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Park EH, Kao HY, Jourdi H, van Dijk MT, Carrillo-Segura S, Tunnell KW, Gutierrez J, Wallace EJ, Troy-Regier M, Radwan B, Lesburguères E, Alarcon JM, Fenton AA. Phencyclidine Disrupts Neural Coordination and Cognitive Control by Dysregulating Translation. BIOLOGICAL PSYCHIATRY GLOBAL OPEN SCIENCE 2024; 4:252-263. [PMID: 38298788 PMCID: PMC10829677 DOI: 10.1016/j.bpsgos.2023.04.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2022] [Revised: 04/19/2023] [Accepted: 04/20/2023] [Indexed: 02/02/2024] Open
Abstract
Background Phencyclidine (PCP) causes psychosis, is abused with increasing frequency, and was extensively used in antipsychotic drug discovery. PCP discoordinates hippocampal ensemble action potential discharge and impairs cognitive control in rats, but how this uncompetitive NMDA receptor (NMDAR) antagonist impairs cognition remains unknown. Methods The effects of PCP were investigated on hippocampal CA1 ensemble action potential discharge in vivo in urethane-anesthetized rats and during awake behavior in mice, on synaptic responses in ex vivo mouse hippocampus slices, in mice on a hippocampus-dependent active place avoidance task that requires cognitive control, and on activating the molecular machinery of translation in acute hippocampus slices. Mechanistic causality was assessed by comparing the PCP effects with the effects of inhibitors of protein synthesis, group I metabotropic glutamate receptors (mGluR1/5), and subunit-selective NMDARs. Results Consistent with ionotropic actions, PCP discoordinated CA1 ensemble action potential discharge. PCP caused hyperactivity and impaired active place avoidance, despite the rodents having learned the task before PCP administration. Consistent with metabotropic actions, PCP exaggerated protein synthesis-dependent DHPG-induced mGluR1/5-stimulated long-term synaptic depression. Pretreatment with anisomycin or the mGluR1/5 antagonist MPEP, both of which repress translation, prevented PCP-induced discoordination and the cognitive and sensorimotor impairments. PCP as well as the NR2A-containing NMDAR antagonist NVP-AAM077 unbalanced translation that engages the Akt, mTOR (mechanistic target of rapamycin), and 4EBP1 translation machinery and increased protein synthesis, whereas the NR2B-containing antagonist Ro25-6981 did not. Conclusions PCP dysregulates translation, acting through NR2A-containing NMDAR subtypes, recruiting mGluR1/5 signaling pathways, and leading to neural discoordination that is central to the cognitive and sensorimotor impairments.
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Affiliation(s)
- Eun Hye Park
- Center for Neural Science, New York University, New York, New York
| | - Hsin-Yi Kao
- Center for Neural Science, New York University, New York, New York
| | - Hussam Jourdi
- Center for Neural Science, New York University, New York, New York
| | - Milenna T. van Dijk
- Center for Neural Science, New York University, New York, New York
- Graduate Program in Neuroscience and Physiology, New York University Langone Medical Center, New York, New York
| | - Simón Carrillo-Segura
- Center for Neural Science, New York University, New York, New York
- Graduate Program in Mechanical and Aerospace Engineering, New York University Tandon School of Engineering, New York, New York
| | - Kayla W. Tunnell
- Center for Neural Science, New York University, New York, New York
| | | | - Emma J. Wallace
- Graduate Program in Neural and Behavioral Science, State University of New York, Downstate Health Sciences University, Brooklyn, New York
- Department of Physiology and Pharmacology, State University of New York, Downstate Health Sciences University, Brooklyn, New York
| | - Matthew Troy-Regier
- Graduate Program in Neural and Behavioral Science, State University of New York, Downstate Health Sciences University, Brooklyn, New York
- Department of Physiology and Pharmacology, State University of New York, Downstate Health Sciences University, Brooklyn, New York
| | - Basma Radwan
- Graduate Program in Neural Science, Center for Neural Science, New York University, New York, New York
| | | | - Juan Marcos Alarcon
- Department of Pathology, State University of New York, Downstate Health Sciences University, Brooklyn, New York
- Robert F. Furchgott Center for Neural and Behavioral Science, State University of New York, Downstate Health Sciences University, Brooklyn, New York
| | - André A. Fenton
- Center for Neural Science, New York University, New York, New York
- Department of Physiology and Pharmacology, State University of New York, Downstate Health Sciences University, Brooklyn, New York
- Robert F. Furchgott Center for Neural and Behavioral Science, State University of New York, Downstate Health Sciences University, Brooklyn, New York
- Neuroscience Institute, NYU Langone Health, New York, New York
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2
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Hoglund BK, Carfagno V, Olive MF, Leyrer-Jackson JM. Metabotropic glutamate receptors and cognition: From underlying plasticity and neuroprotection to cognitive disorders and therapeutic targets. INTERNATIONAL REVIEW OF NEUROBIOLOGY 2023; 168:367-413. [PMID: 36868635 DOI: 10.1016/bs.irn.2022.10.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Metabotropic glutamate (mGlu) receptors are G protein-coupled receptors that play pivotal roles in mediating the activity of neurons and other cell types within the brain, communication between cell types, synaptic plasticity, and gene expression. As such, these receptors play an important role in a number of cognitive processes. In this chapter, we discuss the role of mGlu receptors in various forms of cognition and their underlying physiology, with an emphasis on cognitive dysfunction. Specifically, we highlight evidence that links mGlu physiology to cognitive dysfunction across brain disorders including Parkinson's disease, Alzheimer's disease, Fragile X syndrome, post-traumatic stress disorder, and schizophrenia. We also provide recent evidence demonstrating that mGlu receptors may elicit neuroprotective effects in particular disease states. Lastly, we discuss how mGlu receptors can be targeted utilizing positive and negative allosteric modulators as well as subtype specific agonists and antagonist to restore cognitive function across these disorders.
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Affiliation(s)
- Brandon K Hoglund
- Department of Medical Education, School of Medicine, Creighton University, Phoenix, AZ, United States
| | - Vincent Carfagno
- School of Medicine, Midwestern University, Glendale, AZ, United States
| | - M Foster Olive
- Department of Psychology, Arizona State University, Tempe, AZ, United States
| | - Jonna M Leyrer-Jackson
- Department of Medical Education, School of Medicine, Creighton University, Phoenix, AZ, United States.
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3
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Smart K, Worhunsky PD, Scheinost D, Angarita GA, Esterlis I, Carson RE, Krystal JH, O'Malley SS, Cosgrove KP, Hillmer AT. Multimodal neuroimaging of metabotropic glutamate 5 receptors and functional connectivity in alcohol use disorder. Alcohol Clin Exp Res 2022; 46:770-782. [PMID: 35342968 PMCID: PMC9117461 DOI: 10.1111/acer.14816] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2021] [Revised: 03/15/2022] [Accepted: 03/19/2022] [Indexed: 12/01/2022]
Abstract
BACKGROUND People recovering from alcohol use disorder (AUD) show altered resting brain connectivity. The metabotropic glutamate 5 (mGlu5) receptor is an important regulator of synaptic plasticity potentially linked with synchronized brain activity and a target of interest in treating AUD. The goal of this work was to assess potential relationships of brain connectivity at rest with mGlu5 receptor availability in people with AUD at two time points early in abstinence. METHODS Forty-eight image data sets were acquired with a multimodal neuroimaging battery that included resting-state functional magnetic resonance imaging (fMRI) and mGlu5 receptor positron emission tomography (PET) with the radiotracer [18 F]FPEB. Participants with AUD (n = 14) were scanned twice, at approximately 1 and 4 weeks after beginning supervised abstinence. [18 F]FPEB PET results were published previously. Primary comparisons of fMRI outcomes were performed between the AUD group and healthy controls (HCs; n = 23) and assessed changes over time within the AUD group. Relationships between resting-state connectivity measures and mGlu5 receptor availability were explored within groups. RESULTS Compared to HCs, global functional connectivity of the orbitofrontal cortex was higher in the AUD group at 4 weeks of abstinence (p = 0.003), while network-level functional connectivity within the default mode network (DMN) was lower (p < 0.04). Exploratory multimodal analyses showed that mGlu5 receptor availability was correlated with global connectivity across all brain regions (HCs, r = 0.41; AUD group at 1 week of abstinence, r = 0.50 and at 4 weeks, r = 0.46; all p < 0.0001). Furthermore, a component of cortical and striatal mGlu5 availability was correlated with connectivity between the DMN and salience networks in HCs (r = 0.60, p = 0.003) but not in the AUD group (p > 0.3). CONCLUSIONS These preliminary findings of altered global and network connectivity during the first month of abstinence from drinking may reflect the loss of efficient network function, while exploratory relationships with mGlu5 receptor availability suggest a potential glutamatergic relationship with network coherence.
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Affiliation(s)
- Kelly Smart
- Yale PET Center, Yale School of Medicine, New Haven, Connecticut, USA.,Department of Radiology and Biomedical Imaging, Yale School of Medicine, New Haven, Connecticut, USA
| | - Patrick D Worhunsky
- Department of Psychiatry, Yale School of Medicine, New Haven, Connecticut, USA
| | - Dustin Scheinost
- Department of Radiology and Biomedical Imaging, Yale School of Medicine, New Haven, Connecticut, USA.,Department of Biomedical Engineering, Yale School of Engineering & Applied Science, New Haven, Connecticut, USA
| | - Gustavo A Angarita
- Department of Psychiatry, Yale School of Medicine, New Haven, Connecticut, USA
| | - Irina Esterlis
- Department of Psychiatry, Yale School of Medicine, New Haven, Connecticut, USA
| | - Richard E Carson
- Yale PET Center, Yale School of Medicine, New Haven, Connecticut, USA.,Department of Radiology and Biomedical Imaging, Yale School of Medicine, New Haven, Connecticut, USA.,Department of Biomedical Engineering, Yale School of Engineering & Applied Science, New Haven, Connecticut, USA
| | - John H Krystal
- Department of Psychiatry, Yale School of Medicine, New Haven, Connecticut, USA
| | | | - Kelly P Cosgrove
- Department of Radiology and Biomedical Imaging, Yale School of Medicine, New Haven, Connecticut, USA.,Department of Psychiatry, Yale School of Medicine, New Haven, Connecticut, USA
| | - Ansel T Hillmer
- Yale PET Center, Yale School of Medicine, New Haven, Connecticut, USA.,Department of Radiology and Biomedical Imaging, Yale School of Medicine, New Haven, Connecticut, USA.,Department of Psychiatry, Yale School of Medicine, New Haven, Connecticut, USA.,Department of Biomedical Engineering, Yale School of Engineering & Applied Science, New Haven, Connecticut, USA
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4
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Teleuca AE, Alemà GS, Casolini P, Barberis I, Ciabattoni F, Orlando R, Di Menna L, Iacovelli L, Scioli MR, Nicoletti F, Zuena AR. Changes in mGlu5 Receptor Signaling Are Associated with Associative Learning and Memory Extinction in Mice. Life (Basel) 2022; 12:life12030463. [PMID: 35330215 PMCID: PMC8955168 DOI: 10.3390/life12030463] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2022] [Revised: 03/15/2022] [Accepted: 03/16/2022] [Indexed: 11/16/2022] Open
Abstract
Using an in vivo method for the assessment of polyphosphoinositide (PI) hydrolysis, we examine whether spatial learning and memory extinction cause changes in mGlu5 metabotropic glutamate receptor signaling in the hippocampus and prefrontal cortex. We use the following five groups of mice: (i) naive mice; (ii) control mice exposed to the same environment as learner mice; (iii) leaner mice, trained for four days in a water maze; (iv) mice in which memory extinction was induced by six trials without the platform; (v) mice that spontaneously lost memory. The mGlu5 receptor-mediated PI hydrolysis was significantly reduced in the dorsal hippocampus of learner mice as compared to naive and control mice. The mGlu5 receptor signaling was also reduced in the ventral hippocampus and prefrontal cortex of learner mice, but only with respect to naive mice. Memory extinction was associated with a large up-regulation of mGlu5 receptor-mediated PI hydrolysis in the three brain regions and with increases in mGlu5 receptor and phospholipase-Cβ protein levels in the ventral and dorsal hippocampus, respectively. These findings support a role for mGlu5 receptors in mechanisms underlying spatial learning and suggest that mGlu5 receptors are candidate drug targets for disorders in which cognitive functions are impaired or aversive memories are inappropriately retained.
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Affiliation(s)
- Ana Elena Teleuca
- Department of Physiology and Pharmacology, Sapienza University of Rome, 00185 Rome, Italy; (A.E.T.); (G.S.A.); (P.C.); (I.B.); (F.C.); (R.O.); (L.I.); (F.N.)
| | - Giovanni Sebastiano Alemà
- Department of Physiology and Pharmacology, Sapienza University of Rome, 00185 Rome, Italy; (A.E.T.); (G.S.A.); (P.C.); (I.B.); (F.C.); (R.O.); (L.I.); (F.N.)
| | - Paola Casolini
- Department of Physiology and Pharmacology, Sapienza University of Rome, 00185 Rome, Italy; (A.E.T.); (G.S.A.); (P.C.); (I.B.); (F.C.); (R.O.); (L.I.); (F.N.)
| | - Ilaria Barberis
- Department of Physiology and Pharmacology, Sapienza University of Rome, 00185 Rome, Italy; (A.E.T.); (G.S.A.); (P.C.); (I.B.); (F.C.); (R.O.); (L.I.); (F.N.)
| | - Francesco Ciabattoni
- Department of Physiology and Pharmacology, Sapienza University of Rome, 00185 Rome, Italy; (A.E.T.); (G.S.A.); (P.C.); (I.B.); (F.C.); (R.O.); (L.I.); (F.N.)
| | - Rosamaria Orlando
- Department of Physiology and Pharmacology, Sapienza University of Rome, 00185 Rome, Italy; (A.E.T.); (G.S.A.); (P.C.); (I.B.); (F.C.); (R.O.); (L.I.); (F.N.)
