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Dopamine Dynamics and Neurobiology of Non-Response to Antipsychotics, Relevance for Treatment Resistant Schizophrenia: A Systematic Review and Critical Appraisal. Biomedicines 2023; 11:biomedicines11030895. [PMID: 36979877 PMCID: PMC10046109 DOI: 10.3390/biomedicines11030895] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2023] [Revised: 03/08/2023] [Accepted: 03/12/2023] [Indexed: 03/17/2023] Open
Abstract
Treatment resistant schizophrenia (TRS) is characterized by a lack of, or suboptimal response to, antipsychotic agents. The biological underpinnings of this clinical condition are still scarcely understood. Since all antipsychotics block dopamine D2 receptors (D2R), dopamine-related mechanisms should be considered the main candidates in the neurobiology of antipsychotic non-response, although other neurotransmitter systems play a role. The aims of this review are: (i) to recapitulate and critically appraise the relevant literature on dopamine-related mechanisms of TRS; (ii) to discuss the methodological limitations of the studies so far conducted and delineate a theoretical framework on dopamine mechanisms of TRS; and (iii) to highlight future perspectives of research and unmet needs. Dopamine-related neurobiological mechanisms of TRS may be multiple and putatively subdivided into three biological points: (1) D2R-related, including increased D2R levels; increased density of D2Rs in the high-affinity state; aberrant D2R dimer or heteromer formation; imbalance between D2R short and long variants; extrastriatal D2Rs; (2) presynaptic dopamine, including low or normal dopamine synthesis and/or release compared to responder patients; and (3) exaggerated postsynaptic D2R-mediated neurotransmission. Future points to be addressed are: (i) a more neurobiologically-oriented phenotypic categorization of TRS; (ii) implementation of neurobiological studies by directly comparing treatment resistant vs. treatment responder patients; (iii) development of a reliable animal model of non-response to antipsychotics.
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2
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A dopaminergic mechanism of antipsychotic drug efficacy, failure, and failure reversal: the role of the dopamine transporter. Mol Psychiatry 2020; 25:2101-2118. [PMID: 30038229 PMCID: PMC7473845 DOI: 10.1038/s41380-018-0114-5] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/23/2017] [Revised: 04/30/2018] [Accepted: 05/25/2018] [Indexed: 12/21/2022]
Abstract
Antipsychotic drugs are effective interventions in schizophrenia. However, the efficacy of these agents often decreases over time, which leads to treatment failure and symptom recurrence. We report that antipsychotic efficacy in rat models declines in concert with extracellular striatal dopamine levels rather than insufficient dopamine D2 receptor occupancy. Antipsychotic efficacy was associated with a suppression of dopamine transporter activity, which was reversed during failure. Antipsychotic failure coincided with reduced dopamine neuron firing, which was not observed during antipsychotic efficacy. Synaptic field responses in dopamine target areas declined during antipsychotic efficacy and showed potentiation during failure. Antipsychotics blocked synaptic vesicle release during efficacy but enhanced this release during failure. We found that the pharmacological inhibition of the dopamine transporter rescued antipsychotic drug treatment outcomes, supporting the hypothesis that the dopamine transporter is a main target of antipsychotic drugs and predicting that dopamine transporter blockers may be an adjunct treatment to reverse antipsychotic treatment failure.
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3
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Colom M, Vidal B, Zimmer L. Is There a Role for GPCR Agonist Radiotracers in PET Neuroimaging? Front Mol Neurosci 2019; 12:255. [PMID: 31680859 PMCID: PMC6813225 DOI: 10.3389/fnmol.2019.00255] [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: 07/25/2019] [Accepted: 10/02/2019] [Indexed: 12/30/2022] Open
Abstract
Positron emission tomography (PET) is a molecular imaging modality that enables in vivo exploration of metabolic processes and especially the pharmacology of neuroreceptors. G protein-coupled receptors (GPCRs) play an important role in numerous pathophysiologic disorders of the central nervous system. Thus, they are targets of choice in PET imaging to bring proof concept of change in density in pathological conditions or in pharmacological challenge. At present, most radiotracers are antagonist ligands. In vitro data suggest that properties differ between GPCR agonists and antagonists: antagonists bind to receptors with a single affinity, whereas agonists are characterized by two different affinities: high affinity for receptors that undergo functional coupling to G-proteins, and low affinity for those that are not coupled. In this context, agonist radiotracers may be useful tools to give functional images of GPCRs in the brain, with high sensitivity to neurotransmitter release. Here, we review all existing PET radiotracers used from animals to humans and their role for understanding the ligand-receptor paradigm of GPCR in comparison with corresponding antagonist radiotracers.
