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McGovern DJ, Phillips A, Ly A, Prévost ED, Ward L, Siletti K, Kim YS, Fenno LE, Ramakrishnan C, Deisseroth K, Ford CP, Root DH. Salience signaling and stimulus scaling of ventral tegmental area glutamate neuron subtypes. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.06.12.598688. [PMID: 38915564 PMCID: PMC11195246 DOI: 10.1101/2024.06.12.598688] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/26/2024]
Abstract
Ventral tegmental area (VTA) glutamatergic neurons participate in reward, aversion, drug-seeking, and stress. Subsets of VTA VGluT2+ neurons are capable of co-transmitting glutamate and GABA (VGluT2+VGaT+ neurons), transmitting glutamate without GABA (VGluT2+VGaT- neurons), or co-transmitting glutamate and dopamine (VGluT2+TH+ neurons), but whether these molecularly distinct subpopulations show behavior-related differences is not wholly understood. We identified that neuronal activity of each VGluT2+ subpopulation is sensitive to reward value but signaled this in different ways. The phasic maximum activity of VGluT2+VGaT+ neurons increased with sucrose concentration, whereas VGluT2+VGaT- neurons increased maximum and sustained activity with sucrose concentration, and VGluT2+TH+ neurons increased sustained but not maximum activity with sucrose concentration. Additionally, VGluT2+ subpopulations signaled consummatory preferences in different ways. VGluT2+VGaT- neurons and VGluT2+TH+ neurons showed a signaling preference for a behaviorally-preferred fat reward over sucrose, but in temporally-distinct ways. In contrast, VGluT2+VGaT+ neurons uniquely signaled a less behaviorally-preferred sucrose reward compared with fat. Further experiments suggested that VGluT2+VGaT+ consummatory reward-related activity was related to sweetness, partially modulated by hunger state, and not dependent on caloric content or behavioral preference. All VGluT2+ subtypes increased neuronal activity following aversive stimuli but VGluT2+VGaT+ neurons uniquely scaled their magnitude and sustained activity with footshock intensity. Optogenetic activation of VGluT2+VGaT+ neurons during low intensity footshock enhanced fear-related behavior without inducing place preference or aversion. We interpret these data such that VTA glutamatergic subpopulations signal different elements of rewarding and aversive experiences and highlight the unique role of VTA VGluT2+VGaT+ neurons in enhancing the salience of behavioral experiences.
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Affiliation(s)
- Dillon J. McGovern
- Department of Psychology and Neuroscience, University of Colorado Boulder, 2860 Wilderness Pl, Boulder, CO 80301
| | - Alysabeth Phillips
- Department of Psychology and Neuroscience, University of Colorado Boulder, 2860 Wilderness Pl, Boulder, CO 80301
| | - Annie Ly
- Department of Psychology and Neuroscience, University of Colorado Boulder, 2860 Wilderness Pl, Boulder, CO 80301
| | - Emily D. Prévost
- Department of Psychology and Neuroscience, University of Colorado Boulder, 2860 Wilderness Pl, Boulder, CO 80301
| | - Lucy Ward
- Department of Psychology and Neuroscience, University of Colorado Boulder, 2860 Wilderness Pl, Boulder, CO 80301
| | - Kayla Siletti
- Department of Psychology and Neuroscience, University of Colorado Boulder, 2860 Wilderness Pl, Boulder, CO 80301
| | - Yoon Seok Kim
- Department of Psychiatry and Behavioral Sciences, Stanford University, Stanford, CA 94305, USA
| | - Lief E. Fenno
- Department of Psychiatry and Behavioral Sciences, Stanford University, Stanford, CA 94305, USA
- Current address: Department of Neuroscience, Dell Medical School, The University of Texas at Austin 78712
| | - Charu Ramakrishnan
- Department of Psychiatry and Behavioral Sciences, Stanford University, Stanford, CA 94305, USA
| | - Karl Deisseroth
- Department of Bioengineering, Stanford University, Stanford, CA 94305, USA
- Department of Psychiatry and Behavioral Sciences, Stanford University, Stanford, CA 94305, USA
- Howard Hughes Medical Institute, Stanford University, Stanford, CA 94305, USA
| | - Christopher P. Ford
- Department of Pharmacology, University of Colorado School of Medicine, Anschutz Medical Campus, Aurora, CO 80045
| | - David H. Root
- Department of Psychology and Neuroscience, University of Colorado Boulder, 2860 Wilderness Pl, Boulder, CO 80301
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Bhimani RV, Rzepecki L, Park J, Mietlicki-Baase EG. Ventral Tegmental Area Amylin Receptor Activation Differentially Modulates Mesolimbic Dopamine Signaling in Response to Fat versus Sugar. eNeuro 2024; 11:ENEURO.0133-24.2024. [PMID: 38806231 PMCID: PMC11164843 DOI: 10.1523/eneuro.0133-24.2024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2024] [Accepted: 04/02/2024] [Indexed: 05/30/2024] Open
Abstract
Amylin, a pancreatic hormone that is cosecreted with insulin, has been highlighted as a potential treatment target for obesity. Amylin receptors are distributed widely throughout the brain and are coexpressed on mesolimbic dopamine neurons. Activation of amylin receptors is known to reduce food intake, but the neurochemical mechanisms behind this remain to be elucidated. Amylin receptor activation in the ventral tegmental area (VTA), a key dopaminergic nucleus in the mesolimbic reward system, has a potent ability to suppress intake of palatable fat and sugar solutions. Although previous work has demonstrated that VTA amylin receptor activation can dampen mesolimbic dopamine signaling elicited by random delivery of sucrose, whether this is also the case for fat remains unknown. Herein we tested the hypothesis that amylin receptor activation in the VTA of male rats would attenuate dopamine signaling in the nucleus accumbens core in response to random intraoral delivery of either fat or sugar solutions. Results show that fat solution produces a greater potentiation of accumbens dopamine than an isocaloric sucrose solution. Moreover, activation of VTA amylin receptors elicits a more robust suppression of accumbens dopamine signaling in response to fat solution than to sucrose. Taken together these results shed new light on the amylin system as a therapeutic target for obesity and emphasize the reinforcing nature of high-fat/high-sugar diets.
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Affiliation(s)
- Rohan V Bhimani
- Neuroscience Program, University at Buffalo, State University of New York, Buffalo, New York 14214-3005
- Department of Biotechnical and Clinical Laboratory Sciences, University at Buffalo, State University of New York, Buffalo, New York 14214-3005
| | - Lily Rzepecki
- Department of Biotechnical and Clinical Laboratory Sciences, University at Buffalo, State University of New York, Buffalo, New York 14214-3005
| | - Jinwoo Park
- Neuroscience Program, University at Buffalo, State University of New York, Buffalo, New York 14214-3005
- Department of Biotechnical and Clinical Laboratory Sciences, University at Buffalo, State University of New York, Buffalo, New York 14214-3005
- Department of Pharmacology and Toxicology, University at Buffalo, State University of New York, Buffalo, New York 14214-3005
| | - Elizabeth G Mietlicki-Baase
- Neuroscience Program, University at Buffalo, State University of New York, Buffalo, New York 14214-3005
- Department of Exercise and Nutrition Sciences, University at Buffalo, State University of New York, Buffalo, New York 14214-3005
- Center for Ingestive Behavior Research, University at Buffalo, State University of New York, Buffalo, New York 14214-3005
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Cordeira J. Daily replacement of very high-fat diet stabilizes food intake and improves mouse welfare by ensuring food quality. PLoS One 2023; 18:e0291347. [PMID: 37721935 PMCID: PMC10506720 DOI: 10.1371/journal.pone.0291347] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2023] [Accepted: 08/27/2023] [Indexed: 09/20/2023] Open
Abstract
Researchers are obligated to ensure food quality and provide laboratory animals with a palatable diet. Factors influencing the quality and palatability of very high-fat diet (VHFD), a widely used rodent diet, however, are understudied. We conducted experiments to establish best practices for ensuring the quality of VHFD and to improve mouse welfare. We found that VHFD in the food hopper was vulnerable first to dehydration and then oxidation within 7-days, leading to dramatic changes in food intake and food preference behavior in mice. Mitigating dehydration and oxidation of VHFD by replacing food daily, rather than weekly, stabilized feeding behavior without effect on overall cardio-metabolic health. Importantly, daily replacement of VHFD also reduced measures of anxiety-like behavior in the open field test. Refining husbandry practices to include daily replacement of VHFD can therefore ensure VHFD quality and improve animal welfare. Standardizing the practice of daily VHFD replacement may also prevent experimental confound and improve experimental reproducibility and replicability.
