyper-reactivity and a state of hypervigilance. Ultimately, this contributes to the development of cardiovascular disease and affective disorders, including major depression and anxiety. Stress responses are often thought to be driven mainly by forebrain areas; however, the brainstem nucleus of the solitary tract (NTS) is ideally located to control both autonomic outflow and behaviour in response to stress. Here, I review the preclinical evidence that the NTS and its resident glucagon-like peptide-1 (GLP1)-expressing neurons are prominent mediators of stress responses. This Lecture introduces the reader to the idea of good and bad stress and outlines the types of stress that engage the NTS and GLP1 neurons. I describe in particular detail the recent studies by myself and others aimed at mapping sources of synaptic inputs to GLP1 neurons and consider the implications for our understanding of the role of GLP1 neurons in stress. This is followed by a discussion of the contribution of brain GLP1 and GLP1 neurons to behavioural and physiological stress responses. The evidence reviewed highlights a potentially prominent role for GLP1 neurons in the response of the brain to acute stress and reveals important unanswered questions regarding their role in chronic stress.
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Affiliation(s)
- Marie K Holt
- Centre for Cardiovascular and Metabolic Neuroscience, Department of Neuroscience, Physiology and Pharmacology, University College London, London, UK
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Diz-Chaves Y, Herrera-Pérez S, González-Matías LC, Lamas JA, Mallo F. Glucagon-Like Peptide-1 (GLP-1) in the Integration of Neural and Endocrine Responses to Stress. Nutrients 2020; 12:nu12113304. [PMID: 33126672 PMCID: PMC7692797 DOI: 10.3390/nu12113304] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2020] [Revised: 10/14/2020] [Accepted: 10/27/2020] [Indexed: 12/20/2022] Open
Abstract
Glucagon like-peptide 1 (GLP-1) within the brain is produced by a population of preproglucagon neurons located in the caudal nucleus of the solitary tract. These neurons project to the hypothalamus and another forebrain, hindbrain, and mesolimbic brain areas control the autonomic function, feeding, and the motivation to feed or regulate the stress response and the hypothalamic-pituitary-adrenal axis. GLP-1 receptor (GLP-1R) controls both food intake and feeding behavior (hunger-driven feeding, the hedonic value of food, and food motivation). The activation of GLP-1 receptors involves second messenger pathways and ionic events in the autonomic nervous system, which are very relevant to explain the essential central actions of GLP-1 as neuromodulator coordinating food intake in response to a physiological and stress-related stimulus to maintain homeostasis. Alterations in GLP-1 signaling associated with obesity or chronic stress induce the dysregulation of eating behavior. This review summarized the experimental shreds of evidence from studies using GLP-1R agonists to describe the neural and endocrine integration of stress responses and feeding behavior.
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Affiliation(s)
- Yolanda Diz-Chaves
- CINBIO, Universidade de Vigo, Grupo FB3A, Laboratorio de Endocrinología, 36310 Vigo, Spain;
- Correspondence: (Y.D.-C.); (F.M.); Tel.: +34-(986)-130226 (Y.D.-C.); +34-(986)-812393 (F.M.)
| | - Salvador Herrera-Pérez
- CINBIO, Universidade de Vigo, Grupo FB3B, Laboratorio de Neurociencia, 36310 Vigo, Spain; (S.H.-P.); (J.A.L.)
| | | | - José Antonio Lamas
- CINBIO, Universidade de Vigo, Grupo FB3B, Laboratorio de Neurociencia, 36310 Vigo, Spain; (S.H.-P.); (J.A.L.)
| | - Federico Mallo
- CINBIO, Universidade de Vigo, Grupo FB3A, Laboratorio de Endocrinología, 36310 Vigo, Spain;
- Correspondence: (Y.D.-C.); (F.M.); Tel.: +34-(986)-130226 (Y.D.-C.); +34-(986)-812393 (F.M.)
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Boccia L, Le Foll C, Lutz TA. Noradrenaline signaling in the LPBN mediates amylin's and salmon calcitonin's hypophagic effect in male rats. FASEB J 2020; 34:15448-15461. [PMID: 32985027 DOI: 10.1096/fj.202001456rrr] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2020] [Revised: 09/07/2020] [Accepted: 09/10/2020] [Indexed: 11/11/2022]
Abstract
The LPBN (lateral parabrachial nucleus) plays an important role in feeding control. CGRP (calcitonin gene-related peptide) LPBN neurons activation mediates the anorectic effects of different gut-derived peptides, including amylin. Amylin and its long acting analog sCT (salmon calcitonin) exert their anorectic actions primarily by directly activating neurons located in the area postrema (AP). A large proportion of projections from the AP and the adjacent nucleus of the solitary tractNTS to the LPBN, are noradrenergic (NA), and amylin-activated NAAP neurons are critical in mediating amylin's hypophagic effects. Here, we determine the functional role of NAAP amylin activated neurons to activate CGRP and non-CGRP LPBN neurons. To this end, NA was specifically depleted in the rat LPBN through a stereotaxic microinfusion of 6-OHDA, a neurotoxic agent that destroys NA terminals. While amylin (50 μg/kg) and sCT (5 μg/kg) reduced eating in sham-lesioned rats, no reduction in feeding occurred in NA-depleted animals. Further, the amylin-induced c-Fos response in the LPBN and c-Fos/CGRP colocalization were reduced in NA-depleted animals compared to controls. We conclude that AP → LPBN NA signaling, through the activation of LPBN CGRP neurons, mediates part of amylin's hypophagic effect.
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Affiliation(s)
- Lavinia Boccia
- Institute of Veterinary Physiology, University of Zurich, Zurich, Switzerland
| | - Christelle Le Foll
- Institute of Veterinary Physiology, University of Zurich, Zurich, Switzerland
| | - Thomas A Lutz
- Institute of Veterinary Physiology, University of Zurich, Zurich, Switzerland
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Foll CL, Lutz TA. Systemic and Central Amylin, Amylin Receptor Signaling, and Their Physiological and Pathophysiological Roles in Metabolism. Compr Physiol 2020; 10:811-837. [PMID: 32941692 DOI: 10.1002/cphy.c190034] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
This article in the Neural and Endocrine Section of Comprehensive Physiology discusses the physiology and pathophysiology of the pancreatic hormone amylin. Shortly after its discovery in 1986, amylin has been shown to reduce food intake as a satiation signal to limit meal size. Amylin also affects food reward, sensitizes the brain to the catabolic actions of leptin, and may also play a prominent role in the development of certain brain areas that are involved in metabolic control. Amylin may act at different sites in the brain in addition to the area postrema (AP) in the caudal hindbrain. In particular, the sensitizing effect of amylin on leptin action may depend on a direct interaction in the hypothalamus. The concept of central pathways mediating amylin action became more complex after the discovery that amylin is also synthesized in certain hypothalamic areas but the interaction between central and peripheral amylin signaling remains currently unexplored. Amylin may also play a dominant pathophysiological role that is associated with the aggregation of monomeric amylin into larger, cytotoxic molecular entities. This aggregation in certain species may contribute to the development of type 2 diabetes mellitus but also cardiovascular disease. Amylin receptor pharmacology is complex because several distinct amylin receptor subtypes have been described, because other neuropeptides [e.g., calcitonin gene-related peptide (CGRP)] can also bind to amylin receptors, and because some components of the functional amylin receptor are also used for other G-protein coupled receptor (GPCR) systems. © 2020 American Physiological Society. Compr Physiol 10:811-837, 2020.
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Affiliation(s)
- Christelle Le Foll
- Institute of Veterinary Physiology, University of Zurich, Zurich, Switzerland
| | - Thomas A Lutz
- Institute of Veterinary Physiology, University of Zurich, Zurich, Switzerland
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7
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Maske CB, Coiduras II, Ondriezek ZE, Terrill SJ, Williams DL. Intermittent High-Fat Diet Intake Reduces Sensitivity to Intragastric Nutrient Infusion and Exogenous Amylin in Female Rats. Obesity (Silver Spring) 2020; 28:942-952. [PMID: 32237211 PMCID: PMC7180114 DOI: 10.1002/oby.22779] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/17/2019] [Revised: 02/11/2020] [Accepted: 02/13/2020] [Indexed: 01/01/2023]
Abstract
OBJECTIVE Intermittent (INT) access to a high-fat diet (HFD) can induce excessive-intake phenotypes in rodents. This study hypothesized that impaired satiation responses contribute to elevated intake in an INT-HFD access model. METHODS First, this study characterized the intake and meal patterns of female rats that were subjected to an INT HFD in which a 45% HFD was presented for 20 hours every fourth day. To examine nutrient-induced satiation, rats received intragastric infusions of saline or Ensure Plus prior to darkness-onset food access. A similar design was used to examine sensitivity to the satiating effect of amylin. This study then examined whether an INT HFD influences amylin-induced c-Fos in feeding-relevant brain areas. RESULTS Upon INT HFD access, rats consumed meals of larger size. The anorexic response to intragastric Ensure infusion and exogenous amylin treatment was blunted in INT rats on both chow-only and INT-HFD days of the diet regimen, compared with chow-maintained and continuous-HFD rats. An INT HFD did not influence amylin-induced c-Fos in the area postrema, nucleus of the solitary tract, and lateral parabrachial nucleus. CONCLUSIONS Impaired satiation responses, mediated in part by reduced sensitivity to amylin, may explain the elevated intake observed upon INT HFD access and may play a role in disorders of INT overconsumption, including binge eating.
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Affiliation(s)
- Calyn B Maske
- Program in Neuroscience, Department of Psychology, Florida State University, Tallahassee, Florida, USA
| | - Isabel I Coiduras
- Program in Neuroscience, Department of Psychology, Florida State University, Tallahassee, Florida, USA
| | - Zeleen E Ondriezek
- Program in Neuroscience, Department of Psychology, Florida State University, Tallahassee, Florida, USA
| | - Sarah J Terrill
- Program in Neuroscience, Department of Psychology, Florida State University, Tallahassee, Florida, USA
| | - Diana L Williams
- Program in Neuroscience, Department of Psychology, Florida State University, Tallahassee, Florida, USA
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Müller TD, Finan B, Bloom SR, D'Alessio D, Drucker DJ, Flatt PR, Fritsche A, Gribble F, Grill HJ, Habener JF, Holst JJ, Langhans W, Meier JJ, Nauck MA, Perez-Tilve D, Pocai A, Reimann F, Sandoval DA, Schwartz TW, Seeley RJ, Stemmer K, Tang-Christensen M, Woods SC, DiMarchi RD, Tschöp MH. Glucagon-like peptide 1 (GLP-1). Mol Metab 2019; 30:72-130. [PMID: 31767182 PMCID: PMC6812410 DOI: 10.1016/j.molmet.2019.09.010] [Citation(s) in RCA: 875] [Impact Index Per Article: 175.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/17/2019] [Revised: 09/10/2019] [Accepted: 09/22/2019] [Indexed: 02/06/2023] Open
Abstract
BACKGROUND The glucagon-like peptide-1 (GLP-1) is a multifaceted hormone with broad pharmacological potential. Among the numerous metabolic effects of GLP-1 are the glucose-dependent stimulation of insulin secretion, decrease of gastric emptying, inhibition of food intake, increase of natriuresis and diuresis, and modulation of rodent β-cell proliferation. GLP-1 also has cardio- and neuroprotective effects, decreases inflammation and apoptosis, and has implications for learning and memory, reward behavior, and palatability. Biochemically modified for enhanced potency and sustained action, GLP-1 receptor agonists are successfully in clinical use for the treatment of type-2 diabetes, and several GLP-1-based pharmacotherapies are in clinical evaluation for the treatment of obesity. SCOPE OF REVIEW In this review, we provide a detailed overview on the multifaceted nature of GLP-1 and its pharmacology and discuss its therapeutic implications on various diseases. MAJOR CONCLUSIONS Since its discovery, GLP-1 has emerged as a pleiotropic hormone with a myriad of metabolic functions that go well beyond its classical identification as an incretin hormone. The numerous beneficial effects of GLP-1 render this hormone an interesting candidate for the development of pharmacotherapies to treat obesity, diabetes, and neurodegenerative disorders.
