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Gumpper RH, Roth BL. Psychedelics: preclinical insights provide directions for future research. Neuropsychopharmacology 2024; 49:119-127. [PMID: 36932180 PMCID: PMC10700551 DOI: 10.1038/s41386-023-01567-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/26/2022] [Revised: 01/30/2023] [Accepted: 02/28/2023] [Indexed: 03/19/2023]
Abstract
Recently, psychedelics have emerged as promising therapeutics for numerous neuropsychiatric disorders. While their potential in the clinic has yet to be fully elucidated, understanding their molecular and biological mechanisms is imperative as these compounds are becoming widely used both in therapeutic and recreational contexts. This review examines the current understanding of basic biology, pharmacology, and structural biology in an attempt to reveal both the knowns and unknowns within the field.
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Affiliation(s)
- Ryan H Gumpper
- Department of Pharmacology, UNC School of Medicine, Chapel Hill, NC, 27514, USA
| | - Bryan L Roth
- Department of Pharmacology, UNC School of Medicine, Chapel Hill, NC, 27514, USA.
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2
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Kolasa M, Faron-Górecka A. Preclinical models of treatment-resistant depression: challenges and perspectives. Pharmacol Rep 2023; 75:1326-1340. [PMID: 37882914 PMCID: PMC10661811 DOI: 10.1007/s43440-023-00542-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2023] [Revised: 10/06/2023] [Accepted: 10/06/2023] [Indexed: 10/27/2023]
Abstract
Treatment-resistant depression (TRD) is a subgroup of major depressive disorder in which the use of classical antidepressant treatments fails to achieve satisfactory treatment results. Although there are various definitions and grading models for TRD, common criteria for assessing TRD have still not been established. However, a common feature of any TRD model is the lack of response to at least two attempts at antidepressant pharmacotherapy. The causes of TRD are not known; nevertheless, it is estimated that even 60% of TRD patients are so-called pseudo-TRD patients, in which multiple biological factors, e.g., gender, age, and hormonal disturbances are concomitant with depression and involved in antidepressant drug resistance. Whereas the phenomenon of TRD is a complex disorder difficult to diagnose and successfully treat, the search for new treatment strategies is a significant challenge of modern pharmacology. It seems that despite the complexity of the TRD phenomenon, some useful animal models of TRD meet the construct, the face, and the predictive validity criteria. Based on the literature and our own experiences, we will discuss the utility of animals exposed to the stress paradigm (chronic mild stress, CMS), and the Wistar Kyoto rat strain representing an endogenous model of TRD. In this review, we will focus on reviewing research on existing and novel therapies for TRD, including ketamine, deep brain stimulation (DBS), and psychedelic drugs in the context of preclinical studies in representative animal models of TRD.
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Affiliation(s)
- Magdalena Kolasa
- Department of Pharmacology, Maj Institute of Pharmacology, Polish Academy of Sciences, Smętna 12, 31-343, Kraków, Poland
| | - Agata Faron-Górecka
- Department of Pharmacology, Maj Institute of Pharmacology, Polish Academy of Sciences, Smętna 12, 31-343, Kraków, Poland.
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3
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Sampedro-Viana D, Cañete T, Mourelo L, Oliveras I, Peralta-Vallejo N, Tobeña A, Fernández-Teruel A. Low prepulse inhibition predicts lower social interaction, impaired spatial working memory, reference memory and cognitive flexibility in genetically heterogeneous rats. Physiol Behav 2023; 271:114355. [PMID: 37734470 DOI: 10.1016/j.physbeh.2023.114355] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2023] [Revised: 09/15/2023] [Accepted: 09/18/2023] [Indexed: 09/23/2023]
Abstract
The "Genetically Heterogeneous National Institutes of Health (NIHHS)" stock rat (hereafter HS) shows a wide phenotypic variation, as a result of having been derived from eight inbred rat strains. Thus, these rats may be a conceivable parallel model of a healthy human sample. In order to evaluate whether HS rats have face validity as an animal model of schizophrenia-relevant features, it should be demonstrated that they present behavioural traits that may model negative and cognitive symptoms of the disorder. Previous studies on HS rats have shown that prepulse inhibition (PPI, a measure of sensorimotor gating processes), which is impaired in schizophrenic patients, is correlated with their working memory performance. In this study, we evaluated whether low PPI in the HS stock rat predicts impairments of spatial working memory (SWM), spatial reference memory and cognitive flexibility in the Morris water maze (MWM) test, and we evaluated HS rats for social interaction (SI) in a social investigation task. HS rats were stratified into 2 different groups according to their PPI scores, i.e. low- and high-PPI. In the SI task, low-PPI rats showed decreased social behaviour compared to high-PPI rats. In addition, relative to high-PPI HS rats, the low-PPI group displayed poorer SWM performance, impaired cognitive flexibility (in a reversal task) and worsened long-term spatial memory. Such differential behaviours in social and cognitive paradigms provide evidence on the face validity of low-PPI HS rats as a model of negative-like and cognitive schizophrenia-relevant traits.
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Affiliation(s)
- D Sampedro-Viana
- Medical Psychology Unit, Department of Psychiatry & Forensic Medicine, Institute of Neurosciences, Autonomous University of Barcelona, 08193, Bellaterra, Barcelona, Spain
| | - T Cañete
- Medical Psychology Unit, Department of Psychiatry & Forensic Medicine, Institute of Neurosciences, Autonomous University of Barcelona, 08193, Bellaterra, Barcelona, Spain
| | - L Mourelo
- Medical Psychology Unit, Department of Psychiatry & Forensic Medicine, Institute of Neurosciences, Autonomous University of Barcelona, 08193, Bellaterra, Barcelona, Spain
| | - I Oliveras
- Medical Psychology Unit, Department of Psychiatry & Forensic Medicine, Institute of Neurosciences, Autonomous University of Barcelona, 08193, Bellaterra, Barcelona, Spain
| | - N Peralta-Vallejo
- Medical Psychology Unit, Department of Psychiatry & Forensic Medicine, Institute of Neurosciences, Autonomous University of Barcelona, 08193, Bellaterra, Barcelona, Spain
| | - A Tobeña
- Medical Psychology Unit, Department of Psychiatry & Forensic Medicine, Institute of Neurosciences, Autonomous University of Barcelona, 08193, Bellaterra, Barcelona, Spain
| | - A Fernández-Teruel
- Medical Psychology Unit, Department of Psychiatry & Forensic Medicine, Institute of Neurosciences, Autonomous University of Barcelona, 08193, Bellaterra, Barcelona, Spain.
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4
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Ubhayarathna M, Langmead CJ, Diepenhorst NA, Stewart GD. Molecular and structural insights into the 5-HT 2C receptor as a therapeutic target for substance use disorders. Br J Pharmacol 2023. [PMID: 37679998 DOI: 10.1111/bph.16233] [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: 11/03/2022] [Revised: 08/07/2023] [Accepted: 08/09/2023] [Indexed: 09/09/2023] Open
Abstract
Substance use disorder (SUD) is a chronic condition, with maintained abuse of a substance leading to physiological and psychological alterations and often changes in cognitive and social behaviours. Current therapies include psychotherapy coupled with medication; however, high relapse rates reveal the shortcomings of these therapies. The signalling, expression profile, and neurological function of the serotonin 2C receptor (5-HT2C receptor) make it a candidate of interest for the treatment of SUD. Recently, psychedelics, which broadly act at 5-HT2 receptors, have indicated potential for the treatment of SUD, implicating the 5-HT2C receptor. The modern psychedelic movement has rekindled interest in the 5-HT2C receptor, resulting in many new studies, especially structural analyses. This review explores the structural, molecular and cellular mechanisms governing 5-HT2C receptor function in the context of SUD. This provides the basis of the preclinical and clinical evidence for their role in SUD and highlights the potential for future exploration.
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Affiliation(s)
- Maleesha Ubhayarathna
- Drug Discovery Biology and Neuroscience & Mental Health Therapeutic Program Area, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Australia
- ARC Centre for Cryo-electron Microscopy of Membrane Proteins, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Australia
| | - Christopher J Langmead
- Drug Discovery Biology and Neuroscience & Mental Health Therapeutic Program Area, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Australia
- ARC Centre for Cryo-electron Microscopy of Membrane Proteins, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Australia
- Neuromedicines Discovery Centre, Monash University, Parkville, Australia
| | - Natalie A Diepenhorst
- Drug Discovery Biology and Neuroscience & Mental Health Therapeutic Program Area, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Australia
- ARC Centre for Cryo-electron Microscopy of Membrane Proteins, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Australia
| | - Gregory D Stewart
- Drug Discovery Biology and Neuroscience & Mental Health Therapeutic Program Area, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Australia
- ARC Centre for Cryo-electron Microscopy of Membrane Proteins, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Australia
- Neuromedicines Discovery Centre, Monash University, Parkville, Australia
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5
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Vellucci L, Ciccarelli M, Buonaguro EF, Fornaro M, D’Urso G, De Simone G, Iasevoli F, Barone A, de Bartolomeis A. The Neurobiological Underpinnings of Obsessive-Compulsive Symptoms in Psychosis, Translational Issues for Treatment-Resistant Schizophrenia. Biomolecules 2023; 13:1220. [PMID: 37627285 PMCID: PMC10452784 DOI: 10.3390/biom13081220] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2023] [Revised: 07/24/2023] [Accepted: 07/31/2023] [Indexed: 08/27/2023] Open
Abstract
Almost 25% of schizophrenia patients suffer from obsessive-compulsive symptoms (OCS) considered a transdiagnostic clinical continuum. The presence of symptoms pertaining to both schizophrenia and obsessive-compulsive disorder (OCD) may complicate pharmacological treatment and could contribute to lack or poor response to the therapy. Despite the clinical relevance, no reviews have been recently published on the possible neurobiological underpinnings of this comorbidity, which is still unclear. An integrative view exploring this topic should take into account the following aspects: (i) the implication for glutamate, dopamine, and serotonin neurotransmission as demonstrated by genetic findings; (ii) the growing neuroimaging evidence of the common brain regions and dysfunctional circuits involved in both diseases; (iii) the pharmacological modulation of dopaminergic, serotoninergic, and glutamatergic systems as current therapeutic strategies in schizophrenia OCS; (iv) the recent discovery of midbrain dopamine neurons and dopamine D1- and D2-like receptors as orchestrating hubs in repetitive and psychotic behaviors; (v) the contribution of N-methyl-D-aspartate receptor subunits to both psychosis and OCD neurobiology. Finally, we discuss the potential role of the postsynaptic density as a structural and functional hub for multiple molecular signaling both in schizophrenia and OCD pathophysiology.
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Affiliation(s)
| | | | | | | | | | | | | | | | - Andrea de Bartolomeis
- Section of Psychiatry, Laboratory of Translational and Molecular Psychiatry and Unit of Treatment-Resistant Psychosis, Department of Neuroscience, Reproductive Sciences and Dentistry University Medical School of Naples “Federico II”, Via Pansini 5, 80131 Naples, Italy
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6
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Pittaluga A, Grilli M, Olivero G. Progress in metamodulation and receptor-receptor interaction: from physiology to pathology and therapy. Neuropharmacology 2023:109639. [PMID: 37343628 DOI: 10.1016/j.neuropharm.2023.109639] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/23/2023]
Abstract
The organization and the role of receptor-receptor interaction (RRI) and metamodulation in physiological conditions have been extensively analyzed and discussed. In this Special Issue of Neuropharmacology, we review recent advances in the understanding of the RRI and the mechanisms underlying its adaptation that could be relevant to the etiopathogenesis of central neuropsychiatric disorders, as well as to the development of new therapeutic approaches to control the activity and to restore the physiological functions, posing the basis for new targeted pharmacological interventions.
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Affiliation(s)
- Anna Pittaluga
- Department of Pharmacy, University of Genoa, Viale Cembrano 4, 16148 Genoa, Italy; Inter-University Center for the Promotion of the 3Rs Principles in Teaching & Research (Centro 3R), 16148 Genoa, Italy; IRCCS Ospedale Policlinico San Martino, 16145 Genoa, Italy.
| | - Massimo Grilli
- Department of Pharmacy, University of Genoa, Viale Cembrano 4, 16148 Genoa, Italy; Inter-University Center for the Promotion of the 3Rs Principles in Teaching & Research (Centro 3R), 16148 Genoa, Italy
| | - Guendalina Olivero
- Department of Pharmacy, University of Genoa, Viale Cembrano 4, 16148 Genoa, Italy
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Saha S, González-Maeso J. The crosstalk between 5-HT 2AR and mGluR2 in schizophrenia. Neuropharmacology 2023; 230:109489. [PMID: 36889432 PMCID: PMC10103009 DOI: 10.1016/j.neuropharm.2023.109489] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2023] [Revised: 02/26/2023] [Accepted: 03/05/2023] [Indexed: 03/08/2023]
Abstract
Schizophrenia is a severe brain disorder that usually produces a lifetime of disability. First generation or typical antipsychotics such as haloperidol and second generation or atypical antipsychotics such as clozapine and risperidone remain the current standard for schizophrenia treatment. In some patients with schizophrenia, antipsychotics produce complete remission of positive symptoms, such as hallucinations and delusions. However, antipsychotic drugs are ineffective against cognitive deficits and indeed treated schizophrenia patients have small improvements or even deterioration in several cognitive domains. This underlines the need for novel and more efficient therapeutic targets for schizophrenia treatment. Serotonin and glutamate have been identified as key parts of two neurotransmitter systems involved in fundamental brain processes. Serotonin (or 5-hydroxytryptamine) 5-HT2A receptor (5-HT2AR) and metabotropic glutamate 2 receptor (mGluR2) are G protein-coupled receptors (GPCRs) that interact at epigenetic and functional levels. These two receptors can form GPCR heteromeric complexes through which their pharmacology, function and trafficking becomes affected. Here we review past and current research on the 5-HT2AR-mGluR2 heterocomplex and its potential implication in schizophrenia and antipsychotic drug action. This article is part of the Special Issue on "The receptor-receptor interaction as a new target for therapy".
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Affiliation(s)
- Somdatta Saha
- Department of Physiology and Biophysics, Virginia Commonwealth University School of Medicine, Richmond, VA, 23298, USA
| | - Javier González-Maeso
- Department of Physiology and Biophysics, Virginia Commonwealth University School of Medicine, Richmond, VA, 23298, USA.
