1
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Chesters RA, Zhu J, Coull BM, Baidoe-Ansah D, Baumer L, Palm L, Klinghammer N, Chen S, Hahm A, Yagoub S, Cantacorps L, Bernardi D, Ritter K, Lippert RN. Fasting-induced activity changes in MC3R neurons of the paraventricular nucleus of the thalamus. Life Sci Alliance 2024; 7:e202402754. [PMID: 39107065 PMCID: PMC11303869 DOI: 10.26508/lsa.202402754] [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: 04/04/2024] [Revised: 07/26/2024] [Accepted: 07/29/2024] [Indexed: 08/09/2024] Open
Abstract
The brain controls energy homeostasis by regulating food intake through signaling within the melanocortin system. Whilst we understand the role of the hypothalamus within this system, how extra-hypothalamic brain regions are involved in controlling energy balance remains unclear. Here we show that the melanocortin 3 receptor (MC3R) is expressed in the paraventricular nucleus of the thalamus (PVT). We tested whether fasting would change the activity of MC3R neurons in this region by assessing the levels of c-Fos and pCREB as neuronal activity markers. We determined that overnight fasting causes a significant reduction in pCREB levels within PVT-MC3R neurons. We then questioned whether perturbation of MC3R signaling, during fasting, would result in altered refeeding. Using chemogenetic approaches, we show that modulation of MC3R activity, during the fasting period, does not impact body weight regain or total food intake in the refeeding period. However, we did observe significant differences in the pattern of feeding-related behavior. These findings suggest that the PVT is a region where MC3R neurons respond to energy deprivation and modulate refeeding behavior.
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Affiliation(s)
- Robert A Chesters
- Department of Neurocircuit Development and Function, German Institute of Human Nutrition https://ror.org/05xdczy51, Nuthetal, Germany
| | - Jiajie Zhu
- Department of Neurocircuit Development and Function, German Institute of Human Nutrition https://ror.org/05xdczy51, Nuthetal, Germany
- NeuroCure Cluster of Excellence, Charité-Universitätsmedizin, Berlin, Germany
| | - Bethany M Coull
- Department of Neurocircuit Development and Function, German Institute of Human Nutrition https://ror.org/05xdczy51, Nuthetal, Germany
- NeuroCure Cluster of Excellence, Charité-Universitätsmedizin, Berlin, Germany
| | - David Baidoe-Ansah
- Department of Neurocircuit Development and Function, German Institute of Human Nutrition https://ror.org/05xdczy51, Nuthetal, Germany
- NeuroCure Cluster of Excellence, Charité-Universitätsmedizin, Berlin, Germany
| | - Lea Baumer
- Department of Neurocircuit Development and Function, German Institute of Human Nutrition https://ror.org/05xdczy51, Nuthetal, Germany
| | - Lydia Palm
- Department of Neurocircuit Development and Function, German Institute of Human Nutrition https://ror.org/05xdczy51, Nuthetal, Germany
| | - Niklas Klinghammer
- Department of Neurocircuit Development and Function, German Institute of Human Nutrition https://ror.org/05xdczy51, Nuthetal, Germany
| | - Seve Chen
- Department of Neurocircuit Development and Function, German Institute of Human Nutrition https://ror.org/05xdczy51, Nuthetal, Germany
| | - Anneke Hahm
- Department of Neurocircuit Development and Function, German Institute of Human Nutrition https://ror.org/05xdczy51, Nuthetal, Germany
| | - Selma Yagoub
- Department of Neurocircuit Development and Function, German Institute of Human Nutrition https://ror.org/05xdczy51, Nuthetal, Germany
| | - Lídia Cantacorps
- Department of Neurocircuit Development and Function, German Institute of Human Nutrition https://ror.org/05xdczy51, Nuthetal, Germany
- German Center for Diabetes Research (DZD), München-Neuherberg, Germany
| | - Daniel Bernardi
- Department of Neurocircuit Development and Function, German Institute of Human Nutrition https://ror.org/05xdczy51, Nuthetal, Germany
| | - Katrin Ritter
- Department of Neurocircuit Development and Function, German Institute of Human Nutrition https://ror.org/05xdczy51, Nuthetal, Germany
| | - Rachel N Lippert
- Department of Neurocircuit Development and Function, German Institute of Human Nutrition https://ror.org/05xdczy51, Nuthetal, Germany
- German Center for Diabetes Research (DZD), München-Neuherberg, Germany
- NeuroCure Cluster of Excellence, Charité-Universitätsmedizin, Berlin, Germany
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2
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Cai H, Schnapp WI, Mann S, Miscevic M, Shcmit MB, Conteras M, Fang C. Neural circuits regulation of satiation. Appetite 2024; 200:107512. [PMID: 38801994 PMCID: PMC11227400 DOI: 10.1016/j.appet.2024.107512] [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: 02/05/2024] [Revised: 05/21/2024] [Accepted: 05/22/2024] [Indexed: 05/29/2024]
Abstract
Terminating a meal after achieving satiation is a critical step in maintaining a healthy energy balance. Despite the extensive collection of information over the last few decades regarding the neural mechanisms controlling overall eating, the mechanism underlying different temporal phases of eating behaviors, especially satiation, remains incompletely understood and is typically embedded in studies that measure the total amount of food intake. In this review, we summarize the neural circuits that detect and integrate satiation signals to suppress appetite, from interoceptive sensory inputs to the final motor outputs. Due to the well-established role of cholecystokinin (CCK) in regulating the satiation, we focus on the neural circuits that are involved in regulating the satiation effect caused by CCK. We also discuss several general principles of how these neural circuits control satiation, as well as the limitations of our current understanding of the circuits function. With the application of new techniques involving sophisticated cell-type-specific manipulation and mapping, as well as real-time recordings, it is now possible to gain a better understanding of the mechanisms specifically underlying satiation.
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Affiliation(s)
- Haijiang Cai
- Department of Neuroscience, University of Arizona, Tucson, AZ, 85721, USA; Bio 5 Institute and Department of Neurology, University of Arizona, Tucson, AZ, 85721, USA.
| | - Wesley I Schnapp
- Department of Neuroscience, University of Arizona, Tucson, AZ, 85721, USA; Graduate Interdisciplinary Program in Neuroscience, University of Arizona, Tucson, AZ, 85721, USA
| | - Shivani Mann
- Department of Neuroscience, University of Arizona, Tucson, AZ, 85721, USA
| | - Masa Miscevic
- Department of Neuroscience, University of Arizona, Tucson, AZ, 85721, USA; Graduate Interdisciplinary Program in Physiological Sciences, University of Arizona, Tucson, AZ, 85721, USA
| | - Matthew B Shcmit
- Department of Neuroscience, University of Arizona, Tucson, AZ, 85721, USA; Graduate Interdisciplinary Program in Neuroscience, University of Arizona, Tucson, AZ, 85721, USA
| | - Marco Conteras
- Department of Neuroscience, University of Arizona, Tucson, AZ, 85721, USA
| | - Caohui Fang
- Department of Neuroscience, University of Arizona, Tucson, AZ, 85721, USA
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3
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Magkos F, Sørensen TIA, Raubenheimer D, Dhurandhar NV, Loos RJF, Bosy-Westphal A, Clemmensen C, Hjorth MF, Allison DB, Taubes G, Ravussin E, Friedman MI, Hall KD, Ludwig DS, Speakman JR, Astrup A. On the pathogenesis of obesity: causal models and missing pieces of the puzzle. Nat Metab 2024:10.1038/s42255-024-01106-8. [PMID: 39164418 DOI: 10.1038/s42255-024-01106-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/03/2024] [Accepted: 07/10/2024] [Indexed: 08/22/2024]
Abstract
Application of the physical laws of energy and mass conservation at the whole-body level is not necessarily informative about causal mechanisms of weight gain and the development of obesity. The energy balance model (EBM) and the carbohydrate-insulin model (CIM) are two plausible theories, among several others, attempting to explain why obesity develops within an overall common physiological framework of regulation of human energy metabolism. These models have been used to explain the pathogenesis of obesity in individuals as well as the dramatic increases in the prevalence of obesity worldwide over the past half century. Here, we summarize outcomes of a recent workshop in Copenhagen that brought together obesity experts from around the world to discuss causal models of obesity pathogenesis. These discussions helped to operationally define commonly used terms; delineate the structure of each model, particularly focussing on areas of overlap and divergence; challenge ideas about the importance of purported causal factors for weight gain; and brainstorm on the key scientific questions that need to be answered. We hope that more experimental research in nutrition and other related fields, and more testing of the models and their predictions will pave the way and provide more answers about the pathogenesis of obesity than those currently available.
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Affiliation(s)
- Faidon Magkos
- Department of Nutrition, Exercise and Sports, University of Copenhagen, Frederiksberg, Denmark.
| | - Thorkild I A Sørensen
- Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
- Department of Public Health, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
- Center for Childhood Health, Copenhagen, Denmark
| | - David Raubenheimer
- Charles Perkins Centre and School of Life and Environmental Sciences, the University of Sydney, Sydney, New South Wales, Australia
| | | | - Ruth J F Loos
- Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Anja Bosy-Westphal
- Institute of Human Nutrition and Food Science, Kiel University, Kiel, Germany
| | - Christoffer Clemmensen
- Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Mads F Hjorth
- Department of Obesity and Nutritional Sciences, Novo Nordisk Foundation, Hellerup, Denmark
| | - David B Allison
- School of Public Health, Indiana University Bloomington, Bloomington, IN, USA
| | | | - Eric Ravussin
- Pennington Biomedical Research Center, Louisiana State University, Baton Rouge, LA, USA
| | | | - Kevin D Hall
- National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, MD, USA
| | - David S Ludwig
- New Balance Foundation Obesity Prevention Center, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
- Department of Nutrition, Exercise and Sports, University of Copenhagen, Copenhagen, Denmark
| | - John R Speakman
- Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China
- University of Aberdeen, Aberdeen, UK
| | - Arne Astrup
- Department of Obesity and Nutritional Sciences, Novo Nordisk Foundation, Hellerup, Denmark
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4
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Hoisington ZW, Salvi A, Laguesse S, Ehinger Y, Shukla C, Phamluong K, Ron D. The Small G-Protein Rac1 in the Dorsomedial Striatum Promotes Alcohol-Dependent Structural Plasticity and Goal-Directed Learning in Mice. J Neurosci 2024; 44:e1644232024. [PMID: 38886056 PMCID: PMC11255432 DOI: 10.1523/jneurosci.1644-23.2024] [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: 08/28/2023] [Revised: 04/04/2024] [Accepted: 04/10/2024] [Indexed: 06/20/2024] Open
Abstract
The small G-protein Ras-related C3 botulinum toxin substrate 1 (Rac1) promotes the formation of filamentous actin (F-actin). Actin is a major component of dendritic spines, and we previously found that alcohol alters actin composition and dendritic spine structure in the nucleus accumbens (NAc) and the dorsomedial striatum (DMS). To examine if Rac1 contributes to these alcohol-mediated adaptations, we measured the level of GTP-bound active Rac1 in the striatum of mice following 7 weeks of intermittent access to 20% alcohol. We found that chronic alcohol intake activates Rac1 in the DMS of male mice. In contrast, Rac1 is not activated by alcohol in the NAc and DLS of male mice or in the DMS of female mice. Similarly, closely related small G-proteins are not activated by alcohol in the DMS, and Rac1 activity is not increased in the DMS by moderate alcohol or natural reward. To determine the consequences of alcohol-dependent Rac1 activation in the DMS of male mice, we inhibited endogenous Rac1 by infecting the DMS of mice with an adeno-associated virus (AAV) expressing a dominant negative form of the small G-protein (Rac1-DN). We found that overexpression of AAV-Rac1-DN in the DMS inhibits alcohol-mediated Rac1 signaling and attenuates alcohol-mediated F-actin polymerization, which corresponded with a decrease in dendritic arborization and spine maturation. Finally, we provide evidence to suggest that Rac1 in the DMS plays a role in alcohol-associated goal-directed learning. Together, our data suggest that Rac1 in the DMS plays an important role in alcohol-dependent structural plasticity and aberrant learning.
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Affiliation(s)
- Zachary W Hoisington
- Alcohol and Addiction Research Group, Department of Neurology, University of California San Francisco, San Francisco, California 94107
| | - Alexandra Salvi
- Alcohol and Addiction Research Group, Department of Neurology, University of California San Francisco, San Francisco, California 94107
| | - Sophie Laguesse
- GIGA-Stem Cells and GIGA-Neurosciences, Interdisciplinary Cluster for Applied Genoproteomics (GIGA-R), University of Liège, Liège 4000, Belgium
| | - Yann Ehinger
- Alcohol and Addiction Research Group, Department of Neurology, University of California San Francisco, San Francisco, California 94107
| | - Chhavi Shukla
- Alcohol and Addiction Research Group, Department of Neurology, University of California San Francisco, San Francisco, California 94107
| | - Khanhky Phamluong
- Alcohol and Addiction Research Group, Department of Neurology, University of California San Francisco, San Francisco, California 94107
| | - Dorit Ron
- Alcohol and Addiction Research Group, Department of Neurology, University of California San Francisco, San Francisco, California 94107
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5
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Vargas Y, Castro Tron AE, Rodríguez Rodríguez A, Uribe RM, Joseph-Bravo P, Charli JL. Thyrotropin-Releasing Hormone and Food Intake in Mammals: An Update. Metabolites 2024; 14:302. [PMID: 38921437 PMCID: PMC11205479 DOI: 10.3390/metabo14060302] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2024] [Revised: 05/23/2024] [Accepted: 05/23/2024] [Indexed: 06/27/2024] Open
Abstract
Thyrotropin-releasing hormone (TRH; pGlu-His-Pro-NH2) is an intercellular signal produced mainly by neurons. Among the multiple pharmacological effects of TRH, that on food intake is not well understood. We review studies demonstrating that peripheral injection of TRH generally produces a transient anorexic effect, discuss the pathways that might initiate this effect, and explain its short half-life. In addition, central administration of TRH can produce anorexic or orexigenic effects, depending on the site of injection, that are likely due to interaction with TRH receptor 1. Anorexic effects are most notable when TRH is injected into the hypothalamus and the nucleus accumbens, while the orexigenic effect has only been detected by injection into the brain stem. Functional evidence points to TRH neurons that are prime candidate vectors for TRH action on food intake. These include the caudal raphe nuclei projecting to the dorsal motor nucleus of the vagus, and possibly TRH neurons from the tuberal lateral hypothalamus projecting to the tuberomammillary nuclei. For other TRH neurons, the anatomical or physiological context and impact of TRH in each synaptic domain are still poorly understood. The manipulation of TRH expression in well-defined neuron types will facilitate the discovery of its role in food intake control in each anatomical scene.
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Affiliation(s)
| | | | | | | | | | - Jean-Louis Charli
- Departamento de Genética del Desarrollo y Fisiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México (UNAM), Avenida Universidad 2001, Cuernavaca 62210, Mexico; (Y.V.); (A.E.C.T.); (A.R.R.); (R.M.U.); (P.J.-B.)