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Affiliation(s)
- Joshua Cordeira
- Department of Biology, Western Connecticut State University, Danbury, Connecticut, United States of America
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Emmons H, Wallace C, Fordahl S. Interleukin-6 and tumor necrosis factor-α attenuate dopamine release in mice fed a high-fat diet, but not medium or low-fat diets. Nutr Neurosci 2023; 26:864-874. [PMID: 35900193 PMCID: PMC9883593 DOI: 10.1080/1028415x.2022.2103613] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Chronic low-grade inflammation is associated with a state of diet-induced obesity that impacts systemic tissues and can cross the blood-brain barrier to act directly on the brain. The extent to which pro-inflammatory cytokines released in these conditions affect dopamine presynaptic neurotransmission has not been previously investigated. The purpose of this study was to examine how dopamine terminals are affected by pro-inflammatory cytokines, and to determine if dietary fat consumption potentiates cytokine effects on dopamine release and reuptake rate in the nucleus accumbens (NAc). Male and female C57BL/6J mice were fed high, medium, or low-fat diets (60%, 30%, or 10% total kcals from fat, respectively) for six weeks. Fast scan cyclic voltammetry (FSCV) was used to measure dopamine release and reuptake rate in the NAc core from ex vivo coronal brain slices. Electrically evoked dopamine release and the maximal rate of dopamine reuptake (Vmax) were significantly lower in mice fed the 30% and 60% high-fat diets compared to the 10% low-fat group (p < 0.05). IL-6 5 or 10 nM or TNFα 30 or 300 nM was added to artificial cerebrospinal fluid (aCSF) bathed over brain slices during FSCV. No effect on dopamine release or Vmax was observed with lower concentrations. However, 10 nM IL-6 and 300 nM TNFα significantly reduced dopamine release in the 60% fat group (p < 0.05). No effect of added cytokine was observed on Vmax. Overall, these data provide evidence that dietary fat increases neural responsiveness to cytokines, which may help inform comorbidities between diet-induced obesity and depression or other mood disorders.
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Affiliation(s)
- H.A. Emmons
- UNC Greensboro, Department of Nutrition, Greensboro NC
| | - C.W. Wallace
- UNC Greensboro, Department of Nutrition, Greensboro NC
- Wake Forest School of Medicine, Physiology and Pharmacology, Winston-Salem NC
| | - S.C. Fordahl
- UNC Greensboro, Department of Nutrition, Greensboro NC
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Amchova P, Ruda-Kucerova J. Depressive-like phenotype enhances relapse of nicotine seeking after forced abstinence in rats. World J Biol Psychiatry 2023; 24:46-57. [PMID: 35473452 DOI: 10.1080/15622975.2022.2070665] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
OBJECTIVE Comorbidity of depression and drug addiction is common, but effective treatment is missing. A rat model combining the olfactory bulbectomy (OBX) model and IV drug self-administration has provided evidence of differential reactivity of the OBX rats towards drugs of abuse. This study evaluates nicotine taking and seeking behaviour in this model. METHODS Adult male Wistar rats were used; in one group, the OBX was performed while the other group was sham-operated. After three weeks of nicotine self-administration (fixed ratio-1 schedule), rats underwent two weeks of forced abstinence followed by a drug-free relapse-like session. Two doses of nicotine were studied: 0.019 and 0.030 mg/kg per infusion. The locomotor test took place before the self-administration protocol and on the first day of abstinence. RESULTS OBX induced characteristic hyperactive locomotor phenotype. OBX rats self-administered more nicotine in the experiment using 0.019 mg/kg per infusion, but they reached lower drug intake in the study using 0.030 mg/kg per infusion. However, relapse of nicotine seeking after forced abstinence was significantly higher in the OBX groups in both cohorts. CONCLUSION These results are in line with previous studies showing OBX-induced dissimilarities in drug-seeking and drug-taking and represent complementary information to reports on other substances.
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Affiliation(s)
- Petra Amchova
- Department of Pharmacology, Faculty of Medicine, Masaryk University, Brno, Czechia
| | - Jana Ruda-Kucerova
- Department of Pharmacology, Faculty of Medicine, Masaryk University, Brno, Czechia
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Joshi A, Schott M, la Fleur SE, Barrot M. Role of the striatal dopamine, GABA and opioid systems in mediating feeding and fat intake. Neurosci Biobehav Rev 2022; 139:104726. [PMID: 35691472 DOI: 10.1016/j.neubiorev.2022.104726] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2021] [Revised: 12/08/2021] [Accepted: 06/05/2022] [Indexed: 10/18/2022]
Abstract
Food intake, which is a highly reinforcing behavior, provides nutrients required for survival in all animals. However, when fat and sugar consumption goes beyond the daily needs, it can favor obesity. The prevalence and severity of this health problem has been increasing with time. Besides covering nutrient and energy needs, food and in particular its highly palatable components, such as fats, also induce feelings of joy and pleasure. Experimental evidence supports a role of the striatal complex and of the mesolimbic dopamine system in both feeding and food-related reward processing, with the nucleus accumbens as a key target for reward or reinforcing-associated signaling during food intake behavior. In this review, we provide insights concerning the impact of feeding, including fat intake, on different types of receptors and neurotransmitters present in the striatal complex. Reciprocally, we also cover the evidence for a modulation of palatable food intake by different neurochemical systems in the striatal complex and in particular the nucleus accumbens, with a focus on dopamine, GABA and the opioid system.
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Affiliation(s)
- Anil Joshi
- Centre National de la Recherche Scientifique, Université de Strasbourg, Institut des Neurosciences Cellulaires et Intégratives, Strasbourg, France; Amsterdam UMC, University of Amsterdam, Laboratory of Endocrinology, Department of Clinical Chemistry, Amsterdam Gastroenterology & Metabolism, Amsterdam, the Netherlands; Amsterdam UMC, University of Amsterdam, Department of Endocrinology & Metabolism, Amsterdam Neuroscience, Amsterdam, the Netherlands; Metabolism and Reward Group, Netherlands Institute for Neuroscience, An Institute of the Royal Netherlands Academy of Arts and Sciences (KNAW), Amsterdam, the Netherlands
| | - Marion Schott
- Centre National de la Recherche Scientifique, Université de Strasbourg, Institut des Neurosciences Cellulaires et Intégratives, Strasbourg, France
| | - Susanne Eva la Fleur
- Amsterdam UMC, University of Amsterdam, Laboratory of Endocrinology, Department of Clinical Chemistry, Amsterdam Gastroenterology & Metabolism, Amsterdam, the Netherlands; Amsterdam UMC, University of Amsterdam, Department of Endocrinology & Metabolism, Amsterdam Neuroscience, Amsterdam, the Netherlands; Metabolism and Reward Group, Netherlands Institute for Neuroscience, An Institute of the Royal Netherlands Academy of Arts and Sciences (KNAW), Amsterdam, the Netherlands.
| | - Michel Barrot
- Centre National de la Recherche Scientifique, Université de Strasbourg, Institut des Neurosciences Cellulaires et Intégratives, Strasbourg, France.
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Lewis RG, Florio E, Punzo D, Borrelli E. The Brain's Reward System in Health and Disease. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2021; 1344:57-69. [PMID: 34773226 DOI: 10.1007/978-3-030-81147-1_4] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Rhythmic gene expression is found throughout the central nervous system. This harmonized regulation can be dependent on- and independent of- the master regulator of biological clocks, the suprachiasmatic nucleus (SCN). Substantial oscillatory activity in the brain's reward system is regulated by dopamine. While light serves as a primary time-giver (zeitgeber) of physiological clocks and synchronizes biological rhythms in 24-h cycles, nonphotic stimuli have a profound influence over circadian biology. Indeed, reward-related activities (e.g., feeding, exercise, sex, substance use, and social interactions), which lead to an elevated level of dopamine, alters rhythms in the SCN and the brain's reward system. In this chapter, we will discuss the influence of the dopaminergic reward pathways on circadian system and the implication of this interplay on human health.
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Affiliation(s)
- Robert G Lewis
- School of Medicine, Department of Microbiology and Molecular Genetics, INSERMU1233, Center for Epigenetics and Metabolism, University of California - Irvine, Irvine, CA, USA
| | - Ermanno Florio
- School of Medicine, Department of Microbiology and Molecular Genetics, INSERMU1233, Center for Epigenetics and Metabolism, University of California - Irvine, Irvine, CA, USA
| | - Daniela Punzo
- School of Medicine, Department of Microbiology and Molecular Genetics, INSERMU1233, Center for Epigenetics and Metabolism, University of California - Irvine, Irvine, CA, USA
| | - Emiliana Borrelli
- School of Medicine, Department of Microbiology and Molecular Genetics, INSERMU1233, Center for Epigenetics and Metabolism, University of California - Irvine, Irvine, CA, USA. .,University of California - Irvine, Irvine, CA, USA.
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8
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Greenberg D, St. Peter JV. Sugars and Sweet Taste: Addictive or Rewarding? INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2021; 18:ijerph18189791. [PMID: 34574716 PMCID: PMC8468293 DOI: 10.3390/ijerph18189791] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 05/29/2021] [Revised: 09/10/2021] [Accepted: 09/14/2021] [Indexed: 11/16/2022]
Abstract
The notion of food "addiction" often focuses on the overconsumption of sweet tasting foods or so-called sugar "addiction". In the extreme, some have suggested that sugar and sweet tastes elicit neural and behavioral responses analogous to those observed with drugs of abuse. These concepts are complicated by the decades long uncertainty surrounding the validity and reproducibility of functional magnetic resonance imaging (fMRI) methodologies used to characterize neurobiological pathways related to sugar and sweet taste stimuli. There are also questions of whether sweet taste or post-ingestion metabolic consequences of sugar intake would lead to addiction or excessive caloric intake. Here, we present a focused narrative review of literature related to the reward value of sweet taste which suggests that reward value can be confounded with the construct of "addictive potential". Our review seeks to clarify some key distinctions between these constructs and questions the applicability of the addiction construct to human over-eating behaviors. To adequately frame this broad discussion requires the flexibility offered by the narrative review paradigm. We present selected literature on: techniques used to link sugar and sweet tastes to addiction neurobiology and behaviors; sugar and sweet taste "addiction"; the relationship of low calorie sweetener (LCS) intake to addictive behaviors and total calorie intake. Finally, we examined the reward value of sweet tastes and contrasted that with the literature describing addiction. The lack of reproducibility of fMRI data remains problematic for attributing a common neurobiological pathway activation of drugs and foods as conclusive evidence for sugar or sweet taste "addiction". Moreover, the complicated hedonics of sweet taste and reward value are suggested by validated population-level data which demonstrate that the consumption of sweet taste in the absence of calories does not increase total caloric intake. We believe the neurobiologies of reward value and addiction to be distinct and disagree with application of the addiction model to sweet food overconsumption. Most hypotheses of sugar "addiction" attribute the hedonics of sweet foods as the equivalent of "addiction". Further, when addictive behaviors and biology are critically examined in totality, they contrast dramatically from those associated with the desire for sweet taste. Finally, the evidence is strong that responses to the palatability of sweets rather than their metabolic consequences are the salient features for reward value. Thus, given the complexity of the controls of food intake in humans, we question the usefulness of the "addiction" model in dissecting the causes and effects of sweet food over-consumption.