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Affiliation(s)
- Matthieu Colom
- Lyon Neuroscience Research Center, INSERM, CNRS, Université de Lyon, Lyon, France.,CERMEP, Hospices Civils de Lyon, Bron, France
| | - Benjamin Vidal
- Lyon Neuroscience Research Center, INSERM, CNRS, Université de Lyon, Lyon, France
| | - Luc Zimmer
- Lyon Neuroscience Research Center, INSERM, CNRS, Université de Lyon, Lyon, France.,CERMEP, Hospices Civils de Lyon, Bron, France.,Institut National des Sciences et Techniques Nucléaires, CEA Saclay, Gif-sur-Yvette, France
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4
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Dahoun T, Nour MM, Adams RA, Trossbach S, Lee SH, Patel H, Curtis C, Korth C, Howes OD. Disrupted-in-schizophrenia 1 functional polymorphisms and D 2 /D 3 receptor availability: A [ 11 C]-(+)-PHNO imaging study. GENES BRAIN AND BEHAVIOR 2019; 18:e12596. [PMID: 31264367 DOI: 10.1111/gbb.12596] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/06/2019] [Revised: 06/17/2019] [Accepted: 06/17/2019] [Indexed: 11/28/2022]
Abstract
The disrupted-in-schizophrenia 1 (DISC1) protein has been implicated in a range of biological mechanisms underlying chronic mental disorders such as schizophrenia. Schizophrenia is associated with abnormal striatal dopamine signalling, and all antipsychotic drugs block striatal dopamine 2/3 receptors (D2/3 Rs). Importantly, the DISC1 protein directly interacts and forms a protein complex with the dopamine D2 receptor (D2 R) that inhibits agonist-induced D2 R internalisation. Moreover, animal studies have found large striatal increases in the proportion of D2 R receptors in a high affinity state (D2 high R) in DISC1 rodent models. Here, we investigated the relationship between the three most common polymorphisms altering the amino-acid sequence of the DISC1 protein (Ser704Cys (rs821616), Leu607Phe (rs6675281) and Arg264Gln (rs3738401)) and striatal D2/3 R availability in 41 healthy human volunteers, using [11 C]-(+)-PHNO positron emission tomography. We found no association between DISC1 polymorphisms and D2/3 R availability in the striatum and D2 R availability in the caudate and putamen. Therefore, despite a direct interaction between DISC1 and the D2 R, none of its main functional polymorphisms impact striatal D2/3 R binding potential, suggesting DISC1 variants act through other mechanisms.