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8
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Domanegg K, Sommer WH, Meinhardt MW. Psychedelic Targeting of Metabotropic Glutamate Receptor 2 and Its Implications for the Treatment of Alcoholism. Cells 2023; 12:963. [PMID: 36980303 PMCID: PMC10047550 DOI: 10.3390/cells12060963] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2023] [Revised: 03/16/2023] [Accepted: 03/20/2023] [Indexed: 03/30/2023] Open
Abstract
Alcohol abuse is a leading risk factor for the public health burden worldwide. Approved pharmacotherapies have demonstrated limited effectiveness over the last few decades in treating alcohol use disorders (AUD). New therapeutic approaches are therefore urgently needed. Historical and recent clinical trials using psychedelics in conjunction with psychotherapy demonstrated encouraging results in reducing heavy drinking in AUD patients, with psilocybin being the most promising candidate. While psychedelics are known to induce changes in gene expression and neuroplasticity, we still lack crucial information about how this specifically counteracts the alterations that occur in neuronal circuits throughout the course of addiction. This review synthesizes well-established knowledge from addiction research about pathophysiological mechanisms related to the metabotropic glutamate receptor 2 (mGlu2), with findings and theories on how mGlu2 connects to the major signaling pathways induced by psychedelics via serotonin 2A receptors (2AR). We provide literature evidence that mGlu2 and 2AR are able to regulate each other's downstream signaling pathways, either through monovalent crosstalk or through the formation of a 2AR-mGlu2 heteromer, and highlight epigenetic mechanisms by which 2ARs can modulate mGlu2 expression. Lastly, we discuss how these pathways might be targeted therapeutically to restore mGlu2 function in AUD patients, thereby reducing the propensity to relapse.
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Affiliation(s)
- Kevin Domanegg
- Institute of Psychopharmacology, Central Institute of Mental Health, Medical Faculty Mannheim, University of Heidelberg, 69115 Heidelberg, Germany
| | - Wolfgang H. Sommer
- Institute of Psychopharmacology, Central Institute of Mental Health, Medical Faculty Mannheim, University of Heidelberg, 69115 Heidelberg, Germany
- Bethanien Hospital for Psychiatry, Psychosomatics, and Psychotherapy Greifswald, 17489 Greifswald, Germany
| | - Marcus W. Meinhardt
- Institute of Psychopharmacology, Central Institute of Mental Health, Medical Faculty Mannheim, University of Heidelberg, 69115 Heidelberg, Germany
- Department of Molecular Neuroimaging, Central Institute of Mental Health, Medical Faculty Mannheim, University of Heidelberg, 69115 Heidelberg, Germany
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9
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Johnston JN, Kadriu B, Allen J, Gilbert JR, Henter ID, Zarate CA. Ketamine and serotonergic psychedelics: An update on the mechanisms and biosignatures underlying rapid-acting antidepressant treatment. Neuropharmacology 2023; 226:109422. [PMID: 36646310 PMCID: PMC9983360 DOI: 10.1016/j.neuropharm.2023.109422] [Citation(s) in RCA: 17] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2022] [Revised: 01/09/2023] [Accepted: 01/12/2023] [Indexed: 01/15/2023]
Abstract
The discovery of ketamine as a rapid-acting antidepressant spurred significant research to understand its underlying mechanisms of action and to identify other novel compounds that may act similarly. Serotonergic psychedelics (SPs) have shown initial promise in treating depression, though the challenge of conducting randomized controlled trials with SPs and the necessity of long-term clinical observation are important limitations. This review summarizes the similarities and differences between the psychoactive effects associated with both ketamine and SPs and the mechanisms of action of these compounds, with a focus on the monoaminergic, glutamatergic, gamma-aminobutyric acid (GABA)-ergic, opioid, and inflammatory systems. Both molecular and neuroimaging aspects are considered. While their main mechanisms of action differ-SPs increase serotonergic signaling while ketamine is a glutamatergic modulator-evidence suggests that the downstream mechanisms of action of both ketamine and SPs include mechanistic target of rapamycin complex 1 (mTORC1) signaling and downstream GABAA receptor activity. The similarities in downstream mechanisms may explain why ketamine, and potentially SPs, exert rapid-acting antidepressant effects. However, research on SPs is still in its infancy compared to the ongoing research that has been conducted with ketamine. For both therapeutics, issues with regulation and proper controls should be addressed before more widespread implementation. This article is part of the Special Issue on "Ketamine and its Metabolites".
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Affiliation(s)
- Jenessa N Johnston
- Experimental Therapeutics and Pathophysiology Branch, National Institute of Mental Health, National Institutes of Health, Bethesda, MD, USA.
| | - Bashkim Kadriu
- Experimental Therapeutics and Pathophysiology Branch, National Institute of Mental Health, National Institutes of Health, Bethesda, MD, USA.
| | - Josh Allen
- The Alfred Centre, Department of Neuroscience, Monash University, Melbourne, Victoria, Australia.
| | - Jessica R Gilbert
- Experimental Therapeutics and Pathophysiology Branch, National Institute of Mental Health, National Institutes of Health, Bethesda, MD, USA.
| | - Ioline D Henter
- Experimental Therapeutics and Pathophysiology Branch, National Institute of Mental Health, National Institutes of Health, Bethesda, MD, USA.
| | - Carlos A Zarate
- Experimental Therapeutics and Pathophysiology Branch, National Institute of Mental Health, National Institutes of Health, Bethesda, MD, USA.
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Kwan C, Kang W, Kim E, Belliveau S, Frouni I, Huot P. Metabotropic glutamate receptors in Parkinson's disease. INTERNATIONAL REVIEW OF NEUROBIOLOGY 2023; 168:1-31. [PMID: 36868628 DOI: 10.1016/bs.irn.2022.10.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Parkinson's disease (PD) is a complex disorder that leads to alterations in multiple neurotransmitter systems, notably glutamate. As such, several drugs acting at glutamatergic receptors have been assessed to alleviate the manifestation of PD and treatment-related complications, culminating with the approval of the N-methyl-d-aspartate (NMDA) antagonist amantadine for l-3,4-dihydroxyphenylalanine (l-DOPA)-induced dyskinesia. Glutamate elicits its actions through several ionotropic and metabotropic (mGlu) receptors. There are 8 sub-types of mGlu receptors, with sub-types 4 (mGlu4) and 5 (mGlu5) modulators having been tested in the clinic for endpoints pertaining to PD, while sub-types 2 (mGlu2) and 3 (mGlu3) have been investigated in pre-clinical settings. In this book chapter, we provide an overview of mGlu receptors in PD, with a focus on mGlu5, mGlu4, mGlu2 and mGlu3 receptors. For each sub-type, we review, when applicable, their anatomical localization and possible mechanisms underlying their efficacy for specific disease manifestation or treatment-induced complications. We then summarize the findings of pre-clinical studies and clinical trials with pharmacological agents and discuss the potential strengths and limitations of each target. We conclude by offering some perspectives on the potential use of mGlu modulators in the treatment of PD.
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Affiliation(s)
- Cynthia Kwan
- Neurodegenerative Disease Group, Montreal Neurological Institute-Hospital (The Neuro), Montreal, QC, Canada
| | - Woojin Kang
- Neurodegenerative Disease Group, Montreal Neurological Institute-Hospital (The Neuro), Montreal, QC, Canada
| | - Esther Kim
- Neurodegenerative Disease Group, Montreal Neurological Institute-Hospital (The Neuro), Montreal, QC, Canada
| | - Sébastien Belliveau
- Neurodegenerative Disease Group, Montreal Neurological Institute-Hospital (The Neuro), Montreal, QC, Canada
| | - Imane Frouni
- Neurodegenerative Disease Group, Montreal Neurological Institute-Hospital (The Neuro), Montreal, QC, Canada; Département de Pharmacologie et Physiologie, Université de Montréal, Montreal, QC, Canada
| | - Philippe Huot
- Neurodegenerative Disease Group, Montreal Neurological Institute-Hospital (The Neuro), Montreal, QC, Canada; Département de Pharmacologie et Physiologie, Université de Montréal, Montreal, QC, Canada; Department of Neurology and Neurosurgery, McGill University, Montreal, QC, Canada; Movement Disorder Clinic, Division of Neurology, Department of Neurosciences, McGill University Health Centre, Montreal, QC, Canada.
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11
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Molecular Pathways of the Therapeutic Effects of Ayahuasca, a Botanical Psychedelic and Potential Rapid-Acting Antidepressant. Biomolecules 2022; 12:biom12111618. [DOI: 10.3390/biom12111618] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2022] [Revised: 10/27/2022] [Accepted: 10/29/2022] [Indexed: 11/06/2022] Open
Abstract
Ayahuasca is a psychoactive brew traditionally used in indigenous and religious rituals and ceremonies in South America for its therapeutic, psychedelic, and entheogenic effects. It is usually prepared by lengthy boiling of the leaves of the bush Psychotria viridis and the mashed stalks of the vine Banisteriopsis caapi in water. The former contains the classical psychedelic N,N-dimethyltryptamine (DMT), which is thought to be the main psychoactive alkaloid present in the brew. The latter serves as a source for β-carbolines, known for their monoamine oxidase-inhibiting (MAOI) properties. Recent preliminary research has provided encouraging results investigating ayahuasca’s therapeutic potential, especially regarding its antidepressant effects. On a molecular level, pre-clinical and clinical evidence points to a complex pharmacological profile conveyed by the brew, including modulation of serotoninergic, glutamatergic, dopaminergic, and endocannabinoid systems. Its substances also interact with the vesicular monoamine transporter (VMAT), trace amine-associated receptor 1 (TAAR1), and sigma-1 receptors. Furthermore, ayahuasca’s components also seem to modulate levels of inflammatory and neurotrophic factors beneficially. On a biological level, this translates into neuroprotective and neuroplastic effects. Here we review the current knowledge regarding these molecular interactions and how they relate to the possible antidepressant effects ayahuasca seems to produce.
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12
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Caniceiro AB, Bueschbell B, Schiedel AC, Moreira IS. Class A and C GPCR Dimers in Neurodegenerative Diseases. Curr Neuropharmacol 2022; 20:2081-2141. [PMID: 35339177 PMCID: PMC9886835 DOI: 10.2174/1570159x20666220327221830] [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: 09/14/2021] [Revised: 02/21/2022] [Accepted: 03/23/2022] [Indexed: 11/22/2022] Open
Abstract
Neurodegenerative diseases affect over 30 million people worldwide with an ascending trend. Most individuals suffering from these irreversible brain damages belong to the elderly population, with onset between 50 and 60 years. Although the pathophysiology of such diseases is partially known, it remains unclear upon which point a disease turns degenerative. Moreover, current therapeutics can treat some of the symptoms but often have severe side effects and become less effective in long-term treatment. For many neurodegenerative diseases, the involvement of G proteincoupled receptors (GPCRs), which are key players of neuronal transmission and plasticity, has become clearer and holds great promise in elucidating their biological mechanism. With this review, we introduce and summarize class A and class C GPCRs, known to form heterodimers or oligomers to increase their signalling repertoire. Additionally, the examples discussed here were shown to display relevant alterations in brain signalling and had already been associated with the pathophysiology of certain neurodegenerative diseases. Lastly, we classified the heterodimers into two categories of crosstalk, positive or negative, for which there is known evidence.
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Affiliation(s)
- Ana B. Caniceiro
- Center for Neuroscience and Cell Biology, University of Coimbra, 3004-504 Coimbra, Portugal; ,These authors contributed equally to this work.
| | - Beatriz Bueschbell
- PhD Programme in Experimental Biology and Biomedicine, Institute for Interdisciplinary Research (IIIUC), University of Coimbra, Casa Costa Alemão, 3030-789 Coimbra, Portugal; ,These authors contributed equally to this work.
| | - Anke C. Schiedel
- Department of Pharmaceutical & Medicinal Chemistry, Pharmaceutical Institute, University of Bonn, D-53121 Bonn, Germany;
| | - Irina S. Moreira
- University of Coimbra, Department of Life Sciences, Calçada Martim de Freitas, 3000-456 Coimbra, Portugal; ,Center for Neuroscience and Cell Biology, Center for Innovative Biomedicine and Biotechnology, 3004-504 Coimbra, Portugal,Address correspondence to this author at the Center for Neuroscience and Cell Biology, Center for Innovative Biomedicine and Biotechnology, 3004-504 Coimbra, Portugal; E-mail:
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13
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Presynaptic 5-HT2A-mGlu2/3 Receptor–Receptor Crosstalk in the Prefrontal Cortex: Metamodulation of Glutamate Exocytosis. Cells 2022; 11:cells11193035. [PMID: 36230998 PMCID: PMC9562019 DOI: 10.3390/cells11193035] [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: 08/19/2022] [Revised: 09/19/2022] [Accepted: 09/26/2022] [Indexed: 12/02/2022] Open
Abstract
The glutamatergic nerve endings of a rat prefrontal cortex (PFc) possess presynaptic 5-HT2A heteroreceptors and mGlu2/3 autoreceptors, whose activation inhibits glutamate exocytosis, and is measured as 15 mM KCl-evoked [3H]D-aspartate ([3H]D-asp) release (which mimics glutamate exocytosis). The concomitant activation of the two receptors nulls their inhibitory activities, whereas blockade of the 5-HT2A heteroreceptors with MDL11,939 (1 μM) strengthens the inhibitory effect elicited by the mGlu2/3 receptor agonist LY329268 (1 μM). 5-HT2A receptor antagonists (MDL11,939; ketanserin; trazodone) amplify the impact of low (3 nM) LY379268. Clozapine (0.1–10 μM) mimics the 5-HT2A agonist (±) DOI and inhibits the KCl-evoked [3H]D-asp overflow in a MDL11,939-dependent fashion, but does not modify the (±) DOI-induced effect. mGlu2 and 5-HT2A proteins do not co-immunoprecipitate from synaptosomal lysates, nor does the incubation of PFc synaptosomes with MDL11,939 (1 μM) or clozapine (10 µM) modify the insertion of mGlu2 subunits in synaptosomal plasma membranes. In conclusion, 5-HT2A and mGlu2/3 receptors colocalize, but do not physically associate, in PFc glutamatergic terminals, where they functionally interact in an antagonist-like fashion to control glutamate exocytosis. The mGlu2/3-5-HT2A metamodulation could be relevant to therapy for central neuropsychiatric disorders, including schizophrenia, but also unveil cellular events accounting for their development, which also influence the responsiveness to drugs regimens.