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Affiliation(s)
- Danielle Greenberg
- NutriSci Inc., Mt. Kisco, NY 10549, USA
- Correspondence: ; Tel.: +1-(914)572-2972
| | - John V. St. Peter
- Deptartment of Experimental & Clinical Pharmacology, University of Minnesota, Minneapolis, MN 55455, USA;
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Berland C, Small DM, Luquet S, Gangarossa G. Dietary lipids as regulators of reward processes: multimodal integration matters. Trends Endocrinol Metab 2021; 32:693-705. [PMID: 34148784 DOI: 10.1016/j.tem.2021.05.008] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/03/2021] [Revised: 05/08/2021] [Accepted: 05/24/2021] [Indexed: 02/03/2023]
Abstract
The abundance of energy-dense and palatable diets in the modern food environment tightly contributes to the obesity pandemic. The reward circuit participates to the regulation of body homeostasis by integrating energy-related signals with neural substrates encoding cognitive and motivational components of feeding behaviors. Obesity and lipid-rich diets alter dopamine (DA) transmission leading to reward dysfunctions and food overconsumption. Recent reports indicate that dietary lipids can act, directly and indirectly, as functional modulators of the DA circuit. This raises the possibility that nutritional or genetic conditions affecting 'lipid sensing' mechanisms might lead to maladaptations of the DA system. Here, we discuss the most recent findings connecting dietary lipid sensing with DA signaling and its multimodal influence on circuits regulating food-reward processes.
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Affiliation(s)
- Chloé Berland
- Université de Paris, BFA, UMR 8251, CNRS, F-75013 Paris, France; Department of Medicine, The Naomi Berrie Diabetes Center, Columbia University, New York, NY 10032, USA
| | - Dana M Small
- Department of Psychiatry, and the Modern Diet and Physiology Research Center, Yale University School of Medicine, New Haven, CT 06510, USA
| | - Serge Luquet
- Université de Paris, BFA, UMR 8251, CNRS, F-75013 Paris, France.
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Replacing a Palatable High-Fat Diet with a Low-Fat Alternative Heightens κ-Opioid Receptor Control over Nucleus Accumbens Dopamine. Nutrients 2021; 13:nu13072341. [PMID: 34371851 PMCID: PMC8308677 DOI: 10.3390/nu13072341] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2021] [Revised: 06/22/2021] [Accepted: 07/06/2021] [Indexed: 12/04/2022] Open
Abstract
Diet-induced obesity reduces dopaminergic neurotransmission in the nucleus accumbens (NAc), and stressful weight loss interventions could promote cravings for palatable foods high in fat and sugar that stimulate dopamine. Activation of κ-opioid receptors (KORs) reduces synaptic dopamine, but contribution of KORs to lower dopamine tone after dietary changes is unknown. Therefore, the purpose of this study was to determine the function of KORs in C57BL/6 mice that consumed a 60% high-fat diet (HFD) for six weeks followed by replacement of HFD with a control 10% fat diet for one day or one week. HFD replacement induced voluntary caloric restriction and weight loss. However, fast-scan cyclic voltammetry revealed no differences in baseline dopamine parameters, whereas sex effects were revealed during KOR stimulation. NAc core dopamine release was reduced by KOR agonism after one day of HFD replacement in females but after one week of HFD replacement in males. Further, elevated plus-maze testing revealed no diet effects during HFD replacement on overt anxiety. These results suggest that KORs reduce NAc dopamine tone and increase food-related anxiety during dietary weight loss interventions that could subsequently promote palatable food cravings and inhibit weight loss.
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Obesity and dietary fat influence dopamine neurotransmission: exploring the convergence of metabolic state, physiological stress, and inflammation on dopaminergic control of food intake. Nutr Res Rev 2021; 35:236-251. [PMID: 34184629 DOI: 10.1017/s0954422421000196] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
The aim of this review is to explore how metabolic changes induced by diets high in saturated fat (HFD) affect nucleus accumbens (NAc) dopamine neurotransmission and food intake, and to explore how stress and inflammation influence this process. Recent evidence linked diet-induced obesity and HFD with reduced dopamine release and reuptake. Altered dopamine neurotransmission could disrupt satiety circuits between NAc dopamine terminals and projections to the hypothalamus. The NAc directs learning and motivated behaviours based on homeostatic needs and psychological states. Therefore, impaired dopaminergic responses to palatable food could contribute to weight gain by disrupting responses to food cues or stress, which impacts type and quantity of food consumed. Specifically, saturated fat promotes neuronal resistance to anorectic hormones and activation of immune cells that release proinflammatory cytokines. Insulin has been shown to regulate dopamine neurotransmission by enhancing satiety, but less is known about effects of diet-induced stress. Therefore, changes to dopamine signalling due to HFD warrant further examination to characterise crosstalk of cytokines with endocrine and neurotransmitter signals. A HFD promotes a proinflammatory environment that may disrupt neuronal endocrine function and dopamine signalling that could be exacerbated by the hypothalamic-pituitary-adrenal and κ-opioid receptor stress systems. Together, these adaptive changes may dysregulate eating by changing NAc dopamine during hedonic versus homeostatic food intake. This could drive palatable food cravings during energy restriction and hinder weight loss. Understanding links between HFD and dopamine neurotransmission will inform treatment strategies for diet-induced obesity and identify molecular candidates for targeted therapeutics.
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12
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Joshi A, Faivre F, la Fleur SE, Barrot M. Midbrain and Lateral Nucleus Accumbens Dopamine Depletion Affects Free-choice High-fat high-sugar Diet Preference in Male Rats. Neuroscience 2021; 467:171-184. [PMID: 34048800 DOI: 10.1016/j.neuroscience.2021.05.022] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2021] [Revised: 04/16/2021] [Accepted: 05/19/2021] [Indexed: 12/25/2022]
Abstract
Dopamine influences food intake behavior. Reciprocally, food intake, especially of palatable dietary items, can modulate dopamine-related brain circuitries. Among these reciprocal impacts, it has been observed that an increased intake of dietary fat results in blunted dopamine signaling and, to compensate this lowered dopamine function, caloric intake may subsequently increase. To determine how dopamine regulates food preference we performed 6-hydroxydopamine (6-OHDA) lesions, depleting dopamine in specific brain regions in male Sprague Dawley rats. Food preference was assessed by providing the rats with free choice access to control diet, fat, 20% sucrose and tap water. Rats with midbrain lesions targeting the substantia nigra (which is also a model of Parkinson's disease) consumed fewer calories, as reflected by a decrease in control diet intake, but they surprisingly displayed an increase in fat intake, without change in the sucrose solution intake compared to sham animals. To determine which of the midbrain dopamine projections may contribute to this effect, we next compared the impact of 6-OHDA lesions of terminal fields, targeting the dorsal striatum, the lateral nucleus accumbens and the medial nucleus accumbens. We found that 6-OHDA lesion of the lateral nucleus accumbens, but not of the dorsal striatum or the medial nucleus accumbens, led to increased fat intake. These findings indicate a role for lateral nucleus accumbens dopamine in regulating food preference, in particular the intake of fat.
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Affiliation(s)
- Anil Joshi
- Centre National de la Recherche Scientifique, Université de Strasbourg, Institut des Neurosciences Cellulaires et Intégratives, Strasbourg, France; Amsterdam UMC, University of Amsterdam, Laboratory of Endocrinology, Department of Clinical Chemistry, Amsterdam Gastroenterology & Metabolism, Amsterdam, the Netherlands; Amsterdam UMC, University of Amsterdam, Department of Endocrinology & Metabolism, Amsterdam Neuroscience, Amsterdam, the Netherlands; Metabolism and Reward Group, Netherlands Institute for Neuroscience, An Institute of the Royal Netherlands Academy of Arts and Sciences (KNAW), Amsterdam, the Netherlands
| | - Fanny Faivre
- Centre National de la Recherche Scientifique, Université de Strasbourg, Institut des Neurosciences Cellulaires et Intégratives, Strasbourg, France
| | - Susanne Eva la Fleur
- Amsterdam UMC, University of Amsterdam, Laboratory of Endocrinology, Department of Clinical Chemistry, Amsterdam Gastroenterology & Metabolism, Amsterdam, the Netherlands; Amsterdam UMC, University of Amsterdam, Department of Endocrinology & Metabolism, Amsterdam Neuroscience, Amsterdam, the Netherlands; Metabolism and Reward Group, Netherlands Institute for Neuroscience, An Institute of the Royal Netherlands Academy of Arts and Sciences (KNAW), Amsterdam, the Netherlands
| | - Michel Barrot
- Centre National de la Recherche Scientifique, Université de Strasbourg, Institut des Neurosciences Cellulaires et Intégratives, Strasbourg, France.