- IRCCS Neuromed, 86077 Pozzilli, Italy; (L.D.M.); (M.R.S.)
| | - Luisa Di Menna
- IRCCS Neuromed, 86077 Pozzilli, Italy; (L.D.M.); (M.R.S.)
| | - Luisa Iacovelli
- Department of Physiology and Pharmacology, Sapienza University of Rome, 00185 Rome, Italy; (A.E.T.); (G.S.A.); (P.C.); (I.B.); (F.C.); (R.O.); (L.I.); (F.N.)
| | | | - Ferdinando Nicoletti
- Department of Physiology and Pharmacology, Sapienza University of Rome, 00185 Rome, Italy; (A.E.T.); (G.S.A.); (P.C.); (I.B.); (F.C.); (R.O.); (L.I.); (F.N.)
- IRCCS Neuromed, 86077 Pozzilli, Italy; (L.D.M.); (M.R.S.)
| | - Anna Rita Zuena
- Department of Physiology and Pharmacology, Sapienza University of Rome, 00185 Rome, Italy; (A.E.T.); (G.S.A.); (P.C.); (I.B.); (F.C.); (R.O.); (L.I.); (F.N.)
- Correspondence: ; Tel./Fax: +39-06-49912513
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5
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Upregulation of the mGlu5 receptor and COX-2 protein in the mouse brain after imipramine and NS398, searching for mechanisms of regulation. Neurochem Int 2021; 150:105193. [PMID: 34571049 DOI: 10.1016/j.neuint.2021.105193] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2021] [Revised: 09/20/2021] [Accepted: 09/21/2021] [Indexed: 11/24/2022]
Abstract
Imipramine belongs to a group of tricyclic antidepressants (TCAs). It has been also documented that its antidepressant activity connects with the modulation of cytosolic phospholipase A2 (cPLA2) and arachidonic acid (AA) turnover. Through this mechanism, imipramine can indirectly modify glutamate (Glu) transmission. Additionally, it has been shown that chronic treatment with imipramine results in the upregulation of the metabotropic glutamate receptor subtype 5 (mGlu5 receptor) in the hippocampus of rats. Our previous study revealed that manipulation of the AA pathway via inhibition of cyclooxygenase-2 (COX-2) by selective COX-2 inhibitor (NS398) could effectively modulate the behavior of mice treated with imipramine. Here, we hypothesized that COX-2 inhibition could similarly to imipramine influence mGlu5 receptor, and thus NS398 can modulate the effect of imipramine on Glu. Moreover, such regulation changes should correspond with alterations in neurotransmission. Increased cPLA activity after imipramine administration may change the activity of the AA pathway and the endocannabinoid metabolism, e.g., 2-Arachidonyl-glycerol (2-AG). To verify the idea, mGlu5 receptor level was investigated in the hippocampus (HC) and prefrontal cortex (PFC) of mice treated for 7 or 14 days with imipramine and/or COX-2 inhibitor: NS398. Western blot and PCR analyses were conducted. Moreover, the excitatory (Glu) and inhibitory (gamma-aminobutyric acid; GABA) neurotransmitters were measured using HPLC and 2-AG using ELISA. A time-dependent change in mGlu5 receptor and COX-2 protein level, COX-2 expression, and 2-AG level in the PFC after imipramine administration was found. Up-regulation of mGlu5 receptor after NS398 was found in HC and PFC. A structure-dependent shift between excitatory vs. inhibitory transmission was detected when NS398 and imipramine were co-administered.
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6
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Mecca AP, Rogers K, Jacobs Z, McDonald JW, Michalak HR, DellaGioia N, Zhao W, Hillmer AT, Nabulsi N, Lim K, Ropchan J, Huang Y, Matuskey D, Esterlis I, Carson RE, van Dyck CH. Effect of age on brain metabotropic glutamate receptor subtype 5 measured with [ 18F]FPEB PET. Neuroimage 2021; 238:118217. [PMID: 34052464 PMCID: PMC8378132 DOI: 10.1016/j.neuroimage.2021.118217] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2020] [Revised: 04/08/2021] [Accepted: 05/26/2021] [Indexed: 12/31/2022] Open
Abstract
OBJECTIVE Metabotropic glutamate receptor subtype 5 (mGluR5) is integral to the brain glutamatergic system and cognitive function. This study investigated whether aging is associated with decreased brain mGluR5 availability. METHODS Cognitively normal participants (n = 45), aged 18 to 84 years, underwent [18F]FPEB positron emission tomography scans to quantify brain mGluR5. Distribution volume (VT) was computed using a venous or arterial input function and equilibrium modeling from 90 to 120 min. In the primary analysis, the association between age and VT in the hippocampus and association cortex was evaluated using a linear mixed model. Exploratory analyses assessed the association between age and VT in multiple brain regions. The contribution of gray matter tissue alterations and partial volume effects to associations with age was also examined. RESULTS In the primary analysis, older age was associated with lower [18F]FPEB binding to mGluR5 (P = 0.026), whereas this association was not significant after gray matter masking or partial volume correction to account for age-related tissue loss. Post hoc analyses revealed an age-related decline in mGluR5 availability in the hippocampus of 4.5% per decade (P = 0.007) and a non-significant trend in the association cortex (P = 0.085). An exploratory analysis of multiple brain regions revealed broader inverse associations of age with mGluR5 availability, but not after partial volume correction. CONCLUSION Reductions in mGluR5 availability with age appear to be largely mediated by tissue loss. Quantification of [18F]FPEB binding to mGluR5 may expand our understanding of age-related molecular changes and the relationship with brain tissue loss.
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Affiliation(s)
- Adam P Mecca
- Alzheimer's Disease Research Unit, Yale University School of Medicine, One Church Street, 8th Floor, New Haven, CT, 06514, USA; Department of Psychiatry, Yale University School of Medicine, New Haven, CT, USA.
| | - Kelly Rogers
- Alzheimer's Disease Research Unit, Yale University School of Medicine, One Church Street, 8th Floor, New Haven, CT, 06514, USA; Department of Psychiatry, Yale University School of Medicine, New Haven, CT, USA
| | - Zachary Jacobs
- Alzheimer's Disease Research Unit, Yale University School of Medicine, One Church Street, 8th Floor, New Haven, CT, 06514, USA; Department of Psychiatry, Yale University School of Medicine, New Haven, CT, USA
| | - Julia W McDonald
- Alzheimer's Disease Research Unit, Yale University School of Medicine, One Church Street, 8th Floor, New Haven, CT, 06514, USA; Department of Psychiatry, Yale University School of Medicine, New Haven, CT, USA
| | - Hannah R Michalak
- Alzheimer's Disease Research Unit, Yale University School of Medicine, One Church Street, 8th Floor, New Haven, CT, 06514, USA; Department of Psychiatry, Yale University School of Medicine, New Haven, CT, USA
| | - Nicole DellaGioia
- Department of Psychiatry, Yale University School of Medicine, New Haven, CT, USA
| | - Wenzhen Zhao
- Alzheimer's Disease Research Unit, Yale University School of Medicine, One Church Street, 8th Floor, New Haven, CT, 06514, USA; Department of Psychiatry, Yale University School of Medicine, New Haven, CT, USA
| | - Ansel T Hillmer
- Department of Psychiatry, Yale University School of Medicine, New Haven, CT, USA; Department of Radiology and Biomedical Imaging, Yale University School of Medicine, New Haven, CT, USA
| | - Nabeel Nabulsi
- Department of Radiology and Biomedical Imaging, Yale University School of Medicine, New Haven, CT, USA
| | - Keunpoong Lim
- Department of Radiology and Biomedical Imaging, Yale University School of Medicine, New Haven, CT, USA
| | - Jim Ropchan
- Department of Radiology and Biomedical Imaging, Yale University School of Medicine, New Haven, CT, USA
| | - Yiyun Huang
- Department of Radiology and Biomedical Imaging, Yale University School of Medicine, New Haven, CT, USA
| | - David Matuskey
- Department of Psychiatry, Yale University School of Medicine, New Haven, CT, USA; Department of Radiology and Biomedical Imaging, Yale University School of Medicine, New Haven, CT, USA; Department of Neurology, Yale University School of Medicine, New Haven, CT, USA
| | - Irina Esterlis
- Department of Psychiatry, Yale University School of Medicine, New Haven, CT, USA
| | - Richard E Carson
- Department of Radiology and Biomedical Imaging, Yale University School of Medicine, New Haven, CT, USA
| | - Christopher H van Dyck
- Alzheimer's Disease Research Unit, Yale University School of Medicine, One Church Street, 8th Floor, New Haven, CT, 06514, USA; Department of Psychiatry, Yale University School of Medicine, New Haven, CT, USA; Department of Neuroscience, Yale University School of Medicine, New Haven, CT, USA; Department of Neurology, Yale University School of Medicine, New Haven, CT, USA
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7
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Xu J, Marshall JJ, Kraniotis S, Nomura T, Zhu Y, Contractor A. Genetic disruption of Grm5 causes complex alterations in motor activity, anxiety and social behaviors. Behav Brain Res 2021; 411:113378. [PMID: 34029630 DOI: 10.1016/j.bbr.2021.113378] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2021] [Revised: 05/11/2021] [Accepted: 05/19/2021] [Indexed: 12/14/2022]
Abstract
Autism is a neurodevelopmental disorder characterized by impaired social interactions and restricted and repetitive behaviors. Although group 1 metabotropic glutamate receptors (mGluRs), and in particular mGluR5, have been extensively proposed as potential targets for intervention in autism and other neurodevelopmental disorders, there has not been a comprehensive analysis of the effect of mGluR5 loss on behaviors typically assessed in autism mouse models thought to be correlates of behavioral symptoms of human disorders. Here we present a behavioral characterization of mice with complete or partial loss of mGluR5 (homozygous or heterozygous null mutations in Grm5 gene). We tested several autism related behaviors including social interaction, repetitive grooming, digging and locomotor behaviors. We found that digging and marble burying behaviors were almost completely abolished in mGluR5 ko mice, although self-grooming was not altered. Social interaction was impaired in ko but not in heterozygote (het) mice. In tests of locomotor activity and anxiety related behaviors, mGluR5 ko mice exhibited hyperactivity and reduced anxiety in the open field test but unexpectedly, showed hypoactivity in the elevated zero-maze test. There was no impairment in motor learning in the accelerating rotarod in both ko and het mutant. Together these results provide support for the importance of mGluR5 in motor and social behaviors that are specifically affected in autism disorders.
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Affiliation(s)
- Jian Xu
- Department of Physiology, Northwestern University Feinberg School of Medicine, United States.
| | - John J Marshall
- Department of Physiology, Northwestern University Feinberg School of Medicine, United States
| | - Stephen Kraniotis
- Department of Physiology, Northwestern University Feinberg School of Medicine, United States
| | - Toshihiro Nomura
- Department of Physiology, Northwestern University Feinberg School of Medicine, United States
| | - Yongling Zhu
- Department of Physiology, Northwestern University Feinberg School of Medicine, United States
| | - Anis Contractor
- Department of Physiology, Northwestern University Feinberg School of Medicine, United States; Department of Neurobiology, Weinberg College of Arts and Sciences, Northwestern University, Chicago, IL, 60611, United States.
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8
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Stachowicz K, Sowa-Kućma M, Pańczyszyn-Trzewik P, Misztak P, Marciniak M, Bobula B, Tokarski K. Behavioral consequences of co-administration of MTEP and the COX-2 inhibitor NS398 in mice. Part 2. Neurosci Lett 2021; 741:135435. [PMID: 33171212 DOI: 10.1016/j.neulet.2020.135435] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2020] [Revised: 09/14/2020] [Accepted: 10/06/2020] [Indexed: 11/22/2022]
Abstract
Our earlier study demonstrated, that antidepressant-like and also cognitive action of MTEP, a metabotropic glutamate receptor subtype 5 (mGluR5) antagonist, was influenced by cyclooxygenase-2 (COX-2) inhibition in mice. We detected a decrease in the mGluR7 protein level in the hippocampus (HC) of mice co-treated chronically with MTEP and NS398 (a COX-2 inhibitor). We found both antidepressant-like effects and cognitive to be associated with mGlu7 receptor-mediated mechanisms.
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Affiliation(s)
- Katarzyna Stachowicz
- Department of Neurobiology, Maj Institute of Pharmacology, Polish Academy of Sciences, Smętna 12, 31-343, Kraków, Poland.
| | - Magdalena Sowa-Kućma
- Department of Human Physiology, Medical College of Rzeszów University, Institute of Medical Science, 35-310, Rzeszow, Kopisto Street 2a, Poland
| | - Patrycja Pańczyszyn-Trzewik
- Department of Neurobiology, Maj Institute of Pharmacology, Polish Academy of Sciences, Smętna 12, 31-343, Kraków, Poland; Department of Human Physiology, Medical College of Rzeszów University, Institute of Medical Science, 35-310, Rzeszow, Kopisto Street 2a, Poland
| | - Paulina Misztak
- Department of Neurobiology, Maj Institute of Pharmacology, Polish Academy of Sciences, Smętna 12, 31-343, Kraków, Poland; Jagiellonian University Medical College, Kraków, Poland
| | - Marcin Marciniak
- Department of Neurobiology, Maj Institute of Pharmacology, Polish Academy of Sciences, Smętna 12, 31-343, Kraków, Poland
| | - Bartosz Bobula
- Department of Physiology, Maj Institute of Pharmacology, Polish Academy of Sciences, Smętna 12, 31-343, Kraków, Poland
| | - Krzysztof Tokarski
- Department of Physiology, Maj Institute of Pharmacology, Polish Academy of Sciences, Smętna 12, 31-343, Kraków, Poland
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9
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Wang HY, MacDonald ML, Borgmann-Winter KE, Banerjee A, Sleiman P, Tom A, Khan A, Lee KC, Roussos P, Siegel SJ, Hemby SE, Bilker WB, Gur RE, Hahn CG. mGluR5 hypofunction is integral to glutamatergic dysregulation in schizophrenia. Mol Psychiatry 2020; 25:750-760. [PMID: 30214040 PMCID: PMC7500805 DOI: 10.1038/s41380-018-0234-y] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/25/2018] [Revised: 06/18/2018] [Accepted: 07/09/2018] [Indexed: 11/19/2022]
Abstract
Multiple lines of evidence point to glutamatergic signaling in the postsynaptic density (PSD) as a pathophysiologic mechanism in schizophrenia. Integral to PSD glutamatergic signaling is reciprocal interplay between GluN and mGluR5 signaling. We examined agonist-induced mGluR5 signaling in the postmortem dorsolateral prefrontal cortex (DLPFC) derived from 17 patients and age-matched and sex-matched controls. The patient group showed a striking reduction in mGluR5 signaling, manifested by decreases in Gq/11 coupling and association with PI3K and Homer compared to controls (p < 0.01 for all). This was accompanied by increases in serine and tyrosine phosphorylation of mGluR5, which can decrease mGluR5 activity via desensitization (p < 0.01). In addition, we find altered protein-protein interaction (PPI) of mGluR5 with RGS4, norbin, Preso 1 and tamalin, which can also attenuate mGluR5 activity. We previously reported molecular underpinnings of GluN hypofunction (decreased GluN2 phosphorylation) and here we show those of reduced mGluR5 signaling in schizophrenia. We find that reduced GluN2 phosphorylation can be precipitated by attenuated mGluR5 activity and that increased mGluR5 phosphorylation can result from decreased GluN function, suggesting a reciprocal interplay between the two pathways in schizophrenia. Interestingly, the patient group showed decreased mGluR5-GluN association (p < 0.01), a mechanistic basis for the reciprocal facilitation. In sum, we present the first direct evidence for mGluR5 hypoactivity, propose a reciprocal interplay between GluN and mGluR5 pathways as integral to glutamatergic dysregulation and suggest protein-protein interactions in mGluR5-GluN complexes as potential targets for intervention in schizophrenia.
