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Jiang S, Su J, Yao S, Zhang Y, Cao F, Wang F, Wang H, Li J, Xi S. Fluoride and arsenic exposure impairs learning and memory and decreases mGluR5 expression in the hippocampus and cortex in rats. PLoS One 2014; 9:e96041. [PMID: 24759735 PMCID: PMC3997496 DOI: 10.1371/journal.pone.0096041] [Citation(s) in RCA: 65] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2013] [Accepted: 04/02/2014] [Indexed: 11/18/2022] Open
Abstract
Fluoride and arsenic are two common inorganic contaminants in drinking water that are associated with impairment in child development and retarded intelligence. The present study was conducted to explore the effects on spatial learning, memory, glutamate levels, and group I metabotropic glutamate receptors (mGluRs) expression in the hippocampus and cortex after subchronic exposure to fluoride, arsenic, and a fluoride and arsenic combination in rats. Weaned male Sprague-Dawley rats were assigned to four groups. The control rats drank tap water. Rats in the three exposure groups drank water with sodium fluoride (120 mg/L), sodium arsenite (70 mg/L), and a sodium fluoride (120 mg/L) and sodium arsenite (70 mg/L) combination for 3 months. Spatial learning and memory was measured in Morris water maze. mGluR1 and mGluR5 mRNA and protein expression in the hippocampus and cortex was detected using RT-PCR and Western blot, respectively. Compared with controls, learning and memory ability declined in rats that were exposed to fluoride and arsenic both alone and combined. Combined fluoride and arsenic exposure did not have a more pronounced effect on spatial learning and memory compared with arsenic and fluoride exposure alone. Compared with controls, glutamate levels decreased in the hippocampus and cortex of rats exposed to fluoride and combined fluoride and arsenic, and in cortex of arsenic-exposed rats. mGluR5 mRNA and protein expressions in the hippocampus and mGluR5 protein expression in the cortex decreased in rats exposed to arsenic alone. Interestingly, compared with fluoride and arsenic exposure alone, fluoride and arsenic combination decreased mGluR5 mRNA expression in the cortex and protein expression in the hippocampus, suggesting a synergistic effect of fluoride and arsenic. These data indicate that fluoride and arsenic, either alone or combined, can decrease learning and memory ability in rats. The mechanism may be associated with changes of glutamate level and mGluR5 expression in cortex and hippocampus.
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Affiliation(s)
- Shoufang Jiang
- Department of Occupational and Environmental Health, Liaoning Provincial Key Lab of Arsenic Biological Effect and Poisoning, School of Public Health, China Medical University, Shenyang, Liaoning, P. R. China
- Department of Occupational and Environmental Health, Hebei Province Key Laboratory of Occupational Health and Safety for Coal Industry, School of Public Health, Hebei United University, Tangshan, Hebei, P. R. China
| | - Jing Su
- Department of Occupational and Environmental Health, Hebei Province Key Laboratory of Occupational Health and Safety for Coal Industry, School of Public Health, Hebei United University, Tangshan, Hebei, P. R. China
| | - Sanqiao Yao
- Department of Occupational and Environmental Health, Hebei Province Key Laboratory of Occupational Health and Safety for Coal Industry, School of Public Health, Hebei United University, Tangshan, Hebei, P. R. China
| | - Yanshu Zhang
- Department of Occupational and Environmental Health, Hebei Province Key Laboratory of Occupational Health and Safety for Coal Industry, School of Public Health, Hebei United University, Tangshan, Hebei, P. R. China
| | - Fuyuan Cao
- Laboratory Animal Center, Hebei United University, Tangshan, Hebei, P. R. China
| | - Fei Wang
- Department of Occupational and Environmental Health, Liaoning Provincial Key Lab of Arsenic Biological Effect and Poisoning, School of Public Health, China Medical University, Shenyang, Liaoning, P. R. China
| | - Huihui Wang
- Department of Occupational and Environmental Health, Liaoning Provincial Key Lab of Arsenic Biological Effect and Poisoning, School of Public Health, China Medical University, Shenyang, Liaoning, P. R. China
| | - Jun Li
- Department of Occupational and Environmental Health, Hebei Province Key Laboratory of Occupational Health and Safety for Coal Industry, School of Public Health, Hebei United University, Tangshan, Hebei, P. R. China
| | - Shuhua Xi
- Department of Occupational and Environmental Health, Liaoning Provincial Key Lab of Arsenic Biological Effect and Poisoning, School of Public Health, China Medical University, Shenyang, Liaoning, P. R. China
- * E-mail:
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152
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Bird MK, Lohmann P, West B, Brown RM, Kirchhoff J, Raymond CR, Lawrence AJ. The mGlu5 receptor regulates extinction of cocaine-driven behaviours. Drug Alcohol Depend 2014; 137:83-9. [PMID: 24576814 DOI: 10.1016/j.drugalcdep.2014.01.017] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/30/2013] [Revised: 01/07/2014] [Accepted: 01/13/2014] [Indexed: 11/24/2022]
Abstract
BACKGROUND There is extensive evidence implicating the metabotropic glutamate 5 (mGlu5) receptor in aspects of addiction-related behaviours. METHODS Here, we used a well-characterized line of mGlu5-deficient mice to further examine the role of this receptor in cocaine-driven behaviours. We confirmed the previously reported deficit in hippocampal long-term potentiation and associated spatial learning impairment. RESULTS Despite a spatial learning deficit, mGlu5-deficient mice developed and maintained a conditioned place preference to cocaine, suggesting cocaine reward and Pavlovian conditioning are intact in these animals. Notably, however, mGlu5-deficient mice exhibited a marked deficit in the extinction of a cocaine-conditioned place preference compared to wild type littermates. Moreover, in a fixed ratio operant intravenous self-administration paradigm, both genotypes showed similar responding for cocaine over two different doses, while mGlu5-deficient mice displayed enhanced responding on a progressive ratio schedule. In addition, cue-induced drug-seeking after abstinence was exaggerated in mGlu5-deficient mice. CONCLUSION Collectively, these findings suggest that while the mGlu5 receptor may be involved in mediating the rewarding effects of cocaine, it appears necessary for the extinction of cocaine-driven behaviours.
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Affiliation(s)
- Michael K Bird
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, Australia
| | - Peter Lohmann
- The John Curtin School of Medical Research & Eccles Institute of Neuroscience, Australian National University, Canberra, Australia
| | - Billy West
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, Australia
| | - Robyn M Brown
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, Australia; Medical University of South Carolina, Charleston, SC, USA
| | - Jeppe Kirchhoff
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, Australia
| | - Clarke R Raymond
- The John Curtin School of Medical Research & Eccles Institute of Neuroscience, Australian National University, Canberra, Australia
| | - Andrew J Lawrence
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, Australia.
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153
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D'Antoni S, Spatuzza M, Bonaccorso CM, Musumeci SA, Ciranna L, Nicoletti F, Huber KM, Catania MV. Dysregulation of group-I metabotropic glutamate (mGlu) receptor mediated signalling in disorders associated with Intellectual Disability and Autism. Neurosci Biobehav Rev 2014; 46 Pt 2:228-41. [PMID: 24548786 DOI: 10.1016/j.neubiorev.2014.02.003] [Citation(s) in RCA: 73] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2013] [Revised: 01/13/2014] [Accepted: 02/06/2014] [Indexed: 12/11/2022]
Abstract
Activation of group-I metabotropic glutamate receptors, mGlu1 and mGlu5, triggers a variety of signalling pathways in neurons and glial cells, which are differently implicated in synaptic plasticity. The earliest and much of key studies discovered abnormal mGlu5 receptor function in Fragile X syndrome (FXS) mouse models which then motivated more recent work that finds mGlu5 receptor dysfunction in related disorders such as intellectual disability (ID), obsessive-compulsive disorder (OCD) and autism. Therefore, mGlu1/5 receptor dysfunction may represent a common aetiology of these complex diseases. Furthermore, many studies have focused on dysregulation of mGlu5 signalling to synaptic protein synthesis. However, emerging evidence finds abnormal mGlu5 receptor interactions with its scaffolding proteins in FXS which results in mGlu5 receptor dysfunction and phenotypes independent of signalling to protein synthesis. Finally, both an increased and reduced mGlu5 functioning seem to be associated with ID and autism spectrum disorders, with important consequences for potential treatment of these developmental disorders.
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Affiliation(s)
- Simona D'Antoni
- Institute of Neurological Sciences, the National Research Council of Italy (CNR), Catania, Italy
| | - Michela Spatuzza
- Institute of Neurological Sciences, the National Research Council of Italy (CNR), Catania, Italy
| | | | | | - Lucia Ciranna
- Department of Biomedical Sciences, section of Physiology, University of Catania, Italy
| | - Ferdinando Nicoletti
- IRCCS Neuromed, Pozzilli (IS), Italy; University of Rome La Sapienza, Rome, Italy
| | - Kimberly M Huber
- University of Texas Southwestern Medical Center, Department of Neuroscience, Dallas, TX 75390-9111, USA
| | - Maria Vincenza Catania
- Institute of Neurological Sciences, the National Research Council of Italy (CNR), Catania, Italy; IRCCS Oasi Maria SS, Troina (EN), Italy.
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154
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Yoo J, Bakes J, Bradley C, Collingridge GL, Kaang BK. Shank mutant mice as an animal model of autism. Philos Trans R Soc Lond B Biol Sci 2014; 369:20130143. [PMID: 24298145 PMCID: PMC3843875 DOI: 10.1098/rstb.2013.0143] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
In this review, we focus on the role of the Shank family of proteins in autism. In recent years, autism research has been flourishing. With genetic, molecular, imaging and electrophysiological studies being supported by behavioural studies using animal models, there is real hope that we may soon understand the fundamental pathology of autism. There is also genuine potential to develop a molecular-level pharmacological treatment that may be able to deal with the most severe symptoms of autism, and clinical trials are already underway. The Shank family of proteins has been strongly implicated as a contributing factor in autism in certain individuals and sits at the core of the alleged autistic pathway. Here, we analyse studies that relate Shank to autism and discuss what light this sheds on the possible causes of autism.
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Affiliation(s)
- Juyoun Yoo
- Department of Biological Sciences, Seoul National University, Gwanangno 599, Gwanak-gu, Seoul 151-747, SouthKorea
| | - Joseph Bakes
- Department of Brain and Cognitive Sciences, College of Natural Sciences, Seoul National University, Gwanangno 599, Gwanak-gu, Seoul 151-747, SouthKorea
| | - Clarrisa Bradley
- Department of Brain and Cognitive Sciences, College of Natural Sciences, Seoul National University, Gwanangno 599, Gwanak-gu, Seoul 151-747, SouthKorea
| | - Graham L. Collingridge
- Department of Brain and Cognitive Sciences, College of Natural Sciences, Seoul National University, Gwanangno 599, Gwanak-gu, Seoul 151-747, SouthKorea
- Centre for Synaptic Plasticity, University of Bristol, Whitson Street, Bristol BS1 3NY, UK
| | - Bong-Kiun Kaang
- Department of Biological Sciences, Seoul National University, Gwanangno 599, Gwanak-gu, Seoul 151-747, SouthKorea
- Department of Brain and Cognitive Sciences, College of Natural Sciences, Seoul National University, Gwanangno 599, Gwanak-gu, Seoul 151-747, SouthKorea
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155
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Poels EMP, Kegeles LS, Kantrowitz JT, Slifstein M, Javitt DC, Lieberman JA, Abi-Dargham A, Girgis RR. Imaging glutamate in schizophrenia: review of findings and implications for drug discovery. Mol Psychiatry 2014; 19:20-9. [PMID: 24166406 DOI: 10.1038/mp.2013.136] [Citation(s) in RCA: 144] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/23/2013] [Revised: 08/25/2013] [Accepted: 09/09/2013] [Indexed: 12/11/2022]
Abstract
Currently, all treatments for schizophrenia (SCZ) function primarily by blocking D(2)-type dopamine receptors. Given the limitations of these medications, substantial efforts have been made to identify alternative neurochemical targets for treatment development in SCZ. One such target is brain glutamate. The objective of this article is to review and synthesize the proton magnetic resonance spectroscopy ((1)H MRS) and positron emission tomography (PET)/single-photon emission computed tomography (SPECT) investigations that have examined glutamatergic indices in SCZ, including those of modulatory compounds such as glutathione (GSH) and glycine, as well as data from ketamine challenge studies. The reviewed (1)H MRS and PET/SPECT studies support the theory of hypofunction of the N-methyl-D-aspartate receptor (NMDAR) in SCZ, as well as the convergence between the dopamine and glutamate models of SCZ. We also review several advances in MRS and PET technologies that have opened the door for new opportunities to investigate the glutamate system in SCZ and discuss some ways in which these imaging tools can be used to facilitate a greater understanding of the glutamate system in SCZ and the successful and efficient development of new glutamate-based treatments for SCZ.