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6
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Konanur VR, Hurh SJ, Hsu TM, Roitman MF. Dopamine neuron activity evoked by sucrose and sucrose-predictive cues is augmented by peripheral and central manipulations of glucose availability. Eur J Neurosci 2024; 59:2419-2435. [PMID: 38057909 PMCID: PMC11108752 DOI: 10.1111/ejn.16214] [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: 05/24/2023] [Revised: 10/23/2023] [Accepted: 11/16/2023] [Indexed: 12/08/2023]
Abstract
Food deprivation drives eating through multiple signals and circuits. Decreased glucose availability (i.e., cytoglucopenia) drives eating and also increases the value of sucrose. Ventral tegmental area (VTA) dopamine neurons (DANs) contribute to the evaluation of taste stimuli, but their role in integrating glucoprivic signals remains unknown. We monitored VTA DAN activity via Cre-dependent expression of a calcium indicator with in vivo fibre photometry. In ad libitum fed rats, intraoral sucrose evoked a phasic increase in DAN activity. To manipulate glucose availability, we administered (intraperitoneal, lateral or fourth ventricular) the antiglycolytic agent 5-thio-D-glucose (5TG), which significantly augmented the phasic DAN activity to sucrose. 5TG failed to alter DAN activity to water or saccharin, suggesting the response was selective for caloric stimuli. 5TG enhancement of sucrose-evoked DAN activity was stronger after fourth ventricular administration, suggesting a critical node of action within the hindbrain. As 5TG also increases blood glucose, in a separate study, we used peripheral insulin, which stimulates eating, to decrease blood glucose-which was associated with increased DAN activity to intraoral sucrose. DAN activity developed to a cue predictive of intraoral sucrose. While 5TG augmented cue-evoked DAN activity, its action was most potent when delivered to the lateral ventricle. Together, the studies point to central glucose availability as a key modulator of phasic DAN activity to food and food-cues. As glucose sensing neurons are known to populate the hypothalamus and brainstem, results suggest differential modulation of cue-evoked and sucrose-evoked DAN activity.
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Affiliation(s)
- Vaibhav R. Konanur
- Department of Psychology, University of Illinois at Chicago, Chicago, IL
- Current affiliation: Department of Biology, University of Illinois at Chicago, Chicago, IL
| | - Samantha J. Hurh
- Department of Psychology, University of Illinois at Chicago, Chicago, IL
| | - Ted M. Hsu
- Department of Psychology, University of Illinois at Chicago, Chicago, IL
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7
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Reichenbach A, Dempsey H, Andrews ZB. Metabolic sensing in AgRP regulates sucrose preference and dopamine release in the nucleus accumbens. J Neuroendocrinol 2024; 36:e13389. [PMID: 38599683 DOI: 10.1111/jne.13389] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/28/2023] [Revised: 03/18/2024] [Accepted: 03/26/2024] [Indexed: 04/12/2024]
Abstract
Hunger increases the motivation for calorie consumption, often at the expense of low-taste appeal. However, the neural mechanisms integrating calorie-sensing with increased motivation for calorie consumption remain unknown. Agouti-related peptide (AgRP) neurons in the arcuate nucleus of the hypothalamus sense hunger, and the ingestion of caloric solutions promotes dopamine release in the absence of sweet taste perception. Therefore, we hypothesised that metabolic-sensing of hunger by AgRP neurons would be essential to promote dopamine release in the nucleus accumbens in response to caloric, but not non-caloric solutions. Moreover, we examined whether metabolic sensing in AgRP neurons affected taste preference for bitter solutions under conditions of energy need. Here we show that impaired metabolic sensing in AgRP neurons attenuated nucleus accumbens dopamine release in response to sucrose, but not saccharin, consumption. Furthermore, metabolic sensing in AgRP neurons was essential to distinguish nucleus accumbens dopamine response to sucrose consumption when compared with saccharin. Under conditions of hunger, metabolic sensing in AgRP neurons increased the preference for sucrose solutions laced with the bitter tastant, quinine, to ensure calorie consumption, whereas mice with impaired metabolic sensing in AgRP neurons maintained a strong aversion to sucrose/quinine solutions despite ongoing hunger. In conclusion, we demonstrate normal metabolic sensing in AgRP neurons drives the preference for calorie consumption, primarily when needed, by engaging dopamine release in the nucleus accumbens.
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Affiliation(s)
- Alex Reichenbach
- Monash Biomedicine Discovery Institute and Department of Physiology, Monash University, Clayton, Victoria, Australia
| | - Harry Dempsey
- Florey Institute of Neuroscience & Mental Health, Parkville, Victoria, Australia
| | - Zane B Andrews
- Monash Biomedicine Discovery Institute and Department of Physiology, Monash University, Clayton, Victoria, Australia
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8
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Hoisington ZW, Salvi A, Laguesse S, Ehinger Y, Shukla C, Phamluong K, Ron D. The small G-protein Rac1 in the dorsomedial striatum promotes alcohol-dependent structural plasticity and goal-directed learning in mice. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2023.08.30.555562. [PMID: 37693512 PMCID: PMC10491244 DOI: 10.1101/2023.08.30.555562] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/12/2023]
Abstract
The small G-protein Rac1 promotes the formation of filamentous actin (F-Actin). Actin is a major component of dendritic spines, and we previously found that alcohol alters actin composition and dendritic spine structure in the nucleus accumbens (NAc) and the dorsomedial striatum (DMS). To examine if Rac1 contributes to these alcohol-mediated adaptations, we measured the level of GTP-bound active Rac1 in the striatum of mice following 7 weeks of intermittent access to 20% alcohol. We found that chronic alcohol intake activates Rac1 in the DMS of male mice. In contrast, Rac1 is not activated by alcohol in the NAc and DLS of male mice, or in the DMS of female mice. Similarly, closely related small G-proteins are not activated by alcohol in the DMS, and Rac1 activity is not increased in the DMS by moderate alcohol or natural reward. To determine the consequences of alcohol-dependent Rac1 activation in the DMS of male mice, we inhibited endogenous Rac1 by infecting the DMS of mice with an AAV expressing a dominant negative form of the small G-protein (Rac1-DN). We found that overexpression of AAV-Rac1-DN in the DMS inhibits alcohol-mediated Rac1 signaling and attenuates alcohol-mediated F-actin polymerization, which corresponded with a decrease in dendritic arborization and spine maturation. Finally, we provide evidence to suggest that Rac1 in the DMS plays a role in alcohol-associated goal-directed learning. Together, our data suggest that Rac1 in the DMS plays an important role in alcohol-dependent structural plasticity and aberrant learning. Significance Statement Addiction, including alcohol use disorder, is characterized by molecular and cellular adaptations that promote maladaptive behaviors. We found that Rac1 was activated by alcohol in the dorsomedial striatum (DMS) of male mice. We show that alcohol-mediated Rac1 signaling is responsible for alterations in actin dynamics and neuronal morphology. We also present data to suggest that Rac1 is important for alcohol-associated learning processes. These results suggest that Rac1 in the DMS is an important contributor to adaptations that promote alcohol use disorder.
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9
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Teckentrup V, Kroemer NB. Mechanisms for survival: vagal control of goal-directed behavior. Trends Cogn Sci 2024; 28:237-251. [PMID: 38036309 DOI: 10.1016/j.tics.2023.11.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2023] [Revised: 11/01/2023] [Accepted: 11/02/2023] [Indexed: 12/02/2023]
Abstract
Survival is a fundamental physiological drive, and neural circuits have evolved to prioritize actions that meet the energy demands of the body. This fine-tuning of goal-directed actions based on metabolic states ('allostasis') is deeply rooted in our brain, and hindbrain nuclei orchestrate the vital communication between the brain and body through the vagus nerve. Despite mounting evidence for vagal control of allostatic behavior in animals, its broader function in humans is still contested. Based on stimulation studies, we propose that the vagal afferent pathway supports transitions between survival modes by gating the integration of ascending bodily signals, thereby regulating reward-seeking. By reconceptualizing vagal signals as catalysts for goal-directed behavior, our perspective opens new avenues for theory-driven translational work in mental disorders.
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Affiliation(s)
- Vanessa Teckentrup
- Department of Psychiatry and Psychotherapy, Tübingen Center for Mental Health, University of Tübingen, 72076 Tübingen, Germany; School of Psychology and Trinity College Institute of Neuroscience, Trinity College Dublin, Dublin 2, Ireland
| | - Nils B Kroemer
- Department of Psychiatry and Psychotherapy, Tübingen Center for Mental Health, University of Tübingen, 72076 Tübingen, Germany; Section of Medical Psychology, Department of Psychiatry and Psychotherapy, Faculty of Medicine, University of Bonn, 53127 Bonn, Germany; German Center for Mental Health (DZPG), 72076 Tübingen, Germany.
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10
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Rohner VL, Lamothe-Molina PJ, Patriarchi T. Engineering, applications, and future perspectives of GPCR-based genetically encoded fluorescent indicators for neuromodulators. J Neurochem 2024; 168:163-184. [PMID: 38288673 DOI: 10.1111/jnc.16045] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2023] [Revised: 12/20/2023] [Accepted: 12/22/2023] [Indexed: 02/23/2024]
Abstract
This review explores the evolving landscape of G-protein-coupled receptor (GPCR)-based genetically encoded fluorescent indicators (GEFIs), with a focus on their development, structural components, engineering strategies, and applications. We highlight the unique features of this indicator class, emphasizing the importance of both the sensing domain (GPCR structure and activation mechanism) and the reporting domain (circularly permuted fluorescent protein (cpFP) structure and fluorescence modulation). Further, we discuss indicator engineering approaches, including the selection of suitable cpFPs and expression systems. Additionally, we showcase the diversity and flexibility of their application by presenting a summary of studies where such indicators were used. Along with all the advantages, we also focus on the current limitations as well as common misconceptions that arise when using these indicators. Finally, we discuss future directions in indicator engineering, including strategies for screening with increased throughput, optimization of the ligand-binding properties, structural insights, and spectral diversity.
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Affiliation(s)
- Valentin Lu Rohner
- Institute of Pharmacology and Toxicology, University of Zürich, Zürich, Switzerland
| | | | - Tommaso Patriarchi
- Institute of Pharmacology and Toxicology, University of Zürich, Zürich, Switzerland
- Neuroscience Center Zurich, University and ETH Zurich, Zurich, Switzerland
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11
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Sayar-Atasoy N, Yavuz Y, Laule C, Dong C, Kim H, Rysted J, Flippo K, Davis D, Aklan I, Yilmaz B, Tian L, Atasoy D. Opioidergic signaling contributes to food-mediated suppression of AgRP neurons. Cell Rep 2024; 43:113630. [PMID: 38165803 PMCID: PMC10865729 DOI: 10.1016/j.celrep.2023.113630] [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: 10/11/2022] [Revised: 11/22/2023] [Accepted: 12/13/2023] [Indexed: 01/04/2024] Open
Abstract
Opioids are generally known to promote hedonic food consumption. Although much of the existing evidence is primarily based on studies of the mesolimbic pathway, endogenous opioids and their receptors are widely expressed in hypothalamic appetite circuits as well; however, their role in homeostatic feeding remains unclear. Using a fluorescent opioid sensor, deltaLight, here we report that mediobasal hypothalamic opioid levels increase by feeding, which directly and indirectly inhibits agouti-related protein (AgRP)-expressing neurons through the μ-opioid receptor (MOR). AgRP-specific MOR expression increases by energy surfeit and contributes to opioid-induced suppression of appetite. Conversely, its antagonists diminish suppression of AgRP neuron activity by food and satiety hormones. Mice with AgRP neuron-specific ablation of MOR expression have increased fat preference without increased motivation. These results suggest that post-ingestion release of endogenous opioids contributes to AgRP neuron inhibition to shape food choice through MOR signaling.
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Affiliation(s)
- Nilufer Sayar-Atasoy
- Department of Neuroscience and Pharmacology, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA
| | - Yavuz Yavuz
- Department of Neuroscience and Pharmacology, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA; Department of Physiology, School of Medicine, Yeditepe University, Istanbul 34755, Turkey
| | - Connor Laule
- Department of Neuroscience and Pharmacology, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA
| | - Chunyang Dong
- Department of Biochemistry and Molecular Medicine, School of Medicine, University of California, Davis, Davis, CA 95616, USA
| | - Hyojin Kim
- Department of Neuroscience and Pharmacology, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA
| | - Jacob Rysted
- Department of Neuroscience and Pharmacology, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA
| | - Kyle Flippo
- Department of Neuroscience and Pharmacology, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA
| | - Debbie Davis
- Department of Neuroscience and Pharmacology, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA
| | - Iltan Aklan
- Department of Neuroscience and Pharmacology, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA
| | - Bayram Yilmaz
- Department of Physiology, School of Medicine, Yeditepe University, Istanbul 34755, Turkey
| | - Lin Tian
- Department of Biochemistry and Molecular Medicine, School of Medicine, University of California, Davis, Davis, CA 95616, USA
| | - Deniz Atasoy
- Department of Neuroscience and Pharmacology, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA; Iowa Neuroscience Institute, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA; Fraternal Order of Eagles Diabetes Research Center (FOEDRC), Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA.
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12
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Nyema NT, McKnight AD, Vargas-Elvira AG, Schneps HM, Gold EG, Myers KP, Alhadeff AL. AgRP neuron activity promotes associations between sensory and nutritive signals to guide flavor preference. Mol Metab 2023; 78:101833. [PMID: 37925021 PMCID: PMC10665654 DOI: 10.1016/j.molmet.2023.101833] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/23/2023] [Revised: 10/20/2023] [Accepted: 10/30/2023] [Indexed: 11/06/2023] Open
Abstract
OBJECTIVE The learned associations between sensory cues (e.g., taste, smell) and nutritive value (e.g., calories, post-ingestive signaling) of foods powerfully influences our eating behavior [1], but the neural circuits that mediate these associations are not well understood. Here, we examined the role of agouti-related protein (AgRP)-expressing neurons - neurons which are critical drivers of feeding behavior [2; 3] - in mediating flavor-nutrient learning (FNL). METHODS Because mice prefer flavors associated with AgRP neuron activity suppression [4], we examined how optogenetic stimulation of AgRP neurons during intake influences FNL, and used fiber photometry to determine how endogenous AgRP neuron activity tracks associations between flavors and nutrients. RESULTS We unexpectedly found that tonic activity in AgRP neurons during FNL potentiated, rather than prevented, the development of flavor preferences. There were notable sex differences in the mechanisms for this potentiation. Specifically, in male mice, AgRP neuron activity increased flavor consumption during FNL training, thereby strengthening the association between flavors and nutrients. In female mice, AgRP neuron activity enhanced flavor-nutrient preferences independently of consumption during training, suggesting that AgRP neuron activity enhances the reward value of the nutrient-paired flavor. Finally, in vivo neural activity analyses demonstrated that acute AgRP neuron dynamics track the association between flavors and nutrients in both sexes. CONCLUSIONS Overall, these data (1) demonstrate that AgRP neuron activity enhances associations between flavors and nutrients in a sex-dependent manner and (2) reveal that AgRP neurons track and rapidly update these associations. Taken together, our findings provide new insight into the role of AgRP neurons in assimilating sensory and nutritive signals for food reinforcement.
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Affiliation(s)
- Nathaniel T Nyema
- Monell Chemical Senses Center, Philadelphia, PA 19104, USA; University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Aaron D McKnight
- Monell Chemical Senses Center, Philadelphia, PA 19104, USA; University of Pennsylvania, Philadelphia, PA 19104, USA
| | | | - Heather M Schneps
- Monell Chemical Senses Center, Philadelphia, PA 19104, USA; University of Pennsylvania, Philadelphia, PA 19104, USA
| | | | | | - Amber L Alhadeff
- Monell Chemical Senses Center, Philadelphia, PA 19104, USA; University of Pennsylvania, Philadelphia, PA 19104, USA.