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Affiliation(s)
- Hoau-Yan Wang
- Department of Physiology, Pharmacology and Neuroscience, City University of New York School of Medicine, New York, NY 10031,Department of Biology and Neuroscience, Graduate School of the City University of New York, NY 10016
| | - Mathew L. MacDonald
- Department of Psychiatry, University of Pennsylvania, Philadelphia, PA 19104-3403
| | - Karin E. Borgmann-Winter
- Department of Psychiatry, University of Pennsylvania, Philadelphia, PA 19104-3403,Department of Child and Adolescent Psychiatry and Behavioral Sciences, Children’s Hospital of Philadelphia, Philadelphia, PA 19104
| | - Anamika Banerjee
- Department of Psychiatry, University of Pennsylvania, Philadelphia, PA 19104-3403
| | - Patrick Sleiman
- The Center for Applied Genomics, The Children’s Hospital of Philadelphia, and Department of Pediatrics, University of Pennsylvania School of Medicine, Philadelphia, PA, 19104
| | - Andrew Tom
- Department of Physiology, Pharmacology and Neuroscience, City University of New York School of Medicine, New York, NY 10031
| | - Amber Khan
- Department of Physiology, Pharmacology and Neuroscience, City University of New York School of Medicine, New York, NY 10031,Department of Biology and Neuroscience, Graduate School of the City University of New York, NY 10016
| | - Kuo-Chieh Lee
- Department of Physiology, Pharmacology and Neuroscience, City University of New York School of Medicine, New York, NY 10031
| | - Panos Roussos
- Department of Psychiatry, Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, 10029
| | - Steven J. Siegel
- Department of Psychiatry and the Behavioral Sciences, University of Southern California, Los Angeles, CA, 90007
| | - Scott E Hemby
- Department of Basic Pharmaceutical Sciences, High Point University, High Point, NC, 27106
| | - Warren B. Bilker
- Department of Biostatistics and Epidemiology, University of Pennsylvania, Philadelphia, PA 19104
| | - Raquel E. Gur
- Department of Psychiatry, University of Pennsylvania, Philadelphia, PA 19104-3403
| | - Chang-Gyu Hahn
- Department of Psychiatry, University of Pennsylvania, Philadelphia, PA, 19104-3403, USA.
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10
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Gregory KJ, Bridges TM, Gogliotti RG, Stauffer SR, Noetzel MJ, Jones CK, Lindsley CW, Conn PJ, Niswender CM. In Vitro to in Vivo Translation of Allosteric Modulator Concentration-Effect Relationships: Implications for Drug Discovery. ACS Pharmacol Transl Sci 2019; 2:442-452. [PMID: 32259076 DOI: 10.1021/acsptsci.9b00062] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2019] [Indexed: 12/15/2022]
Abstract
Allosteric modulation of GPCRs represents an increasingly explored approach in drug development. Due to complex pharmacology, however, the relationship(s) between modulator properties determined in vitro with in vivo concentration-effect phenomena is frequently unclear. We investigated key pharmacological properties of a set of metabotropic glutamate receptor 5 (mGlu5) positive allosteric modulators (PAMs) and their relevance to in vivo concentration-response relationships. These studies identified a significant relationship between in vitro PAM cooperativity (αβ), as well as the maximal response obtained from a simple in vitro PAM concentration-response experiment, with in vivo efficacy for reversal of amphetamine-induced hyperlocomotion. This correlation did not exist with PAM potency or affinity. Data across PAMs were then converged to calculate an in vivo concentration of glutamate putatively relevant to the mGlu5 PAM mechanism of action. This work demonstrates the ability to merge in vitro pharmacology profiles with relevant behavioral outcomes and also provides a novel method to estimate neurotransmitter concentrations in vivo.
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Affiliation(s)
- Karen J Gregory
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences and Department of Pharmacology, Monash University, Parkville, Victoria 3052, Australia
| | - Thomas M Bridges
- Department of Pharmacology and Vanderbilt Center for Neuroscience Drug Discovery, Vanderbilt University, Nashville, Tennessee 37232, United States
| | - Rocco G Gogliotti
- Department of Pharmacology and Vanderbilt Center for Neuroscience Drug Discovery, Vanderbilt University, Nashville, Tennessee 37232, United States
| | - Shaun R Stauffer
- Department of Pharmacology and Vanderbilt Center for Neuroscience Drug Discovery, Vanderbilt University, Nashville, Tennessee 37232, United States
| | - Meredith J Noetzel
- Department of Pharmacology and Vanderbilt Center for Neuroscience Drug Discovery, Vanderbilt University, Nashville, Tennessee 37232, United States
| | - Carrie K Jones
- Department of Pharmacology and Vanderbilt Center for Neuroscience Drug Discovery, Vanderbilt University, Nashville, Tennessee 37232, United States
| | - Craig W Lindsley
- Department of Pharmacology and Vanderbilt Center for Neuroscience Drug Discovery, Vanderbilt University, Nashville, Tennessee 37232, United States.,Departments of Chemistry and Biochemistry, Vanderbilt University, Nashville, Tennessee 37232, United States.,Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, Tennessee 37232, United States
| | - P Jeffrey Conn
- Department of Pharmacology and Vanderbilt Center for Neuroscience Drug Discovery, Vanderbilt University, Nashville, Tennessee 37232, United States.,Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, Tennessee 37232, United States.,Vanderbilt Kennedy Center, Vanderbilt University Medical Center, Nashville, Tennessee 37232, United States
| | - Colleen M Niswender
- Department of Pharmacology and Vanderbilt Center for Neuroscience Drug Discovery, Vanderbilt University, Nashville, Tennessee 37232, United States.,Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, Tennessee 37232, United States.,Vanderbilt Kennedy Center, Vanderbilt University Medical Center, Nashville, Tennessee 37232, United States
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11
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Behavioral consequences of co-administration of MTEP and the COX-2 inhibitor NS398 in mice. Part 1. Behav Brain Res 2019; 370:111961. [DOI: 10.1016/j.bbr.2019.111961] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2018] [Revised: 05/16/2019] [Accepted: 05/17/2019] [Indexed: 01/01/2023]
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12
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Nagayach A, Singh A, Geller AI. Separate Gene Transfers into Pre- and Postsynaptic Neocortical Neurons Connected by mGluR5-Containing Synapses. J Mol Neurosci 2019; 68:549-564. [PMID: 30972540 PMCID: PMC6615967 DOI: 10.1007/s12031-019-01317-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2018] [Accepted: 03/28/2019] [Indexed: 11/25/2022]
Abstract
mGluR5-containing synapses have essential roles in synaptic plasticity, circuit physiology, and learning, and dysfunction at these synapses is implicated in specific neurological disorders. As mGluR5-containing synapses are embedded in large and complex distributed circuits containing many neuron and synapse types, it is challenging to elucidate the roles of these synapses and to develop treatments for the associated disorders. Thus, it would be advantageous to deliver different genes into pre- and postsynaptic neurons connected by a mGluR5-containing synapse. Here, we develop this capability: The first gene transfer, into the presynaptic neurons, uses standard techniques to deliver a vector that expresses a synthetic peptide neurotransmitter. This peptide neurotransmitter has three domains: a dense core vesicle sorting domain, a mGluR5-binding domain composed of a single-chain variable fragment anti-mGluR5, and the His tag. Upon release, this peptide neurotransmitter binds to mGluR5, predominately located on the postsynaptic neurons. Selective gene transfer into these neurons uses antibody-mediated, targeted gene transfer and anti-His tag antibodies, as the synthetic peptide neurotransmitter contains the His tag. For the model system, we studied the connection between neurons in two neocortical areas: postrhinal and perirhinal cortices. Targeted gene transfer was over 80% specific for mGluR5-containing synapses, but untargeted gene transfer was only ~ 15% specific for these synapses. This technology may enable studies on the roles of mGluR5-containing neurons and synapses in circuit physiology and learning and support gene therapy treatments for specific disorders that involve dysfunction at these synapses.
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Affiliation(s)
- Aarti Nagayach
- Department of Ophthalmology, Louisiana State University Health Sciences Center, New Orleans, USA
| | - Anshuman Singh
- Department of Ophthalmology, Louisiana State University Health Sciences Center, New Orleans, USA
| | - Alfred I Geller
- Department of Ophthalmology, Louisiana State University Health Sciences Center, New Orleans, USA.
- Department of Pharmacology, Louisiana State University Health Sciences Center, New Orleans, USA.
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13
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Gobin C, Shallcross J, Schwendt M. Neurobiological substrates of persistent working memory deficits and cocaine-seeking in the prelimbic cortex of rats with a history of extended access to cocaine self-administration. Neurobiol Learn Mem 2019; 161:92-105. [PMID: 30946882 DOI: 10.1016/j.nlm.2019.03.007] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2018] [Revised: 02/21/2019] [Accepted: 03/26/2019] [Indexed: 01/16/2023]
Abstract
Cocaine use disorder (CUD) is associated with prefrontal cortex dysfunction and cognitive deficits that may contribute to persistent relapse susceptibility. As the relationship between cognitive deficits, cortical abnormalities and drug seeking is poorly understood, development of relevant animal models is of high clinical importance. Here, we used an animal model to characterize working memory and reversal learning in rats with a history of extended access cocaine self-administration and prolonged abstinence. We also investigated immediate and long-term functional changes within the prelimbic cortex (PrL) in relation to cognitive performance and drug-seeking. Adult male rats underwent 6 days of short-access (1 h/day) followed by 12 days of long-access (6 h/day) cocaine self-administration, or received passive saline infusions. Next, rats were tested in delayed match-to-sample (DMS) and (non)match-to-sample (NMS) tasks, and finally in a single context + cue relapse test on day 90 of abstinence. We found that a history of chronic cocaine self-administration impaired working memory, though sparing reversal learning, and that the components of these cognitive measures correlated with later drug-seeking. Further, we found that dysregulated metabolic activity and mGlu5 receptor signaling in the PrL of cocaine rats correlated with past working memory performance and/or drug-seeking, as indicated by the analysis of cytochrome oxidase reactivity, mGlu5 and Homer 1b/c protein expression, as well as Arc mRNA expression in mGlu5-positive cells. These findings advocate for a persistent post-cocaine PrL dysfunction, rooted in ineffective compensatory changes and manifested as impaired working memory performance and hyperreactivity to cocaine cues. Considering the possible interplay between the neural correlates underlying post-cocaine cognitive deficits and drug-seeking, cognitive function should be evaluated and considered when developing neurobiologically-based treatments of cocaine relapse.
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Affiliation(s)
- Christina Gobin
- Psychology Department, University of Florida, Gainesville, FL 32611, USA; Center for Addiction Research and Education (CARE) at University of Florida, USA
| | - John Shallcross
- Psychology Department, University of Florida, Gainesville, FL 32611, USA; Center for Addiction Research and Education (CARE) at University of Florida, USA
| | - Marek Schwendt
- Psychology Department, University of Florida, Gainesville, FL 32611, USA; Center for Addiction Research and Education (CARE) at University of Florida, USA.
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14
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Ramos-Prats A, Kölldorfer J, Paolo E, Zeidler M, Schmid G, Ferraguti F. An Appraisal of the Influence of the Metabotropic Glutamate 5 (mGlu5) Receptor on Sociability and Anxiety. Front Mol Neurosci 2019; 12:30. [PMID: 30873001 PMCID: PMC6401637 DOI: 10.3389/fnmol.2019.00030] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2018] [Accepted: 01/24/2019] [Indexed: 02/04/2023] Open
Abstract
Amongst the many neurotransmitter systems causally linked to the expression of social behavior, glutamate appears to play a pivotal role. In particular, metabotropic glutamate 5 (mGlu5) receptors have received much attention as its altered function has been reported in several mouse models of autism spectrum disorders and mental retardation. Inhibition of the activity of mGlu5 receptors by means of genetic or pharmacological manipulations improved social deficits in some of these animal models. However, in normal wild-type (WT) mice, pharmacological blockade of mGlu5 receptors yielded inconsistent results. The aim of our study was to investigate the actual contribution of decreased or absent mGlu5 receptor function in sociability and anxiety-like behavior as well as to explore the impact of mGlu5 receptor ablation on the pattern of brain activation upon social exposure. Here we show that Grm5-/- mice display higher social preference indexes compared to age-matched WT mice in the three-chambered social task. However, this effect was accompanied by a decreased exploratory activity during the test and increased anxiety-like behavior. Contrary to mGlu5 receptor ablation, the mGlu5 receptor negative allosteric modulator 3-((2-methyl-1,4-thiazolyl)ethynyl)pyridine (MTEP) induced anxiolytic effects without affecting social preference in WT mice. By mapping c-Fos expression in 21 different brain regions known to be involved in social interaction, we detected a specific activation of the prefrontal cortex and dorsolateral septum in Grm5-/- mice following social interaction. C-Fos expression correlation-based network and graph theoretical analyses further suggested dysfunctional connectivity and disruption of the functional brain network generated during social interaction in Grm5-/- mice. The lack of mGlu5 receptors resulted in profound rearrangements of the functional impact of prefrontal and hippocampal regions in the social interaction network. In conclusion, this work reveals a complex contribution of mGlu5 receptors in sociability and anxiety and points to the importance of these receptors in regulating brain functional connectivity during social interaction.
