1
|
Spencer CD, Miller PA, Williams-Ikhenoba JG, Nikolova RG, Chee MJ. Regulation of the Mouse Ventral Tegmental Area by Melanin-Concentrating Hormone. J Neurosci 2024; 44:e0790232024. [PMID: 38806249 PMCID: PMC11223476 DOI: 10.1523/jneurosci.0790-23.2024] [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: 04/30/2023] [Revised: 05/02/2024] [Accepted: 05/15/2024] [Indexed: 05/30/2024] Open
Abstract
Melanin-concentrating hormone (MCH) acts via its sole receptor MCHR1 in rodents and is an important regulator of homeostatic behaviors like feeding, sleep, and mood to impact overall energy balance. The loss of MCH signaling by MCH or MCHR1 deletion produces hyperactive mice with increased energy expenditure, and these effects are consistently associated with a hyperdopaminergic state. We recently showed that MCH suppresses dopamine release in the nucleus accumbens, which principally receives dopaminergic projections from the ventral tegmental area (VTA), but the mechanisms underlying MCH-regulated dopamine release are not clearly defined. MCHR1 expression is widespread and includes dopaminergic VTA cells. However, as the VTA is a neurochemically diverse structure, we assessed Mchr1 gene expression at glutamatergic, GABAergic, and dopaminergic VTA cells and determined if MCH inhibited the activity of VTA cells and/or their local microcircuit. Mchr1 expression was robust in major VTA cell types, including most dopaminergic (78%) or glutamatergic cells (52%) and some GABAergic cells (38%). Interestingly, MCH directly inhibited dopaminergic and GABAergic cells but did not regulate the activity of glutamatergic cells. Rather, MCH produced a delayed increase in excitatory input to dopamine cells and a corresponding decrease in GABAergic input to glutamatergic VTA cells. Our findings suggested that MCH may acutely suppress dopamine release while disinhibiting local glutamatergic signaling to restore dopamine levels. This indicated that the VTA is a target of MCH action, which may provide bidirectional regulation of energy balance.
Collapse
Affiliation(s)
- Carl Duncan Spencer
- Department of Neuroscience, Carleton University, Ottawa, Ontario K1S 5B6, Canada
| | - Persephone A Miller
- Department of Neuroscience, Carleton University, Ottawa, Ontario K1S 5B6, Canada
| | | | - Ralitsa G Nikolova
- Department of Neuroscience, Carleton University, Ottawa, Ontario K1S 5B6, Canada
| | - Melissa J Chee
- Department of Neuroscience, Carleton University, Ottawa, Ontario K1S 5B6, Canada
| |
Collapse
|
2
|
Payant MA, Spencer CD, Ly NKK, Chee MJ. Inhibitory actions of melanin-concentrating hormone in the lateral septum. J Physiol 2024. [PMID: 38874572 DOI: 10.1113/jp284845] [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: 04/11/2023] [Accepted: 05/21/2024] [Indexed: 06/15/2024] Open
Abstract
Melanin-concentrating hormone (MCH) neurons can co-express several neuropeptides or neurotransmitters and send widespread projections throughout the brain. Notably, there is a dense cluster of nerve terminals from MCH neurons in the lateral septum (LS) that innervate LS cells by glutamate release. The LS is also a key region integrating stress- and anxiety-like behaviours, which are also emerging roles of MCH neurons. However, it is not known if or where the MCH peptide acts within the LS. We analysed the projections from MCH neurons in male and female mice anteroposteriorly throughout the LS and found spatial overlap between the distribution pattern of MCH-immunoreactive (MCH-ir) fibres with MCH receptor Mchr1 mRNA hybridization or MCHR1-ir cells. This overlap was most prominent along the ventral and lateral border of the rostral part of the LS (LSr). Most MCHR1-labelled LS neurons lay adjacent to passing MCH-ir fibres, but some MCH-ir varicosities directly contacted the soma or cilium of MCHR1-labelled LS neurons. We thus performed whole-cell patch-clamp recordings from MCHR1-rich LSr regions to determine if and how LS cells respond to MCH. Bath application of MCH to acute brain slices activated a bicuculline-sensitive chloride current that directly hyperpolarized LS cells. This MCH-mediated hyperpolarization was blocked by calphostin C, which suggested that the inhibitory actions of MCH were mediated by protein kinase C-dependent activation of GABAA receptors. Taken together, these findings define potential hotspots within the LS that may elucidate the contributions of MCH to stress- or anxiety-related feeding behaviours. KEY POINTS: Melanin-concentrating hormone (MCH) neurons have dense nerve terminals within the lateral septum (LS), a key region underlying stress- and anxiety-like behaviours that are emerging roles of the MCH system, but the function of MCH in the LS is not known. We found spatial overlap between MCH-immunoreactive fibres, Mchr1 mRNA, and MCHR1 protein expression along the lateral border of the LS. Within MCHR1-rich regions, MCH directly inhibited LS cells by increasing chloride conductance via GABAA receptor activation in a protein kinase C-dependent manner. Electrophysiological MCH effects in brain slices have been elusive, and few studies have described the mechanisms of MCH action. Our findings demonstrated, to our knowledge, the first description of MCHR1 Gq-coupling in brain slices, which was previously predicted in cell or primary culture models only. Together, these findings defined hotspots and mechanistic underpinnings for MCH effects such as in feeding and anxiety-related behaviours.
Collapse
Affiliation(s)
- Mikayla A Payant
- Department of Neuroscience, Carleton University, Ottawa, Ontario, Canada
| | - C Duncan Spencer
- Department of Neuroscience, Carleton University, Ottawa, Ontario, Canada
| | - Nikita K Koziel Ly
- Department of Neuroscience, Carleton University, Ottawa, Ontario, Canada
| | - Melissa J Chee
- Department of Neuroscience, Carleton University, Ottawa, Ontario, Canada
| |
Collapse
|
3
|
Jin R, Sun S, Hu Y, Zhang H, Sun X. Neuropeptides Modulate Feeding via the Dopamine Reward Pathway. Neurochem Res 2023:10.1007/s11064-023-03954-4. [PMID: 37233918 DOI: 10.1007/s11064-023-03954-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2023] [Revised: 05/13/2023] [Accepted: 05/16/2023] [Indexed: 05/27/2023]
Abstract
Dopamine (DA) is a catecholamine neurotransmitter widely distributed in the central nervous system. It participates in various physiological functions, such as feeding, anxiety, fear, sleeping and arousal. The regulation of feeding is exceptionally complex, involving energy homeostasis and reward motivation. The reward system comprises the ventral tegmental area (VTA), nucleus accumbens (NAc), hypothalamus, and limbic system. This paper illustrates the detailed mechanisms of eight typical orexigenic and anorexic neuropeptides that regulate food intake through the reward system. According to recent literature, neuropeptides released from the hypothalamus and other brain regions regulate reward feeding predominantly through dopaminergic neurons projecting from the VTA to the NAc. In addition, their effect on the dopaminergic system is mediated by the prefrontal cortex, paraventricular thalamus, laterodorsal tegmental area, amygdala, and complex neural circuits. Research on neuropeptides involved in reward feeding can help identify more targets to treat diseases with metabolic disorders, such as obesity.
Collapse
Affiliation(s)
- Ruijie Jin
- Department of Physiology and Pathophysiology, School of Basic Medicine, Qingdao University, Qingdao, Shandong, China
- Department of Clinical Medicine, Medical College, Qingdao University, Qingdao, China
| | - Shanbin Sun
- Department of Physiology and Pathophysiology, School of Basic Medicine, Qingdao University, Qingdao, Shandong, China
- Department of Clinical Medicine, Medical College, Qingdao University, Qingdao, China
| | - Yang Hu
- Department of Physiology and Pathophysiology, School of Basic Medicine, Qingdao University, Qingdao, Shandong, China
- Department of Clinical Medicine, Medical College, Qingdao University, Qingdao, China
| | - Hongfei Zhang
- Department of Physiology and Pathophysiology, School of Basic Medicine, Qingdao University, Qingdao, Shandong, China
- Department of Clinical Medicine, Medical College, Qingdao University, Qingdao, China
| | - Xiangrong Sun
- Department of Physiology and Pathophysiology, School of Basic Medicine, Qingdao University, Qingdao, Shandong, China.
| |
Collapse
|
4
|
Calafate S, Özturan G, Thrupp N, Vanderlinden J, Santa-Marinha L, Morais-Ribeiro R, Ruggiero A, Bozic I, Rusterholz T, Lorente-Echeverría B, Dias M, Chen WT, Fiers M, Lu A, Vlaeminck I, Creemers E, Craessaerts K, Vandenbempt J, van Boekholdt L, Poovathingal S, Davie K, Thal DR, Wierda K, Oliveira TG, Slutsky I, Adamantidis A, De Strooper B, de Wit J. Early alterations in the MCH system link aberrant neuronal activity and sleep disturbances in a mouse model of Alzheimer's disease. Nat Neurosci 2023:10.1038/s41593-023-01325-4. [PMID: 37188873 DOI: 10.1038/s41593-023-01325-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2022] [Accepted: 04/10/2023] [Indexed: 05/17/2023]
Abstract
Early Alzheimer's disease (AD) is associated with hippocampal hyperactivity and decreased sleep quality. Here we show that homeostatic mechanisms transiently counteract the increased excitatory drive to CA1 neurons in AppNL-G-F mice, but that this mechanism fails in older mice. Spatial transcriptomics analysis identifies Pmch as part of the adaptive response in AppNL-G-F mice. Pmch encodes melanin-concentrating hormone (MCH), which is produced in sleep-active lateral hypothalamic neurons that project to CA1 and modulate memory. We show that MCH downregulates synaptic transmission, modulates firing rate homeostasis in hippocampal neurons and reverses the increased excitatory drive to CA1 neurons in AppNL-G-F mice. AppNL-G-F mice spend less time in rapid eye movement (REM) sleep. AppNL-G-F mice and individuals with AD show progressive changes in morphology of CA1-projecting MCH axons. Our findings identify the MCH system as vulnerable in early AD and suggest that impaired MCH-system function contributes to aberrant excitatory drive and sleep defects, which can compromise hippocampus-dependent functions.
Collapse
Affiliation(s)
- Sara Calafate
- VIB Center for Brain & Disease Research, Leuven, Belgium.
- KU Leuven, Department of Neurosciences, Leuven Brain Institute, Leuven, Belgium.
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, Braga, Portugal.
- ICVS/3B's - PT Government Associate Laboratory, Braga/Guimarães, Portugal.
| | - Gökhan Özturan
- VIB Center for Brain & Disease Research, Leuven, Belgium
- KU Leuven, Department of Neurosciences, Leuven Brain Institute, Leuven, Belgium
| | - Nicola Thrupp
- VIB Center for Brain & Disease Research, Leuven, Belgium
- KU Leuven, Department of Neurosciences, Leuven Brain Institute, Leuven, Belgium
| | - Jeroen Vanderlinden
- VIB Center for Brain & Disease Research, Leuven, Belgium
- KU Leuven, Department of Neurosciences, Leuven Brain Institute, Leuven, Belgium
| | - Luísa Santa-Marinha
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, Braga, Portugal
- ICVS/3B's - PT Government Associate Laboratory, Braga/Guimarães, Portugal
| | - Rafaela Morais-Ribeiro
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, Braga, Portugal
- ICVS/3B's - PT Government Associate Laboratory, Braga/Guimarães, Portugal
| | - Antonella Ruggiero
- Department of Physiology and Pharmacology, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Ivan Bozic
- Zentrum für Experimentelle Neurologie, Department of Neurology, Inselspital University Hospital Bern, University of Bern, Bern, Switzerland
| | - Thomas Rusterholz
- Zentrum für Experimentelle Neurologie, Department of Neurology, Inselspital University Hospital Bern, University of Bern, Bern, Switzerland
- Department of Biomedical Research, University of Bern, Bern, Switzerland
| | - Blanca Lorente-Echeverría
- VIB Center for Brain & Disease Research, Leuven, Belgium
- KU Leuven, Department of Neurosciences, Leuven Brain Institute, Leuven, Belgium
| | - Marcelo Dias
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, Braga, Portugal
- ICVS/3B's - PT Government Associate Laboratory, Braga/Guimarães, Portugal
| | - Wei-Ting Chen
- VIB Center for Brain & Disease Research, Leuven, Belgium
- KU Leuven, Department of Neurosciences, Leuven Brain Institute, Leuven, Belgium
| | - Mark Fiers
- VIB Center for Brain & Disease Research, Leuven, Belgium
- KU Leuven, Department of Neurosciences, Leuven Brain Institute, Leuven, Belgium
| | - Ashley Lu
- VIB Center for Brain & Disease Research, Leuven, Belgium
- KU Leuven, Department of Neurosciences, Leuven Brain Institute, Leuven, Belgium
| | - Ine Vlaeminck
- VIB Center for Brain & Disease Research, Leuven, Belgium
- KU Leuven, Department of Neurosciences, Leuven Brain Institute, Leuven, Belgium
| | - Eline Creemers
- VIB Center for Brain & Disease Research, Leuven, Belgium
- KU Leuven, Department of Neurosciences, Leuven Brain Institute, Leuven, Belgium
| | - Katleen Craessaerts
- VIB Center for Brain & Disease Research, Leuven, Belgium
- KU Leuven, Department of Neurosciences, Leuven Brain Institute, Leuven, Belgium
| | - Joris Vandenbempt
- VIB Center for Brain & Disease Research, Leuven, Belgium
- KU Leuven, Department of Neurosciences, Leuven Brain Institute, Leuven, Belgium
| | - Luuk van Boekholdt
- VIB Center for Brain & Disease Research, Leuven, Belgium
- KU Leuven, Department of Neurosciences, Leuven Brain Institute, Leuven, Belgium
- KU Leuven, Department of Otorhinolaryngology, Leuven, Belgium
| | - Suresh Poovathingal
- VIB Center for Brain & Disease Research, Leuven, Belgium
- KU Leuven, Department of Neurosciences, Leuven Brain Institute, Leuven, Belgium
| | - Kristofer Davie
- VIB Center for Brain & Disease Research, Leuven, Belgium
- KU Leuven, Department of Neurosciences, Leuven Brain Institute, Leuven, Belgium
| | - Dietmar Rudolf Thal
- Department of Imaging and Pathology, Laboratory of Neuropathology, and Leuven Brain Institute, KU-Leuven, O&N IV, Leuven, Belgium
- Department of Pathology, UZ Leuven, Leuven, Belgium
| | - Keimpe Wierda
- VIB Center for Brain & Disease Research, Leuven, Belgium
- KU Leuven, Department of Neurosciences, Leuven Brain Institute, Leuven, Belgium
| | - Tiago Gil Oliveira
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, Braga, Portugal
- ICVS/3B's - PT Government Associate Laboratory, Braga/Guimarães, Portugal
| | - Inna Slutsky
- Department of Physiology and Pharmacology, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
- Sagol School of Neuroscience, Tel Aviv University, Tel Aviv, Israel
| | - Antoine Adamantidis
- Zentrum für Experimentelle Neurologie, Department of Neurology, Inselspital University Hospital Bern, University of Bern, Bern, Switzerland
- Department of Biomedical Research, University of Bern, Bern, Switzerland
| | - Bart De Strooper
- VIB Center for Brain & Disease Research, Leuven, Belgium.