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Affiliation(s)
- Tarik Dahoun
- Psychiatric Imaging Group, Robert Steiner MRI Unit, MRC London Institute of Medical Sciences, Hammersmith Hospital, London, UK.,Institute of Clinical Sciences, Faculty of Medicine, Imperial College London, Hammersmith Hospital, London, UK.,Department of Psychiatry, University of Oxford, Warneford Hospital, Oxford, UK
| | - Matthew M Nour
- Psychiatric Imaging Group, Robert Steiner MRI Unit, MRC London Institute of Medical Sciences, Hammersmith Hospital, London, UK.,Institute of Clinical Sciences, Faculty of Medicine, Imperial College London, Hammersmith Hospital, London, UK.,Department of Psychosis Studies, Institute of Psychiatry, Psychology & Neuroscience (IoPPN), King's College London, London, UK.,Max Planck UCL Centre for Computational Psychiatry and Ageing Research, University College London, Russell Square House, London, UK.,Wellcome Centre for Human Neuroimaging (WCHN), University College London, London, UK
| | - Rick A Adams
- Psychiatric Imaging Group, Robert Steiner MRI Unit, MRC London Institute of Medical Sciences, Hammersmith Hospital, London, UK.,Institute of Clinical Sciences, Faculty of Medicine, Imperial College London, Hammersmith Hospital, London, UK.,Division of Psychiatry, University College London, London, UK.,Institute of Cognitive Neuroscience, University College London, London, UK
| | - Svenja Trossbach
- Department Neuropathology, Medical Faculty, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Sang H Lee
- Department of Biostatistics and Health Informatics, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK.,NIHR BioResource Centre Maudsley, NIHR Maudsley Biomedical Research Centre (BRC) at South London and Maudsley NHS Foundation Trust (SLaM) & Institute of Psychiatry, Psychology and Neuroscience (IoPPN), King's College London, London, UK.,Social Genetic & Developmental Psychiatry Centre, Institute of Psychiatry, Psychology and Neuroscience (IoPPN), King's College London, London, UK
| | - Hamel Patel
- Department of Biostatistics and Health Informatics, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK.,NIHR BioResource Centre Maudsley, NIHR Maudsley Biomedical Research Centre (BRC) at South London and Maudsley NHS Foundation Trust (SLaM) & Institute of Psychiatry, Psychology and Neuroscience (IoPPN), King's College London, London, UK.,Social Genetic & Developmental Psychiatry Centre, Institute of Psychiatry, Psychology and Neuroscience (IoPPN), King's College London, London, UK
| | - Charles Curtis
- Institute of Clinical Sciences, Faculty of Medicine, Imperial College London, Hammersmith Hospital, London, UK.,Department of Biostatistics and Health Informatics, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK.,NIHR BioResource Centre Maudsley, NIHR Maudsley Biomedical Research Centre (BRC) at South London and Maudsley NHS Foundation Trust (SLaM) & Institute of Psychiatry, Psychology and Neuroscience (IoPPN), King's College London, London, UK
| | - Carsten Korth
- Department Neuropathology, Medical Faculty, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Oliver D Howes
- Psychiatric Imaging Group, Robert Steiner MRI Unit, MRC London Institute of Medical Sciences, Hammersmith Hospital, London, UK.,Institute of Clinical Sciences, Faculty of Medicine, Imperial College London, Hammersmith Hospital, London, UK.,Department of Psychosis Studies, Institute of Psychiatry, Psychology & Neuroscience (IoPPN), King's College London, London, UK
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5
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Caravaggio F, Iwata Y, Kim J, Shah P, Gerretsen P, Remington G, Graff-Guerrero A. What proportion of striatal D2 receptors are occupied by endogenous dopamine at baseline? A meta-analysis with implications for understanding antipsychotic occupancy. Neuropharmacology 2019; 163:107591. [PMID: 30940535 DOI: 10.1016/j.neuropharm.2019.03.034] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2019] [Revised: 03/25/2019] [Accepted: 03/27/2019] [Indexed: 11/30/2022]
Abstract
Using molecular imaging techniques - positron emission tomography (PET) and single-photon emission computed tomography (SPECT) - in conjunction with an acute dopamine depletion challenge (alpha-methyl-para-tyrosine) it is possible to estimate endogenous dopamine levels occupying striatal dopamine D2 receptors (D2R) in humans in vivo. However, it is unclear what proportion of striatal D2R are occupied by endogenous dopamine under normal conditions. This is important since it has been suggested that in schizophrenia there may be a substantial proportion of striatal D2R which are occupied by endogenous dopamine and not accessible by therapeutic doses of antipsychotics. In order to clarify these issues, we conducted a meta-analysis of dopamine depletion studies using substituted benzamide radiotracers in healthy persons. This meta-analysis suggests that anywhere from 8 to 21% (weighted average 11%) of striatal D2R may be occupied by endogenous dopamine at baseline. Using these estimates, we propose an updated occupancy model and tentatively suggest that antipsychotics inhibit a smaller proportion of the total pool of striatal D2R in vivo than previously acknowledged. This article is part of the issue entitled 'Special Issue on Antipsychotics'.