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13
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So WL, Hu J, Jeffs L, Dempsey H, Lockie SH, Zigman JM, Stark R, Reichenbach A, Andrews ZB. Ghrelin signalling in AgRP neurons links metabolic state to the sensory regulation of AgRP neural activity. Mol Metab 2023; 78:101826. [PMID: 37898450 PMCID: PMC10643323 DOI: 10.1016/j.molmet.2023.101826] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/06/2023] [Revised: 10/11/2023] [Accepted: 10/13/2023] [Indexed: 10/30/2023] Open
Abstract
OBJECTIVE The sensory detection of food and food cues suppresses Agouti related peptide (AgRP) neuronal activity prior to consumption with greatest suppression occurring in response to highly caloric food or interoceptive energy need. However, the interoceptive mechanisms priming an appropriate AgRP neural response to external sensory information of food availability remain unexplored. Since hunger increases plasma ghrelin, we hypothesized that ghrelin receptor (GHSR) signalling on AgRP neurons is a key interoceptive mechanism integrating energy need with external sensory cues predicting caloric availability. METHODS We used in vivo photometry to measure the effects of ghrelin administration or fasting on AgRP neural activity with GCaMP6s and dopamine release in the nucleus accumbens with GRAB-DA in mice lacking ghrelin receptors in AgRP neurons. RESULTS The deletion of GHSR on AgRP neurons prevented ghrelin-induced food intake, motivation and AgRP activity. The presentation of food (peanut butter pellet) or a wooden dowel suppressed AgRP activity in fasted WT but not mice lacking GHSRs in AgRP neurons. Similarly, peanut butter and a wooden dowel increased dopamine release in the nucleus accumbens after ip ghrelin injection in WT but not mice lacking GHSRs in AgRP neurons. No difference in dopamine release was observed in fasted mice. Finally, ip ghrelin administration did not directly increase dopamine neural activity in the ventral tegmental area. CONCLUSIONS Our results suggest that AgRP GHSRs integrate an interoceptive state of energy need with external sensory information to produce an optimal change in AgRP neural activity. Thus, ghrelin signalling on AgRP neurons is more than just a feedback signal to increase AgRP activity during hunger.
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Affiliation(s)
- Wang Lok So
- Monash Biomedicine Discovery Institute and Department of Physiology, Monash University, Clayton 3800, Victoria, Australia
| | - Jiachen Hu
- Monash Biomedicine Discovery Institute and Department of Physiology, Monash University, Clayton 3800, Victoria, Australia
| | - Lotus Jeffs
- Monash Biomedicine Discovery Institute and Department of Physiology, Monash University, Clayton 3800, Victoria, Australia
| | - Harry Dempsey
- The Florey Institute of Neuroscience and Mental Health, Mental Health Division, Parkville, Melbourne, Australia
| | - Sarah H Lockie
- Monash Biomedicine Discovery Institute and Department of Physiology, Monash University, Clayton 3800, Victoria, Australia
| | - Jeffrey M Zigman
- Center for Hypothalamic Research, Department of Internal Medicine, UT Southwestern Medical Center, Dallas, TX, USA; Division of Endocrinology, Department of Internal Medicine, UT Southwestern Medical Center, Dallas, TX, USA; Department of Psychiatry, UT Southwestern Medical Center, Dallas, TX, USA
| | - Romana Stark
- Monash Biomedicine Discovery Institute and Department of Physiology, Monash University, Clayton 3800, Victoria, Australia
| | - Alex Reichenbach
- Monash Biomedicine Discovery Institute and Department of Physiology, Monash University, Clayton 3800, Victoria, Australia
| | - Zane B Andrews
- Monash Biomedicine Discovery Institute and Department of Physiology, Monash University, Clayton 3800, Victoria, Australia.
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14
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Lai TT, Liou CW, Tsai YH, Lin YY, Wu WL. Butterflies in the gut: the interplay between intestinal microbiota and stress. J Biomed Sci 2023; 30:92. [PMID: 38012609 PMCID: PMC10683179 DOI: 10.1186/s12929-023-00984-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2023] [Accepted: 11/06/2023] [Indexed: 11/29/2023] Open
Abstract
Psychological stress is a global issue that affects at least one-third of the population worldwide and increases the risk of numerous psychiatric disorders. Accumulating evidence suggests that the gut and its inhabiting microbes may regulate stress and stress-associated behavioral abnormalities. Hence, the objective of this review is to explore the causal relationships between the gut microbiota, stress, and behavior. Dysbiosis of the microbiome after stress exposure indicated microbial adaption to stressors. Strikingly, the hyperactivated stress signaling found in microbiota-deficient rodents can be normalized by microbiota-based treatments, suggesting that gut microbiota can actively modify the stress response. Microbiota can regulate stress response via intestinal glucocorticoids or autonomic nervous system. Several studies suggest that gut bacteria are involved in the direct modulation of steroid synthesis and metabolism. This review provides recent discoveries on the pathways by which gut microbes affect stress signaling and brain circuits and ultimately impact the host's complex behavior.
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Affiliation(s)
- Tzu-Ting Lai
- Department of Physiology, College of Medicine, National Cheng Kung University, 1 University Rd., Tainan, 70101, Taiwan
- Institute of Basic Medical Sciences, College of Medicine, National Cheng Kung University, 1 University Rd., Tainan, 70101, Taiwan
| | - Chia-Wei Liou
- Department of Physiology, College of Medicine, National Cheng Kung University, 1 University Rd., Tainan, 70101, Taiwan
- Institute of Basic Medical Sciences, College of Medicine, National Cheng Kung University, 1 University Rd., Tainan, 70101, Taiwan
| | - Yu-Hsuan Tsai
- Department of Physiology, College of Medicine, National Cheng Kung University, 1 University Rd., Tainan, 70101, Taiwan
- Institute of Basic Medical Sciences, College of Medicine, National Cheng Kung University, 1 University Rd., Tainan, 70101, Taiwan
| | - Yuan-Yuan Lin
- Department of Physiology, College of Medicine, National Cheng Kung University, 1 University Rd., Tainan, 70101, Taiwan
| | - Wei-Li Wu
- Department of Physiology, College of Medicine, National Cheng Kung University, 1 University Rd., Tainan, 70101, Taiwan.
- Institute of Basic Medical Sciences, College of Medicine, National Cheng Kung University, 1 University Rd., Tainan, 70101, Taiwan.
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15
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Klima ML, Kruger KA, Goldstein N, Pulido S, Low AYT, Assenmacher CA, Alhadeff AL, Betley JN. Anti-inflammatory effects of hunger are transmitted to the periphery via projection-specific AgRP circuits. Cell Rep 2023; 42:113338. [PMID: 37910501 DOI: 10.1016/j.celrep.2023.113338] [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: 02/14/2019] [Revised: 07/31/2023] [Accepted: 10/10/2023] [Indexed: 11/03/2023] Open
Abstract
Caloric restriction has anti-inflammatory effects. However, the coordinated physiological actions that lead to reduced inflammation in a state of caloric deficit (hunger) are largely unknown. Using a mouse model of injury-induced peripheral inflammation, we find that food deprivation reduces edema, temperature, and cytokine responses that occur after injury. The magnitude of the anti-inflammatory effect that occurs during hunger is more robust than that of non-steroidal anti-inflammatory drugs. The effects of hunger are recapitulated centrally by activity in nutrient-sensing hypothalamic agouti-related protein (AgRP)-expressing neurons. We find that AgRP neurons projecting to the paraventricular nucleus of the hypothalamus rapidly and robustly reduce inflammation and mediate the majority of hunger's anti-inflammatory effects. Intact vagal efferent signaling is required for the anti-inflammatory action of hunger, revealing a brain-to-periphery pathway for this reduction in inflammation. Taken together, these data begin to unravel a potent anti-inflammatory pathway engaged by hypothalamic AgRP neurons to reduce inflammation.
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Affiliation(s)
- Michelle L Klima
- Department of Biology, University of Pennsylvania, Philadelphia, PA 19104, USA; Department of Neuroscience, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Kayla A Kruger
- Department of Biology, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Nitsan Goldstein
- Department of Biology, University of Pennsylvania, Philadelphia, PA 19104, USA; Department of Neuroscience, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Santiago Pulido
- Department of Biology, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Aloysius Y T Low
- Department of Biology, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Charles-Antoine Assenmacher
- Comparative Pathology Core, Department of Pathobiology, University of Pennsylvania School of Veterinary Medicine, Philadelphia, PA 19104, USA
| | - Amber L Alhadeff
- Department of Neuroscience, University of Pennsylvania, Philadelphia, PA 19104, USA; Monell Chemical Senses Center, Philadelphia, PA 19104, USA.
| | - J Nicholas Betley
- Department of Biology, University of Pennsylvania, Philadelphia, PA 19104, USA; Department of Neuroscience, University of Pennsylvania, Philadelphia, PA 19104, USA.
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16
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Reed F, Reichenbach A, Dempsey H, Clarke RE, Mequinion M, Stark R, Rawlinson S, Foldi CJ, Lockie SH, Andrews ZB. Acute inhibition of hunger-sensing AgRP neurons promotes context-specific learning in mice. Mol Metab 2023; 77:101803. [PMID: 37690518 PMCID: PMC10523265 DOI: 10.1016/j.molmet.2023.101803] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/28/2023] [Revised: 08/29/2023] [Accepted: 09/06/2023] [Indexed: 09/12/2023] Open
Abstract
OBJECTIVE An environmental context, which reliably predicts food availability, can increase the appetitive food drive within the same environment context. However, hunger is required for the development of such a context-induced feeding (CIF) response, suggesting the neural circuits sensitive to hunger link an internal energy state with a particular environment context. Since Agouti related peptide (AgRP) neurons are activated by energy deficit, we hypothesised that AgRP neurons are both necessary and sufficient to drive CIF. METHODS To examine the role of AgRP neurons in the CIF process, we used fibre photometry with GCaMP7f, chemogenetic activation of AgRP neurons, as well as optogenetic control of AgRP neurons to facilitate acute temporal control not permitted with chemogenetics. RESULTS A CIF response at test was only observed when mice were fasted during context training and AgRP population activity at test showed an attenuated inhibitory response to food, suggesting increased food-seeking and/or decreased satiety signalling drives the increased feeding response at test. Intriguingly, chemogenetic activation of AgRP neurons during context training did not increase CIF, suggesting precise temporal firing properties may be required. Indeed, termination of AgRP neuronal photostimulation during context training (ON-OFF in context), in the presence or absence of food, increased CIF. Moreover, photoinhibition of AgRP neurons during context training in fasted mice was sufficient to drive a subsequent CIF in the absence of food. CONCLUSIONS Our results suggest that AgRP neurons regulate the acquisition of CIF when the acute inhibition of AgRP activity is temporally matched to context exposure. These results establish acute AgRP inhibition as a salient neural event underscoring the effect of hunger on associative learning.
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Affiliation(s)
- Felicia Reed
- Monash Biomedicine Discovery Institute and Department of Physiology, Monash University, Clayton, 3800, Victoria, Australia
| | - Alex Reichenbach
- Monash Biomedicine Discovery Institute and Department of Physiology, Monash University, Clayton, 3800, Victoria, Australia
| | - Harry Dempsey
- Monash Biomedicine Discovery Institute and Department of Physiology, Monash University, Clayton, 3800, Victoria, Australia
| | - Rachel E Clarke
- Department of Neurosciences, Medical University of South Carolina, Charleston, SC, 29425, USA
| | - Mathieu Mequinion
- Monash Biomedicine Discovery Institute and Department of Physiology, Monash University, Clayton, 3800, Victoria, Australia
| | - Romana Stark
- Monash Biomedicine Discovery Institute and Department of Physiology, Monash University, Clayton, 3800, Victoria, Australia
| | - Sasha Rawlinson
- Monash Biomedicine Discovery Institute and Department of Physiology, Monash University, Clayton, 3800, Victoria, Australia
| | - Claire J Foldi
- Monash Biomedicine Discovery Institute and Department of Physiology, Monash University, Clayton, 3800, Victoria, Australia
| | - Sarah H Lockie
- Monash Biomedicine Discovery Institute and Department of Physiology, Monash University, Clayton, 3800, Victoria, Australia
| | - Zane B Andrews
- Monash Biomedicine Discovery Institute and Department of Physiology, Monash University, Clayton, 3800, Victoria, Australia.
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17
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Stuber GD. Neurocircuits for motivation. Science 2023; 382:394-398. [PMID: 37883553 DOI: 10.1126/science.adh8287] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2023] [Accepted: 09/22/2023] [Indexed: 10/28/2023]
Abstract
The nervous system coordinates various motivated behaviors such as feeding, drinking, and escape to promote survival and evolutionary fitness. Although the precise behavioral repertoires required for distinct motivated behaviors are diverse, common features such as approach or avoidance suggest that common brain substrates are required for a wide range of motivated behaviors. In this Review, I describe a framework by which neural circuits specified for some innate drives regulate the activity of ventral tegmental area (VTA) dopamine neurons to reinforce ongoing or planned actions to fulfill motivational demands. This framework may explain why signaling from VTA dopamine neurons is ubiquitously involved in many types of diverse volitional motivated actions, as well as how sensory and interoceptive cues can initiate specific goal-directed actions.
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Affiliation(s)
- Garret D Stuber
- Center for the Neurobiology of Addiction, Pain, and Emotion, University of Washington, Seattle, WA 98195, USA
- Department of Anesthesiology and Pain Medicine, University of Washington, Seattle, WA 98195, USA
- Department of Pharmacology, University of Washington, Seattle, WA 98195, USA
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18
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Speakman JR, Hall KD. Models of body weight and fatness regulation. Philos Trans R Soc Lond B Biol Sci 2023; 378:20220231. [PMID: 37661735 PMCID: PMC10475878 DOI: 10.1098/rstb.2022.0231] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2023] [Accepted: 07/13/2023] [Indexed: 09/05/2023] Open
Abstract
Body weight and fatness appear to be regulated phenomena. Several different theoretical models are available to capture the essence of this idea. These include the set-point, dynamic equilibrium, adiposity force, control theory-settling point, Hall-Guo, operation point and dual intervention point (DIP) models. The set-point model posits a single reference point around which levels of fat are regulated. The dynamic equilibrium model suggests that the apparent regulation of body fat around a reference point is an illusion owing to the necessary impacts of weight change on energy expenditure. Control theory focuses on the importance of feedback gain and suggests set-point and dynamic equilibrium are ends of a continuum of feedback gain. Control theory models have also been called 'settling point' models. The Hall-Guo, operation point and DIP models also bring together the set-point and dynamic equilibrium ideas into a single framework. The DIP proposes a zone of indifference where dynamic equilibrium 'regulation' predominates, bounded by upper and lower intervention points beyond which physiological mechanisms are activated. The drifty gene hypothesis is an idea explaining where this individual variation in the upper intervention point might come from. We conclude that further experiments to test between the models are sorely required. This article is part of a discussion meeting issue 'Causes of obesity: theories, conjectures and evidence (Part II)'.
