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Abstract
Eating behaviours are determined by the integration of interoceptive and environmental inputs. During pregnancy, numerous physiological adaptations take place in the maternal organism to provide an adequate environment for embryonic growth. Among them, whole-body physiological remodelling directly influences eating patterns, commonly causing notable taste perception alterations, food aversions and cravings. Recurrent food cravings for and compulsive eating of highly palatable food can contribute to the development and maintenance of gestational overweight and obesity with potential adverse health consequences for the offspring. Although much is known about how maternal eating habits influence offspring health, the mechanisms that underlie changes in taste perception and food preference during pregnancy (which guide and promote feeding) are only just starting to be elucidated. Given the limited and diffuse understanding of the neurobiology of gestational eating patterns, the aim of this Review is to compile, integrate and discuss the research conducted on this topic in both experimental models and humans. This article sheds light on the mechanisms that drive changes in female feeding behaviours during distinct physiological states. Understanding these processes is crucial to improve gestational parent health and decrease the burden of metabolic and food-related diseases in future generations.
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Affiliation(s)
- Roberta Haddad-Tóvolli
- Neuronal Control of Metabolism (NeuCoMe) Laboratory, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Barcelona, Spain.
| | - Marc Claret
- Neuronal Control of Metabolism (NeuCoMe) Laboratory, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Barcelona, Spain.
- CIBER de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), Barcelona, Spain.
- School of Medicine, Universitat de Barcelona, Barcelona, Spain.
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2
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Geisler CE, Hayes MR. Metabolic hormone action in the VTA: Reward-directed behavior and mechanistic insights. Physiol Behav 2023; 268:114236. [PMID: 37178855 PMCID: PMC10330780 DOI: 10.1016/j.physbeh.2023.114236] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2023] [Revised: 04/10/2023] [Accepted: 05/10/2023] [Indexed: 05/15/2023]
Abstract
Dysfunctional signaling in midbrain reward circuits perpetuates diseases characterized by compulsive overconsumption of rewarding substances such as substance abuse, binge eating disorder, and obesity. Ventral tegmental area (VTA) dopaminergic activity serves as an index for how rewarding stimuli are perceived and triggers behaviors necessary to obtain future rewards. The evolutionary linking of reward with seeking and consuming palatable foods ensured an organism's survival, and hormone systems that regulate appetite concomitantly developed to regulate motivated behaviors. Today, these same mechanisms serve to regulate reward-directed behavior around food, drugs, alcohol, and social interactions. Understanding how hormonal regulation of VTA dopaminergic output alters motivated behaviors is essential to leveraging therapeutics that target these hormone systems to treat addiction and disordered eating. This review will outline our current understanding of the mechanisms underlying VTA action of the metabolic hormones ghrelin, glucagon-like peptide-1, amylin, leptin, and insulin to regulate behavior around food and drugs of abuse, highlighting commonalities and differences in how these five hormones ultimately modulate VTA dopamine signaling.
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Affiliation(s)
- Caroline E Geisler
- Department of Psychiatry, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA.
| | - Matthew R Hayes
- Department of Psychiatry, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
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3
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Russo C, Valle MS, Russo A, Malaguarnera L. The Interplay between Ghrelin and Microglia in Neuroinflammation: Implications for Obesity and Neurodegenerative Diseases. Int J Mol Sci 2022; 23:ijms232113432. [PMID: 36362220 PMCID: PMC9654207 DOI: 10.3390/ijms232113432] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2022] [Revised: 10/29/2022] [Accepted: 11/01/2022] [Indexed: 11/06/2022] Open
Abstract
Numerous studies have shown that microglia are capable of producing a wide range of chemokines to promote inflammatory processes within the central nervous system (CNS). These cells share many phenotypical and functional characteristics with macrophages, suggesting that microglia participate in innate immune responses in the brain. Neuroinflammation induces neurometabolic alterations and increases in energy consumption. Microglia may constitute an important therapeutic target in neuroinflammation. Recent research has attempted to clarify the role of Ghre signaling in microglia on the regulation of energy balance, obesity, neuroinflammation and the occurrence of neurodegenerative diseases. These studies strongly suggest that Ghre modulates microglia activity and thus affects the pathophysiology of neurodegenerative diseases. This review aims to summarize what is known from the current literature on the way in which Ghre modulates microglial activity during neuroinflammation and their impact on neurometabolic alterations in neurodegenerative diseases. Understanding the role of Ghre in microglial activation/inhibition regulation could provide promising strategies for downregulating neuroinflammation and consequently for diminishing negative neurological outcomes.
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Affiliation(s)
- Cristina Russo
- Section of Pathology, Department of Biomedical and Biotechnological Sciences, School of Medicine, University of Catania, 95123 Catania, Italy
| | - Maria Stella Valle
- Laboratory of Neuro-Biomechanics, Department of Biomedical and Biotechnological Sciences, School of Medicine, University of Catania, 95123 Catania, Italy
- Section of Physiology, Department of Biomedical and Biotechnological Sciences, University of Catania, 95123 Catania, Italy
| | - Antonella Russo
- Section of Physiology, Department of Biomedical and Biotechnological Sciences, University of Catania, 95123 Catania, Italy
| | - Lucia Malaguarnera
- Section of Pathology, Department of Biomedical and Biotechnological Sciences, School of Medicine, University of Catania, 95123 Catania, Italy
- Correspondence:
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4
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Wetzel L, Pourbaix M, Riegler A, Pfeifer AM, Reinhard I, Hoffmann S, Vollstädt-Klein S, Kiefer F, Sommer W, Bumb JM, Bach P, Koopmann A. G-CuP: the effect of a forced oral glucose intake on alcohol craving and mesolimbic cue reactivity in alcohol dependence-study protocol of a randomized, double-blind, placebo-controlled crossover study. Trials 2022; 23:693. [PMID: 35986409 PMCID: PMC9389768 DOI: 10.1186/s13063-022-06626-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2022] [Accepted: 08/03/2022] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Multiple studies indicate that a lower plasma level of the acetylated form of the appetite-regulating hormone ghrelin and higher plasma levels of insulin lead to a reduction in subjective alcohol craving and a reduced mesolimbic cue reactivity in functional magnetic resonance imaging (fMRI) when being exposed to alcohol-associated stimuli. The ghrelin level can physiologically be reduced by the induction of stomach distension and the ingestion of glucose or lipids. METHODS A total of 108 alcohol-dependent patients aged between 18 and 65 years are examined in the randomized, double-blind, placebo-controlled crossover study. After collecting demographic and psychometric data, participants take part in an alcohol exposure session. Afterwards, the participants go through the intervention condition (oral glucose intake) and the control condition (placebo intake) in a randomized order on two examination days. Blood samples are taken repeatedly (every 10 min) during the study course on both measuring days to determine changes in acetylated and total ghrelin and insulin plasma levels. In parallel, subjective alcohol craving after the glucose or placebo intake as the primary outcome is assessed using the Alcohol Urge Questionnaire (AUQ) and a visual analog scale (VAS). To examine the mesolimbic cue reactivity as the secondary outcome, a fMRI measurement is conducted while being exposed to alcohol-related stimuli. Appropriate statistical analysis will be used for the evaluation of the outcomes. DISCUSSION If successful, the results of this study could offer alcohol-dependent patients a new potential option for acute short-term reduction of alcohol craving and thus prevent relapses and prolong periods of abstinence in the long term. TRIAL REGISTRATION German Clinical Trials Register DRKS00022419 (UTN: U1111-1278-9428). Retrospectively registered on September 15, 2020.
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Affiliation(s)
- Lea Wetzel
- Medical Faculty Mannheim, Heidelberg University, Heidelberg, Germany.
- Department of Addictive Behavior and Addiction Medicine, Central Institute of Mental Health (CIMH), Medical Faculty Mannheim/ Heidelberg University, Mannheim, Germany.
| | - Madeleine Pourbaix
- Department of Addictive Behavior and Addiction Medicine, Central Institute of Mental Health (CIMH), Medical Faculty Mannheim/ Heidelberg University, Mannheim, Germany
| | - Alisa Riegler
- Department of Addictive Behavior and Addiction Medicine, Central Institute of Mental Health (CIMH), Medical Faculty Mannheim/ Heidelberg University, Mannheim, Germany
- Feuerlein Centre on Translational Addiction Medicine (FCTS), University of Heidelberg, Heidelberg, Germany
| | - Anna-Maria Pfeifer
- Department of Addictive Behavior and Addiction Medicine, Central Institute of Mental Health (CIMH), Medical Faculty Mannheim/ Heidelberg University, Mannheim, Germany
| | - Iris Reinhard
- Department of Biostatistics, Central Institute of Mental Health (CIMH), Medical Faculty Mannheim/Heidelberg University, Mannheim, Germany
| | - Sabine Hoffmann
- Department of Addictive Behavior and Addiction Medicine, Central Institute of Mental Health (CIMH), Medical Faculty Mannheim/ Heidelberg University, Mannheim, Germany
- Department of Biostatistics, Central Institute of Mental Health (CIMH), Medical Faculty Mannheim/Heidelberg University, Mannheim, Germany
| | - Sabine Vollstädt-Klein
- Department of Addictive Behavior and Addiction Medicine, Central Institute of Mental Health (CIMH), Medical Faculty Mannheim/ Heidelberg University, Mannheim, Germany
| | - Falk Kiefer
- Department of Addictive Behavior and Addiction Medicine, Central Institute of Mental Health (CIMH), Medical Faculty Mannheim/ Heidelberg University, Mannheim, Germany
- Feuerlein Centre on Translational Addiction Medicine (FCTS), University of Heidelberg, Heidelberg, Germany
| | - Wolfgang Sommer
- Institute of Psychopharmacology, Central Institute of Mental Health (CIMH), Medical Faculty Mannheim/Heidelberg University, Mannheim, Germany
| | - Jan Malte Bumb
- Department of Addictive Behavior and Addiction Medicine, Central Institute of Mental Health (CIMH), Medical Faculty Mannheim/ Heidelberg University, Mannheim, Germany
| | - Patrick Bach
- Department of Addictive Behavior and Addiction Medicine, Central Institute of Mental Health (CIMH), Medical Faculty Mannheim/ Heidelberg University, Mannheim, Germany
- Feuerlein Centre on Translational Addiction Medicine (FCTS), University of Heidelberg, Heidelberg, Germany
| | - Anne Koopmann
- Department of Addictive Behavior and Addiction Medicine, Central Institute of Mental Health (CIMH), Medical Faculty Mannheim/ Heidelberg University, Mannheim, Germany
- Feuerlein Centre on Translational Addiction Medicine (FCTS), University of Heidelberg, Heidelberg, Germany
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Hegab IM, Yao B, Qian Z, Tan Y, Pu Q, Wang Z, Wang H, Su J. Examining sex disparities in risk/reward trade-offs in Smith's zokors, Eospalax smithii. Behav Processes 2022; 201:104716. [PMID: 35901938 DOI: 10.1016/j.beproc.2022.104716] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2022] [Revised: 07/05/2022] [Accepted: 07/23/2022] [Indexed: 11/02/2022]
Abstract
Risk taking is imperative for the survival and fitness of animals since they are constantly facing innumerable threats from various sources. Indeed, the ability of the individual to balance the costs and benefits of various options and adopt a wise decision is critical for the animal well-being. We modified several traditionally used anxiety tests [The modified light-dark box (mLDB), the modified open field test (mOFT) and the modified defensive withdrawal apparatus (mDWA)] by adding a palatable food reward within the anxiogenic zone which granted us to assess the sex differences in risk-taking behavior in Smith's zokors (Eospalax smithii), a typical subterranean rodent species endemic to the Qinghai-Tibetan Plateau. Concomitant with our working hypothesis, female zokors showed strong aversion and avoidance behavioral responses when tested in the mOFT and mDWA while there were no apparent sexually dimorphic behavioral changes when they were tested in the mLDB (Except for the percentage of food consumed and the latency till start feeding). Furthermore, comparison between the three behavioral paradigms revealed that both sexes showed different behavioral responses toward the different behavioral tests. Sex differences in repeatable behaviors were more profound in females than males. This might reflect different degrees of risk perception and emotionality that may differ considerably between the different models of anxiety. Our results highlighted the functional significance of a trade-off between risk and incentives in natural environment that both male and female zokors differ in the processing of risk assessment in the presence of a food reward.