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Affiliation(s)
- Fernando Caravaggio
- Research Imaging Centre, Centre for Addiction and Mental Health, 250 College Street, Toronto, Ontario, M5T 1R8, Canada; Department of Psychiatry, University of Toronto, 250 College Street, Toronto, Ontario, M5T 1R8, Canada.
| | - Yusuke Iwata
- Research Imaging Centre, Centre for Addiction and Mental Health, 250 College Street, Toronto, Ontario, M5T 1R8, Canada; Department of Psychiatry, University of Toronto, 250 College Street, Toronto, Ontario, M5T 1R8, Canada
| | - Julia Kim
- Research Imaging Centre, Centre for Addiction and Mental Health, 250 College Street, Toronto, Ontario, M5T 1R8, Canada; Institute of Medical Science, University of Toronto, 1 Kings College Circle, Toronto, Ontario, M5S 1A8, Canada
| | - Parita Shah
- Research Imaging Centre, Centre for Addiction and Mental Health, 250 College Street, Toronto, Ontario, M5T 1R8, Canada; Institute of Medical Science, University of Toronto, 1 Kings College Circle, Toronto, Ontario, M5S 1A8, Canada
| | - Philip Gerretsen
- Research Imaging Centre, Centre for Addiction and Mental Health, 250 College Street, Toronto, Ontario, M5T 1R8, Canada; Department of Psychiatry, University of Toronto, 250 College Street, Toronto, Ontario, M5T 1R8, Canada; Institute of Medical Science, University of Toronto, 1 Kings College Circle, Toronto, Ontario, M5S 1A8, Canada
| | - Gary Remington
- Research Imaging Centre, Centre for Addiction and Mental Health, 250 College Street, Toronto, Ontario, M5T 1R8, Canada; Department of Psychiatry, University of Toronto, 250 College Street, Toronto, Ontario, M5T 1R8, Canada; Institute of Medical Science, University of Toronto, 1 Kings College Circle, Toronto, Ontario, M5S 1A8, Canada
| | - Ariel Graff-Guerrero
- Research Imaging Centre, Centre for Addiction and Mental Health, 250 College Street, Toronto, Ontario, M5T 1R8, Canada; Department of Psychiatry, University of Toronto, 250 College Street, Toronto, Ontario, M5T 1R8, Canada; Institute of Medical Science, University of Toronto, 1 Kings College Circle, Toronto, Ontario, M5S 1A8, Canada
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6
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McCutcheon RA, Nour MM, Dahoun T, Jauhar S, Pepper F, Expert P, Veronese M, Adams RA, Turkheimer F, Mehta MA, Howes OD. Mesolimbic Dopamine Function Is Related to Salience Network Connectivity: An Integrative Positron Emission Tomography and Magnetic Resonance Study. Biol Psychiatry 2019; 85:368-378. [PMID: 30389131 PMCID: PMC6360933 DOI: 10.1016/j.biopsych.2018.09.010] [Citation(s) in RCA: 64] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/31/2018] [Revised: 09/10/2018] [Accepted: 09/14/2018] [Indexed: 02/05/2023]
Abstract
BACKGROUND A wide range of neuropsychiatric disorders, from schizophrenia to drug addiction, involve abnormalities in both the mesolimbic dopamine system and the cortical salience network. Both systems play a key role in the detection of behaviorally relevant environmental stimuli. Although anatomical overlap exists, the functional relationship between these systems remains unknown. Preclinical research has suggested that the firing of mesolimbic dopamine neurons may activate nodes of the salience network, but in vivo human research is required given the species-specific nature of this network. METHODS We employed positron emission tomography to measure both dopamine release capacity (using the D2/3 receptor ligand 11C-PHNO, n = 23) and dopamine synthesis capacity (using 18F-DOPA, n = 21) within the ventral striatum. Resting-state functional magnetic resonance imaging was also undertaken in the same individuals to investigate salience network functional connectivity. A graph theoretical approach was used to characterize the relationship between dopamine measures and network connectivity. RESULTS Dopamine synthesis capacity was associated with greater salience network connectivity, and this relationship was particularly apparent for brain regions that act as information-processing hubs. In contrast, dopamine release capacity was associated with weaker salience network connectivity. There was no relationship between dopamine measures and visual and sensorimotor networks, indicating specificity of the findings. CONCLUSIONS Our findings demonstrate a close relationship between the salience network and mesolimbic dopamine system, and they are relevant to neuropsychiatric illnesses in which aberrant functioning of both systems has been observed.