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Affiliation(s)
- John R. Speakman
- Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen, Guangdong Province, 518055, People's Republic of China
- School of Biological and Environmental Sciences, University of Aberdeen, Aberdeen, AB24 2TZ, UK
- Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, 100101, People's Republic of China
- China Medical University, Shenyang, Liaoning Province, 110122, People's Republic of China
| | - Kevin D. Hall
- National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, USA
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19
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Vento PJ, Watson JR, Pullmann D, Black SL, Tomberlin JS, Jhou TC. Pumping the brakes: rostromedial tegmental inhibition of compulsive cocaine seeking. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.10.04.560908. [PMID: 38405989 PMCID: PMC10889025 DOI: 10.1101/2023.10.04.560908] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 02/27/2024]
Abstract
Addiction is marked by aberrant decision-making and an inability to suppress inappropriate and often dangerous behaviors. We previously demonstrated that inactivation of the rostromedial tegmental nucleus (RMTg) in rats causes persistent food seeking despite impending aversive footshock, an effect strikingly similar to the punishment resistance observed in people with a history of protracted drug use [1]. Here, we extend these studies to demonstrate chemogenetic silencing of RMTg axonal projections to the ventral tegmental area (VTA) (RMTg→VTA pathway) causes rats to endure significantly more footshock to receive cocaine infusions. To further test whether activation of this circuit is sufficient to suppress reward seeking in the absence of an overtly aversive stimulus, we used temporally specific optogenetic stimulation of the RMTg→VTA pathway as a "punisher" in place of footshock following lever pressing for either food or cocaine reward. While optical stimulation of the RMTg→VTA pathway robustly suppressed lever pressing for food, we found that stimulation of this circuit had only modest effects on suppressing responding for cocaine infusions. Even though optical RMTg→VTA stimulation was not particularly effective at reducing ongoing cocaine use, this experience nevertheless had long-lasting consequences, as reinstatement of drug seeking in response to cocaine-associated cues was profoundly suppressed when tested nearly two weeks later. These results suggest the RMTg may serve as a useful target for producing enduring reductions in drug craving, particularly during periods of abstinence from drug use.
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Affiliation(s)
- Peter J Vento
- Department of Psychology, University of South Carolina, Columbia, SC
| | - Jacob R Watson
- Department of Psychology, University of South Carolina, Columbia, SC
| | - Dominika Pullmann
- Department of Neuroscience, Medical University of South Carolina, Charleston, SC
| | | | - Jensen S Tomberlin
- Department of Neuroscience, Medical University of South Carolina, Charleston, SC
| | - Thomas C Jhou
- Department of Neuroscience, Medical University of South Carolina, Charleston, SC
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20
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Darcey VL, Guo J, Chi M, Chung ST, Courville AB, Gallagher I, Herscovitch P, Howard R, LaNoire M, Milley L, Schick A, Stagliano M, Turner S, Urbanski N, Yang S, Yim E, Zhai N, Zhou MS, Hall KD. Striatal dopamine tone is positively associated with body mass index in humans as determined by PET using dual dopamine type-2 receptor antagonist tracers. MEDRXIV : THE PREPRINT SERVER FOR HEALTH SCIENCES 2023:2023.09.27.23296169. [PMID: 37886556 PMCID: PMC10602123 DOI: 10.1101/2023.09.27.23296169] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/28/2023]
Abstract
The relationship between adiposity and dopamine type-2 receptor binding potential (D2BP) in the human brain has been repeatedly studied for >20 years with highly discrepant results, likely due to variable methodologies and differing study populations. We conducted a controlled inpatient feeding study to measure D2BP in the striatum using positron emission tomography with both [18F]fallypride and [11C]raclopride in pseudo-random order in 54 young adults with a wide range of body mass index (BMI 20-44 kg/m2). Within-subject D2BP measurements using the two tracers were moderately correlated (r=0.47, p<0.001). D2BP was negatively correlated with BMI as measured by [11C]raclopride (r= -0.51; p<0.0001) but not [18F]fallypride (r=-0.01; p=0.92) and these correlation coefficients were significantly different from each other (p<0.001). Given that [18F]fallypride has greater binding affinity to dopamine type-2 receptors than [11C]raclopride, which is more easily displaced by endogenous dopamine, our results suggest that adiposity is positively associated with increased striatal dopamine tone.
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Affiliation(s)
- Valerie L Darcey
- Integrative Physiology Section, National Institute of Diabetes & Digestive & Kidney Diseases, National Institutes of Health, Bethesda, MD, USA
- Center on Compulsive Behaviors, Intramural Research Program, NIH, Bethesda, MD, USA
| | - Juen Guo
- Integrative Physiology Section, National Institute of Diabetes & Digestive & Kidney Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Meible Chi
- Integrative Physiology Section, National Institute of Diabetes & Digestive & Kidney Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Stephanie T Chung
- Diabetes, Endocrinology, and Obesity Branch, National Institute of Diabetes, Digestive, and Kidney Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Amber B Courville
- Human Energy and Body Weight Regulation Core, National Institute of Diabetes & Digestive & Kidney Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Isabelle Gallagher
- Integrative Physiology Section, National Institute of Diabetes & Digestive & Kidney Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Peter Herscovitch
- Positron Emission Tomography Department, Clinical Center, National Institutes of Health, Bethesda, MD, USA
| | - Rebecca Howard
- Integrative Physiology Section, National Institute of Diabetes & Digestive & Kidney Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Melissa LaNoire
- Integrative Physiology Section, National Institute of Diabetes & Digestive & Kidney Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Lauren Milley
- Integrative Physiology Section, National Institute of Diabetes & Digestive & Kidney Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Alex Schick
- Integrative Physiology Section, National Institute of Diabetes & Digestive & Kidney Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Michael Stagliano
- Integrative Physiology Section, National Institute of Diabetes & Digestive & Kidney Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Sara Turner
- Nutrition Department, Clinical Center, National Institutes of Health, Bethesda, MD, USA
| | - Nicholas Urbanski
- Integrative Physiology Section, National Institute of Diabetes & Digestive & Kidney Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Shanna Yang
- Nutrition Department, Clinical Center, National Institutes of Health, Bethesda, MD, USA
| | - Eunha Yim
- University of Maryland, College Park, MD, USA
| | - Nan Zhai
- Integrative Physiology Section, National Institute of Diabetes & Digestive & Kidney Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Megan S Zhou
- Integrative Physiology Section, National Institute of Diabetes & Digestive & Kidney Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Kevin D Hall
- Integrative Physiology Section, National Institute of Diabetes & Digestive & Kidney Diseases, National Institutes of Health, Bethesda, MD, USA
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21
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Bijoch Ł, Klos J, Pękała M, Fiołna K, Kaczmarek L, Beroun A. Diverse processing of pharmacological and natural rewards by the central amygdala. Cell Rep 2023; 42:113036. [PMID: 37616162 DOI: 10.1016/j.celrep.2023.113036] [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: 02/17/2023] [Revised: 07/03/2023] [Accepted: 08/11/2023] [Indexed: 08/25/2023] Open
Abstract
The central amygdala (CeA) with its medial (CeM) and lateral (CeL) nuclei is the brain hub for processing stimuli with emotional context. CeL nucleus gives a strong inhibitory input to the CeM, and this local circuitry assigns values (positive or negative) to incoming stimuli, guiding appropriate behavior (approach or avoid). However, the particular involvement of CeA in processing such emotionally relevant information and adaptations of the CeA circuitry are not yet well understood. In this study, we examined synaptic plasticity in the CeA after exposure to two types of rewards, pharmacological (cocaine) and natural (sugar). We found that both rewards engage CeM, where they generate silent synapses resulting in the strengthening of the network. However, only cocaine triggers plasticity in the CeL, which leads to the weakening of its excitatory inputs. Finally, chemogenetic inhibition of CeM attenuates animal preference for sugar, while activation delays cocaine-induced increase in locomotor activity.
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Affiliation(s)
- Łukasz Bijoch
- Nencki-EMBL Center of Excellence for Neural Plasticity and Brain Disorders: BRAINCITY, Laboratory of Neuronal Plasticity, Nencki Institute of Experimental Biology of the Polish Academy of Sciences, L. Pasteura 3, 02-093 Warsaw, Poland
| | - Joanna Klos
- Nencki-EMBL Center of Excellence for Neural Plasticity and Brain Disorders: BRAINCITY, Laboratory of Neuronal Plasticity, Nencki Institute of Experimental Biology of the Polish Academy of Sciences, L. Pasteura 3, 02-093 Warsaw, Poland
| | - Martyna Pękała
- Nencki-EMBL Center of Excellence for Neural Plasticity and Brain Disorders: BRAINCITY, Laboratory of Neurobiology, Nencki Institute of Experimental Biology of the Polish Academy of Sciences, L. Pasteura 3, 02-093 Warsaw, Poland
| | - Kristina Fiołna
- Nencki-EMBL Center of Excellence for Neural Plasticity and Brain Disorders: BRAINCITY, Laboratory of Neuronal Plasticity, Nencki Institute of Experimental Biology of the Polish Academy of Sciences, L. Pasteura 3, 02-093 Warsaw, Poland; Nencki-EMBL Center of Excellence for Neural Plasticity and Brain Disorders: BRAINCITY, Laboratory of Neurobiology, Nencki Institute of Experimental Biology of the Polish Academy of Sciences, L. Pasteura 3, 02-093 Warsaw, Poland
| | - Leszek Kaczmarek
- Nencki-EMBL Center of Excellence for Neural Plasticity and Brain Disorders: BRAINCITY, Laboratory of Neurobiology, Nencki Institute of Experimental Biology of the Polish Academy of Sciences, L. Pasteura 3, 02-093 Warsaw, Poland
| | - Anna Beroun
- Nencki-EMBL Center of Excellence for Neural Plasticity and Brain Disorders: BRAINCITY, Laboratory of Neuronal Plasticity, Nencki Institute of Experimental Biology of the Polish Academy of Sciences, L. Pasteura 3, 02-093 Warsaw, Poland.
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22
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Nyema NT, McKnight AD, Vargas-Elvira AG, Schneps HM, Gold EG, Myers KP, Alhadeff AL. AgRP neuron activity promotes associations between sensory and nutritive signals to guide flavor preference. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.09.19.558483. [PMID: 37786670 PMCID: PMC10541598 DOI: 10.1101/2023.09.19.558483] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/04/2023]
Abstract
Objective The learned associations between sensory cues (e.g., taste, smell) and nutritive value (e.g., calories, post-ingestive signaling) of foods powerfully influences our eating behavior [1], but the neural circuits that mediate these associations are not well understood. Here, we examined the role of agouti-related protein (AgRP)-expressing neurons - neurons which are critical drivers of feeding behavior [2; 3] - in mediating flavor-nutrient learning (FNL). Methods Because mice prefer flavors associated with AgRP neuron activity suppression [4], we examined how optogenetic stimulation of AgRP neurons during intake influences FNL, and used fiber photometry to determine how endogenous AgRP neuron activity tracks associations between flavors and nutrients. Results We unexpectedly found that tonic activity in AgRP neurons during FNL potentiated, rather than prevented, the development of flavor preferences. There were notable sex differences in the mechanisms for this potentiation. Specifically, in male mice, AgRP neuron activity increased flavor consumption during FNL training, thereby strengthening the association between flavors and nutrients. In female mice, AgRP neuron activity enhanced flavor-nutrient preferences independently of consumption during training, suggesting that AgRP neuron activity enhances the reward value of the nutrient-paired flavor. Finally, in vivo neural activity analyses demonstrated that acute AgRP neuron dynamics track the association between flavors and nutrients in both sexes. Conclusions Overall, these data (1) demonstrate that AgRP neuron activity enhances associations between flavors and nutrients in a sex-dependent manner and (2) reveal that AgRP neurons track and update these associations on fast timescales. Taken together, our findings provide new insight into the role of AgRP neurons in assimilating sensory and nutritive signals for food reinforcement.
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Affiliation(s)
- Nathaniel T. Nyema
- Monell Chemical Senses Center, Philadelphia PA 19104, USA
- University of Pennsylvania, Philadelphia PA 19104, USA
| | - Aaron D. McKnight
- Monell Chemical Senses Center, Philadelphia PA 19104, USA
- University of Pennsylvania, Philadelphia PA 19104, USA
| | | | - Heather M. Schneps
- Monell Chemical Senses Center, Philadelphia PA 19104, USA
- University of Pennsylvania, Philadelphia PA 19104, USA
| | | | | | - Amber L. Alhadeff
- Monell Chemical Senses Center, Philadelphia PA 19104, USA
- University of Pennsylvania, Philadelphia PA 19104, USA
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23
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Zhang SX, Kim A, Madara JC, Zhu PK, Christenson LF, Lutas A, Kalugin PN, Jin Y, Pal A, Tian L, Lowell BB, Andermann ML. Competition between stochastic neuropeptide signals calibrates the rate of satiation. RESEARCH SQUARE 2023:rs.3.rs-3185572. [PMID: 37546985 PMCID: PMC10402269 DOI: 10.21203/rs.3.rs-3185572/v1] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/08/2023]
Abstract
We investigated how transmission of hunger- and satiety-promoting neuropeptides, NPY and αMSH, is integrated at the level of intracellular signaling to control feeding. Receptors for these peptides use the second messenger cAMP. How cAMP integrates opposing peptide signals to regulate energy balance, and the in vivo spatiotemporal dynamics of endogenous peptidergic signaling, remain largely unknown. We show that AgRP axon stimulation in the paraventricular hypothalamus evokes probabilistic NPY release that triggers stochastic cAMP decrements in downstream MC4R-expressing neurons (PVHMC4R). Meanwhile, POMC axon stimulation triggers stochastic, αMSH-dependent cAMP increments. Release of either peptide impacts a ~100 μm diameter region, and when these peptide signals overlap, they compete to control cAMP. The competition is reflected by hunger-state-dependent differences in the amplitude and persistence of cAMP transients: hunger peptides are more efficacious in the fasted state, satiety peptides in the fed state. Feeding resolves the competition by simultaneously elevating αMSH release and suppressing NPY release, thereby sustaining elevated cAMP in PVHMC4R neurons. In turn, cAMP potentiates feeding-related excitatory inputs and promotes satiation across minutes. Our findings highlight how biochemical integration of opposing, quantal peptide signals during energy intake orchestrates a gradual transition between stable states of hunger and satiety.
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Affiliation(s)
- Stephen X Zhang
- Division of Endocrinology, Diabetes and Metabolism, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215, USA
- Co-corresponding authors
| | - Angela Kim
- Division of Endocrinology, Diabetes and Metabolism, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215, USA
| | - Joseph C Madara
- Division of Endocrinology, Diabetes and Metabolism, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215, USA
| | - Paula K Zhu
- Division of Endocrinology, Diabetes and Metabolism, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215, USA
| | - Lauren F Christenson
- Division of Endocrinology, Diabetes and Metabolism, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215, USA
| | - Andrew Lutas
- Division of Endocrinology, Diabetes and Metabolism, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215, USA
- Present address: Diabetes, Endocrinology, and Obesity Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Peter N Kalugin
- Division of Endocrinology, Diabetes and Metabolism, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215, USA
- Program in Neuroscience, Harvard University, Cambridge, MA 02138, USA
| | - Yihan Jin
- Department of Biochemistry and Molecular Medicine, School of Medicine, University of California, Davis, Sacramento, CA 95817, USA
| | - Akash Pal
- Department of Biochemistry and Molecular Medicine, School of Medicine, University of California, Davis, Sacramento, CA 95817, USA
| | - Lin Tian
- Department of Biochemistry and Molecular Medicine, School of Medicine, University of California, Davis, Sacramento, CA 95817, USA
| | - Bradford B Lowell
- Division of Endocrinology, Diabetes and Metabolism, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215, USA
| | - Mark L Andermann
- Division of Endocrinology, Diabetes and Metabolism, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215, USA
- Program in Neuroscience, Harvard University, Cambridge, MA 02138, USA
- Department of Neurobiology, Harvard Medical School, Boston, MA 02115, USA
- Co-corresponding authors
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24
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Zhang SX, Kim A, Madara JC, Zhu PK, Christenson LF, Lutas A, Kalugin PN, Jin Y, Pal A, Tian L, Lowell BB, Andermann ML. Competition between stochastic neuropeptide signals calibrates the rate of satiation. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.07.11.548551. [PMID: 37503012 PMCID: PMC10369917 DOI: 10.1101/2023.07.11.548551] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/29/2023]
Abstract
We investigated how transmission of hunger- and satiety-promoting neuropeptides, NPY and αMSH, is integrated at the level of intracellular signaling to control feeding. Receptors for these peptides use the second messenger cAMP, but the messenger's spatiotemporal dynamics and role in energy balance are controversial. We show that AgRP axon stimulation in the paraventricular hypothalamus evokes probabilistic and spatially restricted NPY release that triggers stochastic cAMP decrements in downstream MC4R-expressing neurons (PVH MC4R ). Meanwhile, POMC axon stimulation triggers stochastic, αMSH-dependent cAMP increments. NPY and αMSH competitively control cAMP, as reflected by hunger-state-dependent differences in the amplitude and persistence of cAMP transients evoked by each peptide. During feeding bouts, elevated αMSH release and suppressed NPY release cooperatively sustain elevated cAMP in PVH MC4R neurons, thereby potentiating feeding-related excitatory inputs and promoting satiation across minutes. Our findings highlight how state-dependent integration of opposing, quantal peptidergic events by a common biochemical target calibrates energy intake.