- KU Leuven, Department of Neurosciences, Leuven Brain Institute, Leuven, Belgium.
- UK Dementia Research Institute (UK DRI@UCL) at University College London, London, UK.
| | - Joris de Wit
- VIB Center for Brain & Disease Research, Leuven, Belgium.
- KU Leuven, Department of Neurosciences, Leuven Brain Institute, Leuven, Belgium.
| |
Collapse
|
5
|
Guo R, Vaughan DT, Rojo ALA, Huang YH. Sleep-mediated regulation of reward circuits: implications in substance use disorders. Neuropsychopharmacology 2023; 48:61-78. [PMID: 35710601 PMCID: PMC9700806 DOI: 10.1038/s41386-022-01356-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/07/2022] [Revised: 05/22/2022] [Accepted: 05/27/2022] [Indexed: 12/11/2022]
Abstract
Our modern society suffers from both pervasive sleep loss and substance abuse-what may be the indications for sleep on substance use disorders (SUDs), and could sleep contribute to the individual variations in SUDs? Decades of research in sleep as well as in motivated behaviors have laid the foundation for us to begin to answer these questions. This review is intended to critically summarize the circuit, cellular, and molecular mechanisms by which sleep influences reward function, and to reveal critical challenges for future studies. The review also suggests that improving sleep quality may serve as complementary therapeutics for treating SUDs, and that formulating sleep metrics may be useful for predicting individual susceptibility to SUDs and other reward-associated psychiatric diseases.
Collapse
Affiliation(s)
- Rong Guo
- Department of Psychiatry, University of Pittsburgh, Pittsburgh, PA, 15219, USA
- Allen Institute, Seattle, WA, 98109, USA
| | - Dylan Thomas Vaughan
- Department of Psychiatry, University of Pittsburgh, Pittsburgh, PA, 15219, USA
- The Center for Neuroscience at the University of Pittsburgh, Pittsburgh, PA, USA
| | - Ana Lourdes Almeida Rojo
- Department of Psychiatry, University of Pittsburgh, Pittsburgh, PA, 15219, USA
- The Center for Neuroscience at the University of Pittsburgh, Pittsburgh, PA, USA
| | - Yanhua H Huang
- Department of Psychiatry, University of Pittsburgh, Pittsburgh, PA, 15219, USA.
- The Center for Neuroscience at the University of Pittsburgh, Pittsburgh, PA, USA.
| |
Collapse
|
6
|
Guo R, Wang Y, Yan R, Chen B, Ding W, Gorczyca MT, Ozsoy S, Cai L, Hines RL, Tseng GC, Allocca G, Dong Y, Fang J, Huang YH. Rapid Eye Movement Sleep Engages Melanin-Concentrating Hormone Neurons to Reduce Cocaine Seeking. Biol Psychiatry 2022; 92:880-894. [PMID: 35953320 PMCID: PMC9872495 DOI: 10.1016/j.biopsych.2022.06.006] [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] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/23/2021] [Revised: 06/03/2022] [Accepted: 06/06/2022] [Indexed: 01/27/2023]
Abstract
BACKGROUND Persistent sleep disruptions following withdrawal from abused drugs may hold keys to battle drug relapse. It is posited that there may be sleep signatures that predict relapse propensity, identifying which may open new avenues for treating substance use disorders. METHODS We trained male rats (approximately postnatal day 56) to self-administer cocaine. After long-term drug withdrawal (approximately postnatal day 100), we examined the correlations between the intensity of cocaine seeking and key sleep features. To test for causal relationships, we then used behavioral, chemogenetic, or optogenetic methods to selectively increase rapid eye movement sleep (REMS) and measured behavioral and electrophysiological outcomes to probe for cellular and circuit mechanisms underlying REMS-mediated regulation of cocaine seeking. RESULTS A selective set of REMS features was preferentially associated with the intensity of cue-induced cocaine seeking after drug withdrawal. Moreover, selectively increasing REMS time and continuity by environmental warming attenuated a withdrawal time-dependent intensification of cocaine seeking, or incubation of cocaine craving, suggesting that REMS may benefit withdrawal. Warming increased the activity of lateral hypothalamic melanin-concentrating hormone (MCH) neurons selectively during prolonged REMS episodes and counteracted cocaine-induced synaptic accumulation of calcium-permeable AMPA receptors in the nucleus accumbens-a critical substrate for incubation. Finally, the warming effects were partly mimicked by chemogenetic or optogenetic stimulations of MCH neurons during sleep, or intra-accumbens infusions of MCH peptide during the rat's inactive phase. CONCLUSIONS REMS may encode individual vulnerability to relapse, and MCH neuron activities can be selectively targeted during REMS to reduce drug relapse.
Collapse
Affiliation(s)
- Rong Guo
- Department of Psychiatry, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Yao Wang
- Department of Psychiatry, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Rongzhen Yan
- Department of Psychiatry, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Bo Chen
- Department of Psychiatry, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Wanqiao Ding
- Department of Neuroscience, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Michael T Gorczyca
- Department of Biostatistics, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Sahin Ozsoy
- Somnivore Pty. Ltd., Bacchus Marsh, Victoria, Australia
| | - Li Cai
- Department of Psychiatry, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Rachel L Hines
- Department of Psychiatry, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - George C Tseng
- Department of Biostatistics, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Giancarlo Allocca
- Somnivore Pty. Ltd., Bacchus Marsh, Victoria, Australia; Department of Pharmacology and Therapeutics, University of Melbourne, Parkville, Victoria, Australia; Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, Victoria, Australia
| | - Yan Dong
- Department of Psychiatry, University of Pittsburgh, Pittsburgh, Pennsylvania; Department of Neuroscience, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Jidong Fang
- Department of Psychiatry and Behavioral Health, Penn State College of Medicine, Hershey, Pennsylvania
| | - Yanhua H Huang
- Department of Psychiatry, University of Pittsburgh, Pittsburgh, Pennsylvania.
| |
Collapse
|
7
|
Potter LE, Burgess CR. The melanin-concentrating hormone system as a target for the treatment of sleep disorders. Front Neurosci 2022; 16:952275. [PMID: 36177357 PMCID: PMC9513178 DOI: 10.3389/fnins.2022.952275] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2022] [Accepted: 08/24/2022] [Indexed: 11/13/2022] Open
Abstract
Given the widespread prevalence of sleep disorders and their impacts on health, it is critical that researchers continue to identify and evaluate novel avenues of treatment. Recently the melanin-concentrating hormone (MCH) system has attracted commercial and scientific interest as a potential target of pharmacotherapy for sleep disorders. This interest emerges from basic scientific research demonstrating a role for MCH in regulating sleep, and particularly REM sleep. In addition to this role in sleep regulation, the MCH system and the MCH receptor 1 (MCHR1) have been implicated in a wide variety of other physiological functions and behaviors, including feeding/metabolism, reward, anxiety, depression, and learning. The basic research literature on sleep and the MCH system, and the history of MCH drug development, provide cause for both skepticism and cautious optimism about the prospects of MCH-targeting drugs in sleep disorders. Extensive efforts have focused on developing MCHR1 antagonists for use in obesity, however, few of these drugs have advanced to clinical trials, and none have gained regulatory approval. Additional basic research will be needed to fully characterize the MCH system’s role in sleep regulation, for example, to fully differentiate between MCH-neuron and peptide/receptor-mediated functions. Additionally, a number of issues relating to drug design will continue to pose a practical challenge for novel pharmacotherapies targeting the MCH system.
Collapse
Affiliation(s)
- Liam E. Potter
- Department of Molecular and Integrative Physiology, Michigan Medicine, Ann Arbor, MI, United States
- Michigan Neuroscience Institute, University of Michigan, Ann Arbor, MI, United States
- *Correspondence: Liam E. Potter,
| | - Christian R. Burgess
- Department of Molecular and Integrative Physiology, Michigan Medicine, Ann Arbor, MI, United States
- Michigan Neuroscience Institute, University of Michigan, Ann Arbor, MI, United States
- Christian R. Burgess,
| |
Collapse
|
8
|
Liu J, Lai F, Hou Y, Zheng R. Leptin signaling and leptin resistance. MEDICAL REVIEW (BERLIN, GERMANY) 2022; 2:363-384. [PMID: 37724323 PMCID: PMC10388810 DOI: 10.1515/mr-2022-0017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/06/2022] [Accepted: 07/12/2022] [Indexed: 09/20/2023]
Abstract
With the prevalence of obesity and associated comorbidities, studies aimed at revealing mechanisms that regulate energy homeostasis have gained increasing interest. In 1994, the cloning of leptin was a milestone in metabolic research. As an adipocytokine, leptin governs food intake and energy homeostasis through leptin receptors (LepR) in the brain. The failure of increased leptin levels to suppress feeding and elevate energy expenditure is referred to as leptin resistance, which encompasses complex pathophysiological processes. Within the brain, LepR-expressing neurons are distributed in hypothalamus and other brain areas, and each population of the LepR-expressing neurons may mediate particular aspects of leptin effects. In LepR-expressing neurons, the binding of leptin to LepR initiates multiple signaling cascades including janus kinase (JAK)-signal transducers and activators of transcription (STAT) phosphatidylinositol 3-kinase (PI3K)-protein kinase B (AKT), extracellular regulated protein kinase (ERK), and AMP-activated protein kinase (AMPK) signaling, etc., mediating leptin actions. These findings place leptin at the intersection of metabolic and neuroendocrine regulations, and render leptin a key target for treating obesity and associated comorbidities. This review highlights the main discoveries that shaped the field of leptin for better understanding of the mechanism governing metabolic homeostasis, and guides the development of safe and effective interventions to treat obesity and associated diseases.
Collapse
Affiliation(s)
- Jiarui Liu
- Department of Anatomy, Histology and Embryology, School of Basic Medical Sciences, Health Science Center, Peking University, Beijing, China
| | - Futing Lai
- Department of Anatomy, Histology and Embryology, School of Basic Medical Sciences, Health Science Center, Peking University, Beijing, China
| | - Yujia Hou
- Department of Anatomy, Histology and Embryology, School of Basic Medical Sciences, Health Science Center, Peking University, Beijing, China
| | - Ruimao Zheng
- Department of Anatomy, Histology and Embryology, School of Basic Medical Sciences, Health Science Center, Peking University, Beijing, China
- Neuroscience Research Institute, Peking University, Beijing, China
- Key Laboratory for Neuroscience of Ministry of Education, Peking University, Beijing, China
- Key Laboratory for Neuroscience of National Health Commission, Peking University, Beijing 100191, China
| |
Collapse
|
9
|
Royo M, Escolano BA, Madrigal MP, Jurado S. AMPA Receptor Function in Hypothalamic Synapses. Front Synaptic Neurosci 2022; 14:833449. [PMID: 35173598 PMCID: PMC8842481 DOI: 10.3389/fnsyn.2022.833449] [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: 12/11/2021] [Accepted: 01/03/2022] [Indexed: 12/15/2022] Open
Abstract
AMPA receptors (AMPARs) are critical for mediating glutamatergic synaptic transmission and plasticity, thus playing a major role in the molecular machinery underlying cellular substrates of memory and learning. Their expression pattern, transport and regulatory mechanisms have been extensively studied in the hippocampus, but their functional properties in other brain regions remain poorly understood. Interestingly, electrophysiological and molecular evidence has confirmed a prominent role of AMPARs in the regulation of hypothalamic function. This review summarizes the existing evidence on AMPAR-mediated transmission in the hypothalamus, where they are believed to orchestrate the role of glutamatergic transmission in autonomous, neuroendocrine function, body homeostasis, and social behavior.
Collapse
|
10
|
Dopamine D2L Receptor Deficiency Alters Neuronal Excitability and Spine Formation in Mouse Striatum. Biomedicines 2022; 10:biomedicines10010101. [PMID: 35052781 PMCID: PMC8773425 DOI: 10.3390/biomedicines10010101] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2021] [Revised: 12/30/2021] [Accepted: 12/31/2021] [Indexed: 12/29/2022] Open
Abstract
The striatum contains several types of neurons including medium spiny projection neurons (MSNs), cholinergic interneurons (ChIs), and fast-spiking interneurons (FSIs). Modulating the activity of these neurons by the dopamine D2 receptor (D2R) can greatly impact motor control and movement disorders. D2R exists in two isoforms: D2L and D2S. Here, we assessed whether alterations in the D2L and D2S expression levels affect neuronal excitability and synaptic function in striatal neurons. We observed that quinpirole inhibited the firing rate of all three types of striatal neurons in wild-type (WT) mice. However, in D2L knockout (KO) mice, quinpirole enhanced the excitability of ChIs, lost influence on spike firing of MSNs, and remained inhibitory effect on spike firing of FSIs. Additionally, we showed mIPSC frequency (but not mIPSC amplitude) was reduced in ChIs from D2L KO mice compared with WT mice, suggesting spontaneous GABA release is reduced at GABAergic terminals onto ChIs in D2L KO mice. Furthermore, we found D2L deficiency resulted in reduced dendritic spine density in ChIs, suggesting D2L activation plays a role in the formation/maintenance of dendritic spines of ChIs. These findings suggest new molecular and cellular mechanisms for causing ChIs abnormality seen in Parkinson’s disease or drug-induced dyskinesias.