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Affiliation(s)
- Robert A McCutcheon
- Department of Psychosis Studies, Institute of Psychiatry, Psychology and Neuroscience, Kings College London, De Crespigny Park, London, United Kingdom; Psychiatric Imaging Group, MRC London Institute of Medical Sciences, Hammersmith Hospital, London, United Kingdom; Faculty of Medicine, Institute of Clinical Sciences, Imperial College London, London, United Kingdom.
| | - Matthew M Nour
- Department of Psychosis Studies, Institute of Psychiatry, Psychology and Neuroscience, Kings College London, De Crespigny Park, London, United Kingdom; Psychiatric Imaging Group, MRC London Institute of Medical Sciences, Hammersmith Hospital, London, United Kingdom; Faculty of Medicine, Institute of Clinical Sciences, Imperial College London, London, United Kingdom
| | - Tarik Dahoun
- Psychiatric Imaging Group, MRC London Institute of Medical Sciences, Hammersmith Hospital, London, United Kingdom; Faculty of Medicine, Institute of Clinical Sciences, Imperial College London, London, United Kingdom; Department of Psychiatry, University of Oxford, Warneford Hospital, Oxford, United Kingdom
| | - Sameer Jauhar
- Department of Psychosis Studies, Institute of Psychiatry, Psychology and Neuroscience, Kings College London, De Crespigny Park, London, United Kingdom; Psychiatric Imaging Group, MRC London Institute of Medical Sciences, Hammersmith Hospital, London, United Kingdom; Faculty of Medicine, Institute of Clinical Sciences, Imperial College London, London, United Kingdom
| | - Fiona Pepper
- Department of Psychosis Studies, Institute of Psychiatry, Psychology and Neuroscience, Kings College London, De Crespigny Park, London, United Kingdom; Department of Neuroimaging, Institute of Psychiatry, Psychology and Neuroscience, Kings College London, De Crespigny Park, London, United Kingdom
| | - Paul Expert
- Department of Mathematics, Imperial College London, London, United Kingdom; EPSRC Centre for Mathematics of Precision Healthcare, Imperial College London, London, United Kingdom
| | - Mattia Veronese
- Department of Neuroimaging, Institute of Psychiatry, Psychology and Neuroscience, Kings College London, De Crespigny Park, London, United Kingdom
| | - Rick A Adams
- Institute of Cognitive Neuroscience, University College London, London, United Kingdom; Division of Psychiatry, University College London, London, United Kingdom
| | - Federico Turkheimer
- Department of Neuroimaging, Institute of Psychiatry, Psychology and Neuroscience, Kings College London, De Crespigny Park, London, United Kingdom
| | - Mitul A Mehta
- Department of Neuroimaging, Institute of Psychiatry, Psychology and Neuroscience, Kings College London, De Crespigny Park, London, United Kingdom
| | - Oliver D Howes
- Department of Psychosis Studies, Institute of Psychiatry, Psychology and Neuroscience, Kings College London, De Crespigny Park, London, United Kingdom; Psychiatric Imaging Group, MRC London Institute of Medical Sciences, Hammersmith Hospital, London, United Kingdom; Faculty of Medicine, Institute of Clinical Sciences, Imperial College London, London, United Kingdom
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7
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Shalgunov V, van Waarde A, Booij J, Michel MC, Dierckx RAJO, Elsinga PH. Hunting for the high-affinity state of G-protein-coupled receptors with agonist tracers: Theoretical and practical considerations for positron emission tomography imaging. Med Res Rev 2018; 39:1014-1052. [PMID: 30450619 PMCID: PMC6587759 DOI: 10.1002/med.21552] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2018] [Revised: 10/02/2018] [Accepted: 10/19/2018] [Indexed: 12/15/2022]