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25
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Zheng Y, Li Y. Past, present, and future of tools for dopamine detection. Neuroscience 2023:S0306-4522(23)00295-6. [PMID: 37419404 DOI: 10.1016/j.neuroscience.2023.06.025] [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: 05/18/2023] [Revised: 06/26/2023] [Accepted: 06/29/2023] [Indexed: 07/09/2023]
Abstract
Dopamine (DA) is a critical neuromodulator involved in various brain functions. To understand how DA regulates neural circuits and behaviors in the physiological and pathological conditions, it is essential to have tools that enable the direct detection of DA dynamics in vivo. Recently, genetically encoded DA sensors based on G protein-coupled receptors revolutionized this field, as it allows us to track in vivo DA dynamic with unprecedented spatial-temporal resolution, high molecular specificity, and sub-second kinetics. In this review, we first summarize traditional DA detection methods. Then we focus on the development of genetically encoded DA sensors and feature its significance to understanding dopaminergic neuromodulation across diverse behaviors and species. Finally, we present our perspectives about the future direction of the next-generation DA sensors and extend their potential applications. Overall, this review offers a comprehensive perspective on the past, present, and future of DA detection tools, with important implications for the study of DA functions in health and disease.
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Affiliation(s)
- Yu Zheng
- Peking-Tsinghua Center for Life Sciences, 100871 Beijing, China
| | - Yulong Li
- Peking-Tsinghua Center for Life Sciences, 100871 Beijing, China; State Key Laboratory of Membrane Biology, Peking University School of Life Sciences, 100871 Beijing, China; PKU-IDG/McGovern Institute for Brain Research, 100871 Beijing, China; National Biomedical Imaging Center, Peking University, 100871 Beijing, China.
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26
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Darcey VL, Guo J, Courville AB, Gallagher I, Avery JA, Simmons WK, Ingeholm JE, Herscovitch P, Martin A, Hall KD. Dietary fat restriction affects brain reward regions in a randomized crossover trial. JCI Insight 2023; 8:e169759. [PMID: 37345661 PMCID: PMC10371234 DOI: 10.1172/jci.insight.169759] [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: 02/14/2023] [Accepted: 05/10/2023] [Indexed: 06/23/2023] Open
Abstract
BACKGROUNDWeight-loss diets often target dietary fat or carbohydrates, macronutrients that are sensed via distinct gut-brain pathways and differentially affect peripheral hormones and metabolism. However, the effects of such diet changes on the human brain are unclear. METHODSWe investigated whether selective isocaloric reductions in dietary fat or carbohydrates altered dopamine D2/3 receptor binding potential (D2BP) and neural activity in brain-reward regions in response to visual food cues in 17 inpatient adults with obesity as compared with a eucaloric baseline diet using a randomized crossover design. RESULTSOn the fifth day of dietary fat restriction, but not carbohydrate restriction, both D2BP and neural activity to food cues were decreased in brain-reward regions. After the reduced-fat diet, ad libitum intake shifted toward foods high in both fat and carbohydrates. CONCLUSIONThese results suggest that dietary fat restriction increases tonic dopamine in brain-reward regions and affects food choice in ways that may hamper diet adherence. TRIAL REGISTRATIONClinicalTrials.gov NCT00846040 FUNDING. NIDDK 1ZIADK013037.
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Affiliation(s)
- Valerie L Darcey
- Integrative Physiology Section, National Institute of Diabetes & Digestive & Kidney Diseases, Bethesda, Maryland, USA
| | - Juen Guo
- Integrative Physiology Section, National Institute of Diabetes & Digestive & Kidney Diseases, Bethesda, Maryland, USA
| | - Amber B Courville
- Human Energy and Body Weight Regulation Core, National Institute of Diabetes & Digestive & Kidney Diseases, Bethesda, Maryland, USA
| | - Isabelle Gallagher
- Integrative Physiology Section, National Institute of Diabetes & Digestive & Kidney Diseases, Bethesda, Maryland, USA
| | - Jason A Avery
- Laboratory of Brain and Cognition, National Institute of Mental Health, Rockland, Maryland, USA
| | - W Kyle Simmons
- Biomedical Imaging Center, Oklahoma State University, Stillwater, Oklahoma, USA
| | - John E Ingeholm
- Laboratory of Brain and Cognition, National Institute of Mental Health, Rockland, Maryland, USA
| | - Peter Herscovitch
- Clinical Center Positron Emission Tomography Department, NIH, Bethesda, Maryland, USA
| | - Alex Martin
- Laboratory of Brain and Cognition, National Institute of Mental Health, Rockland, Maryland, USA
| | - Kevin D Hall
- Integrative Physiology Section, National Institute of Diabetes & Digestive & Kidney Diseases, Bethesda, Maryland, USA
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27
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Bansal P, Roitman MF, Jung EE. Caloric state modulates locomotion, heart rate and motor neuron responses to acute administration of d-amphetamine in zebrafish larvae. Physiol Behav 2023; 264:114144. [PMID: 36889488 PMCID: PMC10070120 DOI: 10.1016/j.physbeh.2023.114144] [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: 10/19/2022] [Revised: 02/28/2023] [Accepted: 03/02/2023] [Indexed: 03/08/2023]
Abstract
Psychostimulant drugs increase behavioral, cardiac and brain responses in humans and other animals. Acute food deprivation or chronic food restriction potentiates the stimulatory effects of abused drugs and increases the propensity for relapse to drug seeking in drug-experienced animals. The mechanisms by which hunger affects cardiac and behavioral activities are only beginning to be elucidated. Moreover, changes in motor neuron activities at the single neuron level induced by psychostimulants, and their modulation by food restriction, remain unknown. Here we investigated how food deprivation affects responses to d-amphetamine by measuring locomotor activity, cardiac output, and individual motor neuron activity in zebrafish larvae. We used wild-type larval zebrafish to record behavioral and cardiac responses and the larvae of Tg(mnx1:GCaMP5) transgenic zebrafish to record motor neuron responses. Physiological state gated responses to d-amphetamine. That is, d-amphetamine evoked significant increases in motor behavior (swimming distances), heart rate and motor neuron firing frequency in food-deprived but not fed zebrafish larvae. The results extend the finding that signals arising from food deprivation are a key potentiator of the drug responses induced by d-amphetamine to the zebrafish model. The larval zebrafish is an ideal model to further elucidate this interaction and identify key neuronal substrates that may increase vulnerability to drug reinforcement, drug-seeking and relapse.
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Affiliation(s)
- Pushkar Bansal
- Department of Mechanical and Industrial Engineering, The University of Illinois at Chicago, 842 W. Taylor St., Chicago, IL 60607, USA
| | - Mitchell F Roitman
- Department of Psychology, The University of Illinois at Chicago, 1007 W. Harrison St., Chicago, IL 60607, USA
| | - Erica E Jung
- Department of Mechanical and Industrial Engineering, The University of Illinois at Chicago, 842 W. Taylor St., Chicago, IL 60607, USA; Department of Biomedical Engineering, The University of Illinois at Chicago, 851 S. Morgan St., Chicago, IL 60607, USA.
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28
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Gearhardt AN, DiFeliceantonio AG. Highly processed foods can be considered addictive substances based on established scientific criteria. Addiction 2023; 118:589-598. [PMID: 36349900 DOI: 10.1111/add.16065] [Citation(s) in RCA: 17] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/09/2022] [Accepted: 09/15/2022] [Indexed: 11/10/2022]
Abstract
BACKGROUND There is growing evidence that an addictive-eating phenotype may exist. There is significant debate regarding whether highly processed foods (HPFs; foods with refined carbohydrates and/or added fats) are addictive. The lack of scientifically grounded criteria to evaluate the addictive nature of HPFs has hindered the resolution of this debate. ANALYSIS The most recent scientific debate regarding a substance's addictive potential centered around tobacco. In 1988, the Surgeon General issued a report identifying tobacco products as addictive based on three primary scientific criteria: their ability to (1) cause highly controlled or compulsive use, (2) cause psychoactive (i.e. mood-altering) effects via their effect on the brain and (3) reinforce behavior. Scientific advances have now identified the ability of tobacco products to (4) trigger strong urges or craving as another important indicator of addictive potential. Here, we propose that these four criteria provide scientifically valid benchmarks that can be used to evaluate the addictiveness of HPFs. Then, we review the evidence regarding whether HPFs meet each criterion. Finally, we consider the implications of labeling HPFs as addictive. CONCLUSION Highly processed foods (HPFs) can meet the criteria to be labeled as addictive substances using the standards set for tobacco products. The addictive potential of HPFs may be a key factor contributing to the high public health costs associated with a food environment dominated by cheap, accessible and heavily marketed HPFs.
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Affiliation(s)
| | - Alexandra G DiFeliceantonio
- Fralin Biomedical Research Institute at VTC, Roanoke, VA, USA.,Department of Human Nutrition Foods, and Exercise, Virginia Polytechnic Institute and State University, Blacksburg, VA, USA
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29
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Korgan AC, Oliveira-Abreu K, Wei W, Martin SLA, Bridges ZJD, Leal-Cardoso JH, Kaczorowski CC, O'Connell KMS. High sucrose consumption decouples intrinsic and synaptic excitability of AgRP neurons without altering body weight. Int J Obes (Lond) 2023; 47:224-235. [PMID: 36725979 PMCID: PMC10023568 DOI: 10.1038/s41366-023-01265-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/04/2022] [Revised: 01/17/2023] [Accepted: 01/19/2023] [Indexed: 02/03/2023]
Abstract
BACKGROUND/OBJECTIVE As the obesity epidemic continues, the understanding of macronutrient influence on central nervous system function is critical for understanding diet-induced obesity and potential therapeutics, particularly in light of the increased sugar content in processed foods. Previous research showed mixed effects of sucrose feeding on body weight gain but has yet to reveal insight into the impact of sucrose on hypothalamic functioning. Here, we explore the impact of liquid sucrose feeding for 12 weeks on body weight, body composition, caloric intake, and hypothalamic AgRP neuronal function and synaptic plasticity. METHODS Patch-clamp electrophysiology of hypothalamic AgRP neurons, metabolic phenotyping and food intake were performed on C57BL/6J mice. RESULTS While mice given sugar-sweetened water do not gain significant weight, they do show subtle differences in body composition and caloric intake. When given sugar-sweetened water, mice show similar alterations to AgRP neuronal excitability as in high-fat diet obese models. Increased sugar consumption also primes mice for increased caloric intake and weight gain when given access to a HFD. CONCLUSIONS Our results show that elevated sucrose consumption increased activity of AgRP neurons and altered synaptic excitability. This may contribute to obesity in mice and humans with access to more palatable (HFD) diets.
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Affiliation(s)
- Austin C Korgan
- The Jackson Laboratory for Mammalian Genetics, Bar Harbor, ME, USA
| | - Klausen Oliveira-Abreu
- The Jackson Laboratory for Mammalian Genetics, Bar Harbor, ME, USA
- Instituto Superior de Ciências Biomédicas, Universidade Estadual do Ceará, Fortaleza, CE, Brazil
| | - Wei Wei
- The Jackson Laboratory for Mammalian Genetics, Bar Harbor, ME, USA
- Georgia State University, Atlanta, GA, USA
| | | | - Zoey J D Bridges
- The Jackson Laboratory for Mammalian Genetics, Bar Harbor, ME, USA
| | | | - Catherine C Kaczorowski
- The Jackson Laboratory for Mammalian Genetics, Bar Harbor, ME, USA
- Graduate School of Biomedical Science and Engineering, University of Maine, Orono, ME, USA
- Neuroscience Program, Graduate School of Biomedical Science, Tufts University School of Medicine, Boston, MA, USA
| | - Kristen M S O'Connell
- The Jackson Laboratory for Mammalian Genetics, Bar Harbor, ME, USA.
- Graduate School of Biomedical Science and Engineering, University of Maine, Orono, ME, USA.
- Neuroscience Program, Graduate School of Biomedical Science, Tufts University School of Medicine, Boston, MA, USA.
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30
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Kroning KE, Wang W. Genetically encoded tools for in vivo G-protein-coupled receptor agonist detection at cellular resolution. Clin Transl Med 2022; 12:e1124. [PMID: 36446954 PMCID: PMC9708909 DOI: 10.1002/ctm2.1124] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2022] [Revised: 10/10/2022] [Accepted: 11/11/2022] [Indexed: 12/03/2022] Open
Abstract
G-protein-coupled receptors (GPCRs) are the most abundant receptor type in the human body and are responsible for regulating many physiological processes, such as sensation, cognition, muscle contraction and metabolism. Further, GPCRs are widely expressed in the brain where their agonists make up a large number of neurotransmitters and neuromodulators. Due to the importance of GPCRs in human physiology, genetically encoded sensors have been engineered to detect GPCR agonists at cellular resolution in vivo. These sensors can be placed into two main categories: those that offer real-time information on the signalling dynamics of GPCR agonists and those that integrate the GPCR agonist signal into a permanent, quantifiable mark that can be used to detect GPCR agonist localisation in a large brain area. In this review, we discuss the various designs of real-time and integration sensors, their advantages and limitations, and some in vivo applications. We also discuss the potential of using real-time and integrator sensors together to identify neuronal circuits affected by endogenous GPCR agonists and perform detailed characterisations of the spatiotemporal dynamics of GPCR agonist release in those circuits. By using these sensors together, the overall knowledge of GPCR-mediated signalling can be expanded.
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Affiliation(s)
- Kayla E. Kroning
- Life Sciences Institute, University of MichiganAnn ArborMichiganUSA
- Department of ChemistryUniversity of MichiganAnn ArborMichiganUSA
| | - Wenjing Wang
- Life Sciences Institute, University of MichiganAnn ArborMichiganUSA
- Department of ChemistryUniversity of MichiganAnn ArborMichiganUSA
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31
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Zhang Q, Tang Q, Purohit NM, Davenport JB, Brennan C, Patel RK, Godschall E, Zwiefel LS, Spano A, Campbell JN, Güler AD. Food-induced dopamine signaling in AgRP neurons promotes feeding. Cell Rep 2022; 41:111718. [PMID: 36450244 PMCID: PMC9753708 DOI: 10.1016/j.celrep.2022.111718] [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: 02/23/2022] [Revised: 09/21/2022] [Accepted: 11/02/2022] [Indexed: 12/02/2022] Open
Abstract
Obesity comorbidities such as diabetes and cardiovascular disease are pressing public health concerns. Overconsumption of calories leads to weight gain; however, neural mechanisms underlying excessive food consumption are poorly understood. Here, we demonstrate that dopamine receptor D1 (Drd1) expressed in the agouti-related peptide/neuropeptide Y (AgRP/NPY) neurons of the arcuate hypothalamus is required for appropriate responses to a high-fat diet (HFD). Stimulation of Drd1 and AgRP/NPY co-expressing arcuate neurons is sufficient to induce voracious feeding. Delivery of a HFD after food deprivation acutely induces dopamine (DA) release in the ARC, whereas animals that lack Drd1 expression in ARCAgRP/NPY neurons (Drd1AgRP-KO) exhibit attenuated foraging and refeeding of HFD. These results define a role for the DA input to the ARC that encodes acute responses to food and position Drd1 signaling in the ARCAgRP/NPY neurons as an integrator of the hedonic and homeostatic neuronal feeding circuits.
