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Lee J, Gonzalez-Hernandez AJ, Kristt M, Abreu N, Roßmann K, Arefin A, Marx DC, Broichhagen J, Levitz J. Distinct beta-arrestin coupling and intracellular trafficking of metabotropic glutamate receptor homo- and heterodimers. SCIENCE ADVANCES 2023; 9:eadi8076. [PMID: 38055809 PMCID: PMC10699790 DOI: 10.1126/sciadv.adi8076] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/18/2023] [Accepted: 11/03/2023] [Indexed: 12/08/2023]
Abstract
The metabotropic glutamate receptors (mGluRs) are family C, dimeric G protein-coupled receptors (GPCRs), which play critical roles in synaptic transmission. Despite an increasing appreciation of the molecular diversity of this family, how distinct mGluR subtypes are regulated remains poorly understood. We reveal that different group II/III mGluR subtypes show markedly different beta-arrestin (β-arr) coupling and endocytic trafficking. While mGluR2 is resistant to internalization and mGluR3 shows transient β-arr coupling, which enables endocytosis and recycling, mGluR8 and β-arr form stable complexes, which leads to efficient lysosomal targeting and degradation. Using chimeras and mutagenesis, we pinpoint carboxyl-terminal domain regions that control β-arr coupling and trafficking, including the identification of an mGluR8 splice variant with impaired internalization. We then use a battery of high-resolution fluorescence assays to find that heterodimerization further expands the diversity of mGluR regulation. Together, this work provides insight into the relationship between GPCR/β-arr complex formation and trafficking while revealing diversity and intricacy in the regulation of mGluRs.
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Affiliation(s)
- Joon Lee
- Department of Biochemistry, Weill Cornell Medicine, New York, NY 10065, USA
| | | | - Melanie Kristt
- Department of Biochemistry, Weill Cornell Medicine, New York, NY 10065, USA
| | - Nohely Abreu
- Department of Biochemistry, Weill Cornell Medicine, New York, NY 10065, USA
| | - Kilian Roßmann
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie, 13125 Berlin, Germany
| | - Anisul Arefin
- Department of Biochemistry, Weill Cornell Medicine, New York, NY 10065, USA
| | - Dagan C. Marx
- Department of Biochemistry, Weill Cornell Medicine, New York, NY 10065, USA
| | | | - Joshua Levitz
- Department of Biochemistry, Weill Cornell Medicine, New York, NY 10065, USA
- Department of Psychiatry, Weill Cornell Medicine, New York, NY 10065, USA
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2
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Hochbaum DR, Dubinsky AC, Farnsworth HC, Hulshof L, Kleinberg G, Urke A, Wang W, Hakim R, Robertson K, Park C, Solberg A, Yang Y, Baynard C, Nadaf NM, Beron CC, Girasole AE, Chantranupong L, Cortopassi M, Prouty S, Geistlinger L, Banks A, Scanlan T, Greenberg ME, Boulting GL, Macosko EZ, Sabatini BL. Thyroid hormone rewires cortical circuits to coordinate body-wide metabolism and exploratory drive. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.08.10.552874. [PMID: 37609206 PMCID: PMC10441422 DOI: 10.1101/2023.08.10.552874] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/24/2023]
Abstract
Animals adapt to varying environmental conditions by modifying the function of their internal organs, including the brain. To be adaptive, alterations in behavior must be coordinated with the functional state of organs throughout the body. Here we find that thyroid hormone- a prominent regulator of metabolism in many peripheral organs- activates cell-type specific transcriptional programs in anterior regions of cortex of adult mice via direct activation of thyroid hormone receptors. These programs are enriched for axon-guidance genes in glutamatergic projection neurons, synaptic regulators across both astrocytes and neurons, and pro-myelination factors in oligodendrocytes, suggesting widespread remodeling of cortical circuits. Indeed, whole-cell electrophysiology recordings revealed that thyroid hormone induces local transcriptional programs that rewire cortical neural circuits via pre-synaptic mechanisms, resulting in increased excitatory drive with a concomitant sensitization of recruited inhibition. We find that thyroid hormone bidirectionally regulates innate exploratory behaviors and that the transcriptionally mediated circuit changes in anterior cortex causally promote exploratory decision-making. Thus, thyroid hormone acts directly on adult cerebral cortex to coordinate exploratory behaviors with whole-body metabolic state.
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3
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Mao LM, Mathur N, Shah K, Wang JQ. Roles of metabotropic glutamate receptor 8 in neuropsychiatric and neurological disorders. INTERNATIONAL REVIEW OF NEUROBIOLOGY 2023; 168:349-366. [PMID: 36868634 PMCID: PMC10162486 DOI: 10.1016/bs.irn.2022.10.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Metabotropic glutamate (mGlu) receptors are G protein-coupled receptors. Among eight mGlu subtypes (mGlu1-8), mGlu8 has drawn increasing attention. This subtype is localized to the presynaptic active zone of neurotransmitter release and is among the mGlu subtypes with high affinity for glutamate. As a Gi/o-coupled autoreceptor, mGlu8 inhibits glutamate release to maintain homeostasis of glutamatergic transmission. mGlu8 receptors are expressed in limbic brain regions and play a pivotal role in modulating motivation, emotion, cognition, and motor functions. Emerging evidence emphasizes the increasing clinical relevance of abnormal mGlu8 activity. Studies using mGlu8 selective agents and knockout mice have revealed the linkage of mGlu8 receptors to multiple neuropsychiatric and neurological disorders, including anxiety, epilepsy, Parkinson's disease, drug addiction, and chronic pain. Expression and function of mGlu8 receptors in some limbic structures undergo long-lasting adaptive changes in animal models of these disorders, which may contribute to the remodeling of glutamatergic transmission critical for the pathogenesis and symptomatology of brain illnesses. This review summarizes the current understanding of mGlu8 biology and the possible involvement of the receptor in several common psychiatric and neurological disorders.
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Affiliation(s)
- Li-Min Mao
- Department of Biomedical Sciences, University of Missouri-Kansas City, School of Medicine, Kansas City, MO, United States
| | - Nirav Mathur
- Department of Anesthesiology, University of Missouri-Kansas City, School of Medicine, Kansas City, MO, United States
| | - Karina Shah
- Department of Biomedical Sciences, University of Missouri-Kansas City, School of Medicine, Kansas City, MO, United States
| | - John Q Wang
- Department of Biomedical Sciences, University of Missouri-Kansas City, School of Medicine, Kansas City, MO, United States; Department of Anesthesiology, University of Missouri-Kansas City, School of Medicine, Kansas City, MO, United States.