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Nuara SG, Gourdon JC, Huot P. Evaluation of the effects of the mGlu 2/3 antagonist LY341495 on dyskinesia and psychosis-like behaviours in the MPTP-lesioned marmoset. Pharmacol Rep 2022; 74:614-625. [PMID: 35761013 DOI: 10.1007/s43440-022-00378-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2022] [Revised: 06/01/2022] [Accepted: 06/05/2022] [Indexed: 11/29/2022]
Abstract
BACKGROUND We have previously demonstrated that the metabotropic glutamate 2 and 3 (mGlu2/3) antagonist LY341495 reverses the anti-dyskinetic and anti-psychotic benefits conferred by mGlu2 activation and serotonin 2A (5-HT2A) antagonism. Here, we hypothesised that a higher dose of LY341495, associated with a higher antagonistic effect at mGlu3 receptors, would result in a reduction of the reversal of mGlu2 activation and 5-HT2A blockade on dyskinesia, in the 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-lesioned marmoset. METHODS After induction of parkinsonism with MPTP, marmosets entered 3 streams of experiments, in which the following treatments were administered, in combination with l-3,4-dihydroxyphenylalanine (L-DOPA), after which dyskinesia, psychosis-like behaviours (PLBs) and parkinsonism were rated: 1. vehicle/vehicle, LY354740 (mGlu2/3 orthosteric agonist)/vehicle, LY354740/LY341495 1 mg/kg and LY354740/LY341495 3 mg/kg; 2. vehicle/vehicle, LY487379 (mGlu2 positive allosteric modulator)/vehicle, LY487379/LY341495 1 mg/kg and LY487379/LY341495 3 mg/kg; 3. vehicle/vehicle, EMD-281,014 (5-HT2A antagonist)/vehicle, EMD-281,014/LY341495 1 mg/kg and EMD-281,014/LY341495 3 mg/kg. RESULTS Each of LY354740, LY487379 and EMD-281,014 reduced the severity of L-DOPA-induced dyskinesia, by 55%, 39% and 40%, respectively (all p < 0.001), as well as the severity of PLBs, by 48%, 36% and 41%, respectively (all p < 0.001). Adding LY341495 1 and 3 mg/kg to each of LY354740, LY487379 and EMD-281,014 resulted in a dose-dependent reversal of their anti-dyskinetic and anti-psychotic actions. No effect on the anti-parkinsonian action of L-DOPA was noted with any treatment combination. CONCLUSION These results suggest that an antagonistic effect at mGlu3 receptors may not be sufficient to overcome the deleterious effect of mGlu2 blockade on dyskinesia in PD. It remains to be seen whether similar effects would have been obtained with a selective mGlu3 antagonist.
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Affiliation(s)
- Stephen G Nuara
- Comparative Medicine and Animal Resource Centre, McGill University, Montreal, QC, Canada
| | - Jim C Gourdon
- Comparative Medicine and Animal Resource Centre, McGill University, Montreal, QC, Canada
| | - Philippe Huot
- Neurodegenerative Disease Group, Montreal Neurological Institute-Hospital (The Neuro), 3801 University St, Montreal, QC, H3A 2B4, Canada. .,Department of Neurology and Neurosurgery, McGill University, Montreal, QC, Canada. .,Division of Neurology, Department of Neurosciences, Movement Disorder Clinic, McGill University Health Centre, Montreal, QC, Canada.
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15
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James E, Keppler J, L Robertshaw T, Sessa B. N,N-dimethyltryptamine and Amazonian ayahuasca plant medicine. Hum Psychopharmacol 2022; 37:e2835. [PMID: 35175662 PMCID: PMC9286861 DOI: 10.1002/hup.2835] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/06/2021] [Revised: 01/13/2022] [Accepted: 01/26/2022] [Indexed: 12/12/2022]
Abstract
OBJECTIVE Reports have indicated possible uses of ayahuasca for the treatment of conditions including depression, addictions, post-traumatic stress disorder, anxiety and specific psychoneuroendocrine immune system pathologies. The article assesses potential ayahuasca and N,N-dimethyltryptamine (DMT) integration with contemporary healthcare. The review also seeks to provide a summary of selected literature regarding the mechanisms of action of DMT and ayahuasca; and assess to what extent the state of research can explain reports of unusual phenomenology. DESIGN A narrative review. RESULTS Compounds in ayahuasca have been found to bind to serotonergic receptors, glutaminergic receptors, sigma-1 receptors, trace amine-associated receptors, and modulate BDNF expression and the dopaminergic system. Subjective effects are associated with increased delta and theta oscillations in amygdala and hippocampal regions, decreased alpha wave activity in the default mode network, and stimulations of vision-related brain regions particularly in the visual association cortex. Both biological processes and field of consciousness models have been proposed to explain subjective effects of DMT and ayahuasca, however, the evidence supporting the proposed models is not sufficient to make confident conclusions. Ayahuasca plant medicine and DMT represent potentially novel treatment modalities. CONCLUSIONS Further research is required to clarify the mechanisms of action and develop treatments which can be made available to the general public. Integration between healthcare research institutions and reputable practitioners in the Amazon is recommended.
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Affiliation(s)
- Edward James
- School of Pharmacy and Pharmaceutical SciencesCardiff UniversityCardiffUK
| | | | | | - Ben Sessa
- Centre for NeuropsychopharmacologyDivision of Brain SciencesFaculty of MedicineImperial College LondonLondonUK
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16
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Liu X, Zhu H, Gao H, Tian X, Tan B, Su R. G s signaling pathway distinguishes hallucinogenic and nonhallucinogenic 5-HT 2AR agonists induced head twitch response in mice. Biochem Biophys Res Commun 2022; 598:20-25. [PMID: 35149433 DOI: 10.1016/j.bbrc.2022.01.113] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2021] [Accepted: 01/28/2022] [Indexed: 11/21/2022]
Abstract
5- HT2A receptor is a member of the family A G-protein-coupled receptor. It is involved in many psychiatric disorders, such as depression, addiction and Parkinson's disease. 5-HT2AR targeted drugs play an important role in regulating cognition, memory, emotion and other physiological function by coupling G proteins, and their most notable function is stimulating the serotonergic hallucination. However, not all 5-HT2AR agonists exhibit hallucinogenic activity, such as lisuride. Molecular mechanisms of these different effects are not well illustrated. This study suggested that 5-HT2AR coupled both Gs and Gq protein under hallucinogenic agonists DOM and 25CN-NBOH stimulation, but nonhallucinogenic agonist lisuride and TBG only activates Gq signaling. Moreover, in head twitch response (HTR) model, we found that cAMP analogs 8-Bromo-cAMP and PDE4 inhibitor Rolipram could increase HTR, while Gs protein inhibitor Melittin could reduce HTR. Collectively, these results revealed that Gs signaling is a key signaling pathway that may distinguish hallucinogenic agonists and nonhallucinogenic agonists.
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Affiliation(s)
- Xiaoqian Liu
- State Key Laboratory of Toxicology and Medical Countermeasures, Beijing Key Laboratory of Neuropsychopharmacology, Beijing Institute of Pharmacology and Toxicology, 27th Taiping Road, Beijing, 100850, China
| | - Huili Zhu
- School of Pharmacy, Yantai University, Yantai, 264005, China
| | - Huan Gao
- State Key Laboratory of Toxicology and Medical Countermeasures, Beijing Key Laboratory of Neuropsychopharmacology, Beijing Institute of Pharmacology and Toxicology, 27th Taiping Road, Beijing, 100850, China; School of Pharmacy, Yantai University, Yantai, 264005, China
| | - Xiangyun Tian
- State Key Laboratory of Toxicology and Medical Countermeasures, Beijing Key Laboratory of Neuropsychopharmacology, Beijing Institute of Pharmacology and Toxicology, 27th Taiping Road, Beijing, 100850, China
| | - Bo Tan
- State Key Laboratory of Toxicology and Medical Countermeasures, Beijing Key Laboratory of Neuropsychopharmacology, Beijing Institute of Pharmacology and Toxicology, 27th Taiping Road, Beijing, 100850, China
| | - Ruibin Su
- State Key Laboratory of Toxicology and Medical Countermeasures, Beijing Key Laboratory of Neuropsychopharmacology, Beijing Institute of Pharmacology and Toxicology, 27th Taiping Road, Beijing, 100850, China.
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17
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Farooq Z, Howell LA, McCormick PJ. Probing GPCR Dimerization Using Peptides. Front Endocrinol (Lausanne) 2022; 13:843770. [PMID: 35909575 PMCID: PMC9329873 DOI: 10.3389/fendo.2022.843770] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/26/2021] [Accepted: 06/10/2022] [Indexed: 11/13/2022] Open
Abstract
G protein-coupled receptors (GPCRs) are the largest class of membrane proteins and the most common and extensively studied pharmacological target. Numerous studies over the last decade have confirmed that GPCRs do not only exist and function in their monomeric form but in fact, have the ability to form dimers or higher order oligomers with other GPCRs, as well as other classes of receptors. GPCR oligomers have become increasingly attractive to investigate as they have the ability to modulate the pharmacological responses of the receptors which in turn, could have important functional roles in diseases, such as cancer and several neurological & neuropsychiatric disorders. Despite the growing evidence in the field of GPCR oligomerisation, the lack of structural information, as well as targeting the 'undruggable' protein-protein interactions (PPIs) involved in these complexes, has presented difficulties. Outside the field of GPCRs, targeting PPIs has been widely studied, with a variety of techniques being investigated; from small-molecule inhibitors to disrupting peptides. In this review, we will demonstrate several physiologically relevant GPCR dimers and discuss an array of strategies and techniques that can be employed when targeting these complexes, as well as provide ideas for future development.
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Affiliation(s)
- Zara Farooq
- Centre for Endocrinology, William Harvey Research Institute, Bart’s and The London School of Medicine and Dentistry, Queen Mary University of London, Charterhouse Square, London, United Kingdom
- Department of Chemistry, School of Physical and Chemical Sciences, Queen Mary University of London, Mile End Road, London, United Kingdom
| | - Lesley A. Howell
- Department of Chemistry, School of Physical and Chemical Sciences, Queen Mary University of London, Mile End Road, London, United Kingdom
| | - Peter J. McCormick
- Centre for Endocrinology, William Harvey Research Institute, Bart’s and The London School of Medicine and Dentistry, Queen Mary University of London, Charterhouse Square, London, United Kingdom
- *Correspondence: Peter J. McCormick,
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18
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McCullock TW, Kammermeier PJ. The evidence for and consequences of metabotropic glutamate receptor heterodimerization. Neuropharmacology 2021; 199:108801. [PMID: 34547332 DOI: 10.1016/j.neuropharm.2021.108801] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2021] [Revised: 09/07/2021] [Accepted: 09/17/2021] [Indexed: 12/15/2022]
Abstract
Metabotropic glutamate receptors (mGluRs) are an essential component of the mammalian central nervous system. These receptors modulate neuronal excitability in response to extracellular glutamate through the activation of intracellular heterotrimeric G proteins. Like most other class C G protein-coupled receptors, mGluRs function as obligate dimer proteins, meaning they need to form dimer complexes before becoming functional receptors. All mGluRs possess the ability to homodimerize, but studies over the past ten years have demonstrated these receptors are also capable of forming heterodimers in specific patterns. These mGluR heterodimers appear to have their own unique biophysical behavior and pharmacology with both native and synthetic compounds with few rules having been identified that allow for prediction of the consequences of any particular mGluR pair forming heterodimers. Here, we review the relevant literature demonstrating the existence and consequences of mGluR heterodimerization. By collecting biophysical and pharmacological data of several mGluR heterodimers we demonstrate the lack of generalizable behavior of these complexes indicating that each individual dimeric pair needs to be investigated independently. Additionally, by combining sequence alignment and structural analysis, we propose that interactions between the β4-A Helix Loop and the D Helix in the extracellular domain of these receptors are the structural components that dictate heterodimerization compatibility. Finally, we discuss the potential implications of mGluR heterodimerization from the viewpoints of further developing our understanding of neuronal physiology and leveraging mGluRs as a therapeutic target for the treatment of pathophysiology.
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Affiliation(s)
- Tyler W McCullock
- Department of Pharmacology and Physiology, University of Rochester Medical Center, 601 Elmwood Ave, Box 711, Rochester, NY, 14642, USA.
| | - Paul J Kammermeier
- Department of Pharmacology and Physiology, University of Rochester Medical Center, 601 Elmwood Ave, Box 711, Rochester, NY, 14642, USA.
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19
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Olivero G, Vergassola M, Cisani F, Roggeri A, Pittaluga A. Presynaptic Release-regulating Metabotropic Glutamate Receptors: An Update. Curr Neuropharmacol 2021; 18:655-672. [PMID: 31775600 PMCID: PMC7457419 DOI: 10.2174/1570159x17666191127112339] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2019] [Revised: 11/15/2019] [Accepted: 11/22/2019] [Indexed: 12/18/2022] Open
Abstract
Metabotropic glutamate (mGlu) receptors represent the largest family of glutamate receptors in mammals and act as fine tuners of the chemical transmission in central nervous system (CNS). In the last decade, results concerning the expression and the subcellular localization of mGlu receptors further clarified their role in physio-pathological conditions. Concomitantly, their pharmacological characterization largely improved thanks to the identification of new compounds (chemical ligands and antibodies recognizing epitopic sequences of the receptor proteins) that allowed to decipher the protein compositions of the naive receptors. mGlu receptors are expressed at the presynaptic site of chemical synapses. Here, they modulate intraterminal enzymatic pathways controlling the migration and the fusion of vesicles to synaptic membranes as well as the phosphorylation of colocalized receptors. Both the control of transmitter exocytosis and the phosphorylation of colocalized receptors elicited by mGlu receptors are relevant events that dictate the plasticity of nerve terminals, and account for the main role of presynaptic mGlu receptors as modulators of neuronal signalling. The role of the presynaptic mGlu receptors in the CNS has been the matter of several studies and this review aims at briefly summarizing the recent observations obtained with isolated nerve endings (we refer to as synaptosomes). We focus on the pharmacological characterization of these receptors and on their receptor-receptor interaction / oligo-dimerization in nerve endings that could be relevant to the development of new therapeutic approaches for the cure of central pathologies.