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Affiliation(s)
- E M P Poels
- 1] Department of Psychiatry, Columbia University College of Physicians and Surgeons, New York, NY, USA [2] New York State Psychiatric Institute, New York, NY, USA
| | - L S Kegeles
- 1] Department of Psychiatry, Columbia University College of Physicians and Surgeons, New York, NY, USA [2] New York State Psychiatric Institute, New York, NY, USA
| | - J T Kantrowitz
- 1] Department of Psychiatry, Columbia University College of Physicians and Surgeons, New York, NY, USA [2] New York State Psychiatric Institute, New York, NY, USA
| | - M Slifstein
- 1] Department of Psychiatry, Columbia University College of Physicians and Surgeons, New York, NY, USA [2] New York State Psychiatric Institute, New York, NY, USA
| | - D C Javitt
- 1] Department of Psychiatry, Columbia University College of Physicians and Surgeons, New York, NY, USA [2] New York State Psychiatric Institute, New York, NY, USA
| | - J A Lieberman
- 1] Department of Psychiatry, Columbia University College of Physicians and Surgeons, New York, NY, USA [2] New York State Psychiatric Institute, New York, NY, USA
| | - A Abi-Dargham
- 1] Department of Psychiatry, Columbia University College of Physicians and Surgeons, New York, NY, USA [2] New York State Psychiatric Institute, New York, NY, USA [3] Department of Radiology, Columbia University College of Physicians and Surgeons, New York, NY, USA
| | - R R Girgis
- 1] Department of Psychiatry, Columbia University College of Physicians and Surgeons, New York, NY, USA [2] New York State Psychiatric Institute, New York, NY, USA
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156
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Ribeiro FM, Devries RA, Hamilton A, Guimaraes IM, Cregan SP, Pires RGW, Ferguson SSG. Metabotropic glutamate receptor 5 knockout promotes motor and biochemical alterations in a mouse model of Huntington's disease. Hum Mol Genet 2013; 23:2030-42. [PMID: 24282028 DOI: 10.1093/hmg/ddt598] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Huntington's disease (HD) is an autosomal-dominant neurodegenerative disorder caused by a polyglutamine expansion in the amino-terminal region of the huntingtin protein, which promotes progressive neuronal cell loss, neurological symptoms and death. In the present study, we show that blockade of mGluR5 with MTEP promotes increased locomotor activity in both control (Hdh(Q20/Q20)) and mutant HD (Hdh(Q111/Q111)) mice. Although acute injection of MTEP increases locomotor activity in both control and mutant HD mice, locomotor activity is increased in only control mice, not mutant HD mice, following the genetic deletion of mGluR5. Interestingly, treatment of mGluR5 knockout mice with either D1 or D2 dopamine antagonists eliminates the increased locomotor activity of mGluR5 knockout mice. Amphetamine treatment increases locomotor activity in control mice, but not mGluR5 null mutant HD mice. However, the loss of mGluR5 expression improves rotarod performance and decreases the number of huntingtin intranuclear inclusions in mutant HD mice. These adaptations may be due to mutant huntingtin-dependent alterations in gene expression, as microarray studies have identified several genes that are altered in mutant, but not wild-type HD mice lacking mGluR5 expression. qPCR experiments confirm that the mRNA transcript levels of dynein heavy chain, dynactin 3 and dynein light chain-6 are altered following the genetic deletion of mGluR5 in mutant HD mice, as compared with wild-type mutant HD mice. Thus, our data suggest that mutant huntingtin protein and mGluR5 exhibit a functional interaction that may be important for HD-mediated alterations in locomotor behavior and the development of intranuclear inclusions.
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Affiliation(s)
- Fabiola M Ribeiro
- Departamento de Bioquimica e Imunologia, ICB, Universidade Federal de Minas Gerais, Belo Horizonte 31270-901, Brazil
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157
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Um JW, Kaufman AC, Kostylev M, Heiss JK, Stagi M, Takahashi H, Kerrisk ME, Vortmeyer A, Wisniewski T, Koleske AJ, Gunther EC, Nygaard HB, Strittmatter SM. Metabotropic glutamate receptor 5 is a coreceptor for Alzheimer aβ oligomer bound to cellular prion protein. Neuron 2013; 79:887-902. [PMID: 24012003 DOI: 10.1016/j.neuron.2013.06.036] [Citation(s) in RCA: 435] [Impact Index Per Article: 39.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/17/2013] [Indexed: 02/07/2023]
Abstract
Soluble amyloid-β oligomers (Aβo) trigger Alzheimer's disease (AD) pathophysiology and bind with high affinity to cellular prion protein (PrP(C)). At the postsynaptic density (PSD), extracellular Aβo bound to lipid-anchored PrP(C) activates intracellular Fyn kinase to disrupt synapses. Here, we screened transmembrane PSD proteins heterologously for the ability to couple Aβo-PrP(C) with Fyn. Only coexpression of the metabotropic glutamate receptor, mGluR5, allowed PrP(C)-bound Aβo to activate Fyn. PrP(C) and mGluR5 interact physically, and cytoplasmic Fyn forms a complex with mGluR5. Aβo-PrP(C) generates mGluR5-mediated increases of intracellular calcium in Xenopus oocytes and in neurons, and the latter is also driven by human AD brain extracts. In addition, signaling by Aβo-PrP(C)-mGluR5 complexes mediates eEF2 phosphorylation and dendritic spine loss. For mice expressing familial AD transgenes, mGluR5 antagonism reverses deficits in learning, memory, and synapse density. Thus, Aβo-PrP(C) complexes at the neuronal surface activate mGluR5 to disrupt neuronal function.
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Affiliation(s)
- Ji Won Um
- Cellular Neuroscience, Neurodegeneration and Repair Program, Departments of Neurology and Neurobiology, Yale University School of Medicine, New Haven, CT 06536, USA
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158
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Group I metabotropic glutamate receptors modulate late phase long-term potentiation in hippocampal CA1 pyramidal neurons: comparison of apical and basal dendrites. Neurosci Lett 2013; 553:132-7. [PMID: 23978512 DOI: 10.1016/j.neulet.2013.08.030] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2013] [Revised: 08/11/2013] [Accepted: 08/14/2013] [Indexed: 11/21/2022]
Abstract
The hippocampal long-term potentiation (LTP) at Schaffer collateral synapses onto CA1 pyramidal neurons has been widely studied as a cellular model of activity-dependent enhancement of synaptic transmission. The apical (stratum radiatum) and basal dendrites (stratum oriens) of hippocampal CA1 pyramidal neurons differ in LTP induction and maintenance. Here, the role of mGlu receptors in the induction and maintenance of late-LTP was investigated, in comparison of these two compartments. My results show that mGlu1 receptor modulates late-LTP in apical dendrites and basal dendrites, whereas mGlu5 receptor modulates late-LTP only in apical dendrites.
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159
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Gould TJ, Leach PT. Cellular, molecular, and genetic substrates underlying the impact of nicotine on learning. Neurobiol Learn Mem 2013; 107:108-32. [PMID: 23973448 DOI: 10.1016/j.nlm.2013.08.004] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2013] [Revised: 08/13/2013] [Accepted: 08/13/2013] [Indexed: 12/27/2022]
Abstract
Addiction is a chronic disorder marked by long-lasting maladaptive changes in behavior and in reward system function. However, the factors that contribute to the behavioral and biological changes that occur with addiction are complex and go beyond reward. Addiction involves changes in cognitive control and the development of disruptive drug-stimuli associations that can drive behavior. A reason for the strong influence drugs of abuse can exert on cognition may be the striking overlap between the neurobiological substrates of addiction and of learning and memory, especially areas involved in declarative memory. Declarative memories are critically involved in the formation of autobiographical memories, and the ability of drugs of abuse to alter these memories could be particularly detrimental. A key structure in this memory system is the hippocampus, which is critically involved in binding multimodal stimuli together to form complex long-term memories. While all drugs of abuse can alter hippocampal function, this review focuses on nicotine. Addiction to tobacco products is insidious, with the majority of smokers wanting to quit; yet the majority of those that attempt to quit fail. Nicotine addiction is associated with the presence of drug-context and drug-cue associations that trigger drug seeking behavior and altered cognition during periods of abstinence, which contributes to relapse. This suggests that understanding the effects of nicotine on learning and memory will advance understanding and potentially facilitate treating nicotine addiction. The following sections examine: (1) how the effects of nicotine on hippocampus-dependent learning change as nicotine administration transitions from acute to chronic and then to withdrawal from chronic treatment and the potential impact of these changes on addiction, (2) how nicotine usurps the cellular mechanisms of synaptic plasticity, (3) the physiological changes in the hippocampus that may contribute to nicotine withdrawal deficits in learning, and (4) the role of genetics and developmental stage (i.e., adolescence) in these effects.
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Affiliation(s)
- Thomas J Gould
- Temple University Department of Psychology, Neuroscience Program, Temple University, Philadelphia, PA 19122, United States.
| | - Prescott T Leach
- Temple University Department of Psychology, Neuroscience Program, Temple University, Philadelphia, PA 19122, United States
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160
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Jew CP, Wu CS, Sun H, Zhu J, Huang JY, Yu D, Justice NJ, Lu HC. mGluR5 ablation in cortical glutamatergic neurons increases novelty-induced locomotion. PLoS One 2013; 8:e70415. [PMID: 23940572 PMCID: PMC3734292 DOI: 10.1371/journal.pone.0070415] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2013] [Accepted: 06/23/2013] [Indexed: 01/05/2023] Open
Abstract
The group I metabotropic glutamate receptor 5 (mGluR5) has been implicated in the pathology of various neurological disorders including schizophrenia, ADHD, and autism. mGluR5-dependent synaptic plasticity has been described at a variety of neural connections and its signaling has been implicated in several behaviors. These behaviors include locomotor reactivity to novel environment, sensorimotor gating, anxiety, and cognition. mGluR5 is expressed in glutamatergic neurons, inhibitory neurons, and glia in various brain regions. In this study, we show that deleting mGluR5 expression only in principal cortical neurons leads to defective cannabinoid receptor 1 (CB1R) dependent synaptic plasticity in the prefrontal cortex. These cortical glutamatergic mGluR5 knockout mice exhibit increased novelty-induced locomotion, and their locomotion can be further enhanced by treatment with the psychostimulant methylphenidate. Despite a modest reduction in repetitive behaviors, cortical glutamatergic mGluR5 knockout mice are normal in sensorimotor gating, anxiety, motor balance/learning and fear conditioning behaviors. These results show that mGluR5 signaling in cortical glutamatergic neurons is required for precisely modulating locomotor reactivity to a novel environment but not for sensorimotor gating, anxiety, motor coordination, several forms of learning or social interactions.