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Affiliation(s)
- Qi Zhang
- Department of Biology, University of Virginia, Charlottesville, VA 22904, USA
| | - Qijun Tang
- Department of Biology, University of Virginia, Charlottesville, VA 22904, USA
| | - Nidhi M. Purohit
- Department of Biology, University of Virginia, Charlottesville, VA 22904, USA
| | - Julia B. Davenport
- Department of Biology, University of Virginia, Charlottesville, VA 22904, USA
| | - Charles Brennan
- Department of Biology, University of Virginia, Charlottesville, VA 22904, USA
| | - Rahul K. Patel
- Department of Biology, University of Virginia, Charlottesville, VA 22904, USA
| | - Elizabeth Godschall
- Department of Biology, University of Virginia, Charlottesville, VA 22904, USA
| | - Larry S. Zwiefel
- Departments of Pharmacology and Psychiatry and Behavioral Sciences, University of Washington, 1959 NE Pacific Street, Seattle, WA 98195, USA
| | - Anthony Spano
- Department of Biology, University of Virginia, Charlottesville, VA 22904, USA
| | - John N. Campbell
- Department of Biology, University of Virginia, Charlottesville, VA 22904, USA,Program in Fundamental Neuroscience, University of Virginia, Charlottesville, VA 22904, USA
| | - Ali D. Güler
- Department of Biology, University of Virginia, Charlottesville, VA 22904, USA,Program in Fundamental Neuroscience, University of Virginia, Charlottesville, VA 22904, USA,Lead contact,Correspondence:
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32
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Peters KZ, Naneix F. The role of dopamine and endocannabinoid systems in prefrontal cortex development: Adolescence as a critical period. Front Neural Circuits 2022; 16:939235. [PMID: 36389180 PMCID: PMC9663658 DOI: 10.3389/fncir.2022.939235] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2022] [Accepted: 10/14/2022] [Indexed: 01/07/2023] Open
Abstract
The prefrontal cortex plays a central role in the control of complex cognitive processes including action control and decision making. It also shows a specific pattern of delayed maturation related to unique behavioral changes during adolescence and allows the development of adult cognitive processes. The adolescent brain is extremely plastic and critically vulnerable to external insults. Related to this vulnerability, adolescence is also associated with the emergence of numerous neuropsychiatric disorders involving alterations of prefrontal functions. Within prefrontal microcircuits, the dopamine and the endocannabinoid systems have widespread effects on adolescent-specific ontogenetic processes. In this review, we highlight recent advances in our understanding of the maturation of the dopamine system and the endocannabinoid system in the prefrontal cortex during adolescence. We discuss how they interact with GABA and glutamate neurons to modulate prefrontal circuits and how they can be altered by different environmental events leading to long-term neurobiological and behavioral changes at adulthood. Finally, we aim to identify several future research directions to help highlight gaps in our current knowledge on the maturation of these microcircuits.
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Affiliation(s)
- Kate Zara Peters
- Sussex Neuroscience, School of Psychology, University of Sussex, Falmer, United Kingdom
| | - Fabien Naneix
- The Rowett Institute, University of Aberdeen, Aberdeen, United Kingdom,*Correspondence: Fabien Naneix
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33
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Abstract
When it comes to food, one tempting substance is sugar. Although sweetness is detected by the tongue, the desire to consume sugar arises from the gut. Even when sweet taste is impaired, animals can distinguish sugars from non-nutritive sweeteners guided by sensory cues arising from the gut epithelium. Here, we review the molecular receptors, cells, circuits and behavioural consequences associated with sugar sensing in the gut. Recent work demonstrates that some duodenal cells, termed neuropod cells, can detect glucose using sodium-glucose co-transporter 1 and release glutamate onto vagal afferent neurons. Based on these and other data, we propose a model in which specific populations of vagal neurons relay these sensory cues to distinct sets of neurons in the brain, including neurons in the caudal nucleus of the solitary tract, dopaminergic reward circuits in the basal ganglia and homeostatic feeding circuits in the hypothalamus, that alter current and future sugar consumption. This emerging model highlights the critical role of the gut in sensing the chemical properties of ingested nutrients to guide appetitive decisions.
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Affiliation(s)
- Winston W Liu
- Laboratory of Gut Brain Neurobiology, Duke University, Durham, NC, USA
- Department of Medicine, Duke University, Durham, NC, USA
- Department of Neurobiology, Duke University, Durham, NC, USA
| | - Diego V Bohórquez
- Laboratory of Gut Brain Neurobiology, Duke University, Durham, NC, USA.
- Department of Medicine, Duke University, Durham, NC, USA.
- Department of Neurobiology, Duke University, Durham, NC, USA.
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Diet-induced inflammation in the anterior paraventricular thalamus induces compulsive sucrose-seeking. Nat Neurosci 2022; 25:1009-1013. [PMID: 35915173 DOI: 10.1038/s41593-022-01129-y] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2021] [Accepted: 06/22/2022] [Indexed: 11/08/2022]
Abstract
Overconsumption of palatable food may initiate neuroadaptive responses in brain reward circuitry that may contribute to eating disorders. Here we report that high-fat diet (HFD) consumption impedes threat-cue-induced suppression of sucrose-seeking in mice. This compulsive sucrose-seeking was due to enhanced cue-triggered neuronal activity in the anterior paraventricular thalamus (aPVT) resulting from HFD-induced microglia activation. Thus, metabolic inflammation in the aPVT produces an adaptive response to threat cues, leading to compulsive food-seeking.
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35
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Grove JCR, Gray LA, La Santa Medina N, Sivakumar N, Ahn JS, Corpuz TV, Berke JD, Kreitzer AC, Knight ZA. Dopamine subsystems that track internal states. Nature 2022; 608:374-380. [PMID: 35831501 PMCID: PMC9365689 DOI: 10.1038/s41586-022-04954-0] [Citation(s) in RCA: 41] [Impact Index Per Article: 20.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2021] [Accepted: 06/08/2022] [Indexed: 12/11/2022]
Abstract
Food and water are rewarding in part because they satisfy our internal needs1,2. Dopaminergic neurons in the ventral tegmental area (VTA) are activated by gustatory rewards3-5, but how animals learn to associate these oral cues with the delayed physiological effects of ingestion is unknown. Here we show that individual dopaminergic neurons in the VTA respond to detection of nutrients or water at specific stages of ingestion. A major subset of dopaminergic neurons tracks changes in systemic hydration that occur tens of minutes after thirsty mice drink water, whereas different dopaminergic neurons respond to nutrients in the gastrointestinal tract. We show that information about fluid balance is transmitted to the VTA by a hypothalamic pathway and then re-routed to downstream circuits that track the oral, gastrointestinal and post-absorptive stages of ingestion. To investigate the function of these signals, we used a paradigm in which a fluid's oral and post-absorptive effects can be independently manipulated and temporally separated. We show that mice rapidly learn to prefer one fluid over another based solely on its rehydrating ability and that this post-ingestive learning is prevented if dopaminergic neurons in the VTA are selectively silenced after consumption. These findings reveal that the midbrain dopamine system contains subsystems that track different modalities and stages of ingestion, on timescales from seconds to tens of minutes, and that this information is used to drive learning about the consequences of ingestion.
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Affiliation(s)
- James C R Grove
- Department of Physiology, University of California, San Francisco, San Francisco, CA, USA
- Kavli Institute for Fundamental Neuroscience, University of California, San Francisco, San Francisco, CA, USA
- Neuroscience Graduate Program, University of California, San Francisco, San Francisco, CA, USA
| | | | | | | | - Jamie S Ahn
- Howard Hughes Medical Institute, San Francisco, CA, USA
| | | | - Joshua D Berke
- Neuroscience Graduate Program, University of California, San Francisco, San Francisco, CA, USA
- Department of Neurology, University of California, San Francisco, San Francisco, CA, USA
- Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, CA, USA
| | - Anatol C Kreitzer
- Department of Physiology, University of California, San Francisco, San Francisco, CA, USA
- Neuroscience Graduate Program, University of California, San Francisco, San Francisco, CA, USA
- Department of Neurology, University of California, San Francisco, San Francisco, CA, USA
- Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, CA, USA
- Gladstone Institutes, San Francisco, CA, USA
| | - Zachary A Knight
- Department of Physiology, University of California, San Francisco, San Francisco, CA, USA.
- Kavli Institute for Fundamental Neuroscience, University of California, San Francisco, San Francisco, CA, USA.
- Neuroscience Graduate Program, University of California, San Francisco, San Francisco, CA, USA.
- Howard Hughes Medical Institute, San Francisco, CA, USA.
- Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, CA, USA.
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Tang Q, Assali DR, Güler AD, Steele AD. Dopamine systems and biological rhythms: Let's get a move on. Front Integr Neurosci 2022; 16:957193. [PMID: 35965599 PMCID: PMC9364481 DOI: 10.3389/fnint.2022.957193] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2022] [Accepted: 07/06/2022] [Indexed: 02/05/2023] Open
Abstract
How dopamine signaling regulates biological rhythms is an area of emerging interest. Here we review experiments focused on delineating dopamine signaling in the suprachiasmatic nucleus, nucleus accumbens, and dorsal striatum to mediate a range of biological rhythms including photoentrainment, activity cycles, rest phase eating of palatable food, diet-induced obesity, and food anticipatory activity. Enthusiasm for causal roles for dopamine in the regulation of circadian rhythms, particularly those associated with food and other rewarding events, is warranted. However, determining that there is rhythmic gene expression in dopamine neurons and target structures does not mean that they are bona fide circadian pacemakers. Given that dopamine has such a profound role in promoting voluntary movements, interpretation of circadian phenotypes associated with locomotor activity must be differentiated at the molecular and behavioral levels. Here we review our current understanding of dopamine signaling in relation to biological rhythms and suggest future experiments that are aimed at teasing apart the roles of dopamine subpopulations and dopamine receptor expressing neurons in causally mediating biological rhythms, particularly in relation to feeding, reward, and activity.
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Affiliation(s)
- Qijun Tang
- Department of Biology, University of Virginia, Charlottesville, VA, United States
| | - Dina R. Assali
- Department of Biological Sciences, California State Polytechnic University Pomona, Pomona, CA, United States
| | - Ali D. Güler
- Department of Biology, University of Virginia, Charlottesville, VA, United States
- Program in Fundamental Neuroscience, University of Virginia, Charlottesville, VA, United States
- Department of Neuroscience, School of Medicine, University of Virginia, Charlottesville, VA, United States
| | - Andrew D. Steele
- Department of Biological Sciences, California State Polytechnic University Pomona, Pomona, CA, United States
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Chadwick SR, Güler AD. Local Drd1-neurons input to subgroups of arcuate AgRP/NPY-neurons. iScience 2022; 25:104605. [PMID: 35789850 PMCID: PMC9250019 DOI: 10.1016/j.isci.2022.104605] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2021] [Revised: 05/02/2022] [Accepted: 06/08/2022] [Indexed: 11/21/2022] Open
Abstract
Obesity is a pandemic afflicting more than 300 million people worldwide, driven by consumption of calorically dense and highly rewarding foods. Dopamine (DA) signaling has been implicated in neural responses to highly palatable nutrients, but the exact mechanisms through which DA modulates homeostatic feeding circuits remains unknown. A subpopulation of arcuate (ARC) agouti-related peptide (AgRP)/neuropeptide Y (NPY) (ARCAgRP/NPY+) neurons express the D(1A) dopamine receptor (Drd1) and are stimulated by DA, suggesting one potential avenue for dopaminergic regulation of food intake. Using patch clamp electrophysiology, we evaluated the responses of ARC Drd1-expressing (ARCDrd1+) neurons to overnight fasting and leptin. Collectively, ARCDrd1+ neurons were less responsive to caloric deficit than ARCAgRP/NPY+ neurons; however, ARCDrd1+ neurons were inhibited by the satiety hormone leptin. Using Channelrhodopsin-2-Assisted Circuit Mapping, we identified novel subgroups of ARCDrd1+ neurons that inhibit or excite ARCAgRP/NPY+ neurons. These findings suggest dopamine receptive neurons have multimodal actions in food intake circuits.
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Affiliation(s)
- Sean R. Chadwick
- Program in Fundamental Neuroscience and the Department of Biology, University of Virginia, Charlottesville, VA 22904, USA
| | - Ali D. Güler
- Program in Fundamental Neuroscience and the Department of Biology, University of Virginia, Charlottesville, VA 22904, USA
- Department of Neuroscience, School of Medicine, University of Virginia, Charlottesville, VA 22903, USA
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Involvement of the ghrelin system in the maintenance and reinstatement of cocaine-motivated behaviors: a role of adrenergic action at peripheral β1 receptors. Neuropsychopharmacology 2022; 47:1449-1460. [PMID: 34923576 PMCID: PMC9206024 DOI: 10.1038/s41386-021-01249-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/17/2021] [Revised: 11/22/2021] [Accepted: 11/28/2021] [Indexed: 12/30/2022]
Abstract
Cocaine addiction is a significant medical and public concern. Despite decades of research effort, development of pharmacotherapy for cocaine use disorder remains largely unsuccessful. This may be partially due to insufficient understanding of the complex biological mechanisms involved in the pathophysiology of this disorder. In the present study, we show that: (1) elevation of ghrelin by cocaine plays a critical role in maintenance of cocaine self-administration and cocaine-seeking motivated by cocaine-conditioned stimuli; (2) acquisition of cocaine-taking behavior is associated with the acquisition of stimulatory effects of cocaine by cocaine-conditioned stimuli on ghrelin secretion, and with an upregulation of ghrelin receptor mRNA levels in the ventral tegmental area (VTA); (3) blockade of ghrelin signaling by pretreatment with JMV2959, a selective ghrelin receptor antagonist, dose-dependently inhibits reinstatement of cocaine-seeking triggered by either cocaine or yohimbine in behaviorally extinguished animals with a history of cocaine self-administration; (4) JMV2959 pretreatment also inhibits brain stimulation reward (BSR) and cocaine-potentiated BSR maintained by optogenetic stimulation of VTA dopamine neurons in DAT-Cre mice; (5) blockade of peripheral adrenergic β1 receptors by atenolol potently attenuates the elevation in circulating ghrelin induced by cocaine and inhibits cocaine self-administration and cocaine reinstatement triggered by cocaine. These findings demonstrate that the endogenous ghrelin system plays an important role in cocaine-related addictive behaviors and suggest that manipulating and targeting this system may be viable for mitigating cocaine use disorder.