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Affiliation(s)
- Arnau Ramos-Prats
- Department of Pharmacology, Medical University of Innsbruck, Innsbruck, Austria
| | - Julia Kölldorfer
- Department of Pharmacology, Medical University of Innsbruck, Innsbruck, Austria
| | - Elena Paolo
- Department of Pharmacology, Medical University of Innsbruck, Innsbruck, Austria
| | - Maximilian Zeidler
- Department of Pharmacology, Medical University of Innsbruck, Innsbruck, Austria
| | - Gabriele Schmid
- Department of Pharmacology, Medical University of Innsbruck, Innsbruck, Austria
| | - Francesco Ferraguti
- Department of Pharmacology, Medical University of Innsbruck, Innsbruck, Austria
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15
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Huang M, Luo L, Zhang Y, Wang W, Dong J, Du W, Jiang W, Xu T. Metabotropic glutamate receptor 5 signalling induced NMDA receptor subunits alterations during the development of morphine-induced antinociceptive tolerance in mouse cortex. Biomed Pharmacother 2019; 110:717-726. [DOI: 10.1016/j.biopha.2018.12.042] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2018] [Revised: 12/06/2018] [Accepted: 12/07/2018] [Indexed: 11/25/2022] Open
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16
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Spampinato SF, Copani A, Nicoletti F, Sortino MA, Caraci F. Metabotropic Glutamate Receptors in Glial Cells: A New Potential Target for Neuroprotection? Front Mol Neurosci 2018; 11:414. [PMID: 30483053 PMCID: PMC6243036 DOI: 10.3389/fnmol.2018.00414] [Citation(s) in RCA: 61] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2018] [Accepted: 10/25/2018] [Indexed: 12/14/2022] Open
Abstract
Neurodegenerative disorders are characterized by excitotoxicity and neuroinflammation that finally lead to slow neuronal degeneration and death. Although neurons are the principal target, glial cells are important players as they contribute by either exacerbating or dampening the events that lead to neuroinflammation and neuronal damage. A dysfunction of the glutamatergic system is a common event in the pathophysiology of these diseases. Metabotropic glutamate (mGlu) receptors belong to a large family of G protein-coupled receptors largely expressed in neurons as well as in glial cells. They often appear overexpressed in areas involved in neurodegeneration, where they can modulate glutamatergic transmission. Of note, mGlu receptor upregulation may involve microglia or, even more frequently, astrocytes, where their activation causes release of factors potentially able to influence neuronal death. The expression of mGlu receptors has been also reported on oligodendrocytes, a glial cell type specifically involved in the development of multiple sclerosis. Here we will provide a general overview on the possible involvement of mGlu receptors expressed on glial cells in the pathogenesis of different neurodegenerative disorders and the potential use of subtype-selective mGlu receptor ligands as candidate drugs for the treatment of neurodegenerative disorders. Negative allosteric modulators (NAM) of mGlu5 receptors might represent a relevant pharmacological tool to develop new neuroprotective strategies in these diseases. Recent evidence suggests that targeting astrocytes and microglia with positive allosteric modulators (PAM) of mGlu3 receptor or oligodendrocytes with mGlu4 PAMS might represent novel pharmacological approaches for the treatment of neurodegenerative disorders.
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Affiliation(s)
| | - Agata Copani
- Department of Drug Sciences, University of Catania, Catania, Italy.,Institute of Biostructure and Bioimaging, National Research Council, Catania, Italy
| | - Ferdinando Nicoletti
- Department of Physiology and Pharmacology, Sapienza University of Rome, Rome, Italy.,Neuromed, Istituto di Ricovero e Cura a Carattere Scientifico, Pozzilli, Italy
| | - Maria Angela Sortino
- Department of Biomedical and Biotechnological Sciences, University of Catania, Catania, Italy
| | - Filippo Caraci
- Department of Drug Sciences, University of Catania, Catania, Italy.,Oasi Research Institute, Istituto di Ricovero e Cura a Carattere Scientifico, Troina, Italy
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17
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Neurotransmitter- and Release-Mode-Specific Modulation of Inhibitory Transmission by Group I Metabotropic Glutamate Receptors in Central Auditory Neurons of the Mouse. J Neurosci 2018; 38:8187-8199. [PMID: 30093538 DOI: 10.1523/jneurosci.0603-18.2018] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2018] [Revised: 06/27/2018] [Accepted: 07/27/2018] [Indexed: 12/21/2022] Open
Abstract
Neuromodulation mediated by metabotropic glutamate receptors (mGluRs) regulates many brain functions. However, the functions of mGluRs in the auditory system under normal and diseased states are not well understood. The medial nucleus of the trapezoid body (MNTB) is a critical nucleus in the auditory brainstem nuclei involved in sound localization. In addition to the classical calyx excitatory inputs, MNTB neurons also receive synaptic inhibition and it remains entirely unknown how this inhibition is regulated. Here, using whole-cell voltage clamp in brain slices, we investigated group I mGluR (mGluR I)-mediated modulation of the glycinergic and GABAergic inputs to MNTB neurons in both WT mice and a fragile X syndrome (FXS) mouse model (both sexes) in which the fragile X mental retardation gene 1 is knocked out (Fmr1 KO), causing exaggerated activity of mGluR I and behavioral phenotypes. Activation of mGluR I by (RS)-3,5-dihydroxyphenylglycine (3,5-DHPG) increased the frequency and amplitude of glycinergic spontaneous IPSCs (sIPSCs) in both WT and Fmr1 KO neurons in a voltage-gated sodium channel-dependent fashion, but did not modulate glycinergic evoked IPSCs (eIPSCs). In contrast, 3,5-DHPG did not affect GABAergic sIPSCs, but did suppress eIPSCs in WT neurons via endocannabinoid signaling. In the KO, the effect of 3,5-DHPG on GABAergic eIPSCs was highly variable, which supports the notion of impaired GABAergic signaling in the FXS model. The differential modulation of sIPSC and eIPSC and differential modulation of glycinergic and GABAergic transmission suggest distinct mechanisms responsible for spontaneous and evoked release of inhibitory transmitters and their modulation through the mGluR I signaling pathway.SIGNIFICANCE STATEMENT Neurons communicate with each other through the release of neurotransmitters, which assumes two basic modes, spontaneous and evoked release. These two release modes are believed to function using the same vesicle pool and machinery. Recent works have challenged this dogma, pointing to distinct vesicle release mechanisms underlying the two release modes. Here, we provide the first evidence in the central auditory system supporting this novel concept. We discovered neural-transmitter- and release-mode-specific neuromodulation of inhibitory transmission by metabotropic glutamate receptors and revealed part of the signaling pathways underlying this differential modulation. The results establish the foundation for a multitude of directions to study physiological significance of different release modes in auditory processing.
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18
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Barnes SA, Sheffler DJ, Semenova S, Cosford NDP, Bespalov A. Metabotropic Glutamate Receptor 5 as a Target for the Treatment of Depression and Smoking: Robust Preclinical Data but Inconclusive Clinical Efficacy. Biol Psychiatry 2018; 83:955-962. [PMID: 29628194 PMCID: PMC5953810 DOI: 10.1016/j.biopsych.2018.03.001] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/02/2017] [Revised: 03/02/2018] [Accepted: 03/05/2018] [Indexed: 12/11/2022]
Abstract
The ability of novel pharmacological compounds to improve outcomes in preclinical models is often not translated into clinical efficacy. Psychiatric disorders do not have biological boundaries, and identifying mechanisms to improve the translational bottleneck between preclinical and clinical research domains is an important and challenging task. Glutamate transmission is disrupted in several neuropsychiatric disorders. Metabotropic glutamate (mGlu) receptors represent a diverse class of receptors that contribute to excitatory neurotransmission. Given the wide, yet region-specific manner of expression, developing pharmacological compounds to modulate mGlu receptor activity provides an opportunity to subtly and selectively modulate excitatory neurotransmission. This review focuses on the potential involvement of mGlu5 receptor disruption in major depressive disorder and substance and/or alcohol use disorders. We provide an overview of the justification of targeting mGlu5 receptors in the treatment of these disorders, summarize the preclinical evidence for negatively modulating mGlu5 receptors as a therapeutic target for major depressive disorders and nicotine dependence, and highlight the outcomes of recent clinical trials. While the evidence of mGlu5 receptor negative allosteric modulation has been promising in preclinical investigations, these beneficial effects have not translated into clinical efficacy. In this review, we identify key challenges that may contribute to poor clinical translation and provide suggested approaches moving forward to potentially improve the translation from preclinical to clinical domains. Such approaches may increase the success of clinical trials and may reduce the translational bottleneck that exists in drug discovery for psychiatric disorders.
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Affiliation(s)
- Samuel A. Barnes
- Department of Psychiatry, University of California San Diego, 9500 Gilman Drive MC 0603, La Jolla, CA 92093, USA
| | - Douglas J. Sheffler
- NCI-Designated Cancer Center, Sanford Burnham Prebys Medical Discovery Institute, 10901 North Torrey Pines Road, La Jolla, CA, 92037, USA
| | - Svetlana Semenova
- Department of Psychiatry, University of California San Diego, 9500 Gilman Drive MC 0603, La Jolla, CA 92093, USA,PAREXEL International, 1560 E Chevy Chase Dr, suite 140, Glendale, CA 91206, USA
| | - Nicholas D. P. Cosford
- NCI-Designated Cancer Center, Sanford Burnham Prebys Medical Discovery Institute, 10901 North Torrey Pines Road, La Jolla, CA, 92037, USA
| | - Anton Bespalov
- EXCIVA, Heidelberg, Germany; Valdman Institute of Pharmacology, Pavlov Medical University, St. Petersburg, Russia.
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19
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Gupta I, Young AMJ. Metabotropic glutamate receptor modulation of dopamine release in the nucleus accumbens shell is unaffected by phencyclidine pretreatment: In vitro assessment using fast-scan cyclic voltammetry rat brain slices. Brain Res 2018. [PMID: 29524437 DOI: 10.1016/j.brainres.2018.03.007] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
The non-competitive glutamate antagonist, phencyclidine is used in rodents to model behavioural deficits see in schizophrenia. Importantly, these deficits endure long after the cessation of short-term chronic treatment (sub-chronic), indicating that the drug treatment causes long-term changes in the physiology and/or chemistry of the brain. There is evidence that this may occur through glutamatergic modulation of mesolimbic dopamine release, perhaps involving metabotropic glutamate receptors (mGluR). This study sought to investigate the effect of sub-chronic phencyclidine pretreatment on modulation of dopamine neurotransmission by metabotropic glutamate receptors 2 and 5 (mGluR2 and mGluR5) in the nucleus accumbens shell in vitro, with the hypothesis that phencyclidine pretreatment would disrupt the mGluR-mediated modulation of dopamine release. We showed that the orthosteric mGluR2 agonist LY379268 (0.1 µM, 1 µM and 10 µM) and mGluR5 positive allosteric modulator CDPPB (1 µM and 10 µM) both attenuated potassium-evoked dopamine release, underscoring their role in modulating dopamine neurotransmission in the nucleus accumbens. Sub-chronic PCP treatment, which caused cognitive deficits measured by performance in the novel object recognition task, modelling aspects of behavioral deficits seen in schizophrenia, induced neurobiological changes that enhanced dopamine release in the nucleus accumbens, but had no effect on mGluR2 or mGluR5 mediated changes in dopamine release. Therefore it is unlikely that schizophrenia-related behavioural changes seen after sub-chronic phencyclidine pre-treatment are mediated through mGluR modulation of dopamine release.
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Affiliation(s)
- Ishan Gupta
- Department of Neuroscience, Psychology and Behaviour, University of Leicester, Lancaster Road, Leicester LE1 9HN, UK
| | - Andrew M J Young
- Department of Neuroscience, Psychology and Behaviour, University of Leicester, Lancaster Road, Leicester LE1 9HN, UK.
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20
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Effects of the Positive Allosteric Modulator of Metabotropic Glutamate Receptor 5, VU-29, on Impairment of Novel Object Recognition Induced by Acute Ethanol and Ethanol Withdrawal in Rats. Neurotox Res 2018; 33:607-620. [PMID: 29294238 PMCID: PMC5871646 DOI: 10.1007/s12640-017-9857-z] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2017] [Revised: 12/15/2017] [Accepted: 12/18/2017] [Indexed: 10/29/2022]
Abstract
Glutamate is essential for learning and memory processes, and acute and chronic exposures to ethanol (or protracted abstinence) alter glutamatergic transmission. In the current study, we investigated the effects of VU-29, positive allosteric modulator of metabotropic glutamate 5 (mGlu5) receptor, on the acute ethanol- and ethanol withdrawal-induced impairment of novel object recognition (NOR) task in rats. The influence of VU-29 (30 mg/kg) on memory retrieval was measured (a) at 4-h delay after acute ethanol administration, as well as (b) after acute withdrawal (24 and 48 h) of repeated (2.0 g/kg, once daily for 7 days) ethanol administration. Additionally, the effects of VU-29 on expression of mGlu5 and mGlu2 receptor proteins in the hippocampus, prefrontal cortex, and striatum were determined 48 h after ethanol withdrawal. Our results indicated that VU-29, given before acute ethanol administration, prevented the ethanol-induced impairments in spatial memory retrieval. Furthermore, VU-29 given before the testing session on the first day of abstinence facilitated NOR performance in ethanol-withdrawn rats at 4- and 24-h delay after administration. Our ELISA results show that VU-29 normalized ethanol withdrawal induced increase in expression of mGlu5 receptor protein in the hippocampus, prefrontal cortex, and striatum, as well as expression of mGlu2 receptor protein in the hippocampus. Thus, results from our study indicate that positive modulation of mGlu5 receptor prevented and reversed ethanol-induced memory impairment. Moreover, mGlu5 (hippocampus, prefrontal cortex, and striatum) and mGlu2 (hippocampus) receptors play an important role in the ethanol-induced recognition memory impairment induced by ethanol withdrawal.