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Affiliation(s)
- Chris P. Jew
- The Cain Foundation Laboratories, Baylor College of Medicine, Houston, Texas, United States of America
- Jan and Dan Duncan Neurological Research Institute at Texas Children’s Hospital, Baylor College of Medicine, Houston, Texas, United States of America
- Department of Pediatrics, Baylor College of Medicine, Houston, Texas, United States of America
| | - Chia-Shan Wu
- The Cain Foundation Laboratories, Baylor College of Medicine, Houston, Texas, United States of America
- Jan and Dan Duncan Neurological Research Institute at Texas Children’s Hospital, Baylor College of Medicine, Houston, Texas, United States of America
- Department of Pediatrics, Baylor College of Medicine, Houston, Texas, United States of America
| | - Hao Sun
- The Cain Foundation Laboratories, Baylor College of Medicine, Houston, Texas, United States of America
- Jan and Dan Duncan Neurological Research Institute at Texas Children’s Hospital, Baylor College of Medicine, Houston, Texas, United States of America
- Department of Pediatrics, Baylor College of Medicine, Houston, Texas, United States of America
| | - Jie Zhu
- The Cain Foundation Laboratories, Baylor College of Medicine, Houston, Texas, United States of America
- Jan and Dan Duncan Neurological Research Institute at Texas Children’s Hospital, Baylor College of Medicine, Houston, Texas, United States of America
- Department of Pediatrics, Baylor College of Medicine, Houston, Texas, United States of America
| | - Jui-Yen Huang
- The Cain Foundation Laboratories, Baylor College of Medicine, Houston, Texas, United States of America
- Jan and Dan Duncan Neurological Research Institute at Texas Children’s Hospital, Baylor College of Medicine, Houston, Texas, United States of America
- Department of Pediatrics, Baylor College of Medicine, Houston, Texas, United States of America
| | - Dinghui Yu
- Jan and Dan Duncan Neurological Research Institute at Texas Children’s Hospital, Baylor College of Medicine, Houston, Texas, United States of America
- Department of Pediatrics, Baylor College of Medicine, Houston, Texas, United States of America
| | - Nicholas J. Justice
- Huffington Center on Aging, Baylor College of Medicine, Houston, Texas, United States of America
| | - Hui-Chen Lu
- The Cain Foundation Laboratories, Baylor College of Medicine, Houston, Texas, United States of America
- Jan and Dan Duncan Neurological Research Institute at Texas Children’s Hospital, Baylor College of Medicine, Houston, Texas, United States of America
- Department of Pediatrics, Baylor College of Medicine, Houston, Texas, United States of America
- Huffington Center on Aging, Baylor College of Medicine, Houston, Texas, United States of America
- Program in Developmental Biology, Baylor College of Medicine, Houston, Texas, United States of America
- Department of Neuroscience, Baylor College of Medicine, Houston, Texas, United States of America
- * E-mail:
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161
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Chesworth R, Brown RM, Kim JH, Lawrence AJ. The metabotropic glutamate 5 receptor modulates extinction and reinstatement of methamphetamine-seeking in mice. PLoS One 2013; 8:e68371. [PMID: 23861896 PMCID: PMC3701637 DOI: 10.1371/journal.pone.0068371] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2013] [Accepted: 05/29/2013] [Indexed: 12/12/2022] Open
Abstract
Methamphetamine (METH) is a highly addictive psychostimulant with no therapeutics registered to assist addicts in discontinuing use. Glutamatergic dysfunction has been implicated in the development and maintenance of addiction. We sought to assess the involvement of the metabotropic glutamate 5 receptor (mGlu5) in behaviours relevant to METH addiction because this receptor has been implicated in the actions of other drugs of abuse, including alcohol, cocaine and opiates. mGlu5 knockout (KO) mice were tested in intravenous self-administration, conditioned place preference and locomotor sensitization. Self-administration of sucrose was used to assess the response of KO mice to a natural reward. Acquisition and maintenance of self-administration, as well as the motivation to self-administer METH was intact in mGlu5 KO mice. Importantly, mGlu5 KO mice required more extinction sessions to extinguish the operant response for METH, and exhibited an enhanced propensity to reinstate operant responding following exposure to drug-associated cues. This phenotype was not present when KO mice were tested in an equivalent paradigm assessing operant responding for sucrose. Development of conditioned place preference and locomotor sensitization were intact in KO mice; however, conditioned hyperactivity to the context previously paired with drug was elevated in KO mice. These data demonstrate a role for mGlu5 in the extinction and reinstatement of METH-seeking, and suggests a role for mGlu5 in regulating contextual salience.
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Affiliation(s)
- Rose Chesworth
- Behavioural Neuroscience Division, Florey Institute of Neuroscience and Mental Health, Parkville, Victoria, Australia
- Florey Department of Neuroscience and Mental Health, University of Melbourne, Parkville, Victoria, Australia
| | - Robyn M. Brown
- Behavioural Neuroscience Division, Florey Institute of Neuroscience and Mental Health, Parkville, Victoria, Australia
- Florey Department of Neuroscience and Mental Health, University of Melbourne, Parkville, Victoria, Australia
- Department of Neurosciences, Medical University of South Carolina, Charleston, South Carolina, United States of America
| | - Jee Hyun Kim
- Behavioural Neuroscience Division, Florey Institute of Neuroscience and Mental Health, Parkville, Victoria, Australia
- Florey Department of Neuroscience and Mental Health, University of Melbourne, Parkville, Victoria, Australia
| | - Andrew J. Lawrence
- Behavioural Neuroscience Division, Florey Institute of Neuroscience and Mental Health, Parkville, Victoria, Australia
- Florey Department of Neuroscience and Mental Health, University of Melbourne, Parkville, Victoria, Australia
- * E-mail:
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Liu MG, Kang SJ, Shi TY, Koga K, Zhang MM, Collingridge GL, Kaang BK, Zhuo M. Long-term potentiation of synaptic transmission in the adult mouse insular cortex: multielectrode array recordings. J Neurophysiol 2013; 110:505-21. [PMID: 23636718 DOI: 10.1152/jn.01104.2012] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
The insular cortex (IC) is widely believed to be an important forebrain structure involved in cognitive and sensory processes such as memory and pain. However, little work has been performed at the cellular level to investigate the synaptic basis of IC-related brain functions. To bridge the gap, the present study was designed to characterize the basic synaptic mechanisms for insular long-term potentiation (LTP). Using a 64-channel recording system, we found that an enduring form of late-phase LTP (L-LTP) could be reliably recorded for at least 3 h in different layers of IC slices after theta burst stimulation. The induction of insular LTP is protein synthesis dependent and requires activation of both GluN2A and GluN2B subunits of the NMDA receptor, L-type voltage-gated calcium channels, and metabotropic glutamate receptor 1. The paired-pulse facilitation ratio was unaffected by insular L-LTP induction, and expression of insular L-LTP required the recruitment of postsynaptic calcium-permeable AMPA receptors. Our results provide the first in vitro report of long-term multichannel recordings of L-LTP in the IC in adult mice and suggest its potential important roles in insula-related memory and chronic pain.
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Affiliation(s)
- Ming-Gang Liu
- Department of Brain and Cognitive Sciences, College of Natural Sciences, Seoul National University, Seoul, Korea
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163
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Baker KD, Edwards TM, Rickard NS. The role of intracellular calcium stores in synaptic plasticity and memory consolidation. Neurosci Biobehav Rev 2013; 37:1211-39. [PMID: 23639769 DOI: 10.1016/j.neubiorev.2013.04.011] [Citation(s) in RCA: 74] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2013] [Revised: 04/18/2013] [Accepted: 04/22/2013] [Indexed: 12/20/2022]
Abstract
Memory processing requires tightly controlled signalling cascades, many of which are dependent upon intracellular calcium (Ca(2+)). Despite this, most work investigating calcium signalling in memory formation has focused on plasma membrane channels and extracellular sources of Ca(2+). The intracellular Ca(2+) release channels, ryanodine receptors (RyRs) and inositol (1,4,5)-trisphosphate receptors (IP3Rs) have a significant capacity to regulate intracellular Ca(2+) signalling. Evidence at both cellular and behavioural levels implicates both RyRs and IP3Rs in synaptic plasticity and memory formation. Pharmacobehavioural experiments using young chicks trained on a single-trial discrimination avoidance task have been particularly useful by demonstrating that RyRs and IP3Rs have distinct roles in memory formation. RyR-dependent Ca(2+) release appears to aid the consolidation of labile memory into a persistent long-term memory trace. In contrast, IP3Rs are required during long-term memory. This review discusses various functions for RyRs and IP3Rs in memory processing, including neuro- and glio-transmitter release, dendritic spine remodelling, facilitating vasodilation, and the regulation of gene transcription and dendritic excitability. Altered Ca(2+) release from intracellular stores also has significant implications for neurodegenerative conditions.
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Affiliation(s)
- Kathryn D Baker
- School of Psychology and Psychiatry, Monash University, Clayton 3800, Victoria, Australia.
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Prepulse inhibition predicts working memory performance whilst startle habituation predicts spatial reference memory retention in C57BL/6 mice. Behav Brain Res 2013; 242:166-77. [DOI: 10.1016/j.bbr.2012.12.011] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2012] [Revised: 12/01/2012] [Accepted: 12/06/2012] [Indexed: 12/26/2022]
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Mao SC, Chang CH, Wu CC, Orejanera MJ, Manzoni OJ, Gean PW. Inhibition of spontaneous recovery of fear by mGluR5 after prolonged extinction training. PLoS One 2013; 8:e59580. [PMID: 23555716 PMCID: PMC3605338 DOI: 10.1371/journal.pone.0059580] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2012] [Accepted: 02/15/2013] [Indexed: 11/19/2022] Open
Abstract
Fear behavior is vital for survival and involves learning contingent associations of non-threatening cues with aversive stimuli. In contrast, excessive levels of fear can be maladaptive and lead to anxiety disorders. Generally, extensive sessions of extinction training correlates with reduced spontaneous recovery. The molecular mechanisms underlying the long-term inhibition of fear recovery following repeated extinction training are not fully understood. Here we show that in rats, prolonged extinction training causes greater reduction in both fear-potentiated startle and spontaneous recovery. This effect was specifically blocked by metabotropic glutamate receptor 5 (mGluR5), but not by mGluR1 antagonists and by a protein synthesis inhibitor. Similar inhibition of memory recovery following prolonged extinction training was also observed in mice. In agreement with the instrumental role of mGluR5 in the prolonged inhibition of fear recovery, we found that FMR1-/- mice which exhibit enhanced mGluR5-mediated signaling exhibit lower spontaneous recovery of fear after extinction training than wild-type littermates. At the molecular level, we discovered that prolonged extinction training reversed the fear conditioning-induced increase in surface expression of GluR1, AMPA/NMDA ratio, postsynaptic density-95 (PSD-95) and synapse-associated protein-97 (SAP97). Accordingly, delivery of Tat-GluR2(3Y), a synthetic peptide that blocks AMPA receptor endocytosis, inhibited prolonged extinction training-induced inhibition of fear recovery. Together, our results demonstrate that prolonged extinction training results in the mGluR5-dependent long-term inhibition of fear recovery. This effect may involve the degradation of original memory and may explain the beneficial effects of prolonged exposure therapy for the treatment of phobias.