Collapse
|
11
|
The role of the nucleus accumbens and ventral pallidum in feeding and obesity. Prog Neuropsychopharmacol Biol Psychiatry 2021; 111:110394. [PMID: 34242717 DOI: 10.1016/j.pnpbp.2021.110394] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/22/2020] [Revised: 05/31/2021] [Accepted: 06/29/2021] [Indexed: 02/04/2023]
Abstract
Obesity is a growing global epidemic that stems from the increasing availability of highly-palatable foods and the consequent enhanced calorie consumption. Extensive research has shown that brain regions that are central to reward seeking modulate feeding and evidence linking obesity to pathology in such regions have recently started to accumulate. In this review we focus on the contribution of two major interconnected structures central to reward processing, the nucleus accumbens and the ventral pallidum, to obesity. We first review the known literature linking these structures to feeding behavior, then discuss recent advances connecting pathology in the nucleus accumbens and ventral pallidum to obesity, and finally examine the similarities and differences between drug addiction and obesity in the context of these two structures. The understanding of how pathology in brain regions involved in reward seeking and consumption may drive obesity and how mechanistically similar obesity and addiction are, is only now starting to be revealed. We hope that future research will advance knowledge in the field and open new avenues to studying and treating obesity.
Collapse
|
12
|
Lee J, Raycraft L, Johnson AW. The dynamic regulation of appetitive behavior through lateral hypothalamic orexin and melanin concentrating hormone expressing cells. Physiol Behav 2020; 229:113234. [PMID: 33130035 DOI: 10.1016/j.physbeh.2020.113234] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2020] [Revised: 10/20/2020] [Accepted: 10/21/2020] [Indexed: 02/07/2023]
Abstract
The lateral hypothalamic area (LHA) is a heterogeneous brain structure extensively studied for its potent role in regulating energy balance. The anatomical and molecular diversity of the LHA permits the orchestration of responses to energy sensing cues from the brain and periphery. Two of the primary cell populations within the LHA associated with integration of this information are Orexin (ORX) and Melanin Concentrating Hormone (MCH). While both of these non-overlapping populations exhibit orexigenic properties, the activities of these two systems support feeding behavior through contrasting mechanisms. We describe the anatomical and functional properties as well as interaction with other neuropeptides and brain reward and hedonic systems. Specific outputs relating to arousal, food seeking, feeding, and metabolism are coordinated through these mechanisms. We then discuss how both the ORX and MCH systems harmonize in a divergent yet overall cooperative manner to orchestrate feeding behavior through transitions between various appetitive states, and thus offer novel insights into LHA allostatic control of appetite.
Collapse
Affiliation(s)
| | | | - Alexander W Johnson
- Department of Psychology; Neuroscience Program, Michigan State University, East Lansing.
| |
Collapse
|
13
|
Liu X, Gao S, Zhang N, Jin T, Sun X, Luan X, Xu L, Guo F. The orexinergic neural pathway from the lateral hypothalamus to the nucleus accumbens and its regulation of palatable food intake. Neuropeptides 2020; 80:102028. [PMID: 32067750 DOI: 10.1016/j.npep.2020.102028] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/09/2019] [Revised: 01/09/2020] [Accepted: 02/05/2020] [Indexed: 12/31/2022]
Abstract
OBJECTIVE To explore the orexinergic pathway from the lateral hypothalamus (LHA) to the nucleus accumbens (NAc) and its regulation on the palatable food intake. METHODS Fluorescent gold retrograde tracing combined with fluoro-immunohistochemical staining were used to observe the projection of orexinergic neurons from LHA to NAc. The orexin-A expression in LHA and c-Fos in NAc were studied after electrical stimulation of LHA. The firing rates of neurons were monitored by single-unit extracellular electric discharge recording and the palatable food intake were measured after orexin microinjection in NAc or electrical stimulation of LHA. RESULTS (1) Fluorescent gold retrograde tracing combined with fluoro-immunohistochemical staining showed some orexinergic neural projection from the LHA to the NAc shell. (2) Electrical stimulation of LHA significantly enhanced the expression of orexin-A in LHA and the expression of c-Fos in NAc (P < .05). (3) The results of single-unit extracellular discharge recording showed that the microinjection of orexin in NAc or electrical stimulation of LHA significantly increased the discharge activity of gastric distension responsive neurons in NAc, and the effect could be partly blocked by pretreatment of orexin-A receptor inhibitor SB334867 in NAc (P < .05). (4) Microinjection orexin-A in NAc or electrical stimulation of LHA significantly increased the palatable food intake in rats, and the effect also was partly inhibited by pretreatment of SB334867 in NAc (P < .05). CONCLUSION There is an orexinergic pathway from LHA to NAc, which may have potential regulatory effects on food reward and obesity.
Collapse
Affiliation(s)
- Xiaoning Liu
- Pathophysiology Department, School of Basic Medicine, Qingdao University, Qingdao, Shandong, China
| | - Shengli Gao
- Pathophysiology Department, School of Basic Medicine, Qingdao University, Qingdao, Shandong, China
| | - Nana Zhang
- Department of Clinical Laboratory, The Affiliated Hospital of Qingdao University, Qingdao, Shandong, China
| | - Tingting Jin
- Pathophysiology Department, School of Basic Medicine, Qingdao University, Qingdao, Shandong, China
| | - Xiangrong Sun
- Pathophysiology Department, School of Basic Medicine, Qingdao University, Qingdao, Shandong, China
| | - Xiao Luan
- Pathophysiology Department, School of Basic Medicine, Qingdao University, Qingdao, Shandong, China
| | - Luo Xu
- Pathophysiology Department, School of Basic Medicine, Qingdao University, Qingdao, Shandong, China
| | - Feifei Guo
- Pathophysiology Department, School of Basic Medicine, Qingdao University, Qingdao, Shandong, China.
| |
Collapse
|
14
|
Wang D, Zhang J, Bai Y, Zheng X, Alizamini MM, Shang W, Yang Q, Li M, Li Y, Sui N. Melanin-concentrating hormone in rat nucleus accumbens or lateral hypothalamus differentially impacts morphine and food seeking behaviors. J Psychopharmacol 2020; 34:478-489. [PMID: 31909693 DOI: 10.1177/0269881119895521] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
BACKGROUND Identifying neural substrates that are differentially affected by drugs of abuse and natural rewards is key to finding a target for an efficacious treatment for substance abuse. Melanin-concentrating hormone is a polypeptide with an inhibitory effect on the mesolimbic dopamine system. Here we test the hypothesis that melanin-concentrating hormone in the lateral hypothalamus and nucleus accumbens shell is differentially involved in the regulation of morphine and food-rewarded behaviors. METHODS Male Sprague-Dawley rats were trained with morphine (5.0 mg/kg, subcutaneously) or food pellets (standard chow, 10-14 g) to induce a conditioned place preference, immediately followed by extinction training. Melanin-concentrating hormone (1.0 µg/side) or saline was infused into the nucleus accumbens shell or lateral hypothalamus before the reinstatement primed by morphine or food, and locomotor activity was simultaneously monitored. As the comparison, melanin-concentrating hormone was also microinjected into the nucleus accumbens shell or lateral hypothalamus before the expression of food or morphine-induced conditioned place preference. RESULTS Microinfusion of melanin-concentrating hormone into the nucleus accumbens shell (but not into the lateral hypothalamus) prevented the reinstatement of morphine conditioned place preference but had no effect on the reinstatement of food conditioned place preference. In contrast, microinfusion of melanin-concentrating hormone into the lateral hypothalamus (but not in the nucleus accumbens shell) inhibited the reinstatement of food conditioned place preference but had no effect on the reinstatement of morphine conditioned place preference. CONCLUSIONS These results suggest a clear double dissociation of melanin-concentrating hormone in morphine/food rewarding behaviors and melanin-concentrating hormone in the nucleus accumbens shell. Melanin-concentrating hormone could be a potential target for therapeutic intervention for morphine abuse without affecting natural rewards.
Collapse
Affiliation(s)
- Dongmei Wang
- CAS Key Laboratory of Mental Health, Institute of Psychology, Beijing, China.,Department of Psychology, University of Chinese Academy of Sciences, Beijing, China
| | - Jianjun Zhang
- CAS Key Laboratory of Mental Health, Institute of Psychology, Beijing, China.,Department of Psychology, University of Chinese Academy of Sciences, Beijing, China
| | - Yunjing Bai
- CAS Key Laboratory of Mental Health, Institute of Psychology, Beijing, China.,Department of Psychology, University of Chinese Academy of Sciences, Beijing, China
| | - Xigeng Zheng
- CAS Key Laboratory of Mental Health, Institute of Psychology, Beijing, China.,Department of Psychology, University of Chinese Academy of Sciences, Beijing, China
| | - Mirmohammadali M Alizamini
- CAS Key Laboratory of Mental Health, Institute of Psychology, Beijing, China.,Department of Psychology, University of Chinese Academy of Sciences, Beijing, China
| | - Wen Shang
- CAS Key Laboratory of Mental Health, Institute of Psychology, Beijing, China.,Department of Psychology, University of Chinese Academy of Sciences, Beijing, China
| | - Qingxiong Yang
- School of Karst Science, Guizhou Normal University/State Engineering Technology Institute for Karst Desertification Control, Guiyang, China
| | - Ming Li
- Department of Psychology, University of Nebraska-Lincoln, Lincoln, NE, USA
| | - Yonghui Li
- CAS Key Laboratory of Mental Health, Institute of Psychology, Beijing, China.,Department of Psychology, University of Chinese Academy of Sciences, Beijing, China
| | - Nan Sui
- CAS Key Laboratory of Mental Health, Institute of Psychology, Beijing, China.,Department of Psychology, University of Chinese Academy of Sciences, Beijing, China
| |
Collapse
|
15
|
Negishi K, Payant MA, Schumacker KS, Wittmann G, Butler RM, Lechan RM, Steinbusch HWM, Khan AM, Chee MJ. Distributions of hypothalamic neuron populations coexpressing tyrosine hydroxylase and the vesicular GABA transporter in the mouse. J Comp Neurol 2020; 528:1833-1855. [PMID: 31950494 DOI: 10.1002/cne.24857] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2019] [Revised: 12/20/2019] [Accepted: 01/03/2020] [Indexed: 12/21/2022]
Abstract
The hypothalamus contains catecholaminergic neurons marked by the expression of tyrosine hydroxylase (TH). As multiple chemical messengers coexist in each neuron, we determined if hypothalamic TH-immunoreactive (ir) neurons express vesicular glutamate or GABA transporters. We used Cre/loxP recombination to express enhanced GFP (EGFP) in neurons expressing the vesicular glutamate (vGLUT2) or GABA transporter (vGAT), then determined whether TH-ir neurons colocalized with native EGFPVglut2 - or EGFPVgat -fluorescence, respectively. EGFPVglut2 neurons were not TH-ir. However, discrete TH-ir signals colocalized with EGFPVgat neurons, which we validated by in situ hybridization for Vgat mRNA. To contextualize the observed pattern of colocalization between TH-ir and EGFPVgat , we first performed Nissl-based parcellation and plane-of-section analysis, and then mapped the distribution of TH-ir EGFPVgat neurons onto atlas templates from the Allen Reference Atlas (ARA) for the mouse brain. TH-ir EGFPVgat neurons were distributed throughout the rostrocaudal extent of the hypothalamus. Within the ARA ontology of gray matter regions, TH-ir neurons localized primarily to the periventricular hypothalamic zone, periventricular hypothalamic region, and lateral hypothalamic zone. There was a strong presence of EGFPVgat fluorescence in TH-ir neurons across all brain regions, but the most striking colocalization was found in a circumscribed portion of the zona incerta (ZI)-a region assigned to the hypothalamus in the ARA-where every TH-ir neuron expressed EGFPVgat . Neurochemical characterization of these ZI neurons revealed that they display immunoreactivity for dopamine but not dopamine β-hydroxylase. Collectively, these findings indicate the existence of a novel mouse hypothalamic population that may signal through the release of GABA and/or dopamine.