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21
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Caraci F, Nicoletti F, Copani A. Metabotropic glutamate receptors: the potential for therapeutic applications in Alzheimer's disease. Curr Opin Pharmacol 2017; 38:1-7. [PMID: 29278824 DOI: 10.1016/j.coph.2017.12.001] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2017] [Accepted: 12/11/2017] [Indexed: 02/03/2023]
Abstract
A dysfunction of glutamate signaling is implicated at several levels in the pathogenesis of Alzheimer's disease. Currently, metabotropic glutamate receptors, which have a wide distribution in the central nervous system and activate a multitude of cell signaling pathways, are pursued as targets for therapeutic intervention in Alzheimer's disease. Research is still limited, but results underscore the relevance of ongoing studies. Here we discuss the latest updates regarding metabotropic glutamate receptors and their role in Alzheimer's disease, as well as promising metabotropic glutamate receptor ligands that have been investigated in preclinical models of Alzheimer's disease.
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Affiliation(s)
- Filippo Caraci
- Department of Drug Sciences, University of Catania, Catania, Italy; Oasi Institute for Research on Mental Retardation and Brain Aging (IRCCS), Troina, Italy
| | - Ferdinando Nicoletti
- Department of Physiology and Pharmacology, University of Rome Sapienza, Rome, Italy; Neuromed (IRCCS), Pozzilli, Italy
| | - Agata Copani
- Department of Drug Sciences, University of Catania, Catania, Italy; Institute of Biostructure and Bioimaging, National Research Council, Catania, Italy.
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Attenuation of ketamine-induced impairment in verbal learning and memory in healthy volunteers by the AMPA receptor potentiator PF-04958242. Mol Psychiatry 2017; 22:1633-1640. [PMID: 28242871 DOI: 10.1038/mp.2017.6] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/26/2016] [Revised: 11/22/2016] [Accepted: 12/19/2016] [Indexed: 01/03/2023]
Abstract
There is a need to develop treatments for cognitive impairment associated with schizophrenia (CIAS). The significant role played by N-methyl-d-aspartate receptors (NMDARs) in both the pathophysiology of schizophrenia and in neuronal plasticity suggests that facilitation of NMDAR function might ameliorate CIAS. One strategy to correct NMDAR hypofunction is to stimulate α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptors (AMPARs) as AMPAR and NMDAR functioning are coupled and interdependent. In rats and nonhuman primates (NHP), AMPAR potentiators reduce spatial working memory deficits caused by the nonselective NMDAR antagonist ketamine. The current study assessed whether the AMPAR potentiator PF-04958242 would attenuate ketamine-induced deficits in verbal learning and memory in humans. Healthy male subjects (n=29) participated in two randomized treatment periods of daily placebo or PF-04958242 for 5 days separated by a washout period. On day 5 of each treatment period, subjects underwent a ketamine infusion for 75 min during which the effects of PF-04958242/placebo were assessed on ketamine-induced: (1) impairments in verbal learning and recall measured by the Hopkins Verbal Learning Test; (2) impairments in working memory on a CogState battery; and (3) psychotomimetic effects measured by the Positive and Negative Syndrome Scale and Clinician-Administered Dissociative Symptoms Scale. PF-04958242 significantly reduced ketamine-induced impairments in immediate recall and the 2-Back and spatial working memory tasks (CogState Battery), without significantly attenuating ketamine-induced psychotomimetic effects. There were no pharmacokinetic interactions between PF-04958242 and ketamine. Furthermore, PF-04958242 was well tolerated. 'High-impact' AMPAR potentiators like PF-04958242 may have a role in the treatment of the cognitive symptoms, but not the positive or negative symptoms, associated with schizophrenia. The excellent concordance between the preclinical (rat, NHP) and human studies with PF-04958242, and in silico modeling of AMPAR-NMDAR interactions in the hippocampus, highlights the translational value of this study.
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Marszalek-Grabska M, Gibula-Bruzda E, Bodzon-Kulakowska A, Suder P, Gawel K, Talarek S, Listos J, Kedzierska E, Danysz W, Kotlinska JH. ADX-47273, a mGlu5 receptor positive allosteric modulator, attenuates deficits in cognitive flexibility induced by withdrawal from 'binge-like' ethanol exposure in rats. Behav Brain Res 2017; 338:9-16. [PMID: 29030082 DOI: 10.1016/j.bbr.2017.10.007] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2017] [Revised: 10/01/2017] [Accepted: 10/09/2017] [Indexed: 11/15/2022]
Abstract
Repeated exposure to and withdrawal from ethanol induces deficits in spatial reversal learning. Data indicate that metabotropic glutamate 5 (mGlu5) receptors are implicated in synaptic plasticity and learning and memory. These receptors functionally interact with N-methyl-d-aspartate (NMDA) receptors, and activation of one type results in the activation of the other. We examined whether (S)-(4-fluorophenyl)(3-(3-(4-fluorophenyl)-1,2,4-oxadiazol-5-yl)-piperidin-1-yl (ADX-47273), a positive allosteric modulator (PAM) of mGlu5 receptor, attenuates deficits in reversal learning induced by withdrawal (11-13days) from 'binge-like' ethanol input (5.0g/kg, i.g. for 5days) in the Barnes maze (a spatial learning) task in rats. We additionally examined the effects of ADX-47273 on the expression of the NMDA receptors subunit, GluN2B, in the hippocampus and prefrontal cortex, on the 13th day of ethanol withdrawal. Herein, withdrawal from repeated ethanol administration impaired reversal learning, but not the probe trial. Moreover, ADX-47273 (30mg/kg, i.p.) given prior to the first reversal learning trial for 3days in the Barnes maze, significantly enhanced performance in the ethanol-treated group. The 13th day of ethanol abstinence decreased the expression of the GluN2B subunit in the selected brain regions, but ADX-47273 administration increased it. In conclusion, positive allosteric modulation of mGlu5 receptors recovered spatial reversal learning impairment induced by withdrawal from 'binge-like' ethanol exposure. Such effect seems to be correlated with the mGlu5 receptors mediated potentiation of GluN2B-NMDA receptor mediated responses in the hippocampus and prefrontal cortex. Thus, our results emphasize the role of mGlu5 receptor PAM in the adaptive learning impaired by ethanol exposure.
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Affiliation(s)
| | - Ewa Gibula-Bruzda
- Department of Pharmacology and Pharmacodynamics, Medical University, Lublin, Poland
| | - Anna Bodzon-Kulakowska
- Department of Biochemistry and Neurobiology, AGH University of Science and Technology, Krakow, Poland
| | - Piotr Suder
- Department of Biochemistry and Neurobiology, AGH University of Science and Technology, Krakow, Poland
| | - Kinga Gawel
- Department of Pharmacology and Pharmacodynamics, Medical University, Lublin, Poland; Department of Experimental and Clinical Pharmacology, Medical University, Lublin, Poland
| | - Sylwia Talarek
- Department of Pharmacology and Pharmacodynamics, Medical University, Lublin, Poland
| | - Joanna Listos
- Department of Pharmacology and Pharmacodynamics, Medical University, Lublin, Poland
| | - Ewa Kedzierska
- Department of Pharmacology and Pharmacodynamics, Medical University, Lublin, Poland
| | | | - Jolanta H Kotlinska
- Department of Pharmacology and Pharmacodynamics, Medical University, Lublin, Poland.
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Franco R, Martínez-Pinilla E, Navarro G, Zamarbide M. Potential of GPCRs to modulate MAPK and mTOR pathways in Alzheimer's disease. Prog Neurobiol 2017; 149-150:21-38. [PMID: 28189739 DOI: 10.1016/j.pneurobio.2017.01.004] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2016] [Revised: 01/20/2017] [Accepted: 01/22/2017] [Indexed: 02/08/2023]
Abstract
Despite efforts to understand the mechanism of neuronal cell death, finding effective therapies for neurodegenerative diseases is still a challenge. Cognitive deficits are often associated with neurodegenerative diseases. Remarkably, in the absence of consensus biomarkers, diagnosis of diseases such as Alzheimer's still relies on cognitive tests. Unfortunately, all efforts to translate findings in animal models to the patients have been unsuccessful. Alzheimer's disease may be addressed from two different points of view, neuroprotection or cognitive enhancement. Based on recent data, the mammalian target of rapamycin (mTOR) pathway arises as a versatile player whose modulation may impact on mechanisms of both neuroprotection and cognition. Whereas direct targeting of mTOR does not seem to constitute a convenient approach in drug discovery, its indirect modulation by other signaling pathways seems promising. In fact, G-protein-coupled receptors (GPCRs) remain the most common 'druggable' targets and as such pharmacological manipulation of GPCRs with selective ligands may modulate phosphatidylinositol-4,5-bisphosphate 3-kinase (PI3K), mitogen-activated protein (MAP) kinase and mTOR signaling pathways. Thus, GPCRs become important targets for potential drug treatments in different neurodegenerative disorders including, but not limited to, Alzheimer's disease. GPCR-mediated modulation of mTOR may take advantage of different GPCRs coupled to different G-dependent and G-independent signal transduction routes, of functional selectivity and/or of biased agonism. Signals mediated by GPCRs may act as coincidence detectors to achieve different benefits in different stages of the neurodegenerative disease.
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Affiliation(s)
- Rafael Franco
- Department of Biochemistry and Molecular Biomedicine and IBUB (Institute of Biomedicine of the University of Barcelona), University of Barcelona, Barcelona, Spain; Centro de investigación en Red: Enfermedades Neurodegenerativas, CIBERNED, Madrid, Spain
| | - Eva Martínez-Pinilla
- Instituto de Neurociencias del Principado de Asturias (INEUROPA), Departamento de Morfología y Biología Celular, Facultad de Medicina, Universidad de Oviedo, Asturias, Spain
| | - Gemma Navarro
- Department of Biochemistry and Molecular Biomedicine and IBUB (Institute of Biomedicine of the University of Barcelona), University of Barcelona, Barcelona, Spain; Centro de investigación en Red: Enfermedades Neurodegenerativas, CIBERNED, Madrid, Spain
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Sarantis K, Tsiamaki E, Kouvaros S, Papatheodoropoulos C, Angelatou F. Adenosine A₂A receptors permit mGluR5-evoked tyrosine phosphorylation of NR2B (Tyr1472) in rat hippocampus: a possible key mechanism in NMDA receptor modulation. J Neurochem 2015; 135:714-26. [PMID: 26303340 DOI: 10.1111/jnc.13291] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2015] [Revised: 07/23/2015] [Accepted: 08/07/2015] [Indexed: 12/30/2022]
Abstract
A great body of evidence points toward a functional interaction between metabotropic glutamate 5 receptors (mGluR5) and NMDA receptors (NMDAR) that enhances synaptic plasticity and cognition. However, the molecular mechanism underlying this interaction remains unclear. Here, we show that co-activation of mGluR5 and NMDAR in hippocampal slices synergistically leads to a robust phosphorylation of NR2B (Tyr1472), which is Src kinase dependent and is enabled by endogenous adenosine acting on A2A receptors. As it is well known, NR2B (Tyr1472) phosphorylation anchors NR2B-containing NMDARs to the surface of post-synaptic membranes, preventing their internalization. This is supported by our electrophysiological experiments showing that co-activation of mGluR5 and NMDARs robustly enhances NMDAR-dependent neuronal excitability recorded in CA1 hippocampal region, which temporally coincides with the robust increase in NR2B (Tyr1472) phosphorylation, depends on Src kinases and is also permitted by A2A receptors. Thus, we strongly suggest that NR2B (Tyr1472) phosphorylation constitutes, at least to some extent, the molecular mechanism underlying the mGluR5-mediated enhancement of NMDAR-dependent responses, which is modulated by A2A receptors. A better understanding of the molecular basis of mGluR5/NMDAR interaction would elucidate their role in synaptic plasticity processes as well as in pathological conditions. We propose the following molecular mechanism by which metabotropic Glutamate Receptor 5 (mGluR5) potentiate ionotropic Glutamate N-Methyl-D-Aspartate Receptor (NMDAR) responses in rat hippocampus. Co-activation of mGLUR5/NMDAR activates Src kinases, leading to NR2B(Tyr1472) phosphorylation, which anchors NR2B-containing NMDAR to the plasma membrane, thus inducing a robust increase in the NMDA-dependent excitability. Interestingly, adenosine A2A receptors license the mGluR5-induced NR2B(Tyr1472) phosphorylation.
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Affiliation(s)
| | - Eirini Tsiamaki
- Physiology Department, Medical School, University of Patras, Patras, Greece
| | - Stylianos Kouvaros
- Physiology Department, Medical School, University of Patras, Patras, Greece
| | | | - Fevronia Angelatou
- Physiology Department, Medical School, University of Patras, Patras, Greece
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Bhardwaj SK, Ryan RT, Wong TP, Srivastava LK. Loss of dysbindin-1, a risk gene for schizophrenia, leads to impaired group 1 metabotropic glutamate receptor function in mice. Front Behav Neurosci 2015; 9:72. [PMID: 25859193 PMCID: PMC4374471 DOI: 10.3389/fnbeh.2015.00072] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2014] [Accepted: 03/06/2015] [Indexed: 11/13/2022] Open
Abstract
The expression of dysbindin-1, a protein coded by the risk gene dtnbp1, is reduced in the brains of schizophrenia patients. Evidence indicates a role of dysbindin-1 in dopaminergic and glutamatergic transmission. Glutamatergic transmission and plasticity at excitatory synapses is critically regulated by G-protein coupled metabotropic glutamate receptor (mGluR) family members, that have been implicated in schizophrenia. Here, we report a role of dysbindin-1 in hippocampal group 1 mGluR (mGluRI) function in mice. In hippocampal synaptoneurosomal preparations from sandy (sdy) mice, that have a loss of function mutation in dysbindin-1 gene, we observed a striking reduction in mGluRI agonist [(S)-3, 5-dihydroxyphenylglycine] (DHPG)-induced phosphorylation of extracellular signal regulated kinase 1/2 (ERK1/2). This mGluR-ERK1/2 deficit occurred in the absence of significant changes in protein levels of the two members of the mGluRI family (i.e., mGluR1 and mGluR5) or in another mGluRI signaling pathway, i.e., protein kinase C (PKC). Aberrant mGluRI-ERK1/2 signaling affected hippocampal synaptic plasticity in the sdy mutants as DHPG-induced long-term depression (LTD) at CA1 excitatory synapses was significantly reduced. Behavioral data suggest that the mGluRI hypofunction may underlie some of the cognitive abnormalities described in sdy mice as the administration of CDPPB (3-cyano-N-(1, 3-diphenyl-1H-pyrazol-5-yl benzamide), a positive allosteric modulator of mGluR5, rescued short-term object recognition and spatial learning and memory deficits in these mice. Taken together, our data suggest a novel role of dysbindin-1 in regulating mGluRI functions.