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Affiliation(s)
- Sheng-Chun Mao
- Institute of Basic Medical Sciences and Department of Pharmacology, National Cheng-Kung University, Tainan, Taiwan
| | - Chih-Hua Chang
- Institute of Basic Medical Sciences and Department of Pharmacology, National Cheng-Kung University, Tainan, Taiwan
| | - Chia-Chen Wu
- Institute of Basic Medical Sciences and Department of Pharmacology, National Cheng-Kung University, Tainan, Taiwan
| | | | | | - Po-Wu Gean
- Institute of Basic Medical Sciences and Department of Pharmacology, National Cheng-Kung University, Tainan, Taiwan
- * E-mail: (P-WG); (OJM)
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166
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Haug MF, Gesemann M, Mueller T, Neuhauss SC. Phylogeny and expression divergence of metabotropic glutamate receptor genes in the brain of zebrafish (Danio rerio). J Comp Neurol 2013; 521:1533-60. [DOI: 10.1002/cne.23240] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2011] [Revised: 04/05/2012] [Accepted: 10/02/2012] [Indexed: 12/15/2022]
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167
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Mukherjee S, Manahan-Vaughan D. Role of metabotropic glutamate receptors in persistent forms of hippocampal plasticity and learning. Neuropharmacology 2013; 66:65-81. [DOI: 10.1016/j.neuropharm.2012.06.005] [Citation(s) in RCA: 85] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2012] [Revised: 05/31/2012] [Accepted: 06/01/2012] [Indexed: 12/27/2022]
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Paquet M, Ribeiro FM, Guadagno J, Esseltine JL, Ferguson SSG, Cregan SP. Role of metabotropic glutamate receptor 5 signaling and homer in oxygen glucose deprivation-mediated astrocyte apoptosis. Mol Brain 2013; 6:9. [PMID: 23406666 PMCID: PMC3598502 DOI: 10.1186/1756-6606-6-9] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2013] [Accepted: 02/11/2013] [Indexed: 02/03/2023] Open
Abstract
BACKGROUND Group I metabotropic glutamate receptors (mGluR) are coupled via Gαq/11 to the activation of phospholipase Cβ, which hydrolyzes membrane phospholipids to form inositol 1,4,5 trisphosphate and diacylglycerol. In addition to functioning as neurotransmitter receptors to modulate synaptic activity, pathological mGluR5 signaling has been implicated in a number of disease processes including Fragile X, amyotrophic lateral sclerosis, multiple sclerosis, Alzheimer's disease, Parkinson's disease, Huntington's disease, epilepsy, and drug addiction. The expression of mGluR5 in astrocytes has been shown to be increased in several acute and chronic neurodegenerative conditions, but little is known about the functional relevance of mGluR5 up-regulation in astrocytes following injury. RESULTS In the current study, we investigated primary mouse cortical astrocyte cell death in response to oxygen glucose deprivation (OGD) and found that OGD induced both necrotic and apoptotic cell death of astrocytes. OGD resulted in an increase in astrocytic mGluR5 protein expression, inositol phosphate formation and extracellular regulated kinase (ERK1/2) phosphorylation, but only inositol phosphate formation was blocked with the mGluR5 selective antagonist MPEP. Cortical astrocytes derived from mGluR5 knockout mice exhibited resistance to OGD-stimulated apoptosis, but a lack of mGluR5 expression did not confer protection against necrotic cell death. The antagonism of the inositol 1,4,5 trisphosphate receptor also reduced apoptotic cell death in wild-type astrocytes, but did not provide any additional protection to astrocytes derived from mGluR5 null mice. Moreover, the disruption of Homer protein interactions with mGluR5 also reduced astrocyte apoptosis. CONCLUSION Taken together these observations indicated that mGluR5 up-regulation contributed selectively to the apoptosis of astrocytes via the activation of phospholipase C and the release of calcium from intracellular stores as well as via the association with Homer proteins.
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Affiliation(s)
- Maryse Paquet
- J, Allyn Taylor Centre for Cell Biology, Robarts Research Institute, Department of Physiology and Pharmacology, The University of Western Ontario, 100 Perth Drive, London, ON, N6A 5K8, Canada
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Parkitna JR, Sikora M, Gołda S, Gołembiowska K, Bystrowska B, Engblom D, Bilbao A, Przewlocki R. Novelty-seeking behaviors and the escalation of alcohol drinking after abstinence in mice are controlled by metabotropic glutamate receptor 5 on neurons expressing dopamine d1 receptors. Biol Psychiatry 2013; 73:263-70. [PMID: 22902169 DOI: 10.1016/j.biopsych.2012.07.019] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/18/2012] [Revised: 06/15/2012] [Accepted: 07/05/2012] [Indexed: 12/28/2022]
Abstract
BACKGROUND Novel experiences activate the brain's reward system in a manner similar to drugs of abuse, and high levels of novelty-seeking and sensation-seeking behavior have been associated with increased susceptibility to alcohol and drug abuse. Here, we show that metabotropic glutamate receptor 5 (mGluR5) signaling on dopaminoceptive neurons is necessary for both novelty-seeking behavior and the abstinence-induced escalation of alcohol drinking. METHODS Mice harboring a transgene expressing microRNA hairpins against mGluR5 messenger RNA under the control of the D1 dopamine receptor gene promoter (mGluR5(KD-D1)) were tested in a battery of behavioral tests measuring learning abilities, anxiety levels, reactions to novelty, operant sensation seeking, and alcohol sensitivity. In addition, we have developed a method to assess long-term patterns of alcohol drinking in mice housed in groups using the IntelliCage system. RESULTS mGluR5(KD-D1) mice showed no behavioral deficits and exhibited normal anxiety-like behaviors and learning abilities. However, mGluR5(KD-D1) animals showed reduced locomotor activity when placed in a novel environment, and exhibited decreased interaction with a novel object. Moreover, unlike control animals, mutant mice did not perform instrumental responses under the operant sensation-seeking paradigm, although they learned to respond for food normally. When mGluR5(KD-D1) mice were provided access to alcohol, they showed similar patterns of consumption as wild-type animals. However, mutant mice did not escalate their alcohol consumption after a period of forced abstinence, but control mice almost doubled their intake. CONCLUSIONS These data identify mGluR5 receptors on D1-expressing neurons as a common molecular substrate of novelty-seeking behaviors and behaviors associated with alcohol abuse.
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Affiliation(s)
- Jan Rodriguez Parkitna
- Department of Molecular Neuropharmacology, Institute of Pharmacology of the Polish Academy of Sciences, Krakow, Poland
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170
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Clifton NE, Morisot N, Girardon S, Millan MJ, Loiseau F. Enhancement of social novelty discrimination by positive allosteric modulators at metabotropic glutamate 5 receptors: adolescent administration prevents adult-onset deficits induced by neonatal treatment with phencyclidine. Psychopharmacology (Berl) 2013; 225:579-94. [PMID: 22983144 DOI: 10.1007/s00213-012-2845-3] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/22/2012] [Accepted: 08/08/2012] [Indexed: 12/20/2022]
Abstract
Metabotropic glutamate-5 receptors (mGluR5), which physically and functionally interact with N-methyl-D-Aspartate (NMDA) receptors, likewise control cognitive processes and have been proposed as targets for novel classes of antipsychotic agent. Since social cognition is impaired in schizophrenia and disrupted by NMDA receptor antagonists like dizocilpine, we evaluated its potential modulation by mGluR5. Acute administration (0.63-40 mg/kg) of the mGluR5 positive allosteric modulators (PAMs), 3-cyano-N-(1,3-diphenyl-1H-pyrazol-5-yl)benzamide (CDPPB) and ADX47273, reversed a delay-induced impairment in social novelty discrimination (SND) in adult rats. The action of CDPPB was blocked by the mGluR5 antagonist, 2-methyl-6-(phenylethynyl)-pyridine (2.5-10 mg/kg), and was also expressed upon microinjection into frontal cortex (0.63-10 μg/side), but not striatum. Supporting an interrelationship between mGluR5 and NMDA receptors, enhancement of SND by CDPPB was blocked by dizocilpine (0.08 mg/kg) while, reciprocally, dizocilpine-induced impairment in SND was attenuated by CDPPB (10 mg/kg). The SND deficit elicited by post-natal administration of phencyclidine (10 mg/kg, days 7-11) was reversed by CDPPB or ADX47273 in adults at week 8. This phencyclidine-induced impairment in cognition emerged in adult rats from week 7 on, and chronic, pre-symptomatic treatment of adolescent rats with CDPPB over weeks 5-6 (10 mg/kg per day) prevented the appearance of SND deficits in adults until at least week 13. In conclusion, as evaluated by a SND procedure, mGluR5 PAMs promote social cognition via actions expressed in interaction with NMDA receptors and exerted in frontal cortex. MGluR5 PAMs not only reverse but also (when given during adolescence) prevent the emergence of cognitive impairment associated with a developmental model of schizophrenia.
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Affiliation(s)
- Nicholas E Clifton
- Neuroscience Research and Development Unit, Institut de Recherches Servier, 125 Chemin de ronde, Croissy-sur-Seine, Paris, France
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171
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Parmentier-Batteur S, Hutson PH, Menzel K, Uslaner JM, Mattson BA, O'Brien JA, Magliaro BC, Forest T, Stump CA, Tynebor RM, Anthony NJ, Tucker TJ, Zhang XF, Gomez R, Huszar SL, Lambeng N, Fauré H, Le Poul E, Poli S, Rosahl TW, Rocher JP, Hargreaves R, Williams TM. Mechanism based neurotoxicity of mGlu5 positive allosteric modulators--development challenges for a promising novel antipsychotic target. Neuropharmacology 2013; 82:161-73. [PMID: 23291536 DOI: 10.1016/j.neuropharm.2012.12.003] [Citation(s) in RCA: 72] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2012] [Revised: 12/06/2012] [Accepted: 12/11/2012] [Indexed: 11/17/2022]
Abstract
Previous work has suggested that activation of mGlu5 receptor augments NMDA receptor function and thereby may constitute a rational approach addressing glutamate hypofunction in schizophrenia and a target for novel antipsychotic drug development. Here, we report the in vitro activity, in vivo efficacy and safety profile of 5PAM523 (4-Fluorophenyl){(2R,5S)-5-[5-(5-fluoropyridin-2-yl)-1,2,4-oxadiazol-3-yl]-2-methylpiperidin-1-yl}methanone), a structurally novel positive allosteric modulator selective of mGlu5. In cells expressing human mGlu5 receptor, 5PAM523 potentiated threshold responses to glutamate in fluorometric calcium assays, but does not have any intrinsic agonist activity. 5PAM523 acts as an allosteric modulator as suggested by the binding studies showing that 5PAM523 did not displace the binding of the orthosteric ligand quisqualic acid, but did partially compete with the negative allosteric modulator, MPyEP. In vivo, 5PAM523 reversed amphetamine-induced locomotor activity in rats. Therefore, both the in vitro and in vivo data demonstrate that 5PAM523 acts as a selective mGlu5 PAM and exhibits anti-psychotic like activity. To study the potential for adverse effects and particularly neurotoxicity, brain histopathological exams were performed in rats treated for 4 days with 5PAM523 or vehicle. The brain exam revealed moderate to severe neuronal necrosis in the rats treated with the doses of 30 and 50 mg/kg, particularly in the auditory cortex and hippocampus. To investigate whether this neurotoxicity is mechanism specific to 5PAM523, similar safety studies were carried out with three other structurally distinct selective mGlu5 PAMs. Results revealed a comparable pattern of neuronal cell death. Finally, 5PAM523 was tested in mGlu5 knock-out (KO) and wild type (WT) mice. mGlu5 WT mice treated with 5PAM523 for 4 days at 100 mg/kg presented significant neuronal death in the auditory cortex and hippocampus. Conversely, mGlu5 KO mice did not show any neuronal loss by histopathology, suggesting that enhancement of mGlu5 function is responsible for the toxicity of 5PAM523. This study reveals for the first time that augmentation of mGlu5 function with selective allosteric modulators results in neurotoxicity.