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Affiliation(s)
| | | | | | | | - Anna Pittaluga
- Department of Pharmacy, University of Genoa, Genoa, Italy.,Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS) Ospedale Policlinico San Martino, Genoa, Italy
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20
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Thibado JK, Tano JY, Lee J, Salas-Estrada L, Provasi D, Strauss A, Marcelo Lamim Ribeiro J, Xiang G, Broichhagen J, Filizola M, Lohse MJ, Levitz J. Differences in interactions between transmembrane domains tune the activation of metabotropic glutamate receptors. eLife 2021; 10:e67027. [PMID: 33880992 PMCID: PMC8102066 DOI: 10.7554/elife.67027] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2021] [Accepted: 04/19/2021] [Indexed: 12/16/2022] Open
Abstract
The metabotropic glutamate receptors (mGluRs) form a family of neuromodulatory G-protein-coupled receptors that contain both a seven-helix transmembrane domain (TMD) and a large extracellular ligand-binding domain (LBD) which enables stable dimerization. Although numerous studies have revealed variability across subtypes in the initial activation steps at the level of LBD dimers, an understanding of inter-TMD interaction and rearrangement remains limited. Here, we use a combination of single molecule fluorescence, molecular dynamics, functional assays, and conformational sensors to reveal that distinct TMD assembly properties drive differences between mGluR subtypes. We uncover a variable region within transmembrane helix 4 (TM4) that contributes to homo- and heterodimerization in a subtype-specific manner and tunes orthosteric, allosteric, and basal activation. We also confirm a critical role for a conserved inter-TM6 interface in stabilizing the active state during orthosteric or allosteric activation. Together this study shows that inter-TMD assembly and dynamic rearrangement drive mGluR function with distinct properties between subtypes.
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Affiliation(s)
- Jordana K Thibado
- Physiology, Biophysics and Systems Biology Graduate Program, Weill Cornell Graduate School of Medical SciencesNew YorkUnited States
| | | | - Joon Lee
- Department of Biochemistry, Weill Cornell MedicineNew YorkUnited States
| | - Leslie Salas-Estrada
- Department of Pharmacological Sciences, Icahn School of Medicine at Mount SinaiNew YorkUnited States
| | - Davide Provasi
- Department of Pharmacological Sciences, Icahn School of Medicine at Mount SinaiNew YorkUnited States
| | - Alexa Strauss
- Tri-Institutional PhD Program in Chemical BiologyNew YorkUnited States
| | | | - Guoqing Xiang
- Department of Biochemistry, Weill Cornell MedicineNew YorkUnited States
| | | | - Marta Filizola
- Department of Pharmacological Sciences, Icahn School of Medicine at Mount SinaiNew YorkUnited States
| | - Martin J Lohse
- Max Delbrück Center for Molecular MedicineBerlinGermany
- ISAR Bioscience InstitutePlanegg-MunichGermany
| | - Joshua Levitz
- Physiology, Biophysics and Systems Biology Graduate Program, Weill Cornell Graduate School of Medical SciencesNew YorkUnited States
- Department of Biochemistry, Weill Cornell MedicineNew YorkUnited States
- Tri-Institutional PhD Program in Chemical BiologyNew YorkUnited States
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21
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Kwan C, Frouni I, Nuara SG, Belliveau S, Kang W, Hamadjida A, Bédard D, Beaudry F, Panisset M, Gourdon JC, Huot P. Combined 5-HT 2A and mGlu 2 modulation for the treatment of dyskinesia and psychosis in Parkinson's disease. Neuropharmacology 2021; 186:108465. [PMID: 33485945 DOI: 10.1016/j.neuropharm.2021.108465] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Revised: 01/09/2021] [Accepted: 01/13/2021] [Indexed: 12/29/2022]
Abstract
Antagonising the serotonin 2A (5-HT2A) receptor is an efficacious way to alleviate dyskinesia and psychosis in Parkinson's disease (PD). However, previous research indicates that there might be a limit to the effects conferred by this approach. 5-HT2A receptors were shown to form hetero-dimers with metabotropic glutamate 2 (mGlu2) receptors, in which 5-HT2A blockade and mGlu2 activation elicit equivalent effects at the downstream signalling level. We have previously shown that mGlu2 activation reduces both dyskinesia and psychosis-like behaviours (PLBs) induced by L-3,4-dihydroxyphenylalanine (l-DOPA), in the 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-lesioned primate. Here, we hypothesised that concurrent 5-HT2A antagonism and mGlu2 activation would provide greater anti-dyskinetic and anti-psychotic benefits than either approach alone. We conducted 3 series of experiments in the MPTP-lesioned marmoset. In the first series of experiments, the mGlu2 positive allosteric modulator LY-487,379 and the 5-HT2A antagonist EMD-281,014, either alone or in combination, were added to l-DOPA. In the second series of experiments, the mGlu2/3 orthosteric agonist LY-354,740 and EMD-281,014, either alone or in combination, were added to l-DOPA. In the last series of experiments, we investigated whether mGlu2 blockade would diminish the effects of antagonising 5-HT2A receptors. To this end, the mGlu2/3 orthosteric antagonist LY-341,495 and EMD-281,014, either alone or in combination, were added to l-DOPA. We found that the anti-dyskinetic effect of the combination LY-487,379/EMD-281,014 was greater than the ones conferred by LY-487,379 (by 35%, P < 0.05) and EMD-281,014 (by 38%, P < 0.01). The anti-dyskinetic and anti-psychotic effects of the combination LY-354,740/EMD-281,014 were also greater than the ones conferred by LY-354,740 (by 57% for dyskinesia and 54% for PLBs, both P < 0.001) and EMD-281,014 (by 61% for dyskinesia and 53% for PLBs, both P < 0.001). The anti-parkinsonian action of l-DOPA was maintained with all treatments. Lastly, the addition of LY-341,495 abolished the therapeutic effects of EMD-281,014 on dyskinesia and PLBs. Our results suggest that mGlu2 activation may enhance the anti-dyskinetic and anti-psychotic effects of 5-HT2A blockade and could provide relief to PD patients with dyskinesia and psychotic symptoms beyond what can be achieved with current therapies.
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Affiliation(s)
- Cynthia Kwan
- Neurodegenerative Disease Group, Montreal Neurological Institute, Montreal, QC, Canada
| | - Imane Frouni
- Neurodegenerative Disease Group, Montreal Neurological Institute, Montreal, QC, Canada; Département de Pharmacologie et Physiologie, Université de Montréal, Montreal, QC, Canada
| | - Stephen G Nuara
- Comparative Medicine & Animal Resource Centre, McGill University, Montreal, QC, Canada
| | - Sébastien Belliveau
- Neurodegenerative Disease Group, Montreal Neurological Institute, Montreal, QC, Canada
| | - Woojin Kang
- Neurodegenerative Disease Group, Montreal Neurological Institute, Montreal, QC, Canada
| | - Adjia Hamadjida
- Neurodegenerative Disease Group, Montreal Neurological Institute, Montreal, QC, Canada
| | - Dominique Bédard
- Neurodegenerative Disease Group, Montreal Neurological Institute, Montreal, QC, Canada
| | - Francis Beaudry
- Groupe de Recherche en Pharmacologie Animale Du Québec, Département de Biomédecine Vétérinaire, Faculté de Médecine Vétérinaire, Université de Montréal, Saint-Hyacinthe, QC, Canada
| | - Michel Panisset
- Unité des Troubles Du Mouvement André-Barbeau, Service de Neurologie, Département de Médecine, Centre Hospitalier de L'Université de Montréal, Montreal, QC, Canada; Département de Neurosciences, Université de Montréal, Montreal, QC, Canada
| | - Jim C Gourdon
- Comparative Medicine & Animal Resource Centre, McGill University, Montreal, QC, Canada
| | - Philippe Huot
- Neurodegenerative Disease Group, Montreal Neurological Institute, Montreal, QC, Canada; Département de Pharmacologie et Physiologie, Université de Montréal, Montreal, QC, Canada; Department of Neurology and Neurosurgery, McGill University, Montreal, QC, Canada; Movement Disorder Clinic, Division of Neurology, Department of Neuroscience, McGill University Health Centre, Montreal, QC, Canada.
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22
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Cortical influences of serotonin and glutamate on layer V pyramidal neurons. PROGRESS IN BRAIN RESEARCH 2021; 261:341-378. [PMID: 33785135 DOI: 10.1016/bs.pbr.2020.11.002] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Layer V pyramidal neurons constitute principle output neurons of the medial prefrontal cortex (mPFC)/neocortex to subcortical regions including the intralaminar/midline thalamic nuclei, amygdala, basal ganglia, brainstem nuclei and the spinal cord. The effects of 5-hydroxytryptamine (5-HT) on layer V pyramidal cells primarily reflect a range of excitatory influences through 5-HT2A receptors and inhibitory influences through non-5-HT2A receptors, including 5-HT1A receptors. While the 5-HT2A receptor is primarily a postsynaptic receptor on throughout the apical dendritic field of 5-HT2A receptors, activation of a minority of 5-HT2A receptors also appears to increase spontaneous excitatory postsynaptic currents/potentials (EPSCs/EPSPs) via a presynaptic effect on thalamocortical terminals arising from the midline and intralaminar thalamic nuclei. Activation of 5-HT2A receptors by the phenethylamine hallucinogen also appears to increase asynchronous release of glutamate upon the layer V pyramidal dendritic field, an effect that is suppressed by 5-HT itself through non-5-HT2A receptors. Serotonergic hallucinogens acting on 5-HT2A receptors also appears to increase gene expression of immediate early genes (iEG) and other receptors appearing to induce an iEG-like response like BDNF. Psychedelic hallucinogens acting on 5-HT2A receptors also induce head twitches in rodents that appear related to induction of glutamate release. These electrophysiological, biochemical and behavioral effects of serotonergic hallucinogens appear to be related to modulating glutamatergic thalamocortical neurotransmission and/or shifting the balance toward 5-HT2A receptor activation and away from non-5-HT2A receptor activation. These 5-HT2A receptor induced responses are modulated by feedback homeostatic mechanisms through mGlu2, mGlu4, and mGlu8 presynaptic receptors on thalamocortical terminals. These 5-HT2A receptor and glutamatergic interactions also appear to play a role on higher cortical functions of the mPFC such as motoric impulsivity and antidepressant-like behavioral responses on the differential-reinforcement-of low rate 72-s (DRL 72-s schedule). These mutually opposing effects between 5-HT2A receptor and mGlu autoreceptor activation (e.g., blocking 5-HT2A receptors and enhancing activity at mGlu2 receptors) may play a clinical role with respect to currently prescribed or novel antidepressant drugs. Thus, there is an important balance between 5-HT2A receptor activation and activation of mGlu autoreceptors on prefrontal cortical layer V pyramidal cells with respect to the electrophysiological, biochemical and behavioral effects serotonergic hallucinogenic drugs.
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23
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Frouni I, Kwan C, Nuara SG, Belliveau S, Kang W, Hamadjida A, Bédard D, Gourdon JC, Huot P. Effect of the mGlu 2 positive allosteric modulator CBiPES on dyskinesia, psychosis-like behaviours and parkinsonism in the MPTP-lesioned marmoset. J Neural Transm (Vienna) 2021; 128:73-81. [PMID: 33392826 DOI: 10.1007/s00702-020-02287-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2020] [Accepted: 12/08/2020] [Indexed: 11/24/2022]
Abstract
Advanced Parkinson's disease (PD) is often complicated by the occurrence of dyskinesia, motor fluctuations and psychosis. To this day, few treatment options are available for each of these phenomena, and they are at times not effective or elicit adverse events, leaving some patients short of therapeutic options. We have recently shown that positive allosteric modulation of metabotropic 2 (mGlu2) receptors with the prototypical positive allosteric modulator (PAM) LY-487,379 is efficacious at alleviating both dyskinesia and psychosis-like behaviours (PLBs), while simultaneously enhancing the anti-parkinsonian action of L-3,4-dihydroxyphenylalanine (L-DOPA), in the 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-lesioned marmoset. Here, we assessed the effects of CBiPES, a mGlu2 PAM derived from LY-487,379, but with improved pharmacokinetic properties. Six MPTP-lesioned marmosets with reproducible dyskinesia and PLBs were administered L-DOPA in combination with vehicle or CBiPES (0.1, 1 and 10 mg/kg), after which their behaviour was rated. CBiPES 10 mg/kg reduced global dyskinesia by 60% (P < 0.0001), while peak dose dyskinesia was reduced by 66% (P < 0.001), compared to L-DOPA/vehicle. CBiPES 10 mg/kg also diminished global PLBs by 56% (P < 0.0001), while peak dose PLBs were reduced by 64% (P < 0.001), compared to L-DOPA/vehicle. Lastly, CBiPES enhanced the anti-parkinsonian action of L-DOPA, by reducing global parkinsonian disability by 43% (P < 0.01), compared to L-DOPA/vehicle. Our results provide further evidence that mGlu2 positive allosteric modulation may be an approach that could be efficacious for the treatment of dyskinesia, psychosis and motor fluctuations in PD.
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Affiliation(s)
- Imane Frouni
- Neurodegenerative Disease Group, Montreal Neurological Institute, Montreal, QC, Canada.,Département de Pharmacologie et Physiologie, Université de Montréal, Montreal, QC, Canada
| | - Cynthia Kwan
- Neurodegenerative Disease Group, Montreal Neurological Institute, Montreal, QC, Canada
| | - Stephen G Nuara
- Comparative Medicine & Animal Resource Centre, McGill University, Montreal, QC, Canada
| | - Sébastien Belliveau
- Neurodegenerative Disease Group, Montreal Neurological Institute, Montreal, QC, Canada
| | - Woojin Kang
- Neurodegenerative Disease Group, Montreal Neurological Institute, Montreal, QC, Canada
| | - Adjia Hamadjida
- Neurodegenerative Disease Group, Montreal Neurological Institute, Montreal, QC, Canada
| | - Dominique Bédard
- Neurodegenerative Disease Group, Montreal Neurological Institute, Montreal, QC, Canada
| | - Jim C Gourdon
- Comparative Medicine & Animal Resource Centre, McGill University, Montreal, QC, Canada
| | - Philippe Huot
- Neurodegenerative Disease Group, Montreal Neurological Institute, Montreal, QC, Canada. .,Département de Pharmacologie et Physiologie, Université de Montréal, Montreal, QC, Canada. .,Department of Neurology and Neurosurgery, McGill University, Montreal, QC, Canada. .,Movement Disorder Clinic, Division of Neurology, Department of Neuroscience, McGill University Health Centre, Montreal, QC, Canada.