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Faulkner ML, Momenan R, Leggio L. A neuroimaging investigation into the role of peripheral metabolic biomarkers in the anticipation of reward in alcohol use. Drug Alcohol Depend 2021; 221:108638. [PMID: 33667782 PMCID: PMC8527598 DOI: 10.1016/j.drugalcdep.2021.108638] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/28/2020] [Revised: 01/28/2021] [Accepted: 02/01/2021] [Indexed: 11/28/2022]
Abstract
BACKGROUND The relationship between alcohol use and metabolism has focused on the effects of alcohol use on metabolic factors. Metabolic factors, such as triglycerides, cholesterol, and glucose, have been shown to be associated with increased risk for heavy alcohol consumption and alcohol use disorder (AUD). It's been suggested that changes in metabolic factors may play a role in reward seeking behaviors and pathways. Studies on feeding behavior and obesity revealed the role of triglycerides in neural response to food cues in neurocircuitry regulating reward and feeding behaviors. This study aimed to explore the relationship of peripheral metabolism, alcohol use, and reward processing in individuals that use alcohol. METHODS Ninety participants from a previously collected dataset were included in the analysis. Participants were treatment seeking, detoxified individuals with AUD and healthy individuals without AUD, with the following metabolic biomarkers: triglyceride, glucose, high- and low-density cholesterol, and HbA1c levels. Participants completed a neuroimaging version of the Monetary Incentive Delay task (MID). RESULTS Correlations on peripheral metabolic biomarkers, alcohol use, and neural activity during reward anticipation and outcome during the MID task were not significant. Mediation models revealed triglycerides and high-density cholesterol had significant effects on left anterior insula during anticipation of potential monetary loss and this effect was not mediated by alcohol use. CONCLUSION Limbic recruitment by anticipation of monetary rewards revealed an independent relationship with peripheral metabolism and was not affected by individual differences in alcohol use, despite the effects of alcohol use on metabolic markers and reward processing neural circuitry.
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Affiliation(s)
- Monica L. Faulkner
- Clinical Psychoneuroendocrinology and Neuropsychopharmacology Section, Translational Addiction Medicine Branch, National Institute on Drug Abuse Intramural Research Program and National Institute on Alcohol Abuse and Alcoholism Division of Intramural Clinical and Biological Research, National Institutes of Health, Baltimore and Bethesda, MD, USA, 20814
| | - Reza Momenan
- Clinical Neuroimaging Research Core, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, MD, USA 20814
| | - Lorenzo Leggio
- Clinical Psychoneuroendocrinology and Neuropsychopharmacology Section, Translational Addiction Medicine Branch, National Institute on Drug Abuse Intramural Research Program and National Institute on Alcohol Abuse and Alcoholism Division of Intramural Clinical and Biological Research, National Institutes of Health, Baltimore and Bethesda, MD 20814, USA; Medication Development Program, National Institute on Drug Abuse Intramural Research Program, National Institutes of Health, Baltimore, MD 21224, USA; Center for Alcohol and Addiction Studies, Department of Behavioral and Social Sciences, Brown University, Providence, RI 02903, USA; Division of Addiction Medicine, Department of Medicine, School of Medicine, Johns Hopkins University, Baltimore, MD 21224, USA; Department of Neuroscience, Georgetown University Medical Center, Washington DC 20057, USA.
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14
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Gastelum C, Perez L, Hernandez J, Le N, Vahrson I, Sayers S, Wagner EJ. Adaptive Changes in the Central Control of Energy Homeostasis Occur in Response to Variations in Energy Status. Int J Mol Sci 2021; 22:2728. [PMID: 33800452 PMCID: PMC7962960 DOI: 10.3390/ijms22052728] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2021] [Revised: 03/03/2021] [Accepted: 03/04/2021] [Indexed: 12/15/2022] Open
Abstract
Energy homeostasis is regulated in coordinate fashion by the brain-gut axis, the homeostatic energy balance circuitry in the hypothalamus and the hedonic energy balance circuitry comprising the mesolimbcortical A10 dopamine pathway. Collectively, these systems convey and integrate information regarding nutrient status and the rewarding properties of ingested food, and formulate it into a behavioral response that attempts to balance fluctuations in consumption and food-seeking behavior. In this review we start with a functional overview of the homeostatic and hedonic energy balance circuitries; identifying the salient neural, hormonal and humoral components involved. We then delve into how the function of these circuits differs in males and females. Finally, we turn our attention to the ever-emerging roles of nociceptin/orphanin FQ (N/OFQ) and pituitary adenylate cyclase-activating polypeptide (PACAP)-two neuropeptides that have garnered increased recognition for their regulatory impact in energy homeostasis-to further probe how the imposed regulation of energy balance circuitry by these peptides is affected by sex and altered under positive (e.g., obesity) and negative (e.g., fasting) energy balance states. It is hoped that this work will impart a newfound appreciation for the intricate regulatory processes that govern energy homeostasis, as well as how recent insights into the N/OFQ and PACAP systems can be leveraged in the treatment of conditions ranging from obesity to anorexia.
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Affiliation(s)
- Cassandra Gastelum
- Graduate College of Biomedical Sciences, Western University of Health Sciences, Pomona, CA 91766, USA; (C.G.); (L.P.); (J.H.); (N.L.); (I.V.); (S.S.)
| | - Lynnea Perez
- Graduate College of Biomedical Sciences, Western University of Health Sciences, Pomona, CA 91766, USA; (C.G.); (L.P.); (J.H.); (N.L.); (I.V.); (S.S.)
| | - Jennifer Hernandez
- Graduate College of Biomedical Sciences, Western University of Health Sciences, Pomona, CA 91766, USA; (C.G.); (L.P.); (J.H.); (N.L.); (I.V.); (S.S.)
| | - Nikki Le
- Graduate College of Biomedical Sciences, Western University of Health Sciences, Pomona, CA 91766, USA; (C.G.); (L.P.); (J.H.); (N.L.); (I.V.); (S.S.)
| | - Isabella Vahrson
- Graduate College of Biomedical Sciences, Western University of Health Sciences, Pomona, CA 91766, USA; (C.G.); (L.P.); (J.H.); (N.L.); (I.V.); (S.S.)
| | - Sarah Sayers
- Graduate College of Biomedical Sciences, Western University of Health Sciences, Pomona, CA 91766, USA; (C.G.); (L.P.); (J.H.); (N.L.); (I.V.); (S.S.)
| | - Edward J. Wagner
- Graduate College of Biomedical Sciences, Western University of Health Sciences, Pomona, CA 91766, USA; (C.G.); (L.P.); (J.H.); (N.L.); (I.V.); (S.S.)
- College of Osteopathic Medicine of the Pacific, Western University of Health Sciences, Pomona, CA 91766, USA
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15
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Ma R, Mikhail ME, Culbert KM, Johnson AW, Sisk CL, Klump KL. Ovarian Hormones and Reward Processes in Palatable Food Intake and Binge Eating. Physiology (Bethesda) 2021; 35:69-78. [PMID: 31799907 DOI: 10.1152/physiol.00013.2019] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Ovarian hormones are associated with risk for binge eating in women. Recent animal and human studies suggest that food-related reward processing may be one set of neurobiological factors that contribute to these relationships, but additional studies are needed to confirm and extend findings.
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Affiliation(s)
- Ruofan Ma
- Department of Psychology, Michigan State University, East Lansing, Michigan
| | - Megan E Mikhail
- Department of Psychology, Michigan State University, East Lansing, Michigan
| | - Kristen M Culbert
- Department of Psychology, University of Nevada-Las Vegas, Las Vegas, Nevada
| | - Alex W Johnson
- Neuroscience Program, Michigan State University, East Lansing, Michigan
| | - Cheryl L Sisk
- Neuroscience Program, Michigan State University, East Lansing, Michigan
| | - Kelly L Klump
- Department of Psychology, Michigan State University, East Lansing, Michigan
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16
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Wallace CW, Loudermilt MC, Fordahl SC. Effect of fasting on dopamine neurotransmission in subregions of the nucleus accumbens in male and female mice. Nutr Neurosci 2020; 25:1338-1349. [PMID: 33297887 DOI: 10.1080/1028415x.2020.1853419] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Diets high in saturated fat (HFD) disrupt dopamine neurotransmission, whereas fasting alters tonic and phasic dopamine release to drive motivation and food consumption. However, functional compartments in the nucleus accumbens (NAc) influencing these effects are not well characterized, and sex comparisons have not been made. This study sought to determine whether consumption of a HFD, sex, or being fed versus fasted altered baseline dopamine release and reuptake throughout NAc subregions. Male and female C57BL/6 mice were fed a control diet or nutrient matched HFD for six weeks. Ex-vivo fast-scan cyclic voltammetry revealed females had significantly slower dopamine reuptake in the NAc core than males when fed ad lib control diet. Fasting enhanced dopamine release and reuptake in the NAc core but not the medioventral shell. Further, being fasted versus fed significantly increased dopamine release throughout the NAc core in control males but specifically promoted release and reuptake in only the ventrolateral core of HF-fed males, effects which were lacking in females. Finally, fasting promoted dopamine release and reuptake in the rostral NAc core of controls and more caudally in HFD groups. These data support that dopamine neurotransmission is heterogeneous in NAc subregions and suggest the ventrolateral core is responsive to energy state. Furthermore, a rostrocaudal gradient in the NAc core might control valence responses to fasting that could promote overeating after chronic HFD consumption.