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Affiliation(s)
| | - Peter H Hutson
- Merck Research Laboratories, 770 Sumneytown Pike, West Point, PA 19486-0004, USA
| | - Karsten Menzel
- Merck Research Laboratories, 770 Sumneytown Pike, West Point, PA 19486-0004, USA
| | - Jason M Uslaner
- Merck Research Laboratories, 770 Sumneytown Pike, West Point, PA 19486-0004, USA
| | - Britta A Mattson
- Merck Research Laboratories, 770 Sumneytown Pike, West Point, PA 19486-0004, USA
| | - Julie A O'Brien
- Merck Research Laboratories, 770 Sumneytown Pike, West Point, PA 19486-0004, USA
| | - Brian C Magliaro
- Merck Research Laboratories, 770 Sumneytown Pike, West Point, PA 19486-0004, USA
| | - Thomas Forest
- Merck Research Laboratories, 770 Sumneytown Pike, West Point, PA 19486-0004, USA
| | - Craig A Stump
- Merck Research Laboratories, 770 Sumneytown Pike, West Point, PA 19486-0004, USA
| | - Robert M Tynebor
- Merck Research Laboratories, 770 Sumneytown Pike, West Point, PA 19486-0004, USA
| | - Neville J Anthony
- Merck Research Laboratories, 770 Sumneytown Pike, West Point, PA 19486-0004, USA
| | - Thomas J Tucker
- Merck Research Laboratories, 770 Sumneytown Pike, West Point, PA 19486-0004, USA
| | - Xu-Fang Zhang
- Merck Research Laboratories, 770 Sumneytown Pike, West Point, PA 19486-0004, USA
| | - Robert Gomez
- Merck Research Laboratories, 770 Sumneytown Pike, West Point, PA 19486-0004, USA
| | - Sarah L Huszar
- Merck Research Laboratories, 770 Sumneytown Pike, West Point, PA 19486-0004, USA
| | - Nathalie Lambeng
- Addex Therapeutics, 12, chemin des Aulx, 1228 Plan-les-Ouates, Geneva, Switzerland
| | - H Fauré
- Addex Therapeutics, 12, chemin des Aulx, 1228 Plan-les-Ouates, Geneva, Switzerland
| | - Emannuel Le Poul
- Addex Therapeutics, 12, chemin des Aulx, 1228 Plan-les-Ouates, Geneva, Switzerland
| | - Sonia Poli
- Addex Therapeutics, 12, chemin des Aulx, 1228 Plan-les-Ouates, Geneva, Switzerland
| | - Thomas W Rosahl
- Merck Research Laboratories, 770 Sumneytown Pike, West Point, PA 19486-0004, USA
| | - Jean-Philippe Rocher
- Addex Therapeutics, 12, chemin des Aulx, 1228 Plan-les-Ouates, Geneva, Switzerland
| | - Richard Hargreaves
- Merck Research Laboratories, 770 Sumneytown Pike, West Point, PA 19486-0004, USA
| | - Theresa M Williams
- Merck Research Laboratories, 770 Sumneytown Pike, West Point, PA 19486-0004, USA
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Sephton SM, Mu L, Müller A, Wanger-Baumann CA, Schibli R, Krämer SD, Ametamey SM. Synthesis and in vitro/in vivo pharmacological evaluation of [11C]-ThioABP, a novel radiotracer for imaging mGluR5 with PET. MEDCHEMCOMM 2013. [DOI: 10.1039/c2md20332d] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Pharmacology of metabotropic glutamate receptor allosteric modulators: structural basis and therapeutic potential for CNS disorders. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2013; 115:61-121. [PMID: 23415092 DOI: 10.1016/b978-0-12-394587-7.00002-6] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
The metabotropic glutamate receptors (mGlus) mediate a neuromodulatory role throughout the brain for the major excitatory neurotransmitter, glutamate. Seven of the eight mGlu subtypes are expressed within the CNS and are attractive targets for a variety of psychiatric and neurological disorders including anxiety, depression, schizophrenia, Parkinson's disease, and Fragile X syndrome. Allosteric modulation of these class C 7-transmembrane spanning receptors represents a novel approach to facilitate development of mGlu subtype-selective probes and therapeutics. Allosteric modulators that interact with sites topographically distinct from the endogenous ligand-binding site offer a number of advantages over their competitive counterparts. In particular for CNS therapeutics, allosteric modulators have the potential to maintain the spatial and temporal aspects of endogenous neurotransmission. The past 15 years have seen the discovery of numerous subtype-selective allosteric modulators for the majority of the mGlu family members, including positive, negative, and neutral allosteric modulators, with a number of mGlu allosteric modulators now in clinical trials.
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174
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Matosin N, Newell KA. Metabotropic glutamate receptor 5 in the pathology and treatment of schizophrenia. Neurosci Biobehav Rev 2012; 37:256-68. [PMID: 23253944 DOI: 10.1016/j.neubiorev.2012.12.005] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2012] [Revised: 10/27/2012] [Accepted: 12/09/2012] [Indexed: 02/07/2023]
Abstract
Metabotropic glutamate receptor 5 (mGluR5) potentiates the NMDA receptor (NMDAR) in brain regions implicated in schizophrenia, making it a viable therapeutic target for the treatment of this disorder. mGluR5 positive allosteric modulators may represent a valuable novel strategy for schizophrenia treatment, given the favourable profile of effects in preclinical paradigms. However it remains unclear whether mGluR5 also plays a causal or epiphenomenal role in NMDAR dysfunction in schizophrenia. Animal and cellular data suggest involvement of mGluR5, whilst post-mortem human studies remain inconclusive. This review will explore the molecular, animal and human data to support and refute the involvement of mGluR5 in the pathology of schizophrenia. Furthermore, this review will discuss the potential of mGluR5 modulators in the therapy of schizophrenia as well as aspects of mGluR5 that require further characterisation.
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Affiliation(s)
- Natalie Matosin
- Centre for Translational Neuroscience, Illawarra Health and Medical Research Institute, School of Health Sciences, University of Wollongong, NSW 2522, Australia
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175
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Inta D, Vogt MA, Luoni A, Filipović D, Lima-Ojeda JM, Pfeiffer N, Gasparini F, Riva MA, Gass P. Significant increase in anxiety during aging in mGlu5 receptor knockout mice. Behav Brain Res 2012; 241:27-31. [PMID: 23228523 DOI: 10.1016/j.bbr.2012.11.042] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2012] [Revised: 11/25/2012] [Accepted: 11/29/2012] [Indexed: 10/27/2022]
Abstract
Glutamatergic mechanisms regulate neuronal circuits implicated in mood and anxiety. Emotional disorders as anxiety and depression are particularly difficult to treat during aging and mechanisms underlying emotional disturbances in the brain of the elderly are poorly understood. This may result from the small number of studies investigating these disorders in aged animals. Among glutamate receptors, metabotropic mGlu5 receptors are thought to play an important role, since their pharmacological blockade induces strong anxiolytic effects. However, the implication of mGlu5 in regulating anxiety is not yet completely understood. Here we analyzed both young adult and aged mice lacking mGlu5 receptors, to clarify, if genetic deletion of the receptor induces similar to pharmacological blockade anxiolytic effects. Unexpectedly, mGlu5 receptor knockout (KO) mice showed increased anxiety accentuating with aging. In contrast, young adult mice displayed an anti-depressive-like phenotype that was no longer detectable in aged animals. Our data support important distinct roles of mGlu5 receptors in modulating anxiety and depression during aging.
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Affiliation(s)
- D Inta
- RG Animal Models in Psychiatry, Department of Psychiatry and Psychotherapy, Central Institute of Mental Health, Medical Faculty Mannheim/Heidelberg, Germany.
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176
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Yang P, Zhang J, Zhao L, Jiao Q, Jin H, Xiao X, Zhang H, Hu M, Lu H, Liu Y. Developmental distribution pattern of metabotropic glutamate receptor 5 in prenatal human hippocampus. Neurosci Bull 2012; 28:704-14. [PMID: 23225313 DOI: 10.1007/s12264-012-1286-7] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2012] [Accepted: 05/17/2012] [Indexed: 12/23/2022] Open
Abstract
OBJECTIVE Metabotropic glutamate receptor 5 (mGluR5) is concentrated in zones of active neurogenesis in the prenatal and postnatal rodent brain and plays an important role in the regulation of neurogenesis. However, little is known about mGluR5 in the prenatal human brain. Here, we aimed to explore the expression pattern and cellular distribution of mGluR5 in human fetal hippocampus. METHODS Thirty-four human fetuses were divided into four groups according to gestational age: 9-11, 14-16, 22-24 and 32-36 weeks. The hippocampus was dissected out and prepared. The protein and mRNA expression of mGluR5 were evaluated by Western blot and immunohistochemistry or real-time PCR. The cellular distribution of mGluR5 was observed with double-labeling immunofluorescence. RESULTS Both mGluR5 mRNA and protein were detected in the prenatal human hippocampus by real-time PCR and immunoblotting, and the expression levels increased gradually over time. The immunohistochemistry results were consistent with immunoblotting and showed that mGluR5 immunoreactivity was mainly present in the inner marginal zone (IMZ), hippocampal plate (HP) and ventricular zone (VZ). The double-labeling immunofluorescence showed that mGluR5 was present in neural stem cells (nestin-positive), neuroblasts (DCX-positive) and mature neurons (NeuN-positive), but not in typical astrocytes (GFAP-positive). The cells co-expressing mGluR5 and nestin were mainly located in the IMZ, HP and subplate at 11 weeks, all layers at 16 weeks, and CA1 at 24 weeks. As development proceeded, the number of mGluR5/nestin double-positive cells decreased gradually so that there were only a handful of double-labeled cells at 32 weeks. However, mGluR5/DCX double-positive cells were only found in the HP, IZ and IMZ at 11 weeks. CONCLUSION The pattern of mGluR5 expression by neural stem/progenitor cells, neuroblasts and neurons provides important anatomical evidence for the role of mGluR5 in the regulation of human hippocampal development.
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Affiliation(s)
- Pengbo Yang
- Institute of Neurobiology, Key Laboratory for Environment and Genes Related to Diseases of the Ministry of Education, Xi'an Jiaotong University College of Medicine, Xi'an 710061, China
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Fowler SW, Walker JM, Klakotskaia D, Will MJ, Serfozo P, Simonyi A, Schachtman TR. Effects of a metabotropic glutamate receptor 5 positive allosteric modulator, CDPPB, on spatial learning task performance in rodents. Neurobiol Learn Mem 2012; 99:25-31. [PMID: 23137441 DOI: 10.1016/j.nlm.2012.10.010] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2012] [Revised: 10/10/2012] [Accepted: 10/23/2012] [Indexed: 11/28/2022]
Abstract
Metabotropic glutamate receptor 5 (mGlu5) has been implicated in a variety of learning and memory processes and is important for avoidance learning. The present studies used an mGlu5 receptor positive allosteric modulator, 3-cyano-N-(1,3 diphenyl-1H-hyrazol-5-yl)benzamide (CDPPB), to characterize the importance of mGlu5 receptors in aversively- and appetitively-motivated spatial learning tasks (tasks in which the instrumental contingency involves discriminative cues that differ in spatial location). C57Bl/6 male mice were initially trained in the Barnes maze in the absence of drug. Subsequently, CDPPB (30mg/kg, i.p.), administered 20min prior to each of 3 daily reversal learning training sessions in the Barnes maze, significantly enhanced performance compared to vehicle-treated controls and had a significant effect on search strategy. Mice treated with CDPPB also displayed significantly less perseverative behavior than control-treated animals. In a second experiment, male Sprague-Dawley rats were trained in an appetitively-motivated, delayed alternation version of a T-maze. 30mg/kg CDPPB (s.c.), delivered 20min prior to each of 5 daily training sessions, enhanced the delay rats were able to withstand between the sample and choice portions of each T-maze trial. The present results emphasize the role of mGlu5 receptors in spatial learning tasks and support previous studies which report mGlu5 positive allosteric modulators can enhance learning in some tasks and may have potential as nootropic drugs.
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Affiliation(s)
- S W Fowler
- Department of Psychological Sciences, University of Missouri, Columbia, MO 65211, United States
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178
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Abstract
Clinical studies report associations between cannabis use during adolescence and later onset of schizophrenia. We examined the causal relationship between developmental cannabinoid administration and long-term behavioral and molecular alterations in mice. Mice were administered either WIN 55,212-2 (WIN), a cannabinoid receptor 1 (CB1) agonist or vehicle (Veh) during adolescence (postnatal day 30-35) or early adulthood (postnatal day 63-70). Behavioral testing was conducted after postnatal day 120 followed by biochemical assays. Adolescent cannabinoid treatment (ACU) leads to deficits in prepulse inhibition and fear conditioning in adulthood. Metabotropic glutamate receptors type 5 (mGluR5), a receptor critically involved in fear conditioning and endocannabinoid (eCB) signaling, is significantly reduced in the ACU mouse hippocampus. Next, we examined expression profiles of genes involved in eCB synthesis (diacylglycerol lipase (DGL)) and uptake (monoacylglycerol lipase (MGL) and fatty acid amide hydrolase (FAAH)) in the experimental mice. We find evidence of increased MGL and FAAH in ACU mice, reflecting increases in eCB uptake and degradation. These data suggest that administration of cannabinoids during adolescence leads to a behavioral phenotype associated with a rodent model of schizophrenia, as indexed by alterations in sensorimotor gating and hippocampal-dependent learning and memory deficits. Further, these deficits are associated with a reduction in hippocampal mGluR5 and a sustained change in eCB turnover, suggesting reduced eCB signaling in the ACU hippocampus. These data suggest that significant cannabis use during adolescence may be a contributory causal factor in the development of certain features of schizophrenia and may offer mGluR5 as a potential therapeutic target.