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4
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Frank D, Gruenbaum BF, Zlotnik A, Semyonov M, Frenkel A, Boyko M. Pathophysiology and Current Drug Treatments for Post-Stroke Depression: A Review. Int J Mol Sci 2022; 23:ijms232315114. [PMID: 36499434 PMCID: PMC9738261 DOI: 10.3390/ijms232315114] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2022] [Revised: 11/21/2022] [Accepted: 11/26/2022] [Indexed: 12/03/2022] Open
Abstract
Post-stroke depression (PSD) is a biopsychosocial disorder that affects individuals who have suffered a stroke at any point. PSD has a 20 to 60 percent reported prevalence among stroke survivors. Its effects are usually adverse, can lead to disability, and may increase mortality if not managed or treated early. PSD is linked to several other medical conditions, including anxiety, hyper-locomotor activity, and poor functional recovery. Despite significant awareness of its adverse impacts, understanding the pathogenesis of PSD has proved challenging. The exact pathophysiology of PSD is unknown, yet its complexity has been definitively shown, involving mechanisms such as dysfunction of monoamine, the glutamatergic systems, the gut-brain axis, and neuroinflammation. The current effectiveness of PSD treatment is about 30-40 percent of all cases. In this review, we examined different pathophysiological mechanisms and current pharmacological and non-pharmacological approaches for the treatment of PSD.
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Affiliation(s)
- Dmitry Frank
- Department of Anesthesiology and Critical Care, Soroka University Medical Center, Ben-Gurion of the Negev, Beer-Sheva 84105, Israel
- Correspondence: or
| | - Benjamin F. Gruenbaum
- Department of Anesthesiology and Perioperative Medicine, Mayo Clinic, Jacksonville, FL 32224, USA
| | - Alexander Zlotnik
- Department of Anesthesiology and Critical Care, Soroka University Medical Center, Ben-Gurion of the Negev, Beer-Sheva 84105, Israel
| | - Michael Semyonov
- Department of Anesthesiology and Critical Care, Soroka University Medical Center, Ben-Gurion of the Negev, Beer-Sheva 84105, Israel
| | - Amit Frenkel
- Department of Anesthesiology and Critical Care, Soroka University Medical Center, Ben-Gurion of the Negev, Beer-Sheva 84105, Israel
| | - Matthew Boyko
- Department of Anesthesiology and Critical Care, Soroka University Medical Center, Ben-Gurion of the Negev, Beer-Sheva 84105, Israel
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5
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Targeting metabotropic glutamate receptors for the treatment of depression and other stress-related disorders. Neuropharmacology 2021; 196:108687. [PMID: 34175327 DOI: 10.1016/j.neuropharm.2021.108687] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2021] [Revised: 06/11/2021] [Accepted: 06/18/2021] [Indexed: 12/15/2022]
Abstract
The discovery of robust antidepressant effects of ketamine in refractory patients has led to increasing focus on agents targeting glutamatergic signaling as potential novel antidepressant strategy. Among the agents targeting the glutamatergic system, compounds acting at metabotropic glutamate (mGlu) receptors are among the most promising agents under studies for depressive disorders. Further, the receptor diversity, distinct distribution in the CNS, and ability to modulate the glutamatergic neurotransmission in the brain areas implicated in mood disorders make them an exciting target for stress-related disorders. In preclinical models, antidepressant and anxiolytic effects of mGlu5 negative allosteric modulators (NAMs) have been reported. Interestingly, mGlu2/3 receptor antagonists show fast and sustained antidepressant-like effects similar to that of ketamine in rodents. Excitingly, they can also induce antidepressant effects in the animal models of treatment-resistant depression and are devoid of the side-effects associated with ketamine. Unfortunately, clinical trials of both mGlu5 and mGlu2/3 receptor NAMs have been inconclusive, and additional trials using other compounds with suitable preclinical and clinical properties are needed. Although group III mGlu receptors have gained less attention, mGlu7 receptor ligands have been shown to induce antidepressant-like effects in rodents. Collectively, compounds targeting mGlu receptors provide an alternative approach to fill the outstanding clinical need for safer and more efficacious antidepressants. This article is part of the special Issue on "Glutamate Receptors - mGluRs".
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Woo MS, Ufer F, Rothammer N, Di Liberto G, Binkle L, Haferkamp U, Sonner JK, Engler JB, Hornig S, Bauer S, Wagner I, Egervari K, Raber J, Duvoisin RM, Pless O, Merkler D, Friese MA. Neuronal metabotropic glutamate receptor 8 protects against neurodegeneration in CNS inflammation. J Exp Med 2021; 218:e20201290. [PMID: 33661276 PMCID: PMC7938362 DOI: 10.1084/jem.20201290] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2020] [Revised: 12/17/2020] [Accepted: 02/02/2021] [Indexed: 12/13/2022] Open
Abstract
Multiple sclerosis (MS) is a chronic inflammatory disease of the central nervous system with continuous neuronal loss. Treatment of clinical progression remains challenging due to lack of insights into inflammation-induced neurodegenerative pathways. Here, we show that an imbalance in the neuronal receptor interactome is driving glutamate excitotoxicity in neurons of MS patients and identify the MS risk-associated metabotropic glutamate receptor 8 (GRM8) as a decisive modulator. Mechanistically, GRM8 activation counteracted neuronal cAMP accumulation, thereby directly desensitizing the inositol 1,4,5-trisphosphate receptor (IP3R). This profoundly limited glutamate-induced calcium release from the endoplasmic reticulum and subsequent cell death. Notably, we found Grm8-deficient neurons to be more prone to glutamate excitotoxicity, whereas pharmacological activation of GRM8 augmented neuroprotection in mouse and human neurons as well as in a preclinical mouse model of MS. Thus, we demonstrate that GRM8 conveys neuronal resilience to CNS inflammation and is a promising neuroprotective target with broad therapeutic implications.