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24
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Pottie E, Dedecker P, Stove CP. Identification of psychedelic new psychoactive substances (NPS) showing biased agonism at the 5-HT2AR through simultaneous use of β-arrestin 2 and miniGαq bioassays. Biochem Pharmacol 2020; 182:114251. [DOI: 10.1016/j.bcp.2020.114251] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2020] [Revised: 09/25/2020] [Accepted: 09/25/2020] [Indexed: 11/29/2022]
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25
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Ellaithy A, Gonzalez-Maeso J, Logothetis DA, Levitz J. Structural and Biophysical Mechanisms of Class C G Protein-Coupled Receptor Function. Trends Biochem Sci 2020; 45:1049-1064. [PMID: 32861513 PMCID: PMC7642020 DOI: 10.1016/j.tibs.2020.07.008] [Citation(s) in RCA: 50] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2020] [Revised: 07/22/2020] [Accepted: 07/30/2020] [Indexed: 02/07/2023]
Abstract
Groundbreaking structural and spectroscopic studies of class A G protein-coupled receptors (GPCRs), such as rhodopsin and the β2 adrenergic receptor, have provided a picture of how structural rearrangements between transmembrane helices control ligand binding, receptor activation, and effector coupling. However, the activation mechanism of other GPCR classes remains more elusive, in large part due to complexity in their domain assembly and quaternary structure. In this review, we focus on the class C GPCRs, which include metabotropic glutamate receptors (mGluRs) and gamma-aminobutyric acid B (GABAB) receptors (GABABRs) most prominently. We discuss the unique biophysical questions raised by the presence of large extracellular ligand-binding domains (LBDs) and constitutive homo/heterodimerization. Furthermore, we discuss how recent studies have begun to unravel how these fundamental class C GPCR features impact the processes of ligand binding, receptor activation, signal transduction, regulation by accessory proteins, and crosstalk with other GPCRs.
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Affiliation(s)
- Amr Ellaithy
- Department of Neurology, University of Iowa, Iowa City, IA 52242, USA; Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA; Department of Neurology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Javier Gonzalez-Maeso
- Department of Physiology and Biophysics, Virginia Commonwealth University School of Medicine, Richmond, VA 23298, USA
| | - Diomedes A Logothetis
- Department of Pharmaceutical Sciences, School of Pharmacy, Bouvé College of Health Sciences, Northeastern University, Boston, MA 02115, USA; Department of Chemistry and Chemical Biology, College of Science and Center for Drug Discovery, Northeastern University, Boston, MA 02115, USA
| | - Joshua Levitz
- Department of Biochemistry, Weill Cornell Medicine, New York, NY 10065, USA.
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26
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Toneatti R, Shin JM, Shah UH, Mayer CR, Saunders JM, Fribourg M, Arsenovic PT, Janssen WG, Sealfon SC, López-Giménez JF, Benson DL, Conway DE, González-Maeso J. Interclass GPCR heteromerization affects localization and trafficking. Sci Signal 2020; 13:eaaw3122. [PMID: 33082287 PMCID: PMC7717648 DOI: 10.1126/scisignal.aaw3122] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Membrane trafficking processes regulate G protein-coupled receptor (GPCR) activity. Although class A GPCRs are capable of activating G proteins in a monomeric form, they can also potentially assemble into functional GPCR heteromers. Here, we showed that the class A serotonin 5-HT2A receptors (5-HT2ARs) affected the localization and trafficking of class C metabotropic glutamate receptor 2 (mGluR2) through a mechanism that required their assembly as heteromers in mammalian cells. In the absence of agonists, 5-HT2AR was primarily localized within intracellular compartments, and coexpression of 5-HT2AR with mGluR2 increased the intracellular distribution of the otherwise plasma membrane-localized mGluR2. Agonists for either 5-HT2AR or mGluR2 differentially affected trafficking through Rab5-positive endosomes in cells expressing each component of the 5-HT2AR-mGluR2 heterocomplex alone, or together. In addition, overnight pharmacological 5-HT2AR blockade with clozapine, but not with M100907, decreased mGluR2 density through a mechanism that involved heteromerization between 5-HT2AR and mGluR2. Using TAT-tagged peptides and chimeric constructs that are unable to form the interclass 5-HT2AR-mGluR2 complex, we demonstrated that heteromerization was necessary for the 5-HT2AR-dependent effects on mGluR2 subcellular distribution. The expression of 5-HT2AR also augmented intracellular localization of mGluR2 in mouse frontal cortex pyramidal neurons. Together, our data suggest that GPCR heteromerization may itself represent a mechanism of receptor trafficking and sorting.
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MESH Headings
- Amino Acids/pharmacology
- Animals
- Bridged Bicyclo Compounds, Heterocyclic/pharmacology
- Cell Membrane/metabolism
- Clozapine/pharmacology
- Endosomes/metabolism
- HEK293 Cells
- Humans
- Mice, 129 Strain
- Mice, Knockout
- Microscopy, Confocal
- Multiprotein Complexes/chemistry
- Multiprotein Complexes/metabolism
- Protein Multimerization
- Protein Transport/drug effects
- Receptor, Serotonin, 5-HT2A/chemistry
- Receptor, Serotonin, 5-HT2A/genetics
- Receptor, Serotonin, 5-HT2A/metabolism
- Receptors, Metabotropic Glutamate/chemistry
- Receptors, Metabotropic Glutamate/genetics
- Receptors, Metabotropic Glutamate/metabolism
- Serotonin Antagonists/pharmacology
- Signal Transduction
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Affiliation(s)
- Rudy Toneatti
- Department of Physiology and Biophysics, School of Medicine, Virginia Commonwealth University, Richmond, VA 23298, USA
| | - Jong M Shin
- Department of Physiology and Biophysics, School of Medicine, Virginia Commonwealth University, Richmond, VA 23298, USA
| | - Urjita H Shah
- Department of Physiology and Biophysics, School of Medicine, Virginia Commonwealth University, Richmond, VA 23298, USA
| | - Carl R Mayer
- Department of Biomedical Engineering, College of Engineering, Virginia Commonwealth University, Richmond, VA 23220, USA
| | - Justin M Saunders
- Department of Physiology and Biophysics, School of Medicine, Virginia Commonwealth University, Richmond, VA 23298, USA
| | - Miguel Fribourg
- Department of Neurology, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
- Translational Transplant Research Center, Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Paul T Arsenovic
- Department of Biomedical Engineering, College of Engineering, Virginia Commonwealth University, Richmond, VA 23220, USA
| | - William G Janssen
- Department Neuroscience, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Stuart C Sealfon
- Department of Neurology, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Juan F López-Giménez
- Department of Physiology and Biophysics, School of Medicine, Virginia Commonwealth University, Richmond, VA 23298, USA
- Instituto de Parasitología y Biomedicina "López-Neyra", CSIC, E-18016 Granada, Spain
| | - Deanna L Benson
- Department Neuroscience, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Daniel E Conway
- Department of Biomedical Engineering, College of Engineering, Virginia Commonwealth University, Richmond, VA 23220, USA
| | - Javier González-Maeso
- Department of Physiology and Biophysics, School of Medicine, Virginia Commonwealth University, Richmond, VA 23298, USA.
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Poulie CBM, Liu N, Jensen AA, Bunch L. Design, Synthesis, and Pharmacological Characterization of Heterobivalent Ligands for the Putative 5-HT 2A/mGlu 2 Receptor Complex. J Med Chem 2020; 63:9928-9949. [PMID: 32815361 DOI: 10.1021/acs.jmedchem.0c01058] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
We report the synthesis of the first series of heterobivalent ligands targeting the putative heteromeric 5-HT2A/mGlu2 receptor complex, based on the 5-HT2A antagonist MDL-100,907 and the mGlu2 ago-PAM JNJ-42491293. The functional properties of monovalent and heterobivalent ligands were characterized in 5-HT2A-, mGlu2/Gqo5-, 5-HT2A/mGlu2-, and 5-HT2A/mGlu2/Gqo5-expressing HEK293 cells using a Ca2+ imaging assay and a [3H]ketanserin binding assay. Pronounced functional crosstalk was observed between the two receptors in 5-HT2A/mGlu2 and 5-HT2A/mGlu2/Gqo5 cells. While the synthesized monovalent ligands retained the 5-HT2A antagonist and mGlu2 ago-PAM functionalities, the seven bivalent ligands inhibited 5-HT-induced responses in 5-HT2A/mGlu2 cells and both 5-HT- and Glu-induced responses in 5-HT2A/mGlu2/Gqo5 cells. However, no definitive correlation between the functional potency and spacer length of the ligands was observed, an observation substantiated by the binding affinities exhibited by the compounds in 5-HT2A, 5-HT2A/mGlu2, and 5-HT2A/mGlu2/Gqo5 cells. In conclusion, while functional crosstalk between 5-HT2A and mGlu2 was demonstrated, it remains unclear how these heterobivalent ligands interact with the putative receptor complex.
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Affiliation(s)
- Christian B M Poulie
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, 2100 Copenhagen OE, Denmark
| | - Na Liu
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, 2100 Copenhagen OE, Denmark
| | - Anders A Jensen
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, 2100 Copenhagen OE, Denmark
| | - Lennart Bunch
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, 2100 Copenhagen OE, Denmark
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28
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Cisani F, Roggeri A, Olivero G, Garrone B, Tongiani S, Di Giorgio FP, Pittaluga A. Acute Low Dose of Trazodone Recovers Glutamate Release Efficiency and mGlu2/3 Autoreceptor Impairments in the Spinal Cord of Rats Suffering From Chronic Sciatic Ligation. Front Pharmacol 2020; 11:1108. [PMID: 32765286 PMCID: PMC7379891 DOI: 10.3389/fphar.2020.01108] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2020] [Accepted: 07/08/2020] [Indexed: 11/16/2022] Open
Abstract
We investigated whether chronic sciatic ligation modifies the glutamate release in spinal cord nerve endings (synaptosomes) as well as the expression and the function of presynaptic release-regulating mGlu2/3 autoreceptors and 5-HT2A heteroreceptors in these particles. Synaptosomes were from the spinal cord of animals suffering from the sciatic ligation that developed on day 6 post-surgery a significant decrease of the force inducing paw-withdrawal in the lesioned paw. The exocytosis of glutamate (quantified as release of preloaded [3H]D-aspartate, [3H]D-Asp) elicited by a mild depolarizing stimulus (15 mM KCl) was significantly increased in synaptosomes from injured rats when compared to controls (uninjured rats). The mGlu2/3 agonist LY379268 (1000 pM) significantly inhibited the 15 mM KCl-evoked [3H]D-Asp overflow from control synaptosomes, but not in terminals isolated from injured animals. Differently, a low concentration (10 nM) of (±) DOI, unable to modify the 15 mM KCl-evoked [3H]D-Asp overflow in control spinal cord synaptosomes, significantly reduced the glutamate exocytosis in nerve endings isolated from the injured rats. Acute oral trazodone (TZD, 0.3 mg/kg on day 7 post-surgery) efficiently recovered glutamate exocytosis as well as the efficiency of LY379268 in inhibiting this event in spinal cord synaptosomes from injured animals. The sciatic ligation significantly reduced the expression of mGlu2/3, but not of 5-HT2A, receptor proteins in spinal cord synaptosomal lysates. Acute TZD recovered this parameter. Our results support the use of 5-HT2A antagonists for restoring altered spinal cord glutamate plasticity in rats suffering from sciatic ligation.
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Affiliation(s)
- Francesca Cisani
- Department of Pharmacy, DIFAR, Pharmacology and Toxicology Section and Center of Excellence for Biomedical Research, University of Genoa, Genoa, Italy
| | - Alessandra Roggeri
- Department of Pharmacy, DIFAR, Pharmacology and Toxicology Section and Center of Excellence for Biomedical Research, University of Genoa, Genoa, Italy
| | - Guendalina Olivero
- Department of Pharmacy, DIFAR, Pharmacology and Toxicology Section and Center of Excellence for Biomedical Research, University of Genoa, Genoa, Italy
| | - Beatrice Garrone
- Angelini RR&D (Research, Regulatory & Development), Angelini Pharma S.p.A., Rome, Italy
| | - Serena Tongiani
- Angelini RR&D (Research, Regulatory & Development), Angelini Pharma S.p.A., Rome, Italy
| | | | - Anna Pittaluga
- Department of Pharmacy, DIFAR, Pharmacology and Toxicology Section and Center of Excellence for Biomedical Research, University of Genoa, Genoa, Italy.,IRCCS Ospedale Policlinico San Martino, Genova, Italy
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29
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Marek GJ, Salek AA. Extending the Specificity of DRL 72-s Behavior for Screening Antidepressant-Like Effects of Glutamatergic Clinically Validated Anxiolytic or Antidepressant Drugs in Rats. J Pharmacol Exp Ther 2020; 374:200-210. [PMID: 32265323 DOI: 10.1124/jpet.119.264069] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2019] [Accepted: 03/13/2020] [Indexed: 12/26/2022] Open
Abstract
Both an agonist and its associated prodrug for metabotropic glutamate2/3 (mGlu2/3) receptors demonstrated anxiolytic efficacy in large, randomized, multicenter, double-blind, placebo-controlled trials studying patients with generalized anxiety disorder (GAD). These mGlu2/3 receptor agonists produced robust preclinical anxiolytic-like effects in rodent models. Several different metabotropic glutamate2 receptor positive allosteric modulators have been found to produce antidepressant-like effects on several preclinical screening paradigms, including differential-reinforcement-of-low-rate 72-second (DRL 72-s) behavior [increased reinforcers, decreased response rate, and cohesive rightward shifts in inter-response time distributions]. Although mGlu2/3 receptor agonists have not been tested formally for therapeutic effects in treating patients with major depressive disorder, these compounds generally fail to exert antidepressant-like effects in preclinical screening paradigms and did not improve depressive symptoms in GAD trials. Thus, the present studies were designed to test the potential antidepressant-like effects of the mGlu2/3 receptor agonist 1S,2S,5R,6S-2-aminobicyclo[3.1.0]hexane-2,6-bicarboxylate monohydrate (LY354740) on the DRL 72-s schedule. LY354740 did not test similarly to clinically validated antidepressant drugs when administered alone or when coadministered with the selective serotonin reuptake inhibitor fluoxetine in rats. Another glutamate-based antidepressant drug, the uncompetitive N-methyl-D-aspartate channel blocker racemic ketamine, exerted antidepressant-like effects when administered at subanesthetic doses in rats. The findings further support the specificity of rat DRL 72-s behavior when screening for anxiolytic versus antidepressant drugs and extend testing of compounds with glutamatergic mechanisms of action. SIGNIFICANCE STATEMENT: The metabotropic glutamate2/3 receptor agonist and clinically validated anxiolytic drug 1S,2S,5R,6S-2-aminobicyclo[3.1.0]hexane-2,6-bicarboxylate monohydrate did not test similar to antidepressant drugs (increased reinforcers, decreased response rate, and cohesive rightward shifts in the inter-response time distribution) when tested on differential-reinforcement-of-low-rate 72-second (DRL 72-s) behavior and also did not enhance the antidepressant-like effects of the serotonin reuptake inhibitor fluoxetine. The uncompetitive N-methyl-D-aspartate receptor antagonist ketamine increased the reinforcement rate, decreased the response rate, and induced a rightward shift in the inter-response time distribution similar to antidepressant drugs; these results confirm the utility of DRL 72-s schedule of reinforcement when testing clinically validated anxiolytic versus antidepressant glutamatergic drugs.