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Affiliation(s)
- C W Wallace
- Department of Nutrition, UNC Greensboro, Greensboro, NC, USA
| | - M C Loudermilt
- Department of Nutrition, UNC Greensboro, Greensboro, NC, USA
| | - S C Fordahl
- Department of Nutrition, UNC Greensboro, Greensboro, NC, USA
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17
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Access schedules mediate the impact of high fat diet on ethanol intake and insulin and glucose function in mice. Alcohol 2020; 86:45-56. [PMID: 32224218 DOI: 10.1016/j.alcohol.2020.03.007] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2019] [Revised: 03/17/2020] [Accepted: 03/18/2020] [Indexed: 12/13/2022]
Abstract
Alcoholism and high fat diet (HFD)-induced obesity individually promote insulin resistance and glucose intolerance in clinical populations, increasing risk for metabolic diseases. HFD can also stimulate alcohol intake in short-term clinical studies. Unfortunately, there is currently a disconnect between animal models and the clinical findings, as animal studies typically show that HFD decreases ethanol intake while ethanol intake mitigates HFD-induced effects on insulin and glucose dysfunction. However, most previous animal studies utilized forced or continuous HFD and/or ethanol. In three experiments we sought to determine whether HFD (HFD = 60% calories from fat) vs. control diet (chow = 16% fat) alters voluntary two-bottle choice ethanol intake in male C57Bl/6J mice given differing access schedules for 6-7 weeks, and we assessed the resultant impact on metabolic function via insulin and glucose tolerance tests. Experiment 1: Unlimited Access Ethanol + HFD (UAE + HFD; n = 15; 10% ethanol v/v, ad libitum diet and ethanol) or UAE + Chow (n = 15). Experiment 2: Limited Access Ethanol + HFD (LAE + HFD; n = 15; ethanol = 4 h/day; 3 days/week, ad libitum diet) or LAE + Chow (n = 15) with increasing ethanol concentrations (10%, 15%, 20%). Experiment 3: Intermittent HFD with limited access to ethanol (iHFD-E; HFD = single 24-h session/week; ethanol = 4 h/day; 4 days/week) (n = 10). UAE + HFD mice consumed significantly less ethanol and were insulin-resistant and hyperglycemic compared with UAE + Chow mice. LAE + HFD mice consumed ethanol similarly to LAE + Chow mice, but exhibited hyperglycemia, insulin resistance, and glucose intolerance. iHFD-E mice displayed binge eating-like behaviors and consumed significantly more ethanol than mice given ad libitum chow or HFD. iHFD-E mice did not have significantly altered body composition, but developed insulin insensitivity and glucose intolerance. These findings suggest that access schedules influence HFD effects on ethanol consumption and resultant metabolic dysfunction, ethanol intake does not improve HFD-induced metabolic dysfunction, and binge eating-like behaviors can transfer to binge drinking behaviors.
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18
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Jin T, Jiang Z, Luan X, Qu Z, Guo F, Gao S, Xu L, Sun X. Exogenous Orexin-A Microinjected Into Central Nucleus of the Amygdala Modulates Feeding and Gastric Motility in Rats. Front Neurosci 2020; 14:274. [PMID: 32410931 PMCID: PMC7198841 DOI: 10.3389/fnins.2020.00274] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2019] [Accepted: 03/10/2020] [Indexed: 12/16/2022] Open
Abstract
Orexin-A is a circulating neuropeptide and neurotransmitter that regulates food intake and gastric motility. The central nucleus of the amygdala (CeA), which regulates feeding behavior and gastric function, expresses the orexin-1 receptor. The aim of this study was to evaluate the effects of microinjection of exogenous orexin-A into the CeA, on food intake and gastric motility, and to explore the mechanisms of these effects. Normal chow and high fat food (HFF) intake were measured, gastric motility and gastric emptying were evaluated, extracellular single unit firing was recorded, and c-fos expression was determined. The results showed that microinjection of orexin-A into the CeA resulted in increased HFF intake but did not affect normal chow intake. This effect was blocked by an orexin-1 receptor antagonist-SB-334867 and was partially blocked by a dopamine D1 receptor antagonist-SCH-23390. Gastric motility and gastric emptying were enhanced by orexin-A, and the former effect was abolished by subdiaphragmatic vagotomy. The firing frequency of gastric distention-related neurons was regulated by orexin-A via the orexin-1 receptor. Furthermore, c-fos expression was increased in the ventral tegmental area (VTA) and the nucleus accumbens (NAc), the lateral hypothalamus (LHA), and the dorsal motor nucleus of the vagus (DMV) in response to microinjection of orexin-A into the CeA. These findings showed that orexin-A regulated palatable food intake and gastric motility via the CeA. The LHA, the VTA, and the NAc may participate in palatable food intake and the CeA-DMV-vagus-stomach pathway may be involved in regulating gastric motility through the regulation of neuronal activity in the CeA.
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Affiliation(s)
- Tingting Jin
- Department of Physiology and Pathophysiology, School of Basic Medicine, Qingdao University, Qingdao, China
| | - Zhongxin Jiang
- Department of Clinical Laboratory, The Affiliated Hospital of Qingdao University, Qingdao, China
| | - Xiao Luan
- Department of Physiology and Pathophysiology, School of Basic Medicine, Qingdao University, Qingdao, China
| | - Zhuling Qu
- Department of Physiology and Pathophysiology, School of Basic Medicine, Qingdao University, Qingdao, China
| | - Feifei Guo
- Department of Physiology and Pathophysiology, School of Basic Medicine, Qingdao University, Qingdao, China
| | - Shengli Gao
- Department of Physiology and Pathophysiology, School of Basic Medicine, Qingdao University, Qingdao, China
| | - Luo Xu
- Department of Physiology and Pathophysiology, School of Basic Medicine, Qingdao University, Qingdao, China
| | - Xiangrong Sun
- Department of Physiology and Pathophysiology, School of Basic Medicine, Qingdao University, Qingdao, China
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19
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Linehan V, Fang LZ, Parsons MP, Hirasawa M. High-fat diet induces time-dependent synaptic plasticity of the lateral hypothalamus. Mol Metab 2020; 36:100977. [PMID: 32277924 PMCID: PMC7170999 DOI: 10.1016/j.molmet.2020.100977] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/18/2019] [Revised: 02/28/2020] [Accepted: 03/10/2020] [Indexed: 11/15/2022] Open
Abstract
Objective Orexin (ORX) and melanin-concentrating hormone (MCH) neurons in the lateral hypothalamus are critical regulators of energy homeostasis and are thought to differentially contribute to diet-induced obesity. However, it is unclear whether the synaptic properties of these cells are altered by obesogenic diets over time. Methods Rats and mice were fed a control chow or palatable high-fat diet (HFD) for various durations and then synaptic properties of ORX and MCH neurons were examined using exvivo whole-cell patch clamp recording. Confocal imaging was performed to assess the number of excitatory synaptic contacts to these neurons. Results ORX neurons exhibited a transient increase in spontaneous excitatory transmission as early as 1 day up to 1 week of HFD, which returned to control levels with prolonged feeding. Conversely, HFD induced a delayed increase in excitatory synaptic transmission to MCH neurons, which progressively increased as HFD became chronic. This increase occurred before the onset of significant weight gain. These synaptic changes appeared to be due to altered postsynaptic sensitivity or the number of active synaptic contacts depending on cell type and feeding duration. However, HFD induced no change in inhibitory transmission in either cell type at any time point. Conclusions These results suggest that the effects of HFD on feeding-related neurons are cell type-specific and dynamic. This highlights the importance of considering the feeding duration for research and weight loss interventions. ORX neurons may contribute to early hyperphagia, whereas MCH neurons may play a role in the onset and long-term maintenance of diet-induced obesity. High-fat diet increases excitatory transmission to orexin and MCH neurons. Increased excitatory drive to orexin neurons occurs within the first week but is transient. Excitatory synapses to MCH neurons increase with prolonged high-fat diet. Excitatory changes in MCH neurons are delayed but precede significant weight gain. These synaptic changes may contribute to the development and the maintenance of obesity.
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Affiliation(s)
- Victoria Linehan
- Division of Biomedical Sciences, Faculty of Medicine, Memorial University, 300 Prince Philip Drive, St. John's, Newfoundland, A1B 3V6, Canada
| | - Lisa Z Fang
- Division of Biomedical Sciences, Faculty of Medicine, Memorial University, 300 Prince Philip Drive, St. John's, Newfoundland, A1B 3V6, Canada
| | - Matthew P Parsons
- Division of Biomedical Sciences, Faculty of Medicine, Memorial University, 300 Prince Philip Drive, St. John's, Newfoundland, A1B 3V6, Canada
| | - Michiru Hirasawa
- Division of Biomedical Sciences, Faculty of Medicine, Memorial University, 300 Prince Philip Drive, St. John's, Newfoundland, A1B 3V6, Canada.