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179
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Minami K, Uezono Y. The recent progress in research on effects of anesthetics and analgesics on G protein-coupled receptors. J Anesth 2012; 27:284-92. [PMID: 23099434 DOI: 10.1007/s00540-012-1507-2] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2012] [Accepted: 10/09/2012] [Indexed: 11/25/2022]
Abstract
The exact mechanisms of action behind anesthetics and analgesics are still unclear. Much attention was focused on ion channels in the central nervous system as targets for anesthetics and analgesics in the 1980s. During the 1990s, major advances were made in our understanding of the physiology and pharmacology of G protein coupled receptor (GPCR) signaling. Thus, several lines of studies have shown that G protein coupled receptors (GPCRs) are one of the targets for anesthetics and analgesics and especially, that some of them inhibit the functions of GPCRs, i.e,, muscarinic receptors and substance P receptors. However, these studies had been focused on only G(q) coupled receptors. There has been little work on G(s)- and G(i)-coupled receptors. In the last decade, a new assay system, using chimera G(i/o)-coupled receptor fused to Gq(i5), has been established and the effects of anesthetics and analgesics on the function of G(i)-coupled receptors is now more easily studied. This review highlights the recent progress of the studies regarding the effects of anesthetics and analgesics on GPCRs.
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Affiliation(s)
- Kouichiro Minami
- Cancer Pathophysiology Division, National Cancer Center Research Institute, Tokyo 104-0045, Japan.
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180
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Goh JJ, Manahan-Vaughan D. Endogenous hippocampal LTD that is enabled by spatial object recognition requires activation of NMDA receptors and the metabotropic glutamate receptor, mGlu5. Hippocampus 2012; 23:129-38. [DOI: 10.1002/hipo.22072] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/06/2012] [Indexed: 12/24/2022]
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181
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Hu JH, Yang L, Kammermeier PJ, Moore CG, Brakeman PR, Tu J, Yu S, Petralia RS, Li Z, Zhang PW, Park JM, Dong X, Xiao B, Worley PF. Preso1 dynamically regulates group I metabotropic glutamate receptors. Nat Neurosci 2012; 15:836-44. [PMID: 22561452 DOI: 10.1038/nn.3103] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2012] [Accepted: 04/03/2012] [Indexed: 01/13/2023]
Abstract
Group I metabotropic glutamate receptors (mGluRs), including mGluR1 and mGluR5, are G protein–coupled receptors (GPCRs) that are expressed at excitatory synapses in brain and spinal cord. GPCRs are often negatively regulated by specific G protein–coupled receptor kinases and subsequent binding of arrestin-like molecules. Here we demonstrate an alternative mechanism in which group I mGluRs are negatively regulated by proline-directed kinases that phosphorylate the binding site for the adaptor protein Homer, and thereby enhance mGluR–Homer binding to reduce signaling. This mechanism is dependent on a multidomain scaffolding protein, Preso1, that binds mGluR, Homer and proline-directed kinases and that is required for their phosphorylation of mGluR at the Homer binding site. Genetic ablation of Preso1 prevents dynamic phosphorylation of mGluR5, and Preso1(−/−) mice exhibit sustained, mGluR5-dependent inflammatory pain that is linked to enhanced mGluR signaling. Preso1 creates a microdomain for proline-directed kinases with broad substrate specificity to phosphorylate mGluR and to mediate negative regulation.
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Affiliation(s)
- Jia-Hua Hu
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD, USA
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182
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Rossi PIA, Musante I, Summa M, Pittaluga A, Emionite L, Ikehata M, Rastaldi MP, Ravazzolo R, Puliti A. Compensatory molecular and functional mechanisms in nervous system of the Grm1(crv4) mouse lacking the mGlu1 receptor: a model for motor coordination deficits. ACTA ACUST UNITED AC 2012; 23:2179-89. [PMID: 22791805 DOI: 10.1093/cercor/bhs200] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
The metabotropic glutamate type 1 (mGlu1) and type 5 (mGlu5) receptors, the only members of group I mGlu receptors, are implicated in synaptic plasticity and mechanisms of feedback control of glutamate release. They exhibit nearly complementary distributions throughout the central nervous system, well evident in the cerebellum, where mGlu1 receptor is most intensely expressed while mGlu5 receptor is not. Despite their different distribution, they show a similar subcellular localization and use common transducing pathways. We recently described the Grm1(crv4) mouse with motor coordination deficits and renal anomalies caused by a spontaneous mutation inactivating the mGlu1 receptor. To define the neuropathological mechanisms in these mice, we evaluated expression and function of the mGlu5 receptor in cerebral and cerebellar cortices. Western blot and immunofluorescence analyses showed mGlu5 receptor overexpression. Quantitative reverse transcriptase-polymerase chain reaction results indicated that the up-regulation is already evident at RNA level. Functional studies confirmed an enhanced glutamate release from cortical cerebral and cerebellar synaptosomes when compared with wild-type that is abolished by the mGlu5 receptor-specific inhibitor, 2-methyl-6-(phenylethynyl) pyridine hydrochloride (MPEP). Finally, acute MPEP treatment of Grm1(crv4/crv4) mice induced an evident although incomplete improvement of motor coordination, suggesting that mGlu5 receptors enhanced activity worsens, instead of improving, the motor-coordination defects in the Grm1(crv4/crv4) mice.
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183
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Kwag J, Paulsen O. Gating of NMDA receptor-mediated hippocampal spike timing-dependent potentiation by mGluR5. Neuropharmacology 2012; 63:701-9. [PMID: 22652057 PMCID: PMC3396853 DOI: 10.1016/j.neuropharm.2012.05.021] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2012] [Revised: 05/14/2012] [Accepted: 05/15/2012] [Indexed: 12/21/2022]
Abstract
Hippocampal long-term potentiation (LTP) is believed to be important for learning and memory. Experimentally, the pairing of precisely timed pre- and postsynaptic spikes within a time window of ∼10 ms can induce timing-dependent LTP (tLTP), but the requirements for induction of tLTP change with development: in young rodents single postsynaptic spikes are sufficient to induce tLTP, whereas postsynaptic burst firing appears to be required in the adult. However, hippocampal neurons in vivo show theta-modulated single spike activities also in older hippocampus. Here we investigated the conditions for single spike pairing to induce tLTP at older CA3–CA1 synapses. We found that the pairing of single pre- and postsynaptic spikes could induce tLTP in older hippocampus when the postsynaptic neuronal membrane was depolarized and the pairing frequency exceeded ∼4 Hz. The spike frequency requirement is postsynaptic, as tLTP could still be induced with presynaptic stimulation at 1 Hz as long as the postsynaptic spike frequency exceeded ∼4 Hz, suggesting that postsynaptic theta-frequency activity is required for the successful induction of tLTP at older CA3–CA1 synapses. The induction of tLTP was blocked by an NMDA receptor antagonist and by the selective mGluR5 blockers, MPEP and MTEP, whereas activation of mGluR1 and mGluR5 by DHPG relieved the postsynaptic spike frequency requirement for tLTP induction. These results suggest that activation of mGluR5 during single-spike pairing at older CA3–CA1 synapses gates NMDA receptor-dependent tLTP.
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Affiliation(s)
- Jeehyun Kwag
- Department of Brain and Cognitive Engineering, Korea University, 145 Anam-Ro, Seongbuk-Gu, Seoul 136-701, Republic of Korea.
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184
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Chaki S, Ago Y, Palucha-Paniewiera A, Matrisciano F, Pilc A. mGlu2/3 and mGlu5 receptors: potential targets for novel antidepressants. Neuropharmacology 2012; 66:40-52. [PMID: 22640631 DOI: 10.1016/j.neuropharm.2012.05.022] [Citation(s) in RCA: 93] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2012] [Revised: 04/27/2012] [Accepted: 05/15/2012] [Indexed: 02/06/2023]
Abstract
Major depressive disorder is among the most prevalent forms of mental illness. All currently available antidepressant medications have stemmed from study of the mechanisms of serendipitously discovered drugs, and only 30-50% of patients exhibit remission and frequently at least 3-4 weeks are required for manifestation of significant therapeutic effects. To overcome these drawbacks, discovering novel neuronal mechanisms of pathophysiology of depression as well as more effective treatments are necessary. This review focuses on the metabotropic glutamate (mGlu) receptors and their potential for drug targets for the treatment of depression. In particular, accumulating evidence has indicated the potential importance and usefulness of agents acting on mGlu2/3 and mGlu5 receptors. Preclinical and clinical evidence of mGlu2/3 receptor ligands and mGlu5 receptor antagonists are described. Moreover, their potential in clinic will be discussed in the context of neuronal mechanisms of ketamine, an agent recently demonstrated a robust effect for patients with treatment-resistant depression. This article is part of a Special Issue entitled 'Metabotropic Glutamate Receptors'.
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Affiliation(s)
- Shigeyuki Chaki
- Discovery Pharmacology, Molecular Function and Pharmacology Laboratories, Taisho Pharmaceutical Co., Ltd., 1-403 Yoshino-cho, Kita-ku, Saitama, Saitama 331-9530, Japan.
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185
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Kato HK, Kassai H, Watabe AM, Aiba A, Manabe T. Functional coupling of the metabotropic glutamate receptor, InsP3 receptor and L-type Ca2+ channel in mouse CA1 pyramidal cells. J Physiol 2012; 590:3019-34. [PMID: 22586220 DOI: 10.1113/jphysiol.2012.232942] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Activity-dependent regulation of calcium dynamics in neuronal cells can play significant roles in the modulation of many cellular processes such as intracellular signalling, neuronal activity and synaptic plasticity. Among many calcium influx pathways into neurons, the voltage-dependent calcium channel (VDCC) is the major source of calcium influx, but its modulation by synaptic activity has still been under debate. While the metabotropic glutamate receptor (mGluR) is supposed to modulate L-type VDCCs (L-VDCCs), its reported actions include both facilitation and suppression, probably reflecting the uncertainty of both the molecular targets of the mGluR agonists and the source of the recorded calcium signal in previous reports. In this study, using subtype-specific knockout mice, we have shown that mGluR5 induces facilitation of the depolarization-evoked calcium current. This facilitation was not accompanied by the change in single-channel properties of the VDCC itself; instead, it required the activation of calcium-induced calcium release (CICR) that was triggered by VDCC opening, suggesting that the opening of CICR-coupled cation channels was essential for the facilitation. This facilitation was blocked or reduced by the inhibitors of both L-VDCCs and InsP3 receptors (InsP3Rs). Furthermore, L-VDCCs and mGluR5 were shown to form a complex by coimmunoprecipitation, suggesting that the specific functional coupling between mGluR5, InsP3Rs and L-VDCCs played a pivotal role in the calcium-current facilitation. Finally, we showed that mGluR5 enhanced VDCC-dependent long-term potentiation (LTP) of synaptic transmission. Our study has identified a novel mechanism of the interaction between the mGluR and calcium signalling, and suggested a contribution of mGluR5 to synaptic plasticity.
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Affiliation(s)
- Hiroyuki K Kato
- Division of Neuronal Network, Department of Basic Medical Sciences, Institute of Medical Science, University of Tokyo, Tokyo, 108-8639, Japan
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186
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Crock LW, Stemler KM, Song DG, Abbosh P, Vogt SK, Qiu CS, Lai HH, Mysorekar IU, Gereau RW. Metabotropic glutamate receptor 5 (mGluR5) regulates bladder nociception. Mol Pain 2012; 8:20. [PMID: 22449017 PMCID: PMC3369204 DOI: 10.1186/1744-8069-8-20] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2012] [Accepted: 03/26/2012] [Indexed: 01/28/2023] Open
Abstract
BACKGROUND Interstitial cystitis/painful bladder syndrome (IC/PBS), is a severely debilitating chronic condition that is frequently unresponsive to conventional pain medications. The etiology is unknown, however evidence suggests that nervous system sensitization contributes to enhanced pain in IC/PBS. In particular, central nervous system plasticity of glutamatergic signaling involving NMDA and metabotropic glutamate receptors (mGluRs) has been implicated in a variety of chronic pain conditions. Here, we test the hypothesis that mGluR5 mediates both non-inflammatory and inflammatory bladder pain or nociception in a mouse model by monitoring the visceromotor response (VMR) during graded bladder distention. RESULTS Using a combination of genetic and pharmacologic approaches, we provide evidence indicating that mGluR5 is necessary for the full expression of VMR in response to bladder distention in the absence of inflammation. Furthermore, we observed that mice infected with a uropathogenic strain of Escherichia coli (UPEC) develop inflammatory hyperalgesia to bladder distention, and that the selective mGluR5 antagonist fenobam [N-(3-chlorophenyl)-N'-(4,5-dihydro-1-methyl-4-oxo-1H-imidazole-2-yl) urea], reduces the VMR to bladder distention in UPEC-infected mice. CONCLUSIONS Taken together, these data suggest that mGluR5 modulates both inflammatory and non-inflammatory bladder nociception, and highlight the therapeutic potential for mGluR5 antagonists in the alleviation of bladder pain.