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Affiliation(s)
- Gerard J Marek
- Yale School of Medicine Department of Psychiatry, Ribicoff Research Facilities of the Connecticut Mental Health Center, New Haven, Connecticut
| | - Allyson A Salek
- Yale School of Medicine Department of Psychiatry, Ribicoff Research Facilities of the Connecticut Mental Health Center, New Haven, Connecticut
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30
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Nuara SG, Hamadjida A, Kwan C, Bédard D, Frouni I, Gourdon JC, Huot P. Combined mGlu2 orthosteric stimulation and positive allosteric modulation alleviates l-DOPA-induced psychosis-like behaviours and dyskinesia in the parkinsonian marmoset. J Neural Transm (Vienna) 2020; 127:1023-1029. [DOI: 10.1007/s00702-020-02185-z] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2020] [Accepted: 03/27/2020] [Indexed: 02/07/2023]
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31
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Lipone P, Ehler E, Nastaj M, Palka-Kisielowska I, Cruccu G, Truini A, Di Loreto G, Del Vecchio A, Pochiero I, Comandini A, Calisti F, Cattaneo A. Efficacy and Safety of Low Doses of Trazodone in Patients Affected by Painful Diabetic Neuropathy and Treated with Gabapentin: A Randomized Controlled Pilot Study. CNS Drugs 2020; 34:1177-1189. [PMID: 32936427 PMCID: PMC7658082 DOI: 10.1007/s40263-020-00760-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
BACKGROUND Painful diabetic neuropathy is an important therapeutic challenge as the efficacy of analgesic drugs in this setting is still unsatisfactory. Monotherapy with available treatments is often not sufficient and a combination of drugs is necessary. Trazodone (TRZ) is a compound with a multi-modal mechanism of action, being a serotonin-2 antagonist/reuptake inhibitor developed and approved for the treatment of depression in several countries. Previous clinical trials suggest a possible beneficial effect of low doses of trazodone for the treatment of patients affected by painful diabetic neuropathy. OBJECTIVE This phase II study was designed to collect data on the efficacy and safety of low doses of TRZ combined with gabapentin after 8 weeks of treatment in patients affected by painful diabetic neuropathy. METHODS This was a randomized, double-blind, placebo-controlled, multi-center, international, prospective study. Male and female diabetic patients aged 18-75 years and affected by painful diabetic neuropathy were eligible for enrollment. Subjects were randomized (1:1:1 ratio) to TRZ30 (10 mg three times daily for 8 weeks) or TRZ60 (20 mg three times daily for 8 weeks) or placebo. Gabapentin as background therapy was administered in open-label conditions to all patients. The primary endpoint was the change from baseline of the Brief Pain Inventory Short Form item 5 to week 8. Secondary endpoints included the other Brief Pain Inventory Short Form items, and the assessment of anxiety, sleep, quality of life, patient's improvement, and safety. RESULTS One hundred and forty-one patients were included in the intention-to-treat population: 43 allocated to the TRZ30 group, 50 to the TRZ60 group, and 48 to the placebo group. After 8 weeks, the mean changes of Brief Pain Inventory Short Form item 5 from baseline were - 3.1, - 2.6, and - 2.5 in the TRZ30, TRZ60, and placebo groups, respectively. No statistically significant differences between groups were seen. Nevertheless, a better trend was observed for TRZ30 vs placebo (95% confidence interval - 1.30, 0.15; p = 0.1179), on top of the background effect of gabapentin administered to all study groups. 62.8% of patients achieved a ≥ 50% reduction in the TRZ30 group, 54% in the TRZ60 group, and 45.8% in the placebo group. At the same time, a statistically significant improvement was observed in Brief Pain Inventory Short Form item 6 for TRZ30 vs placebo (95% confidence interval - 1.54, - 0.07; p = 0.0314). No serious adverse event occurred during the trial and the most frequent treatment-emergent adverse events involved nervous system, QT prolongation, and gastrointestinal disorders. CONCLUSIONS All treatment groups showed a clinically meaningful pain improvement; nevertheless, patients in the TRZ30 treatment group reported better efficacy outcomes. This finding suggests that low doses of TRZ could be useful for treating painful diabetic neuropathy, and support further adequately powered confirmatory trials investigating the efficacy of TRZ. CLINICAL TRIAL REGISTRATION NCT03202979, date of registration: 29/06/2017.
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Affiliation(s)
- Paola Lipone
- Angelini Pharma S.p.A., Viale Amelia 70, Rome, Italy
| | - Edvard Ehler
- Neurological Unit, Regional Hospital Pardubice, Pardubice, Czech Republic
| | | | | | - Giorgio Cruccu
- Department of Human Neuroscience, Sapienza University of Rome, Rome, Italy.
| | - Andrea Truini
- Department of Human Neuroscience, Sapienza University of Rome, Rome, Italy
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5-HT 2A receptor-dependent phosphorylation of mGlu 2 receptor at Serine 843 promotes mGlu 2 receptor-operated G i/o signaling. Mol Psychiatry 2019; 24:1610-1626. [PMID: 29858599 DOI: 10.1038/s41380-018-0069-6] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/31/2017] [Revised: 02/19/2018] [Accepted: 03/13/2018] [Indexed: 12/31/2022]
Abstract
The serotonin 5-HT2A and glutamate mGlu2 receptors continue to attract particular attention, given their implication in psychosis associated with schizophrenia and the mechanism of action of atypical antipsychotics and a new class of antipsychotics, respectively. A large body of evidence indicates a functional crosstalk between both receptors in the brain, but the underlying mechanisms are not entirely elucidated. Here, we have explored the influence of 5-HT2A receptor upon the phosphorylation pattern of mGlu2 receptor in light of the importance of specific phosphorylation events in regulating G protein-coupled receptor signaling and physiological outcomes. Among the five mGlu2 receptor-phosphorylated residues identified in HEK-293 cells, the phosphorylation of Ser843 was enhanced upon mGlu2 receptor stimulation by the orthosteric agonist LY379268 only in cells co-expressing the 5-HT2A receptor. Likewise, administration of LY379268 increased mGlu2 receptor phosphorylation at Ser843 in prefrontal cortex of wild-type mice but not 5-HT2A-/- mice. Exposure of HEK-293 cells co-expressing mGlu2 and 5-HT2A receptors to 5-HT also increased Ser843 phosphorylation state to a magnitude similar to that measured in LY379268-treated cells. In both HEK-293 cells and prefrontal cortex, Ser843 phosphorylation elicited by 5-HT2A receptor stimulation was prevented by the mGlu2 receptor antagonist LY341495, while the LY379268-induced effect was abolished by the 5-HT2A receptor antagonist M100907. Mutation of Ser843 into alanine strongly reduced Gi/o signaling elicited by mGlu2 or 5-HT2A receptor stimulation in cells co-expressing both receptors. Collectively, these findings identify mGlu2 receptor phosphorylation at Ser843 as a key molecular event that underlies the functional crosstalk between both receptors.
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Activation of mGlu2/3 receptors, a novel therapeutic approach to alleviate dyskinesia and psychosis in experimental parkinsonism. Neuropharmacology 2019; 158:107725. [DOI: 10.1016/j.neuropharm.2019.107725] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2019] [Revised: 06/27/2019] [Accepted: 07/24/2019] [Indexed: 12/11/2022]
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34
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Borroto-Escuela DO, Fuxe K. Oligomeric Receptor Complexes and Their Allosteric Receptor-Receptor Interactions in the Plasma Membrane Represent a New Biological Principle for Integration of Signals in the CNS. Front Mol Neurosci 2019; 12:230. [PMID: 31607863 PMCID: PMC6773811 DOI: 10.3389/fnmol.2019.00230] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2018] [Accepted: 09/09/2019] [Indexed: 12/14/2022] Open
Abstract
G protein-coupled receptors (GPCRs) not only exist as monomers but also as homomers and heteromers in which allosteric receptor-receptor interactions take place, modulating the functions of the participating GPCR protomers. GPCRs can also form heteroreceptor complexes with ionotropic receptors and receptor tyrosine kinases modulating their function. Furthermore, adaptor proteins interact with receptor protomers and modulate their interactions. The state of the art is that the allosteric receptor-receptor interactions are reciprocal, highly dynamic and substantially alter the signaling, trafficking, recognition and pharmacology of the participating protomers. The pattern of changes appears to be unique for each heteromer and can favor antagonistic or facilitatory interactions or switch the G protein coupling from e.g., Gi/o to Gq or to beta-arrestin signaling. It lends a new dimension to molecular integration in the nervous system. Future direction should be aimed at determining the receptor interface involving building models of selected heterodimers. This will make design of interface-interfering peptides that specifically disrupt the heterodimer possible. This will help to determine the functional role of the allosteric receptor-receptor interactions as well as the integration of signals at the plasma membrane by the heteroreceptor complexes, vs. integration of the intracellular signaling pathways. Integration of signals also at the plasma membrane seems crucial in view of the hypothesis that learning and memory at a molecular level takes place by reorganization of homo and heteroreceptor complexes in the postsynaptic membrane. Homo and heteroreceptor complexes are in balance with each other, and their disbalance is linked to disease. Targeting heteroreceptor complexes represents a novel strategy for the treatment of brain disorders.
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Affiliation(s)
- Dasiel O. Borroto-Escuela
- Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden
- Department of Biomolecular Science, Section of Physiology, University of Urbino, Campus Scientifico Enrico Mattei, Urbino, Italy
- Grupo Bohío-Estudio, Observatorio Cubano de Neurociencias, Yaguajay, Cuba
| | - Kjell Fuxe
- Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden
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Shah UH, González-Maeso J. Serotonin and Glutamate Interactions in Preclinical Schizophrenia Models. ACS Chem Neurosci 2019; 10:3068-3077. [PMID: 30807107 DOI: 10.1021/acschemneuro.9b00044] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
The serotonergic and glutamatergic neurotransmitter systems have both been implicated in the pathophysiology of schizophrenia, and there are multiple lines of evidence to demonstrate that they can interact in a functionally relevant manner. Particularly, it has been demonstrated that serotonin (5-hydroxytryptamine) 2A (5-HT2A) receptors and metabotropic glutamate type 2 (mGlu2) receptors can assemble into a functional heteromeric complex and modulate each other's function. This heteromeric complex has been implicated in the mechanism of action of hallucinogens as well as antipsychotic agents, and its role has been demonstrated in both in vitro and in vivo systems. Additionally, the difference in the changes in Gi/o and Gq/11 protein activity when a ligand binds to the heteromeric complex can be used as an index to predict the pro- or antipsychotic properties of an agent. Signaling via the heteromer is dysregulated in postmortem human brain samples of schizophrenia subjects, which may be linked to altered cortical functions. Alternative routes for the functional crosstalk between mGlu2 and 5-HT2A receptors include synaptic and epigenetic mechanisms. This Review highlights the advances made over the past few years in elucidating the structural and functional mechanisms underlying crosstalk between 5-HT2A and mGlu2 receptors in preclinical models of schizophrenia.
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Affiliation(s)
- Urjita H. Shah
- Department of Physiology and Biophysics, Virginia Commonwealth University School of Medicine, Richmond, Virginia 23298, United States
| | - Javier González-Maeso
- Department of Physiology and Biophysics, Virginia Commonwealth University School of Medicine, Richmond, Virginia 23298, United States
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Canal CE. Serotonergic Psychedelics: Experimental Approaches for Assessing Mechanisms of Action. Handb Exp Pharmacol 2019; 252:227-260. [PMID: 29532180 PMCID: PMC6136989 DOI: 10.1007/164_2018_107] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Recent, well-controlled - albeit small-scale - clinical trials show that serotonergic psychedelics, including psilocybin and lysergic acid diethylamide, possess great promise for treating psychiatric disorders, including treatment-resistant depression. Additionally, fresh results from a deluge of clinical neuroimaging studies are unveiling the dynamic effects of serotonergic psychedelics on functional activity within, and connectivity across, discrete neural systems. These observations have led to testable hypotheses regarding neural processing mechanisms that contribute to psychedelic effects and therapeutic benefits. Despite these advances and a plethora of preclinical and clinical observations supporting a central role for brain serotonin 5-HT2A receptors in producing serotonergic psychedelic effects, lingering and new questions about mechanisms abound. These chiefly pertain to molecular neuropharmacology. This chapter is devoted to illuminating and discussing such questions in the context of preclinical experimental approaches for studying mechanisms of action of serotonergic psychedelics, classic and new.
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Affiliation(s)
- Clinton E Canal
- Department of Pharmaceutical Sciences, College of Pharmacy, Mercer University, Atlanta, GA, USA.