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Affiliation(s)
- Marcel S. Woo
- Institut für Neuroimmunologie und Multiple Sklerose, Zentrum für Molekulare Neurobiologie Hamburg, Universitätsklinikum Hamburg-Eppendorf, Hamburg, Germany
| | - Friederike Ufer
- Institut für Neuroimmunologie und Multiple Sklerose, Zentrum für Molekulare Neurobiologie Hamburg, Universitätsklinikum Hamburg-Eppendorf, Hamburg, Germany
| | - Nicola Rothammer
- Institut für Neuroimmunologie und Multiple Sklerose, Zentrum für Molekulare Neurobiologie Hamburg, Universitätsklinikum Hamburg-Eppendorf, Hamburg, Germany
| | - Giovanni Di Liberto
- Division of Clinical Pathology, Department of Pathology and Immunology, Geneva Faculty of Medicine, Geneva, Switzerland
| | - Lars Binkle
- Institut für Neuroimmunologie und Multiple Sklerose, Zentrum für Molekulare Neurobiologie Hamburg, Universitätsklinikum Hamburg-Eppendorf, Hamburg, Germany
| | - Undine Haferkamp
- Fraunhofer Institute for Translational Medicine and Pharmacology, Hamburg, Germany
| | - Jana K. Sonner
- Institut für Neuroimmunologie und Multiple Sklerose, Zentrum für Molekulare Neurobiologie Hamburg, Universitätsklinikum Hamburg-Eppendorf, Hamburg, Germany
| | - Jan Broder Engler
- Institut für Neuroimmunologie und Multiple Sklerose, Zentrum für Molekulare Neurobiologie Hamburg, Universitätsklinikum Hamburg-Eppendorf, Hamburg, Germany
| | - Sönke Hornig
- Experimentelle Neuropädiatrie, Klinik für Kinder und Jugendmedizin, Universitätsklinikum Hamburg-Eppendorf, Hamburg, Germany
| | - Simone Bauer
- Institut für Neuroimmunologie und Multiple Sklerose, Zentrum für Molekulare Neurobiologie Hamburg, Universitätsklinikum Hamburg-Eppendorf, Hamburg, Germany
| | - Ingrid Wagner
- Division of Clinical Pathology, Department of Pathology and Immunology, Geneva Faculty of Medicine, Geneva, Switzerland
| | - Kristof Egervari
- Division of Clinical Pathology, Department of Pathology and Immunology, Geneva Faculty of Medicine, Geneva, Switzerland
| | - Jacob Raber
- Department of Behavioral Neuroscience, Oregon Health & Science University, Portland, OR
- Department of Neurology, Oregon Health & Science University, Portland, OR
- Department of Radiation Medicine, Oregon Health & Science University, Portland, OR
- Division of Neuroscience, Oregon National Primate Research Center, Oregon Health & Science University, Portland, OR
| | - Robert M. Duvoisin
- Department of Chemical Physiology and Biochemistry, Oregon Health & Science University, Portland, OR
| | - Ole Pless
- Fraunhofer Institute for Translational Medicine and Pharmacology, Hamburg, Germany
| | - Doron Merkler
- Division of Clinical Pathology, Department of Pathology and Immunology, Geneva Faculty of Medicine, Geneva, Switzerland
| | - Manuel A. Friese
- Institut für Neuroimmunologie und Multiple Sklerose, Zentrum für Molekulare Neurobiologie Hamburg, Universitätsklinikum Hamburg-Eppendorf, Hamburg, Germany
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7
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Terenina EE, Cavigelli S, Mormede P, Zhao W, Parks C, Lu L, Jones BC, Mulligan MK. Genetic Factors Mediate the Impact of Chronic Stress and Subsequent Response to Novel Acute Stress. Front Neurosci 2019; 13:438. [PMID: 31164799 PMCID: PMC6536627 DOI: 10.3389/fnins.2019.00438] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2019] [Accepted: 04/16/2019] [Indexed: 12/31/2022] Open
Abstract
Individual differences in physiological and biobehavioral adaptation to chronic stress are important predictors of health and fitness; genetic differences play an important role in this adaptation. To identify these differences we measured the biometric, neuroendocrine, and transcriptional response to stress among inbred mouse strains with varying degrees of genetic similarity, C57BL/6J (B), C57BL/6NJ (N), and DBA/2J (D). The B and D strains are highly genetically diverse whereas the B and N substrains are highly similar. Strain differences in hypothalamic-pituitary-adrenal (HPA) axis cross-sensitization were determined by plasma corticosterone (CORT) levels and hippocampal gene expression following 7-weeks of chronic mild stress (CMS) or normal housing (NH) and subsequent exposure to novel acute restraint. Fecal CORT metabolites and body and organ weights were also measured. All strains exposed to CMS had reduced heart weights, whereas body weight gain was attenuated only in B and N strains. Acute stress alone produced larger plasma CORT responses in the D and N strains compared to the B strain. CMS paired with acute stress produced cross-sensitization of the CORT response in the N strain. The N strain also had the largest number of hippocampal transcripts with up-regulated expression in response to stress. In contrast, the D strain had the largest number of transcripts with down-regulated expression following CMS and acute stress. In summary, we observed differential responses to CMS at both the physiological and molecular level among genetically diverse strains, indicating that genetic factors drive individual differences in experience-dependent regulation of the stress response.
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Affiliation(s)
- Elena E Terenina
- GenPhySE, ENVT, INRA, Université de Toulouse, Castanet-Tolosan, France.,Department of Genetics, Genomics and Informatics, University of Tennessee Health Science Center, Memphis, TN, United States
| | - Sonia Cavigelli
- Department of Biobehavioral Health, Pennsylvania State University, University Park, PA, United States
| | - Pierre Mormede
- GenPhySE, ENVT, INRA, Université de Toulouse, Castanet-Tolosan, France.,Department of Genetics, Genomics and Informatics, University of Tennessee Health Science Center, Memphis, TN, United States
| | - Wenyuan Zhao
- Department of Genetics, Genomics and Informatics, University of Tennessee Health Science Center, Memphis, TN, United States
| | - Cory Parks
- Department of Genetics, Genomics and Informatics, University of Tennessee Health Science Center, Memphis, TN, United States
| | - Lu Lu
- Department of Genetics, Genomics and Informatics, University of Tennessee Health Science Center, Memphis, TN, United States
| | - Byron C Jones
- Department of Genetics, Genomics and Informatics, University of Tennessee Health Science Center, Memphis, TN, United States
| | - Megan K Mulligan
- Department of Genetics, Genomics and Informatics, University of Tennessee Health Science Center, Memphis, TN, United States
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8
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Joffe ME, Centanni SW, Jaramillo AA, Winder DG, Conn PJ. Metabotropic Glutamate Receptors in Alcohol Use Disorder: Physiology, Plasticity, and Promising Pharmacotherapies. ACS Chem Neurosci 2018; 9:2188-2204. [PMID: 29792024 PMCID: PMC6192262 DOI: 10.1021/acschemneuro.8b00200] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Developing efficacious treatments for alcohol use disorder (AUD) has proven difficult. The insidious nature of the disease necessitates a deep understanding of its underlying biology as well as innovative approaches to ameliorate ethanol-related pathophysiology. Excessive ethanol seeking and relapse are generated by long-term changes to membrane properties, synaptic physiology, and plasticity throughout the limbic system and associated brain structures. Each of these factors can be modulated by metabotropic glutamate (mGlu) receptors, a diverse set of G protein-coupled receptors highly expressed throughout the central nervous system. Here, we discuss how different components of the mGlu receptor family modulate neurotransmission in the limbic system and other brain regions involved in AUD etiology. We then describe how these processes are dysregulated following ethanol exposure and speculate about how mGlu receptor modulation might restore such pathophysiological changes. To that end, we detail the current understanding of the behavioral pharmacology of mGlu receptor-directed drug-like molecules in animal models of AUD. Together, this review highlights the prominent position of the mGlu receptor system in the pathophysiology of AUD and provides encouragement that several classes of mGlu receptor modulators may be translated as viable treatment options.