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Affiliation(s)
- T D Müller
- Institute for Diabetes and Obesity, Helmholtz Diabetes Center, Helmholtz Zentrum München, German Research Center for Environmental Health (GmbH), Neuherberg, Germany; German Center for Diabetes Research (DZD), Neuherberg, Germany; Department of Pharmacology and Experimental Therapy, Institute of Experimental and Clinical Pharmacology and Toxicology, Eberhard Karls University Hospitals and Clinics, Tübingen, Germany.
| | - B Finan
- Novo Nordisk Research Center Indianapolis, Indianapolis, IN, USA
| | - S R Bloom
- Division of Diabetes, Endocrinology and Metabolism, Imperial College London, London, UK
| | - D D'Alessio
- Division of Endocrinology, Duke University Medical Center, Durham, NC, USA
| | - D J Drucker
- The Department of Medicine, Lunenfeld-Tanenbaum Research Institute, Mt. Sinai Hospital, University of Toronto, Ontario, M5G1X5, Canada
| | - P R Flatt
- SAAD Centre for Pharmacy & Diabetes, Ulster University, Coleraine, Northern Ireland, UK
| | - A Fritsche
- German Center for Diabetes Research (DZD), Neuherberg, Germany; Institute for Diabetes Research and Metabolic Diseases of the Helmholtz Center Munich at the University of Tübingen, Tübingen, Germany; Division of Endocrinology, Diabetology, Vascular Disease, Nephrology and Clinical Chemistry, Department of Internal Medicine, University of Tübingen, Tübingen, Germany
| | - F Gribble
- Metabolic Research Laboratories and Medical Research Council Metabolic Diseases Unit, Wellcome Trust-Medical Research Council, Institute of Metabolic Science, Addenbrooke's Hospital, University of Cambridge, Cambridge, CB2 0QQ, UK
| | - H J Grill
- Institute of Diabetes, Obesity and Metabolism, Department of Psychology, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - J F Habener
- Laboratory of Molecular Endocrinology, Massachusetts General Hospital, Harvard University, Boston, MA, USA
| | - J J Holst
- Novo Nordisk Foundation Center for Basic Metabolic Research, Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - W Langhans
- Physiology and Behavior Laboratory, ETH Zurich, Schwerzenbach, Switzerland
| | - J J Meier
- Diabetes Division, St Josef Hospital, Ruhr-University Bochum, Bochum, Germany
| | - M A Nauck
- Diabetes Center Bochum-Hattingen, St Josef Hospital (Ruhr-Universität Bochum), Bochum, Germany
| | - D Perez-Tilve
- Department of Internal Medicine, University of Cincinnati-College of Medicine, Cincinnati, OH, USA
| | - A Pocai
- Cardiovascular & ImmunoMetabolism, Janssen Research & Development, Welsh and McKean Roads, Spring House, PA, 19477, USA
| | - F Reimann
- Metabolic Research Laboratories and Medical Research Council Metabolic Diseases Unit, Wellcome Trust-Medical Research Council, Institute of Metabolic Science, Addenbrooke's Hospital, University of Cambridge, Cambridge, CB2 0QQ, UK
| | - D A Sandoval
- Department of Surgery, University of Michigan Medical School, Ann Arbor, MI, USA
| | - T W Schwartz
- Novo Nordisk Foundation Center for Basic Metabolic Research, University of Copenhagen, DL-2200, Copenhagen, Denmark; Department of Biomedical Sciences, University of Copenhagen, DK-2200, Copenhagen, Denmark
| | - R J Seeley
- Department of Surgery, University of Michigan Medical School, Ann Arbor, MI, USA
| | - K Stemmer
- Institute for Diabetes and Obesity, Helmholtz Diabetes Center, Helmholtz Zentrum München, German Research Center for Environmental Health (GmbH), Neuherberg, Germany; German Center for Diabetes Research (DZD), Neuherberg, Germany
| | - M Tang-Christensen
- Obesity Research, Global Drug Discovery, Novo Nordisk A/S, Måløv, Denmark
| | - S C Woods
- Department of Psychiatry and Behavioral Neuroscience, University of Cincinnati, Cincinnati, OH, USA
| | - R D DiMarchi
- Novo Nordisk Research Center Indianapolis, Indianapolis, IN, USA; Department of Chemistry, Indiana University, Bloomington, IN, USA
| | - M H Tschöp
- German Center for Diabetes Research (DZD), Neuherberg, Germany; Division of Metabolic Diseases, Department of Medicine, Technische Universität München, Munich, Germany; Helmholtz Zentrum München, German Research Center for Environmental Health (GmbH), Neuherberg, Germany
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McKinley MJ, Denton DA, Ryan PJ, Yao ST, Stefanidis A, Oldfield BJ. From sensory circumventricular organs to cerebral cortex: Neural pathways controlling thirst and hunger. J Neuroendocrinol 2019; 31:e12689. [PMID: 30672620 DOI: 10.1111/jne.12689] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/05/2018] [Revised: 01/20/2019] [Accepted: 01/21/2019] [Indexed: 01/14/2023]
Abstract
Much progress has been made during the past 30 years with respect to elucidating the neural and endocrine pathways by which bodily needs for water and energy are brought to conscious awareness through the generation of thirst and hunger. One way that circulating hormones influence thirst and hunger is by acting on neurones within sensory circumventricular organs (CVOs). This is possible because the subfornical organ and organum vasculosum of the lamina terminalis (OVLT), the sensory CVOs in the forebrain, and the area postrema in the hindbrain lack a normal blood-brain barrier such that neurones within them are exposed to blood-borne agents. The neural signals generated by hormonal action in these sensory CVOs are relayed to several sites in the cerebral cortex to stimulate or inhibit thirst or hunger. The subfornical organ and OVLT respond to circulating angiotensin II, relaxin and hypertonicity to drive thirst-related neural pathways, whereas circulating amylin, leptin and possibly glucagon-like peptide-1 act at the area postrema to influence neural pathways inhibiting food intake. As a result of investigations using functional brain imaging techniques, the insula and anterior cingulate cortex, as well as several other cortical sites, have been implicated in the conscious perception of thirst and hunger in humans. Viral tracing techniques show that the anterior cingulate cortex and insula receive neural inputs from thirst-related neurones in the subfornical organ and OVLT, with hunger-related neurones in the area postrema having polysynaptic efferent connections to these cortical regions. For thirst, initially, the median preoptic nucleus and, subsequently, the thalamic paraventricular nucleus and lateral hypothalamus have been identified as likely sites of synaptic links in pathways from the subfornical organ and OVLT to the cortex. The challenge remains to identify the links in the neural pathways that relay signals originating in sensory CVOs to cortical sites subserving either thirst or hunger.
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Affiliation(s)
- Michael J McKinley
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, Victoria, Australia
- Department of Physiology, University of Melbourne, Parkville, Victoria, Australia
| | - Derek A Denton
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, Victoria, Australia
- Office of the Dean of Medicine, University of Melbourne, Parkville, Victoria, Australia
| | - Philip J Ryan
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, Victoria, Australia
| | - Song T Yao
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, Victoria, Australia
| | - Aneta Stefanidis
- Department of Physiology, Monash University, Clayton, Victoria, Australia
| | - Brian J Oldfield
- Department of Physiology, Monash University, Clayton, Victoria, Australia
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Kjaergaard M, Salinas CBG, Rehfeld JF, Secher A, Raun K, Wulff BS. PYY(3-36) and exendin-4 reduce food intake and activate neuronal circuits in a synergistic manner in mice. Neuropeptides 2019; 73:89-95. [PMID: 30471778 DOI: 10.1016/j.npep.2018.11.004] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/08/2018] [Revised: 11/17/2018] [Accepted: 11/18/2018] [Indexed: 12/11/2022]
Abstract
Peptide YY(3-36) ((PYY(3-36)) and glucagon like peptide 1 (GLP-1) in combination reduce food intake and body weight in an additive or synergistic manner in animal models and in humans. Nevertheless, the mechanisms behind are not completely understood. The present study aims to investigate the effect of combining PYY(3-36) and the GLP-1 receptor agonist exendin-4 (Ex4) by examining acute food intake and global neuronal activation as measured by c-fos in C57BL/6 J mice. An additive reduction in food intake was found 1.5 h after s.c dosing with the combination of PYY(3-36) (200 μg/kg) and Ex4 (2.5 μg/kg). This was associated with a synergistic enhancement of c-fos reactivity in central amygdalar nucleus (CeA), rostral part of the mediobasal arcuate nucleus (ARH), supratrigeminal nucleus (SUT), lateral parabrachial nucleus (PB), area postrema (AP) and nucleus tractus solitarius (NTS) compared to vehicle, PYY(3-36) and Ex4 individually dosed mice. The regions activated by Ex4 individually and PYY(3-36) and Ex4 in combination resembled each other, but the combination group had a significantly stronger c-fos response. Twenty-five brain areas were activated by PYY(3-36) and Ex4 in combination compared to vehicle versus nine brain areas by Ex4 individually. No significant increase in c-fos reactivity was found by PYY(3-36) compared to vehicle dosed mice. The neuronal activation of ARH and the AP/NTS to PB to CeA pathway is important for appetite regulation while SUT has not previously been reported in the regulation of energy balance. As PYY(3-36) and Ex4 act on different neurons leading to recruitment of different signalling pathways within and to the brain, an interaction of these pathways may contribute to their additive/synergistic action. Thus, PYY(3-36) boosts the effect of Ex4 possibly by inducing less inhibition of neuronal activity leading to an enhanced neuronal activity induced by Ex4.