Abstract
The concept of the high‐affinity state postulates that a certain subset of G‐protein‐coupled receptors is primarily responsible for receptor signaling in the living brain. Assessing the abundance of this subset is thus potentially highly relevant for studies concerning the responses of neurotransmission to pharmacological or physiological stimuli and the dysregulation of neurotransmission in neurological or psychiatric disorders. The high‐affinity state is preferentially recognized by agonists in vitro. For this reason, agonist tracers have been developed as tools for the noninvasive imaging of the high‐affinity state with positron emission tomography (PET). This review provides an overview of agonist tracers that have been developed for PET imaging of the brain, and the experimental paradigms that have been developed for the estimation of the relative abundance of receptors configured in the high‐affinity state. Agonist tracers appear to be more sensitive to endogenous neurotransmitter challenge than antagonists, as was originally expected. However, other expectations regarding agonist tracers have not been fulfilled. Potential reasons for difficulties in detecting the high‐affinity state in vivo are discussed.
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Affiliation(s)
- Vladimir Shalgunov
- Department of Nuclear Medicine and Molecular Imaging, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - Aren van Waarde
- Department of Nuclear Medicine and Molecular Imaging, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - Jan Booij
- Department of Radiology and Nuclear Medicine, Amsterdam University Medical Centers, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Martin C Michel
- Department of Pharmacology, Johannes Gutenberg University, Mainz, Germany
| | - Rudi A J O Dierckx
- Department of Nuclear Medicine and Molecular Imaging, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands.,Department of Nuclear Medicine, Ghent University, University Hospital, Ghent, Belgium
| | - Philip H Elsinga
- Department of Nuclear Medicine and Molecular Imaging, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
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8
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Subburaju S, Sromek AW, Seeman P, Neumeyer JL. New Dopamine D2 Receptor Agonist, [ 3H]MCL-536, for Detecting Dopamine D2high Receptors in Vivo. ACS Chem Neurosci 2018; 9:1283-1289. [PMID: 29641175 DOI: 10.1021/acschemneuro.8b00096] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Increases in the D2 receptor high affinity state are associated with certain neurological disorders. We synthesized and characterized the high-affinity D2high ligand [3H]MCL-536 in competition binding against the D2/3 agonist R-(-)- N- n-propylnorapomorphine (NPA) and the D2/3 antagonist raclopride. The total binding of [3H]MCL-536 (minus that in the presence of 100 nM NPA) was measured by saturation binding in CHO cells expressing human D2long; the data yielded separable, nonsaturable nonspecific, and saturable specific components. The former represents an aporphine site common to NPA and [3H]MCL-536. The latter indicated specific binding to the total D2 receptors (both high and low-affinity states). [3H]MCL-536 had a Kd of 0.8 nM. In competition binding, NPA had a Ki of 0.16 nM, and raclopride had a Ki of 0.9 nM. Co-incubation with guanylylimidodiphosphate abolished binding to D2high. This unique profile makes radiolabeled MCL-536 a versatile tool for diagnostics and therapeutics, and may quantify D2high sites in schizophrenia and PD patients in vivo.