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Affiliation(s)
- Ibrahim M Hegab
- Department of Hygiene, Zoonoses and Animal Behaviour and Management, Faculty of Veterinary Medicine, Suez Canal University, Ismailia 41522, Egypt
| | - Baohui Yao
- College of Grassland Science, Key Laboratory of Grassland Ecosystem (Ministry of Education), Gansu Agricultural University, Lanzhou 730070, China; Gansu Agricultural University-Massey University Research Centre for Grassland Biodiversity, Gansu Agricultural University, Lanzhou 730070, China
| | - Zhang Qian
- College of Grassland Science, Key Laboratory of Grassland Ecosystem (Ministry of Education), Gansu Agricultural University, Lanzhou 730070, China; Gansu Agricultural University-Massey University Research Centre for Grassland Biodiversity, Gansu Agricultural University, Lanzhou 730070, China
| | - Yuchen Tan
- College of Grassland Science, Key Laboratory of Grassland Ecosystem (Ministry of Education), Gansu Agricultural University, Lanzhou 730070, China; Gansu Agricultural University-Massey University Research Centre for Grassland Biodiversity, Gansu Agricultural University, Lanzhou 730070, China
| | - Qiangsheng Pu
- College of Grassland Science, Key Laboratory of Grassland Ecosystem (Ministry of Education), Gansu Agricultural University, Lanzhou 730070, China; Gansu Agricultural University-Massey University Research Centre for Grassland Biodiversity, Gansu Agricultural University, Lanzhou 730070, China
| | - Zhicheng Wang
- College of Grassland Science, Key Laboratory of Grassland Ecosystem (Ministry of Education), Gansu Agricultural University, Lanzhou 730070, China; Gansu Agricultural University-Massey University Research Centre for Grassland Biodiversity, Gansu Agricultural University, Lanzhou 730070, China
| | - Haifang Wang
- College of Grassland Science, Key Laboratory of Grassland Ecosystem (Ministry of Education), Gansu Agricultural University, Lanzhou 730070, China; Gansu Agricultural University-Massey University Research Centre for Grassland Biodiversity, Gansu Agricultural University, Lanzhou 730070, China
| | - Junhu Su
- College of Grassland Science, Key Laboratory of Grassland Ecosystem (Ministry of Education), Gansu Agricultural University, Lanzhou 730070, China; Gansu Agricultural University-Massey University Research Centre for Grassland Biodiversity, Gansu Agricultural University, Lanzhou 730070, China.
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6
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Stopyra MA, Friederich HC, Mönning E, Lavandier N, Bendszus M, Herzog W, Simon JJ. The influence of homeostatic mechanisms on neural regulation of food craving in anorexia nervosa. Psychol Med 2021; 51:1011-1019. [PMID: 31931900 PMCID: PMC8161429 DOI: 10.1017/s0033291719003970] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/27/2019] [Revised: 09/30/2019] [Accepted: 12/11/2019] [Indexed: 11/07/2022]
Abstract
BACKGROUND Restrictive food intake in anorexia nervosa (AN) has been related to an overactive cognitive control network inhibiting intuitive motivational responses to food stimuli. However, the influence of short-term homeostatic signaling on the neural regulation of cue-induced food craving in AN is still unclear. METHODS Twenty-five women with AN and 25 matched normal-weight women were examined on two occasions after receiving either glucose or water directly into their stomach using a nasogastric tube. Participants were blinded to the type of infusion. An event-related functional magnetic resonance imaging paradigm was used to investigate the effect of intestinal glucose load on neural processing during either simple viewing or distraction from food stimuli. RESULTS Neural differences between patients with AN and normal-weight participants were found during the distraction from food stimuli, but not during the viewing condition. When compared to controls, patients with AN displayed increased activation during food distraction in the left parietal lobule/precuneus and fusiform gyrus after water infusion and decreased activation in ventromedial prefrontal and cingulate regions after intestinal glucose load. CONCLUSIONS Independent of the cephalic phase and the awareness of caloric intake, homeostatic influences trigger disorder-specific reactions in AN. Food distraction in patients with AN is associated with either excessive higher-order cognitive control during physiological hunger or decreased internally directed attention after intestinal glucose load. These findings suggest that food distraction plays an important role in the psychopathology of AN. This study was registered on clinicaltrials.gov with identifier: NCT03075371.
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Affiliation(s)
- Marion A. Stopyra
- Department of General Internal Medicine and Psychosomatics, University Hospital Heidelberg, Heidelberg, Germany
- Psychological Institute, Heidelberg University, Heidelberg, Germany
| | - Hans-Christoph Friederich
- Department of General Internal Medicine and Psychosomatics, University Hospital Heidelberg, Heidelberg, Germany
| | - Esther Mönning
- Department of General Internal Medicine and Psychosomatics, University Hospital Heidelberg, Heidelberg, Germany
| | - Nora Lavandier
- Department of General Internal Medicine and Psychosomatics, University Hospital Heidelberg, Heidelberg, Germany
- Department of Neuropediatrics, University Hospital Essen, Essen, Germany
| | - Martin Bendszus
- Department of Neuroradiology, University Hospital Heidelberg, Heidelberg, Germany
| | - Wolfgang Herzog
- Department of General Internal Medicine and Psychosomatics, University Hospital Heidelberg, Heidelberg, Germany
| | - Joe J. Simon
- Department of General Internal Medicine and Psychosomatics, University Hospital Heidelberg, Heidelberg, Germany
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7
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Abstract
Human biology has evolved to keep body fat within a range that supports survival. During the last 25 years, obesity biologists have uncovered key aspects of physiology that prevent fat mass from becoming too low. In contrast, the mechanisms that counteract excessive adipose expansion are largely unknown. Evidence dating back to the 1950s suggests the existence of a blood-borne molecule that defends against weight gain. In this article, we discuss the research supporting an "unidentified factor of overfeeding" and models that explain its role in body weight control. If it exists, revealing the identity of this factor could end a long-lasting enigma of energy balance regulation and facilitate a much-needed breakthrough in the pharmacological treatment of obesity.
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Affiliation(s)
- Jens Lund
- Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Camilla Lund
- Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Thomas Morville
- Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Christoffer Clemmensen
- Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
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8
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Mani BK, Castorena CM, Vianna CR, Lee CE, Metzger NP, Vijayaraghavan P, Osborne-Lawrence S, Elmquist JK, Zigman JM. Combined Loss of Ghrelin Receptor and Cannabinoid CB1 Receptor in Mice Decreases Survival but does not Additively Reduce Body Weight or Eating. Neuroscience 2019; 447:53-62. [PMID: 31520709 DOI: 10.1016/j.neuroscience.2019.09.005] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2019] [Revised: 08/28/2019] [Accepted: 09/02/2019] [Indexed: 01/08/2023]
Abstract
Ghrelin administration increases food intake, body weight (BW), adiposity, and blood glucose. In contrast, although mouse models lacking ghrelin or its receptor (Growth Hormone Secretagogue Receptor (GHSR)) exhibit life-threatening hypoglycemia in starvation-like states, they do not exhibit appreciable reductions in food intake, BW, adiposity, blood glucose, or survival when food availability is unrestricted. This suggests the existence of a parallel neuromodulatory system that can compensate for disruptions in the ghrelin system in certain settings. Here, we hypothesized that the cannabinoid CB1 receptor (CB1R) may encode this putative redundancy, and as such, that genetic deletion of both GHSR and CB1R would exaggerate the metabolic deficits associated with deletion of GHSR alone. To test this hypothesis, we assessed food intake, BW, blood glucose, survival, and plasma acyl-ghrelin in ad libitum-fed male wild-type mice and those that genetically lack GHSR (GHSR-nulls), CB1R (CB1R-nulls), or both GHSR and CB1R (double-nulls). BW, fat mass, and lean mass were similar in GHSR-nulls and wild-types, lower in CB1R-nulls, but not further reduced in double-nulls. Food intake, plasma acyl-ghrelin, and blood glucose were similar among genotypes. Deletion of either GHSR or CB1R alone did not have a statistically-significant effect on survival, but double-nulls demonstrated a statistical trend towards decreased survival (p = 0.07). We conclude that CB1R is not responsible for the normal BW, adiposity, food intake, and blood glucose observed in GHSR-null mice in the setting of unrestricted food availability. Nor is CB1R required for plasma acyl-ghrelin secretion in that setting. However, GHSR may be protective against exaggerated mortality associated with CB1R deletion.