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Affiliation(s)
- Sanjeev K Bhardwaj
- Department of Psychiatry and Integrated Programme in Neuroscience, Douglas Mental Health University Institute, McGill University Montreal, QC, Canada
| | - Richard T Ryan
- Department of Psychiatry and Integrated Programme in Neuroscience, Douglas Mental Health University Institute, McGill University Montreal, QC, Canada
| | - Tak Pan Wong
- Department of Psychiatry and Integrated Programme in Neuroscience, Douglas Mental Health University Institute, McGill University Montreal, QC, Canada
| | - Lalit K Srivastava
- Department of Psychiatry and Integrated Programme in Neuroscience, Douglas Mental Health University Institute, McGill University Montreal, QC, Canada
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mGluR5 positive allosteric modulation and its effects on MK-801 induced set-shifting impairments in a rat operant delayed matching/non-matching-to-sample task. Psychopharmacology (Berl) 2015; 232:251-8. [PMID: 24973895 PMCID: PMC4278949 DOI: 10.1007/s00213-014-3653-8] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/30/2013] [Accepted: 06/08/2014] [Indexed: 10/25/2022]
Abstract
RATIONALE Positive allosteric modulators (PAMs) of type 5 metabotropic glutamate receptors (mGluR5) exert pro-cognitive effects in animal models of various neuropsychiatric diseases. However, few studies to date have examined ability of mGluR5 PAMs to reverse cognitive deficits in operant delayed matching/non-matching-to-sample (DMS/DNMS) tasks. OBJECTIVES This study aims to determine the ability of the mGluR5 PAM 3-cyano-N-(1,3-diphenyl-1H-pyrazol-5-yl)benzamide (CDPPB) to reverse set-shifting deficits induced by the N-methyl-D-aspartate (NMDA) receptor antagonist MK-801. METHODS Male Sprague-Dawley rats were initially trained to lever press for sucrose reinforcement under either DMS or DNMS conditions. Following successful acquisition of the task, reinforcement conditions were reversed (DNMS → DMS or DMS → DNMS). In Experiment 1, rats were treated daily prior to each session with vehicle/vehicle, vehicle/MK-801 (0.06 mg/kg) simultaneously, CDPPB (20 mg/kg)/MK-801 simultaneously, or CDPPB 30 min prior to MK-801. In Experiment 2, rats were treated with either vehicle/vehicle, vehicle/MK-801, or CDPPB 30 min prior to MK-801 only prior to sessions that followed task reversal. RESULTS In Experiment 1, no group differences in initial task acquisition were observed. Rats treated with vehicle/MK-801 showed significant set-shifting impairments following task reversal, which were partially attenuated by simultaneous administration of CDPPB/MK-801 and completely precluded by administration of CDPPB 30 min prior to MK-801. In Experiment 2, MK-801 did not impair reversal learning, and no other group differences were observed. CONCLUSIONS MK-801-induced deficits in operant set-shifting ability were prevented by pretreatment with CDPPB. MK-801 did not produce deficits in task learning when treatment was initiated following task reversal.
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Pollard M, Bartolome JM, Conn PJ, Steckler T, Shaban H. Modulation of neuronal microcircuit activities within the medial prefrontal cortex by mGluR5 positive allosteric modulator. J Psychopharmacol 2014; 28:935-46. [PMID: 25031220 PMCID: PMC4356529 DOI: 10.1177/0269881114542856] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Suppressing anxiety and fear memory relies on bidirectional projections between the medial prefrontal cortex and the amygdala. Positive allosteric modulators of mGluR5 improve cognition in animal models of schizophrenia and retrieval of newly formed associations such as extinction of fear-conditioned behaviour. The increase in neuronal network activities of the medial prefrontal cortex is influenced by both mGluR1 and mGluR5; however, it is not well understood how they modulate network activities and downstream information processing. To map mGluR5-mediated network activity in relation to its emergence as a viable cognitive enhancer, we tested group I mGluR compounds on medial prefrontal cortex network activity via multi-electrode array neuronal spiking and whole-cell patch clamp recordings. Results indicate that mGluR5 activation promotes feed-forward inhibition that depends on recruitment of neuronal activity by carbachol-evoked up states. The rate of neuronal spiking activity under the influence of carbachol was reduced by the mGluR5 positive allosteric modulator, N-(1,3-Diphenyl-1H-pyrazolo-5-yl)-4-nitrobenzamide (VU-29), and enhanced by the mGluR5 negative allosteric modulator, 3-((2-methyl-1,3-thiazol-4-yl)ethynyl)pyridine hydrochloride (MTEP). Spontaneous inhibitory post-synaptic currents were increased upon application of carbachol and in combination with VU-29. These results emphasize a bias towards tonic mGluR5-mediated inhibition that might serve as a signal-to-noise enhancer of sensory inputs projected from associated limbic areas onto the medial prefrontal cortex neuronal microcircuit.
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Affiliation(s)
| | | | - P Jeffrey Conn
- Department of Pharmacology, and the Vanderbilt Center for Neuroscience Drug Discovery 2, Vanderbilt University Medical School, Nashville, TN, USA
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Loane DJ, Stoica BA, Tchantchou F, Kumar A, Barrett JP, Akintola T, Xue F, Conn PJ, Faden AI. Novel mGluR5 positive allosteric modulator improves functional recovery, attenuates neurodegeneration, and alters microglial polarization after experimental traumatic brain injury. Neurotherapeutics 2014; 11:857-69. [PMID: 25096154 PMCID: PMC4391388 DOI: 10.1007/s13311-014-0298-6] [Citation(s) in RCA: 63] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Traumatic brain injury (TBI) causes microglial activation and related neurotoxicity that contributes to chronic neurodegeneration and loss of neurological function. Selective activation of metabotropic glutamate receptor 5 (mGluR5) by the orthosteric agonist (RS)-2-chloro-5-hydroxyphenylglycine (CHPG), is neuroprotective in experimental models of TBI, and has potent anti-inflammatory effects in vitro. However, the therapeutic potential of CHPG is limited due to its relatively weak potency and brain permeability. Highly potent, selective and brain penetrant mGluR5 positive allosteric modulators (PAMs) have been developed and show promise as therapeutic agents. We evaluated the therapeutic potential of a novel mGluR5 PAM, VU0360172, after controlled cortical impact (CCI) in mice. Vehicle, VU0360172, or VU0360172 plus mGluR5 antagonist (MTEP), were administered systemically to CCI mice at 3 h post-injury; lesion volume, hippocampal neurodegeneration, microglial activation, and functional recovery were assessed through 28 days post-injury. Anti-inflammatory effects of VU0360172 were also examined in vitro using BV2 and primary microglia. VU0360172 treatment significantly reduced the lesion, attenuated hippocampal neurodegeneration, and improved motor function recovery after CCI. Effects were mediated by mGluR5 as co-administration of MTEP blocked the protective effects of VU0360172. VU0360172 significantly reduced CD68 and NOX2 expression in activated microglia in the cortex at 28 days post-injury, and also suppressed pro-inflammatory signaling pathways in BV2 and primary microglia. In addition, VU0360172 treatment shifted the balance between M1/M2 microglial activation states towards an M2 pro-repair phenotype. This study demonstrates that VU0360172 confers neuroprotection after experimental TBI, and suggests that mGluR5 PAMs may be promising therapeutic agents for head injury.
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Affiliation(s)
- David J. Loane
- />Department of Anesthesiology and Center for Shock, Trauma, and Anesthesiology Research (STAR), University of Maryland School of Medicine, Health Sciences Facility II (HSFII), #S247, 20 Penn Street, Baltimore, MD 21201 USA
| | - Bogdan A. Stoica
- />Department of Anesthesiology and Center for Shock, Trauma, and Anesthesiology Research (STAR), University of Maryland School of Medicine, Health Sciences Facility II (HSFII), #S247, 20 Penn Street, Baltimore, MD 21201 USA
| | - Flaubert Tchantchou
- />Department of Anesthesiology and Center for Shock, Trauma, and Anesthesiology Research (STAR), University of Maryland School of Medicine, Health Sciences Facility II (HSFII), #S247, 20 Penn Street, Baltimore, MD 21201 USA
| | - Alok Kumar
- />Department of Anesthesiology and Center for Shock, Trauma, and Anesthesiology Research (STAR), University of Maryland School of Medicine, Health Sciences Facility II (HSFII), #S247, 20 Penn Street, Baltimore, MD 21201 USA
| | - James P. Barrett
- />Department of Anesthesiology and Center for Shock, Trauma, and Anesthesiology Research (STAR), University of Maryland School of Medicine, Health Sciences Facility II (HSFII), #S247, 20 Penn Street, Baltimore, MD 21201 USA
| | - Titilola Akintola
- />Department of Anesthesiology and Center for Shock, Trauma, and Anesthesiology Research (STAR), University of Maryland School of Medicine, Health Sciences Facility II (HSFII), #S247, 20 Penn Street, Baltimore, MD 21201 USA
| | - Fengtian Xue
- />Department of Pharmaceutical Sciences, University of Maryland School of Pharmacy, Baltimore, MD USA
| | - P. Jeffrey Conn
- />Department of Pharmacology and Vanderbilt Center for Neuroscience Drug Discovery, Vanderbilt University Medical Center, Nashville, TN USA
| | - Alan I. Faden
- />Department of Anesthesiology and Center for Shock, Trauma, and Anesthesiology Research (STAR), University of Maryland School of Medicine, Health Sciences Facility II (HSFII), #S247, 20 Penn Street, Baltimore, MD 21201 USA
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Mølck C, Harpsøe K, Gloriam DE, Mathiesen JM, Nielsen SM, Bräuner-Osborne H. mGluR5: Exploration of Orthosteric and Allosteric Ligand Binding Pockets and Their Applications to Drug Discovery. Neurochem Res 2014; 39:1862-75. [DOI: 10.1007/s11064-014-1248-8] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2013] [Revised: 01/14/2014] [Accepted: 01/21/2014] [Indexed: 10/25/2022]
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Dendritic generation of mGluR-mediated slow afterdepolarization in layer 5 neurons of prefrontal cortex. J Neurosci 2013; 33:13518-32. [PMID: 23946410 DOI: 10.1523/jneurosci.2018-13.2013] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Many prefrontal cortex (PFC)-dependent tasks require individual neurons to fire persistently in response to brief stimuli. Persistent activity is proposed to involve changes in intrinsic properties, resulting in an increased sensitivity to inputs. The dendrite is particularly relevant to this hypothesis because it receives the majority of synaptic inputs and is enriched for conductances implicated in persistent firing. We provide evidence that dendritic conductances contribute to persistent activity-related changes in intrinsic properties. The effects of Group 1 metabotropic glutamate receptor (mGluR) activation on persistent activity-related properties were tested in two classes of rat L5 neurons with distinct membrane properties: those projecting to the pons (CPn) and those projecting across the commissure to the contralateral cortex (COM). mGluR activation produced long-term changes in the subthreshold properties of CPn, but not COM neurons. These changes were indicative of a decrease in hyperpolarization-activated cation nonselective current (I(h)) at the soma and dendrite. mGluR activation also transiently increased the amplitude of the postburst slow afterdepolarization potential (sADP) at the soma of both neuron types. Interestingly, the sADP occurred along the extent of the apical dendrite in CPn and COM neurons. Simultaneous somatic/dendritic recordings revealed that the dendritic sADP does not result solely from passive propagation of the somatic sADP. Focal mGluR activation in L5, near the soma or at the border of L1/L2, near the tuft, generates a local sADP. This dendritic depolarization may act synergistically with synaptic input to regulate mnemonic activity in PFC.
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Mereu M, Bonci A, Newman AH, Tanda G. The neurobiology of modafinil as an enhancer of cognitive performance and a potential treatment for substance use disorders. Psychopharmacology (Berl) 2013; 229:415-34. [PMID: 23934211 PMCID: PMC3800148 DOI: 10.1007/s00213-013-3232-4] [Citation(s) in RCA: 87] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/17/2013] [Accepted: 07/28/2013] [Indexed: 12/31/2022]
Abstract
RATIONALE AND OBJECTIVES Modafinil (MOD) and its R-enantiomer (R-MOD) are approved medications for narcolepsy and other sleep disorders. They have also been used, off-label, as cognitive enhancers in populations of patients with mental disorders, including substance abusers that demonstrate impaired cognitive function. A debated nonmedical use of MOD in healthy individuals to improve intellectual performance is raising questions about its potential abuse liability in this population. RESULTS AND CONCLUSIONS MOD has low micromolar affinity for the dopamine transporter (DAT). Inhibition of dopamine (DA) reuptake via the DAT explains the enhancement of DA levels in several brain areas, an effect shared with psychostimulants like cocaine, methylphenidate, and the amphetamines. However, its neurochemical effects and anatomical pattern of brain area activation differ from typical psychostimulants and are consistent with its beneficial effects on cognitive performance processes such as attention, learning, and memory. At variance with typical psychostimulants, MOD shows very low, if any, abuse liability, in spite of its use as a cognitive enhancer by otherwise healthy individuals. Finally, recent clinical studies have focused on the potential use of MOD as a medication for treatment of drug abuse, but have not shown consistent outcomes. However, positive trends in several result measures suggest that medications that improve cognitive function, like MOD or R-MOD, may be beneficial for the treatment of substance use disorders in certain patient populations.