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20
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Dopaminergic mechanisms in the lateral hypothalamus regulate feeding behavior in association with neuropeptides. Biochem Biophys Res Commun 2019; 519:547-552. [DOI: 10.1016/j.bbrc.2019.09.037] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2019] [Accepted: 09/11/2019] [Indexed: 11/20/2022]
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21
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King G, Baker KD, Bisby MA, Chan D, Cowan CSM, Stylianakis AA, Zimmermann KS, Richardson R. A precision medicine approach to pharmacological adjuncts to extinction: a call to broaden research. Psychopharmacology (Berl) 2019; 236:143-161. [PMID: 30116858 DOI: 10.1007/s00213-018-4999-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/03/2018] [Accepted: 08/07/2018] [Indexed: 12/21/2022]
Abstract
There is a pressing need to improve treatments for anxiety. Although exposure-based therapy is currently the gold-standard treatment, many people either do not respond to this therapy or experience a relapse of symptoms after treatment has ceased. In recent years, there have been many novel pharmacological agents identified in preclinical research that have potential as adjuncts for exposure therapy, yet very few of these are regularly integrated into clinical practice. Unfortunately, the robust effects observed in the laboratory animal often do not translate to a clinical population. In this review, we discuss how age, sex, genetics, stress, medications, diet, alcohol, and the microbiome can vary across a clinical population and yet are rarely considered in drug development. While not an exhaustive list, we have focused on these factors because they have been shown to influence an individual's vulnerability to anxiety and alter the neurotransmitter systems often targeted by pharmacological adjuncts to therapy. We argue that for potential adjuncts to be successfully translated from the lab to the clinic empirical research must be broadened to consider how individual difference factors will influence drug efficacy.
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Affiliation(s)
- Gabrielle King
- School of Psychology, The University of New South Wales, Sydney, Australia.
| | - Kathryn D Baker
- School of Psychology, The University of New South Wales, Sydney, Australia
| | - Madelyne A Bisby
- School of Psychology, The University of New South Wales, Sydney, Australia
| | - Diana Chan
- School of Psychology, The University of New South Wales, Sydney, Australia
| | | | | | | | - Rick Richardson
- School of Psychology, The University of New South Wales, Sydney, Australia
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22
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Wiss DA, Avena N, Rada P. Sugar Addiction: From Evolution to Revolution. Front Psychiatry 2018; 9:545. [PMID: 30464748 PMCID: PMC6234835 DOI: 10.3389/fpsyt.2018.00545] [Citation(s) in RCA: 57] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/12/2018] [Accepted: 10/12/2018] [Indexed: 12/12/2022] Open
Abstract
The obesity epidemic has been widely publicized in the media worldwide. Investigators at all levels have been looking for factors that have contributed to the development of this epidemic. Two major theories have been proposed: (1) sedentary lifestyle and (2) variety and ease of inexpensive palatable foods. In the present review, we analyze how nutrients like sugar that are often used to make foods more appealing could also lead to habituation and even in some cases addiction thereby uniquely contributing to the obesity epidemic. We review the evolutionary aspects of feeding and how they have shaped the human brain to function in "survival mode" signaling to "eat as much as you can while you can." This leads to our present understanding of how the dopaminergic system is involved in reward and its functions in hedonistic rewards, like eating of highly palatable foods, and drug addiction. We also review how other neurotransmitters, like acetylcholine, interact in the satiation processes to counteract the dopamine system. Lastly, we analyze the important question of whether there is sufficient empirical evidence of sugar addiction, discussed within the broader context of food addiction.
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Affiliation(s)
- David A. Wiss
- Fielding School of Public Health, University of California, Los Angeles, Los Angeles, CA, United States
| | - Nicole Avena
- Icahn School of Medicine at Mount Sinai, New York, NY, United States
| | - Pedro Rada
- School of Medicine, University of Los Andes, Mérida, Venezuela
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Contini A, Sanna F, Maccioni P, Colombo G, Argiolas A. Comparison between male and female rats in a model of self-administration of a chocolate-flavored beverage: Behavioral and neurochemical studies. Behav Brain Res 2018; 344:28-41. [PMID: 29427608 DOI: 10.1016/j.bbr.2018.02.004] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2017] [Revised: 01/18/2018] [Accepted: 02/05/2018] [Indexed: 01/13/2023]
Abstract
The existence of sex differences was studied in a rat model of operant self-administration of a chocolate-flavored beverage (CFB), which possesses strong reinforcing properties and is avidly consumed by rats. Whether these differences occurred concomitantly to changes in extracellular dopamine in the dialysate obtained from the nucleus accumbens, was assessed by intracerebral microdialysis. Male, ovariectomized and intact female rats showed similar self-administration profiles, with minor differences in both acquisition and maintenance phases. Intact females self-administered larger amounts of CFB, when expressed per body weight, than males and ovariectomized females, in spite of similar values of lever-responding, latency to the first lever-response and consumption efficiency (a measure of rat's licking effectiveness) in males, ovariectomized and intact females and no difference in breakpoint value and number of lever-responses emerged when males, ovariectomized and intact females were exposed to a progressive ratio schedule of reinforcement. Intracerebral microdialysis revealed a slight but significant increase in dopamine activity in the shell of the nucleus accumbens of male rats when compared to intact female rats during CFB self-administration. The above differences may be caused by the hormonal (mainly estradiol) fluctuations that occur during the estrus cycle in intact females. Accordingly, in intact females CFB self-administration and dopamine activity were found to fluctuate across the estrus cycle, with lower parameters of CFB self-administration and lower dopamine activity in the Proestrus and Estrus phases vs. the Metestrus and Diestrus phases of the cycle.
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Affiliation(s)
- Andrea Contini
- Department of Biomedical Sciences, Section of Neuroscience and Clinical Pharmacology, SS 554, km 4,500, 09042 Monserrato, Cagliari, Italy.
| | - Fabrizio Sanna
- Department of Biomedical Sciences, Section of Neuroscience and Clinical Pharmacology, SS 554, km 4,500, 09042 Monserrato, Cagliari, Italy
| | - Paola Maccioni
- Neuroscience Institute, National Research Council of Italy, Section of Cagliari, SS 554, km 4,500, 09042 Monserrato, Cagliari, Italy
| | - Giancarlo Colombo
- Neuroscience Institute, National Research Council of Italy, Section of Cagliari, SS 554, km 4,500, 09042 Monserrato, Cagliari, Italy
| | - Antonio Argiolas
- Department of Biomedical Sciences, Section of Neuroscience and Clinical Pharmacology, SS 554, km 4,500, 09042 Monserrato, Cagliari, Italy; Neuroscience Institute, National Research Council of Italy, Section of Cagliari, SS 554, km 4,500, 09042 Monserrato, Cagliari, Italy
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24
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Tauber JM, Brown EB, Li Y, Yurgel ME, Masek P, Keene AC. A subset of sweet-sensing neurons identified by IR56d are necessary and sufficient for fatty acid taste. PLoS Genet 2017; 13:e1007059. [PMID: 29121639 PMCID: PMC5697886 DOI: 10.1371/journal.pgen.1007059] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2017] [Revised: 11/21/2017] [Accepted: 10/08/2017] [Indexed: 01/10/2023] Open
Abstract
Fat represents a calorically potent food source that yields approximately twice the amount of energy as carbohydrates or proteins per unit of mass. The highly palatable taste of free fatty acids (FAs), one of the building blocks of fat, promotes food consumption, activates reward circuitry, and is thought to contribute to hedonic feeding underlying many metabolism-related disorders. Despite a role in the etiology of metabolic diseases, little is known about how dietary fats are detected by the gustatory system to promote feeding. Previously, we showed that a broad population of sugar-sensing taste neurons expressing Gustatory Receptor 64f (Gr64f) is required for reflexive feeding responses to both FAs and sugars. Here, we report a genetic silencing screen to identify specific populations of taste neurons that mediate fatty acid (FA) taste. We find neurons identified by expression of Ionotropic Receptor 56d (IR56d) are necessary and sufficient for reflexive feeding response to FAs. Functional imaging reveals that IR56d-expressing neurons are responsive to short- and medium-chain FAs. Silencing IR56d neurons selectively abolishes FA taste, and their activation is sufficient to drive feeding responses. Analysis of co-expression with Gr64f identifies two subpopulations of IR56d-expressing neurons. While physiological imaging reveals that both populations are responsive to FAs, IR56d/Gr64f neurons are activated by medium-chain FAs and are sufficient for reflexive feeding response to FAs. Moreover, flies can discriminate between sugar and FAs in an aversive taste memory assay, indicating that FA taste is a unique modality in Drosophila. Taken together, these findings localize FA taste within the Drosophila gustatory center and provide an opportunity to investigate discrimination between different categories of appetitive tastants. Fat represents a calorically potent food source that yields approximately twice the amount of energy as carbohydrates or proteins per unit of mass. Dietary lipids are comprised of both triacylglycerides and FAs, and growing evidence suggests that it is the free FAs that are detected by the gustatory system. The highly palatable taste of FAs promotes food consumption, activates reward centers in mammals, and is thought to contribute to hedonic feeding that underlies many metabolism-related disorders. Despite a role in the etiology of metabolic diseases, little is known about how dietary fats are detected by the gustatory system to promote feeding. We have identified a subset of sugar-sensing neurons in the fly that also responds to medium-chain FAs and are necessary and sufficient for behavioral response to FAs. Further, we find that despite being sensed by shared neuronal populations, flies can differentiate between the taste of sugar and FAs, fortifying the notion that FAs and sugar represent distinct taste modalities in flies.