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Affiliation(s)
- Bharath K Mani
- Center for Hypothalamic Research, Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Carlos M Castorena
- Center for Hypothalamic Research, Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Claudia R Vianna
- Center for Hypothalamic Research, Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Charlotte E Lee
- Center for Hypothalamic Research, Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Nathan P Metzger
- Center for Hypothalamic Research, Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Prasanna Vijayaraghavan
- Center for Hypothalamic Research, Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Sherri Osborne-Lawrence
- Center for Hypothalamic Research, Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Joel K Elmquist
- Center for Hypothalamic Research, Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX, USA; Division of Endocrinology & Metabolism, Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX, USA; Department of Psychiatry, University of Texas Southwestern Medical Center, Dallas, TX, USA; Department of Pharmacology, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Jeffrey M Zigman
- Center for Hypothalamic Research, Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX, USA; Division of Endocrinology & Metabolism, Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX, USA; Department of Psychiatry, University of Texas Southwestern Medical Center, Dallas, TX, USA.
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9
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Lockie SH, Stark R, Spanswick DC, Andrews ZB. Glucose availability regulates ghrelin-induced food intake in the ventral tegmental area. J Neuroendocrinol 2019; 31:e12696. [PMID: 30742723 DOI: 10.1111/jne.12696] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/19/2018] [Revised: 12/13/2018] [Accepted: 02/08/2019] [Indexed: 12/23/2022]
Abstract
Information about metabolic status arrives in the brain in the form of a complex milieu of circulating signalling factors, including glucose and fatty acids, ghrelin, leptin and insulin. The specific interactions between humoural factors, brain sites of action and how they influence behaviour are largely unknown. We have previously observed interactions between glucose availability and the actions of ghrelin mediated via the agouti-related peptide neurones of the hypothalamus. In the present study, we examine whether these effects generalise to another ghrelin-sensitive brain nucleus, the ventral tegmental area (VTA). We altered glucose availability by injecting mice with glucose or 2-deoxyglucose i.p. to induce hyperglycaemia and glucopenia, respectively. Thirty minutes later, we injected ghrelin in the VTA. Glucose administration suppressed intra-VTA ghrelin-induced feeding. Leptin, a longer-term signal of positive energy balance, did not affect intra-VTA ghrelin-induced feeding. 2-Deoxyglucose and ghrelin both increased food intake in their own right and, together, they additively increased feeding. These results add support to the idea that calculation of metabolic need depends on multiple signals across multiple brain regions and identifies that VTA circuits are sensitive to the integration of signals reflecting internal homeostatic state and influencing food intake.
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Affiliation(s)
- Sarah H Lockie
- Monash Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia
- Department of Physiology, Monash University, Clayton, Victoria, Australia
| | - Romana Stark
- Monash Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia
- Department of Physiology, Monash University, Clayton, Victoria, Australia
| | - David C Spanswick
- Monash Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia
- Department of Physiology, Monash University, Clayton, Victoria, Australia
| | - Zane B Andrews
- Monash Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia
- Department of Physiology, Monash University, Clayton, Victoria, Australia
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10
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Zhu B, Shi C, Park CG, Zhao X, Reutrakul S. Effects of sleep restriction on metabolism-related parameters in healthy adults: A comprehensive review and meta-analysis of randomized controlled trials. Sleep Med Rev 2019; 45:18-30. [DOI: 10.1016/j.smrv.2019.02.002] [Citation(s) in RCA: 46] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2018] [Revised: 01/26/2019] [Accepted: 02/04/2019] [Indexed: 12/19/2022]
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11
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Edwin Thanarajah S, Iglesias S, Kuzmanovic B, Rigoux L, Stephan KE, Brüning JC, Tittgemeyer M. Modulation of midbrain neurocircuitry by intranasal insulin. Neuroimage 2019; 194:120-127. [PMID: 30914385 DOI: 10.1016/j.neuroimage.2019.03.050] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2017] [Revised: 03/19/2019] [Accepted: 03/22/2019] [Indexed: 02/07/2023] Open
Abstract
Insulin modulates dopamine neuron activity in midbrain and affects processes underlying food intake behaviour, including impulsivity and reward processing. Here, we used intranasal administration and task-free functional MRI in humans to assess time- and dose-dependent effects of insulin on functional connectivity of the dopaminergic midbrain - and how these effects varied depending on systemic insulin sensitivity as measured by HOMA-IR. Specifically, we used a repeated-measures design with factors dose (placebo, 40 IU, 100 IU, 160 IU), time (7 time points during a 90 min post-intervention interval), and group (low vs. high HOMA-IR). A factorial analysis identified a three-way interaction (with whole-brain significance) with regard to functional connectivity between midbrain and the ventromedial prefrontal cortex. This interaction demonstrates that systemic insulin sensitivity modulates the temporal course and dose-dependent effects of intranasal insulin on midbrain functional connectivity. It suggests that altered insulin sensitivity may impact on dopaminergic projections of the midbrain and might underlie the dysregulation of reward-related and motivational behaviour in obesity and diabetes. Perhaps most importantly, the time courses of midbrain functional connectivity we present may provide useful guidance for the design of future human studies that utilize intranasal insulin administration.
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Affiliation(s)
- Sharmili Edwin Thanarajah
- Max-Planck-Institute for Metabolism Research, Cologne, Germany; Department of Neurology, University Hospital of Cologne, Cologne, Germany
| | - Sandra Iglesias
- Translational Neuromodeling Unit, Institute for Biomedical Engineering, University of Zurich and Swiss Federal Institute of Technology, Zurich, Switzerland
| | | | - Lionel Rigoux
- Max-Planck-Institute for Metabolism Research, Cologne, Germany
| | - Klaas E Stephan
- Max-Planck-Institute for Metabolism Research, Cologne, Germany; Translational Neuromodeling Unit, Institute for Biomedical Engineering, University of Zurich and Swiss Federal Institute of Technology, Zurich, Switzerland
| | - Jens C Brüning
- Max-Planck-Institute for Metabolism Research, Cologne, Germany; Center for Endocrinology, Diabetes and Preventive Medicine (CEDP), University Hospital of Cologne, Cologne, Germany
| | - Marc Tittgemeyer
- Max-Planck-Institute for Metabolism Research, Cologne, Germany; Modern Diet and Physiology Center, USA; Cologne Cluster of Excellence in Cellular Stress and Aging-Associated Disease (CECAD), Cologne, Germany.
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12
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Matthews GA, Tye KM. Neural mechanisms of social homeostasis. Ann N Y Acad Sci 2019; 1457:5-25. [PMID: 30875095 DOI: 10.1111/nyas.14016] [Citation(s) in RCA: 98] [Impact Index Per Article: 19.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2018] [Revised: 12/15/2018] [Accepted: 01/09/2019] [Indexed: 12/21/2022]
Abstract
Social connections are vital to survival throughout the animal kingdom and are dynamic across the life span. There are debilitating consequences of social isolation and loneliness, and social support is increasingly a primary consideration in health care, disease prevention, and recovery. Considering social connection as an "innate need," it is hypothesized that evolutionarily conserved neural systems underlie the maintenance of social connections: alerting the individual to their absence and coordinating effector mechanisms to restore social contact. This is reminiscent of a homeostatic system designed to maintain social connection. Here, we explore the identity of neural systems regulating "social homeostasis." We review findings from rodent studies evaluating the rapid response to social deficit (in the form of acute social isolation) and propose that parallel, overlapping circuits are engaged to adapt to the vulnerabilities of isolation and restore social connection. By considering the neural systems regulating other homeostatic needs, such as energy and fluid balance, we discuss the potential attributes of social homeostatic circuitry. We reason that uncovering the identity of these circuits/mechanisms will facilitate our understanding of how loneliness perpetuates long-term disease states, which we speculate may result from sustained recruitment of social homeostatic circuits.
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Affiliation(s)
- Gillian A Matthews
- Department of Brain and Cognitive Sciences, The Picower Institute for Learning and Memory, Massachusetts Institute of Technology, Cambridge, Massachusetts
| | - Kay M Tye
- Department of Brain and Cognitive Sciences, The Picower Institute for Learning and Memory, Massachusetts Institute of Technology, Cambridge, Massachusetts.,The Salk Institute for Biological Sciences, La Jolla, California
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13
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De Luca SN, Sominsky L, Soch A, Wang H, Ziko I, Rank MM, Spencer SJ. Conditional microglial depletion in rats leads to reversible anorexia and weight loss by disrupting gustatory circuitry. Brain Behav Immun 2019; 77:77-91. [PMID: 30578932 DOI: 10.1016/j.bbi.2018.12.008] [Citation(s) in RCA: 46] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/01/2018] [Revised: 12/04/2018] [Accepted: 12/12/2018] [Indexed: 01/12/2023] Open
Abstract
Microglia are highly sensitive to dietary influence, becoming activated acutely and long-term by high fat diet. However, their role in regulating satiety and feeding in healthy individuals remains unclear. Here we show that microglia are essential for the normal regulation of satiety and metabolism in rats. Short-term microglial depletion in a Cx3cr1-Dtr rat led to a dramatic weight loss that was largely accounted for by an acute reduction in food intake. This weight loss and anorexia were not likely due to a sickness response since the rats did not display peripheral or central inflammation, withdrawal, anxiety-like behavior, or nausea-associated pica. Hormonal and hypothalamic anatomical changes were largely compensatory to the suppressed food intake, which occurred in association with disruption of the gustatory circuitry at the paraventricular nucleus of the thalamus. Thus, microglia are important in supporting normal feeding behaviors and weight, and regulating preference for palatable food. Inhibiting this circuitry is able to over-ride strong compensatory drives to eat, providing a potential target for satiety control.