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Affiliation(s)
- Marina Kjaergaard
- Histology and Imaging, Novo Nordisk A/S, 2760 Måløv, Denmark.; Department of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, 2200 Copenhagen N, Denmark..
| | | | - Jens F Rehfeld
- Department of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, 2200 Copenhagen N, Denmark
| | - Anna Secher
- Histology and Imaging, Novo Nordisk A/S, 2760 Måløv, Denmark
| | - Kirsten Raun
- Obesity Research, Novo Nordisk A/S, 2760 Måløv, Denmark
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Almeida LS, Castro‐Lopes JM, Neto FL, Potes CS. Amylin, a peptide expressed by nociceptors, modulates chronic neuropathic pain. Eur J Pain 2019; 23:784-799. [DOI: 10.1002/ejp.1347] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2018] [Revised: 11/05/2018] [Accepted: 11/27/2018] [Indexed: 12/18/2022]
Affiliation(s)
- Lígia Sofia Almeida
- Instituto de Investigação e Inovação em Saúde, Universidade do Porto Porto Portugal
- IBMC – Instituto de Biologia Molecular e Celular, Universidade do Porto Porto Portugal
- Departamento de Biomedicina – Unidade de Biologia Experimental, Faculdade de Medicina Universidade do Porto Porto Portugal
| | - José Manuel Castro‐Lopes
- Instituto de Investigação e Inovação em Saúde, Universidade do Porto Porto Portugal
- IBMC – Instituto de Biologia Molecular e Celular, Universidade do Porto Porto Portugal
- Departamento de Biomedicina – Unidade de Biologia Experimental, Faculdade de Medicina Universidade do Porto Porto Portugal
| | - Fani Lourença Neto
- Instituto de Investigação e Inovação em Saúde, Universidade do Porto Porto Portugal
- IBMC – Instituto de Biologia Molecular e Celular, Universidade do Porto Porto Portugal
- Departamento de Biomedicina – Unidade de Biologia Experimental, Faculdade de Medicina Universidade do Porto Porto Portugal
| | - Catarina Soares Potes
- Instituto de Investigação e Inovação em Saúde, Universidade do Porto Porto Portugal
- IBMC – Instituto de Biologia Molecular e Celular, Universidade do Porto Porto Portugal
- Departamento de Biomedicina – Unidade de Biologia Experimental, Faculdade de Medicina Universidade do Porto Porto Portugal
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12
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Schier LA, Spector AC. The Functional and Neurobiological Properties of Bad Taste. Physiol Rev 2019; 99:605-663. [PMID: 30475657 PMCID: PMC6442928 DOI: 10.1152/physrev.00044.2017] [Citation(s) in RCA: 44] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2017] [Revised: 05/18/2018] [Accepted: 06/30/2018] [Indexed: 12/12/2022] Open
Abstract
The gustatory system serves as a critical line of defense against ingesting harmful substances. Technological advances have fostered the characterization of peripheral receptors and have created opportunities for more selective manipulations of the nervous system, yet the neurobiological mechanisms underlying taste-based avoidance and aversion remain poorly understood. One conceptual obstacle stems from a lack of recognition that taste signals subserve several behavioral and physiological functions which likely engage partially segregated neural circuits. Moreover, although the gustatory system evolved to respond expediently to broad classes of biologically relevant chemicals, innate repertoires are often not in register with the actual consequences of a food. The mammalian brain exhibits tremendous flexibility; responses to taste can be modified in a specific manner according to bodily needs and the learned consequences of ingestion. Therefore, experimental strategies that distinguish between the functional properties of various taste-guided behaviors and link them to specific neural circuits need to be applied. Given the close relationship between the gustatory and visceroceptive systems, a full reckoning of the neural architecture of bad taste requires an understanding of how these respective sensory signals are integrated in the brain.
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Affiliation(s)
- Lindsey A Schier
- Department of Biological Sciences, University of Southern California , Los Angeles, California ; and Department of Psychology and Program in Neuroscience, Florida State University , Tallahassee, Florida
| | - Alan C Spector
- Department of Biological Sciences, University of Southern California , Los Angeles, California ; and Department of Psychology and Program in Neuroscience, Florida State University , Tallahassee, Florida
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13
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Williams DL, Lilly NA, Edwards IJ, Yao P, Richards JE, Trapp S. GLP-1 action in the mouse bed nucleus of the stria terminalis. Neuropharmacology 2018; 131:83-95. [PMID: 29221794 PMCID: PMC5840513 DOI: 10.1016/j.neuropharm.2017.12.007] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2017] [Revised: 10/13/2017] [Accepted: 12/03/2017] [Indexed: 01/07/2023]
Abstract
Glucagon-like peptide-1 (GLP-1) injected into the brain reduces food intake. Similarly, activation of preproglucagon (PPG) cells in the hindbrain which synthesize GLP-1, reduces food intake. However, it is far from clear whether this happens because of satiety, nausea, reduced reward, or even stress. Here we explore the role of the bed nucleus of the stria terminalis (BNST), an area involved in feeding control as well as stress responses, in GLP-1 responses. Using cre-expressing mice we visualized projections of NTS PPG neurons and GLP-1R-expressing BNST cells with AAV-driven Channelrhodopsin-YFP expression. The BNST displayed many varicose YFP+ PPG axons in the ventral and less in the dorsal regions. Mice which express RFP in GLP-1R neurons had RFP+ cells throughout the BNST with the highest density in the dorsal part, suggesting that PPG neuron-derived GLP-1 acts in the BNST. Indeed, injection of GLP-1 into the BNST reduced chow intake during the dark phase, whereas injection of the GLP-1 receptor antagonist Ex9 increased feeding. BNST-specific GLP-1-induced food suppression was less effective in mice on high fat (HF, 60%) diet, and Ex9 had no effect. Restraint stress-induced hypophagia was attenuated by BNST Ex9 treatment, further supporting a role for endogenous brain GLP-1. Finally, whole-cell patch clamp recordings of RFP+ BNST neurons demonstrated that GLP-1 elicited either a depolarizing or hyperpolarizing reversible response that was of opposite polarity to that under dopamine. Our data support a physiological role for BNST GLP-1R in feeding, and suggest complex cellular responses to GLP-1 in this nucleus.
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Affiliation(s)
- Diana L Williams
- Psychology Department & Program in Neuroscience, Florida State University, USA
| | - Nicole A Lilly
- Psychology Department & Program in Neuroscience, Florida State University, USA
| | - Ian J Edwards
- Centre for Cardiovascular and Metabolic Neuroscience, Department of Neuroscience, Physiology & Pharmacology, University College London, London, WC1E 6BT, UK
| | - Pallas Yao
- Centre for Cardiovascular and Metabolic Neuroscience, Department of Neuroscience, Physiology & Pharmacology, University College London, London, WC1E 6BT, UK
| | - James E Richards
- Centre for Cardiovascular and Metabolic Neuroscience, Department of Neuroscience, Physiology & Pharmacology, University College London, London, WC1E 6BT, UK
| | - Stefan Trapp
- Centre for Cardiovascular and Metabolic Neuroscience, Department of Neuroscience, Physiology & Pharmacology, University College London, London, WC1E 6BT, UK.
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14
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Maske CB, Jackson CM, Terrill SJ, Eckel LA, Williams DL. Estradiol modulates the anorexic response to central glucagon-like peptide 1. Horm Behav 2017; 93:109-117. [PMID: 28558993 PMCID: PMC5555302 DOI: 10.1016/j.yhbeh.2017.05.012] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/12/2017] [Revised: 04/24/2017] [Accepted: 05/26/2017] [Indexed: 01/03/2023]
Abstract
Estrogens suppress feeding in part by enhancing the response to satiation signals. Glucagon-like peptide 1 (GLP-1) acts on receptor populations both peripherally and centrally to affect food intake. We hypothesized that modulation of the central GLP-1 system is one of the mechanisms underlying the effects of estrogens on feeding. We assessed the anorexic effect of 0, 1, and 10μg doses of GLP-1 administered into the lateral ventricle of bilaterally ovariectomized (OVX) female rats on a cyclic regimen of either 2μg β-estradiol-3-benzoate (EB) or oil vehicle 30min prior to dark onset on the day following hormone treatment. Central GLP-1 treatment significantly suppressed food intake in EB-treated rats at both doses compared to vehicle, whereas only the 10μg GLP-1 dose was effective in oil-treated rats. To follow up, we examined whether physiologic-dose cyclic estradiol treatment influences GLP-1-induced c-Fos in feeding-relevant brain areas of OVX females. GLP-1 significantly increased c-Fos expression in the area postrema (AP) and nucleus of the solitary tract (NTS), and the presence of estrogens may be required for this effect in the paraventricular nucleus of the hypothalamus (PVN). Together, these data suggest that modulation of the central GLP-1 system may be one of the mechanisms by which estrogens suppress food intake, and highlight the PVN as a region of interest for future investigation.
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Affiliation(s)
- Calyn B Maske
- Department of Psychology, Florida State University, Tallahassee, FL 32306, United States
| | - Christine M Jackson
- Department of Psychology, Florida State University, Tallahassee, FL 32306, United States
| | - Sarah J Terrill
- Department of Psychology, Florida State University, Tallahassee, FL 32306, United States
| | - Lisa A Eckel
- Department of Psychology, Florida State University, Tallahassee, FL 32306, United States
| | - Diana L Williams
- Department of Psychology, Florida State University, Tallahassee, FL 32306, United States.
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15
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Systemic administration of anorexic gut peptide hormones impairs hedonic-driven sucrose consumption in mice. Physiol Behav 2016; 171:158-164. [PMID: 28040488 DOI: 10.1016/j.physbeh.2016.12.034] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2016] [Revised: 12/26/2016] [Accepted: 12/26/2016] [Indexed: 01/01/2023]
Abstract
A number of reports suggest that gut hormones such as cholecystokinin (CCK), glucagon-like peptide 1 (GLP-1), and peptide YY(3-36) (PYY3-36), which are released postprandially, suppress homeostatic food intake and result in satiety and the termination of feeding. However, it remains unclear whether these peptide hormones also suppress non-homeostatic consumption of palatable foods or fluids. To examine whether gut hormones reduce hedonically motivated sugar consumption, we assessed the effects of intraperitoneal administration of these gut hormones on the consumption of a highly palatable sucrose solution, using a mouse model we previously established for binge-like sucrose overconsumption (Yasoshima and Shimura, 2015). To reduce homeostatic hunger, chow was available at nighttime prior to testing. After a limited-access training procedure for 10days, during which access to both sucrose and chow were controlled, on the test day, control mice injected with saline consumed significantly more sucrose than during the pre-training period. In contrast, sucrose consumption on the test day in the mice injected with CCK-8 (2 and 4μg/kg), GLP-1 (500 and 1000nmol/kg), or PYY3-36 (12.5 and 25nmol/kg) was significantly less than that in saline-injected mice. In a separate cohort of mice, the higher doses of CCK-8 and GLP-1 and a greater dose of PYY3-36 (50nmol/kg) did not produce conditioned taste aversion to saccharin, suggesting that the doses of exogenous hormones in the present study do not cause aversive visceral distress. The present findings suggest that the systemic administration of these three gut hormones suppresses hedonic-driven sugar consumption due to the anorexic, but not aversive-visceral, effects of these hormones.
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16
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Lutz TA. Gut hormones such as amylin and GLP-1 in the control of eating and energy expenditure. INTERNATIONAL JOURNAL OF OBESITY SUPPLEMENTS 2016; 6:S15-S21. [PMID: 28685025 DOI: 10.1038/ijosup.2016.4] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
The control of meal size is the best studied aspect of the control of energy balance, and manipulation of this system constitutes a promising target to treat obesity. A major part of this control system is based on gastrointestinal hormones such as glucagon-like peptide-1 (GLP-1) or amylin, which are released in response to a meal and which limit the size of an ongoing meal. Both amylin and GLP-1 have also been shown to increase energy expenditure in experimental rodents, but mechanistically we know much less how this effect may be mediated, which brain sites may be involved, and what the physiological relevance of these findings may be. Most studies indicate that the effect of peripheral amylin is centrally mediated via the area postrema, but other brain areas, such as the ventral tegmental area, may also be involved. GLP-1's effect on eating seems to be mainly mediated by vagal afferents projecting to the caudal hindbrain. Chronic exposure to amylin, GLP-1 or their analogs decrease food intake and body weight gain. Next to the induction of satiation, amylin may also constitute an adiposity signal and in fact interact with the adiposity signal leptin. Amylin analogs are under clinical consideration for their effect to reduce food intake and body weight in humans, and similar to rodents, amylin analogs seem to be particularly active when combined with leptin analogs.