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Affiliation(s)
- Max E. Joffe
- Department of Pharmacology, Vanderbilt University, Nashville, Tennessee 37232-0697, United States
- Vanderbilt Center for Neuroscience Drug Discovery, Vanderbilt University, Nashville, Tennessee 37232-0697, United States
- Vanderbilt Center for Addiction Research, Vanderbilt University, Nashville, Tennessee 37232-0697, United States
| | - Samuel W. Centanni
- Vanderbilt Center for Addiction Research, Vanderbilt University, Nashville, Tennessee 37232-0697, United States
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, Tennessee 37212, United States
| | - Anel A. Jaramillo
- Vanderbilt Center for Addiction Research, Vanderbilt University, Nashville, Tennessee 37232-0697, United States
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, Tennessee 37212, United States
| | - Danny G. Winder
- Department of Pharmacology, Vanderbilt University, Nashville, Tennessee 37232-0697, United States
- Vanderbilt Center for Addiction Research, Vanderbilt University, Nashville, Tennessee 37232-0697, United States
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, Tennessee 37212, United States
| | - P. Jeffrey Conn
- Department of Pharmacology, Vanderbilt University, Nashville, Tennessee 37232-0697, United States
- Vanderbilt Center for Neuroscience Drug Discovery, Vanderbilt University, Nashville, Tennessee 37232-0697, United States
- Vanderbilt Center for Addiction Research, Vanderbilt University, Nashville, Tennessee 37232-0697, United States
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9
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Lian YN, Lu Q, Chang JL, Zhang Y. The role of glutamate and its receptors in central nervous system in stress-induced hyperalgesia. Int J Neurosci 2017; 128:283-290. [DOI: 10.1080/00207454.2017.1387112] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Affiliation(s)
- Yan-Na Lian
- Department of Physiology, Harbin Medical University, Harbin, P. R. China
| | - Qi Lu
- Department of Physiology, Harbin Medical University, Harbin, P. R. China
| | - Jin-Long Chang
- Department of Physiology, Harbin Medical University, Harbin, P. R. China
| | - Ying Zhang
- Department of Physiology, Harbin Medical University, Harbin, P. R. China
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10
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Maksymetz J, Moran SP, Conn PJ. Targeting metabotropic glutamate receptors for novel treatments of schizophrenia. Mol Brain 2017; 10:15. [PMID: 28446243 PMCID: PMC5405554 DOI: 10.1186/s13041-017-0293-z] [Citation(s) in RCA: 95] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2016] [Accepted: 04/04/2017] [Indexed: 12/22/2022] Open
Abstract
Support for the N-methyl-D-aspartate receptor (NMDAR) hypofunction hypothesis of schizophrenia has led to increasing focus on restoring proper glutamatergic signaling as an approach for treatment of this devastating disease. The ability of metabotropic glutamate (mGlu) receptors to modulate glutamatergic neurotransmission has thus attracted considerable attention for the development of novel antipsychotics. Consisting of eight subtypes classified into three groups based on sequence homology, signal transduction, and pharmacology, the mGlu receptors provide a wide range of targets to modulate NMDAR function as well as glutamate release. Recently, allosteric modulators of mGlu receptors have been developed that allow unprecedented selectivity among subtypes, not just groups, facilitating the investigation of the effects of subtype-specific modulation. In preclinical animal models, positive allosteric modulators (PAMs) of the group I mGlu receptor mGlu5 have efficacy across all three symptom domains of schizophrenia (positive, negative, and cognitive). The discovery and development of mGlu5 PAMs that display unique signal bias suggests that efficacy can be retained while avoiding the neurotoxic effects of earlier compounds. Interestingly, mGlu1 negative allosteric modulators (NAMs) appear efficacious in positive symptom models of the disease but are still in early preclinical development. While selective group II mGlu receptor (mGlu2/3) agonists have reached clinical trials but were unsuccessful, specific mGlu2 or mGlu3 receptor targeting still hold great promise. Genetic studies implicated mGlu2 in the antipsychotic effects of group II agonists and mGlu2 PAMs have since entered into clinical trials. Additionally, mGlu3 appears to play an important role in cognition, may confer neuroprotective effects, and thus is a promising target to alleviate cognitive deficits in schizophrenia. Although group III mGlu receptors (mGlu4/6/7/8) have attracted less attention, mGlu4 agonists and PAMs appear to have efficacy across all three symptoms domains in preclinical models. The recent discovery of heterodimers comprising mGlu2 and mGlu4 may explain the efficacy of mGlu4 selective compounds but this remains to be determined. Taken together, compounds targeting mGlu receptors, specifically subtype-selective allosteric modulators, provide a compelling alternative approach to fill the unmet clinical needs for patients with schizophrenia.