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Affiliation(s)
- Simone N De Luca
- School of Health and Biomedical Sciences, RMIT University, Melbourne, Vic. 3138, Australia
| | - Luba Sominsky
- School of Health and Biomedical Sciences, RMIT University, Melbourne, Vic. 3138, Australia
| | - Alita Soch
- School of Health and Biomedical Sciences, RMIT University, Melbourne, Vic. 3138, Australia
| | - Hao Wang
- School of Health and Biomedical Sciences, RMIT University, Melbourne, Vic. 3138, Australia
| | - Ilvana Ziko
- School of Health and Biomedical Sciences, RMIT University, Melbourne, Vic. 3138, Australia
| | - Michelle M Rank
- School of Health and Biomedical Sciences, RMIT University, Melbourne, Vic. 3138, Australia
| | - Sarah J Spencer
- School of Health and Biomedical Sciences, RMIT University, Melbourne, Vic. 3138, Australia.
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14
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Al Massadi O, Nogueiras R, Dieguez C, Girault JA. Ghrelin and food reward. Neuropharmacology 2019; 148:131-138. [PMID: 30615902 DOI: 10.1016/j.neuropharm.2019.01.001] [Citation(s) in RCA: 45] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2018] [Revised: 01/02/2019] [Accepted: 01/02/2019] [Indexed: 12/14/2022]
Abstract
Food intake is tightly regulated by homeostatic and reward mechanisms and the adequate function of both is necessary for the proper maintenance of energy balance. Ghrelin impacts on these two levels to induce feeding. In this review, we present the actions of ghrelin in food reward, including their dependence on other relevant modulators implicated in the motivational aspects of feeding, including dopamine, opioid peptides, and endocannabinoids. We also describe the interaction between brain areas involved in homeostatic regulation of feeding and the reward system, with a special emphasis on the role of arcuate nucleus melanocortins and lateral hypothalamus orexins in ghrelin function. Finally, we briefly discuss the actions of ghrelin in food reward in obesity. We propose that new insights into the mechanism of action of ghrelin in the rewarding and motivational control of food intake will help to understand food-related disorders including obesity and anorexia.
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Affiliation(s)
- Omar Al Massadi
- Inserm UMR-S 839, 75005, Paris, France; Sorbonne Université, Sciences and Engineering Faculty, 75005 Paris, France; Institut du Fer a Moulin, 75005, Paris, France.
| | - Ruben Nogueiras
- Department of Physiology, CIMUS, University of Santiago de Compostela-Instituto de Investigación Sanitaria, Santiago de Compostela, 15782, Spain; CIBER Fisiopatología de la Obesidad y Nutrición (CIBERobn), 15706, Spain
| | - Carlos Dieguez
- Department of Physiology, CIMUS, University of Santiago de Compostela-Instituto de Investigación Sanitaria, Santiago de Compostela, 15782, Spain; CIBER Fisiopatología de la Obesidad y Nutrición (CIBERobn), 15706, Spain
| | - Jean-Antoine Girault
- Inserm UMR-S 839, 75005, Paris, France; Sorbonne Université, Sciences and Engineering Faculty, 75005 Paris, France; Institut du Fer a Moulin, 75005, Paris, France
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15
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Maske CB, Loney GC, Lilly N, Terrill SJ, Williams DL. Intragastric nutrient infusion reduces motivation for food in male and female rats. Am J Physiol Endocrinol Metab 2018; 315. [PMID: 29533738 PMCID: PMC6087724 DOI: 10.1152/ajpendo.00308.2017] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
The idea that gut-derived satiation signals influence food reward has recently gained traction, but this hypothesis is largely based on studies focused on neural circuitry, not the peripherally released signals. Here, we directly tested the hypothesis that intragastric (IG) nutrient infusion can suppress motivation for food. In a series of experiments, IG sucrose infusion (15 kcal) significantly and reliably reduced operant responding for a sucrose reward on a progressive ratio (PR) schedule. Moreover, food deprivation for 24 h before the test session did not prevent the suppressive effect of nutrients. The suppressive effect of IG sucrose on fixed ratio 5 (FR5) operant responding was also assessed as a comparison. The effect of IG nutrients to reduce motivation was not limited to sucrose; IG Ensure infusion (9.3 kcal) also significantly reduced PR operant responding for sucrose pellets. To verify that these effects were not secondary to the osmotic challenge of concentrated nutrients, we tested IG infusion of noncaloric saline solutions equiosmolar to 40% sucrose or Ensure and found no effect. Finally, we focused on glucagon-like peptide-1 (GLP-1) and cholecystokinin (CCK) as candidate mediators for the effect of IG nutrients. Pretreatment with exendin-9, a GLP-1 receptor antagonist, delivered intraperitoneally, significantly attenuated the ability of IG nutrients to suppress PR responding and breakpoint in males, but not in females, whereas pretreatment with devazepide, a CCKA receptor antagonist, failed to do so in both sexes. Together, these data support the idea that nutrient-induced satiation signals influence food reward and may implicate GLP-1 in this process.
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Affiliation(s)
- Calyn B Maske
- Department of Psychology and Program in Neuroscience, Florida State University , Tallahassee, Florida
| | - Gregory C Loney
- Department of Psychology and Program in Neuroscience, Florida State University , Tallahassee, Florida
| | - Nicole Lilly
- Department of Psychology and Program in Neuroscience, Florida State University , Tallahassee, Florida
| | - Sarah J Terrill
- Department of Psychology and Program in Neuroscience, Florida State University , Tallahassee, Florida
| | - Diana L Williams
- Department of Psychology and Program in Neuroscience, Florida State University , Tallahassee, Florida
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16
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Reichenbach A, Stark R, Mequinion M, Lockie SH, Lemus MB, Mynatt RL, Luquet S, Andrews ZB. Carnitine acetyltransferase (Crat) in hunger-sensing AgRP neurons permits adaptation to calorie restriction. FASEB J 2018; 32:fj201800634R. [PMID: 29932868 PMCID: PMC6219829 DOI: 10.1096/fj.201800634r] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2018] [Accepted: 06/12/2018] [Indexed: 12/13/2022]
Abstract
Hunger-sensing agouti-related peptide (AgRP) neurons ensure survival by adapting metabolism and behavior to low caloric environments. This adaption is accomplished by consolidating food intake, suppressing energy expenditure, and maximizing fat storage (nutrient partitioning) for energy preservation. The intracellular mechanisms responsible are unknown. Here we report that AgRP carnitine acetyltransferase (Crat) knockout (KO) mice exhibited increased fatty acid utilization and greater fat loss after 9 d of calorie restriction (CR). No differences were seen in mice with ad libitum food intake. Eleven days ad libitum feeding after CR resulted in greater food intake, rebound weight gain, and adiposity in AgRP Crat KO mice compared with wild-type controls, as KO mice act to restore pre-CR fat mass. Collectively, this study highlights the importance of Crat in AgRP neurons to regulate nutrient partitioning and fat mass during chronically reduced caloric intake. The increased food intake, body weight gain, and adiposity in KO mice after CR also highlights the detrimental and persistent metabolic consequence of impaired substrate utilization associated with CR. This finding may have significant implications for postdieting weight management in patients with metabolic diseases.-Reichenbach, A., Stark, R., Mequinion, M., Lockie, S. H., Lemus, M. B., Mynatt, R. L., Luquet, S., Andrews, Z. B. Carnitine acetyltransferase (Crat) in hunger-sensing AgRP neurons permits adaptation to calorie restriction.
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Affiliation(s)
- Alex Reichenbach
- Monash Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia
- Department of Physiology, Monash University, Clayton, Victoria, Australia
| | - Romana Stark
- Monash Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia
- Department of Physiology, Monash University, Clayton, Victoria, Australia
| | - Mathieu Mequinion
- Monash Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia
- Department of Physiology, Monash University, Clayton, Victoria, Australia
| | - Sarah H. Lockie
- Monash Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia
- Department of Physiology, Monash University, Clayton, Victoria, Australia
| | - Moyra B. Lemus
- Monash Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia
- Department of Physiology, Monash University, Clayton, Victoria, Australia
| | - Randall L. Mynatt
- Gene Nutrient Interactions Laboratory, Pennington Biomedical Research Center, Louisiana State University System, Baton Rouge, Louisiana, USA
- Transgenic Core Facility, Pennington Biomedical Research Center, Louisiana State University System, Baton Rouge, Louisiana, USA; and
| | - Serge Luquet
- Université of Paris Diderot, Sorbonne Paris Cité, Unité de Biologie Fonctionelle et Adaptative, Centre National de la Recherche Scientifique (CNRS) Unité Mixte de Recherche 8251, Paris, France
| | - Zane B. Andrews
- Monash Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia
- Department of Physiology, Monash University, Clayton, Victoria, Australia
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17
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Reichenbach A, Mequinion M, Bayliss JA, Lockie SH, Lemus MB, Mynatt RL, Stark R, Andrews ZB. Carnitine Acetyltransferase in AgRP Neurons Is Required for the Homeostatic Adaptation to Restricted Feeding in Male Mice. Endocrinology 2018; 159:2473-2483. [PMID: 29697769 PMCID: PMC6692886 DOI: 10.1210/en.2018-00131] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/05/2018] [Accepted: 04/19/2018] [Indexed: 12/14/2022]
Abstract
Behavioral adaptation to periods of varying food availability is crucial for survival, and agouti-related protein (AgRP) neurons have been associated with entrainment to temporal restricted feeding. We have shown that carnitine acetyltransferase (Crat) in AgRP neurons enables metabolic flexibility and appropriate nutrient partitioning. In this study, by restricting food availability to 3 h/d during the light phase, we examined whether Crat is a component of a food-entrainable oscillator (FEO) that helps link behavior to food availability. AgRP Crat knockout (KO) mice consumed less food and regained less body weight but maintained blood glucose levels during the 25-day restricted feeding protocol. Importantly, we observed no difference in meal latency, food anticipatory activity (FAA), or brown adipose tissue temperature during the first 13 days of restricted feeding. However, as the restricted feeding paradigm progressed, we noticed an increased FAA in AgRP Crat KO mice. The delayed increase in FAA, which developed during the last 12 days of restricted feeding, corresponded with elevated plasma levels of corticosterone and nonesterified fatty acids, indicating it resulted from greater energy debt incurred by KO mice over the course of the experiment. These experiments highlight the importance of Crat in AgRP neurons in regulating feeding behavior and body weight gain during restricted feeding but not in synchronizing behavior to food availability. Thus, Crat within AgRP neurons forms a component of the homeostatic response to restricted feeding but is not likely to be a molecular component of FEO.