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Affiliation(s)
- T A Lutz
- Institute of Veterinary Physiology, Vetsuisse Faculty University of Zurich, Zurich, Switzerland.,Zurich Center of Integrative Human Physiology, University of Zurich, Zurich, Switzerland
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17
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Satiation and re-intake after partial withdrawal of gastric food contents: A dissociation effect in external lateral parabrachial lesioned rats. Brain Res Bull 2016; 127:126-133. [DOI: 10.1016/j.brainresbull.2016.09.006] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2016] [Revised: 09/06/2016] [Accepted: 09/09/2016] [Indexed: 11/19/2022]
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18
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Diz-Chaves Y, Gil-Lozano M, Toba L, Fandiño J, Ogando H, González-Matías LC, Mallo F. Stressing diabetes? The hidden links between insulinotropic peptides and the HPA axis. J Endocrinol 2016; 230:R77-94. [PMID: 27325244 DOI: 10.1530/joe-16-0118] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/26/2016] [Accepted: 06/20/2016] [Indexed: 12/25/2022]
Abstract
Diabetes mellitus exerts metabolic stress on cells and it provokes a chronic increase in the long-term activity of the hypothalamus-pituitary-adrenocortical (HPA) axis, perhaps thereby contributing to insulin resistance. GLP-1 receptor (GLP-1R) agonists are pleiotropic hormones that not only affect glycaemic and metabolic control, but they also produce many other effects including activation of the HPA axis. In fact, several of the most relevant effects of GLP-1 might involve, at least in part, the modulation of the HPA axis. Thus, the anorectic activity of GLP-1 could be mediated by increasing CRF at the hypothalamic level, while its lipolytic effects could imply a local increase in glucocorticoids and glucocorticoid receptor (GC-R) expression in adipose tissue. Indeed, the potent activation of the HPA axis by GLP-1R agonists occurs within the range of therapeutic doses and with a short latency. Interestingly, the interactions of GLP-1 with the HPA axis may underlie most of the effects of GLP-1 on food intake control, glycaemic metabolism, adipose tissue biology and the responses to stress. Moreover, such activity has been observed in animal models (mice and rats), as well as in normal humans and in type I or type II diabetic patients. Accordingly, better understanding of how GLP-1R agonists modulate the activity of the HPA axis in diabetic subjects, especially obese individuals, will be crucial to design new and more efficient therapies for these patients.
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Affiliation(s)
- Yolanda Diz-Chaves
- Laboratory of EndocrinologyCenter for Biomedical Research - CINBIO, University of Vigo, Vigo, Spain Instituto de Investigación Sanitaria Galicia Sur - IISGSVigo, Spain
| | - Manuel Gil-Lozano
- Laboratory of EndocrinologyCenter for Biomedical Research - CINBIO, University of Vigo, Vigo, Spain Instituto de Investigación Sanitaria Galicia Sur - IISGSVigo, Spain
| | - Laura Toba
- Laboratory of EndocrinologyCenter for Biomedical Research - CINBIO, University of Vigo, Vigo, Spain Instituto de Investigación Sanitaria Galicia Sur - IISGSVigo, Spain
| | - Juan Fandiño
- Laboratory of EndocrinologyCenter for Biomedical Research - CINBIO, University of Vigo, Vigo, Spain Instituto de Investigación Sanitaria Galicia Sur - IISGSVigo, Spain
| | - Hugo Ogando
- Laboratory of EndocrinologyCenter for Biomedical Research - CINBIO, University of Vigo, Vigo, Spain Instituto de Investigación Sanitaria Galicia Sur - IISGSVigo, Spain
| | - Lucas C González-Matías
- Laboratory of EndocrinologyCenter for Biomedical Research - CINBIO, University of Vigo, Vigo, Spain Instituto de Investigación Sanitaria Galicia Sur - IISGSVigo, Spain
| | - Federico Mallo
- Laboratory of EndocrinologyCenter for Biomedical Research - CINBIO, University of Vigo, Vigo, Spain Instituto de Investigación Sanitaria Galicia Sur - IISGSVigo, Spain
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20
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Campos CA, Bowen AJ, Schwartz MW, Palmiter RD. Parabrachial CGRP Neurons Control Meal Termination. Cell Metab 2016; 23:811-20. [PMID: 27166945 PMCID: PMC4867080 DOI: 10.1016/j.cmet.2016.04.006] [Citation(s) in RCA: 169] [Impact Index Per Article: 21.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/04/2015] [Revised: 02/17/2016] [Accepted: 04/04/2016] [Indexed: 01/09/2023]
Abstract
The lateral parabrachial nucleus is a conduit for visceral signals that cause anorexia. We previously identified a subset of neurons located in the external lateral parabrachial nucleus (PBel) that express calcitonin gene-related peptide (CGRP) and inhibit feeding when activated by illness mimetics. We report here that in otherwise normal mice, functional inactivation of CGRP neurons markedly increases meal size, with meal frequency being reduced in a compensatory manner, and renders mice insensitive to the anorexic effects of meal-related satiety peptides. Furthermore, CGRP neurons are directly innervated by orexigenic hypothalamic AgRP neurons, and photostimulation of AgRP fibers supplying the PBel delays satiation by inhibiting CGRP neurons, thereby contributing to AgRP-driven hyperphagia. By establishing a role for CGRP neurons in the control of meal termination and as a downstream mediator of feeding elicited by AgRP neurons, these findings identify a node in which hunger and satiety circuits interact to control feeding behavior.
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Affiliation(s)
- Carlos A Campos
- Department of Biochemistry, Howard Hughes Medical Institute, University of Washington, Seattle, WA 98195, USA.
| | - Anna J Bowen
- Department of Biochemistry, Howard Hughes Medical Institute, University of Washington, Seattle, WA 98195, USA
| | - Michael W Schwartz
- Department of Medicine, University of Washington, Seattle, WA 98195, USA
| | - Richard D Palmiter
- Department of Biochemistry, Howard Hughes Medical Institute, University of Washington, Seattle, WA 98195, USA.
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Eating in mice with gastric bypass surgery causes exaggerated activation of brainstem anorexia circuit. Int J Obes (Lond) 2016; 40:921-8. [PMID: 26984418 PMCID: PMC4899289 DOI: 10.1038/ijo.2016.38] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/17/2015] [Revised: 02/04/2016] [Accepted: 03/08/2016] [Indexed: 12/24/2022]
Abstract
Background/Objective Obesity and metabolic diseases are at an alarming level globally and increasingly affect children and adolescents. Gastric bypass and other bariatric surgeries have proven remarkably successful and are increasingly performed worldwide. Reduced desire to eat and changes in eating behavior and food choice account for most of the initial weight loss and diabetes remission after surgery, but the underlying mechanisms of altered gut-brain communication are unknown. Subjects/Methods To explore the potential involvement of a powerful brainstem anorexia pathway centered around the lateral parabrachial nucleus (lPBN) we measured meal-induced neuronal activation by means of c-Fos immunohistochemistry in a new high-fat diet-induced obese mouse model of Roux-en-Y gastric bypass (RYGB) at 10 and 40 days after RYGB or sham surgery. Results Voluntary ingestion of a meal 10 days after RYGB, but not after sham surgery, strongly and selectively activates calcitonin gene-related peptide neurons in the external lPBN as well as neurons in the nucleus tractus solitaries, area postrema, and medial amygdala. At 40 days after surgery, meal-induced activation in all these areas was greatly diminished and did not reach statistical significance. Conclusions The neural activation pattern and dynamics suggest a role of the brainstem anorexia pathway in the early effects of RYGB on meal size and food intake that may lead to adaptive neural and behavioral changes involved in the control of food intake and body weight at a lower level. However, selective inhibition of this pathway will be required for a more causal implication.
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Hay DL, Chen S, Lutz TA, Parkes DG, Roth JD. Amylin: Pharmacology, Physiology, and Clinical Potential. Pharmacol Rev 2016; 67:564-600. [PMID: 26071095 DOI: 10.1124/pr.115.010629] [Citation(s) in RCA: 237] [Impact Index Per Article: 29.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Amylin is a pancreatic β-cell hormone that produces effects in several different organ systems. Here, we review the literature in rodents and in humans on amylin research since its discovery as a hormone about 25 years ago. Amylin is a 37-amino-acid peptide that activates its specific receptors, which are multisubunit G protein-coupled receptors resulting from the coexpression of a core receptor protein with receptor activity-modifying proteins, resulting in multiple receptor subtypes. Amylin's major role is as a glucoregulatory hormone, and it is an important regulator of energy metabolism in health and disease. Other amylin actions have also been reported, such as on the cardiovascular system or on bone. Amylin acts principally in the circumventricular organs of the central nervous system and functionally interacts with other metabolically active hormones such as cholecystokinin, leptin, and estradiol. The amylin-based peptide, pramlintide, is used clinically to treat type 1 and type 2 diabetes. Clinical studies in obesity have shown that amylin agonists could also be useful for weight loss, especially in combination with other agents.
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Affiliation(s)
- Debbie L Hay
- School of Biological Sciences, Maurice Wilkins Centre for Molecular Biodiscovery and Centre for Brain Research, University of Auckland, Auckland, New Zealand (D.L.H.); Amylin Pharmaceuticals LLC, San Diego, California (S.C., D.G.P.); Institute of Veterinary Physiology, Institute of Laboratory Animal Sciences and Centre for Integrative Human Physiology, University of Zurich, Zurich, Switzerland (T.A.L.); and Intercept Pharmaceuticals, Inc., San Diego, California (J.D.R.)
| | - Steve Chen
- School of Biological Sciences, Maurice Wilkins Centre for Molecular Biodiscovery and Centre for Brain Research, University of Auckland, Auckland, New Zealand (D.L.H.); Amylin Pharmaceuticals LLC, San Diego, California (S.C., D.G.P.); Institute of Veterinary Physiology, Institute of Laboratory Animal Sciences and Centre for Integrative Human Physiology, University of Zurich, Zurich, Switzerland (T.A.L.); and Intercept Pharmaceuticals, Inc., San Diego, California (J.D.R.)
| | - Thomas A Lutz
- School of Biological Sciences, Maurice Wilkins Centre for Molecular Biodiscovery and Centre for Brain Research, University of Auckland, Auckland, New Zealand (D.L.H.); Amylin Pharmaceuticals LLC, San Diego, California (S.C., D.G.P.); Institute of Veterinary Physiology, Institute of Laboratory Animal Sciences and Centre for Integrative Human Physiology, University of Zurich, Zurich, Switzerland (T.A.L.); and Intercept Pharmaceuticals, Inc., San Diego, California (J.D.R.)
| | - David G Parkes
- School of Biological Sciences, Maurice Wilkins Centre for Molecular Biodiscovery and Centre for Brain Research, University of Auckland, Auckland, New Zealand (D.L.H.); Amylin Pharmaceuticals LLC, San Diego, California (S.C., D.G.P.); Institute of Veterinary Physiology, Institute of Laboratory Animal Sciences and Centre for Integrative Human Physiology, University of Zurich, Zurich, Switzerland (T.A.L.); and Intercept Pharmaceuticals, Inc., San Diego, California (J.D.R.)
| | - Jonathan D Roth
- School of Biological Sciences, Maurice Wilkins Centre for Molecular Biodiscovery and Centre for Brain Research, University of Auckland, Auckland, New Zealand (D.L.H.); Amylin Pharmaceuticals LLC, San Diego, California (S.C., D.G.P.); Institute of Veterinary Physiology, Institute of Laboratory Animal Sciences and Centre for Integrative Human Physiology, University of Zurich, Zurich, Switzerland (T.A.L.); and Intercept Pharmaceuticals, Inc., San Diego, California (J.D.R.)