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Affiliation(s)
- Maddalena Mereu
- Molecular Targets & Medication Discovery Branch, National Institute on Drug Abuse, Intramural Research Program, National Institutes of Health, DHHS; 251 Bayview Blvd., NIDA suite 200, Baltimore, MD, 21224
| | - Antonello Bonci
- Synaptic Plasticity Section, Cellular Neurobiology Research Branch, National Institute on Drug Abuse, Intramural Research Program, National Institutes of Health, DHHS; 251 Bayview Blvd., NIDA suite 200, Baltimore, MD, 21224
| | - Amy Hauck Newman
- Molecular Targets & Medication Discovery Branch, National Institute on Drug Abuse, Intramural Research Program, National Institutes of Health, DHHS; 251 Bayview Blvd., NIDA suite 200, Baltimore, MD, 21224
| | - Gianluigi Tanda
- Molecular Targets & Medication Discovery Branch, National Institute on Drug Abuse, Intramural Research Program, National Institutes of Health, DHHS; 251 Bayview Blvd., NIDA suite 200, Baltimore, MD, 21224
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Timmer KM, Steketee JD. Group I metabotropic glutamate receptors in the medial prefrontal cortex: role in mesocorticolimbic glutamate release in cocaine sensitization. Synapse 2013; 67:887-96. [PMID: 23913407 DOI: 10.1002/syn.21699] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2013] [Revised: 07/02/2013] [Accepted: 07/12/2013] [Indexed: 11/08/2022]
Abstract
Cocaine sensitization is associated with increased excitability of pyramidal projection neurons in the medial prefrontal cortex. Such hyperexcitability is presumed to increase glutamatergic input to the nucleus accumbens and ventral tegmental area. This study examined the effects of medial prefrontal cortex Group I metabotropic glutamate receptor activation on glutamate levels in the medial prefrontal cortex, nucleus accumbens, and ventral tegmental area in sensitized and control animals. Male Sprague-Dawley rats received four daily injections of cocaine (15 mg/kg, i.p.) or saline (1 mL/kg i.p.). One, 7, or 21 days from the fourth injection, dual-probe microdialysis experiments were performed wherein Group I metabotropic glutamate receptor agonist DHPG was infused into the medial prefrontal cortex and glutamate levels in this region as well as the nucleus accumbens or ventral tegmental area were examined. Intra-mPFC DHPG infusion increased glutamate levels in the medial prefrontal cortex at 1 and 7 days withdrawal, and in the nucleus accumbens at 21 days withdrawal in sensitized rats. These results suggest Group I metabotropic glutamate receptor activation may contribute to the increased excitability of medial prefrontal cortex pyramidal neurons in sensitized animals.
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Affiliation(s)
- Kristin M Timmer
- Department of Pharmacology, University of Tennessee Health Science Center, Memphis, Tennessee, 38163
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Feasibility, safety, and efficacy of the combination of D-serine and computerized cognitive retraining in schizophrenia: an international collaborative pilot study. Neuropsychopharmacology 2013; 38:492-503. [PMID: 23093223 PMCID: PMC3547200 DOI: 10.1038/npp.2012.208] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
The combination of pharmacotherapy and cognitive retraining (CRT) for the cognitive deficits of schizophrenia may be more efficacious than either approach alone, but this has not yet been tested. This study evaluated the feasibility, safety, tolerability, and efficacy of 12 weeks of D-serine, combined with CRT in the treatment of cognitive deficits in schizophrenia at two academic sites in parallel, in India and the United States. In a randomized, partial double-blind, placebo-controlled, parallel-group design, 104 schizophrenia subjects (US site=22, Indian site=82) were randomized to: (1) D-serine (30 mg/kg)+CRT (5 h/week), (2) D-serine+control CRT, (3) CRT+placebo D-serine, and (4) placebo+control CRT. Completion rates were 84 and 100% in the Indian and US samples, respectively. On various outcome measures of safety and tolerability, the interventions were well tolerated. D-Serine and CRT did not show any significant effect on the Global Cognitive Index, although both interventions showed differential site effects on individual test performance. CRT resulted in a significant improvement in Verbal Working Memory, and a trend toward improvement in Attention/Vigilance. This is the first study to demonstrating the feasibility, safety, and tolerability of combination pharmacotherapy and CRT in a multicenter international clinical trial. These preliminary findings provide support for future studies using higher doses of D-serine that have been shown to be efficacious or other pharmacotherapies, along with the newer cognitive remediation strategies that are individualized and that target basic information processing.
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Cavas M, Scesa G, Navarro JF. Effects of MPEP, a selective metabotropic glutamate mGlu5 ligand, on sleep and wakefulness in the rat. Prog Neuropsychopharmacol Biol Psychiatry 2013; 40:18-25. [PMID: 23022670 DOI: 10.1016/j.pnpbp.2012.09.011] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/08/2012] [Revised: 09/18/2012] [Accepted: 09/18/2012] [Indexed: 10/27/2022]
Abstract
Metabotropic glutamate receptors (mGlu) have been implicated in the regulation of physiological and behavioral processes. Pharmacological evidence involves group I mGlu receptors in the regulation of emotional states and antagonism of these receptors has been proposed as a novel class of anxiolytic drugs having also antidepressant effects. Here, the effects of mGlu5 receptor selective modulation on sleep and wake states are explored. 32 male Wistar rats were implanted with electrodes for recording sleep and wake states. 2-Methyl-6-(phenylethynyl)pyridine hydrochloride (MPEP hydrochloride, 5, 10, and 20 mg/kg, i.p.), a potent, selective and systemically active mGlu5 receptor negative allosteric modulator, or vehicle was administered 1 h after the beginning of the light period. Sleep recordings were conducted for 3 h. MPEP (5, 10, and 20 mg/kg) significantly suppressed rapid eye movement (REM) sleep, decreasing the number of episodes and mean episode duration, and increased its latency. A reduction of light and deep slow wave sleep (SWS) latency was observed in the groups receiving 10 or 20 mg/kg, increasing latency to first wakefulness episode. 10 mg/kg of MPEP also increased non rapid eye movement sleep (NREM). The present results suggest that mGlu5 receptors might be involved in sleep regulation, more specifically in REM sleep, and drugs that block these receptors could potentially benefit the treatment of pathologies were REM sleep is enhanced.
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Affiliation(s)
- María Cavas
- Department of Psychobiology, Faculty of Psychology, Campus de Teatinos s/n, University of Málaga, 29071 Málaga, Spain.
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Piers TM, Kim DH, Kim BC, Regan P, Whitcomb DJ, Cho K. Translational Concepts of mGluR5 in Synaptic Diseases of the Brain. Front Pharmacol 2012. [PMID: 23205012 PMCID: PMC3506921 DOI: 10.3389/fphar.2012.00199] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
The G-protein coupled receptor family of glutamate receptors, termed metabotropic glutamate receptors (mGluRs), are implicated in numerous cellular mechanisms ranging from neural development to the processing of cognitive, sensory, and motor information. Over the last decade, multiple mGluR-related signal cascades have been identified at excitatory synapses, indicating their potential roles in various forms of synaptic function and dysfunction. This review highlights recent studies investigating mGluR5, a subtype of group I mGluRs, and its association with a number of developmental, psychiatric, and senile synaptic disorders with respect to associated synaptic proteins, with an emphasis on translational pre-clinical studies targeting mGluR5 in a range of synaptic diseases of the brain.
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Affiliation(s)
- Thomas M Piers
- School of Clinical Sciences, Faculty of Medicine and Dentistry, University of Bristol Bristol, UK
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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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Tomasini MC, Beggiato S, Ferraro L, Tanganelli S, Marani L, Lorenzini L, Antonelli T. Prenatal exposure to 2,3,7,8-tetrachlorodibenzo-p-dioxin produces alterations in cortical neuron development and a long-term dysfunction of glutamate transmission in rat cerebral cortex. Neurochem Int 2012; 61:759-66. [DOI: 10.1016/j.neuint.2012.07.004] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2011] [Revised: 06/25/2012] [Accepted: 07/03/2012] [Indexed: 10/28/2022]
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Cognitive Deficits in Schizophrenia and Alcoholism: A Review of the Evidence and Findings on the Effects of Treatment on Cognitive Functioning in Patients With Dual Diagnoses. J Dual Diagn 2012. [DOI: 10.1080/15504263.2012.696534] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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Moutin E, Raynaud F, Roger J, Pellegrino E, Homburger V, Bertaso F, Ollendorff V, Bockaert J, Fagni L, Perroy J. Dynamic remodeling of scaffold interactions in dendritic spines controls synaptic excitability. ACTA ACUST UNITED AC 2012; 198:251-63. [PMID: 22801779 PMCID: PMC3410417 DOI: 10.1083/jcb.201110101] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022]
Abstract
Synaptic activity–dependent remodeling of the glutamate receptor scaffold complex generates a negative feedback loop that limits further NMDA receptor activation. Scaffolding proteins interact with membrane receptors to control signaling pathways and cellular functions. However, the dynamics and specific roles of interactions between different components of scaffold complexes are poorly understood because of the dearth of methods available to monitor binding interactions. Using a unique combination of single-cell bioluminescence resonance energy transfer imaging in living neurons and electrophysiological recordings, in this paper, we depict the role of glutamate receptor scaffold complex remodeling in space and time to control synaptic transmission. Despite a broad colocalization of the proteins in neurons, we show that spine-confined assembly/disassembly of this scaffold complex, physiologically triggered by sustained activation of synaptic NMDA (N-methyl-d-aspartate) receptors, induces physical association between ionotropic (NMDA) and metabotropic (mGlu5a) synaptic glutamate receptors. This physical interaction results in an mGlu5a receptor–mediated inhibition of NMDA currents, providing an activity-dependent negative feedback loop on NMDA receptor activity. Such protein scaffold remodeling represents a form of homeostatic control of synaptic excitability.
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Affiliation(s)
- Enora Moutin
- Centre national de la recherche scientifique, UMR-5203, Institut de Génomique Fonctionnelle, F-34000 Montpellier, Cedex 16, France
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Horio M, Fujita Y, Hashimoto K. Therapeutic effects of metabotropic glutamate receptor 5 positive allosteric modulator CDPPB on phencyclidine-induced cognitive deficits in mice. Fundam Clin Pharmacol 2012; 27:483-8. [PMID: 22594375 DOI: 10.1111/j.1472-8206.2012.01045.x] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2011] [Revised: 04/10/2012] [Accepted: 04/23/2012] [Indexed: 11/29/2022]
Abstract
This study was undertaken to examine the effects of CDPPB (3-cyano-N-(1,3-diphenyl-1H-pyrazol-5-yl)benzamide), a positive allosteric modulator (PAM) of metabotropic glutamate receptor 5 (mGlu₅), on cognitive deficits in mice after repeated administration of the N-methyl-D-aspartate (NMDA) receptor antagonist phencyclidine (PCP). In the novel object recognition test, PCP (10 mg/kg/day for 10 days)-induced cognitive deficits in mice were not improved by a single administration of CDPPB (10 mg/kg/day). However, PCP (10 mg/kg/day for 10 days)-induced cognitive deficits in mice were significantly improved by subsequent subchronic (14 days) administration of CDPPB (10 mg/kg/day), but not of CDPPB (1.0 mg/kg/day). This study suggests that PCP-induced cognitive deficits in mice are improved by subsequent subchronic administration of CDPPB. Therefore, mGlu₅ PAMs would be potential therapeutic drugs for cognitive deficits in schizophrenia.
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Affiliation(s)
- Mao Horio
- Division of Clinical Neuroscience, Chiba University Center for Forensic Mental Health, 1-8-1, Inohana, Chiba 260-8670, Japan
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Examination of a role for metabotropic glutamate receptor 5 in the medial prefrontal cortex in cocaine sensitization in rats. Psychopharmacology (Berl) 2012; 221:91-100. [PMID: 22147256 DOI: 10.1007/s00213-011-2548-1] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/31/2011] [Accepted: 10/14/2011] [Indexed: 02/02/2023]
Abstract
RATIONALE Glutamatergic projection neurons in the medial prefrontal cortex (mPFC) are hyperexcitable in cocaine-sensitized animals, resulting in increased excitatory output to addiction-associated regions such as the ventral tegmental area (VTA) and nucleus accumbens. Evidence suggests that Group I metabotropic glutamate receptor 5 (mGluR5) is necessary for cocaine sensitization, and stimulation of this receptor in the mPFC potentially alters cell excitability directly through glutamate release or indirectly through downstream signaling cascades. OBJECTIVES AND METHODS Experiments in this report examined the role of mPFC mGluR5 in behavioral sensitization to cocaine. Group I mGluR agonist dihydroxyphenylglycine (DHPG) (15 nmol/side), mGluR5 antagonist 3((2-methyl-4-thiazolyl)ethynyl)pyridine (MTEP) (15 nmol/side), mGluR1 antagonist YM298198 (15 nmol/side), AMPA receptor antagonist CNQX (1 nmol/side), and/or saline were administered through cannulae implanted 1 mm above the mPFC and/or VTA in male rats. Cocaine (15 mg/kg, i.p.) was systemically administered for four consecutive days to induce sensitization and/or once on test day immediately preceding locomotor monitoring. RESULTS Intra-mPFC DHPG induced an mGluR5-mediated cross-sensitization to cocaine preventable through the prior administration of an AMPA receptor antagonist in the VTA. Furthermore, mGluR5 blockade in the mPFC failed to prevent the initiation of sensitization. However, intra-mPFC injections of the mGluR5 antagonist MTEP prevented the expression of cocaine sensitization at 21, but not 7, days following daily cocaine injections suggesting a possible role for mPFC mGluR5 in the persistence of the cocaine-sensitized state. CONCLUSIONS These data suggest that stimulation of mGluR5s in the mPFC is sufficient to induce cocaine sensitization and is necessary for the expression of this sensitized response.