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Affiliation(s)
- Alex Reichenbach
- Monash Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia
- Department of Physiology, Monash University, Clayton, Victoria, Australia
| | - Mathieu Mequinion
- Monash Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia
- Department of Physiology, Monash University, Clayton, Victoria, Australia
| | - Jacqueline A Bayliss
- Monash Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia
- Department of Physiology, Monash University, Clayton, Victoria, Australia
| | - Sarah H Lockie
- Monash Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia
- Department of Physiology, Monash University, Clayton, Victoria, Australia
| | - Moyra B Lemus
- Monash Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia
- Department of Physiology, Monash University, Clayton, Victoria, Australia
| | - Randall L Mynatt
- Gene Nutrient Interactions Laboratory, Pennington Biomedical Research Center, Louisiana State University System, Baton Rouge, Louisiana
- Transgenic Core Facility, Pennington Biomedical Research Center, Louisiana State University System, Baton Rouge, Louisiana
| | - Romana Stark
- Monash Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia
- Department of Physiology, Monash University, Clayton, Victoria, Australia
| | - Zane B Andrews
- Monash Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia
- Department of Physiology, Monash University, Clayton, Victoria, Australia
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18
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Abstract
INTRODUCTION Anorexia nervosa (AN), bulimia nervosa (BN) and binge eating disorder (BED) are the primary eating disorders (EDs). The only psychopharmacological treatment options for EDs with approval in some countries include fluoxetine for BN and lisdexamfetamine for BED. Given the high comorbidity and genetic correlations with other psychiatric disorders, it seems possible that novel medications for these conditions might also be effective in EDs. Areas covered: The current scientific literature has increased our understanding of how medication could be beneficial for patients with EDs on a molecular, functional and behavioral level. On the basis of theoretical considerations about neurotransmitters, hormones and neural circuits, possible drug targets for the treatment of EDs may include signal molecules and receptors of the self-regulatory system such as serotonin, norepinephrine and glutamate, the hedonic system including opioids, cannabinoids and dopamine and the hypothalamic homeostatic system including histamine, ghrelin, leptin, insulin, and glucagon-like peptide-1. Expert commentary: The latest research points to an involvement of both the immune and the metabolic systems in the pathophysiology of EDs and highlights the importance of the microbiome. Therefore, the next few years may unveil drug targets for EDs not just inside and outside of the brain, but possibly even outside of the human body.
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Affiliation(s)
- Hubertus Himmerich
- a Department of Psychological Medicine , King's College London , London , UK
| | - Janet Treasure
- a Department of Psychological Medicine , King's College London , London , UK
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19
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Andermann ML, Lowell BB. Toward a Wiring Diagram Understanding of Appetite Control. Neuron 2017; 95:757-778. [PMID: 28817798 DOI: 10.1016/j.neuron.2017.06.014] [Citation(s) in RCA: 329] [Impact Index Per Article: 47.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2017] [Revised: 06/02/2017] [Accepted: 06/07/2017] [Indexed: 01/26/2023]
Abstract
Prior mouse genetic research has set the stage for a deep understanding of appetite regulation. This goal is now being realized through the use of recent technological advances, such as the ability to map connectivity between neurons, manipulate neural activity in real time, and measure neural activity during behavior. Indeed, major progress has been made with regard to meal-related gut control of appetite, arcuate nucleus-based hypothalamic circuits linking energy state to the motivational drive, hunger, and, finally, limbic and cognitive processes that bring about hunger-mediated increases in reward value and perception of food. Unexpected findings are also being made; for example, the rapid regulation of homeostatic neurons by cues that predict future food consumption. The aim of this review is to cover the major underpinnings of appetite regulation, describe recent advances resulting from new technologies, and synthesize these findings into an updated view of appetite regulation.
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Affiliation(s)
- Mark L Andermann
- Division of Endocrinology, Diabetes, and Metabolism, Department of Medicine, Beth Israel Deaconess Medical Center, Boston, MA 02215, USA; Program in Neuroscience, Harvard Medical School, Boston, MA 02115, USA.
| | - Bradford B Lowell
- Division of Endocrinology, Diabetes, and Metabolism, Department of Medicine, Beth Israel Deaconess Medical Center, Boston, MA 02215, USA; Program in Neuroscience, Harvard Medical School, Boston, MA 02115, USA.
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20
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Alcohol-seeking and relapse: A focus on incentive salience and contextual conditioning. Behav Processes 2017; 141:26-32. [DOI: 10.1016/j.beproc.2017.04.019] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2017] [Revised: 04/27/2017] [Accepted: 04/28/2017] [Indexed: 01/05/2023]
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21
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Stievenard A, Méquinion M, Andrews ZB, Destée A, Chartier-Harlin MC, Viltart O, Vanbesien-Mailliot CC. Is there a role for ghrelin in central dopaminergic systems? Focus on nigrostriatal and mesocorticolimbic pathways. Neurosci Biobehav Rev 2017; 73:255-275. [DOI: 10.1016/j.neubiorev.2016.11.021] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2016] [Revised: 11/23/2016] [Accepted: 11/25/2016] [Indexed: 12/21/2022]
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22
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Lockie SH, McAuley CV, Rawlinson S, Guiney N, Andrews ZB. Food Seeking in a Risky Environment: A Method for Evaluating Risk and Reward Value in Food Seeking and Consumption in Mice. Front Neurosci 2017; 11:24. [PMID: 28194094 PMCID: PMC5276994 DOI: 10.3389/fnins.2017.00024] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2016] [Accepted: 01/12/2017] [Indexed: 11/13/2022] Open
Abstract
Most studies that measure food intake in mice do so in the home cage environment. This necessarily means that mice do not engage in food seeking before consumption, a behavior that is ubiquitous in free-living animals. We modified and validated several commonly used anxiety tests to include a palatable food reward within the anxiogenic zone. This allowed us to assess risk-taking behavior in food seeking in mice in response to different metabolic stimuli. We modified the open field test and the light/dark box by placing palatable peanut butter chips within a designated food zone inside the anxiogenic zone of each apparatus. We then assessed parameters of the interaction with the food reward. Fasted mice or mice treated with ghrelin showed increased consumption and increased time spent in the food zone immediately around the food reward compared to ad libitum fed mice or mice treated with saline. However, fasted mice treated with IP glucose before exposure to the behavioral arena showed reduced time in the food zone compared to fasted controls, indicating that acute metabolic signals can modify the assessment of safety in food seeking in a risky environment. The tests described in this study will be useful in assessing risk processing and incentive salience of food reward, which are intrinsic components of food acquisition outside of the laboratory environment, in a range of genetic and pharmacological models.
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Affiliation(s)
- Sarah H Lockie
- Monash Biomedicine Discovery Institute and Department of Physiology, Monash University Clayton, VIC, Australia
| | - Clare V McAuley
- Monash Biomedicine Discovery Institute and Department of Physiology, Monash University Clayton, VIC, Australia
| | - Sasha Rawlinson
- Monash Biomedicine Discovery Institute and Department of Physiology, Monash University Clayton, VIC, Australia
| | - Natalie Guiney
- Monash Biomedicine Discovery Institute and Department of Physiology, Monash University Clayton, VIC, Australia
| | - Zane B Andrews
- Monash Biomedicine Discovery Institute and Department of Physiology, Monash University Clayton, VIC, Australia
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23
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Bojanowska E, Ciosek J. Can We Selectively Reduce Appetite for Energy-Dense Foods? An Overview of Pharmacological Strategies for Modification of Food Preference Behavior. Curr Neuropharmacol 2016; 14:118-42. [PMID: 26549651 PMCID: PMC4825944 DOI: 10.2174/1570159x14666151109103147] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2015] [Revised: 09/19/2015] [Accepted: 10/31/2015] [Indexed: 12/11/2022] Open
Abstract
Excessive intake of food, especially palatable and energy-dense carbohydrates and fats, is
largely responsible for the growing incidence of obesity worldwide. Although there are a number of
candidate antiobesity drugs, only a few of them have been proven able to inhibit appetite for palatable
foods without the concurrent reduction in regular food consumption. In this review, we discuss the
interrelationships between homeostatic and hedonic food intake control mechanisms in promoting
overeating with palatable foods and assess the potential usefulness of systemically administered pharmaceuticals that
impinge on the endogenous cannabinoid, opioid, aminergic, cholinergic, and peptidergic systems in the modification of
food preference behavior. Also, certain dietary supplements with the potency to reduce specifically palatable food intake
are presented. Based on human and animal studies, we indicate the most promising therapies and agents that influence the
effectiveness of appetite-modifying drugs. It should be stressed, however, that most of the data included in our review
come from preclinical studies; therefore, further investigations aimed at confirming the effectiveness and safety of the
aforementioned medications in the treatment of obese humans are necessary.
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Affiliation(s)
- Ewa Bojanowska
- Department of Behavioral Pathophysiology, Institute of General and Experimental Pathology, Medical University of Lodz, 60 Narutowicza Street, 90-136 Lodz, Poland.