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Hindmarch CCT, Ferguson AV. Physiological roles for the subfornical organ: a dynamic transcriptome shaped by autonomic state. J Physiol 2015; 594:1581-9. [PMID: 26227400 DOI: 10.1113/jp270726] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2015] [Accepted: 07/26/2015] [Indexed: 12/15/2022] Open
Abstract
The subfornical organ (SFO) is a circumventricular organ recognized for its ability to sense and integrate hydromineral and hormonal circulating fluid balance signals, information which is transmitted to central autonomic nuclei to which SFO neurons project. While the role of SFO was once synonymous with physiological responses to osmotic, volumetric and cardiovascular challenge, recent data suggest that SFO neurons also sense and integrate information from circulating signals of metabolic status. Using microarrays, we have confirmed the expression of receptors already described in the SFO, and identified many novel transcripts expressed in this circumventricular organ including receptors for many of the critical circulating energy balance signals such as adiponectin, apelin, endocannabinoids, leptin, insulin and peptide YY. This transcriptome analysis also identified SFO transcripts, the expressions of which are significantly changed by either 72 h dehydration, or 48 h starvation, compared to fed and euhydrated controls. Expression and potential roles for many of these targets are yet to be confirmed and elucidated. Subsequent validation of data for adiponectin and leptin receptors confirmed that receptors for both are expressed in the SFO, that discrete populations of neurons in this tissue are functionally responsive to these adipokines, and that such responsiveness is regulated by physiological state. Thus, transcriptomic analysis offers great promise for understanding the integrative complexity of these physiological systems, especially with development of technologies allowing description of the entire transcriptome of single, carefully phenotyped, SFO neurons. These data will ultimately elucidate mechanisms through which these uniquely positioned neurons respond to and integrate complex circulating signals.
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Affiliation(s)
- Charles Colin Thomas Hindmarch
- School of Clinical Sciences, Dorothy Hodgkin Building, University of Bristol, Bristol, BS1 3NY, UK.,Department of Physiology, Faculty of Medicine, University of Malaya, 50603, Kuala Lumpur, Malaysia
| | - Alastair V Ferguson
- Department of Biomedical and Molecular Sciences, Queen's University, Kingston, ON, Canada, K7L 3N6
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Lutz TA, Meyer U. Amylin at the interface between metabolic and neurodegenerative disorders. Front Neurosci 2015; 9:216. [PMID: 26136651 PMCID: PMC4468610 DOI: 10.3389/fnins.2015.00216] [Citation(s) in RCA: 67] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2015] [Accepted: 05/29/2015] [Indexed: 12/14/2022] Open
Abstract
The pancreatic peptide amylin is best known for its role as a satiation hormone in the control of food intake and as the major component of islet amyloid deposits in the pancreatic islets of patients with type 2 diabetes mellitus (T2DM). Epidemiological studies have established a clear association between metabolic and neurodegenerative disorders in general, and between T2DM and Alzheimer's disease (AD) in particular. Here, we discuss that amylin may be an important player acting at the interface between these metabolic and neurodegenerative disorders. Abnormal amylin production is a hallmark peripheral pathology both in the early (pre-diabetic) and late phases of T2DM, where hyperamylinemic (early phase) and hypoamylinemic (late phase) conditions coincide with hyper- and hypo-insulinemia, respectively. Moreover, there are notable biochemical similarities between amylin and β-amyloids (Aβ), which are both prone to amyloid plaque formation and to cytotoxic effects. Amylin's propensity to form amyloid plaques is not restricted to pancreatic islet cells, but readily extends to the CNS, where it has been found to co-localize with Aβ plaques in at least a subset of AD patients. Hence, amylin may constitute a “second amyloid” in neurodegenerative disorders such as AD. We further argue that hyperamylinemic conditions may be more relevant for the early processes of amyloid formation in the CNS, whereas hypoamylinemic conditions may be more strongly associated with late stages of central amyloid pathologies. Advancing our understanding of these temporal relationships may help to establish amylin-based interventions in the treatment of AD and other neurodegenerative disorders with metabolic comorbidities.
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Affiliation(s)
- Thomas A Lutz
- Institute of Veterinary Physiology, University of Zurich Zurich, Switzerland ; Zurich Center of Integrative Human Physiology, University of Zurich Zurich, Switzerland
| | - Urs Meyer
- Institute of Veterinary Pharmacology and Toxicology, University of Zurich Zurich, Switzerland
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Münzberg H, Laque A, Yu S, Rezai-Zadeh K, Berthoud HR. Appetite and body weight regulation after bariatric surgery. Obes Rev 2015; 16 Suppl 1:77-90. [PMID: 25614206 PMCID: PMC4784979 DOI: 10.1111/obr.12258] [Citation(s) in RCA: 77] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Bariatric surgery continues to be remarkably efficient in treating obesity and type 2 diabetes mellitus and a debate has started whether it should remain the last resort only or also be used for the prevention of metabolic diseases. Intense research efforts in humans and rodent models are underway to identify the critical mechanisms underlying the beneficial effects with a view towards non-surgical treatment options. This non-systematic review summarizes and interprets some of this literature, with an emphasis on changes in the controls of appetite. Contrary to earlier views, surgery-induced reduction of energy intake and subsequent weight loss appear to be the main drivers for rapid improvements of glycaemic control. The mechanisms responsible for suppression of appetite, particularly in the face of the large weight loss, are not well understood. Although a number of changes in food choice, taste functions, hedonic evaluation, motivation and self-control have been documented in both humans and rodents after surgery, their importance and relative contribution to diminished appetite has not yet been demonstrated. Furthermore, none of the major candidate mechanisms postulated in mediating surgery-induced changes from the gut and other organs to the brain, such as gut hormones and sensory neuronal pathways, have been confirmed yet. Future research efforts should focus on interventional rather than descriptive approaches in both humans and rodent models.
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Affiliation(s)
- H Münzberg
- Pennington Biomedical Research Center, Louisiana State University System, Baton Rouge, LA, USA
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26
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Voigt JP, Fink H. Serotonin controlling feeding and satiety. Behav Brain Res 2015; 277:14-31. [DOI: 10.1016/j.bbr.2014.08.065] [Citation(s) in RCA: 192] [Impact Index Per Article: 21.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2014] [Revised: 08/14/2014] [Accepted: 08/19/2014] [Indexed: 02/06/2023]
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Wright FL, Rodgers RJ. Behavioural profile of exendin-4/naltrexone dose combinations in male rats during tests of palatable food consumption. Psychopharmacology (Berl) 2014; 231:3729-44. [PMID: 24682505 DOI: 10.1007/s00213-014-3507-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/07/2013] [Accepted: 02/12/2014] [Indexed: 12/25/2022]
Abstract
RATIONALE The glucagon-like peptide 1 receptor (GLP-1R) agonist exendin-4 potently suppresses food intake in animals and humans. However, little is known about the behavioural specificity of this effect either when administered alone or when co-administered with another anorectic agent. OBJECTIVES The present study characterises the effects of exendin-4, both alone and in combination with naltrexone, on behaviours displayed by male rats during tests with palatable mash. METHODS Experiment 1 examined the dose-response effects of exendin-4 (0.025-2.5 μg/kg, IP), while experiment 2 profiled the effects of low-dose combinations of the peptide (0.025 and 0.25 μg/kg) and naltrexone (0.1 mg/kg). RESULTS In experiment 1, exendin-4 dose dependently suppressed food intake as well as the frequency and rate of eating. However, these effects were accompanied by dose-dependent reductions in all active behaviours and, at 2.5 μg/kg, a large increase in resting and disruption of the behavioural satiety sequence (BSS). In experiment 2, while exendin-4 (0.25 μg/kg) and naltrexone each produced a significant reduction in intake and feeding behaviour (plus an acceleration in the BSS), co-treatment failed to produce stronger effects than those seen in response to either compound alone. CONCLUSION Similarities between the behavioural signature of exendin-4 and that previously reported for the emetic agent lithium chloride would suggest that exendin-4 anorexia is related to the aversive effects of the peptide. Furthermore, as low-dose combinations of the peptide with naltrexone failed to produce an additive/synergistic anorectic effect, this particular co-treatment strategy would not appear to have therapeutic significance.
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Affiliation(s)
- F L Wright
- Behavioural Neuroscience Laboratory, Institute of Psychological Sciences, University of Leeds, Leeds, LS2 9JT, UK, England
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28
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Qiu WQ, Zhu H. Amylin and its analogs: a friend or foe for the treatment of Alzheimer's disease? Front Aging Neurosci 2014; 6:186. [PMID: 25120481 PMCID: PMC4114192 DOI: 10.3389/fnagi.2014.00186] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2014] [Accepted: 07/09/2014] [Indexed: 12/20/2022] Open
Abstract
Amylin, a gut-brain axis hormone, and amyloid-beta peptides (Aβ), a major component of the Alzheimer's disease (AD) brain, share several features, including similar β-sheet secondary structures, binding to the same receptor and being degraded by the same protease, insulin degrading enzyme (IDE). However, while amylin readily crosses the blood brain barrier (BBB) and mediates several activities including improving glucose metabolism, relaxing cerebrovascular structure, modulating inflammatory reaction and perhaps enhancing neural regeneration, Aβ has no known physiological functions. Thus, abundant Aβ in the AD brain could block or interfere with the binding of amylin to its receptor and hinder its functions. Recent studies using animal models for AD demonstrate that amylin and its analog reduce the AD pathology in the brain and improve cognitive impairment in AD. Given that, in addition to amyloid plaques and neurofibrillary tangles, perturbed cerebral glucose metabolism and cerebrovascular damage are the hallmarks of the AD brain, we propose that giving exogenous amylin type peptides have the potential to become a new avenue for the diagnosis and therapeutic of AD. Although amylin's property of self-aggregation may be a limitation to developing it as a therapeutic for AD, its clinical analog, pramlintide containing 3 amino acid differences from amylin, does not aggregate like human amylin, but more potently mediates amylin's activities in the brain. Pramlintide is an effective drug for diabetes with a favorable profile of safety. Thus a randomized, double-blind, placebo-controlled clinical trial should be conducted to examine the efficacy of pramlintide for AD. This review summarizes the knowledge and findings on amylin type peptides and discuss pros and cons for their potential for AD.
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Affiliation(s)
- Wei Qiao Qiu
- Department of Psychiatry, Boston University School of Medicine Boston, MA, USA ; Department of Pharmacology and Experimental Therapeutics, Boston University School of Medicine Boston, MA, USA ; Alzheimer's Disease Center, Boston University School of Medicine Boston, MA, USA
| | - Haihao Zhu
- Department of Pharmacology and Experimental Therapeutics, Boston University School of Medicine Boston, MA, USA
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29
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Braegger FE, Asarian L, Dahl K, Lutz TA, Boyle CN. The role of the area postrema in the anorectic effects of amylin and salmon calcitonin: behavioral and neuronal phenotyping. Eur J Neurosci 2014; 40:3055-66. [PMID: 25040689 DOI: 10.1111/ejn.12672] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2014] [Revised: 06/11/2014] [Accepted: 06/16/2014] [Indexed: 11/27/2022]
Abstract
Amylin reduces meal size by activating noradrenergic neurons in the area postrema (AP). Neurons in the AP also mediate the eating-inhibitory effects of salmon calcitonin (sCT), a potent amylin agonist, but the phenotypes of the neurons mediating its effect are unknown. Here we investigated whether sCT activates similar neuronal populations to amylin, and if its anorectic properties also depend on AP function. Male rats underwent AP lesion (APX) or sham surgery. Meal patterns were analysed under ad libitum and post-deprivation conditions. The importance of the AP in mediating the anorectic action of sCT was examined in feeding experiments of dose-response effects of sCT in APX vs. sham rats. The effect of sCT to induce Fos expression was compared between surgery groups, and relative to amylin. The phenotype of Fos-expressing neurons in the brainstem was examined by testing for the co-expression of dopamine beta hydroxylase (DBH) or tryptophan hydroxylase (TPH). By measuring the apposition of vesicular glutamate transporter-2 (VGLUT2)-positive boutons, potential glutamatergic input to amylin- and sCT-activated AP neurons was compared. Similar to amylin, an intact AP was necessary for sCT to reduce eating. Further, co-expression between Fos activation and DBH after amylin or sCT did not differ markedly, while co-localization of Fos and TPH was minor. Approximately 95% of neurons expressing Fos and DBH after amylin or sCT treatment were closely apposed to VGLUT2-positive boutons. Our study suggests that the hindbrain pathways engaged by amylin and sCT share many similarities, including the mediation by AP neurons.