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Chronic treatment with a metabotropic mGlu2/3 receptor agonist diminishes behavioral response to a phenethylamine hallucinogen. Psychopharmacology (Berl) 2019; 236:821-830. [PMID: 30448990 PMCID: PMC6778591 DOI: 10.1007/s00213-018-5118-y] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/27/2018] [Accepted: 11/08/2018] [Indexed: 01/15/2023]
Abstract
BACKGROUND There is evidence that mGlu2/3 receptors regulate 5-HT2A signaling, interactions that have been theorized to play a role in the antipsychotic-like effects of mGlu2/3 agonists as well as the hallucinogenic effects of 5-HT2A agonists. One approach to unraveling this interaction is through the chronic administration of agonists at the two receptors, which should influence the functional properties of the targeted receptor due to receptor downregulation or desensitization and thereby alter crosstalk between the two receptors. In this study, we investigated whether chronic treatment with the mGlu2/3 agonist LY379268 would alter the behavioral response to a phenethylamine hallucinogen, 25CN-NBOH, which acts as a selective 5-HT2A agonist. METHODS We first conducted a dose response of 25CN-NBOH (0.1, 0.3, 1, 3, or 10 mg/kg) to confirm the effects on head-twitch response (HTR) and then blockade studies with either the M100907 (0.1 mg/kg) or SB242084 (0.1, 0.3, or 1 mg/kg) to determine the contribution of 5-HT2A and 5-HT2C to 25CN-NBOH-induced HTR, respectively. To determine whether an mGlu2/3 agonist could block 25CN-NBOH-induced HTR, mice were pretreated with vehicle or LY379268 (0.1, 1, or 10 mg/kg) prior to 25CN-NBOH, and HTR was assessed. The effects of chronic LY379268 on 5-HT2A agonist-induced HTR were evaluated by treating mice with either vehicle or LY379268 (10 mg/kg) for 21 days and measuring 25CN-NBOH-induced HTR 48 h after the final LY379268 treatment. The following day (72 h after the final LY379268 treatment), the ability of acute LY379268 to block PCP-induced locomotor activity was assessed. RESULTS 25CN-NBOH dose-dependently increased the HTR, a 5-HT2A-mediated behavior, in mice. The selective 5-HT2A antagonist M100907 completely blocked the HTR induced by 25CN-NBOH, whereas the selective 5-HT2C antagonist SB242084 had no effect on the HTR. Administration of LY379268 (10 mg/kg SC) attenuated the HTR induced by 1 mg/kg 25CN-NBOH by ~ 50%. Chronic treatment (21 days) with LY379268 also attenuated the HTR response to 25CN-NBOH when tested 48 h after the last dose of LY379268. In locomotor tests, acute LY379268 significantly attenuated PCP-induced locomotor activity in the chronic vehicle treatment group; by contrast, there was only a trend for an overall interaction in the chronic LY379268 group, with LY379268 blocking the locomotor-stimulating effects of PCP only during the last 20 min. CONCLUSIONS These data are consistent with a functional interaction between mGlu2/3 and 5-HT2A receptors, although the specific mechanism for the interaction is not known. These data support the hypothesis that mGlu2/3 receptors play a prominent role in modulating the behavioral response to 5-HT2A receptor activation.
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Zamberlan F, Sanz C, Martínez Vivot R, Pallavicini C, Erowid F, Erowid E, Tagliazucchi E. The Varieties of the Psychedelic Experience: A Preliminary Study of the Association Between the Reported Subjective Effects and the Binding Affinity Profiles of Substituted Phenethylamines and Tryptamines. Front Integr Neurosci 2018; 12:54. [PMID: 30467466 PMCID: PMC6235949 DOI: 10.3389/fnint.2018.00054] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2018] [Accepted: 10/15/2018] [Indexed: 02/05/2023] Open
Abstract
Classic psychedelics are substances of paramount cultural and neuroscientific importance. A distinctive feature of psychedelic drugs is the wide range of potential subjective effects they can elicit, known to be deeply influenced by the internal state of the user ("set") and the surroundings ("setting"). The observation of cross-tolerance and a series of empirical studies in humans and animal models support agonism at the serotonin (5-HT)2A receptor as a common mechanism for the action of psychedelics. The diversity of subjective effects elicited by different compounds has been attributed to the variables of "set" and "setting," to the binding affinities for other 5-HT receptor subtypes, and to the heterogeneity of transduction pathways initiated by conformational receptor states as they interact with different ligands ("functional selectivity"). Here we investigate the complementary (i.e., not mutually exclusive) possibility that such variety is also related to the binding affinity for a range of neurotransmitters and monoamine transporters including (but not limited to) 5-HT receptors. Building on two independent binding affinity datasets (compared to "in silico" estimates) in combination with natural language processing tools applied to a large repository of reports of psychedelic experiences (Erowid's Experience Vaults), we obtained preliminary evidence supporting that the similarity between the binding affinity profiles of psychoactive substituted phenethylamines and tryptamines is correlated with the semantic similarity of the associated reports. We also showed that the highest correlation was achieved by considering the combined binding affinity for the 5-HT, dopamine (DA), glutamate, muscarinic and opioid receptors and for the Ca+ channel. Applying dimensionality reduction techniques to the reports, we linked the compounds, receptors, transporters and the Ca+ channel to distinct fingerprints of the reported subjective effects. To the extent that the existing binding affinity data is based on a low number of displacement curves that requires further replication, our analysis produced preliminary evidence consistent with the involvement of different binding sites in the reported subjective effects elicited by psychedelics. Beyond the study of this particular class of drugs, we provide a methodological framework to explore the relationship between the binding affinity profiles and the reported subjective effects of other psychoactive compounds.
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Affiliation(s)
- Federico Zamberlan
- Departamento de Física, Universidad de Buenos Aires, Buenos Aires, Argentina
- Instituto de Física de Buenos Aires (IFIBA) and National Scientific and Technical Research Council (CONICET), Buenos Aires, Argentina
| | - Camila Sanz
- Departamento de Física, Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Rocío Martínez Vivot
- Instituto de Física de Buenos Aires (IFIBA) and National Scientific and Technical Research Council (CONICET), Buenos Aires, Argentina
- Instituto de Investigaciones Biomédicas (BIOMED) and Technical Research Council (CONICET), Buenos Aires, Argentina
| | - Carla Pallavicini
- Instituto de Física de Buenos Aires (IFIBA) and National Scientific and Technical Research Council (CONICET), Buenos Aires, Argentina
- Fundación Para la Lucha contra las Enfermedades Neurológicas de la Infancia (FLENI), Buenos Aires, Argentina
| | - Fire Erowid
- Erowid Center, Grass Valley, CA, United States
| | | | - Enzo Tagliazucchi
- Departamento de Física, Universidad de Buenos Aires, Buenos Aires, Argentina
- Instituto de Física de Buenos Aires (IFIBA) and National Scientific and Technical Research Council (CONICET), Buenos Aires, Argentina
- UMR7225 Institut du Cerveau et de la Moelle épinière (ICM), Paris, France
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Marek GJ. Interactions of Hallucinogens with the Glutamatergic System: Permissive Network Effects Mediated Through Cortical Layer V Pyramidal Neurons. Curr Top Behav Neurosci 2018; 36:107-135. [PMID: 28831734 DOI: 10.1007/7854_2017_480] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Recordings made from layer V (L5) pyramidal cells of the prefrontal cortex (PFC) and neocortex in rodent slice preparations have shown that serotonin (5-hydroxytryptamine, 5-HT) and serotonergic hallucinogens induce an increase in the frequency of spontaneous excitatory postsynaptic currents (EPSCs) in the apical dendritic field by activating 5-HT2A receptors. Serotonergic hallucinogens induce late EPSCs and increase recurrent network activity when subcortical or mid-cortical regions are stimulated at low frequencies (e.g., 0.1 Hz). A range of agonists or positive allosteric modulators (PAMs) for mostly Gi/o-coupled receptors, including metabotropic glutamate2 (mGlu2), adenosine A1, or μ-opioid receptors, suppress these effects of 5-HT2A receptor stimulation. Furthermore, a range of mostly Gq/11-coupled receptors (including orexin2 [OX2]; α1-adrenergic, and mGlu5 receptors) similarly induce glutamate (Glu) release onto L5 pyramidal cells. Evidence implicates a number of brain regions in mediating these effects of serotonergic hallucinogens and Gq/11-coupled receptors including the midline and intralaminar thalamic nuclei, claustrum, and neurons in deep PFC. These effects on 5-HT2A receptors and related GPCRs appear to play a major role in the behavioral effects of serotonergic hallucinogens, such as head twitches in rodents and higher order behaviors such as rodent lever pressing on the differential-reinforcement-of-low rate 72-s (DRL 72-s) schedule. This implies that the effects of 5-HT2A receptor activation on the activity of L5 pyramidal cells may be responsible for mediating a range of behaviors linked to limbic circuitry with connectivity between the PFC, striatum, thalamus, claustrum, striatum, amygdala, and the hippocampal formation.
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Affiliation(s)
- Gerard J Marek
- Global Medical Science, CNS and Pain, Astellas Pharma Global Development, 1 Astellas Way, Northbrook, IL, 60062, USA.
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Abstract
Initially G protein-coupled receptors, GPCRs, were thought to act as monomers, but recently strong evidence has been gathered indicating that they are capable of forming homo- and heterodimers or higher order oligomeric complexes, and that the dimerization phenomenon can modulate the pharmacological response and function of these receptors. In this chapter we point to the great potential of alternative therapeutic approach targeted at GPCR dimers, which is especially important in the field of neuropsychopharmacology. We also included a brief description of methods used for studying the phenomenon of GPCR oligomerization, with particular attention paid to the proximity ligation assay, PLA, the procedure which allows the study of interactions between receptors not only in vitro but also in vivo, with good anatomical resolution, what is especially important in the studies of various GPCRs involved in central neurotransmission.
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Borroto-Escuela DO, Tarakanov AO, Brito I, Fuxe K. Glutamate heteroreceptor complexes in the brain. Pharmacol Rep 2018; 70:936-950. [PMID: 32002960 DOI: 10.1016/j.pharep.2018.04.002] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2018] [Revised: 03/26/2018] [Accepted: 04/09/2018] [Indexed: 10/17/2022]
Abstract
The existence of mGluR, NMDAR, AMPAR and putative KAR heteroreceptor complexes in synaptic and extrasynaptic regions of brain glutamate synapses represents a major integrative mechanism. Our aim in the current article is to analyze if the formation of the different types glutamate hetereceptor complexes involves the contribution of triplet amino acid homologies (protriplets) in a postulated receptor interface based on the triplet puzzle theory. Seven main sets (lists) of receptor pairs in databases were used containing various sets (lists) of human receptor heteromers and nonheteromers obtained from the available scientific publications including the publically available GPCR-hetnet database. Brain mGluR1-mGluR5 and mGluR2-mGluR4 isoreceptor complexes were demonstrated with a predominant extrasynaptic localization at a post- and prejunctional localization. The existence of putative mGluR4-mGluR7 heteroreceptor complexes in the basal ganglia is proposed. Metabotropic glutamate receptor subtypes also participated in the formation of a large number of heteroreceptor complexes like mGluR1-A1R, mGluR5-A2AR, mGluR5-D2R and D2R-A2AR-mGluR5, located in relation to glutamate synapses, especially in the basal ganglia. A putative mGluR1-GABAB1/2 heterocomplex may also exist. NMDAR heteroreceptor complexes were also demonstrated as a fundamental integrative mechanism in the glutamate synapse and its extrasynaptic membranes. It represented fundamental work on inter alia NMDAR-mGluR5, NMDAR-D1R and NMDAR-D2R heteroreceptor complexes involving both antagonistic and facilitatory allosteric receptor-receptor interactions. As to AMPA receptors, a heterocomplex was found for the interaction between IFNgR1 and the AMPAR mediated via the subunit GluA1 which may be of relevance for neuroinflammation. AMPAR-D2R heteroreceptor complexes were also demonstrated. Besides glutamate heteroreceptor complexes and their allosteric receptor-receptor interactions, a significant mechanism for the functional crosstalk can also be phosphorylation and/or reorganization of adapter proteins with dynamic binding to the two receptors modulating the allosteric receptor mechanism.
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Affiliation(s)
- Dasiel O Borroto-Escuela
- Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden.,Department of Biomolecular Science, Section of Physiology, University of Urbino, Campus Scientifico Enrico Mattei, Urbino, Italy.,Grupo Bohío-Estudio, Observatorio Cubano de Neurociencias, Yaguajay, Cuba
| | - Alexander O Tarakanov
- St. Petersburg Institute for Informatics and Automation, Russian Academy of Sciences, Saint Petersburg, Russia
| | - Ismel Brito
- Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden.,Grupo Bohío-Estudio, Observatorio Cubano de Neurociencias, Yaguajay, Cuba
| | - Kjell Fuxe
- Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden.
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Olivero G, Grilli M, Vergassola M, Bonfiglio T, Padolecchia C, Garrone B, Di Giorgio FP, Tongiani S, Usai C, Marchi M, Pittaluga A. 5-HT 2A-mGlu2/3 receptor complex in rat spinal cord glutamatergic nerve endings: A 5-HT 2A to mGlu2/3 signalling to amplify presynaptic mechanism of auto-control of glutamate exocytosis. Neuropharmacology 2018; 133:429-439. [PMID: 29499271 DOI: 10.1016/j.neuropharm.2018.02.030] [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: 12/07/2017] [Revised: 02/23/2018] [Accepted: 02/26/2018] [Indexed: 11/25/2022]
Abstract
Presynaptic mGlu2/3 autoreceptors exist in rat spinal cord nerve terminals as suggested by the finding that LY379268 inhibited the 15 mM KCl-evoked release of [3H]D-aspartate ([3H]D-Asp) in a LY341495-sensitive manner. Spinal cord glutamatergic nerve terminals also possess presynaptic release-regulating 5-HT2A heteroreceptors. Actually, the 15 mM KCl-evoked [3H]D-Asp exocytosis from spinal cord synaptosomes was reduced by the 5-HT2A agonist (±)DOI, an effect reversed by the 5-HT2A antagonists MDL11,939, MDL100907, ketanserin and trazodone (TZD). We investigated whether mGlu2/3 and 5-HT2A receptors colocalize and cross-talk in these terminals and if 5-HT2A ligands modulate the mGlu2/3-mediated control of glutamate exocytosis. Western blot analysis and confocal microscopy highlighted the presence of mGlu2/3 and 5-HT2A receptor proteins in spinal cord VGLUT1 positive synaptosomes, where mGlu2/3 and 5-HT2A receptor immunoreactivities largely colocalize. Furthermore, mGlu2/3 immunoprecipitates from spinal cord synaptosomes were also 5-HT2A immunopositive. Interestingly, the 100 pM LY379268-induced reduction of the 15 mM KCl-evoked [3H]D-Asp overflow as well as its inhibition by 100 nM (±)DOI became undetectable when the two agonists were concomitantly added. Conversely, 5-HT2A antagonists (MDL11,939, MDL100907, ketanserin and TZD) reinforced the release-regulating activity of mGlu2/3 autoreceptors. Increased expression of mGlu2/3 receptor proteins in synaptosomal plasmamembranes paralleled the gain of function of the mGlu2/3 autoreceptors elicited by 5-HT2A antagonists. Based on these results, we propose that in spinal cord glutamatergic terminals i) mGlu2/3 and 5-HT2A receptors colocalize and interact one each other in an antagonist-like manner, ii) 5-HT2A antagonists are indirect positive allosteric modulator of mGlu2/3 autoreceptors controlling glutamate exocytosis.