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24
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Chen Y, Lin YC, Zimmerman CA, Essner RA, Knight ZA. Hunger neurons drive feeding through a sustained, positive reinforcement signal. eLife 2016; 5. [PMID: 27554486 PMCID: PMC5016090 DOI: 10.7554/elife.18640] [Citation(s) in RCA: 123] [Impact Index Per Article: 15.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2016] [Accepted: 08/23/2016] [Indexed: 01/22/2023] Open
Abstract
The neural mechanisms underlying hunger are poorly understood. AgRP neurons are activated by energy deficit and promote voracious food consumption, suggesting these cells may supply the fundamental hunger drive that motivates feeding. However recent in vivo recording experiments revealed that AgRP neurons are inhibited within seconds by the sensory detection of food, raising the question of how these cells can promote feeding at all. Here we resolve this paradox by showing that brief optogenetic stimulation of AgRP neurons before food availability promotes intense appetitive and consummatory behaviors that persist for tens of minutes in the absence of continued AgRP neuron activation. We show that these sustained behavioral responses are mediated by a long-lasting potentiation of the rewarding properties of food and that AgRP neuron activity is positively reinforcing. These findings reveal that hunger neurons drive feeding by transmitting a positive valence signal that triggers a stable transition between behavioral states. DOI:http://dx.doi.org/10.7554/eLife.18640.001
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Affiliation(s)
- Yiming Chen
- Department of Physiology, University of California, San Francisco, San Francisco, United States.,Kavli Institute for Fundamental Neuroscience, University of California, San Francisco, San Francisco, United States.,Neuroscience Graduate Program, University of California, San Francisco, San Francisco, United states
| | - Yen-Chu Lin
- Department of Physiology, University of California, San Francisco, San Francisco, United States.,Kavli Institute for Fundamental Neuroscience, University of California, San Francisco, San Francisco, United States
| | - Christopher A Zimmerman
- Department of Physiology, University of California, San Francisco, San Francisco, United States.,Kavli Institute for Fundamental Neuroscience, University of California, San Francisco, San Francisco, United States.,Neuroscience Graduate Program, University of California, San Francisco, San Francisco, United states
| | - Rachel A Essner
- Department of Physiology, University of California, San Francisco, San Francisco, United States.,Kavli Institute for Fundamental Neuroscience, University of California, San Francisco, San Francisco, United States
| | - Zachary A Knight
- Department of Physiology, University of California, San Francisco, San Francisco, United States.,Kavli Institute for Fundamental Neuroscience, University of California, San Francisco, San Francisco, United States.,Neuroscience Graduate Program, University of California, San Francisco, San Francisco, United states
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25
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Soch A, Bradburn S, Sominsky L, De Luca SN, Murgatroyd C, Spencer SJ. Effects of exercise on adolescent and adult hypothalamic and hippocampal neuroinflammation. Hippocampus 2016; 26:1435-1446. [PMID: 27438996 DOI: 10.1002/hipo.22620] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/11/2016] [Indexed: 01/05/2023]
Abstract
Adolescence is a period of significant brain plasticity that can be affected by environmental factors, including the degree of physical activity. Here we hypothesized that adolescent rats would be more sensitive to the beneficial metabolic and anti-inflammatory effects of voluntary exercise than adult rats, whose more mature brains have less capacity for plasticity. We tested this by giving adolescent and adult Wistar rats four weeks' voluntary access to running wheels. At the end of this period we assessed metabolic effects, including weight and circulating leptin and ghrelin, as well as performance in a novel object recognition test of memory and central changes in neuronal proliferation, survival, synaptic density, and inflammatory markers in hippocampus. We found exercise reduced fat mass and circulating leptin levels in both adults and adolescents but suppressed total weight gain and lean mass in adults only. Exercise stimulated neuronal proliferation in the suprapyramidal blade of the dentate gyrus in both adults and adolescents without altering the number of mature neurons during this time frame. Exercise also increased dentate microglial numbers in adolescents alone and microglial numbers in this region were inversely correlated with performance in the novel object recognition test. Together these data suggest that adolescent hippocampal microglia are more sensitive to the effects of exercise than those of adults, but this leads to no apparent improvement in recognition memory. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Alita Soch
- School of Health and Biomedical Sciences, RMIT University, Melbourne, Vic, Australia
| | - Steven Bradburn
- Centre for Healthcare Science Research, School of Healthcare Science, Manchester Metropolitan University, Manchester, United Kingdom
| | - Luba Sominsky
- School of Health and Biomedical Sciences, RMIT University, Melbourne, Vic, Australia
| | - Simone N De Luca
- School of Health and Biomedical Sciences, RMIT University, Melbourne, Vic, Australia
| | - Christopher Murgatroyd
- Centre for Healthcare Science Research, School of Healthcare Science, Manchester Metropolitan University, Manchester, United Kingdom
| | - Sarah J Spencer
- School of Health and Biomedical Sciences, RMIT University, Melbourne, Vic, Australia.
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Stark R, Reichenbach A, Andrews ZB. Hypothalamic carnitine metabolism integrates nutrient and hormonal feedback to regulate energy homeostasis. Mol Cell Endocrinol 2015; 418 Pt 1:9-16. [PMID: 26261054 DOI: 10.1016/j.mce.2015.08.002] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/23/2015] [Revised: 07/31/2015] [Accepted: 08/03/2015] [Indexed: 01/11/2023]
Abstract
The maintenance of energy homeostasis requires the hypothalamic integration of nutrient feedback cues, such as glucose, fatty acids, amino acids, and metabolic hormones such as insulin, leptin and ghrelin. Although hypothalamic neurons are critical to maintain energy homeostasis research efforts have focused on feedback mechanisms in isolation, such as glucose alone, fatty acids alone or single hormones. However this seems rather too simplistic considering the range of nutrient and endocrine changes associated with different metabolic states, such as starvation (negative energy balance) or diet-induced obesity (positive energy balance). In order to understand how neurons integrate multiple nutrient or hormonal signals, we need to identify and examine potential intracellular convergence points or common molecular targets that have the ability to sense glucose, fatty acids, amino acids and hormones. In this review, we focus on the role of carnitine metabolism in neurons regulating energy homeostasis. Hypothalamic carnitine metabolism represents a novel means for neurons to facilitate and control both nutrient and hormonal feedback. In terms of nutrient regulation, carnitine metabolism regulates hypothalamic fatty acid sensing through the actions of CPT1 and has an underappreciated role in glucose sensing since carnitine metabolism also buffers mitochondrial matrix levels of acetyl-CoA, an allosteric inhibitor of pyruvate dehydrogenase and hence glucose metabolism. Studies also show that hypothalamic CPT1 activity also controls hormonal feedback. We hypothesis that hypothalamic carnitine metabolism represents a key molecular target that can concurrently integrate nutrient and hormonal information, which is critical to maintain energy homeostasis. We also suggest this is relevant to broader neuroendocrine research as it predicts that hormonal signaling in the brain varies depending on current nutrient status. Indeed, the metabolic action of ghrelin, leptin or insulin at POMC or NPY neurons may depend on appropriate nutrient-sensing in these neurons and we hypothesize carnitine metabolism is critical in the integrative processing. Future research is required to examine the neuron-specific effects of carnitine metabolism on concurrent nutrient- and hormonal-sensing in AgRP and POMC neurons.
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Affiliation(s)
- Romana Stark
- Department of Physiology, Monash University, Clayton, Victoria 3183, Australia
| | - Alex Reichenbach
- Department of Physiology, Monash University, Clayton, Victoria 3183, Australia
| | - Zane B Andrews
- Department of Physiology, Monash University, Clayton, Victoria 3183, Australia.
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Diet-induced obesity causes ghrelin resistance in reward processing tasks. Psychoneuroendocrinology 2015; 62:114-20. [PMID: 26292268 DOI: 10.1016/j.psyneuen.2015.08.004] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/12/2015] [Revised: 08/07/2015] [Accepted: 08/07/2015] [Indexed: 11/21/2022]
Abstract
Diet-induced obesity (DIO) causes ghrelin resistance in hypothalamic Agouti-related peptide (AgRP) neurons. However, ghrelin promotes feeding through actions at both the hypothalamus and mesolimbic dopamine reward pathways. Therefore, we hypothesized that DIO would also establish ghrelin resistance in the ventral tegmental area (VTA), a major site of dopaminergic cell bodies important in reward processing. We observed reduced sucrose and saccharin consumption in Ghrelin KO vs Ghrelin WT mice. Moreover, DIO reduced saccharin consumption relative to chow-fed controls. These data suggest that the deletion of ghrelin and high fat diet both cause anhedonia. To assess if these are causally related, we tested whether DIO caused ghrelin resistance in a classic model of drug reward, conditioned place preference (CPP). Chow or high fat diet (HFD) mice were conditioned with ghrelin (1mg/kg in 10ml/kg ip) in the presence or absence of food in the conditioning chamber. We observed a CPP to ghrelin in chow-fed mice but not in HFD-fed mice. HFD-fed mice still showed a CPP for cocaine (20mg/kg), indicating that they maintained the ability to develop conditioned behaviour. The absence of food availability during ghrelin conditioning sessions induced a conditioned place aversion, an effect that was still present in both chow and HFD mice. Bilateral intra-VTA ghrelin injection (0.33μg/μl in 0.5μl) robustly increased feeding in both chow-fed and high fat diet (HFD)-fed mice; however, this was correlated with body weight only in the chow-fed mice. Our results suggest that DIO causes ghrelin resistance albeit not directly in the VTA. We suggest there is impaired ghrelin sensitivity in upstream pathways regulating reward pathways, highlighting a functional role for ghrelin linking appropriate metabolic sensing with reward processing.
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Maffei G, Santos-Pata D, Marcos E, Sánchez-Fibla M, Verschure PFMJ. An embodied biologically constrained model of foraging: from classical and operant conditioning to adaptive real-world behavior in DAC-X. Neural Netw 2015; 72:88-108. [PMID: 26585942 DOI: 10.1016/j.neunet.2015.10.004] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2015] [Revised: 10/08/2015] [Accepted: 10/08/2015] [Indexed: 01/08/2023]
Abstract
Animals successfully forage within new environments by learning, simulating and adapting to their surroundings. The functions behind such goal-oriented behavior can be decomposed into 5 top-level objectives: 'how', 'why', 'what', 'where', 'when' (H4W). The paradigms of classical and operant conditioning describe some of the behavioral aspects found in foraging. However, it remains unclear how the organization of their underlying neural principles account for these complex behaviors. We address this problem from the perspective of the Distributed Adaptive Control theory of mind and brain (DAC) that interprets these two paradigms as expressing properties of core functional subsystems of a layered architecture. In particular, we propose DAC-X, a novel cognitive architecture that unifies the theoretical principles of DAC with biologically constrained computational models of several areas of the mammalian brain. DAC-X supports complex foraging strategies through the progressive acquisition, retention and expression of task-dependent information and associated shaping of action, from exploration to goal-oriented deliberation. We benchmark DAC-X using a robot-based hoarding task including the main perceptual and cognitive aspects of animal foraging. We show that efficient goal-oriented behavior results from the interaction of parallel learning mechanisms accounting for motor adaptation, spatial encoding and decision-making. Together, our results suggest that the H4W problem can be solved by DAC-X building on the insights from the study of classical and operant conditioning. Finally, we discuss the advantages and limitations of the proposed biologically constrained and embodied approach towards the study of cognition and the relation of DAC-X to other cognitive architectures.