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Affiliation(s)
- James Maksymetz
- Department of Pharmacology, Vanderbilt University, Nashville, TN 37232 USA
- Vanderbilt Center for Neuroscience Drug Discovery, Nashville, TN 37232 USA
| | - Sean P. Moran
- Vanderbilt Center for Neuroscience Drug Discovery, Nashville, TN 37232 USA
- Vanderbilt Brain Institute, Vanderbilt University, Nashville, TN 37232 USA
| | - P. Jeffrey Conn
- Department of Pharmacology, Vanderbilt University, Nashville, TN 37232 USA
- Vanderbilt Center for Neuroscience Drug Discovery, Nashville, TN 37232 USA
- Vanderbilt Brain Institute, Vanderbilt University, Nashville, TN 37232 USA
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11
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12
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Zhou WJ, Xu N, Kong L, Sun SC, Xu XF, Jia MZ, Wang Y, Chen ZY. The antidepressant roles of Wnt2 and Wnt3 in stress-induced depression-like behaviors. Transl Psychiatry 2016; 6:e892. [PMID: 27622936 PMCID: PMC5048193 DOI: 10.1038/tp.2016.122] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/14/2016] [Revised: 04/23/2016] [Accepted: 05/09/2016] [Indexed: 12/14/2022] Open
Abstract
Wnts-related signaling pathways have been reported to play roles in the pathogenesis of stress-induced depression-like behaviors. However, there is relatively few direct evidence to indicate the effect of Wnt ligands on this process. Here, we investigated the role of Wnts in mediating chronic restraint stress (CRS)-induced depression-like behaviors. We found that CRS induced a significant decrease in the expression of Wnt2 and Wnt3 in the ventral hippocampus (VH) but not in the dorsal hippocampus. Knocking down Wnt2 or Wnt3 in the VH led to impaired Wnt/β-catenin signaling, neurogenesis deficits and depression-like behaviors. In contrast, overexpression of Wnt2 or Wnt3 reversed CRS-induced depression-like behaviors. Moreover, Wnt2 and Wnt3 activated cAMP response element-binding protein (CREB) and there was CREB-dependent positive feedback between Wnt2 and Wnt3. Finally, fluoxetine treatment increased Wnt2 and Wnt3 levels in the VH and knocking down Wnt2 or Wnt3 abolished the antidepressant effect of fluoxetine. Taken together, our study indicates essential roles for Wnt2 and Wnt3 in CRS-induced depression-like behaviors and antidepressant.
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Affiliation(s)
- W-J Zhou
- Department of Neurobiology, Shandong Provincial Key Laboratory of Mental Disorders, CAS Center for Excellence in Brain Science and Intelligence Technology, School of Medicine, Shandong University, Jinan, Shandong, China
| | - N Xu
- Department of Neurobiology, Shandong Provincial Key Laboratory of Mental Disorders, CAS Center for Excellence in Brain Science and Intelligence Technology, School of Medicine, Shandong University, Jinan, Shandong, China
- Department of Clinical Laboratory, Second Hospital of Shandong University, Jinan, Shandong, China
| | - L Kong
- Department of Neurobiology, Shandong Provincial Key Laboratory of Mental Disorders, CAS Center for Excellence in Brain Science and Intelligence Technology, School of Medicine, Shandong University, Jinan, Shandong, China
| | - S-C Sun
- Department of Neurobiology, Shandong Provincial Key Laboratory of Mental Disorders, CAS Center for Excellence in Brain Science and Intelligence Technology, School of Medicine, Shandong University, Jinan, Shandong, China
| | - X-F Xu
- Department of Neurobiology, Shandong Provincial Key Laboratory of Mental Disorders, CAS Center for Excellence in Brain Science and Intelligence Technology, School of Medicine, Shandong University, Jinan, Shandong, China
| | - M-Z Jia
- Department of Neurobiology, Shandong Provincial Key Laboratory of Mental Disorders, CAS Center for Excellence in Brain Science and Intelligence Technology, School of Medicine, Shandong University, Jinan, Shandong, China
| | - Y Wang
- Department of Neurobiology, Shandong Provincial Key Laboratory of Mental Disorders, CAS Center for Excellence in Brain Science and Intelligence Technology, School of Medicine, Shandong University, Jinan, Shandong, China
| | - Z-Y Chen
- Department of Neurobiology, Shandong Provincial Key Laboratory of Mental Disorders, CAS Center for Excellence in Brain Science and Intelligence Technology, School of Medicine, Shandong University, Jinan, Shandong, China
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13
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Govea RM, Zhou S, Carlton SM. Group III mGluR8 negatively modulates TRPA1. Neuroscience 2016; 334:134-147. [PMID: 27497709 DOI: 10.1016/j.neuroscience.2016.07.047] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2016] [Revised: 07/28/2016] [Accepted: 07/29/2016] [Indexed: 01/01/2023]
Abstract
Several lines of evidence indicate group III metabotropic glutamate receptors (mGluRs) have systemic anti-hyperalgesic effects. We hypothesized this could occur through modulation of TRP channels on nociceptors. This study used a multifaceted approach to examine the interaction between group III mGluRs (mGluR8) and transient receptor potential ankyrin 1 (TRPA1) on cutaneous nociceptors in rats. Ca2+ imaging studies demonstrated co-localization and functional coupling of TRPA1 and mGluR8, since 1μM (S)-3,4-dicarboxyphenylglycine (DCPG) (mGluR8 agonist) significantly reduced Ca2+ mobilization produced by 30μM mustard oil (MO), a TRPA1 agonist. Behavioral studies demonstrated that 10mM MO produced mechanical hypersensitivity when topically applied to the hind paw, significantly decreasing paw withdrawal threshold (PWT) from 15g to 6g. However, administration of 30μM DCPG prior to 10mM MO reversed this hypersensitivity such that PWT was not significantly different from baseline. At the single-fiber level, compared to vehicle, 30μM MO significantly increased nociceptor activity and decreased mechanical threshold. However, 30μM DCPG reversed both of these MO-induced effects. Furthermore, DCPG significantly reduced the number of MO-induced mechanically sensitive fibers. Inhibition of protein kinase A (PKA) using Rp-cyclic 3',5'-hydrogen phosphorothioate adenosine triethylammonium salt (RpCAMPS) (PKA inhibitor, 1 and 10μM) significantly reduced MO-induced Ca2+ mobilization. Taken together, these results show that group III mGluRs negatively modulate TRPA1 activity on cutaneous nociceptors. Furthermore, it is likely that this modulation occurs intracellularly at the level of the cAMP/PKA pathway. This study demonstrates that group III agonists may be effective in the treatment of mechanical hypersensitivity which can develop as a result of inflammation, nerve injury, chemotherapy and other disease states.
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Affiliation(s)
- R M Govea
- Department of Neuroscience and Cell Biology, University of Texas Medical Branch, Galveston, TX 77555-1069, United States
| | - S Zhou
- Department of Neuroscience and Cell Biology, University of Texas Medical Branch, Galveston, TX 77555-1069, United States
| | - S M Carlton
- Department of Neuroscience and Cell Biology, University of Texas Medical Branch, Galveston, TX 77555-1069, United States.