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Affiliation(s)
- Fiona E Braegger
- Institute of Veterinary Physiology, University of Zurich, Zurich, 8057, Switzerland
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30
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Mietlicki-Baase EG, Hayes MR. Amylin activates distributed CNS nuclei to control energy balance. Physiol Behav 2014; 136:39-46. [PMID: 24480072 DOI: 10.1016/j.physbeh.2014.01.013] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2013] [Revised: 01/13/2014] [Accepted: 01/16/2014] [Indexed: 01/25/2023]
Abstract
Amylin is a pancreas-derived neuropeptide that acts in the central nervous system (CNS) to reduce food intake. Much of the literature describing the anorectic effects of amylin are focused on amylin's actions in the area postrema, a hindbrain circumventricular structure. Although the area postrema is certainly an important site that mediates the intake-suppressive effects of amylin, several pieces of evidence indicate that amylin may also promote negative energy balance through action in additional CNS nuclei, including hypothalamic and mesolimbic structures. Therefore, this review highlights the distributed neural network mediating the feeding effects of amylin signaling with special attention being devoted to the recent discovery that the ventral tegmental area is physiologically relevant for amylin-mediated control of feeding. The production of amylin by alternative, extra-pancreatic sources and its potential relevance to food intake regulation is also considered. Finally, the utility of amylin and amylin-like compounds as a component of combination pharmacotherapies for the treatment of obesity is discussed.
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Affiliation(s)
- Elizabeth G Mietlicki-Baase
- Translational Neuroscience Program, Department of Psychiatry, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA.
| | - Matthew R Hayes
- Translational Neuroscience Program, Department of Psychiatry, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
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Gu G, Roland B, Tomaselli K, Dolman CS, Lowe C, Heilig JS. Glucagon-like peptide-1 in the rat brain: distribution of expression and functional implication. J Comp Neurol 2013; 521:2235-61. [PMID: 23238833 DOI: 10.1002/cne.23282] [Citation(s) in RCA: 82] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2012] [Revised: 09/17/2012] [Accepted: 12/07/2012] [Indexed: 12/20/2022]
Abstract
Glucagon-like-peptide 1 (GLP-1) is expressed not only in gut endocrine cells, but also in cells in the caudal brainstem and taste buds. To better understand the functions of central GLP-1, GLP-1 expression was immunohistochemically profiled in normal rat brain and its distribution correlated with FOS induction following systemic administration of a GLP-1 receptor agonist, exendin-4. In the present study, only a small number of GLP-1-immunoreactive cell bodies were observed in the nucleus of the solitary tract (NTS). However, these neurons send abundant projections to other regions of the brain, in particular the forebrain, including the paraventricular and dorsomedial nuclei of the hypothalamus, the central nucleus of the amygdala, the oval nucleus of the bed nuclei of the stria terminalis, and the paraventricular nucleus of the thalamus. Intraperitoneal administration of exendin-4 resulted in extensive FOS expression in areas of the forebrain and the hindbrain. In the forebrain, FOS expression was largely confined to regions where a high density of GLP-1-immunoreactive terminals was also localized. The majority of GLP-1-immunoreactive cells in the NTS were not FOS-positive. FOS-positive cells appeared to represent a different population from those expressing GLP-1. Thus, GLP-1-containing neurons in the brainstem may not be involved in receiving and relaying to other regions of the brain the physiological signals of prandial GLP-1 secreted by intestinal L-cells. Projections of GLP-1-containing neurons to the distinctive structures in the forebrain imply that central GLP-1 may play an important role in the behavioral and metabolic integration of autonomic control and arousal in the rat.
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Affiliation(s)
- Guibao Gu
- Amylin Pharmaceuticals, San Diego, California 92121, USA.
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32
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Lockie SH. Glucagon-like peptide-1 receptor in the brain: role in neuroendocrine control of energy metabolism and treatment target for obesity. J Neuroendocrinol 2013; 25:597-604. [PMID: 23590331 DOI: 10.1111/jne.12039] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/02/2012] [Revised: 03/15/2013] [Accepted: 04/07/2013] [Indexed: 12/01/2022]
Abstract
The central glucagon-like peptide (GLP)-1 receptor mediates a number of metabolic processes, including feeding, body weight and glucose homeostasis. More recently, roles in energy expenditure and reward pathway modulation have been described. GLP-1 receptor agonism promotes insulin release and is currently used to treat type 2 diabetes humans, with a common side effect being weight loss. It is likely that many of these metabolic effects are mediated by GLP-1Rs located in the central nervous system, throughout areas known to be important in control of energy homeostasis. The physiological role of the GLP-1 receptor signalling in each of these brain nuclei is becoming clearer and the GLP-1 system appears to act as an integrator of peripheral energy availability and effector of metabolic regulation. This makes it an attractive target for obesity therapies, with excellent pre-clinical efficacy seen in molecules combining GLP-1 receptor agonism with glucagon receptor agonism. This review discusses what is known about the functions of the GLP-1 receptor in the central nervous system, and highlights the ways that this system may be targeted for development of new obesity therapeutics.
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Affiliation(s)
- S H Lockie
- Physiology, Monash University, 3800 Clayton, Australia.
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Fernandes-Santos C, Zhang Z, Morgan DA, Guo DF, Russo AF, Rahmouni K. Amylin acts in the central nervous system to increase sympathetic nerve activity. Endocrinology 2013; 154:2481-8. [PMID: 23645151 PMCID: PMC3689285 DOI: 10.1210/en.2012-2172] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The pancreatic hormone amylin acts in the central nervous system (CNS) to decrease food intake and body weight. We hypothesized that amylin action in the CNS promotes energy expenditure by increasing the activity of the sympathetic nervous system. In mice, ip administration of amylin significantly increased c-Fos immunoreactivity in hypothalamic and brainstem nuclei. In addition, mice treated with intracerebroventricular (icv) amylin (0.1 and 0.2 nmol) exhibited a dose-related decrease in food intake and body weight, measured 4 and 24 hours after treatment. The icv injection of amylin also increased body temperature in mice. Using direct multifiber sympathetic nerve recording, we found that icv amylin elicited a significant and dose-dependent increase in sympathetic nerve activity (SNA) subserving thermogenic brown adipose tissue (BAT). Of note, icv injection of amylin also evoked a significant and dose-related increase in lumbar and renal SNA. Importantly, icv pretreatment with the amylin receptor antagonist AC187 (20 nmol) abolished the BAT SNA response induced by icv amylin, indicating that the sympathetic effects of amylin are receptor-mediated. Conversely, icv amylin-induced BAT SNA response was enhanced in mice overexpressing the amylin receptor subunit, RAMP1 (receptor-activity modifying protein 1), in the CNS. Our data demonstrate that CNS action of amylin regulates sympathetic nerve outflow to peripheral tissues involved in energy balance and cardiovascular function.
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Affiliation(s)
- Caroline Fernandes-Santos
- Department of Internal Medicine, University of Iowa Carver College of Medicine, Iowa City, IA 52242, USA
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Lutz TA. The interaction of amylin with other hormones in the control of eating. Diabetes Obes Metab 2013; 15:99-111. [PMID: 22862822 DOI: 10.1111/j.1463-1326.2012.01670.x] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/20/2012] [Revised: 07/20/2012] [Accepted: 07/28/2012] [Indexed: 11/30/2022]
Abstract
Twenty years of research established amylin as an important control of energy homeostasis. Amylin controls nutrient and energy fluxes by reducing energy intake, by modulating nutrient utilization via an inhibition of postprandial glucagon secretion and by increasing energy disposal via a prevention of compensatory decreases of energy expenditure in weight reduced individuals. Like many other gastrointestinal hormones, amylin is secreted in response to meals and it reduces eating by promoting meal-ending satiation. Not surprisingly, amylin interacts with many of these hormones to control eating. These interactions seem to occur at different levels because amylin seems to mediate the eating inhibitory effect of some of these gastrointestinal hormones, and the combination of some of these hormones seems to lead to a stronger reduction in eating than single hormones alone. Amylin's effect on eating is thought to be mediated by a stimulation of specific amylin receptors in the area postrema. Secondary brain sites that were defined to mediate amylin action - and hence potential additional sites of interaction with other hormones - include the nucleus of the solitary tract, the lateral parabrachial nucleus, the lateral hypothalamic area and other hypothalamic nuclei. The focus of this review is to summarize the current knowledge of amylin interactions in the control of eating. In most cases, these interactions have only been studied at a descriptive rather than a mechanistic level and despite the clear knowledge on primary sites of amylin action, the interaction sites between amylin and other hormones are often unknown.
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Affiliation(s)
- T A Lutz
- Institute of Veterinary Physiology, University of Zurich, Zurich, Switzerland.
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Maniscalco JW, Kreisler AD, Rinaman L. Satiation and stress-induced hypophagia: examining the role of hindbrain neurons expressing prolactin-releasing Peptide or glucagon-like Peptide 1. Front Neurosci 2013; 6:199. [PMID: 23346044 PMCID: PMC3549516 DOI: 10.3389/fnins.2012.00199] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2012] [Accepted: 12/31/2012] [Indexed: 12/20/2022] Open
Abstract
Neural circuits distributed within the brainstem, hypothalamus, and limbic forebrain interact to control food intake and energy balance under normal day-to-day conditions, and in response to stressful conditions under which homeostasis is threatened. Experimental studies using rats and mice have generated a voluminous literature regarding the functional organization of circuits that inhibit food intake in response to satiety signals, and in response to stress. Although the central neural bases of satiation and stress-induced hypophagia often are studied and discussed as if they were distinct, we propose that both behavioral states are generated, at least in part, by recruitment of two separate but intermingled groups of caudal hindbrain neurons. One group comprises a subpopulation of noradrenergic (NA) neurons within the caudal nucleus of the solitary tract (cNST; A2 cell group) that is immunopositive for prolactin-releasing peptide (PrRP). The second group comprises non-adrenergic neurons within the cNST and nearby reticular formation that synthesize glucagon-like peptide 1 (GLP-1). Axonal projections from PrRP and GLP-1 neurons target distributed brainstem and forebrain regions that shape behavioral, autonomic, and endocrine responses to actual or anticipated homeostatic challenge, including the challenge of food intake. Evidence reviewed in this article supports the view that hindbrain PrRP and GLP-1 neurons contribute importantly to satiation and stress-induced hypophagia by modulating the activity of caudal brainstem circuits that control food intake. Hindbrain PrRP and GLP-1 neurons also engage hypothalamic and limbic forebrain networks that drive parallel behavioral and endocrine functions related to food intake and homeostatic challenge, and modulate conditioned and motivational aspects of food intake.