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Affiliation(s)
- Sivan Subburaju
- Division of Basic Neuroscience, Medicinal Chemistry Laboratory, McLean Hospital, Belmont, Massachusetts 02478, United States
- Department of Psychiatry, Harvard Medical School, Boston, Massachusetts 02115, United States
| | - Anna W. Sromek
- Division of Basic Neuroscience, Medicinal Chemistry Laboratory, McLean Hospital, Belmont, Massachusetts 02478, United States
- Department of Psychiatry, Harvard Medical School, Boston, Massachusetts 02115, United States
| | - Philip Seeman
- Departments of Pharmacology and Psychiatry, University of Toronto, 260 Heath St. West, unit 605, Toronto, Ontario Canada M5P 3L6
| | - John L. Neumeyer
- Division of Basic Neuroscience, Medicinal Chemistry Laboratory, McLean Hospital, Belmont, Massachusetts 02478, United States
- Department of Psychiatry, Harvard Medical School, Boston, Massachusetts 02115, United States
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9
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Chouinard G, Samaha AN, Chouinard VA, Peretti CS, Kanahara N, Takase M, Iyo M. Antipsychotic-Induced Dopamine Supersensitivity Psychosis: Pharmacology, Criteria, and Therapy. PSYCHOTHERAPY AND PSYCHOSOMATICS 2018. [PMID: 28647739 DOI: 10.1159/000477313] [Citation(s) in RCA: 155] [Impact Index Per Article: 25.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The first-line treatment for psychotic disorders remains antipsychotic drugs with receptor antagonist properties at D2-like dopamine receptors. However, long-term administration of antipsychotics can upregulate D2 receptors and produce receptor supersensitivity manifested by behavioral supersensitivity to dopamine stimulation in animals, and movement disorders and supersensitivity psychosis (SP) in patients. Antipsychotic-induced SP was first described as the emergence of psychotic symptoms with tardive dyskinesia (TD) and a fall in prolactin levels following drug discontinuation. In the era of first-generation antipsychotics, 4 clinical features characterized drug-induced SP: rapid relapse after drug discontinuation/dose reduction/switch of antipsychotics, tolerance to previously observed therapeutic effects, co-occurring TD, and psychotic exacerbation by life stressors. We review 3 recent studies on the prevalence rates of SP, and the link to treatment resistance and psychotic relapse in the era of second-generation antipsychotics (risperidone, paliperidone, perospirone, and long-acting injectable risperidone, olanzapine, quetiapine, and aripiprazole). These studies show that the prevalence rates of SP remain high in schizophrenia (30%) and higher (70%) in treatment-resistant schizophrenia. We then present neurobehavioral findings on antipsychotic-induced supersensitivity to dopamine from animal studies. Next, we propose criteria for SP, which describe psychotic symptoms and co-occurring movement disorders more precisely. Detection of mild/borderline drug-induced movement disorders permits early recognition of overblockade of D2 receptors, responsible for SP and TD. Finally, we describe 3 antipsychotic withdrawal syndromes, similar to those seen with other CNS drugs, and we propose approaches to treat, potentially prevent, or temporarily manage SP.
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Affiliation(s)
- Guy Chouinard
- Clinical Pharmacology and Toxicology Program, McGill University Montreal, Montreal, QC, Canada
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10
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Mach RH. Small Molecule Receptor Ligands for PET Studies of the Central Nervous System-Focus on G Protein Coupled Receptors. Semin Nucl Med 2017; 47:524-535. [PMID: 28826524 DOI: 10.1053/j.semnuclmed.2017.05.002] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
G protein-coupled receptors (GPRCs) are a class of proteins that are expressed in high abundance and are responsible for numerous signal transduction pathways in the central nervous system. Consequently, alterations in GPRC function have been associated with a wide variety of neurologic and neuropsychiatric disorders. The development of PET probes for imaging GPRCs has served as a major emphasis of PET radiotracer development and PET imaging studies over the past 30 years. In this review, a basic description of the biology of G proteins and GPRCs is provided. This includes recent evidence of the existence of dimeric and multimeric species of GPRCs that have been termed "receptor mosaics," with an emphasis on the different GPRCs that form complexes with the dopamine D2 receptor. An overview of the different PET radiotracers for imaging the component GPRC within these different multimeric complexes of the D2 receptor is also provided.
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Affiliation(s)
- Robert H Mach
- Department of Radiology, Perelman School Medicine, University of Pennsylvania, Philadelphia, PA.