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Afshari P, Myles-Worsley M, Cohen OS, Tiobech J, Faraone SV, Byerley W, Middleton FA. Characterization of a Novel Mutation in SLC1A1 Associated with Schizophrenia. MOLECULAR NEUROPSYCHIATRY 2015; 1:125-44. [PMID: 26380821 DOI: 10.1159/000433599] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/20/2015] [Accepted: 05/20/2015] [Indexed: 01/25/2023]
Abstract
We have recently described a hemi-deletion on chromosome 9p24.2 at the SLC1A1 gene locus and its co-segregation with schizophrenia in an extended Palauan pedigree. This finding represents a point of convergence for several pathophysiological models of schizophrenia. The present report sought to characterize the biological consequences of this hemi-deletion. Dual luciferase assays demonstrated that the partially deleted allele (lacking exon 1 and the native promoter) can drive expression of a 5'-truncated SLC1A1 using sequence upstream of exon 2 as a surrogate promoter. However, confocal microscopy and electrophysiological recordings demonstrate that the 5'-truncated SLC1A1 lacks normal membrane localization and glutamate transport ability. To identify downstream consequences of the hemi-deletion, we first used a themed qRT-PCR array to compare expression of 84 GABA and glutamate genes in RNA from peripheral blood leukocytes in deletion carriers (n = 11) versus noncarriers (n = 8) as well as deletion carriers with psychosis (n = 5) versus those without (n = 3). Then, targeted RNA-Seq (TREx) was used to quantify expression of 375 genes associated with neuropsychiatric disorders in HEK293 cells subjected to either knockdown of SLC1A1 or overexpression of full-length or 5'-truncated SLC1A1. Expression changes of several genes strongly implicated in schizophrenia pathophysiology were detected (e.g. SLC1A2, SLC1A3, SLC1A6, SLC7A11, GRIN2A, GRIA1 and DLX1).
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Affiliation(s)
- Parisa Afshari
- Departments of Neuroscience and Physiology, SUNY Upstate Medical University, Syracuse, N.Y., USA
| | - Marina Myles-Worsley
- Departments of Psychiatry and Behavioral Sciences, SUNY Upstate Medical University, Syracuse, N.Y., USA
| | - Ori S Cohen
- Departments of Psychiatry and Behavioral Sciences, SUNY Upstate Medical University, Syracuse, N.Y., USA
| | | | - Stephen V Faraone
- Departments of Neuroscience and Physiology, SUNY Upstate Medical University, Syracuse, N.Y., USA; Departments of Psychiatry and Behavioral Sciences, SUNY Upstate Medical University, Syracuse, N.Y., USA
| | - William Byerley
- Department of Psychiatry, University of California at San Francisco, San Francisco, Calif., USA
| | - Frank A Middleton
- Departments of Neuroscience and Physiology, SUNY Upstate Medical University, Syracuse, N.Y., USA; Departments of Psychiatry and Behavioral Sciences, SUNY Upstate Medical University, Syracuse, N.Y., USA; Departments of Biochemistry and Molecular Biology, SUNY Upstate Medical University, Syracuse, N.Y., USA
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15
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Raber J, Duvoisin RM. Novel metabotropic glutamate receptor 4 and glutamate receptor 8 therapeutics for the treatment of anxiety. Expert Opin Investig Drugs 2014; 24:519-28. [DOI: 10.1517/13543784.2014.986264] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Affiliation(s)
- Jacob Raber
- 1Departments of Behavioral Neuroscience, Neurology, and Radiation Medicine, Oregon Health and Science University, Division of Neuroscience, ONPRC, Portland, OR, USA ;
| | - Robert M Duvoisin
- 2Department of Physiology and Pharmacology, Oregon Health and Science University, Portland, OR, USA
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16
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Mercier MS, Lodge D. Group III metabotropic glutamate receptors: pharmacology, physiology and therapeutic potential. Neurochem Res 2014; 39:1876-94. [PMID: 25146900 DOI: 10.1007/s11064-014-1415-y] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2014] [Revised: 08/08/2014] [Accepted: 08/11/2014] [Indexed: 01/14/2023]
Abstract
Glutamate, the primary excitatory neurotransmitter in the central nervous system (CNS), exerts neuromodulatory actions via the activation of metabotropic glutamate (mGlu) receptors. There are eight known mGlu receptor subtypes (mGlu1-8), which are widely expressed throughout the brain, and are divided into three groups (I-III), based on signalling pathways and pharmacological profiles. Group III mGlu receptors (mGlu4/6/7/8) are primarily, although not exclusively, localised on presynaptic terminals, where they act as both auto- and hetero-receptors, inhibiting the release of neurotransmitter. Until recently, our understanding of the role of individual group III mGlu receptor subtypes was hindered by a lack of subtype-selective pharmacological tools. Recent advances in the development of both orthosteric and allosteric group III-targeting compounds, however, have prompted detailed investigations into the possible functional role of these receptors within the CNS, and revealed their involvement in a number of pathological conditions, such as epilepsy, anxiety and Parkinson's disease. The heterogeneous expression of group III mGlu receptor subtypes throughout the brain, as well as their distinct distribution at glutamatergic and GABAergic synapses, makes them ideal targets for therapeutic intervention. This review summarises the advances in subtype-selective pharmacology, and discusses the individual roles of group III mGlu receptors in physiology, and their potential involvement in disease.
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Affiliation(s)
- Marion S Mercier
- Centre for Synaptic Plasticity, School of Physiology and Pharmacology, Dorothy Hodgkin Building, University of Bristol, Bristol, BS1 3NY, UK,
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17
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The effects of stress on glutamatergic transmission in the brain. Mol Neurobiol 2014; 51:1139-43. [PMID: 24939697 DOI: 10.1007/s12035-014-8783-9] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2014] [Accepted: 06/09/2014] [Indexed: 12/26/2022]
Abstract
Stress leads to detrimental effects on brain functions and results in various diseases. Recent studies highlight the involvement of glutamatergic transmission in pathogenesis of depressive behaviors and fears. Acute stress generates different impacts on the excitatory transmission compared to chronic stress. Different neuromodulators and epigenetic factors also participate in the alteration of synaptic transmission and the regulation of synaptic plasticity. Restoration of the glutamatergic transmission in stress-affected brain areas therefore provides novel directions of therapeutic interventions against stress.