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Affiliation(s)
- James W Maniscalco
- Department of Neuroscience, University of Pittsburgh Pittsburgh, PA, USA
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Tao YX, Yuan ZH, Xie J. G Protein-Coupled Receptors as Regulators of Energy Homeostasis. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2013; 114:1-43. [DOI: 10.1016/b978-0-12-386933-3.00001-7] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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The receptive function of hypothalamic and brainstem centres to hormonal and nutrient signals affecting energy balance. Proc Nutr Soc 2012; 71:463-77. [PMID: 22931748 DOI: 10.1017/s0029665112000778] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The hypothalamic arcuate nucleus (ARC) and the area postrema (AP) represent targets for hormonal and metabolic signals involved in energy homoeostasis, e.g. glucose, amylin, insulin, leptin, peptide YY (PYY), glucagon-like peptide 1 (GLP-1) and ghrelin. Orexigenic neuropeptide Y expressing ARC neurons are activated by food deprivation and inhibited by feeding in a nutrient-dependent manner. PYY and leptin also reverse or prevent fasting-induced activation of the ARC. Interestingly, hypothalamic responses to fasting are blunted in different models of obesity (e.g. diet-induced obesity (DIO) or late-onset obesity). The AP also responds to feeding-related signals. The pancreatic hormone amylin acts via the AP to control energy intake. Amylin-sensitive AP neurons are also glucose-responsive. Furthermore, diet-derived protein attenuates amylin responsiveness suggesting a modulation of AP sensitivity by macronutrient supply. This review gives an overview of the receptive function of the ARC and the AP to hormonal and nutritional stimuli involved in the control of energy balance and the possible implications in the context of obesity. Collectively, there is consistency between the neurophysiological actions of these stimuli and their effects on energy homoeostasis under experimental conditions. However, surprisingly little progress has been made in the development of effective pharmacological approaches against obesity. A promising way to improve effectiveness involves combination treatments (e.g. amylin/leptin agonists). Hormonal alterations (e.g. GLP-1 and PYY) are also considered to mediate body weight loss observed in obese patients receiving bariatric surgery. The effects of hormonal and nutritional signals and their interactions might hold the potential to develop poly-mechanistic therapeutic strategies against obesity.
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Roth JD, Erickson MR, Chen S, Parkes DG. GLP-1R and amylin agonism in metabolic disease: complementary mechanisms and future opportunities. Br J Pharmacol 2012; 166:121-36. [PMID: 21671898 DOI: 10.1111/j.1476-5381.2011.01537.x] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
The discoveries of the incretin hormone glucagon-like peptide-1 (GLP-1) and the β-cell hormone amylin have translated into hormone-based therapies for diabetes. Both classes of molecules also exhibit weight-lowering effects and have been investigated for their anti-obesity potential. In the present review, we explore the mechanisms underlying the physiological and pharmacological actions of GLP-1 and amylin agonism. Despite their similarities (e.g. both molecular classes slow gastric emptying, decrease glucagon and inhibit food intake), there are important distinctions between the central and/or peripheral pathways that mediate their effects on glycaemia and energy balance. We suggest that understanding the similarities and differences between these molecules holds important implications for the development of novel, combination-based therapies, which are increasingly the norm for diabetes/metabolic disease. Finally, the future of GLP-1- and amylin agonist-based therapeutics is discussed.
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Harrold JA, Dovey TM, Blundell JE, Halford JC. CNS regulation of appetite. Neuropharmacology 2012; 63:3-17. [DOI: 10.1016/j.neuropharm.2012.01.007] [Citation(s) in RCA: 103] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2011] [Revised: 01/05/2012] [Accepted: 01/10/2012] [Indexed: 12/14/2022]
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Lutz TA. Control of energy homeostasis by amylin. Cell Mol Life Sci 2012; 69:1947-65. [PMID: 22193913 PMCID: PMC11114503 DOI: 10.1007/s00018-011-0905-1] [Citation(s) in RCA: 99] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2011] [Revised: 11/13/2011] [Accepted: 12/06/2011] [Indexed: 02/04/2023]
Abstract
Amylin is an important control of nutrient fluxes because it reduces energy intake, modulates nutrient utilization by inhibiting postprandial glucagon secretion, and increases energy disposal by preventing compensatory decreases of energy expenditure in weight-reduced individuals. The best investigated function of amylin which is cosecreted with insulin is to reduce eating by promoting meal-ending satiation. This effect is thought to be mediated by a stimulation of specific amylin receptors in the area postrema. Secondary brain sites to mediate amylin action include the nucleus of the solitary tract and the lateral parabrachial nucleus, which convey the neural signal to the lateral hypothalamic area and other hypothalamic nuclei. Amylin may also signal adiposity because plasma levels of amylin are increased in adiposity and because higher amylin concentrations in the brain result in reduced body weight gain and adiposity, while amylin receptor antagonists increase body adiposity. The central mechanisms involved in amylin's effect on energy expenditure are much less known. A series of recent experiments in animals and humans indicate that amylin is a promising option for anti-obesity therapy especially in combination with other hormones. The most extensive dataset is available for the combination therapy of amylin and leptin. Ongoing research focuses on the mechanisms of these interactions.
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Affiliation(s)
- Thomas A Lutz
- Institute of Veterinary Physiology, Vetsuisse Faculty University of Zurich, Switzerland.
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Müller TD, Sullivan LM, Habegger K, Yi CX, Kabra D, Grant E, Ottaway N, Krishna R, Holland J, Hembree J, Perez-Tilve D, Pfluger PT, DeGuzman MJ, Siladi ME, Kraynov VS, Axelrod DW, DiMarchi R, Pinkstaff JK, Tschöp MH. Restoration of leptin responsiveness in diet-induced obese mice using an optimized leptin analog in combination with exendin-4 or FGF21. J Pept Sci 2012; 18:383-93. [PMID: 22565812 DOI: 10.1002/psc.2408] [Citation(s) in RCA: 122] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2012] [Revised: 03/02/2012] [Accepted: 03/05/2012] [Indexed: 11/07/2022]
Abstract
The identification of leptin as a mediator of body weight regulation provided much initial excitement for the treatment of obesity. Unfortunately, leptin monotherapy is insufficient in reversing obesity in rodents or humans. Recent findings suggest that amylin is able to restore leptin sensitivity and when used in combination with leptin enhances body weight loss in obese rodents and humans. However, as the uniqueness of this combination therapy remains unclear, we assessed whether co-administration of leptin with other weight loss-inducing hormones equally restores leptin responsiveness in diet-induced obese (DIO) mice. Accordingly, we report here the design and characterization of a series of site-specifically enhanced leptin analogs of high potency and sustained action that, when administered in combination with exendin-4 or fibroblast growth factor 21 (FGF21), restores leptin responsiveness in DIO mice after an initial body weight loss of 30%. Using either combination, body weight loss was enhanced compared with either exendin-4 or FGF21 monotherapy, and leptin alone was sufficient to maintain the reduced body weight. In contrast, leptin monotherapy proved ineffective when identical weight loss was induced by caloric restriction alone over a comparable time. Accordingly, we find that a hypothalamic counter-regulatory response to weight loss, assessed using changes in hypothalamic agouti related peptide (AgRP) levels, is triggered by caloric restriction, but blunted by treatment with exendin-4. We conclude that leptin re-sensitization requires pharmacotherapy but does not appear to be restricted to a unique signaling pathway. Our findings provide preclinical evidence that high activity, long-acting leptin analogs are additively efficacious when used in combination with other weight-lowering agents.
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Affiliation(s)
- Timo D Müller
- Metabolic Disease Institute, Division of Endocrinology, Diabetes & Metabolism, Department of Internal Medicine, College of Medicine, University of Cincinnati, Cincinnati, OH 45230, USA
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Ladenheim EE. Gastrointestinal regulatory peptides and central nervous system mechanisms of weight control. Curr Opin Endocrinol Diabetes Obes 2012; 19:13-8. [PMID: 22157396 DOI: 10.1097/med.0b013e32834ea723] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
PURPOSE OF REVIEW This review focuses on recent advances in understanding the multiple roles of gastrointestinal peptides in the control of food intake and body weight with specific emphasis on ghrelin, amylin and glucagon-like peptide 1. RECENT FINDINGS Recent studies support a role for ghrelin, amylin and glucagon-like peptide 1 in short-term and long-term effects on food intake and body weight. Apart from contributing to energy homeostasis, ghrelin's participation in reward and sensory processing has been the focus of much recent work. New findings on amylin's effects on food intake and energy balance provide further support for its role in meal-related food intake and suggest that it may also function as an adiposity signal. New investigations on the role of central and peripheral glucagon-like peptide 1 receptors in mediating the anorexic effects of glucagon-like peptide 1 have suggested that they differentially contribute to short-term and long term effects on food intake. SUMMARY Gastrointestinal peptides can influence food intake through mechanisms that involve short-term meal-related effects or through activation of central pathways involved in energy balance. An appreciation of the multiple actions of gastrointestinal peptides on food intake will aid in developing new strategies for weight management.
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Affiliation(s)
- Ellen E Ladenheim
- Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA.
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Potes CS, Boyle CN, Wookey PJ, Riediger T, Lutz TA. Involvement of the extracellular signal-regulated kinase 1/2 signaling pathway in amylin's eating inhibitory effect. Am J Physiol Regul Integr Comp Physiol 2012; 302:R340-51. [DOI: 10.1152/ajpregu.00380.2011] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Peripheral amylin inhibits eating via the area postrema (AP). Because amylin activates the extracellular-signal regulated kinase 1/2 (ERK) pathway in some tissues, and because ERK1/2 phosphorylation (pERK) leads to acute neuronal responses, we postulated that it may be involved in amylin's eating inhibitory effect. Amylin-induced ERK phosphorylation (pERK) was investigated by immunohistochemistry in brain sections containing the AP. pERK-positive AP neurons were double-stained for the calcitonin 1a/b receptor, which is part of the functional amylin-receptor. AP sections were also phenotyped using dopamine-β-hydroxylase (DBH) as a marker of noradrenergic neurons. The effect of fourth ventricular administration of the ERK cascade blocker U0126 on amylin's eating inhibitory action was tested in feeding trials. The number of pERK-positive neurons in the AP was highest ∼10–15 min after amylin treatment; the effect appeared to be dose-dependent (5–20 μg/kg amylin). A portion of pERK-positive neurons in the AP carried the amylin-receptor and 22% of the pERK-positive neurons were noradrenergic. Pretreatment of rats with U0126 decreased the number of pERK-positive neurons in the AP after amylin injection. U0126 also attenuated the ability of amylin to reduce eating, at least when the animals had been fasted 24 h prior to the feeding trial. Overall, our results suggest that amylin directly stimulates pERK in AP neurons in a time- and dose-dependent manner. Part of the AP neurons displaying pERK were noradrenergic. At least under fasting conditions, pERK was shown to be a necessary part in the signaling cascade mediating amylin's anorectic effect.