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Affiliation(s)
- Giovanni Maffei
- Laboratory of Synthetic, Perceptive, Emotive and Cognitive Systems (SPECS), Center of Autonomous Systems and Neurorobotics, Universitat Pompeu Fabra (UPF), Barcelona, Spain
| | - Diogo Santos-Pata
- Laboratory of Synthetic, Perceptive, Emotive and Cognitive Systems (SPECS), Center of Autonomous Systems and Neurorobotics, Universitat Pompeu Fabra (UPF), Barcelona, Spain
| | - Encarni Marcos
- Laboratory of Synthetic, Perceptive, Emotive and Cognitive Systems (SPECS), Center of Autonomous Systems and Neurorobotics, Universitat Pompeu Fabra (UPF), Barcelona, Spain
| | - Marti Sánchez-Fibla
- Laboratory of Synthetic, Perceptive, Emotive and Cognitive Systems (SPECS), Center of Autonomous Systems and Neurorobotics, Universitat Pompeu Fabra (UPF), Barcelona, Spain
| | - Paul F M J Verschure
- Laboratory of Synthetic, Perceptive, Emotive and Cognitive Systems (SPECS), Center of Autonomous Systems and Neurorobotics, Universitat Pompeu Fabra (UPF), Barcelona, Spain; Institució Catalana de Recerca i Estudis Avançats (ICREA), Barcelona, Spain.
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Denis RGP, Joly-Amado A, Webber E, Langlet F, Schaeffer M, Padilla SL, Cansell C, Dehouck B, Castel J, Delbès AS, Martinez S, Lacombe A, Rouch C, Kassis N, Fehrentz JA, Martinez J, Verdié P, Hnasko TS, Palmiter RD, Krashes MJ, Güler AD, Magnan C, Luquet S. Palatability Can Drive Feeding Independent of AgRP Neurons. Cell Metab 2015; 22:646-57. [PMID: 26278050 PMCID: PMC5024566 DOI: 10.1016/j.cmet.2015.07.011] [Citation(s) in RCA: 106] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/09/2014] [Revised: 06/03/2015] [Accepted: 07/17/2015] [Indexed: 01/20/2023]
Abstract
Feeding behavior is exquisitely regulated by homeostatic and hedonic neural substrates that integrate energy demand as well as the reinforcing and rewarding aspects of food. Understanding the net contribution of homeostatic and reward-driven feeding has become critical because of the ubiquitous source of energy-dense foods and the consequent obesity epidemic. Hypothalamic agouti-related peptide-secreting neurons (AgRP neurons) provide the primary orexigenic drive of homeostatic feeding. Using models of neuronal inhibition or ablation, we demonstrate that the feeding response to a fast ghrelin or serotonin receptor agonist relies on AgRP neurons. However, when palatable food is provided, AgRP neurons are dispensable for an appropriate feeding response. In addition, AgRP-ablated mice present exacerbated stress-induced anorexia and palatable food intake--a hallmark of comfort feeding. These results suggest that, when AgRP neuron activity is impaired, neural circuits sensitive to emotion and stress are engaged and modulated by food palatability and dopamine signaling.
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Affiliation(s)
- Raphaël G P Denis
- Unité de Biologie Fonctionnelle et Adaptative, Centre National la Recherche Scientifique, Unité Mixte de Recherche 8251, Université Paris Diderot, Sorbonne Paris Cité, 75205 Paris, France
| | - Aurélie Joly-Amado
- Unité de Biologie Fonctionnelle et Adaptative, Centre National la Recherche Scientifique, Unité Mixte de Recherche 8251, Université Paris Diderot, Sorbonne Paris Cité, 75205 Paris, France
| | - Emily Webber
- Diabetes, Endocrinology, and Obesity Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892-1453, USA; National Institute of Drug Abuse, Baltimore, MD 21224, USA
| | - Fanny Langlet
- Institut national de la santé et de la recherche médicale, Jean-Pierre Aubert Research Center, U837, 59000 Lille, France; Faculté de Médecine, Université droit et santé de Lille, 59000 Lille, France
| | - Marie Schaeffer
- Centre National la Recherche Scientifique, Unité Mixte de Recherche 5203, Institut de Génomique Fonctionnelle, 34000 Montpellier, France; Institut national de la santé et de la recherche médicale, U661, 34000 Montpellier, France; Unité Mixte de Recherche 5203, University of Montpellier, 34000 Montpellier, France
| | - Stéphanie L Padilla
- Howard Hughes Medical Institute, University of Washington, Seattle, WA 98195, USA; Department of Biochemistry, University of Washington, Seattle, WA 98195, USA
| | - Céline Cansell
- Unité de Biologie Fonctionnelle et Adaptative, Centre National la Recherche Scientifique, Unité Mixte de Recherche 8251, Université Paris Diderot, Sorbonne Paris Cité, 75205 Paris, France
| | - Bénédicte Dehouck
- Institut national de la santé et de la recherche médicale, Jean-Pierre Aubert Research Center, U837, 59000 Lille, France; Faculté de Médecine, Université droit et santé de Lille, 59000 Lille, France
| | - Julien Castel
- Unité de Biologie Fonctionnelle et Adaptative, Centre National la Recherche Scientifique, Unité Mixte de Recherche 8251, Université Paris Diderot, Sorbonne Paris Cité, 75205 Paris, France
| | - Anne-Sophie Delbès
- Unité de Biologie Fonctionnelle et Adaptative, Centre National la Recherche Scientifique, Unité Mixte de Recherche 8251, Université Paris Diderot, Sorbonne Paris Cité, 75205 Paris, France
| | - Sarah Martinez
- Unité de Biologie Fonctionnelle et Adaptative, Centre National la Recherche Scientifique, Unité Mixte de Recherche 8251, Université Paris Diderot, Sorbonne Paris Cité, 75205 Paris, France
| | - Amélie Lacombe
- Unité de Biologie Fonctionnelle et Adaptative, Centre National la Recherche Scientifique, Unité Mixte de Recherche 8251, Université Paris Diderot, Sorbonne Paris Cité, 75205 Paris, France
| | - Claude Rouch
- Unité de Biologie Fonctionnelle et Adaptative, Centre National la Recherche Scientifique, Unité Mixte de Recherche 8251, Université Paris Diderot, Sorbonne Paris Cité, 75205 Paris, France
| | - Nadim Kassis
- Unité de Biologie Fonctionnelle et Adaptative, Centre National la Recherche Scientifique, Unité Mixte de Recherche 8251, Université Paris Diderot, Sorbonne Paris Cité, 75205 Paris, France
| | - Jean-Alain Fehrentz
- Centre National la Recherche Scientifique, Institut des Biomolécules Max Mousseron, Unité Mixte de Recherche 5247, Ecole Nationale Supérieure de Chimie de Montpellier, Université Montpellier, 34093 Montpellier Cedex 5, France
| | - Jean Martinez
- Centre National la Recherche Scientifique, Institut des Biomolécules Max Mousseron, Unité Mixte de Recherche 5247, Ecole Nationale Supérieure de Chimie de Montpellier, Université Montpellier, 34093 Montpellier Cedex 5, France
| | - Pascal Verdié
- Centre National la Recherche Scientifique, Institut des Biomolécules Max Mousseron, Unité Mixte de Recherche 5247, Ecole Nationale Supérieure de Chimie de Montpellier, Université Montpellier, 34093 Montpellier Cedex 5, France
| | - Thomas S Hnasko
- Department of Neurosciences, University of California, San Diego, La Jolla, CA 92093, USA
| | - Richard D Palmiter
- Howard Hughes Medical Institute, University of Washington, Seattle, WA 98195, USA; Department of Biochemistry, University of Washington, Seattle, WA 98195, USA
| | - Michael J Krashes
- Diabetes, Endocrinology, and Obesity Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892-1453, USA; National Institute of Drug Abuse, Baltimore, MD 21224, USA
| | - Ali D Güler
- Howard Hughes Medical Institute, University of Washington, Seattle, WA 98195, USA; Department of Biochemistry, University of Washington, Seattle, WA 98195, USA; Department of Biology, University of Virginia, Charlottesville, VA 22904-4328, USA
| | - Christophe Magnan
- Unité de Biologie Fonctionnelle et Adaptative, Centre National la Recherche Scientifique, Unité Mixte de Recherche 8251, Université Paris Diderot, Sorbonne Paris Cité, 75205 Paris, France
| | - Serge Luquet
- Unité de Biologie Fonctionnelle et Adaptative, Centre National la Recherche Scientifique, Unité Mixte de Recherche 8251, Université Paris Diderot, Sorbonne Paris Cité, 75205 Paris, France.
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Trapp S, Cork SC. PPG neurons of the lower brain stem and their role in brain GLP-1 receptor activation. Am J Physiol Regul Integr Comp Physiol 2015; 309:R795-804. [PMID: 26290108 DOI: 10.1152/ajpregu.00333.2015] [Citation(s) in RCA: 56] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2015] [Accepted: 08/13/2015] [Indexed: 01/28/2023]
Abstract
Within the brain, glucagon-like peptide-1 (GLP-1) affects central autonomic neurons, including those controlling the cardiovascular system, thermogenesis, and energy balance. Additionally, GLP-1 influences the mesolimbic reward system to modulate the rewarding properties of palatable food. GLP-1 is produced in the gut and by hindbrain preproglucagon (PPG) neurons, located mainly in the nucleus tractus solitarii (NTS) and medullary intermediate reticular nucleus. Transgenic mice expressing glucagon promoter-driven yellow fluorescent protein revealed that PPG neurons not only project to central autonomic control regions and mesolimbic reward centers, but also strongly innervate spinal autonomic neurons. Therefore, these brain stem PPG neurons could directly modulate sympathetic outflow through their spinal inputs to sympathetic preganglionic neurons. Electrical recordings from PPG neurons in vitro have revealed that they receive synaptic inputs from vagal afferents entering via the solitary tract. Vagal afferents convey satiation to the brain from signals like postprandial gastric distention or activation of peripheral GLP-1 receptors. CCK and leptin, short- and long-term satiety peptides, respectively, increased the electrical activity of PPG neurons, while ghrelin, an orexigenic peptide, had no effect. These findings indicate that satiation is a main driver of PPG neuronal activation. They also show that PPG neurons are in a prime position to respond to both immediate and long-term indicators of energy and feeding status, enabling regulation of both energy balance and general autonomic homeostasis. This review discusses the question of whether PPG neurons, rather than gut-derived GLP-1, are providing the physiological substrate for the effects elicited by central nervous system GLP-1 receptor activation.