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Affiliation(s)
- Lara W Crock
- Neuroscience Program, Washington University School of Medicine, St, Louis, MO 63110, USA
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187
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Elmenhorst D, Aliaga A, Bauer A, Rosa-Neto P. Test-retest stability of cerebral mGluR₅ quantification using [¹¹C]ABP688 and positron emission tomography in rats. Synapse 2012; 66:552-60. [PMID: 22290765 DOI: 10.1002/syn.21542] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2011] [Accepted: 01/24/2012] [Indexed: 11/07/2022]
Abstract
This study evaluates the reproducibility of the quantification of metabotropic glutamate receptor type 5 (mGluR₅) densities in rats using the PET radiotracer [¹¹C]ABP688 and pharmacokinetic models that are based on an input function, which is derived from a reference tissue. Seven rats underwent dynamic PET scans (60 min) after bolus injection of [¹¹C]ABP688. Kinetic analyses included: binding potential (BP(ND) ) determined by calculating (a) the simplified reference tissue model (SRTM) and (b) its two-steps simplified version (SRTM2); (c) multilinear reference tissue model (MRTM) and (d) its 2-parameter version (MRTM2); (e) noninvasive graphical analysis (NIGA). Parametric images were generated representing BP(ND) by the MRTM2 model. BP(ND) determinations were reproducible with low to acceptable variability ranging from 5 to 10% and reproducibility scores (intraclass correlation coefficient) between 0.51 and 0.88. The pharmacokinetic model that showed lowest overall variability was the SRTM. In contrast, the use of the NIGA was associated with significantly lower reproducibility scores. Comparison of parametric images revealed no significant bias between test and retest measurements and is therefore suitable to compare groups at voxel levels. In conclusion, our results suggest that noninvasive quantification of [¹¹C]ABP688 imaging is reproducible and reliable for PET studies of the cerebral mGluR₅ in rats.
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Affiliation(s)
- David Elmenhorst
- Translational Neuroimaging Laboratory, McGill Center for Studies in Aging, Douglas Research Institute, Montreal, Quebec, Canada
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188
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Vinson PN, Conn PJ. Metabotropic glutamate receptors as therapeutic targets for schizophrenia. Neuropharmacology 2012; 62:1461-72. [PMID: 21620876 PMCID: PMC3189289 DOI: 10.1016/j.neuropharm.2011.05.005] [Citation(s) in RCA: 72] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2010] [Revised: 05/02/2011] [Accepted: 05/08/2011] [Indexed: 01/13/2023]
Abstract
Treatment options for schizophrenia that address all symptom categories (positive, negative, and cognitive) are lacking in current therapies for this disorder. Compounds targeting the metabotropic glutamate (mGlu) receptors hold promise as a more comprehensive therapeutic alternative to typical and atypical antipsychotics and may avoid the occurrence of extrapyramidal side effects that accompany these treatments. Activation of the group II mGlu receptors (mGlu(2) and mGlu(3)) and the group I mGlu(5) are hypothesized to normalize the disruption of thalamocortical glutamatergic circuitry that results in abnormal glutamaterigic signaling in the prefrontal cortex (PFC). Agonists of mGlu(2) and mGlu(3) have demonstrated efficacy for the positive symptom group in both animal models and clinical trials with mGlu(2) being the subtype most likely responsible for the therapeutic effect. Limitations in the chemical space tolerated by the orthosteric site of the mGlu receptors has led to the pursuit of compounds that potentiate the receptor's response to glutamate by acting at less highly conserved allosteric sites. Several series of selective positive allosteric modulators (PAMs) for mGlu(2) and mGlu(5) have demonstrated efficacy in animal models used for the evaluation of antipsychotic agents. In addition, evidence from animal studies indicates that mGlu(5) PAMs hold promise for the treatment of cognitive deficits that occur in schizophrenia. Hopefully, further optimization of allosteric modulators of mGlu receptors will yield clinical candidates that will allow full evaluation of the potential efficacy of these compounds in the treatment of multiple symptom domains in schizophrenia patients in the near future.
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Affiliation(s)
- Paige N. Vinson
- Vanderbilt University Medical Center, Department of Pharmacology and Vanderbilt Center for Neuroscience Drug Discovery, Nashville, TN 37202
| | - P. Jeffrey Conn
- Vanderbilt University Medical Center, Department of Pharmacology and Vanderbilt Center for Neuroscience Drug Discovery, Nashville, TN 37202
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189
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Herman EJ, Bubser M, Conn PJ, Jones CK. Metabotropic glutamate receptors for new treatments in schizophrenia. Handb Exp Pharmacol 2012:297-365. [PMID: 23027420 DOI: 10.1007/978-3-642-25758-2_11] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Metabotropic glutamate receptors (mGluRs) represent exciting targets for the development of novel therapeutic agents for schizophrenia. Recent studies indicate that selective activation of specific mGluR subtypes may provide potential benefits for not only the positive symptoms, but also the negative symptoms and cognitive impairments observed in individuals with schizophrenia. Although optimization of traditional orthosteric agonists may still offer a feasible approach for the activation of mGluRs, important progress has been made in the discovery of novel subtype-selective allosteric ligands, including positive allosteric modulators (PAMs) of mGluR2 and mGluR5. These allosteric mGluR ligands have improved properties for clinical development and have served as key preclinical tools for a more in-depth understanding of the potential roles of these different mGluR subtypes for the treatment of schizophrenia.
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Affiliation(s)
- E J Herman
- Vanderbilt Center for Neuroscience Drug Discovery, Vanderbilt University Medical Center, Nashville, TN 37232, USA
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190
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Thomas AM, Bui N, Perkins JR, Yuva-Paylor LA, Paylor R. Group I metabotropic glutamate receptor antagonists alter select behaviors in a mouse model for fragile X syndrome. Psychopharmacology (Berl) 2012; 219:47-58. [PMID: 21656124 DOI: 10.1007/s00213-011-2375-4] [Citation(s) in RCA: 75] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/08/2011] [Accepted: 05/30/2011] [Indexed: 11/25/2022]
Abstract
RATIONALE Studies in the Fmr1 knockout (KO) mouse, a model of fragile X syndrome (FXS), suggest that excessive signaling through group I metabotropic glutamate receptors (mGluRs), comprised of subtypes mGluR1 and mGluR5, may play a role in the pathogenesis of FXS. Currently, no studies have assessed the effect of mGluR1 modulation on Fmr1 KO behavior, and there has not been an extensive behavioral analysis of mGluR5 manipulation in Fmr1 KO mice. OBJECTIVES The goals for this study were to determine if pharmacologic blockade of mGluR1 may affect Fmr1 KO behavior as well as to expand on the current literature regarding pharmacologic blockade of mGluR5 on Fmr1 KO behavior. METHODS Reduction of mGluR1 or mGluR5 activity was evaluated on a variety of behavioral assays in wild-type (WT) and Fmr1 KO mice through the use of antagonists: JNJ16259685 (JNJ, mGluR1 antagonist) and MPEP (mGluR5 antagonist). RESULTS JNJ and MPEP decreased marble burying in both WT and Fmr1 KO mice without reductions in activity. Neither JNJ nor MPEP affected the prepulse inhibition in either WT or Fmr1 KO mice. JNJ did not affect Fmr1 KO motor coordination but did impair WT performance. MPEP improved a measure of motor learning in Fmr1 KO but not WT mice. While both JNJ and MPEP decreased the audiogenic seizures in the Fmr1 KO, MPEP completely abolished the manifestation of seizures. CONCLUSION These data illustrate that, while the manipulation of either mGluR1 or mGluR5 can affect select behaviors in the Fmr1 KO, we observe greater effects upon mGluR5 reduction.
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Affiliation(s)
- Alexia M Thomas
- Department of Neuroscience, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA
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191
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Abstract
ADHD is a common and highly heritable disorder. Family, twin, and adoption studies confirm a strong genetic influence in risk for ADHD and there has been a great deal of interest in identifying the genetic factors involved. Quantitative genetic studies find that genetic risk for ADHD is continuously distributed throughout the population, that there are both shared and unique genetic influences on inattention and hyperactivity-impulsivity, and that ADHD shares genetic risk factors with commonly co-occurring clinical syndromes and traits. ADHD is found at all ages and the underlying genetic architecture is similar across the lifespan. In terms of specific genetic findings, there is consistent evidence of monoamine neurotransmitter involvement with the best evidence coming from genetic markers in or near the dopamine D4 and D5 receptor genes. Recent genome-wide association studies have identified new association findings, including genes involved in cell division, cell adhesion, neuronal migration, and neuronal plasticity. However, as yet, none of these pass genome-wide levels of significance. Finally, recent data confirm an important role for rare copy number variants, including those that are found in schizophrenia and autism. Future work should use genetic association data to determine the nature of the cognitive, neuronal and cellular processes that mediate genetic risks on behaviour, and identify environmental factors that interact with genetic risks for ADHD.
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Affiliation(s)
- Philip Asherson
- MRC Social Genetic and Developmental Psychiatry, Institute of Psychiatry, Kings College London, London, UK,
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192
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Sephton SM, Dennler P, Leutwiler DS, Mu L, Wanger-Baumann CA, Schibli R, Krämer SD, Ametamey SM. Synthesis, radiolabelling and in vitro and in vivo evaluation of a novel fluorinated ABP688 derivative for the PET imaging of metabotropic glutamate receptor subtype 5. AMERICAN JOURNAL OF NUCLEAR MEDICINE AND MOLECULAR IMAGING 2011; 2:14-28. [PMID: 23133799 PMCID: PMC3478118] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 11/06/2011] [Accepted: 11/20/2011] [Indexed: 06/01/2023]
Abstract
(E)-3-(Pyridin-2-ylethynyl)cyclohex-2-enone O-(2-(3-(18)F-fluoropropoxy)ethyl) oxime ([(18)F]-PSS223) was evaluated in vitro and in vivo to establish its potential as a PET tracer for imaging metabotropic glutamate receptor subtype 5 (mGluR5). [(18)F]-PSS223 was obtained in 20% decay corrected radiochemical yield whereas the non-radioactive PSS223 was accomplished in 70% chemical yield in a S(N)2 reaction of common intermediate mesylate 8 with potassium fluoride. The in vitro binding affinity of [(18)F]-PSS223 was measured directly in a Scatchard assay to give K(d) = 3.34 ± 2.05 nM. [(18)F]-PSS223 was stable in PBS and rat plasma but was significantly metabolized by rat liver microsomal enzymes, but to a lesser extent by human liver microsomes. Within 60 min, 90% and 20% of [(18)F]-PSS223 was metabolized by rat and human microsome enzymes, respectively. In vitro autoradiography on horizontal rat brain slices showed heterogeneous distribution of [(18)F]-PSS223 with the highest accumulation in brain regions where mGluR5 is highly expressed (hippocampus, striatum and cortex). Autoradiography in vitro under blockade conditions with ABP688 confirmed the high specificity of [(18)F]-PSS223 for mGluR5. Under the same blocking conditions but using the mGluR1 antagonist, JNJ16259685, no blockade was observed demonstrating the selectivity of [(18)F]-PSS223 for mGluR5 over mGluR1. Despite favourable in vitro properties of [(18)F]-PSS223, a clear-cut visualization of mGluR5-rich brain regions in vivo in rats was not possible mainly due to a fast clearance from the brain and low metabolic stability of [(18)F]-PSS223.