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Affiliation(s)
- John M. Tauber
- Department of Biological Sciences, Florida Atlantic University, Jupiter, FL, United States of America
| | - Elizabeth B. Brown
- Department of Biological Sciences, Florida Atlantic University, Jupiter, FL, United States of America
| | - Yuanyuan Li
- Department of Biological Sciences, Binghamton University, Binghamton, NY, United States of America
| | - Maria E. Yurgel
- Department of Biological Sciences, Florida Atlantic University, Jupiter, FL, United States of America
| | - Pavel Masek
- Department of Biological Sciences, Binghamton University, Binghamton, NY, United States of America
| | - Alex C. Keene
- Department of Biological Sciences, Florida Atlantic University, Jupiter, FL, United States of America
- * E-mail:
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Barson JR, Leibowitz SF. Orexin/Hypocretin System: Role in Food and Drug Overconsumption. INTERNATIONAL REVIEW OF NEUROBIOLOGY 2017; 136:199-237. [PMID: 29056152 DOI: 10.1016/bs.irn.2017.06.006] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The neuropeptide orexin/hypocretin (OX), while largely transcribed within the hypothalamus, is released throughout the brain to affect complex behaviors. Primarily through the hypothalamus itself, OX homeostatically regulates adaptive behaviors needed for survival, including food intake, sleep-wake regulation, mating, and maternal behavior. However, through extrahypothalamic limbic brain regions, OX promotes seeking and intake of rewarding substances of abuse, like palatable food, alcohol, nicotine, and cocaine. This neuropeptide, in turn, is stimulated by the intake of or early life exposure to these substances, forming a nonhomeostatic, positive feedback loop. The specific OX receptor involved in these behaviors, whether adaptive behavior or substance seeking and intake, is dependent on the particular brain region that contributes to them. Thus, we propose that, while the primary function of OX is to maintain arousal for the performance of adaptive behaviors, this neuropeptide system is readily co-opted by rewarding substances that involve positive feedback, ultimately promoting their abuse.
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Affiliation(s)
- Jessica R Barson
- Drexel University College of Medicine, Philadelphia, PA, United States
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Corwin RLW, Wojnicki FHE, Zimmer DJ, Babbs RK, McGrath LE, Olivos DR, Mietlicki-Baase EG, Hayes MR. Binge-type eating disrupts dopaminergic and GABAergic signaling in the prefrontal cortex and ventral tegmental area. Obesity (Silver Spring) 2016; 24:2118-25. [PMID: 27558648 DOI: 10.1002/oby.21626] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/05/2016] [Revised: 06/14/2016] [Accepted: 06/17/2016] [Indexed: 01/22/2023]
Abstract
OBJECTIVE Binge eating is characterized by repeated intermittent bouts of compulsive overconsumption of food. Treatment is challenging given limited understanding of the mechanisms underlying this type of disordered eating. The hypothesis that dysregulation of mesocortical dopaminergic and GABAergic systems underlie binge eating was tested. METHODS Analysis of gene expression within the ventral tegmental area and its terminal mesocortical regions was examined in bingeing rats before and after bingeing occurred. In addition, alterations in binge-type behavior induced by pharmacological inactivation of subnuclei of the prefrontal cortex (PFC) and by pharmacological activation and inhibition of cortical D1 and D2 receptors were examined. RESULTS Correlative and functional evidence demonstrates dysregulated neurotransmitter processing by the PFC and ventral tegmental area, but not the amygdala or nucleus accumbens, in bingeing rats. Either GABAergic inactivation or D2-like receptor activation within the PFC increased consumption in bingeing rats, but not controls, suggesting that the PFC, and D2 receptors in particular, functions as a behavioral brake to limit bingeing. CONCLUSIONS The act of bingeing resolved some gene expression differences that preceded binge onset, further suggesting that bingeing may partially serve to self-medicate a system driving this maladaptive behavior. However, the failure of bingeing to resolve other dopaminergic/GABAergic differences may render individuals vulnerable to future binge episodes.
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Affiliation(s)
- Rebecca L W Corwin
- Nutritional Sciences Department, College of Health and Human Development, The Pennsylvania State University, University Park, Pennsylvania, USA.
| | - Francis H E Wojnicki
- Nutritional Sciences Department, College of Health and Human Development, The Pennsylvania State University, University Park, Pennsylvania, USA
| | - Derek J Zimmer
- Department of Psychiatry, Translational Neuroscience Program, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - R Keith Babbs
- Nutritional Sciences Department, College of Health and Human Development, The Pennsylvania State University, University Park, Pennsylvania, USA
| | - Lauren E McGrath
- Department of Psychiatry, Translational Neuroscience Program, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Diana R Olivos
- Department of Psychiatry, Translational Neuroscience Program, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Elizabeth G Mietlicki-Baase
- Department of Psychiatry, Translational Neuroscience Program, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Matthew R Hayes
- Department of Psychiatry, Translational Neuroscience Program, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania, USA
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Franco R, Fonoff ET, Alvarenga P, Lopes AC, Miguel EC, Teixeira MJ, Damiani D, Hamani C. DBS for Obesity. Brain Sci 2016; 6:brainsci6030021. [PMID: 27438859 PMCID: PMC5039450 DOI: 10.3390/brainsci6030021] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2016] [Revised: 07/09/2016] [Accepted: 07/12/2016] [Indexed: 12/11/2022] Open
Abstract
Obesity is a chronic, progressive and prevalent disorder. Morbid obesity, in particular, is associated with numerous comorbidities and early mortality. In patients with morbid obesity, pharmacological and behavioral approaches often have limited results. Bariatric surgery is quite effective but is associated with operative failures and a non-negligible incidence of side effects. In the last decades, deep brain stimulation (DBS) has been investigated as a neurosurgical modality to treat various neuropsychiatric disorders. In this article we review the rationale for selecting different brain targets, surgical results and future perspectives for the use of DBS in medically refractory obesity.
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Affiliation(s)
- Ruth Franco
- Division of Pediatric Endocrinology, Children's Hospital, University of São Paulo Medical School, São Paulo 05403-000, Brazil.
| | - Erich T Fonoff
- Division of Functional Neurosurgery of Institute of Psychiatry, Department of Neurology, University of São Paulo Medical School, São Paulo 01060-970, Brazil.
| | - Pedro Alvarenga
- Department of Psychiatry, Institute of Psychiatry, University of São Paulo Medical School, São Paulo 01060-970, Brazil.
| | - Antonio Carlos Lopes
- Department of Psychiatry, Institute of Psychiatry, University of São Paulo Medical School, São Paulo 01060-970, Brazil.
| | - Euripides C Miguel
- Department of Psychiatry, Institute of Psychiatry, University of São Paulo Medical School, São Paulo 01060-970, Brazil.
| | - Manoel J Teixeira
- Division of Functional Neurosurgery of Institute of Psychiatry, Department of Neurology, University of São Paulo Medical School, São Paulo 01060-970, Brazil.
| | - Durval Damiani
- Division of Pediatric Endocrinology, Children's Hospital, University of São Paulo Medical School, São Paulo 05403-000, Brazil.
| | - Clement Hamani
- Division of Functional Neurosurgery of Institute of Psychiatry, Department of Neurology, University of São Paulo Medical School, São Paulo 01060-970, Brazil.
- Division of Neurosurgery, Toronto Western Hospital, University of Toronto, Toronto, ON M5T 1R8, Canada.
- Division of Neuroimaging, Centre for Addiction and Mental Health, Toronto, ON M5T 1R8, Canada.
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Berland C, Cansell C, Hnasko TS, Magnan C, Luquet S. Dietary triglycerides as signaling molecules that influence reward and motivation. Curr Opin Behav Sci 2016; 9:126-135. [PMID: 28191490 DOI: 10.1016/j.cobeha.2016.03.005] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The reinforcing and motivational aspects of food are tied to the release of the dopamine in the mesolimbic system (ML). Free fatty acids from triglyceride (TG)-rich particles are released upon action of TG-lipases found at high levels in peripheral oxidative tissue (muscle, heart), but also in the ML. This suggests that local TG-hydrolysis in the ML might regulate food seeking and reward. Indeed, evidence now suggests that dietary TG directly target the ML to regulate amphetamine-induced locomotion and reward seeking behavior. Though the cellular mechanisms of TG action are unresolved, TG act in part through ML lipoprotein lipase, upstream of dopamine 2 receptor (D2R), and show desensitization in conditions of chronically elevated plasma TG as occur in obesity. TG sensing in the ML therefore represents a new mechanism by which chronic consumption of dietary fat might lead to adaptations in the ML and dysregulated feeding behaviors.
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Affiliation(s)
- Chloé Berland
- Univ Paris Diderot, Sorbonne Paris Cité, Unité de Biologie Fonctionnelle et Adaptative, CNRS UMR 8251, F-75205 Paris, France; Helmholtz Diabetes Center, Helmholtz Zentrum München, German Research Center for Environmental Health, München/Neuherberg, Germany; Div. of Metabolic Diseases, Dept. of Medicine, Technische Universität München, Germany
| | - Céline Cansell
- Université de Nice Sophia Antipolis, IPMC, Sophia Antipolis, F-06560, France; CNRS, IPMC, Sophia Antipolis, F-06560, France
| | - Thomas S Hnasko
- Department of Neurosciences, University of California, San Diego, La Jolla CA, USA
| | - Christophe Magnan
- Univ Paris Diderot, Sorbonne Paris Cité, Unité de Biologie Fonctionnelle et Adaptative, CNRS UMR 8251, F-75205 Paris, France
| | - Serge Luquet
- Univ Paris Diderot, Sorbonne Paris Cité, Unité de Biologie Fonctionnelle et Adaptative, CNRS UMR 8251, F-75205 Paris, France
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30
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Burke MV, Small DM. Effects of the modern food environment on striatal function, cognition and regulation of ingestive behavior. Curr Opin Behav Sci 2016; 9:97-105. [PMID: 29619405 DOI: 10.1016/j.cobeha.2016.02.036] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Emerging evidence from human and animal studies suggest that consumption of palatable foods rich in fat and/or carbohydrates may produce deleterious influences on brain function independently of body weight or metabolic disease. Here we consider two mechanisms by which diet can impact striatal circuits to amplify food cue reactivity and impair inhibitory control. First, we review findings demonstrating that the energetic properties of foods regulate nucleus accumbens food cue reactivity, a demonstrated predictor of weight gain susceptibility, which is then sensitized by chronic consumption of an energy dense diet. Second, we consider evidence for diet-induced adaptations in dorsal striatal dopamine signaling that is associated with impaired inhibitory control and negative outcome learning.