Collapse
Affiliation(s)
- Kenichiro Negishi
- UTEP Systems Neuroscience Laboratory, Department of Biological Sciences, and Border Biomedical Research Center, University of Texas at El Paso, El Paso, Texas
| | - Mikayla A Payant
- Department of Neuroscience, Carleton University, Ottawa, Ontario, Canada
| | - Kayla S Schumacker
- Department of Neuroscience, Carleton University, Ottawa, Ontario, Canada
| | - Gabor Wittmann
- Department of Medicine, Division of Endocrinology, Diabetes and Metabolism, Tufts Medical Center, Boston, Massachusetts
| | - Rebecca M Butler
- Department of Neuroscience, Carleton University, Ottawa, Ontario, Canada
| | - Ronald M Lechan
- Department of Medicine, Division of Endocrinology, Diabetes and Metabolism, Tufts Medical Center, Boston, Massachusetts
| | - Harry W M Steinbusch
- Department of Psychiatry and Neuropsychology, Section Cellular Neuroscience, Maastricht University, Maastricht, Netherlands
| | - Arshad M Khan
- UTEP Systems Neuroscience Laboratory, Department of Biological Sciences, and Border Biomedical Research Center, University of Texas at El Paso, El Paso, Texas
| | - Melissa J Chee
- Department of Neuroscience, Carleton University, Ottawa, Ontario, Canada
| |
Collapse
|
16
|
Coccurello R. Anhedonia in depression symptomatology: Appetite dysregulation and defective brain reward processing. Behav Brain Res 2019; 372:112041. [DOI: 10.1016/j.bbr.2019.112041] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2019] [Revised: 06/13/2019] [Accepted: 06/14/2019] [Indexed: 12/22/2022]
|
17
|
Vawter MP, Schulmann A, Alhassen L, Alhassen W, Hamzeh AR, Sakr J, Pauluk L, Yoshimura R, Wang X, Dai Q, Sanathara N, Civelli O, Alachkar A. Melanin Concentrating Hormone Signaling Deficits in Schizophrenia: Association With Memory and Social Impairments and Abnormal Sensorimotor Gating. Int J Neuropsychopharmacol 2019; 23:53-65. [PMID: 31563948 PMCID: PMC7442395 DOI: 10.1093/ijnp/pyz051] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/09/2019] [Revised: 08/30/2019] [Accepted: 09/24/2019] [Indexed: 11/12/2022] Open
Abstract
BACKGROUND Evidence from anatomical, pharmacological, and genetic studies supports a role for the neuropeptide melanin concentrating hormone system in modulating emotional and cognitive functions. Genome-wide association studies revealed a potential association between the melanin concentrating hormone receptor (MCHR1) gene locus and schizophrenia, and the largest genome-wide association study conducted to date shows a credible genome-wide association. METHODS We analyzed MCHR1 and pro-melanin concentrating hormone RNA-Seq expression in the prefrontal cortex in schizophrenia patients and healthy controls. Disruptions in the melanin concentrating hormone system were modeled in the mouse brain by germline deletion of MCHR1 and by conditional ablation of melanin concentrating hormone expressing neurons using a Cre-inducible diphtheria toxin system. RESULTS MCHR1 expression is decreased in the prefrontal cortex of schizophrenia samples (false discovery rate (FDR) P < .05, CommonMind and PsychEncode combined datasets, n = 901) while pro-melanin concentrating hormone is below the detection threshold. MCHR1 expression decreased with aging (P = 6.6E-57) in human dorsolateral prefrontal cortex. The deletion of MCHR1 was found to lead to behavioral abnormalities mimicking schizophrenia-like phenotypes: hyperactivity, increased stereotypic and repetitive behavior, social impairment, impaired sensorimotor gating, and disrupted cognitive functions. Conditional ablation of pro-melanin concentrating hormone neurons increased repetitive behavior and produced a deficit in sensorimotor gating. CONCLUSIONS Our study indicates that early disruption of the melanin concentrating hormone system interferes with neurodevelopmental processes, which may contribute to the pathogenesis of schizophrenia. Further neurobiological research on the developmental timing and circuits that are affected by melanin concentrating hormone may lead to a therapeutic target for early prevention of schizophrenia.
Collapse
Affiliation(s)
- Marquis P Vawter
- Department of Psychiatry and Human Behavior, School of Medicine, University of California, Irvine, CA,Correspondence: Marquis P. Vawter, PhD, Department of Psychiatry and Human Behavior, School of Medicine, University of California, Irvine, CA 92617 (); and Dr Amal Alachkar, Department of Pharmaceutical Sciences, University of California, Irvine, CA ()
| | - Anton Schulmann
- Department of Psychiatry and Human Behavior, School of Medicine, University of California, Irvine, CA,Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA
| | - Lamees Alhassen
- Department of Psychiatry and Human Behavior, School of Medicine, University of California, Irvine, CA
| | - Wedad Alhassen
- Department of Pharmacology, School of Medicine, University of California, Irvine, CA,Department of Pharmaceutical Sciences, University of California, Irvine, CA
| | - Abdul Rezzak Hamzeh
- John Curtin School of Medical Research, Australian National University, Canberra
| | - Jasmine Sakr
- Department of Pharmaceutical Sciences, University of California, Irvine, CA
| | - Lucas Pauluk
- Department of Pharmacology, School of Medicine, University of California, Irvine, CA
| | - Ryan Yoshimura
- Department of Pharmacology, School of Medicine, University of California, Irvine, CA
| | - Xuejie Wang
- Department of Pharmacology, School of Medicine, University of California, Irvine, CA
| | - Qi Dai
- Department of Pharmacology, School of Medicine, University of California, Irvine, CA
| | - Nayna Sanathara
- Department of Pharmacology, School of Medicine, University of California, Irvine, CA
| | - Olivier Civelli
- Department of Pharmacology, School of Medicine, University of California, Irvine, CA,Department of Pharmaceutical Sciences, University of California, Irvine, CA,Department of Developmental and Cell Biology, School of Medicine, University of California, Irvine, CA
| | - Amal Alachkar
- Department of Pharmaceutical Sciences, University of California, Irvine, CA,Correspondence: Marquis P. Vawter, PhD, Department of Psychiatry and Human Behavior, School of Medicine, University of California, Irvine, CA 92617 (); and Dr Amal Alachkar, Department of Pharmaceutical Sciences, University of California, Irvine, CA ()
| |
Collapse
|
18
|
Chee MJ, Hebert AJ, Briançon N, Flaherty SE, Pissios P, Maratos-Flier E. Conditional deletion of melanin-concentrating hormone receptor 1 from GABAergic neurons increases locomotor activity. Mol Metab 2019; 29:114-123. [PMID: 31668382 PMCID: PMC6745487 DOI: 10.1016/j.molmet.2019.08.018] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/15/2019] [Revised: 08/23/2019] [Accepted: 08/25/2019] [Indexed: 12/28/2022] Open
Abstract
Objective Melanin-concentrating hormone (MCH) plays a key role in regulating energy balance. MCH acts via its receptor MCHR1, and MCHR1 deletion increases energy expenditure and locomotor activity, which is associated with a hyperdopaminergic state. Since MCHR1 expression is widespread, the neurons supporting the effects of MCH on energy expenditure are not clearly defined. There is a high density of MCHR1 neurons in the striatum, and these neurons are known to be GABAergic. We thus determined if MCH acts via this GABAergic neurocircuit to mediate energy balance. Methods We generated a Mchr1-flox mouse and crossed it with the Vgat-cre mouse to assess if MCHR1 deletion from GABAergic neurons expressing the vesicular GABA transporter (vGAT) in female Vgat-Mchr1-KO mice resulted in lower body weights or increased energy expenditure. Additionally, we determined if MCHR1-expressing neurons within the accumbens form part of the neural circuit underlying MCH-mediated energy balance by delivering an adeno-associated virus expressing Cre recombinase to the accumbens nucleus of Mchr1-flox mice. To evaluate if a dysregulated dopaminergic tone leads to their hyperactivity, we determined if the dopamine reuptake blocker GBR12909 prolonged the drug-induced locomotor activity in Vgat-Mchr1-KO mice. Furthermore, we also performed amperometry recordings to test whether MCHR1 deletion increases dopamine output within the accumbens and whether MCH can suppress dopamine release. Results Vgat-Mchr1-KO mice have lower body weight, increased energy expenditure, and increased locomotor activity. Similarly, restricting MCHR1 deletion to the accumbens nucleus also increased locomotor activity. Vgat-Mchr1-KO mice show increased and prolonged sensitivity to GBR12909-induced locomotor activity, and amperometry recordings revealed that GBR12909 elevated accumbens dopamine levels to twice that of controls, thus MCHR1 deletion may lead to a hyperdopaminergic state that mediates their observed hyperactivity. Consistent with the inhibitory effect of MCH, we found that MCH acutely suppresses dopamine release within the accumbens. Conclusions As with established models of systemic MCH or MCHR1 deletion, we found that MCHR1 deletion from GABAergic neurons, specifically those within the accumbens nucleus, also led to increased locomotor activity. A hyperdopaminergic state underlies this increased locomotor activity, and is consistent with our finding that MCH signaling within the accumbens nucleus suppresses dopamine release. In effect, MCHR1 deletion may disinhibit dopamine release leading to the observed hyperactivity. Generation of Mchr1-flox mouse enabled cre-mediated deletion of Mchr1. Mchr1 deletion at GABAergic neurons decreased body weight. Mchr1 deletion at GABAergic neurons increased locomotor activity. Mchr1 deletion increased dopaminergic tone in the mesolimbic accumbens circuitry. MCH suppressed dopamine release in the accumbens nucleus.
Collapse
Affiliation(s)
- Melissa J Chee
- Department of Neuroscience, Carleton University, Ottawa, ON, Canada; Division of Endocrinology, Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA.
| | - Alex J Hebert
- Department of Neuroscience, Carleton University, Ottawa, ON, Canada; Division of Endocrinology, Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA
| | - Nadege Briançon
- Division of Endocrinology, Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA
| | - Stephen E Flaherty
- Division of Endocrinology, Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA
| | - Pavlos Pissios
- Division of Endocrinology, Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA
| | - Eleftheria Maratos-Flier
- Division of Endocrinology, Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA
| |
Collapse
|
19
|
Neuronal cAMP/PKA Signaling and Energy Homeostasis. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2019; 1090:31-48. [PMID: 30390284 DOI: 10.1007/978-981-13-1286-1_3] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The brain plays a key role in the regulation of body weight and glucose metabolism. Peripheral signals including hormones, metabolites, and neural afferent signals are received and processed by the brain which in turn elicits proper behavioral and metabolic responses for maintaining energy and glucose homeostasis. The cAMP/protein kinase A (PKA) pathway acts downstream G-protein-coupled receptors (GPCR) to mediate the physiological effects of many hormones and neurotransmitters. Activated PKA phosphorylates various proteins including ion channels, enzymes, and transcription factors and regulates their activity. Recent studies have shown that neuronal cAMP/PKA activity in multiple brain regions are involved in the regulation of feeding, energy expenditure, and glucose homeostasis. In this chapter I summarize recent genetic and pharmacological studies concerning the regulation of body weight and glucose homeostasis by cAMP/PKA signaling in the brain.
Collapse
|
20
|
Arrigoni E, Chee MJS, Fuller PM. To eat or to sleep: That is a lateral hypothalamic question. Neuropharmacology 2018; 154:34-49. [PMID: 30503993 DOI: 10.1016/j.neuropharm.2018.11.017] [Citation(s) in RCA: 77] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2018] [Revised: 11/08/2018] [Accepted: 11/12/2018] [Indexed: 12/15/2022]
Abstract
The lateral hypothalamus (LH) is a functionally and anatomically complex brain region that is involved in the regulation of many behavioral and physiological processes including feeding, arousal, energy balance, stress, reward and motivated behaviors, pain perception, body temperature regulation, digestive functions and blood pressure. Despite noteworthy experimental efforts over the past decades, the circuit, cellular and synaptic bases by which these different processes are regulated by the LH remains incompletely understood. This knowledge gap links in large part to the high cellular heterogeneity of the LH. Fortunately, the rapid evolution of newer genetic and electrophysiological tools is now permitting the selective manipulation, typically genetically-driven, of discrete LH cell populations. This, in turn, permits not only assignment of function to discrete cell groups, but also reveals that considerable synergistic and antagonistic interactions exist between key LH cell populations that regulate feeding and arousal. For example, we now know that while LH melanin-concentrating hormone (MCH) and orexin/hypocretin neurons both function as sensors of the internal metabolic environment, their roles regulating sleep and arousal are actually opposing. Additional studies have uncovered similarly important roles for subpopulations of LH GABAergic cells in the regulation of both feeding and arousal. Herein we review the role of LH MCH, orexin/hypocretin and GABAergic cell populations in the regulation of energy homeostasis (including feeding) and sleep-wake and discuss how these three cell populations, and their subpopulations, may interact to optimize and coordinate metabolism, sleep and arousal. This article is part of the Special Issue entitled 'Hypothalamic Control of Homeostasis'.
Collapse
Affiliation(s)
- Elda Arrigoni
- Department of Neurology, Beth Israel Deaconess Medical Center, Division of Sleep Medicine, Harvard Medical School, Boston, MA, 02215, USA.
| | - Melissa J S Chee
- Department of Neuroscience, Carleton University, Ottawa, ON, K1S 5B6, Canada
| | - Patrick M Fuller
- Department of Neurology, Beth Israel Deaconess Medical Center, Division of Sleep Medicine, Harvard Medical School, Boston, MA, 02215, USA
| |
Collapse
|
21
|
Chakravarthy S, Balasubramani PP, Mandali A, Jahanshahi M, Moustafa AA. The many facets of dopamine: Toward an integrative theory of the role of dopamine in managing the body's energy resources. Physiol Behav 2018; 195:128-141. [DOI: 10.1016/j.physbeh.2018.06.032] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2018] [Revised: 05/07/2018] [Accepted: 06/20/2018] [Indexed: 02/07/2023]
|
22
|
Leigh SJ, Morris MJ. The role of reward circuitry and food addiction in the obesity epidemic: An update. Biol Psychol 2018; 131:31-42. [DOI: 10.1016/j.biopsycho.2016.12.013] [Citation(s) in RCA: 72] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2016] [Revised: 10/10/2016] [Accepted: 12/15/2016] [Indexed: 12/22/2022]
|
23
|
Melanin-Concentrating Hormone acts through hypothalamic kappa opioid system and p70S6K to stimulate acute food intake. Neuropharmacology 2017; 130:62-70. [PMID: 29191753 DOI: 10.1016/j.neuropharm.2017.11.040] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2017] [Revised: 10/28/2017] [Accepted: 11/24/2017] [Indexed: 12/12/2022]
Abstract
Melanin-Concentrating Hormone (MCH) is one of the most relevant orexigenic factors specifically located in the lateral hypothalamic area (LHA), with its physiological relevance demonstrated in studies using several genetically manipulated mice models. However, the central mechanisms controlling MCH-induced hyperphagia remain largely uncharacterized. Here, we show that central injection of MCH in mice deficient for kappa opoid receptor (k-OR) failed to stimulate feeding. To determine the hypothalamic area responsible for this MCH/k-OR interaction, we performed virogenetic studies and found that downregulation of k-OR by adeno-associated viruses (shOprk1-AAV) in LHA, but not in other hypothalamic nuclei, was sufficient to block MCH-induced food intake. Next, we sought to investigate the molecular signaling pathway within the LHA that mediates acute central MCH stimulation of food intake. We found that MCH activates k-OR and that increased levels of phosphorylated extracellular signal regulated kinase (ERK) are associated with downregulation of phospho-S6 Ribosomal Protein. This effect was prevented when a pharmacological inhibitor of k-OR was co-administered with MCH. Finally, the specific activation of the direct upstream regulator of S6 (p70S6K) in the LHA attenuated MCH-stimulated food consumption. Our results reveal that lateral hypothalamic k-OR system modulates the orexigenic action of MCH via the p70S6K/S6 pathway.