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Kiritoshi T, Sun H, Ren W, Stauffer SR, Lindsley CW, Conn PJ, Neugebauer V. Modulation of pyramidal cell output in the medial prefrontal cortex by mGluR5 interacting with CB1. Neuropharmacology 2012; 66:170-8. [PMID: 22521499 DOI: 10.1016/j.neuropharm.2012.03.024] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2011] [Revised: 03/27/2012] [Accepted: 03/29/2012] [Indexed: 01/20/2023]
Abstract
The medial prefrontal cortex (mPFC) serves executive cognitive functions such as decision-making that are impaired in neuropsychiatric disorders and pain. We showed previously that amygdala-driven abnormal inhibition and decreased output of mPFC pyramidal cells contribute to pain-related impaired decision-making (Ji et al., 2010). Therefore, modulating pyramidal output is desirable therapeutic goal. Targeting metabotropic glutamate receptor subtype mGluR5 has emerged as a cognitive-enhancing strategy in neuropsychiatric disorders, but synaptic and cellular actions of mGluR5 in the mPFC remain to be determined. The present study determined synaptic and cellular actions of mGluR5 to test the hypothesis that increasing mGluR5 function can enhance pyramidal cell output. Whole-cell voltage- and current-clamp recordings were made from visually identified pyramidal neurons in layer V of the mPFC in rat brain slices. Both the prototypical mGluR5 agonist CHPG and a positive allosteric modulator (PAM) for mGluR5 (VU0360172) increased synaptically evoked spiking (E-S coupling) in mPFC pyramidal cells. The facilitatory effects of CHPG and VU0360172 were inhibited by an mGluR5 antagonist (MTEP). CHPG, but not VU0360172, increased neuronal excitability (frequency-current [F-I] function). VU0360172, but not CHPG, increased evoked excitatory synaptic currents (EPSCs) and amplitude, but not frequency, of miniature EPSCs, indicating a postsynaptic action. VU0360172, but not CHPG, decreased evoked inhibitory synaptic currents (IPSCs) through an action that involved cannabinoid receptor CB1, because a CB1 receptor antagonist (AM281) blocked the inhibitory effect of VU0360172 on synaptic inhibition. VU0360172 also increased and prolonged CB1-mediated depolarization-induced suppression of synaptic inhibition (DSI). Activation of CB1 with ACEA decreased inhibitory transmission through a presynaptic mechanism. The results show that increasing mGluR5 function enhances mPFC output. This effect can be accomplished by increasing excitability with an orthosteric agonist (CHPG) or by increasing excitatory synaptic drive and CB1-mediated presynaptic suppression of synaptic inhibition ("dis-inhibition") with a PAM (VU0360172). Therefore, mGluR5 may be a useful target in conditions of impaired mPFC output. This article is part of a Special Issue entitled 'Metabotropic Glutamate Receptors'.
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Affiliation(s)
- Takaki Kiritoshi
- Department of Neuroscience and Cell Biology, The University of Texas Medical Branch, 301 University Blvd. Galveston, TX 77555-1069, USA.
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Selective remediation of reversal learning deficits in the neurodevelopmental MAM model of schizophrenia by a novel mGlu5 positive allosteric modulator. Neuropsychopharmacology 2012; 37:1057-66. [PMID: 22129780 PMCID: PMC3280638 DOI: 10.1038/npp.2011.298] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Based on the glutamatergic hypothesis of schizophrenia we assessed the effects of a novel mGlu5 positive allosteric modulator, LSN2463359 [N-(1-methylethyl)-5-(pyridin-4-ylethynyl)pyridine-2-carboxamide] on deficits in cognitive flexibility in two distinct rodent models of schizophrenia, the neurodevelopmental MAM E17 model and the acute PCP model. Cognitive flexibility was measured with the intra-dimensional and extra-dimensional set-shifting and reversal learning digging paradigm. Regional effects of MAM on the expression of parvalbumin-positive cells (PV) and mGlu5 receptors were also examined, to further characterize the model. Results showed that LSN2463359 selectively attenuated reversal learning deficits in the MAM but not acute PCP model. Whilst both models led to deficits in reversal learning and extra-dimensional set-shifting, the reversal impairments were qualitatively distinct, with MAM increasing perseverative responding, whereas the PCP deficit was mainly due to the inability of rats to maintain reinforced choice behavior. Reduction of PV and mGlu5 expression was found in the MAM model in several regions of importance in schizophrenia, such as the orbitofrontal and medial prefrontal cortex, which also mediate reversal learning and extra-dimensional set-shifting. The present findings confirm that the positive modulation of mGlu5 receptors may have beneficial effects in the treatment of certain aspects of cognitive impairment associated with schizophrenia. This study also illustrates the importance of studying putative cognitive enhancing drug effects in a number of models which may have implications for the future development of the compound.
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Whittington MA, Roopun AK, Traub RD, Davies CH. Circuits and brain rhythms in schizophrenia: a wealth of convergent targets. Curr Opin Pharmacol 2012; 11:508-14. [PMID: 21555247 DOI: 10.1016/j.coph.2011.04.010] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2011] [Accepted: 04/17/2011] [Indexed: 11/26/2022]
Abstract
Few common neurological illnesses trace back to single molecular disturbances. Many disparate putative causes may co-associate with a single disease state. However, uncovering functional, hierarchical networks of underlying mechanisms can provide a framework in which many primary pathologies converge on more complex, single higher level correlates of disease. This article focuses on cognitive deficits associated with schizophrenia to illustrate: a) How non-invasive EEG biomarkers of cognitive function constitute such a 'higher level correlate' of underlying pathologies. b) How derangement of multiple, cell-specific, molecular processes can converge on such EEG-visible, correlates of disrupted cognitive function. This approach suggests that evidence-based design of multi-target therapies may take advantage of hierarchical patterns of convergence to improve both efficacy and selectivity of disease-intervention.
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Affiliation(s)
- Miles A Whittington
- Institute of Neuroscience, The Medical School, Framlington Place, Newcastle University, Newcastle NE2 4HH, UK.
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Maurice P, Benleulmi-Chaachoua A, Jockers R. Differential assembly of GPCR signaling complexes determines signaling specificity. Subcell Biochem 2012; 63:225-40. [PMID: 23161141 DOI: 10.1007/978-94-007-4765-4_12] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Recent proteomic and biochemical evidence indicates that cellular -signaling is organized in protein modules. G protein-coupled receptors (GPCRs) are privileged entry points for extracellular signals that are transmitted through the plasma membrane into the cell. The adequate cellular response and signaling specificity is regulated by GPCR-associated protein modules. The composition of these modules is dynamic and might depend on receptor stimulation, the proteome of a given cellular context, the subcellular localization of receptor-associated modules, the formation of GPCR oligomers and the variation of expression levels of components of these modules under physiological, for example circadian rhythm, or pathological conditions. The current article will highlight the importance of GPCR-associated protein modules as a biochemical basis for signaling specificity.
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Affiliation(s)
- Pascal Maurice
- Inserm, U1016, Institut Cochin, 22 rue Méchain, 75014, Paris, France
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Chen T, Zhang L, Qu Y, Huo K, Jiang X, Fei Z. The selective mGluR5 agonist CHPG protects against traumatic brain injury in vitro and in vivo via ERK and Akt pathway. Int J Mol Med 2011; 29:630-6. [PMID: 22211238 PMCID: PMC3577346 DOI: 10.3892/ijmm.2011.870] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2011] [Accepted: 10/27/2011] [Indexed: 12/31/2022] Open
Abstract
Group I metabotropic glutamate receptors (mGluRs) have been implicated in the pathophysiology of central nervous system injury, but the role of mGluR5 in traumatic brain injury (TBI) remains unclear. In the present study, we investigated the neuroprotective potency of (R,S)-2-chloro-5-hydroxyphenylglycine (CHPG), a selective mGluR5 agonist, for protecting against TBI in both in vitro and in vivo models. Primary cortical neurons were treated with 1 mM CHPG in an in vitro preparation 30 min before TBI, and 250 nM CHPG was injected into the right lateral ventricle of rats 30 min before TBI was induced in in vivo studies. The results showed that CHPG significantly attenuated lactate dehydrogenase (LDH) release and neuronal apoptosis and reduced lesion volume. Compared to the control or vehicle group, the phosphorylation levels of extracellular signal-regulated kinase (ERK) and Akt were increased in the presence of CHPG, even following the induction of TBI. Furthermore, treatment with either the ERK inhibitor PD98059 or Akt inhibitor LY294002 partially reversed the CHPG's neuroprotective effects. These data suggest that CHPG minimizes brain damage after induction of TBI both in vitro and in vivo, and that these protective effects were possibly mediated by activation of the ERK and Akt signaling pathways. Thus, potentiating mGluR5 activity with selective agonists such as CHPG may be useful for the treatment of traumatic brain injury.
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Affiliation(s)
- Tao Chen
- Department of Neurosurgery, Xijing Institute of Clinical Neuroscience, Xijing Hospital, Fourth Military Medical University, Xi'an, Shannxi 710032, PR China
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48
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Cleva RM, Hicks MP, Gass JT, Wischerath KC, Plasters ET, Widholm JJ, Olive MF. mGluR5 positive allosteric modulation enhances extinction learning following cocaine self-administration. Behav Neurosci 2011; 125:10-9. [PMID: 21319882 DOI: 10.1037/a0022339] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Extinction of classically and instrumentally conditioned behaviors, such as conditioned fear and drug-seeking behavior, is a process of active learning, and recent studies indicate that potentiation of glutamatergic transmission facilitates extinction learning. In this study, the authors investigated the effects of the Type-5 metabotropic glutamate receptors (mGluR5) positive allosteric modulator 3-cyano-N-(1,3-diphenyl-1H-pyrazol-5-yl)benzamide (CDPPB) on the extinction of cocaine-seeking behavior in rats with a history of intravenous cocaine self-administration. To assess its effects on acquisition and consolidation of extinction learning, CDPPB (60 mg/kg) or vehicle was administered either 20 min prior to, or immediately following, each of 10 extinction sessions, respectively. When administered prior to each extinction session, CDPPB produced a significant reduction in the number of active lever presses on all 10 days of extinction training as compared to vehicle-treated animals. When administered following each extinction session, a significant reduction in the number of active lever presses was observed on the 2nd through 10th day of extinction. Both treatment regimens also reduced the number of extinction-training sessions required to meet extinction criteria. Pre- or postextinction-training administration of CDPPB did not alter responding on the inactive lever and had no effects on open field locomotor activity. These data indicate that positive allosteric modulation of mGluR5 receptors facilitates the acquisition and consolidation of extinction learning following cocaine self-administration and may provide a novel pharmacological approach to enhancing extinction learning when combined with cue exposure therapy for the treatment of cocaine addiction.
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Affiliation(s)
- Richard M Cleva
- Center for Drug and Alcohol Programs, Department of Psychiatry and Behavioral Sciences, Medical University of South Carolina, SC, USA
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49
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Ji G, Neugebauer V. Pain-related deactivation of medial prefrontal cortical neurons involves mGluR1 and GABA(A) receptors. J Neurophysiol 2011; 106:2642-52. [PMID: 21880942 PMCID: PMC3214095 DOI: 10.1152/jn.00461.2011] [Citation(s) in RCA: 123] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2011] [Accepted: 08/29/2011] [Indexed: 11/22/2022] Open
Abstract
Pain-related hyperactivity in the amygdala leads to deactivation of the medial prefrontal cortex (mPFC) and decision-making deficits. The mechanisms of pain-related inhibition of the mPFC are not yet known. Here, we used extracellular single-unit recordings of prelimbic mPFC neurons to determine the role of GABA(A) receptors and metabotropic glutamate receptor (mGluR) subtypes, mGluR1 and mGluR5, in pain-related activity changes of mPFC neurons. Background and evoked activity of mPFC neurons decreased after arthritis induction. To determine pain-related changes, the same neuron was recorded continuously before and after induction of arthritis in one knee joint by intra-articular injection of kaolin/carrageenan. Stereotaxic administration of a GABA(A) receptor antagonist {[R-(R*,S*)]-5-(6,8-dihydro-8-oxofuro[3,4-e]-1,3-benzodioxol-6-yl)-5,6,7,8-tetrahydro-6,6-dimethyl-1,3-dioxolo[4,5-g]isoquinolinium iodide (bicuculline)} into the mPFC by microdialysis reversed pain-related inhibition, whereas offsite injections into the adjacent anterior cingulate cortex had no or opposite effects on prelimbic mPFC neurons. A selective mGluR1/5 agonist [(S)-3,5-dihydroxyphenylglycine (DHPG)] inhibited background and evoked activity under normal conditions through a GABAergic mechanism, because the inhibitory effect was blocked with bicuculline. In the arthritis pain state, DHPG, alone or in the presence of bicuculline, had no effect. Consistent with the involvement of mGluR1 in pain-related inhibition of the mPFC, a selective mGluR1 antagonist [(S)-(+)-α-amino-4-carboxy-2-methylbenzeneacetic acid] reversed the pain-related decrease of background and evoked activity of mPFC neurons in arthritis, whereas a selective mGluR5 antagonist [2-methyl-6-(phenylethynyl)pyridine hydrochloride] had no effect. The mGluR antagonists had no effect under normal conditions. We interpret our data to suggest that pain-related inhibition of mPFC neurons in the arthritis model depends on mGluR1-mediated endogenous activation of GABA(A) receptors. Exogenous activation of mGluR1/5 produces GABAergic inhibition under normal conditions. Restoring normal activity in the mPFC may be a therapeutic strategy to improve cognitive deficits associated with persistent pain.
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Affiliation(s)
- Guangchen Ji
- Dept. of Neuroscience and Cell Biology, The Univ. of Texas Medical Branch, 301 Univ. Blvd., Galveston, TX 77555-1069, USA
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Mehta MV, Gandal MJ, Siegel SJ. mGluR5-antagonist mediated reversal of elevated stereotyped, repetitive behaviors in the VPA model of autism. PLoS One 2011; 6:e26077. [PMID: 22016815 PMCID: PMC3189241 DOI: 10.1371/journal.pone.0026077] [Citation(s) in RCA: 124] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2011] [Accepted: 09/19/2011] [Indexed: 01/22/2023] Open
Abstract
Autism spectrum disorders (ASD) are highly disabling developmental disorders with a population prevalence of 1–3%. Despite a strong genetic etiology, there are no current therapeutic options that target the core symptoms of ASD. Emerging evidence suggests that dysfunction of glutamatergic signaling, in particular through metabotropic glutamate receptor 5 (mGluR5) receptors, may contribute to phenotypic deficits and may be appropriate targets for pharmacologic intervention. This study assessed the therapeutic potential of 2-methyl-6-phenylethyl-pyrididine (MPEP), an mGluR5-receptor antagonist, on repetitive and anxiety-like behaviors in the valproic acid (VPA) mouse model of autism. Mice were exposed prenatally on day E13 to VPA and assessed for repetitive self-grooming and marble burying behaviors as adults. Anxiety-like behavior and locomotor activity were measured in an open-field. VPA-exposed mice displayed increased repetitive and anxiety-like behaviors, consistent with previously published results. Across both marble burying and self-grooming assays, MPEP significantly reduced repetitive behaviors in VPA-treated mice, but had no effect on locomotor activity. These results are consistent with emerging preclinical literature that mGluR5-antagonists may have therapeutic efficacy for core symptoms of autism.
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Affiliation(s)
- Mili V. Mehta
- Translational Neuroscience Program, Department of Psychiatry, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Michael J. Gandal
- Translational Neuroscience Program, Department of Psychiatry, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Steven J. Siegel
- Translational Neuroscience Program, Department of Psychiatry, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
- * E-mail:
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