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Morales I. Brain regulation of hunger and motivation: The case for integrating homeostatic and hedonic concepts and its implications for obesity and addiction. Appetite 2022; 177:106146. [PMID: 35753443 DOI: 10.1016/j.appet.2022.106146] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Revised: 06/16/2022] [Accepted: 06/21/2022] [Indexed: 11/19/2022]
Abstract
Obesity and other eating disorders are marked by dysregulations to brain metabolic, hedonic, motivational, and sensory systems that control food intake. Classic approaches in hunger research have distinguished between hedonic and homeostatic processes, and have mostly treated these systems as independent. Hindbrain structures and a complex network of interconnected hypothalamic nuclei control metabolic processes, energy expenditure, and food intake while mesocorticolimbic structures are though to control hedonic and motivational processes associated with food reward. However, it is becoming increasingly clear that hedonic and homeostatic brain systems do not function in isolation, but rather interact as part of a larger network that regulates food intake. Incentive theories of motivation provide a useful route to explore these interactions. Adapting incentive theories of motivation can enable researchers to better how motivational systems dysfunction during disease. Obesity and addiction are associated with profound alterations to both hedonic and homeostatic brain systems that result in maladaptive patterns of consumption. A subset of individuals with obesity may experience pathological cravings for food due to incentive sensitization of brain systems that generate excessive 'wanting' to eat. Further progress in understanding how the brain regulates hunger and appetite may depend on merging traditional hedonic and homeostatic concepts of food reward and motivation.
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Affiliation(s)
- Ileana Morales
- Department of Psychology, University of Michigan, 530 Church Street, Ann Arbor, MI, 48109-1043, USA.
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Pradel K, Drwięga G, Chrobok L, Błasiak T. Racing and Pacing in the Reward System: A Multi-Clock Circadian Control Over Dopaminergic Signalling. Front Physiol 2022; 13:932378. [PMID: 35812323 PMCID: PMC9259884 DOI: 10.3389/fphys.2022.932378] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2022] [Accepted: 06/07/2022] [Indexed: 11/27/2022] Open
Abstract
Level of motivation, responsiveness to rewards and punishment, invigoration of exploratory behaviours, and motor performance are subject to daily fluctuations that emerge from circadian rhythms in neuronal activity of the midbrain’s dopaminergic system. While endogenous circadian rhythms are weak in the ventral tegmental area and substantia nigra pars compacta, daily changes in expression of core clock genes, ion channels, neurotransmitter receptors, dopamine-synthesising enzymes, and dopamine transporters, accompanied by changes in electrical activity, are readily observed in these nuclei. These processes cause dopamine levels released in structures innervated by midbrain dopaminergic neurons (e.g., the striatum) to oscillate in a circadian fashion. Additionally, growing evidence show that the master circadian clock located in the suprachiasmatic nucleus of the hypothalamus (SCN) rhythmically influences the activity of the dopaminergic system through various intermediate targets. Thus, circadian changes in the activity of the dopaminergic system and concomitant dopamine release observed on a daily scale are likely to be generated both intrinsically and entrained by the master clock. Previous studies have shown that the information about the value and salience of stimuli perceived by the animal is encoded in the neuronal activity of brain structures innervating midbrain dopaminergic centres. Some of these structures themselves are relatively autonomous oscillators, while others exhibit a weak endogenous circadian rhythm synchronised by the SCN. Here, we place the dopaminergic system as a hub in the extensive network of extra-SCN circadian oscillators and discuss the possible consequences of its daily entrainment for animal physiology and behaviour.
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Affiliation(s)
- Kamil Pradel
- Department of Neurophysiology and Chronobiology, Institute of Zoology and Biomedical Research, Jagiellonian University, Kraków, Poland
| | - Gniewosz Drwięga
- Department of Neurophysiology and Chronobiology, Institute of Zoology and Biomedical Research, Jagiellonian University, Kraków, Poland
| | - Lukasz Chrobok
- School of Physiology, Pharmacology and Neuroscience, University of Bristol, University Walk, Bristol, United Kingdom
- *Correspondence: Lukasz Chrobok, ; Tomasz Błasiak,
| | - Tomasz Błasiak
- Department of Neurophysiology and Chronobiology, Institute of Zoology and Biomedical Research, Jagiellonian University, Kraków, Poland
- *Correspondence: Lukasz Chrobok, ; Tomasz Błasiak,
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Ghidewon M, Wald H, McKnight AD, De Jonghe BC, Breen DM, Alhadeff AL, Borner T, Grill HJ. Growth differentiation factor 15 (GDF15) and semaglutide inhibit food intake and body weight through largely distinct, additive mechanisms. Diabetes Obes Metab 2022; 24:1010-1020. [PMID: 35129264 PMCID: PMC9796095 DOI: 10.1111/dom.14663] [Citation(s) in RCA: 22] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/26/2021] [Revised: 01/16/2022] [Accepted: 01/30/2022] [Indexed: 12/31/2022]
Abstract
AIMS To evaluate whether the potent hypophagic and weight-suppressive effects of growth differentiation factor-15 (GDF15) and semaglutide combined would be a more efficacious antiobesity treatment than either treatment alone by examining whether the neural and behavioural mechanisms contributing to their anorectic effects were common or disparate. MATERIALS/METHODS Three mechanisms were investigated to determine how GDF15 and semaglutide induce anorexia: the potentiation of the intake suppression by gastrointestinal satiation signals; the reduction in motivation to feed; and the induction of visceral malaise. We then compared the effects of short-term, combined GDF15 and semaglutide treatment on weight loss to the individual treatments. Rat pharmaco-behavioural experiments assessed whether GDF15 or semaglutide added to the satiating effects of orally gavaged food and exogenous cholecystokinin (CCK). A progressive ratio operant paradigm was used to examine whether GDF15 or semaglutide reduced feeding motivation. Pica behaviour (ie, kaolin intake) and conditioned affective food aversion testing were used to evaluate visceral malaise. Additionally, fibre photometry studies were conducted in agouti-related protein (AgRP)-Cre mice to examine whether GDF15 or semaglutide, alone or in combination with CCK, modulate calcium signalling in hypothalamic AgRP neurons. RESULTS Semaglutide reduced food intake by amplifying the feeding-inhibitory effect of CCK or ingested food, inhibited the activity of AgRP neurons when combined with CCK, reduced feeding motivation and induced malaise. GDF15 induced visceral malaise but, strikingly, did not affect feeding motivation, the satiating effect of ingested food or CCK signal processing. Combined GDF15 and semaglutide treatment produced greater food intake and body weight suppression than did either treatment alone, without enhancing malaise. CONCLUSIONS GDF15 and semaglutide reduce food intake and body weight through largely distinct processes that produce greater weight loss and feeding suppression when combined.
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Affiliation(s)
- M. Ghidewon
- Institute of Diabetes, Obesity and Metabolism and School of Arts and Sciences, University of Pennsylvania, Philadelphia, Pennsylvania
- Department of Neuroscience, University of Pennsylvania, Philadelphia, Pennsylvania
| | - H.S. Wald
- Institute of Diabetes, Obesity and Metabolism and School of Arts and Sciences, University of Pennsylvania, Philadelphia, Pennsylvania
| | - A. D. McKnight
- Department of Neuroscience, University of Pennsylvania, Philadelphia, Pennsylvania
- Monell Chemical Senses Center, Philadelphia, Pennsylvania
| | - B. C. De Jonghe
- Department of Biobehavioral Health Sciences, School of Nursing, University of Pennsylvania, Philadelphia, Pennsylvania
- Department of Psychiatry, University of Pennsylvania, Perelman School of Medicine, Philadelphia, Pennsylvania
| | - D. M. Breen
- Internal Medicine Research Unit, Pfizer Global R&D, Cambridge, Massachusetts
| | - A. L. Alhadeff
- Department of Neuroscience, University of Pennsylvania, Philadelphia, Pennsylvania
- Monell Chemical Senses Center, Philadelphia, Pennsylvania
| | - T. Borner
- Department of Biobehavioral Health Sciences, School of Nursing, University of Pennsylvania, Philadelphia, Pennsylvania
- Department of Psychiatry, University of Pennsylvania, Perelman School of Medicine, Philadelphia, Pennsylvania
| | - H. J. Grill
- Institute of Diabetes, Obesity and Metabolism and School of Arts and Sciences, University of Pennsylvania, Philadelphia, Pennsylvania
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Wu Z, Lin D, Li Y. Pushing the frontiers: tools for monitoring neurotransmitters and neuromodulators. Nat Rev Neurosci 2022; 23:257-274. [PMID: 35361961 PMCID: PMC11163306 DOI: 10.1038/s41583-022-00577-6] [Citation(s) in RCA: 79] [Impact Index Per Article: 39.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/21/2022] [Indexed: 12/26/2022]
Abstract
Neurotransmitters and neuromodulators have a wide range of key roles throughout the nervous system. However, their dynamics in both health and disease have been challenging to assess, owing to the lack of in vivo tools to track them with high spatiotemporal resolution. Thus, developing a platform that enables minimally invasive, large-scale and long-term monitoring of neurotransmitters and neuromodulators with high sensitivity, high molecular specificity and high spatiotemporal resolution has been essential. Here, we review the methods available for monitoring the dynamics of neurotransmitters and neuromodulators. Following a brief summary of non-genetically encoded methods, we focus on recent developments in genetically encoded fluorescent indicators, highlighting how these novel indicators have facilitated advances in our understanding of the functional roles of neurotransmitters and neuromodulators in the nervous system. These studies present a promising outlook for the future development and use of tools to monitor neurotransmitters and neuromodulators.
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Affiliation(s)
- Zhaofa Wu
- State Key Laboratory of Membrane Biology, Peking University School of Life Sciences, Beijing, China
- PKU-IDG/McGovern Institute for Brain Research, Beijing, China
| | - Dayu Lin
- Neuroscience Institute, New York University Grossman School of Medicine, New York, NY, USA
- Department of Psychiatry, New York University Grossman School of Medicine, New York, NY, USA
| | - Yulong Li
- State Key Laboratory of Membrane Biology, Peking University School of Life Sciences, Beijing, China.
- PKU-IDG/McGovern Institute for Brain Research, Beijing, China.
- Peking-Tsinghua Center for Life Sciences, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, China.
- Chinese Institute for Brain Research, Beijing, China.
- Institute of Molecular Physiology, Shenzhen Bay Laboratory, Shenzhen, China.
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43
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Hall KD, Farooqi IS, Friedman JM, Klein S, Loos RJF, Mangelsdorf DJ, O'Rahilly S, Ravussin E, Redman LM, Ryan DH, Speakman JR, Tobias DK. The energy balance model of obesity: beyond calories in, calories out. Am J Clin Nutr 2022; 115:1243-1254. [PMID: 35134825 DOI: 10.1093/ajcn/nqac031%jtheamericanjournalofclinicalnutrition] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2021] [Accepted: 02/02/2022] [Indexed: 05/25/2023] Open
Abstract
A recent Perspective article described the "carbohydrate-insulin model (CIM)" of obesity, asserting that it "better reflects knowledge on the biology of weight control" as compared with what was described as the "dominant energy balance model (EBM)," which fails to consider "biological mechanisms that promote weight gain." Unfortunately, the Perspective conflated and confused the principle of energy balance, a law of physics that is agnostic as to obesity mechanisms, with the EBM as a theoretical model of obesity that is firmly based on biology. In doing so, the authors presented a false choice between the CIM and a caricature of the EBM that does not reflect modern obesity science. Here, we present a more accurate description of the EBM where the brain is the primary organ responsible for body weight regulation operating mainly below our conscious awareness via complex endocrine, metabolic, and nervous system signals to control food intake in response to the body's dynamic energy needs as well as environmental influences. We also describe the recent history of the CIM and show how the latest "most comprehensive formulation" abandons a formerly central feature that required fat accumulation in adipose tissue to be the primary driver of positive energy balance. As such, the new CIM can be considered a special case of the more comprehensive EBM but with a narrower focus on diets high in glycemic load as the primary factor responsible for common obesity. We review data from a wide variety of studies that address the validity of each model and demonstrate that the EBM is a more robust theory of obesity than the CIM.
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Affiliation(s)
- Kevin D Hall
- National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health
| | - I Sadaf Farooqi
- Wellcome-MRC Institute of Metabolic Science, University of Cambridge
| | | | - Samuel Klein
- Washington University School of Medicine in St Louis
| | - Ruth J F Loos
- Washington University School of Medicine in St Louis
- Novo Nordisk Foundation Center for Basic Metabolic Research, University of Copenhagen
| | | | - Stephen O'Rahilly
- Wellcome-MRC Institute of Metabolic Science, University of Cambridge
| | | | | | | | - John R Speakman
- Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzen, China, and the University of Aberdeen, Aberdeen, United Kingdom
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Hall KD, Farooqi IS, Friedman JM, Klein S, Loos RJF, Mangelsdorf DJ, O'Rahilly S, Ravussin E, Redman LM, Ryan DH, Speakman JR, Tobias DK. The energy balance model of obesity: beyond calories in, calories out. Am J Clin Nutr 2022; 115:1243-1254. [PMID: 35134825 PMCID: PMC9071483 DOI: 10.1093/ajcn/nqac031] [Citation(s) in RCA: 120] [Impact Index Per Article: 60.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2021] [Accepted: 02/02/2022] [Indexed: 02/06/2023] Open
Abstract
A recent Perspective article described the "carbohydrate-insulin model (CIM)" of obesity, asserting that it "better reflects knowledge on the biology of weight control" as compared with what was described as the "dominant energy balance model (EBM)," which fails to consider "biological mechanisms that promote weight gain." Unfortunately, the Perspective conflated and confused the principle of energy balance, a law of physics that is agnostic as to obesity mechanisms, with the EBM as a theoretical model of obesity that is firmly based on biology. In doing so, the authors presented a false choice between the CIM and a caricature of the EBM that does not reflect modern obesity science. Here, we present a more accurate description of the EBM where the brain is the primary organ responsible for body weight regulation operating mainly below our conscious awareness via complex endocrine, metabolic, and nervous system signals to control food intake in response to the body's dynamic energy needs as well as environmental influences. We also describe the recent history of the CIM and show how the latest "most comprehensive formulation" abandons a formerly central feature that required fat accumulation in adipose tissue to be the primary driver of positive energy balance. As such, the new CIM can be considered a special case of the more comprehensive EBM but with a narrower focus on diets high in glycemic load as the primary factor responsible for common obesity. We review data from a wide variety of studies that address the validity of each model and demonstrate that the EBM is a more robust theory of obesity than the CIM.