Collapse
|
24
|
Lazzari P, Serra V, Marcello S, Pira M, Mastinu A. Metabolic side effects induced by olanzapine treatment are neutralized by CB1 receptor antagonist compounds co-administration in female rats. Eur Neuropsychopharmacol 2017; 27:667-678. [PMID: 28377074 DOI: 10.1016/j.euroneuro.2017.03.010] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/07/2016] [Revised: 03/05/2017] [Accepted: 03/23/2017] [Indexed: 12/24/2022]
Abstract
Weight gain is an important side effect of most atypical antipsychotic drugs such as olanzapine. Moreover, although many animal models with metabolic side effects have been well defined, the interaction with other pathways has to be considered. The endocannabinoid system and the CB1 receptor (CB1R) are among the most promising central and peripheral targets involved in weight and energy balance. In this study we developed a rat model based 15-days treatment with olanzapine that shows weight gain and an alteration of the blood parameters involved in the regulation of energy balance and glucose metabolism. Consequently, we analysed whether, and by which mechanism, a co-treatment with the novel CB1R neutral antagonist NESS06SM, could attenuate the adverse metabolic effects of olanzapine compared to the reference CB1R inverse agonist rimonabant. Our results showed alterations of the cannabinoid markers in the nucleus accumbens and of orexigenic/anorexigenic markers in the hypothalamus of female rats treated with olanzapine. These molecular modifications could explain the excessive food intake and the resulting weight gain. Moreover, we confirmed that a co-treatment with CB1R antagonist/inverse agonist compounds decreased food intake and weight increment and restored all blood parameters, without altering the positive effects of olanzapine on behaviour. Furthermore, rimonabant and NESS06SM restored the metabolic enzymes in the liver and fat tissue altered by olanzapine. Therefore, CB1 receptor antagonist/inverse agonist compounds could be good candidate agents for the treatment of weight gain induced by olanzapine.
Collapse
Affiliation(s)
- P Lazzari
- Kemotech Srl, Edificio 3, Località Piscinamanna, 09010 Pula, CA, Italy
| | - V Serra
- Institute of Translational Pharmacology, UOS of Cagliari, National Research Council, Scientific and Technological Park of Sardinia - Polaris, Pula, CA, Italy
| | - S Marcello
- Institute of Translational Pharmacology, UOS of Cagliari, National Research Council, Scientific and Technological Park of Sardinia - Polaris, Pula, CA, Italy
| | - M Pira
- Kemotech Srl, Edificio 3, Località Piscinamanna, 09010 Pula, CA, Italy
| | - A Mastinu
- Department of Molecular and Translational Medicine, University of Brescia, 25123 Brescia, Italy; Institute of Translational Pharmacology, UOS of Cagliari, National Research Council, Scientific and Technological Park of Sardinia - Polaris, Pula, CA, Italy.
| |
Collapse
|
25
|
Abstract
Obesity is a global epidemic that contributes to a number of health complications including cardiovascular disease, type 2 diabetes, cancer and neuropsychiatric disorders. Pharmacotherapeutic strategies to treat obesity are urgently needed. Research over the past two decades has increased substantially our knowledge of central and peripheral mechanisms underlying homeostatic energy balance. Homeostatic mechanisms involve multiple components including neuronal circuits, some originating in hypothalamus and brain stem, as well as peripherally-derived satiety, hunger and adiposity signals that modulate neural activity and regulate eating behavior. Dysregulation of one or more of these homeostatic components results in obesity. Coincident with obesity, reward mechanisms that regulate hedonic aspects of food intake override the homeostatic regulation of eating. In addition to functional interactions between homeostatic and reward systems in the regulation of food intake, homeostatic signals have the ability to alter vulnerability to drug abuse. Regarding the treatment of obesity, pharmacological monotherapies primarily focus on a single protein target. FDA-approved monotherapy options include phentermine (Adipex-P®), orlistat (Xenical®), lorcaserin (Belviq®) and liraglutide (Saxenda®). However, monotherapies have limited efficacy, in part due to the recruitment of alternate and counter-regulatory pathways. Consequently, a multi-target approach may provide greater benefit. Recently, two combination products have been approved by the FDA to treat obesity, including phentermine/topiramate (Qsymia®) and naltrexone/bupropion (Contrave®). The current review provides an overview of homeostatic and reward mechanisms that regulate energy balance, potential therapeutic targets for obesity and current treatment options, including some candidate therapeutics in clinical development. Finally, challenges in anti-obesity drug development are discussed.
Collapse
Affiliation(s)
- Vidya Narayanaswami
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, Lexington, KY, 40536, USA
| | - Linda P Dwoskin
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, Lexington, KY, 40536, USA.
| |
Collapse
|
26
|
Somalwar AR, Shelkar GP, Subhedar NK, Kokare DM. The role of neuropeptide CART in the lateral hypothalamic-ventral tegmental area (LH-VTA) circuit in motivation. Behav Brain Res 2017; 317:340-349. [DOI: 10.1016/j.bbr.2016.09.054] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2016] [Revised: 09/20/2016] [Accepted: 09/24/2016] [Indexed: 12/20/2022]
|
27
|
Abstract
Many of the neurocircuits and hormones known to underlie the sensations of hunger and satiety also substantially alter the activity of the dopaminergic reward system. Much interest lies in the ways that hunger, satiety, and reward tie together, as the epidemic of obesity seems tied to the recent development and mass availability of highly palatable foods. In this review, we will first discuss the basic neurocircuitry of the midbrain and basal forebrain reward system. We will elaborate how several important mediators of hunger-the agouti-related protein neurons of the arcuate nucleus, the lateral hypothalamic nucleus, and ghrelin-enhance the sensitivity of the dopaminergic reward system. Then, we will elaborate how mediators of satiety-the nucleus tractus solitarius, pro-opiomelanocortin neurons of the arcuate nucleus, and its peripheral hormonal influences such as leptin-reduce the reward system sensitivity. We hope to provide a template by which future research may identify the ways in which highly rewarding foods bypass this balanced system to produce excessive food consumption.
Collapse
Affiliation(s)
- Ryan Michael Cassidy
- Brown Foundation of the Institute of Molecular Medicine for the Prevention of Human Diseases of McGovern Medical School, Neuroscience Program MD Anderson Cancer Center and UTHealth Graduate School of Biological Sciences, The University of Texas Health Science Center at Houston, Houston, TX, USA
- *Correspondence: Ryan Michael Cassidy,
| | - Qingchun Tong
- Brown Foundation of the Institute of Molecular Medicine for the Prevention of Human Diseases of McGovern Medical School, Neuroscience Program MD Anderson Cancer Center and UTHealth Graduate School of Biological Sciences, The University of Texas Health Science Center at Houston, Houston, TX, USA
| |
Collapse
|
28
|
Devarakonda K, Mobbs CV. Mechanisms and significance of brain glucose signaling in energy balance, glucose homeostasis, and food-induced reward. Mol Cell Endocrinol 2016; 438:61-69. [PMID: 27637346 DOI: 10.1016/j.mce.2016.09.012] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/10/2016] [Revised: 09/12/2016] [Accepted: 09/12/2016] [Indexed: 12/15/2022]
Abstract
The concept that hypothalamic glucose signaling plays an important role in regulating energy balance, e.g., as instantiated in the so-called "glucostat" hypothesis, is one of the oldest in the field of metabolism. However the mechanisms by which neurons in the hypothalamus sense glucose, and the function of glucose signaling in the brain, has been difficult to establish. Nevertheless recent studies probing mechanisms of glucose signaling have also strongly supported a role for glucose signaling in regulating energy balance, glucose homeostasis, and food-induced reward.
Collapse
Affiliation(s)
- Kavya Devarakonda
- Department of Neuroscience, Icahn School of Medicine at Mount Sinai, 1470 Madison Ave., 9-119, New York, NY 10029, USA; Department of Endocrinology, Icahn School of Medicine at Mount Sinai, 1470 Madison Ave., 9-119, New York, NY 10029, USA
| | - Charles V Mobbs
- Department of Neuroscience, Icahn School of Medicine at Mount Sinai, 1470 Madison Ave., 9-119, New York, NY 10029, USA; Department of Endocrinology, Icahn School of Medicine at Mount Sinai, 1470 Madison Ave., 9-119, New York, NY 10029, USA; Department of Geriatrics, Icahn School of Medicine at Mount Sinai, 1470 Madison Ave., 9-119, New York, NY 10029, USA.
| |
Collapse
|
29
|
Striatal Activity and Reward Relativity: Neural Signals Encoding Dynamic Outcome Valuation. eNeuro 2016; 3:eN-NWR-0022-16. [PMID: 27822506 PMCID: PMC5089537 DOI: 10.1523/eneuro.0022-16.2016] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2016] [Revised: 10/06/2016] [Accepted: 10/07/2016] [Indexed: 11/21/2022] Open
Abstract
The striatum is a key brain region involved in reward processing. Striatal activity has been linked to encoding reward magnitude and integrating diverse reward outcome information. Recent work has supported the involvement of striatum in the valuation of outcomes. The present work extends this idea by examining striatal activity during dynamic shifts in value that include different levels and directions of magnitude disparity. A novel task was used to produce diverse relative reward effects on a chain of instrumental action. Rats (Rattus norvegicus) were trained to respond to cues associated with specific outcomes varying by food pellet magnitude. Animals were exposed to single-outcome sessions followed by mixed-outcome sessions, and neural activity was compared among identical outcome trials from the different behavioral contexts. Results recording striatal activity show that neural responses to different task elements reflect incentive contrast as well as other relative effects that involve generalization between outcomes or possible influences of outcome variety. The activity that was most prevalent was linked to food consumption and post-food consumption periods. Relative encoding was sensitive to magnitude disparity. A within-session analysis showed strong contrast effects that were dependent upon the outcome received in the immediately preceding trial. Significantly higher numbers of responses were found in ventral striatum linked to relative outcome effects. Our results support the idea that relative value can incorporate diverse relationships, including comparisons from specific individual outcomes to general behavioral contexts. The striatum contains these diverse relative processes, possibly enabling both a higher information yield concerning value shifts and a greater behavioral flexibility.
Collapse
|
30
|
Sánchez-Fuentes A, Marichal-Cancino BA, Méndez-Díaz M, Becerril-Meléndez AL, Ruiz-Contreras AE, Prospéro-Garcia O. mGluR1/5 activation in the lateral hypothalamus increases food intake via the endocannabinoid system. Neurosci Lett 2016; 631:104-108. [PMID: 27542344 DOI: 10.1016/j.neulet.2016.08.020] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2016] [Revised: 07/14/2016] [Accepted: 08/13/2016] [Indexed: 11/17/2022]
Abstract
Mounting evidence has shown that glutamatergic and endocannabinoid systems in the hypothalamus regulate mammalian food intake. Stimulation of hypothalamic mGluR1/5 and CB1 receptors induces hyperphagia suggesting a possible interaction between these systems to control food intake. In addition, synthesis of endocannabinoids has been reported after mGluR1/5 stimulation in the brain. The aim of this study was to examine the potential cannabinergic activity in the food intake induction by lateral hypothalamic stimulation of mGluR1/5. Wistar albino male rats received bilateral infusions in the lateral hypothalamus (LH) of: (i) vehicle; (ii) (RS)-2-Chloro-5-hidroxyphenylglycine (CHPG; mGluR1/5 agonist); (iii) 2-AG (CB1 endogenous agonist); (iv) AM251 (CB1 antagonist); (v) tetrahydrolipstatin (THL, 1.2μg; diacyl-glycerol lipase inhibitor); and (vi) combinations of CHPG + with the other aforementioned drugs. Food intake was evaluated the first two hours after drug administration. CHPG significantly increased food intake; whereas CHPG in combination with a dose of 2-AG (with no effects on food intake) greatly increased food ingestion compared to CHPG alone. The increase induced by CHPG in food intake was prevented with AM251 or THL. These results suggest that activation of mGluR1/5 in the lateral hypothalamus induces an orexigenic effect via activation of the endocannabinoid system.