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18
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Davis MJ, Duvoisin RM, Raber J. Related functions of mGlu4 and mGlu8. Pharmacol Biochem Behav 2013; 111:11-6. [PMID: 23948069 DOI: 10.1016/j.pbb.2013.07.022] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/04/2013] [Revised: 07/25/2013] [Accepted: 07/31/2013] [Indexed: 11/15/2022]
Abstract
Metabotropic glutamate receptors modulate glutamatergic and GABAergic neurotransmission. Our previous pharmacological data indicate that metabotropic receptor 4 (mGlu4) and metabotropic receptor 8 (mGlu8) might have related and overlapping functions. We explored this by analyzing the behavioral phenotypes of mice deficient in either (mGlu4(-/-) or mGlu8(-/-)) or both receptors (mGlu4/8(-/-)). Our analysis focused on measures of anxiety in the open field and elevated zero maze, sensorimotor function on the rotarod and fear conditioning, as mGlu4 and/or mGlu8 were shown to affect performance in these tests. mGlu8(-/-) mice weighed more than mGlu4/8(-/-) mice. In the open field, mGlu4(-/-) mice showed lower levels of anxiety than mGlu8(-/-) and mGlu4/8(-/-) mice. In the elevated zero maze, mGlu4(-/-) mice showed lower levels of anxiety than wild-type, mGlu8(-/-) and mGlu4/8(-/-) mice. In the open field, but not elevated zero maze, mGlu4(-/-) mice showed lower activity levels than wild-type, mGlu8(-/-) and mGlu4/8(-/-) mice. mGlu4/8(-/-) female mice showed less contextual freezing than wild-type and mGlu4(-/-) female mice and there was a trend toward less freezing in male mGlu4/8(-/-) than wild-type male mice. There were no genotype differences in cued fear conditioning. There were significant negative correlations between body weight and fall latency on the rotarod in wild-type, mGlu8(-/-) and mGlu4/8(-/-), but not mGlu4(-/-), mice. These data suggest related functions of mGlu4 and mGlu8 in behavioral performance.
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Affiliation(s)
- Matthew J Davis
- Department of Behavioral Neuroscience, Oregon Health & Science University, Portland, OR, USA
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19
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Antagonists reversibly reverse chemical LTD induced by group I, group II and group III metabotropic glutamate receptors. Neuropharmacology 2013; 74:135-46. [PMID: 23542080 DOI: 10.1016/j.neuropharm.2013.03.011] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2012] [Revised: 02/25/2013] [Accepted: 03/07/2013] [Indexed: 11/21/2022]
Abstract
Metabotropic glutamate (mGlu) receptors are implicated in many neurological and psychiatric diseases and are the targets of therapeutic agents currently in clinical development. Their activation has diverse effects in the central nervous system (CNS) that includes an involvement in synaptic plasticity. We previously reported that the brief exposure of hippocampal slices to dihydroxyphenylglycine (DHPG) can result in a long-term depression (LTD) of excitatory synaptic transmission. Surprisingly, this LTD could be fully reversed by mGlu receptor antagonists in a manner that was itself fully reversible upon washout of the antagonist. Here, 15 years after the discovery of DHPG-LTD and its reversible reversibility, we summarise these initial findings. We then present new data on DHPG-LTD, which demonstrates that evoked epileptiform activity triggered by activation of group I mGlu receptors can also be reversibly reversed by mGlu receptor antagonists. Furthermore, we show that the phenomenon of reversible reversibility is not specific to group I mGlu receptors. We report that activation of group II mGlu receptors in the temporo-ammonic pathway (TAP) and mossy fibre pathway within the hippocampus and in the cortical input to neurons of the lateral amygdala induces an LTD that is reversed by LY341495, a group II mGlu receptor antagonist. We also show that activation of group III mGlu8 receptors induces an LTD at lateral perforant path inputs to the dentate gyrus and that this LTD is reversed by MDCPG, an mGlu8 receptor antagonist. In conclusion, we have shown that activation of representative members of each of the three groups of mGlu receptors can induce forms of LTD than can be reversed by antagonists, and that in each case washout of the antagonist is associated with the re-establishment of the LTD. This article is part of the Special Issue entitled 'Glutamate Receptor-Dependent Synaptic Plasticity'.
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20
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Turesson HK, Rodríguez-Sierra OE, Pare D. Intrinsic connections in the anterior part of the bed nucleus of the stria terminalis. J Neurophysiol 2013; 109:2438-50. [PMID: 23446692 DOI: 10.1152/jn.00004.2013] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Intrinsic connections in the anterior portion of the bed nucleus of the stria terminalis (BNST-A) were studied using patch recordings and ultraviolet (UV) glutamate uncaging (GU) in vitro. UV light was delivered at small BNST-A sites in a grid-like pattern while evoked responses were monitored in different BNST-A regions. Three sectors were distinguished in the BNST-A using fiber bundles readily identifiable in transilluminated slices: the anterior commissure, dividing the BNST-A into dorsal and ventral (BNST-AV) regions, and the intra-BNST component of the stria terminalis, subdividing the dorsal portion into medial (BNST-AM) and lateral (BNST-AL) regions. Overall, GU elicited GABAergic inhibitory postsynaptic potentials (IPSPs) more frequently than excitatory postsynaptic potentials. The incidence of intraregional connections was higher than interregional links. With respect to the latter, asymmetric connections were seen between different parts of the BNST-A. Indeed, while reciprocal connections were found between the BNST-AL and BNST-AM, BNST-AL to BNST-AM connections were more frequent than in the opposite direction. Similarly, while GU in the BNST-AM or BNST-AL often elicited IPSPs in BNST-AV cells, the opposite was rarely seen. Within the BNST-AM, connections were polarized, with dorsal GU sites eliciting IPSPs in more ventrally located cells more frequently than the opposite. This trend was not seen in other regions of the BNST. Consistent with this, most BNST-AM cells had dorsally directed dendrites and ventrally ramified axons, whereas this morphological polarization was not seen in other parts of the BNST-A. Overall, our results reveal a hitherto unsuspected level of asymmetry in the connections within and between different BNST-A regions, implying a degree of interdependence in their activity.