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Affiliation(s)
- Selena Milicevic Sephton
- Center for Radiopharmaceutical Sciences of ETH, PSI and USZ, Department of Chemistry and Applied Biosciences of ETH Zurich Wolfgang-Pauli Strasse 10, 8093 Zurich, Switzerland
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Counteracting roles of metabotropic glutamate receptor subtypes 1 and 5 in regulation of pain-related spatial and temporal synaptic plasticity in rat entorhinal-hippocampal pathways. Neurosci Lett 2011; 507:38-42. [PMID: 22172929 DOI: 10.1016/j.neulet.2011.11.046] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2011] [Revised: 11/21/2011] [Accepted: 11/23/2011] [Indexed: 11/22/2022]
Abstract
It was previously found that persistent inflammatory pain state resulted in enhancement of synaptic connections and efficacy in direct entorhinal-hippocampal (EC-HIP) pathways. In the current study, the roles of two subtypes of group I metabotropic glutamate receptors in the above processes were evaluated. Similarly, pain-related spatial and temporal synaptic enhancement model was stably achieved by the multi-electrode array (8×8) recordings in the hippocampal slices of rats pre-treated with intraplantar (i.pl.) bee venom (BV) injection. I.pl. saline injection was used as control. Inhibition of mGluR1 by a selective antagonist 7-hydroxyiminocyclopropan [b] chromen-1α-carboxylic acid ethyl ester (CPCCOEt) resulted in a dramatic increase in synaptic connections in the hippocampal slices of rats treated by BV, but not by saline. However, inhibition of mGluR5 by a selective antagonist 2-methyl-6-(phenylethynyl)-pyridine (MPEP) produced no spatial change from either of the two groups. Temporally, the BV-enhanced LTP could be further incremented by antagonism of mGluR1 with CPCCOEt perfusion when plateau LTP was well established. However, the BV-enhanced LTP was significantly suppressed by antagonism of mGluR5 with MPEP. Neither of the two drugs affected magnitude of LTP in rats treated by i.pl. saline. Taken together with our previous results, it is suggested that mGluR1 be involved in tonic inhibition of EC-HIP synaptic enhancement, while mGluR5 be involved in maintenance of persistent inflammatory pain-associated EC-HIP synaptic enhancement that is largely based upon activation of ionic glutamate receptors.
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194
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Mutations causing syndromic autism define an axis of synaptic pathophysiology. Nature 2011; 480:63-8. [PMID: 22113615 PMCID: PMC3228874 DOI: 10.1038/nature10658] [Citation(s) in RCA: 469] [Impact Index Per Article: 36.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2011] [Accepted: 10/21/2011] [Indexed: 02/06/2023]
Abstract
Tuberous sclerosis complex and fragile X syndrome are genetic diseases characterized by intellectual disability and autism. Because both syndromes are caused by mutations in genes that regulate protein synthesis in neurons, it has been hypothesized that excessive protein synthesis is one core pathophysiological mechanism of intellectual disability and autism. Using electrophysiological and biochemical assays of neuronal protein synthesis in the hippocampus of Tsc2+/− and Fmr1−/y mice, we show that synaptic dysfunction caused by these mutations actually falls at opposite ends of a physiological spectrum. Synaptic, biochemical and cognitive defects in these mutants are corrected by treatments that modulate metabotropic glutamate receptor 5 in opposite directions, and deficits in the mutants disappear when the mice are bred to carry both mutations. Thus, normal synaptic plasticity and cognition occur within an optimal range of metabotropic glutamate receptor-mediated protein synthesis, and deviations in either direction can lead to shared behavioral impairments.
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195
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Noetzel MJ, Rook JM, Vinson PN, Cho HP, Days E, Zhou Y, Rodriguez AL, Lavreysen H, Stauffer SR, Niswender CM, Xiang Z, Daniels JS, Jones CK, Lindsley CW, Weaver CD, Conn PJ. Functional impact of allosteric agonist activity of selective positive allosteric modulators of metabotropic glutamate receptor subtype 5 in regulating central nervous system function. Mol Pharmacol 2011; 81:120-33. [PMID: 22021324 DOI: 10.1124/mol.111.075184] [Citation(s) in RCA: 102] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Positive allosteric modulators (PAMs) of metabotropic glutamate receptor subtype 5 (mGlu(5)) have emerged as an exciting new approach for the treatment of schizophrenia and other central nervous system (CNS) disorders. Of interest, some mGlu(5) PAMs act as pure PAMs, only potentiating mGlu(5) responses to glutamate whereas others [allosteric agonists coupled with PAM activity (ago-PAMs)] potentiate responses to glutamate and have intrinsic allosteric agonist activity in mGlu(5)-expressing cell lines. All mGlu(5) PAMs previously shown to have efficacy in animal models act as ago-PAMs in cell lines, raising the possibility that allosteric agonist activity is critical for in vivo efficacy. We have now optimized novel mGlu(5) pure PAMs that are devoid of detectable agonist activity and structurally related mGlu(5) ago-PAMs that activate mGlu(5) alone in cell lines. Studies of mGlu(5) PAMs in cell lines revealed that ago-PAM activity is dependent on levels of mGlu(5) receptor expression in human embryonic kidney 293 cells, whereas PAM potency is relatively unaffected by levels of receptor expression. Furthermore, ago-PAMs have no agonist activity in the native systems tested, including cortical astrocytes and subthalamic nucleus neurons and in measures of long-term depression at the hippocampal Schaffer collateral-CA1 synapse. Finally, studies with pure PAMs and ago-PAMs chemically optimized to provide comparable CNS exposure revealed that both classes of mGlu(5) PAMs have similar efficacy in a rodent model predictive of antipsychotic activity. These data suggest that the level of receptor expression influences the ability of mGlu(5) PAMs to act as allosteric agonists in vitro and that ago-PAM activity observed in cell-based assays may not be important for in vivo efficacy.
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Affiliation(s)
- Meredith J Noetzel
- Department of Pharmacology and Vanderbilt Center for Neuroscience Drug Discovery, Vanderbilt University Medical Center, Nashville, Tennessee 37232-0697, USA
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196
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Fatemi SH, Folsom TD, Kneeland RE, Liesch SB. Metabotropic glutamate receptor 5 upregulation in children with autism is associated with underexpression of both Fragile X mental retardation protein and GABAA receptor beta 3 in adults with autism. Anat Rec (Hoboken) 2011; 294:1635-45. [PMID: 21901840 PMCID: PMC3177171 DOI: 10.1002/ar.21299] [Citation(s) in RCA: 110] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2010] [Accepted: 05/13/2010] [Indexed: 11/08/2022]
Abstract
Recent work has demonstrated the impact of dysfunction of the GABAergic signaling system in brain and the resultant behavioral pathologies in subjects with autism. In animal models, altered expression of Fragile X mental retardation protein (FMRP) has been linked to downregulation of GABA receptors. Interestingly, the autistic phenotype is also observed in individuals with Fragile X syndrome. This study was undertaken to test previous theories relating abnormalities in levels of FMRP to GABA(A) receptor underexpression. We observed a significant reduction in levels of FMRP in the vermis of adults with autism. Additionally, we found that levels of metabotropic glutamate receptor 5 (mGluR5) protein were significantly increased in vermis of children with autism versus age and postmortem interval matched controls. There was also a significant decrease in level of GABA(A) receptor beta 3 (GABRβ3) protein in vermis of adult subjects with autism. Finally, we found significant increases in glial fibrillary acidic protein in vermis of both children and adults with autism when compared with controls. Taken together, our results provide further evidence that altered FMRP expression and increased mGluR5 protein production potentially lead to altered expression of GABA(A) receptors.
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Affiliation(s)
- S Hossein Fatemi
- Department of Psychiatry, Division of Neuroscience Research, University of Minnesota Medical School, Minneapolis, USA.
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197
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Nisticò R, Dargan SL, Amici M, Collingridge GL, Bortolotto ZA. Synergistic interactions between kainate and mGlu receptors regulate bouton Ca signalling and mossy fibre LTP. Sci Rep 2011; 1:103. [PMID: 22355621 PMCID: PMC3216588 DOI: 10.1038/srep00103] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2011] [Accepted: 09/07/2011] [Indexed: 12/04/2022] Open
Abstract
It is currently unknown why glutamatergic presynaptic terminals express multiple types of glutamate receptors. We have addressed this question by studying both acute and long-term regulation of mossy fibre function in the hippocampus. We find that inhibition of both mGlu1 and mGlu5 receptors together can block the induction of mossy fibre LTP. Furthermore, mossy fibre LTP can be induced by the pharmacological activation of either mGlu1 or mGlu5 receptors, provided that kainate receptors are also stimulated. Like conventional mossy fibre LTP, chemically-induced mossy fibre LTP (chem-LTPm) depends on Ca2+ release from intracellular stores and the activation of PKA. Similar synergistic interactions between mGlu receptors and kainate receptors were observed at the level of Ca2+ signalling in individual giant mossy fibre boutons. Thus three distinct glutamate receptors interact, in both an AND and OR gate fashion, to regulate both immediate and long-term presynaptic function in the brain.
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Affiliation(s)
- Robert Nisticò
- MRC Centre for Synaptic Plasticity, School of Physiology and Pharmacology, University of Bristol, Bristol, BS8 1TD, United Kingdom
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198
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Differential effect of the mGlu5 receptor positive allosteric modulator ADX-47273 on early and late hippocampal LTP. Neuropharmacology 2011; 61:707-14. [DOI: 10.1016/j.neuropharm.2011.05.014] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2010] [Revised: 02/28/2011] [Accepted: 05/17/2011] [Indexed: 11/23/2022]
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199
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Verpelli C, Dvoretskova E, Vicidomini C, Rossi F, Chiappalone M, Schoen M, Di Stefano B, Mantegazza R, Broccoli V, Böckers TM, Dityatev A, Sala C. Importance of Shank3 protein in regulating metabotropic glutamate receptor 5 (mGluR5) expression and signaling at synapses. J Biol Chem 2011; 286:34839-50. [PMID: 21795692 PMCID: PMC3186429 DOI: 10.1074/jbc.m111.258384] [Citation(s) in RCA: 152] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Shank3/PROSAP2 gene mutations are associated with cognitive impairment ranging from mental retardation to autism. Shank3 is a large scaffold postsynaptic density protein implicated in dendritic spines and synapse formation; however, its specific functions have not been clearly demonstrated. We have used RNAi to knockdown Shank3 expression in neuronal cultures and showed that this treatment specifically reduced the synaptic expression of the metabotropic glutamate receptor 5 (mGluR5), but did not affect the expression of other major synaptic proteins. The functional consequence of Shank3 RNAi knockdown was impaired signaling via mGluR5, as shown by reduction in ERK1/2 and CREB phosphorylation induced by stimulation with (S)-3,5-dihydroxyphenylglycine (DHPG) as the agonist of mGluR5 receptors, impaired mGluR5-dependent synaptic plasticity (DHPG-induced long-term depression), and impaired mGluR5-dependent modulation of neural network activity. We also found morphological abnormalities in the structure of synapses (spine number, width, and length) and impaired glutamatergic synaptic transmission, as shown by reduction in the frequency of miniature excitatory postsynaptic currents (mEPSC). Notably, pharmacological augmentation of mGluR5 activity using 3-cyano-N-(1,3-diphenyl-1H-pyrazol-5-yl)-benzamide as the positive allosteric modulator of these receptors restored mGluR5-dependent signaling (DHPG-induced phosphorylation of ERK1/2) and normalized the frequency of mEPSCs in Shank3-knocked down neurons. These data demonstrate that a deficit in mGluR5-mediated intracellular signaling in Shank3 knockdown neurons can be compensated by 3-cyano-N-(1,3-diphenyl-1H-pyrazol-5-yl)-benzamide; this raises the possibility that pharmacological augmentation of mGluR5 activity represents a possible new therapeutic approach for patients with Shank3 mutations.
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Affiliation(s)
- Chiara Verpelli
- Department of Pharmacology, CNR Institute of Neuroscience, University of Milan, Milan 20129, Italy
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200
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Tsvetkov EA, Suderevskaya EI, Vesselkin NP. Role of long-term potentiation in mechanism of the conditioned learning. J EVOL BIOCHEM PHYS+ 2011. [DOI: 10.1134/s0022093011030017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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