Collapse
Affiliation(s)
- Asai Sánchez-Fuentes
- Grupo de Neurociencias, Laboratorio de Cannabinoides, Departamento de Fisiología, Facultad de Medicina, Universidad Nacional Autónoma de México, Mexico
| | - Bruno A Marichal-Cancino
- Grupo de Neurociencias, Laboratorio de Cannabinoides, Departamento de Fisiología, Facultad de Medicina, Universidad Nacional Autónoma de México, Mexico
| | - Mónica Méndez-Díaz
- Grupo de Neurociencias, Laboratorio de Cannabinoides, Departamento de Fisiología, Facultad de Medicina, Universidad Nacional Autónoma de México, Mexico
| | - Alline L Becerril-Meléndez
- Grupo de Neurociencias, Laboratorio de Cannabinoides, Departamento de Fisiología, Facultad de Medicina, Universidad Nacional Autónoma de México, Mexico
| | - Alejandra E Ruiz-Contreras
- Lab. Neurogenomica Cognitiva, Coord. Psicobiología y Neurociencias, Fac. Psicologia, Universidad Nacional Autónoma de México, México D.F., Mexico
| | - Oscar Prospéro-Garcia
- Grupo de Neurociencias, Laboratorio de Cannabinoides, Departamento de Fisiología, Facultad de Medicina, Universidad Nacional Autónoma de México, Mexico.
| |
Collapse
|
31
|
Genné-Bacon EA, Trinko JR, DiLeone RJ. Innate Fear-Induced Weight Regulation in the C57BL/6J Mouse. Front Behav Neurosci 2016; 10:132. [PMID: 27458352 PMCID: PMC4930939 DOI: 10.3389/fnbeh.2016.00132] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2016] [Accepted: 06/13/2016] [Indexed: 01/01/2023] Open
Abstract
Regulation of body weight is an important strategy for small prey animals to avoid capture. Field and laboratory studies have shown that prey animals reduce body size when subjected to long-term predator stimuli. However, the causes of predator-induced weight regulation are highly variable and the underlying mechanisms remain unclear. Understanding this phenomenon is important for gaining a better understanding of how animals regulate body weight under ethologically relevant conditions and has implications for obesity. Here we expose inbred C57BL/6J mice to a fear-inducing odorant (2,4,5-trimethylthiazole; mT) to model predation-induced weight regulation. Eight week-old mice were put on a 45% high fat diet (HFD) or chow diet (5% fat) and exposed daily to mT, an equally aversive dose of butyric acid (BA), or a neutral control scent (almond). mT-exposed mice in both diet groups gained significantly less weight over a 6-week period than BA-exposed mice. This differential weight gain appears unlikely to be due to differences in food intake and activity level, or brown adipose thermogenesis between the mT and BA groups. However, following chronic mT exposure we find increases in ΔFosB protein, a marker for long-term neural plasticity, in the dorsomedial hypothalamus (DMH)-an area previously implicated in chronic stress and defensive responses, as well as weight regulation. This study establishes a simplified and robust laboratory model of predation-mediated weight regulation with inbred lab mice and fear-inducing odor, and suggests a likely, yet undetermined, metabolic adaptation as contributing to this response.
Collapse
Affiliation(s)
- Elizabeth A Genné-Bacon
- Division of Molecular Psychiatry, Ribicoff Research Facilities, Department of Psychiatry, Yale University School of MedicineNew Haven, CT, USA; Department of Genetics, Yale University School of MedicineNew Haven, CT, USA
| | - Joseph R Trinko
- Division of Molecular Psychiatry, Ribicoff Research Facilities, Department of Psychiatry, Yale University School of Medicine New Haven, CT, USA
| | - Ralph J DiLeone
- Division of Molecular Psychiatry, Ribicoff Research Facilities, Department of Psychiatry, Yale University School of Medicine New Haven, CT, USA
| |
Collapse
|
32
|
Karlsson C, Rehman F, Damadzic R, Atkins AL, Schank JR, Gehlert DR, Steensland P, Thorsell A, Heilig M. The melanin-concentrating hormone-1 receptor modulates alcohol-induced reward and DARPP-32 phosphorylation. Psychopharmacology (Berl) 2016; 233:2355-63. [PMID: 27044354 DOI: 10.1007/s00213-016-4285-y] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/09/2015] [Accepted: 03/22/2016] [Indexed: 11/24/2022]
Abstract
RATIONALE Melanin-concentrating hormone (MCH) is involved in the regulation of food intake and has recently been associated with alcohol-related behaviors. Blockade of MCH-1 receptors (MCH1-Rs) attenuates operant alcohol self-administration and decreases cue-induced reinstatement, but the mechanism through which the MCH1-R influences these behaviors remains unknown. MCH1-Rs are highly expressed in the nucleus accumbens shell (NAcSh) where they are co-expressed with dopamine (DA) receptors. MCH has been shown to potentiate responses to dopamine and to increase phosphorylation of DARPP-32, an intracellular marker of DA receptor activation, in the NAcSh. METHODS In the present study, we investigated the role of the MCH1-R in alcohol reward using the conditioned place preference (CPP) paradigm. We then used immunohistochemistry (IHC) to assess activation of downstream signaling after administration of a rewarding dose of alcohol. RESULTS We found that alcohol-induced CPP was markedly decreased in mice with a genetic deletion of the MCH1-R as well as after pharmacological treatment with an MCH1-R antagonist, GW803430. In contrast, an isocaloric dose of dextrose did not produce CPP. The increase in DARPP-32 phosphorylation seen in wildtype (WT) mice after acute alcohol administration in the NAcSh was markedly reduced in MCH1-R knock-out (KO) mice. CONCLUSION Our results suggest that MCH1-Rs regulate the rewarding properties of alcohol through interactions with signaling cascades downstream of DA receptors in the NAcSh.
Collapse
Affiliation(s)
- Camilla Karlsson
- Department of Clinical and Experimental Medicine, Linkopings University, Linkoping, Sweden
| | - Faazal Rehman
- Laboratory of Clinical and Translational Studies, National Institute on Alcohol Abuse and Alcoholism (NIAAA), National Institutes of Health (NIH), Bethesda, MD, USA
| | - Ruslan Damadzic
- Laboratory of Clinical and Translational Studies, National Institute on Alcohol Abuse and Alcoholism (NIAAA), National Institutes of Health (NIH), Bethesda, MD, USA
| | - Alison L Atkins
- Department of Clinical and Experimental Medicine, Linkopings University, Linkoping, Sweden
| | - Jesse R Schank
- Department of Physiology and Pharmacology, University of Georgia, Athens, GA, USA
| | - Donald R Gehlert
- Neuroscience and Endocrine Discovery Research, Lilly Research Laboratories, a Division of Eli Lilly and Company, Indianapolis, IN, USA
| | - Pia Steensland
- Department of Clinical Neuroscience, Karolinska Institutet, Stockholm, Sweden
| | - Annika Thorsell
- Department of Clinical and Experimental Medicine, Linkopings University, Linkoping, Sweden
| | - Markus Heilig
- Department of Clinical and Experimental Medicine, Linkopings University, Linkoping, Sweden.
| |
Collapse
|
33
|
Lateral Hypothalamus GABAergic Neurons Modulate Consummatory Behaviors Regardless of the Caloric Content or Biological Relevance of the Consumed Stimuli. Neuropsychopharmacology 2016; 41:1505-12. [PMID: 26442599 PMCID: PMC4832010 DOI: 10.1038/npp.2015.304] [Citation(s) in RCA: 77] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/04/2015] [Revised: 09/03/2015] [Accepted: 10/01/2015] [Indexed: 02/05/2023]
Abstract
It was recently reported that activation of a subset of lateral hypothalamus (LH) GABAergic neurons induced both appetitive (food-seeking) and consummatory (eating) behaviors in vGat-ires-cre mice, while inhibition or deletion of GABAergic neurons blunted these behaviors. As food and caloric-dense liquid solutions were used, the data reported suggest that these LH GABAergic neurons may modulate behaviors that function to maintain homeostatic caloric balance. Here we report that chemogenetic activation of this GABAergic population in vGat-ires-cre mice increased consummatory behavior directed at any available stimulus, including those entailing calories (food, sucrose, and ethanol), those that do not (saccharin and water), and those lacking biological relevance (wood). Chemogenetic inhibition of these neurons attenuated consummatory behaviors. These data indicate that LH GABAergic neurons modulate consummatory behaviors regardless of the caloric content or biological relevance of the consumed stimuli.
Collapse
|
34
|
Tabe-Bordbar S, Anastasio TJ. Computational Analysis of the Hypothalamic Control of Food Intake. Front Comput Neurosci 2016; 10:27. [PMID: 27199725 PMCID: PMC4844610 DOI: 10.3389/fncom.2016.00027] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2015] [Accepted: 03/14/2016] [Indexed: 12/01/2022] Open
Abstract
Food-intake control is mediated by a heterogeneous network of different neural subtypes, distributed over various hypothalamic nuclei and other brain structures, in which each subtype can release more than one neurotransmitter or neurohormone. The complexity of the interactions of these subtypes poses a challenge to understanding their specific contributions to food-intake control, and apparent consistencies in the dataset can be contradicted by new findings. For example, the growing consensus that arcuate nucleus neurons expressing Agouti-related peptide (AgRP neurons) promote feeding, while those expressing pro-opiomelanocortin (POMC neurons) suppress feeding, is contradicted by findings that low AgRP neuron activity and high POMC neuron activity can be associated with high levels of food intake. Similarly, the growing consensus that GABAergic neurons in the lateral hypothalamus suppress feeding is contradicted by findings suggesting the opposite. Yet the complexity of the food-intake control network admits many different network behaviors. It is possible that anomalous associations between the responses of certain neural subtypes and feeding are actually consistent with known interactions, but their effect on feeding depends on the responses of the other neural subtypes in the network. We explored this possibility through computational analysis. We made a computer model of the interactions between the hypothalamic and other neural subtypes known to be involved in food-intake control, and optimized its parameters so that model behavior matched observed behavior over an extensive test battery. We then used specialized computational techniques to search the entire model state space, where each state represents a different configuration of the responses of the units (model neural subtypes) in the network. We found that the anomalous associations between the responses of certain hypothalamic neural subtypes and feeding are actually consistent with the known structure of the food-intake control network, and we could specify the ways in which the anomalous configurations differed from the expected ones. By analyzing the temporal relationships between different states we identified the conditions under which the anomalous associations can occur, and these stand as model predictions.
Collapse
Affiliation(s)
- Shayan Tabe-Bordbar
- Computational Neurobiology Laboratory, Department of Molecular and Integrative Physiology, Beckman Institute, University of Illinois at Urbana-Champaign Urbana, IL, USA
| | - Thomas J Anastasio
- Computational Neurobiology Laboratory, Department of Molecular and Integrative Physiology, Beckman Institute, University of Illinois at Urbana-Champaign Urbana, IL, USA
| |
Collapse
|
35
|
Reichelt AC, Westbrook RF, Morris MJ. Integration of reward signalling and appetite regulating peptide systems in the control of food-cue responses. Br J Pharmacol 2015; 172:5225-38. [PMID: 26403657 DOI: 10.1111/bph.13321] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2015] [Revised: 07/28/2015] [Accepted: 08/27/2015] [Indexed: 12/24/2022] Open
Abstract
Understanding the neurobiological substrates that encode learning about food-associated cues and how those signals are modulated is of great clinical importance especially in light of the worldwide obesity problem. Inappropriate or maladaptive responses to food-associated cues can promote over-consumption, leading to excessive energy intake and weight gain. Chronic exposure to foods rich in fat and sugar alters the reinforcing value of foods and weakens inhibitory neural control, triggering learned, but maladaptive, associations between environmental cues and food rewards. Thus, responses to food-associated cues can promote cravings and food-seeking by activating mesocorticolimbic dopamine neurocircuitry, and exert physiological effects including salivation. These responses may be analogous to the cravings experienced by abstaining drug addicts that can trigger relapse into drug self-administration. Preventing cue-triggered eating may therefore reduce the over-consumption seen in obesity and binge-eating disorder. In this review we discuss recent research examining how cues associated with palatable foods can promote reward-based feeding behaviours and the potential involvement of appetite-regulating peptides including leptin, ghrelin, orexin and melanin concentrating hormone. These peptide signals interface with mesolimbic dopaminergic regions including the ventral tegmental area to modulate reactivity to cues associated with palatable foods. Thus, a novel target for anti-obesity therapeutics is to reduce non-homeostatic, reward driven eating behaviour, which can be triggered by environmental cues associated with highly palatable, fat and sugar rich foods.
Collapse
Affiliation(s)
- A C Reichelt
- School of Psychology, UNSW Sydney, Sydney, UNSW, Australia.,School of Medical Sciences, UNSW Sydney, Sydney, UNSW, Australia
| | - R F Westbrook
- School of Psychology, UNSW Sydney, Sydney, UNSW, Australia
| | - M J Morris
- School of Medical Sciences, UNSW Sydney, Sydney, UNSW, Australia
| |
Collapse
|
36
|
Melanin-concentrating hormone neurons release glutamate for feedforward inhibition of the lateral septum. J Neurosci 2015; 35:3644-51. [PMID: 25716862 DOI: 10.1523/jneurosci.4187-14.2015] [Citation(s) in RCA: 67] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Melanin-concentrating hormone (MCH) regulates vital physiological functions, including energy balance and sleep. MCH cells are thought to be GABAergic, releasing GABA to inhibit downstream targets. However, there is little experimental support for this paradigm. To better understand the synaptic mechanisms of mouse MCH neurons, we performed neuroanatomical mapping and characterization followed by optogenetics to test their functional connectivity at downstream targets. Synaptophysin-mediated projection mapping showed that the lateral septal nucleus (LS) contained the densest accumulation of MCH nerve terminals. We then expressed channel rhodopsin-2 in MCH neurons and photostimulated MCH projections to determine their effect on LS activity. Photostimulation of MCH projections evoked a monosynaptic glutamate release in the LS. Interestingly, this led to a feedforward inhibition that depressed LS firing by a robust secondary GABA release. This study presents a circuit analysis between MCH and LS neurons and confirms their functional connection via monosynaptic and polysynaptic pathways. Our findings indicate that MCH neurons are not exclusively GABAergic and reveal a glutamate-mediated, feedforward mechanism that inhibits LS cells.