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Affiliation(s)
- Mary V Burke
- Interdepartmental Neuroscience Program, Yale University, New Haven, CT, U.S.,John B. Pierce Laboratory, 290 Congress Avenue, New Haven, CT, U.S.,Modern Diet and Physiology Research Center, 290 Congress Avenue, New Haven, CT, U.S
| | - Dana M Small
- Interdepartmental Neuroscience Program, Yale University, New Haven, CT, U.S.,John B. Pierce Laboratory, 290 Congress Avenue, New Haven, CT, U.S.,Department of Psychiatry, Yale School of Medicine, New Haven, CT, U.S.,Department of Psychology, Yale University, New Haven, CT, U.S.,Modern Diet and Physiology Research Center, 290 Congress Avenue, New Haven, CT, U.S
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Ikeda H, Ardianto C, Yonemochi N, Yang L, Ohashi T, Ikegami M, Nagase H, Kamei J. Inhibition of opioid systems in the hypothalamus as well as the mesolimbic area suppresses feeding behavior of mice. Neuroscience 2015; 311:9-21. [PMID: 26454026 DOI: 10.1016/j.neuroscience.2015.10.002] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2015] [Revised: 09/29/2015] [Accepted: 10/02/2015] [Indexed: 12/23/2022]
Abstract
Opioid receptors, especially μ-opioid receptors, in the ventral tegmental area (VTA) and nucleus accumbens (NAcc) are reported to regulate food motivation. However, the roles of μ-, δ- and κ-opioid receptors are not fully understood. Moreover, since μ-, δ- and κ-opioid receptors are reported to distribute in the hypothalamus, these receptors in the hypothalamus might regulate feeding behavior. Thus, the present study investigated the role of μ-, δ- and κ-opioid receptors in the VTA, the NAcc and the hypothalamus in the regulation of feeding behavior. Male ICR mice were subjected to a feeding test after food deprivation for 16h. The mRNA levels of proopiomelanocortin (POMC), preproenkephalin (PENK) and prodynorphin (PDYN), the precursors of endogenous opioid peptides, were measured by reverse transcription-polymerase chain reaction (RT-PCR). The systemic injection of non-selective (naloxone) and selective μ (β-funaltrexamine; β-FNA), δ (naltrindole) and κ (norbinaltorphimine; norBNI) opioid receptor antagonists markedly reduced food intake. In contrast, the systemic injection of preferential μ (morphine), selective δ (KNT-127) and κ (U-50,488) opioid receptor agonists did not change food intake. The mRNA levels of POMC, PENK and PDYN were decreased in the hypothalamus and the midbrain after food deprivation, whereas the mRNA levels of PENK and PDYN, but not POMC, were decreased in the ventral striatum. The injection of naloxone into the NAcc, VTA and lateral hypothalamus (LH), but not the ventromedial nucleus of the hypothalamus, significantly decreased food intake. The injection of β-FNA and naltrindole into the LH, but not the VTA or NAcc, decreased food intake. The injection of norBNI into the LH and VTA, but not the NAcc, decreased food intake. These results indicate that μ-, δ- and κ-opioid receptors in the LH play a more important role in the regulation of feeding behavior than those receptors in the VTA and the NAcc.
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Affiliation(s)
- H Ikeda
- Department of Pathophysiology and Therapeutics, Hoshi University School of Pharmacy and Pharmaceutical Sciences, 2-4-41 Ebara, Shinagawa-ku, Tokyo 142-8501, Japan.
| | - C Ardianto
- Department of Pathophysiology and Therapeutics, Hoshi University School of Pharmacy and Pharmaceutical Sciences, 2-4-41 Ebara, Shinagawa-ku, Tokyo 142-8501, Japan
| | - N Yonemochi
- Department of Pathophysiology and Therapeutics, Hoshi University School of Pharmacy and Pharmaceutical Sciences, 2-4-41 Ebara, Shinagawa-ku, Tokyo 142-8501, Japan
| | - L Yang
- Department of Pathophysiology and Therapeutics, Hoshi University School of Pharmacy and Pharmaceutical Sciences, 2-4-41 Ebara, Shinagawa-ku, Tokyo 142-8501, Japan
| | - T Ohashi
- Department of Pathophysiology and Therapeutics, Hoshi University School of Pharmacy and Pharmaceutical Sciences, 2-4-41 Ebara, Shinagawa-ku, Tokyo 142-8501, Japan
| | - M Ikegami
- Department of Pathophysiology and Therapeutics, Hoshi University School of Pharmacy and Pharmaceutical Sciences, 2-4-41 Ebara, Shinagawa-ku, Tokyo 142-8501, Japan
| | - H Nagase
- International Institute for Integrative Sleep Medicine (WPI-IIIS), University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8575, Japan
| | - J Kamei
- Department of Pathophysiology and Therapeutics, Hoshi University School of Pharmacy and Pharmaceutical Sciences, 2-4-41 Ebara, Shinagawa-ku, Tokyo 142-8501, Japan
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Tulloch AJ, Murray S, Vaicekonyte R, Avena NM. Neural responses to macronutrients: hedonic and homeostatic mechanisms. Gastroenterology 2015; 148:1205-18. [PMID: 25644095 DOI: 10.1053/j.gastro.2014.12.058] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/06/2014] [Revised: 12/16/2014] [Accepted: 12/22/2014] [Indexed: 01/15/2023]
Abstract
The brain responds to macronutrients via intricate mechanisms. We review how the brain's neural systems implicated in homeostatic control of feeding and hedonic responses are influenced by the ingestion of specific types of food. We discuss how these neural systems are dysregulated in preclinical models of obesity. Findings from these studies can increase our understanding of overeating and, perhaps in some cases, the development of obesity. In addition, a greater understanding of the neural circuits affected by the consumption of specific macronutrients, and by obesity, might lead to new treatments and strategies for preventing unhealthy weight gain.
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Affiliation(s)
- Alastair J Tulloch
- Department of Pharmacology and Systems Therapeutics, Mount Sinai School of Medicine, New York, New York
| | - Susan Murray
- Department of Pharmacology and Systems Therapeutics, Mount Sinai School of Medicine, New York, New York
| | - Regina Vaicekonyte
- Department of Pharmacology and Systems Therapeutics, Mount Sinai School of Medicine, New York, New York
| | - Nicole M Avena
- Department of Pharmacology and Systems Therapeutics, Mount Sinai School of Medicine, New York, New York.
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Common effects of fat, ethanol, and nicotine on enkephalin in discrete areas of the brain. Neuroscience 2014; 277:665-78. [PMID: 25086310 DOI: 10.1016/j.neuroscience.2014.07.050] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2014] [Revised: 07/09/2014] [Accepted: 07/14/2014] [Indexed: 01/27/2023]
Abstract
Fat, ethanol, and nicotine share a number of properties, including their ability to reinforce behavior and produce overconsumption. To test whether these substances act similarly on the same neuronal populations in specific brain areas mediating these behaviors, we administered the substances short-term, using the same methods and within the same experiment, and measured their effects, in areas of the hypothalamus (HYPO), amygdala (AMYG), and nucleus accumbens (NAc), on mRNA levels of the opioid peptide, enkephalin (ENK), using in situ hybridization and on c-Fos immunoreactivity (ir) to indicate neuronal activity, using immunofluorescence histochemistry. In addition, we examined for comparison another reinforcing substance, sucrose, and also took measurements of stress-related behaviors and circulating corticosterone (CORT) and triglycerides (TG), to determine if they contribute to these substances' behavioral and physiological effects. Adult Sprague-Dawley rats were gavaged three times daily over 5 days with 3.5 mL of water, Intralipid (20% v/v), ethanol (12% v/v), nicotine (0.01% w/v) or sucrose (22% w/v) (approximately 7 kcal/dose), and tail vein blood was collected for measurements of circulating CORT and TG. On day five, animals were sacrificed, brains removed, and the HYPO, AMYG, and NAc processed for single- or double-labeling of ENK mRNA and c-Fos-ir. Fat, ethanol, and nicotine, but not sucrose, increased the single- and double-labeling of ENK and c-Fos-ir in precisely the same brain areas, the middle parvocellular but not lateral area of the paraventricular nucleus, central but not basolateral nucleus of the AMYG, and core but not shell of the NAc. While having little effect on stress-related behaviors or CORT levels, fat, ethanol, and nicotine all increased circulating levels of TG. These findings suggest that the overconsumption of these three substances and their potential for abuse are mediated by the same populations of ENK-expressing neurons in specific nuclei of the hypothalamus and limbic system.
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