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Affiliation(s)
- Hjalmar K Turesson
- Center for Molecular and Behavioral Neuroscience, Rutgers State University, Newark, New Jersey 07102, USA
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21
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Conrad KL, Davis AR, Silberman Y, Sheffler DJ, Shields AD, Saleh SA, Sen N, Matthies HJG, Javitch JA, Lindsley CW, Winder DG. Yohimbine depresses excitatory transmission in BNST and impairs extinction of cocaine place preference through orexin-dependent, norepinephrine-independent processes. Neuropsychopharmacology 2012; 37:2253-66. [PMID: 22617356 PMCID: PMC3422490 DOI: 10.1038/npp.2012.76] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The alpha2 adrenergic receptor (α(2)-AR) antagonist yohimbine is a widely used tool for the study of anxiogenesis and stress-induced drug-seeking behavior. We previously demonstrated that yohimbine paradoxically depresses excitatory transmission in the bed nucleus of the stria terminalis (BNST), a region critical to the integration of stress and reward pathways, and produces an impairment of extinction of cocaine-conditioned place preference (cocaine-CPP) independent of α(2)-AR signaling. Recent studies show yohimbine-induced drug-seeking behavior is attenuated by orexin receptor 1 (OX(1)R) antagonists. Moreover, yohimbine-induced cocaine-seeking behavior is BNST-dependent. Here, we investigated yohimbine-orexin interactions. Our results demonstrate yohimbine-induced depression of excitatory transmission in the BNST is unaffected by alpha1-AR and corticotropin-releasing factor receptor-1 (CRFR(1)) antagonists, but is (1) blocked by OxR antagonists and (2) absent in brain slices from orexin knockout mice. Although the actions of yohimbine were not mimicked by the norepinephrine transporter blocker reboxetine, they were by exogenously applied orexin A. We find that, as with yohimbine, orexin A depression of excitatory transmission in BNST is OX(1)R-dependent. Finally, we find these ex vivo effects are paralleled in vivo, as yohimbine-induced impairment of cocaine-CPP extinction is blocked by a systemically administered OX(1)R antagonist. These data highlight a new mechanism for orexin on excitatory anxiety circuits and demonstrate that some of the actions of yohimbine may be directly dependent upon orexin signaling and independent of norepinephrine and CRF in the BNST.
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Affiliation(s)
- Kelly L Conrad
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, TN, USA
| | - Adeola R Davis
- Department of Center for Molecular Neuroscience, Vanderbilt University School of Medicine, Nashville, TN, USA
| | - Yuval Silberman
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, TN, USA
| | - Douglas J Sheffler
- Department of Pharmacology, Vanderbilt University School of Medicine, Nashville, TN, USA,Department of Vanderbilt Center for Neuroscience Drug Discovery, Vanderbilt University School of Medicine, Nashville, TN, USA
| | - Angela D Shields
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, TN, USA
| | - Sam A Saleh
- Department of Pharmacology, Vanderbilt University School of Medicine, Nashville, TN, USA
| | - Namita Sen
- Department of Psychiatry, College of Physicians and Surgeons, Columbia University, New York, NY, USA,Department of Pharmacology, College of Physicians and Surgeons, Columbia University, New York, NY, USA,Department of Pharmacology, Center for Molecular Recognition, College of Physicians and Surgeons, Columbia University, New York, NY, USA
| | - Heinrich JG Matthies
- Department of Center for Molecular Neuroscience, Vanderbilt University School of Medicine, Nashville, TN, USA
| | - Jonathan A Javitch
- Department of Psychiatry, College of Physicians and Surgeons, Columbia University, New York, NY, USA,Department of Pharmacology, College of Physicians and Surgeons, Columbia University, New York, NY, USA,Department of Pharmacology, Center for Molecular Recognition, College of Physicians and Surgeons, Columbia University, New York, NY, USA
| | - Craig W Lindsley
- Department of Pharmacology, Vanderbilt University School of Medicine, Nashville, TN, USA,Department of Vanderbilt Center for Neuroscience Drug Discovery, Vanderbilt University School of Medicine, Nashville, TN, USA
| | - Danny G Winder
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, TN, USA,Department of Center for Molecular Neuroscience, Vanderbilt University School of Medicine, Nashville, TN, USA,Kennedy Center for Research on Human Development, Vanderbilt University School of Medicine, Nashville, TN, USA,Vanderbilt Brain Institute, Nashville, TN, USA,Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, TN 37232, USA, Tel: +1 615 322 1144, Fax: +1 615 322 1462, E-mail:
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22
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Dobi A, Sartori SB, Busti D, Van der Putten H, Singewald N, Shigemoto R, Ferraguti F. Neural substrates for the distinct effects of presynaptic group III metabotropic glutamate receptors on extinction of contextual fear conditioning in mice. Neuropharmacology 2012; 66:274-89. [PMID: 22643400 PMCID: PMC3557389 DOI: 10.1016/j.neuropharm.2012.05.025] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2012] [Revised: 05/09/2012] [Accepted: 05/17/2012] [Indexed: 12/22/2022]
Abstract
The group III metabotropic glutamate (mGlu) receptors mGlu7 and mGlu8 are receiving increased attention as potential novel therapeutic targets for anxiety disorders. The effects mediated by these receptors appear to result from a complex interplay of facilitatory and inhibitory actions at different brain sites in the anxiety/fear circuits. To better understand the effect of mGlu7 and mGlu8 receptors on extinction of contextual fear and their critical sites of action in the fear networks, we focused on the amygdala. Direct injection into the basolateral complex of the amygdala of the mGlu7 receptor agonist AMN082 facilitated extinction, whereas the mGlu8 receptor agonist (S)-3,4-DCPG sustained freezing during the extinction acquisition trial. We also determined at the ultrastructural level the synaptic distribution of these receptors in the basal nucleus (BA) and intercalated cell clusters (ITCs) of the amygdala. Both areas are thought to exert key roles in fear extinction. We demonstrate that mGlu7 and mGlu8 receptors are located in different presynaptic terminals forming both asymmetric and symmetric synapses, and that they preferentially target neurons expressing mGlu1α receptors mostly located around ITCs. In addition we show that mGlu7 and mGlu8 receptors were segregated to different inputs to a significant extent. In particular, mGlu7a receptors were primarily onto glutamatergic afferents arising from the BA or midline thalamic nuclei, but not the medial prefrontal cortex (mPFC), as revealed by combined anterograde tracing and pre-embedding electron microscopy. On the other hand, mGlu8a showed a more restricted distribution in the BA and appeared absent from thalamic, mPFC and intrinsic inputs. This segregation of mGlu7 and mGlu8 receptors in different neuronal pathways of the fear circuit might explain the distinct effects on fear extinction training observed with mGlu7 and mGlu8 receptor agonists. This article is part of a Special Issue entitled 'Metabotropic Glutamate Receptors'.
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Affiliation(s)
- Alice Dobi
- Division of Cerebral Structure, National Institute for Physiological Sciences, Myodaiji, Okazaki 444-8787, Japan
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