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Affiliation(s)
- Catarina Soares Potes
- Institute of Veterinary Physiology and Zurich Center for Integrative Human Physiology, Vetsuisse Faculty University of Zurich, Zurich Switzerland; and
| | - Christina Neuner Boyle
- Institute of Veterinary Physiology and Zurich Center for Integrative Human Physiology, Vetsuisse Faculty University of Zurich, Zurich Switzerland; and
| | | | - Thomas Riediger
- Institute of Veterinary Physiology and Zurich Center for Integrative Human Physiology, Vetsuisse Faculty University of Zurich, Zurich Switzerland; and
| | - Thomas Alexander Lutz
- Institute of Veterinary Physiology and Zurich Center for Integrative Human Physiology, Vetsuisse Faculty University of Zurich, Zurich Switzerland; and
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Boyle CN, Lutz TA. Amylinergic control of food intake in lean and obese rodents. Physiol Behav 2011; 105:129-37. [DOI: 10.1016/j.physbeh.2011.02.015] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2010] [Revised: 02/04/2011] [Accepted: 02/08/2011] [Indexed: 10/18/2022]
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Baraboi ED, St-Pierre DH, Shooner J, Timofeeva E, Richard D. Brain activation following peripheral administration of the GLP-1 receptor agonist exendin-4. Am J Physiol Regul Integr Comp Physiol 2011; 301:R1011-24. [DOI: 10.1152/ajpregu.00424.2010] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
The aim of our study was to investigate the anorectic and brain stimulatory effects of various doses of exendin-4 (Ex-4) and to investigate the role of the vagus nerve in Ex-4-induced brain activation. A dose-related increase in c- fos mRNA expression was observed following Ex-4 administration (0.155–15.5 μg/kg). Doses of Ex-4 that caused anorexia without aversive effects (0.155, 0.775 μg/kg) induced c- fos expression in the hypothalamic arcuate and paraventricular (PVH; parvocellular) nuclei as well as in the limbic and brainstem structures. Doses of Ex-4 that caused aversion (1.55, 15.5 μg/kg) stimulated the same regions (in a more intense way) and additionally activated the magnocellular hypothalamic structures (supraoptic nucleus and PVH magnocellular). The brain c- fos pattern induced by Ex-4 showed both similarities and differences with that induced by refeeding. Subdiaphragmatic vagotomy significantly blunted the stimulation of c- fos mRNA expression induced by Ex-4 in the nodose ganglion, the medial part of nucleus of the solitary tract, and the parvocellular division of the PVH. Pretreatment with Ex-9-39 (330 μg/kg ip) impaired the neuronal activation evoked by Ex-4 in all brain regions and in the nodose ganglion. Effects of Ex-4 on hypothalamic-pituitary-adrenal axis activity were not altered by vagotomy. Results of this study demonstrate and relate the anorectic and brain stimulatory effects of aversive and nonaversive doses of Ex-4 and indicate that the activation of specific central regions induced by the peripheral administration of Ex-4 is, at least in part, dependent on the integrity of the vagus nerve.
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Affiliation(s)
- Elena-Dana Baraboi
- Merck-Frosst/Canadian Institutes of Health Research Chair in Obesity and Institut Universitaire de Cardiologie et de Pneumologie de Québec, Québec, Canada
| | - David H. St-Pierre
- Merck-Frosst/Canadian Institutes of Health Research Chair in Obesity and Institut Universitaire de Cardiologie et de Pneumologie de Québec, Québec, Canada
| | - Julie Shooner
- Merck-Frosst/Canadian Institutes of Health Research Chair in Obesity and Institut Universitaire de Cardiologie et de Pneumologie de Québec, Québec, Canada
| | - Elena Timofeeva
- Merck-Frosst/Canadian Institutes of Health Research Chair in Obesity and Institut Universitaire de Cardiologie et de Pneumologie de Québec, Québec, Canada
| | - Denis Richard
- Merck-Frosst/Canadian Institutes of Health Research Chair in Obesity and Institut Universitaire de Cardiologie et de Pneumologie de Québec, Québec, Canada
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Punjabi M, Arnold M, Geary N, Langhans W, Pacheco-López G. Peripheral glucagon-like peptide-1 (GLP-1) and satiation. Physiol Behav 2011; 105:71-6. [PMID: 21371486 DOI: 10.1016/j.physbeh.2011.02.038] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2011] [Accepted: 02/23/2011] [Indexed: 01/23/2023]
Abstract
Peripheral GLP-1 is produced by post-translational processing of pro-glucagon in enteroendocrine L-cells and is released in response to luminal nutrient (primarily carbohydrate and fat) stimulation. GLP-1 is well known for its potent insulinotropic and gluco-regulatory effects. GLP-1 receptors (GLP-1R) are expressed in the periphery and in several brain areas that are implicated in the control of eating. Both central and peripheral administration of GLP-1 have been shown to reduce food intake. Unresolved, however, is whether these effects reflect functions of endogenous GLP-1. Data collected in our laboratory indicate that in chow-fed rats: 1) Remotely controlled, intra-meal intravenous (IV) or intraperitoneal (IP) GLP-1 infusions selectively reduce meal size; 2) hindbrain GLP-1R activation is involved in the eating-inhibitory effect of IV infused GLP-1, whereas intact abdominal vagal afferents are necessary for the eating-inhibitory effect of IP, but not IV, infused GLP-1; 3) GLP-1 degradation in the liver prevents a systemic increase in endogenous GLP-1 during normal chow meals in rats; and 4) peripheral or hindbrain GLP-1R antagonism by exendin-9 does not affect spontaneous eating. Also, although our data indicate that peripheral GLP-1 can act in two different sites to inhibit eating, they argue against a role of systemic increases in endogenous GLP-1 in satiation in chow-fed rats. Therefore, further studies should examine whether a local paracrine action of GLP-1 in the intestine or and endocrine action in the hepatic-portal area is physiologically relevant for satiation.
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Affiliation(s)
- Mukesh Punjabi
- Physiology and Behaviour Laboratory, Institute of Food, Nutrition and Health, ETH Zurich, 8603 Schwerzenbach, Switzerland
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Oliveira-Maia AJ, Roberts CD, Simon SA, Nicolelis MAL. Gustatory and reward brain circuits in the control of food intake. Adv Tech Stand Neurosurg 2011; 36:31-59. [PMID: 21197607 DOI: 10.1007/978-3-7091-0179-7_3] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Gustation is a multisensory process allowing for the selection of nutrients and the rejection of irritating and/or toxic compounds. Since obesity is a highly prevalent condition that is critically dependent on food intake and energy expenditure, a deeper understanding of gustatory processing is an important objective in biomedical research. Recent findings have provided evidence that central gustatory processes are distributed across several cortical and subcortical brain areas. Furthermore, these gustatory sensory circuits are closely related to the circuits that process reward. Here, we present an overview of the activation and connectivity between central gustatory and reward areas. Moreover, and given the limitations in number and effectiveness of treatments currently available for overweight patients, we discuss the possibility of modulating neuronal activity in these circuits as an alternative in the treatment of obesity.
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Affiliation(s)
- A J Oliveira-Maia
- Department of Neurobiology, Duke University Medical Center, Durham, NC, USA,
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Potes CS, Turek VF, Cole RL, Vu C, Roland BL, Roth JD, Riediger T, Lutz TA. Noradrenergic neurons of the area postrema mediate amylin's hypophagic action. Am J Physiol Regul Integr Comp Physiol 2010; 299:R623-31. [DOI: 10.1152/ajpregu.00791.2009] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Circulating amylin inhibits food intake via activation of the area postrema (AP). The aim of this study was to identify the neurochemical phenotype of the neurons mediating amylin's hypophagic action by immunohistochemical and feeding studies in rats. Expression of c-Fos protein was used as a marker for neuronal activation and dopamine-β-hydroxylase (DBH), the enzyme-catalyzing noradrenaline synthesis, as a marker for noradrenergic neurons. We found that ∼50% of amylin-activated AP neurons are noradrenergic. To clarify the functional role of these neurons in amylin's effect on eating, noradrenaline-containing neurons in the AP were lesioned using a saporin conjugated to an antibody against DBH. Amylin (5 or 20 μg/kg sc)-induced anorexia was observed in sham-lesioned rats with both amylin doses. Rats with a lesion of > 50% of the noradrenaline neurons were unresponsive to the low dose of amylin (5 μg/kg) and only displayed a reduction in food intake 60 min after injection of the high amylin dose (20 μg/kg). In a terminal experiment, the same rats received amylin (20 μg/kg) or saline. The AP and nucleus of the solitary tract (NTS) were stained for DBH to assess noradrenaline lesion success and for c-Fos expression to evaluate amylin-induced neuronal activation. In contrast to sham-lesioned animals, noradrenaline-lesioned rats did not show a significant increase in amylin-induced c-Fos expression in the AP and NTS. We conclude that the noradrenergic neurons in the AP mediate at least part of amylin's hypophagic effect.
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Affiliation(s)
- Catarina S. Potes
- Institute of Veterinary Physiology and Zurich Center for Integrative Human Physiology, University of Zurich, Zurich, Switzerland; and
| | | | | | - Calvin Vu
- Amylin Pharmaceuticals, Inc., San Diego, California
| | | | | | - Thomas Riediger
- Institute of Veterinary Physiology and Zurich Center for Integrative Human Physiology, University of Zurich, Zurich, Switzerland; and
| | - Thomas A. Lutz
- Institute of Veterinary Physiology and Zurich Center for Integrative Human Physiology, University of Zurich, Zurich, Switzerland; and
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Abstract
Our knowledge of the complex mechanisms underlying energy homeostasis has expanded enormously in recent years. Food intake and body weight are tightly regulated by the hypothalamus, brainstem and reward circuits, on the basis both of cognitive inputs and of diverse humoral and neuronal signals of nutritional status. Several gut hormones, including cholecystokinin, glucagon-like peptide-1, peptide YY, oxyntomodulin, amylin, pancreatic polypeptide and ghrelin, have been shown to play an important role in regulating short-term food intake. These hormones therefore represent potential targets in the development of novel anti-obesity drugs. This review focuses on the role of gut hormones in short- and long-term regulation of food intake, and on the current state of development of gut hormone-based obesity therapies.
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Affiliation(s)
- Benjamin C T Field
- Department of Investigative Medicine, Imperial College London, Hammersmith Hospital Campus, London, UK
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50
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Bello NT, Kemm MH, Ofeldt EM, Moran TH. Dose combinations of exendin-4 and salmon calcitonin produce additive and synergistic reductions in food intake in nonhuman primates. Am J Physiol Regul Integr Comp Physiol 2010; 299:R945-52. [PMID: 20554932 DOI: 10.1152/ajpregu.00275.2010] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Glucagon-like peptide-1 (GLP-1) and amylin mediate the feedback control of eating by seemingly separate, but overlapping mechanisms. This study examined the effects of combined doses of the GLP-1 agonist, exendin-4 (Ex-4), and the amylin analog, salmon calcitonin (sCT), on food intake and meal patterns in adult male rhesus monkeys. Monkeys received intramuscular injections of Ex-4 (0, 0.1, 0.32, or 0.56 microg/kg), sCT (0, 0.1, or 0.32 microg/kg), or combinations thereof before a 6-h daily access to food. Dose combinations produced reductions in food intake that were significantly greater than those produced by the individual doses. Surface plots of the hourly intake indicated a synergistic interaction at lower doses of Ex-4 and sCT during the first 4 h of feeding and additive effects at hours 5 and 6. Meal pattern analysis revealed the combinational doses reduced average meal size and meal frequency by additive interactions, whereas infra-additive effects were apparent at lower doses for first meal size. Combinational doses were further characterized by administration of repeated daily injections of 0.56 microg/kg Ex-4 + 0.32 microg/kg sCT for 5 days. This resulted in sustained reductions in daily food intake (>70% from saline baseline) for 5 days with residual reductions ( approximately 48% from saline baseline) persisting on day 1 following the injections. In contrast, when pair-fed an identical amount of daily food, there was a compensatory food intake increase on day 1 following the pair-feeding ( approximately 132% of saline baseline). Such data suggest Ex-4 and sCT interact in an overall additive fashion to reduce food intake and further the understanding of how GLP-1 and amylin agonist combinations influence feeding behavior.
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Affiliation(s)
- Nicholas T Bello
- Department of Psychiatry and Behavioral Sciences, Johns Hopkins Univ. School of Medicine, Baltimore, MD 21205, USA
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