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Affiliation(s)
- Guendalina Olivero
- Department of Pharmacy, DiFAR, Pharmacology and Toxicology Section, Viale Cembrano 4, 16148, Genoa, Italy
| | - Massimo Grilli
- Department of Pharmacy, DiFAR, Pharmacology and Toxicology Section, Viale Cembrano 4, 16148, Genoa, Italy; Center of Excellence for Biomedical Research, University of Genoa, Viale Benedetto XV, 16132, Genoa, Italy
| | - Matteo Vergassola
- Department of Pharmacy, DiFAR, Pharmacology and Toxicology Section, Viale Cembrano 4, 16148, Genoa, Italy
| | - Tommaso Bonfiglio
- Department of Pharmacy, DiFAR, Pharmacology and Toxicology Section, Viale Cembrano 4, 16148, Genoa, Italy
| | - Cristina Padolecchia
- Department of Pharmacy, DiFAR, Pharmacology and Toxicology Section, Viale Cembrano 4, 16148, Genoa, Italy
| | - Beatrice Garrone
- Angelini RR&D (Research, Regulatory & Development) - Angelini S.p.A., Piazzale della Stazione Snc, 00071, S. Palomba-Pomezia (Rome), Italy
| | - Francesco Paolo Di Giorgio
- Angelini RR&D (Research, Regulatory & Development) - Angelini S.p.A., Piazzale della Stazione Snc, 00071, S. Palomba-Pomezia (Rome), Italy
| | - Serena Tongiani
- Angelini RR&D (Research, Regulatory & Development) - Angelini S.p.A., Piazzale della Stazione Snc, 00071, S. Palomba-Pomezia (Rome), Italy
| | - Cesare Usai
- Institute of Biophysics, National Research Council, Via De Marini 6, 16149, Genoa, Italy
| | - Mario Marchi
- Department of Pharmacy, DiFAR, Pharmacology and Toxicology Section, Viale Cembrano 4, 16148, Genoa, Italy; Center of Excellence for Biomedical Research, University of Genoa, Viale Benedetto XV, 16132, Genoa, Italy
| | - Anna Pittaluga
- Department of Pharmacy, DiFAR, Pharmacology and Toxicology Section, Viale Cembrano 4, 16148, Genoa, Italy; Center of Excellence for Biomedical Research, University of Genoa, Viale Benedetto XV, 16132, Genoa, Italy.
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Carbonaro TM, Johnson MW, Hurwitz E, Griffiths RR. Double-blind comparison of the two hallucinogens psilocybin and dextromethorphan: similarities and differences in subjective experiences. Psychopharmacology (Berl) 2018; 235:521-534. [PMID: 29116367 PMCID: PMC6645364 DOI: 10.1007/s00213-017-4769-4] [Citation(s) in RCA: 62] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/17/2017] [Accepted: 10/19/2017] [Indexed: 01/21/2023]
Abstract
RATIONALE Although psilocybin and dextromethorphan (DXM) are hallucinogens, they have different receptor mechanisms of action and have not been directly compared. OBJECTIVE This study compared subjective, behavioral, and physiological effects of psilocybin and dextromethorphan under conditions that minimized expectancy effects. METHODS Single, acute oral doses of psilocybin (10, 20, 30 mg/70 kg), DXM (400 mg/70 kg), and placebo were administered under double-blind conditions to 20 healthy participants with histories of hallucinogen use. Instructions to participants and staff minimized expectancy effects. Various subjective, behavioral, and physiological effects were assessed after drug administration. RESULTS High doses of both drugs produced similar increases in participant ratings of peak overall drug effect strength, with similar times to maximal effect and time-course. Psilocybin produced orderly dose-related increases on most participant-rated subjective measures previously shown sensitive to hallucinogens. DXM produced increases on most of these same measures. However, the high dose of psilocybin produced significantly greater and more diverse visual effects than DXM including greater movement and more frequent, brighter, distinctive, and complex (including textured and kaleidoscopic) images and visions. Compared to DXM, psilocybin also produced significantly greater mystical-type and psychologically insightful experiences and greater absorption in music. In contrast, DXM produced larger effects than psilocybin on measures of disembodiment, nausea/emesis, and light-headedness. Both drugs increased systolic blood pressure, heart rate, and pupil dilation and decreased psychomotor performance and balance. CONCLUSIONS Psilocybin and DXM produced similar profiles of subjective experiences, with psilocybin producing relatively greater visual, mystical-type, insightful, and musical experiences, and DXM producing greater disembodiment.
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Affiliation(s)
- Theresa M Carbonaro
- Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, 5510 Nathan Shock Drive, Baltimore, MD, 21224-6823, USA
| | - Matthew W Johnson
- Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, 5510 Nathan Shock Drive, Baltimore, MD, 21224-6823, USA
| | - Ethan Hurwitz
- Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, 5510 Nathan Shock Drive, Baltimore, MD, 21224-6823, USA
| | - Roland R Griffiths
- Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, 5510 Nathan Shock Drive, Baltimore, MD, 21224-6823, USA.
- Department of Neuroscience, Johns Hopkins University School of Medicine, 5510 Nathan Shock Drive, Baltimore, MD, 21224-6823, USA.
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Abstract
Because of the ethical and regulatory hurdles associated with human studies, much of what is known about the psychopharmacology of hallucinogens has been derived from animal models. However, developing reliable animal models has proven to be a challenging task due to the complexity and variability of hallucinogen effects in humans. This chapter focuses on three animal models that are frequently used to test the effects of hallucinogens on unconditioned behavior: head twitch response (HTR), prepulse inhibition of startle (PPI), and exploratory behavior. The HTR has demonstrated considerable utility in the neurochemical actions of hallucinogens. However, the latter two models have clearer conceptual bridges to human phenomenology. Consistent with the known mechanism of action of hallucinogens in humans, the behavioral effects of hallucinogens in rodents are mediated primarily by activation of 5-HT2A receptors. There is evidence, however, that other receptors may play secondary roles. The structure-activity relationships (SAR) of hallucinogens are reviewed in relation to each model, with a focus on the HTR in rats and mice.
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Affiliation(s)
- Adam L Halberstadt
- Department of Psychiatry, University of California San Diego, La Jolla, CA, 92093-0804, USA.
- Research Service, VA San Diego Healthcare System, San Diego, CA, USA.
| | - Mark A Geyer
- Department of Psychiatry, University of California San Diego, La Jolla, CA, 92093-0804, USA
- Research Service, VA San Diego Healthcare System, San Diego, CA, USA
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Differential effects of antipsychotic and propsychotic drugs on prepulse inhibition and locomotor activity in Roman high- (RHA) and low-avoidance (RLA) rats. Psychopharmacology (Berl) 2017; 234:957-975. [PMID: 28154892 PMCID: PMC5492384 DOI: 10.1007/s00213-017-4534-8] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/31/2016] [Accepted: 01/09/2017] [Indexed: 10/20/2022]
Abstract
RATIONALE Animal models with predictive and construct validity are necessary for developing novel and efficient therapeutics for psychiatric disorders. OBJECTIVES We have carried out a pharmacological characterization of the Roman high- (RHA-I) and low-avoidance (RLA-I) rat strains with different acutely administered propsychotic (DOI, MK-801) and antipsychotic drugs (haloperidol, clozapine), as well as apomorphine, on prepulse inhibition (PPI) of startle and locomotor activity (activity cages). RESULTS RHA-I rats display a consistent deficit of PPI compared with RLA-I rats. The typical antipsychotic haloperidol (dopamine D2 receptor antagonist) reversed the PPI deficit characteristic of RHA-I rats (in particular at 65 and 70 dB prepulse intensities) and reduced locomotion in both strains. The atypical antipsychotic clozapine (serotonin/dopamine receptor antagonist) did not affect PPI in either strain, but decreased locomotion in a dose-dependent manner in both rat strains. The mixed dopamine D1/D2 agonist, apomorphine, at the dose of 0.05 mg/kg, decreased PPI in RHA-I, but not RLA-I rats. The hallucinogen drug DOI (5-HT2A agonist; 0.1-1.0 mg/kg) disrupted PPI in RLA-I rats in a dose-dependent manner at the 70 dB prepulse intensity, while in RHA-I rats, only the 0.5 mg/kg dose impaired PPI at the 80 dB prepulse intensity. DOI slightly decreased locomotion in both strains. Finally, clozapine attenuated the PPI impairment induced by the NMDA receptor antagonist MK-801 only in RLA-I rats. CONCLUSIONS These results add experimental evidence to the view that RHA-I rats represent a model with predictive and construct validity of some dopamine and 5-HT2A receptor-related features of schizophrenia.
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Sedative effect of Clozapine is a function of 5-HT 2A and environmental novelty. Eur Neuropsychopharmacol 2017; 27:70-81. [PMID: 27955831 DOI: 10.1016/j.euroneuro.2016.10.007] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/26/2016] [Revised: 09/06/2016] [Accepted: 10/29/2016] [Indexed: 12/20/2022]
Abstract
Antipsychotic drugs are the mainstay in the treatment of schizophrenia and bipolar disorder. However, antipsychotics often exhibit sedation or activity suppression among many other side effects, and the factors that influence them remain poorly understood. We now show, using a 5-HT2A knockout (Htr2a-/-) mouse, that environmental circumstances can affect suppression of activity induced by the atypical antipsychotic- Clozapine. We observed that Htr2a-/- mice were more resistant to Clozapine-induced suppression of activity (CISA) and this behaviour was dependent on the environment being 'novel'. In their 'home' environment, at identical doses the mice exhibited CISA. Interestingly, the effect of genotype and environmental novelty on CISA could not be extended to the other antipsychotics that were tested, i.e. Haloperidol and Risperidone. Haloperidol-induced activity suppression was independent of context and genotype. Whereas context affected Risperidone-induced activity suppression only in the Htr2a+/+ mice. Furthermore, we observed that caffeine, a stimulant, elicited resistance to CISA similar to that seen in the 'novel' context. Our study establishes a previously unknown interaction between the environmental context, 5-HT2A and CISA and emphasises the role of non-pharmacological factors such as environment on the effects of the drug, which seem antipsychotic-specific. Our findings should advance the understanding of the side effects of individual antipsychotics and the role of environment to overcome side effects such as sedation.
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Abstract
Hallucinogens comprise a diverse collection of chemicals with multifarious receptor actions in the central nervous system. Preclinical drug screening methods have proven invaluable in the evaluation and characterization of hallucinogen psychopharmacology. Used in concert with structural chemistry and receptor pharmacology methods, preclinical drug discrimination research has informed our current understanding of hallucinogens and the neurochemical receptor mechanisms responsible for their interoceptive stimulus effects. This chapter summarizes the strengths and limitations of drug discrimination as an in vivo drug detection method and offers a brief review of historical and contemporary drug discrimination research with classical hallucinogens.
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Gaitonde SA, González-Maeso J. Contribution of heteromerization to G protein-coupled receptor function. Curr Opin Pharmacol 2016; 32:23-31. [PMID: 27835800 DOI: 10.1016/j.coph.2016.10.006] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2016] [Revised: 10/22/2016] [Accepted: 10/24/2016] [Indexed: 12/22/2022]
Abstract
G protein-coupled receptors (GPCRs) are a remarkably multifaceted family of transmembrane proteins that exert a variety of physiological effects. Although family A GPCRs are able to operate as monomers, there is increasing evidence that heteromerization represents a fundamental aspect of receptor function, trafficking and pharmacology. Most recently, it has been suggested that GPCR heteromers may play a crucial role as new molecular targets of heteromer-selective and bivalent ligands. The current review summarizes key recent developments in these topics.
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Affiliation(s)
- Supriya A Gaitonde
- Department of Physiology and Biophysics, Virginia Commonwealth University School of Medicine, Richmond, VA 23298, United States
| | - Javier González-Maeso
- Department of Physiology and Biophysics, Virginia Commonwealth University School of Medicine, Richmond, VA 23298, United States.
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Mechanism of Assembly and Cooperativity of Homomeric and Heteromeric Metabotropic Glutamate Receptors. Neuron 2016; 92:143-159. [PMID: 27641494 DOI: 10.1016/j.neuron.2016.08.036] [Citation(s) in RCA: 122] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2016] [Revised: 07/19/2016] [Accepted: 08/19/2016] [Indexed: 11/23/2022]
Abstract
G protein-coupled receptors (GPCRs) mediate cellular responses to a wide variety of extracellular stimuli. GPCR dimerization may expand signaling diversity and tune functionality, but little is known about the mechanisms of subunit assembly and interaction or the signaling properties of heteromers. Using single-molecule subunit counting on class C metabotropic glutamate receptors (mGluRs), we map dimerization determinants and define a heterodimerization profile. Intersubunit fluorescence resonance energy transfer measurements reveal that interactions between ligand-binding domains control the conformational rearrangements underlying receptor activation. Selective liganding with photoswitchable tethered agonists conjugated to one or both subunits of covalently linked mGluR2 homodimers reveals that receptor activation is highly cooperative. Strikingly, this cooperativity is asymmetric in mGluR2/mGluR3 heterodimers. Our results lead to a model of cooperative activation of mGluRs that provides a framework for understanding how class C GPCRs couple extracellular binding to dimer reorganization and G protein activation.
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Carbonaro TM, Gatch MB. Neuropharmacology of N,N-dimethyltryptamine. Brain Res Bull 2016; 126:74-88. [PMID: 27126737 PMCID: PMC5048497 DOI: 10.1016/j.brainresbull.2016.04.016] [Citation(s) in RCA: 112] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2016] [Revised: 04/21/2016] [Accepted: 04/22/2016] [Indexed: 12/20/2022]
Abstract
N,N-dimethyltryptamine (DMT) is an indole alkaloid widely found in plants and animals. It is best known for producing brief and intense psychedelic effects when ingested. Increasing evidence suggests that endogenous DMT plays important roles for a number of processes in the periphery and central nervous system, and may act as a neurotransmitter. This paper reviews the current literature of both the recreational use of DMT and its potential roles as an endogenous neurotransmitter. Pharmacokinetics, mechanisms of action in the periphery and central nervous system, clinical uses and adverse effects are also reviewed. DMT appears to have limited neurotoxicity and other adverse effects except for intense cardiovascular effects when administered intravenously in large doses. Because of its role in nervous system signaling, DMT may be a useful experimental tool in exploring how the brain works, and may also be a useful clinical tool for treatment of anxiety and psychosis.
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Affiliation(s)
- Theresa M Carbonaro
- Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, Baltimore, MD, United States
| | - Michael B Gatch
- Center for Neuroscience Discovery University of North Texas Health Science Center Fort Worth, TX, United States.
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