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Affiliation(s)
- Stefan Trapp
- Centre for Cardiovascular and Metabolic Neuroscience, Department of Neuroscience, Physiology and Pharmacology, University College London, London, United Kingdom
| | - Simon C Cork
- Centre for Cardiovascular and Metabolic Neuroscience, Department of Neuroscience, Physiology and Pharmacology, University College London, London, United Kingdom
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Ghrelin's Role in the Hypothalamic-Pituitary-Adrenal Axis Stress Response: Implications for Mood Disorders. Biol Psychiatry 2015; 78:19-27. [PMID: 25534754 DOI: 10.1016/j.biopsych.2014.10.021] [Citation(s) in RCA: 90] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/21/2014] [Revised: 09/26/2014] [Accepted: 10/15/2014] [Indexed: 12/24/2022]
Abstract
Ghrelin is a stomach hormone normally associated with feeding behavior and energy homeostasis. Recent studies highlight that ghrelin targets the brain to regulate a diverse number of functions, including learning, memory, motivation, stress responses, anxiety, and mood. In this review, we discuss recent animal and human studies showing that ghrelin regulates the hypothalamic-pituitary-adrenal axis and affects anxiety and mood disorders, such as depression and fear. We address the neural sites of action through which ghrelin regulates the hypothalamic-pituitary-adrenal axis and associated stress-induced behaviors, including the centrally projecting Edinger-Westphal nucleus, the hippocampus, amygdala, locus coeruleus, and the ventral tegmental area. Stressors modulate many behaviors associated with motivation, fear, anxiety, depression, and appetite; therefore, we assess the potential role for ghrelin as a stress feedback signal that regulates these associated behaviors. Finally, we briefly discuss important areas for future research that will help us move closer to potential ghrelin-based therapies to treat stress responses and related disorders.
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Srey CS, Maddux JMN, Chaudhri N. The attribution of incentive salience to Pavlovian alcohol cues: a shift from goal-tracking to sign-tracking. Front Behav Neurosci 2015; 9:54. [PMID: 25784867 PMCID: PMC4347508 DOI: 10.3389/fnbeh.2015.00054] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2014] [Accepted: 02/13/2015] [Indexed: 11/22/2022] Open
Abstract
Environmental stimuli that are reliably paired with alcohol may acquire incentive salience, a property that can operate in the use and abuse of alcohol. Here we investigated the incentive salience of Pavlovian alcohol cues using a preclinical animal model. Male, Long-Evans rats (Harlan) with unrestricted access to food and water were acclimated to drinking 15% ethanol (v/v) in their home-cages. Rats then received Pavlovian autoshaping training in which the 10 s presentation of a retractable lever served as the conditioned stimulus (CS) and 15% ethanol served as the unconditioned stimulus (US) (0.2 ml/CS; 12 CS presentations/session; 27 sessions). Next, in an operant test of conditioned reinforcement, nose pokes into an active aperture delivered presentations of the lever-CS, whereas nose pokes into an inactive aperture had no consequences. Across initial autoshaping sessions, goal-tracking behavior, as measured by entries into the fluid port where ethanol was delivered, developed rapidly. However, with extended training goal-tracking diminished, and sign-tracking responses, as measured by lever-CS activations, emerged. Control rats that received explicitly unpaired CS and US presentations did not show goal-tracking or sign-tracking responses. In the test for conditioned reinforcement, rats with CS-US pairings during autoshaping training made more active relative to inactive nose pokes, whereas rats in the unpaired control group did not. Moreover, active nose pokes were positively correlated with sign-tracking behavior during autoshaping. Extended training may produce a shift in the learned properties of Pavlovian alcohol cues, such that after initially predicting alcohol availability they acquire robust incentive salience.
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Affiliation(s)
- Chandra S Srey
- Department of Psychology, Center for Studies in Behavioral Neurobiology/FRQS Groupe de Recherche en Neurobiologie Comportementale, Concordia University Montreal, QC, Canada
| | - Jean-Marie N Maddux
- Department of Psychology, Center for Studies in Behavioral Neurobiology/FRQS Groupe de Recherche en Neurobiologie Comportementale, Concordia University Montreal, QC, Canada
| | - Nadia Chaudhri
- Department of Psychology, Center for Studies in Behavioral Neurobiology/FRQS Groupe de Recherche en Neurobiologie Comportementale, Concordia University Montreal, QC, Canada
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Wittekind DA, Kluge M. Ghrelin in psychiatric disorders - A review. Psychoneuroendocrinology 2015; 52:176-94. [PMID: 25459900 DOI: 10.1016/j.psyneuen.2014.11.013] [Citation(s) in RCA: 69] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/29/2014] [Revised: 11/13/2014] [Accepted: 11/13/2014] [Indexed: 12/21/2022]
Abstract
Ghrelin is a 28-amino-acid peptide hormone, first described in 1999 and broadly expressed in the organism. As the only known orexigenic hormone secreted in the periphery, it increases hunger and appetite, promoting food intake. Ghrelin has also been shown to be involved in various physiological processes being regulated in the central nervous system such as sleep, mood, memory and reward. Accordingly, it has been implicated in a series of psychiatric disorders, making it subject of increasing investigation, with knowledge rapidly accumulating. This review aims at providing a concise yet comprehensive overview of the role of ghrelin in psychiatric disorders. Ghrelin was consistently shown to exert neuroprotective and memory-enhancing effects and alleviated psychopathology in animal models of dementia. Few human studies show a disruption of the ghrelin system in dementia. It was also shown to play a crucial role in the pathophysiology of addictive disorders, promoting drug reward, enhancing drug seeking behavior and increasing craving in both animals and humans. Ghrelin's exact role in depression and anxiety is still being debated, as it was shown to both promote and alleviate depressive and anxiety-behavior in animal studies, with an overweight of evidence suggesting antidepressant effects. Not surprisingly, the ghrelin system is also implicated in eating disorders, however its exact role remains to be elucidated. Its widespread involvement has made the ghrelin system a promising target for future therapies, with encouraging findings in recent literature.
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Affiliation(s)
| | - Michael Kluge
- Department of Psychiatry and Psychotherapy, University of Leipzig, Leipzig, Germany
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Abstract
Heritability of obesity and body weight variation is high. Molecular genetic studies have led to the identification of mutations in a few genes, with a major effect on obesity (major genes and monogenic forms). Analyses of these genes have helped to unravel important pathways and have created a more profound understanding of body weight regulation. For most individuals, a polygenic basis is relevant for the genetic predisposition to obesity. Small effect sizes are conveyed by the polygenic variants. Hence, only if a number of these variants is harboured, a sizeable phenotypic effect is detectable. Most, if not all, of the genes relevant to weight regulation are expressed in the hypothalamus. This underscores the major role of this region of the brain in body weight regulation.
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Affiliation(s)
- Anke Hinney
- Department of Child and Adolescent Psychiatry, Psychosomatics and Psychotherapy, Universitätsklinikum Essen, Essen, Germany.
| | - Anna-Lena Volckmar
- Department of Child and Adolescent Psychiatry, Psychosomatics and Psychotherapy, Universitätsklinikum Essen, Essen, Germany.
| | - Jochen Antel
- Department of Child and Adolescent Psychiatry, Psychosomatics and Psychotherapy, Universitätsklinikum Essen, Essen, Germany.
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35
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Buss J, Havel PJ, Epel E, Lin J, Blackburn E, Daubenmier J. Associations of ghrelin with eating behaviors, stress, metabolic factors, and telomere length among overweight and obese women: preliminary evidence of attenuated ghrelin effects in obesity? Appetite 2014; 76:84-94. [PMID: 24462487 DOI: 10.1016/j.appet.2014.01.011] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2013] [Revised: 12/24/2013] [Accepted: 01/11/2014] [Indexed: 12/19/2022]
Abstract
Ghrelin regulates homeostatic food intake, hedonic eating, and is a mediator in the stress response. In addition, ghrelin has metabolic, cardiovascular, and anti-aging effects. This cross-sectional study examined associations between total plasma ghrelin, caloric intake based on 3day diet diaries, hedonic eating attitudes, stress-related and metabolic factors, and leukocyte telomere length in overweight (n=25) and obese women (n=22). We hypothesized associations between total plasma ghrelin and eating behaviors, stress, metabolic, cardiovascular, and cell aging factors among overweight women, but not among obese women due to lower circulating ghrelin levels and/or central resistance to ghrelin. Confirming previous studies demonstrating lowered plasma ghrelin in obesity, ghrelin levels were lower in the obese compared with overweight women. Among the overweight, ghrelin was positively correlated with caloric intake, giving in to cravings for highly palatable foods, and a flatter diurnal cortisol slope across 3days. These relationships were non-significant among the obese group. Among overweight women, ghrelin was negatively correlated with insulin resistance, systolic blood pressure, and heart rate, and positively correlated with telomere length. Among the obese subjects, plasma ghrelin concentrations were negatively correlated with insulin resistance, but were not significantly correlated with blood pressure, heart rate or telomere length. Total plasma ghrelin and its associations with food intake, hedonic eating, and stress are decreased in obesity, providing evidence consistent with the theory that central resistance to ghrelin develops in obesity and ghrelin's function in appetite regulation may have evolved to prevent starvation in food scarcity rather than cope with modern food excess. Furthermore, ghrelin is associated with metabolic and cardiovascular health, and may have anti-aging effects, but these effects may be attenuated in obesity.
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Affiliation(s)
- Julia Buss
- University of California, San Francisco, School of Nursing, United States
| | - Peter J Havel
- University of California, Davis, Department of Molecular Biosciences, School of Veterinary Medicine, United States; University of California, Davis, Department of Nutrition, United States
| | - Elissa Epel
- University of California, San Francisco, Department of Psychiatry, United States
| | - Jue Lin
- University of California, San Francisco, Department of Biochemistry and Biophysics, United States
| | - Elizabeth Blackburn
- University of California, San Francisco, Department of Biochemistry and Biophysics, United States
| | - Jennifer Daubenmier
- University of California, San Francisco, Osher Center for Integrative Medicine, Department of Medicine, United States.
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