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Affiliation(s)
- Kevin D Hall
- National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health
| | - I Sadaf Farooqi
- Wellcome-MRC Institute of Metabolic Science, University of Cambridge
| | | | - Samuel Klein
- Washington University School of Medicine in St Louis
| | - Ruth J F Loos
- Washington University School of Medicine in St Louis.,Novo Nordisk Foundation Center for Basic Metabolic Research, University of Copenhagen
| | | | - Stephen O'Rahilly
- Wellcome-MRC Institute of Metabolic Science, University of Cambridge
| | | | | | | | - John R Speakman
- Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzen, China, and the University of Aberdeen, Aberdeen, United Kingdom
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Chen L, Wu H, Li Y, Feng X, Zhu S, Xie K, Wu X, Sun Z, Shu G, Wang S, Gao P, Zhu X, Zhu C, Jiang Q, Wang L. Corticotropin-releasing factor receptor type 2 in the midbrain critically contributes to the hedonic feeding behavior of mice under heat stress. Biochem Biophys Res Commun 2022; 602:77-83. [DOI: 10.1016/j.bbrc.2022.02.109] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2021] [Revised: 01/23/2022] [Accepted: 02/26/2022] [Indexed: 11/26/2022]
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46
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Brain circuits for promoting homeostatic and non-homeostatic appetites. Exp Mol Med 2022; 54:349-357. [PMID: 35474340 PMCID: PMC9076862 DOI: 10.1038/s12276-022-00758-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2021] [Revised: 02/24/2022] [Accepted: 03/07/2022] [Indexed: 11/28/2022] Open
Abstract
As the principal means of acquiring nutrients, feeding behavior is indispensable to the survival and well-being of animals. In response to energy or nutrient deficits, animals seek and consume food to maintain energy homeostasis. On the other hand, even when animals are calorically replete, non-homeostatic factors, such as the sight, smell, and taste of palatable food, or environmental cues that predict food, can stimulate feeding behavior. These homeostatic and non-homeostatic factors have traditionally been investigated separately, but a growing body of literature highlights that these factors work synergistically to promote feeding behavior. Furthermore, recent breakthroughs in cell type-specific and circuit-specific labeling, recording, and manipulation techniques have markedly accelerated the discovery of well-defined neural populations underlying homeostatic and non-homeostatic appetite control, as well as overlapping circuits that contribute to both types of appetite. This review aims to provide an update on our understanding of the neural circuit mechanisms for promoting homeostatic and non-homeostatic appetites, focusing on the function of recently identified, genetically defined cell types. Research on the neural circuit mechanisms underlying feeding behaviors is critical to identifying therapeutic targets for food-related disorders like obesity and anorexia. Sung-Yon Kim and colleagues at Seoul National University, South Korea, reviewed the current understanding of neural circuits promoting feeding behavior, which is regulated by homeostatic and non-homeostatic appetites. In response to deficits in energy (caloric) or nutrients, specific populations of neurons sensitive to hormones leptin and ghrelin generate homeostatic appetite and promote feeding. In addition, diverse neural populations stimulate non-homeostatic appetite in the absence of immediate internal needs and are thought to drive overconsumption in the modern obesogenic environment. These appetites extensively interact through overlapping neural circuits to jointly promote feeding behaviors.
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Berland C, Castel J, Terrasi R, Montalban E, Foppen E, Martin C, Muccioli GG, Luquet S, Gangarossa G. Identification of an endocannabinoid gut-brain vagal mechanism controlling food reward and energy homeostasis. Mol Psychiatry 2022; 27:2340-2354. [PMID: 35075269 DOI: 10.1038/s41380-021-01428-z] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/14/2021] [Revised: 12/07/2021] [Accepted: 12/23/2021] [Indexed: 12/11/2022]
Abstract
The regulation of food intake, a sine qua non requirement for survival, thoroughly shapes feeding and energy balance by integrating both homeostatic and hedonic values of food. Unfortunately, the widespread access to palatable food has led to the development of feeding habits that are independent from metabolic needs. Among these, binge eating (BE) is characterized by uncontrolled voracious eating. While reward deficit seems to be a major contributor of BE, the physiological and molecular underpinnings of BE establishment remain elusive. Here, we combined a physiologically relevant BE mouse model with multiscale in vivo approaches to explore the functional connection between the gut-brain axis and the reward and homeostatic brain structures. Our results show that BE elicits compensatory adaptations requiring the gut-to-brain axis which, through the vagus nerve, relies on the permissive actions of peripheral endocannabinoids (eCBs) signaling. Selective inhibition of peripheral CB1 receptors resulted in a vagus-dependent increased hypothalamic activity, modified metabolic efficiency, and dampened activity of mesolimbic dopamine circuit, altogether leading to the suppression of palatable eating. We provide compelling evidence for a yet unappreciated physiological integrative mechanism by which variations of peripheral eCBs control the activity of the vagus nerve, thereby in turn gating the additive responses of both homeostatic and hedonic brain circuits which govern homeostatic and reward-driven feeding. In conclusion, we reveal that vagus-mediated eCBs/CB1R functions represent an interesting and innovative target to modulate energy balance and counteract food-reward disorders.
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Affiliation(s)
- Chloé Berland
- Université de Paris, CNRS, Unité de Biologie Fonctionnelle et Adaptative, F-75013, Paris, France
| | - Julien Castel
- Université de Paris, CNRS, Unité de Biologie Fonctionnelle et Adaptative, F-75013, Paris, France
| | - Romano Terrasi
- Bioanalysis and Pharmacology of Bioactive Lipids Research Group, Louvain Drug Research Institute, Université catholique de Louvain, 1200, Brussels, Belgium
| | - Enrica Montalban
- Université de Paris, CNRS, Unité de Biologie Fonctionnelle et Adaptative, F-75013, Paris, France
| | - Ewout Foppen
- Université de Paris, CNRS, Unité de Biologie Fonctionnelle et Adaptative, F-75013, Paris, France
| | - Claire Martin
- Université de Paris, CNRS, Unité de Biologie Fonctionnelle et Adaptative, F-75013, Paris, France
| | - Giulio G Muccioli
- Bioanalysis and Pharmacology of Bioactive Lipids Research Group, Louvain Drug Research Institute, Université catholique de Louvain, 1200, Brussels, Belgium
| | - Serge Luquet
- Université de Paris, CNRS, Unité de Biologie Fonctionnelle et Adaptative, F-75013, Paris, France
| | - Giuseppe Gangarossa
- Université de Paris, CNRS, Unité de Biologie Fonctionnelle et Adaptative, F-75013, Paris, France.
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48
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Goldstein N, Carty JRE, Betley JN. Specificity of Varenicline in Blocking Mesolimbic Circuit Activation to Natural and Drug Rewards. Neuroscience 2022; 483:40-51. [PMID: 34923039 PMCID: PMC8837713 DOI: 10.1016/j.neuroscience.2021.12.016] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2021] [Revised: 12/09/2021] [Accepted: 12/10/2021] [Indexed: 12/21/2022]
Abstract
The mesolimbic dopamine (DA) system reinforces behaviors that are critical for survival. However, drug dependence can occur when drugs of abuse, such as nicotine, highjack this reinforcement system. Pharmacologically targeting the DA system to selectively block drug reinforcement requires a detailed understanding of the neural circuits and molecular pathways that lead to the reward-based activation of mesolimbic circuits. Varenicline is an approved smoking cessation drug that has been shown to block nicotine-evoked DA increases in the nucleus accumbens (NAc) through action on nicotinic acetylcholine receptors. Because these receptors have been implicated in the reinforcement of other addictive substances, we explored the possibility that varenicline could broadly affect reward processing. We used in vivo fiber photometry to monitor midbrain DA neuron activity and striatal DA levels following either natural or drug rewards in mice treated with varenicline. We demonstrate that varenicline pretreatment enhances the suppression of nicotine-evoked DA release by attenuating DA neuron activity in the VTA. Varenicline's ability to attenuate DA release is highly specific to nicotine, and varenicline slightly elevates DA release when co-administered with morphine or ethanol. Furthermore, varenicline has no effect on DA release in response to naturally rewarding behavior such as food intake or exercise. These results demonstrate the exquisite specificity with which varenicline blocks nicotine reward and highlight the complexity with which different rewards activate the mesolimbic DA system.
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Affiliation(s)
- Nitsan Goldstein
- Department of Biology, University of Pennsylvania, Philadelphia, PA 19104, United States
| | - Jamie R E Carty
- Department of Biology, University of Pennsylvania, Philadelphia, PA 19104, United States
| | - J Nicholas Betley
- Department of Biology, University of Pennsylvania, Philadelphia, PA 19104, United States.
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49
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Nelson NG, Wu L, Maier MT, Lam D, Cheang R, Alba D, Huang A, Neumann DA, Hill T, Vagena E, Barsh GS, Medina MW, Krauss RM, Koliwad SK, Xu AW. A gene-diet interaction controlling relative intake of dietary carbohydrates and fats. Mol Metab 2022; 58:101442. [PMID: 35051651 PMCID: PMC9710720 DOI: 10.1016/j.molmet.2022.101442] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/03/2021] [Revised: 01/04/2022] [Accepted: 01/10/2022] [Indexed: 12/15/2022] Open
Abstract
OBJECTIVE Preference for dietary fat vs. carbohydrate varies markedly across free-living individuals. It is recognized that food choice is under genetic and physiological regulation, and that the central melanocortin system is involved. However, how genetic and dietary factors interact to regulate relative macronutrient intake is not well understood. METHODS We investigated how the choice for food rich in carbohydrate vs. fat is influenced by dietary cholesterol availability and agouti-related protein (AGRP), the orexigenic component of the central melanocortin system. We assessed how macronutrient intake and different metabolic parameters correlate with plasma AGRP in a cohort of obese humans. We also examined how both dietary cholesterol levels and inhibiting de novo cholesterol synthesis affect carbohydrate and fat intake in mice, and how dietary cholesterol deficiency during the postnatal period impacts macronutrient intake patterns in adulthood. RESULTS In obese human subjects, plasma levels of AGRP correlated inversely with consumption of carbohydrates over fats. Moreover, AgRP-deficient mice preferred to consume more calories from carbohydrates than fats, more so when each diet lacked cholesterol. Intriguingly, inhibiting cholesterol biosynthesis (simvastatin) promoted carbohydrate intake at the expense of fat without altering total caloric consumption, an effect that was remarkably absent in AgRP-deficient mice. Finally, feeding lactating C57BL/6 dams and pups a cholesterol-free diet prior to weaning led the offspring to prefer fats over carbohydrates as adults, indicating that altered cholesterol metabolism early in life programs adaptive changes to macronutrient intake. CONCLUSIONS Together, our study illustrates a specific gene-diet interaction in modulating food choice.
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Affiliation(s)
- Nnamdi G. Nelson
- Diabetes Center, University of California, San Francisco, San Francisco,
CA 94143, USA
| | - Lili Wu
- Diabetes Center, University of California, San Francisco, San Francisco,
CA 94143, USA,Department of Integrated Medicine, Guangxi Medical University Cancer
Hospital, Nanning, Guangxi 530021, China
| | - Matthew T. Maier
- Diabetes Center, University of California, San Francisco, San Francisco,
CA 94143, USA
| | - Diana Lam
- Diabetes Center, University of California, San Francisco, San Francisco,
CA 94143, USA
| | - Rachel Cheang
- Diabetes Center, University of California, San Francisco, San Francisco,
CA 94143, USA
| | - Diana Alba
- Diabetes Center, University of California, San Francisco, San Francisco,
CA 94143, USA,Department of Medicine, University of California, San Francisco, San
Francisco, CA 94143, USA
| | - Alyssa Huang
- Diabetes Center, University of California, San Francisco, San Francisco,
CA 94143, USA,Department of Pediatrics, University of California, San Francisco, San
Francisco, CA 94143, USA
| | - Drexel A. Neumann
- Diabetes Center, University of California, San Francisco, San Francisco,
CA 94143, USA
| | - Tess Hill
- Diabetes Center, University of California, San Francisco, San Francisco,
CA 94143, USA
| | - Eirini Vagena
- Diabetes Center, University of California, San Francisco, San Francisco,
CA 94143, USA
| | - Gregory S. Barsh
- Department of Genetics, Stanford University School of Medicine, Stanford,
CA 94305, USA
| | - Marisa W. Medina
- Department of Pediatrics, University of California, San Francisco, San
Francisco, CA 94143, USA
| | - Ronald M. Krauss
- Department of Medicine, University of California, San Francisco, San
Francisco, CA 94143, USA,Department of Pediatrics, University of California, San Francisco, San
Francisco, CA 94143, USA
| | - Suneil K. Koliwad
- Diabetes Center, University of California, San Francisco, San Francisco,
CA 94143, USA,Department of Medicine, University of California, San Francisco, San
Francisco, CA 94143, USA,Corresponding author. Diabetes Center, University of California, San
Francisco, San Francisco, CA 94143, USA.
| | - Allison W. Xu
- Diabetes Center, University of California, San Francisco, San Francisco,
CA 94143, USA,Department of Anatomy, University of California, San Francisco, San
Francisco, CA 94143, USA,Corresponding author. Diabetes Center, University of California, San
Francisco, San Francisco, CA 94143, USA.
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50
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Reichenbach A, Clarke RE, Stark R, Lockie SH, Mequinion M, Dempsey H, Rawlinson S, Reed F, Sepehrizadeh T, DeVeer M, Munder AC, Nunez-Iglesias J, Spanswick D, Mynatt R, Kravitz AV, Dayas CV, Brown R, Andrews ZB. Metabolic sensing in AgRP neurons integrates homeostatic state with dopamine signalling in the striatum. eLife 2022; 11:72668. [PMID: 35018884 PMCID: PMC8803314 DOI: 10.7554/elife.72668] [Citation(s) in RCA: 22] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2021] [Accepted: 01/11/2022] [Indexed: 11/17/2022] Open
Abstract
Agouti-related peptide (AgRP) neurons increase motivation for food, however, whether metabolic sensing of homeostatic state in AgRP neurons potentiates motivation by interacting with dopamine reward systems is unexplored. As a model of impaired metabolic-sensing, we used the AgRP-specific deletion of carnitine acetyltransferase (Crat) in mice. We hypothesised that metabolic sensing in AgRP neurons is required to increase motivation for food reward by modulating accumbal or striatal dopamine release. Studies confirmed that Crat deletion in AgRP neurons (KO) impaired ex vivo glucose-sensing, as well as in vivo responses to peripheral glucose injection or repeated palatable food presentation and consumption. Impaired metabolic-sensing in AgRP neurons reduced acute dopamine release (seconds) to palatable food consumption and during operant responding, as assessed by GRAB-DA photometry in the nucleus accumbens, but not the dorsal striatum. Impaired metabolic-sensing in AgRP neurons suppressed radiolabelled 18F-fDOPA accumulation after ~30 min in the dorsal striatum but not the nucleus accumbens. Impaired metabolic sensing in AgRP neurons suppressed motivated operant responding for sucrose rewards during fasting. Thus, metabolic-sensing in AgRP neurons is required for the appropriate temporal integration and transmission of homeostatic hunger-sensing to dopamine signalling in the striatum.
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Affiliation(s)
| | - Rachel E Clarke
- Department of Physiology, Monash University, Clayton, Australia
| | - Romana Stark
- Department of Physiology, Monash University, Clayton, Australia
| | - Sarah H Lockie
- Department of Physiology, Monash University, Clayton, Australia
| | | | - Harry Dempsey
- Department of Physiology, Monash University, Clayton, Australia
| | - Sasha Rawlinson
- Department of Physiology, Monash University, Clayton, Australia
| | - Felicia Reed
- Department of Physiology, Monash University, Clayton, Australia
| | - Tara Sepehrizadeh
- Monash Biomedical Imaging Facility, Monash University, Clayton, Australia
| | - Michael DeVeer
- Monash Biomedical Imaging Facility, Monash University, Clayton, Australia
| | - Astrid C Munder
- Department of Physiology, Monash University, Clayton, Australia
| | - Juan Nunez-Iglesias
- Department of Anatomy and Developmental Biology, Monash University, Clayton, Australia
| | - David Spanswick
- Department of Physiology, Monash University, Clayton, Australia
| | - Randall Mynatt
- Gene Nutrient Interactions Laboratory, Pennington Biomedical Research Center, Baton Rouge, United States
| | - Alexxai V Kravitz
- Departments of Psychiatry, Washington University in St. Louis, Saint Louis, United States
| | - Christopher V Dayas
- School of Biomedical Sciences and Pharmacy, University of Newcastle, Callaghan, Australia
| | - Robyn Brown
- Department of Biochemistry and Pharmacology, University of Melbourne, Parkville, Australia
| | - Zane B Andrews
- Department of Physiology, Monash University, Clayton, Australia
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