Collapse
|
37
|
van den Heuvel JK, Furman K, Gumbs MC, Eggels L, Opland DM, Land BB, Kolk SM, Narayanan N, Fliers E, Kalsbeek A, DiLeone RJ, la Fleur SE. Neuropeptide Y activity in the nucleus accumbens modulates feeding behavior and neuronal activity. Biol Psychiatry 2015; 77:633-41. [PMID: 25109664 PMCID: PMC4295932 DOI: 10.1016/j.biopsych.2014.06.008] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/27/2013] [Revised: 05/23/2014] [Accepted: 06/11/2014] [Indexed: 01/02/2023]
Abstract
BACKGROUND Neuropeptide Y (NPY) is a hypothalamic neuropeptide that plays a prominent role in feeding and energy homeostasis. Expression of the NPY Y1 receptor (Y1R) is highly concentrated in the nucleus accumbens (Acb), a region important in the regulation of palatable feeding. In this study, we performed a number of experiments to investigate the actions of NPY in the Acb. METHODS First, we determined caloric intake and food choice after bilateral administration of NPY in the Acb in rats on a free-choice diet of saturated fat, 30% sucrose solution, and standard chow and whether this was mediated by the Y1R. Second, we measured the effect of intra-Acb NPY on neuronal activity using in vivo electrophysiology. Third, we examined co-localization of Y1R with enkephalin and dynorphin neurons and the effect of NPY on preproenkephalin messenger RNA levels in the striatum using fluorescent and radioactive in situ hybridization. Finally, using retrograde tracing, we examined whether NPY neurons in the arcuate nucleus projected to the Acb. RESULTS In rats on the free-choice, high-fat, high-sugar diet, intra-Acb NPY increased intake of fat, but not sugar or chow, and this was mediated by the Y1R. Intra-Acb NPY reduced neuronal firing, as well as preproenkephalin messenger RNA expression in the striatum. Moreover, Acb enkephalin neurons expressed Y1R and arcuate nucleus NPY neurons projected to the Acb. CONCLUSIONS NPY reduces neuronal firing in the Acb resulting in increased palatable food intake. Together, our neuroanatomical, pharmacologic, and neuronal activity data support a role and mechanism for intra-Acb NPY-induced fat intake.
Collapse
|
38
|
Brown JA, Woodworth HL, Leinninger GM. To ingest or rest? Specialized roles of lateral hypothalamic area neurons in coordinating energy balance. Front Syst Neurosci 2015; 9:9. [PMID: 25741247 PMCID: PMC4332303 DOI: 10.3389/fnsys.2015.00009] [Citation(s) in RCA: 65] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2014] [Accepted: 01/15/2015] [Indexed: 12/26/2022] Open
Abstract
Survival depends on an organism’s ability to sense nutrient status and accordingly regulate intake and energy expenditure behaviors. Uncoupling of energy sensing and behavior, however, underlies energy balance disorders such as anorexia or obesity. The hypothalamus regulates energy balance, and in particular the lateral hypothalamic area (LHA) is poised to coordinate peripheral cues of energy status and behaviors that impact weight, such as drinking, locomotor behavior, arousal/sleep and autonomic output. There are several populations of LHA neurons that are defined by their neuropeptide content and contribute to energy balance. LHA neurons that express the neuropeptides melanin-concentrating hormone (MCH) or orexins/hypocretins (OX) are best characterized and these neurons play important roles in regulating ingestion, arousal, locomotor behavior and autonomic function via distinct neuronal circuits. Recently, another population of LHA neurons containing the neuropeptide Neurotensin (Nts) has been implicated in coordinating anorectic stimuli and behavior to regulate hydration and energy balance. Understanding the specific roles of MCH, OX and Nts neurons in harmonizing energy sensing and behavior thus has the potential to inform pharmacological strategies to modify behaviors and treat energy balance disorders.
Collapse
Affiliation(s)
- Juliette A Brown
- Department of Pharmacology and Toxicology, Michigan State University East Lansing, MI, USA ; Center for Integrative Toxicology East Lansing, MI, USA
| | | | - Gina M Leinninger
- Center for Integrative Toxicology East Lansing, MI, USA ; Department of Physiology, Michigan State University East Lansing, MI, USA
| |
Collapse
|
39
|
Urstadt KR, Stanley BG. Direct hypothalamic and indirect trans-pallidal, trans-thalamic, or trans-septal control of accumbens signaling and their roles in food intake. Front Syst Neurosci 2015; 9:8. [PMID: 25741246 PMCID: PMC4327307 DOI: 10.3389/fnsys.2015.00008] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2014] [Accepted: 01/15/2015] [Indexed: 01/01/2023] Open
Abstract
Due in part to the increasing incidence of obesity in developed nations, recent research aims to elucidate neural circuits that motivate humans to overeat. Earlier research has described how the nucleus accumbens shell (AcbSh) motivates organisms to feed by activating neuronal populations in the lateral hypothalamus (LH). However, more recent research suggests that the LH may in turn communicate with the AcbSh, both directly and indirectly, to re-tune the motivation to consume foods with homeostatic and food-related sensory signals. Here, we discuss the functional and anatomical evidence for an LH to AcbSh connection and its role in eating behaviors. The LH appears to modulate Acb activity directly, using neurotransmitters such as hypocretin/orexin or melanin concentrating hormone (MCH). The LH also indirectly regulates AcbSh activity through certain subcortical "relay" regions, such as the lateral septum (LS), ventral pallidum (VP), and paraventricular thalamus, using a variety of neurotransmitters. This review aims to summarize studies on these topics and outline a model by which LH circuits processing energy balance can modulate AcbSh neural activity to regulate feeding behavior.
Collapse
Affiliation(s)
- Kevin R Urstadt
- Department of Psychology, University of Michigan Ann Arbor, MI, USA
| | - B Glenn Stanley
- Departments of Psychology and Cell Biology and Neuroscience, University of California - Riverside Riverside, CA, USA
| |
Collapse
|
40
|
High on food: the interaction between the neural circuits for feeding and for reward. ACTA ACUST UNITED AC 2015; 10:165-176. [PMID: 29750082 DOI: 10.1007/s11515-015-1348-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Hunger, mostly initiated by a deficiency in energy, induces food seeking and intake. However, the drive toward food is not only regulated by physiological needs, but is motivated by the pleasure derived from ingestion of food, in particular palatable foods. Therefore, feeding is viewed as an adaptive motivated behavior that involves integrated communication between homeostatic feeding circuits and reward circuits. The initiation and termination of a feeding episode are instructed by a variety of neuronal signals, and maladaptive plasticity in almost any component of the network may lead to the development of pathological eating disorders. In this review we will summarize the latest understanding of how the feeding circuits and reward circuits in the brain interact. We will emphasize communication between the hypothalamus and the mesolimbic dopamine system and highlight complexities, discrepancies, open questions and future directions for the field.
Collapse
|
41
|
Haemmerle CAS, Campos AMP, Bittencourt JC. Melanin-concentrating hormone inputs to the nucleus accumbens originate from distinct hypothalamic sources and are apposed to GABAergic and cholinergic cells in the Long-Evans rat brain. Neuroscience 2015; 289:392-405. [PMID: 25613687 DOI: 10.1016/j.neuroscience.2015.01.014] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2014] [Revised: 01/06/2015] [Accepted: 01/09/2015] [Indexed: 01/12/2023]
Abstract
Melanin-concentrating hormone [MCH] is a neuropeptide that modulates several behaviors, such as feeding and reward. Because the hedonic and rewarding features of a food also influence feeding behavior, the nucleus accumbens [Acb] has been highlighted as a key area integrating these roles. Functional data confirm that MCH acts on a subdivision of the Acb; however, considering the importance of finding anatomical and neurochemical data that correlate the previously demonstrated function of MCH, we delineated this investigation based on the following points: (1) Is there a pattern of innervation by MCH fibers regarding the subregions within the Acb? (2) Specifically, which hypothalamic nuclei synthesize MCH and innervate the Acb? (3) Finally, what are the neurochemical identities of the accumbal neurons innervated by MCH inputs? We examined the MCH immunoreactivity [MCH-ir] in the Acb in rat brains using the peroxidase technique. Additionally, after injecting retrograde neuronal tracer [Fluoro-Gold® - FG®] into subdivisions of the Acb [shell or core], we mapped single- or double-labeled cells. Moreover, using a double immunoperoxidase protocol, we investigated the MCH-ir fibers for gamma-aminobutyric acid [GABA]-ir and choline acetyltransferase [ChAT]-ir cells in the shell subdivision of the Acb [AcbSh]. We found that the MCH-ir fibers preferentially innervate the medial AcbSh, particularly the septal pole. This innervation originated from the incerto-hypothalamic area [IHy], internuclear area, lateral hypothalamic area, perifornical area, periventricular nucleus and posterior hypothalamus. Moreover, the IHy has the highest relationship between double/single retrogradely labeled cells [n=5.33±0.66/16±0.93, i.e. 33.33%] in the whole hypothalamus. Furthermore, our data suggest that MCH-ir fibers are in apposition to GABAergic and cholinergic cells in the AcbSh. Therefore, we provide anatomical support to the ongoing functional studies investigating the relation among the hypothalamus, MCH transmission into the Acb and the involvement of known neuronal phenotypes within the AcbSh.
Collapse
Affiliation(s)
- C A S Haemmerle
- Laboratory of Chemical Neuroanatomy, Department of Anatomy, Institute of Biomedical Sciences, University of São Paulo, 05508-000 São Paulo, Brazil.
| | - A M P Campos
- Department of Physiology and Biophysics, Institute of Biomedical Sciences, University of São Paulo, 05508-000 São Paulo, Brazil.
| | - J C Bittencourt
- Laboratory of Chemical Neuroanatomy, Department of Anatomy, Institute of Biomedical Sciences, University of São Paulo, 05508-000 São Paulo, Brazil; Center for Neuroscience and Behavior, Institute of Psychology, University of São Paulo, 05508-000 São Paulo, Brazil.
| |
Collapse
|
42
|
Parks GS, Wang L, Wang Z, Civelli O. Identification of neuropeptide receptors expressed by melanin-concentrating hormone neurons. J Comp Neurol 2014; 522:3817-33. [PMID: 24978951 PMCID: PMC4167928 DOI: 10.1002/cne.23642] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2012] [Revised: 06/17/2014] [Accepted: 06/24/2014] [Indexed: 01/13/2023]
Abstract
Melanin-concentrating hormone (MCH) is a 19-amino-acid cyclic neuropeptide that acts in rodents via the MCH receptor 1 (MCHR1) to regulate a wide variety of physiological functions. MCH is produced by a distinct population of neurons located in the lateral hypothalamus (LH) and zona incerta (ZI), but MCHR1 mRNA is widely expressed throughout the brain. The physiological responses and behaviors regulated by the MCH system have been investigated, but less is known about how MCH neurons are regulated. The effects of most classical neurotransmitters on MCH neurons have been studied, but those of most neuropeptides are poorly understood. To gain insight into how neuropeptides regulate the MCH system, we investigated which neuropeptide receptors are expressed by MCH neurons by using double in situ hybridization. In all, 20 receptors, selected based on either a suspected interaction with the MCH system or demonstrated high expression levels in the LH and ZI, were tested to determine whether they are expressed by MCH neurons. Overall, 11 neuropeptide receptors were found to exhibit significant colocalization with MCH neurons: nociceptin/orphanin FQ opioid receptor (NOP), MCHR1, both orexin receptors (ORX), somatostatin receptors 1 and 2 (SSTR1, SSTR2), kisspeptin recepotor (KissR1), neurotensin receptor 1 (NTSR1), neuropeptide S receptor (NPSR), cholecystokinin receptor A (CCKAR), and the κ-opioid receptor (KOR). Among these receptors, six have never before been linked to the MCH system. Surprisingly, several receptors thought to regulate MCH neurons displayed minimal colocalization with MCH, suggesting that they may not directly regulate the MCH system.
Collapse
Affiliation(s)
- Gregory S. Parks
- Department of Pharmacology, University of California Irvine, Irvine, California 92697
- Department of Developmental and Cell Biology, University of California Irvine, Irvine, California, 92697
| | - Lien Wang
- Department of Pharmacology, University of California Irvine, Irvine, California 92697
| | - Zhiwei Wang
- Department of Pharmacology, University of California Irvine, Irvine, California 92697
| | - Olivier Civelli
- Department of Pharmacology, University of California Irvine, Irvine, California 92697
- Department of Developmental and Cell Biology, University of California Irvine, Irvine, California, 92697
- Department of Pharmaceutical Sciences, University of California Irvine, Irvine, California, 92697
| |
Collapse
|
43
|
Chometton S, Cvetkovic-Lopes V, Houdayer C, Franchi G, Mariot A, Poncet F, Fellmann D, Risold PY. Anatomical organization of MCH connections with the pallidum and dorsal striatum in the rat. Front Syst Neurosci 2014; 8:185. [PMID: 25324738 PMCID: PMC4181234 DOI: 10.3389/fnsys.2014.00185] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2014] [Accepted: 09/11/2014] [Indexed: 12/27/2022] Open
Abstract
Neurons producing the melanin-concentrating hormone (MCH) are distributed in the posterior hypothalamus, but project massively throughout the forebrain. Many aspects regarding the anatomical organization of these projections are still obscure. The present study has two goals: first to characterize the topographical organization of neurons projecting into the cholinergic basal forebrain (globus pallidus, medial septal complex), and second to verify if MCH neurons may indirectly influence the dorsal striatum (caudoputamen) by innervating afferent sources to this structure. In the first series of experiments, the retrograde tracer fluorogold was injected into multiple sites in the pallidal and medial septal regions and the distribution of retrogradely labeled neurons were analyzed in the posterior lateral hypothalamus. In the second series of experiments, fluorogold was injected into the caudoputamen, and the innervation by MCH axons of retrogradely labeled cells was analyzed. Our results revealed that the MCH system is able to interact with the basal nuclei in several different ways. First, MCH neurons provide topographic inputs to the globus pallidus, medial septal complex, and substantia innominata. Second, striatal projecting neurons in the cortex, thalamus, and substantia nigra presumably receive only sparse inputs from MCH neurons. Third, the subthalamic nucleus is heavily innervated by MCH projections, thus, presumably serves as one important intermediate station to mediate MCH influence on other parts of the basal nuclei.
Collapse
Affiliation(s)
| | | | | | | | | | | | | | - Pierre-Yves Risold
- EA3922, SFR FED 4234, UFR Sciences Médicales et Pharmaceutiques, Université de Franche-ComtéBesançon, France
| |
Collapse
|
44
|
Chometton S, Franchi G, Houdayer C, Mariot A, Poncet F, Fellmann D, Tillet Y, Risold PY. Different distributions of preproMCH and hypocretin/orexin in the forebrain of the pig (Sus scrofa domesticus). J Chem Neuroanat 2014; 61-62:72-82. [PMID: 25124772 DOI: 10.1016/j.jchemneu.2014.08.001] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2014] [Revised: 08/01/2014] [Accepted: 08/01/2014] [Indexed: 12/27/2022]
Abstract
Neurons producing melanin-concentrating hormone (MCH) or hypocretin/orexin (Hcrt) have been implicated in the sleep/wake cycle and feeding behavior. Sleep and feeding habits vary greatly among mammalian species, depending in part of the prey/predatory status of animals. However, the distribution of both peptides has been described in only a limited number of species. In this work, we describe the distribution of MCH neurons in the brain of the domestic pig. Using in situ hybridization and immunohistochemistry, their cell bodies are shown to be located in the posterior lateral hypothalamic area (LHA), as expected. They form a dense cluster ventro-lateral to the fornix while only scattered cells are present dorsal to this tract. By comparison, Hcrt cell bodies are located mainly dorsal to the fornix. Therefore, the two populations of neurons display complementary distributions in the posterior LHA. MCH projections are, as indicated by MCH-positive axons, very abundant in all cortical fields ventral to the rhinal sulcus, as well as in the lateral, basolateral and basomedial amygdala. In contrast, most of the isocortex is sparsely innervated. To conclude, the distribution of MCH cell bodies and projections shows some very specific features in the pig brain, that are clearly different of that described in the rat, mouse or human. In contrast, the Hcrt pattern seems more similar to that in these species, i.e. more conserved. These results suggest that the LHA anatomic organization shows some very significant interspecies differences, which may be related to the different behavioral repertoires of animals with regard to feeding and sleep/wake cycles.
Collapse
Affiliation(s)
- S Chometton
- EA3922, UFR Sciences Médicales et Pharmaceutiques, SFR-FED 4234, Université de Franche-Comté, Besançon 25000, France
| | - G Franchi
- EA3922, UFR Sciences Médicales et Pharmaceutiques, SFR-FED 4234, Université de Franche-Comté, Besançon 25000, France
| | - C Houdayer
- EA3922, UFR Sciences Médicales et Pharmaceutiques, SFR-FED 4234, Université de Franche-Comté, Besançon 25000, France
| | - A Mariot
- EA3922, UFR Sciences Médicales et Pharmaceutiques, SFR-FED 4234, Université de Franche-Comté, Besançon 25000, France
| | - F Poncet
- EA3922, UFR Sciences Médicales et Pharmaceutiques, SFR-FED 4234, Université de Franche-Comté, Besançon 25000, France
| | - D Fellmann
- EA3922, UFR Sciences Médicales et Pharmaceutiques, SFR-FED 4234, Université de Franche-Comté, Besançon 25000, France
| | - Y Tillet
- UMR 7247 INRA/CNRS/Université François Rabelais de Tours/IFCE, SFR-FED 4226, Centre INRA Val de Loire, Nouzilly, Tours 37380, France
| | - P Y Risold
- EA3922, UFR Sciences Médicales et Pharmaceutiques, SFR-FED 4234, Université de Franche-Comté, Besançon 25000, France.
| |
Collapse
|
45
|
The neuroanatomical function of leptin in the hypothalamus. J Chem Neuroanat 2014; 61-62:207-20. [PMID: 25007719 DOI: 10.1016/j.jchemneu.2014.05.004] [Citation(s) in RCA: 54] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2013] [Revised: 05/09/2014] [Accepted: 05/28/2014] [Indexed: 02/07/2023]
Abstract
The anorexigenic hormone leptin plays an important role in the control of food intake and feeding-related behavior, for an important part through its action in the hypothalamus. The adipose-derived hormone modulates a complex network of several intercommunicating orexigenic and anorexigenic neuropeptides in the hypothalamus to reduce food intake and increase energy expenditure. In this review we present an updated overview of the functional role of leptin in respect to feeding and feeding-related behavior per distinct hypothalamic nuclei. In addition to the arcuate nucleus, which is a major leptin sensitive hub, leptin-responsive neurons in other hypothalamic nuclei, including the, dorsomedial-, ventromedial- and paraventricular nucleus and the lateral hypothalamic area, are direct targets of leptin. However, leptin also modulates hypothalamic neurons in an indirect manner, such as via the melanocortin system. The dissection of the complexity of leptin's action on the networks involved in energy balance is subject of recent and future studies. A full understanding of the role of hypothalamic leptin in the regulation of energy balance requires cell-specific manipulation using of conditional deletion and expression of leptin receptors. In addition, optogenetic and pharmacogenetic tools in combination with other pharmacological (such as the recent discovery of a leptin receptor antagonist) and neuronal tracing techniques to map the circuit, will be helpful to understand the role of leptin receptor expressing neurons. Better understanding of these circuits and the involvement of leptin could provide potential sites for therapeutic interventions in obesity and metabolic diseases characterized by dysregulation of energy balance.
Collapse
|
46
|
Mohammadi M, Bergado-Acosta JR, Fendt M. Relief learning is distinguished from safety learning by the requirement of the nucleus accumbens. Behav Brain Res 2014; 272:40-5. [PMID: 24995614 DOI: 10.1016/j.bbr.2014.06.053] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2014] [Revised: 06/23/2014] [Accepted: 06/24/2014] [Indexed: 10/25/2022]
Abstract
Aversive events induce aversive memories (fear learning) and can also establish appetitive memories. This is the case for cues associated with the cessation of an aversive event (relief learning) or occurring in an explicitly unpaired fashion (safety learning). However, the neural basis of relief and safety learning is poorly understood. In particular, it is not clear whether relief learning and safety learning are neuronally distinct. In the present study, we ask whether the nucleus accumbens is required for the acquisition of relief- and/or safety memory. Temporary inactivation of the nucleus accumbens by local injections of the GABA-A receptor agonist muscimol during the learning session abolished relief learning whereas safety learning was not affected. Thus, the requirement for a functional nucleus accumbens distinguishes relief from safety learning, showing that these two forms of learning are neuronally distinct.
Collapse
Affiliation(s)
- Milad Mohammadi
- Institute for Pharmacology and Toxicology, Otto-von-Guericke University Magdeburg, Magdeburg, Germany; Integrative Neuroscience Program, Otto-von-Guericke University Magdeburg, Magdeburg, Germany
| | - Jorge R Bergado-Acosta
- Institute for Pharmacology and Toxicology, Otto-von-Guericke University Magdeburg, Magdeburg, Germany
| | - Markus Fendt
- Institute for Pharmacology and Toxicology, Otto-von-Guericke University Magdeburg, Magdeburg, Germany; Center of Behavioral Brain Sciences, Otto-von-Guericke University Magdeburg, Magdeburg, Germany.
| |
Collapse
|
47
|
Pandit R, Luijendijk MCM, Vanderschuren LJMJ, la Fleur SE, Adan RAH. Limbic substrates of the effects of neuropeptide Y on intake of and motivation for palatable food. Obesity (Silver Spring) 2014; 22:1216-9. [PMID: 24500791 DOI: 10.1002/oby.20718] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/23/2013] [Revised: 01/28/2014] [Accepted: 01/29/2014] [Indexed: 11/08/2022]
Abstract
OBJECTIVE Neuropeptide Y (NPY), given centrally augments food intake and the motivation to work for palatable food. Here, the brain regions were identified through which NPY increases food intake and motivation. METHODS NPY was infused into three brain regions implicated in food intake and motivation: the lateral hypothalamus (LH), nucleus accumbens shell (NAc), and ventral tegmental area (VTA). Motivation for sucrose was assessed using a progressive-ratio schedule of reinforcement in which the effort to obtain successive rewards increased incrementally. To disentangle the effects of NPY on motivation for palatable food from food consumption, free-feeding experiments were performed in which animals had ad libitum access to sucrose pellets. RESULTS Infusion of NPY into either VTA or NAc increased the motivation to respond for sucrose, whereas infusion of NPY in either NAc or LH increased sucrose consumption. In addition, the effect of intra-VTA NPY on motivation for food was attenuated after pretreatment with the dopamine receptor antagonist alpha-flupenthixol. CONCLUSIONS Specific limbic substrates through which NPY influences consumption of and motivation for palatable food were identified by these data. The motivational effects of NPY are exerted through the VTA, its consummatory effects through the LH, and the NAc is involved in both.
Collapse
Affiliation(s)
- Rahul Pandit
- Department of Translational Neuroscience Brain Center Rudolf Magnus, University Medical Center Utrecht, Utrecht, The Netherlands
| | | | | | | | | |
Collapse
|
48
|
Land BB, Brayton CE, Furman KE, Lapalombara Z, Dileone RJ. Optogenetic inhibition of neurons by internal light production. Front Behav Neurosci 2014; 8:108. [PMID: 24744708 PMCID: PMC3978322 DOI: 10.3389/fnbeh.2014.00108] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2014] [Accepted: 03/13/2014] [Indexed: 12/16/2022] Open
Abstract
Optogenetics is an extremely powerful tool for selective neuronal activation/inhibition and dissection of neural circuits. However, a limitation of in vivo optogenetics is that an animal must be tethered to an optical fiber for delivery of light. Here, we describe a new method for in vivo, optogenetic inhibition of neural activity using an internal, animal-generated light source based on firefly luciferase. Two adeno-associated viruses encoding luciferase were tested and both produced concentration-dependent light after administration of the substrate, luciferin. Mice were co-infected with halorhodopsin- and luciferase-expressing viruses in the striatum, and luciferin administration significantly reduced Fos activity compared to control animals infected with halorhodopsin only. Recordings of neuronal activity in behaving animals confirmed that firing was greatly reduced after luciferin administration. Finally, amphetamine-induced locomotor activity was reduced in halorhodopsin/luciferase mice pre-injected with luciferin compared to controls. This demonstrates that virally encoded luciferase is able to generate sufficient light to activate halorhodopsin and suppress neural activity and change behavior. This approach could be used to generate inhibition in response to activation of specific molecular pathways.
Collapse
Affiliation(s)
- Benjamin B Land
- Department of Psychiatry, Yale University School of Medicine New Haven, CT, USA
| | - Catherine E Brayton
- Department of Psychiatry, Yale University School of Medicine New Haven, CT, USA
| | - Kara E Furman
- Department of Psychiatry, Yale University School of Medicine New Haven, CT, USA
| | - Zoe Lapalombara
- Department of Psychiatry, Yale University School of Medicine New Haven, CT, USA
| | - Ralph J Dileone
- Department of Psychiatry, Yale University School of Medicine New Haven, CT, USA
| |
Collapse
|
49
|
Zhang LN, Sinclair R, Selman C, Mitchell S, Morgan D, Clapham JC, Speakman JR. Effects of a specific MCHR1 antagonist (GW803430) on energy budget and glucose metabolism in diet-induced obese mice. Obesity (Silver Spring) 2014; 22:681-90. [PMID: 23512845 DOI: 10.1002/oby.20418] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/27/2012] [Accepted: 02/01/2013] [Indexed: 11/08/2022]
Abstract
OBJECTIVE The melanin-concentrating hormone (MCH) is a centrally acting peptide implicated in the regulation of energy homeostasis and body weight, although its role in glucose homeostasis is uncertain. Our objective was to determine effects of MCHR1 antagonism on energy budgets and glucose homeostasis in mice. METHODS Effects of chronic oral administration of a specific MCHR1 antagonist (GW803430) on energy budgets and glucose homeostasis in diet-induced obese (DIO) C57BL/6J mice were examined. RESULTS Oral administration of GW803430 for 30 days reduced food intake, body weight, and body fat. Circulating leptin and triglycerides were reduced but insulin and nonesterified fatty acids were unaffected. Despite weight loss there was no improvement in glucose homeostasis (insulin levels and intraperitoneal glucose tolerance tests). On day 4-6, mice receiving MCHR1 antagonist exhibited decreased metabolisable energy intake and increased daily energy expenditure. However these effects had disappeared by day 22-24. Physical activity during the dark phase was increased by MCHR1 antagonist treatment throughout the 30-day treatment. CONCLUSIONS GW803430 produced a persistent anti-obesity effect due to both a decrease in energy intake and an increase in energy expenditure via physical activity but did not improve glucose homeostasis.
Collapse
Affiliation(s)
- Li-Na Zhang
- Integrative Physiology, Institute of Biological Sciences, University of Aberdeen, Aberdeen, Scotland, UK
| | | | | | | | | | | | | |
Collapse
|
50
|
Amphetamine reward in food restricted mice lacking the melanin-concentrating hormone receptor-1. Behav Brain Res 2014; 262:14-20. [PMID: 24412349 DOI: 10.1016/j.bbr.2013.12.052] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2013] [Revised: 12/28/2013] [Accepted: 12/30/2013] [Indexed: 01/04/2023]
Abstract
Chronic food restriction (FR) and maintenance of low body weight have long been known to increase the rewarding and motor-activating effects of addictive drugs. However, the neurobiological mechanisms through which FR potentiates drug reward remain largely unknown. Melanin-concentrating hormone (MCH) signaling could be one of these mechanisms since this peptide is involved in energy homeostasis and modulates mesolimbic dopaminergic transmission. The purpose of the present study was to test this hypothesis by investigating the impact of FR on amphetamine reward in wild-type (WT) and knockout mice lacking the melanin-concentrating hormone receptor-1 (MCHR1-KO). The rewarding effects of amphetamine (0.75-2.25 mg/kg, i.p.) were measured with the conditioned place preference (CPP) technique. The food of the mice was restricted to maintain their body weight at 80-85% of their free-feeding (FF) weight throughout the entire CPP experiment. Locomotor activity of the animals was recorded during the conditioning sessions. Our results show that locomotion of all the food-restricted mice treated with saline or amphetamine increased over the sessions whatever the genotype. On the place preference test, the amplitude of CPP induced by 0.75 mg/kg amphetamine was higher in food restricted WT mice than in free-fed WT mice and food restricted MCHR1-KO mice. However, FR did not affect amphetamine reward in MCHR1-KO mice. The present results indicate that MCH signaling could be involved in the ability of FR to increase amphetamine-induced CPP.
Collapse
|