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11
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Chang A, Fox SH. Psychosis in Parkinson's Disease: Epidemiology, Pathophysiology, and Management. Drugs 2017; 76:1093-118. [PMID: 27312429 DOI: 10.1007/s40265-016-0600-5] [Citation(s) in RCA: 72] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Psychotic symptoms are common in Parkinson's disease (PD) and are associated with poorer quality of life and increased caregiver burden. PD psychosis is correlated with several factors, such as more advanced disease, cognitive impairment, depression, and sleep disorders. The underlying causes of psychosis in PD thus involve a complex interplay between exogenous (e.g., drugs, intercurrent illnesses) and endogenous (e.g., PD disease pathology) factors. Current theories of the pathophysiology of PD psychosis have come from several neuropathological and neuroimaging studies that implicate pathways involving visual processing and executive function, including temporo-limbic structures and neocortical gray matter with altered neurotransmitter functioning (e.g., dopamine, serotonin, and acetylcholine). Treatment of PD psychosis requires a step-wise process, including initial careful investigation of treatable triggering conditions and a comprehensive evaluation with adjustment of PD medications and/or initiation of specific antipsychotic therapies. Clozapine remains the only recommended drug for the treatment of PD psychosis; however, because of regular blood monitoring, quetiapine is usually first-line therapy, although less efficacious. Emerging studies have focused on agents involving other neurotransmitters, including the serotonin 5-HT2A receptor inverse agonist pimavanserin, cholinesterase inhibitors, and antidepressants and anxiolytics.
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Affiliation(s)
- Anna Chang
- Morton and Gloria Shulman Movement Disorder Clinic, University of Toronto, Toronto Western Hospital, 7th Floor, McLaughlin Pavilion, 399 Bathurst Street, Toronto, ON, M5T 2S8, Canada.,Department of Neurology, Shin Kong Wu Ho-Su Memorial Hospital, Taipei, Taiwan
| | - Susan H Fox
- Morton and Gloria Shulman Movement Disorder Clinic, University of Toronto, Toronto Western Hospital, 7th Floor, McLaughlin Pavilion, 399 Bathurst Street, Toronto, ON, M5T 2S8, Canada.
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12
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Heightened Dopaminergic Response to Amphetamine at the D 3 Dopamine Receptor in Methamphetamine Users. Neuropsychopharmacology 2016; 41:2994-3002. [PMID: 27353309 PMCID: PMC5101546 DOI: 10.1038/npp.2016.108] [Citation(s) in RCA: 61] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/18/2015] [Revised: 05/16/2016] [Accepted: 06/22/2016] [Indexed: 02/05/2023]
Abstract
Neuroimaging studies in stimulant use (eg, cocaine, methamphetamine) disorders show that diminished dopamine release by dopamine-elevating drugs is a potential marker of relapse and suggest that increasing dopamine at the D2/3 receptors may be therapeutically beneficial. In contrast, recent investigations indicate heightened D3 receptor levels in stimulant users prompting the view that D3 antagonism may help prevent relapse. Here we tested whether a 'blunted' response to amphetamine in methamphetamine (MA) users extends to D3-rich brain areas. Fourteen MA users and 15 healthy controls completed two positron emission tomographic scans with a D3-preferring probe [11C]-(+)-PHNO at baseline and after amphetamine (0.4 mg/kg). Relative to healthy controls, MA users had greater decreases in [11C]-(+)-PHNO binding (increased dopamine release) after amphetamine in D3-rich substantia nigra (36 vs 20%, p=0.03) and globus pallidus (30 vs 17%, p=0.06), which correlated with self-reported 'drug wanting'. We did not observe a 'blunted' dopamine response to amphetamine in D2-rich striatum; however, drug use severity was negatively associated with amphetamine-induced striatal changes in [11C]-(+)-PHNO binding. Our study provides evidence that dopamine transmission in extrastriatal 'D3-areas' is not blunted but rather increased in MA users. Together with our previous finding of elevated D3 receptor level in MA users, the current observation suggests that greater dopaminergic transmission at the D3 dopamine receptor may contribute to motivation to use drugs and argues in favor of D3 antagonism as a possible therapeutic tool to reduce craving and relapse in MA addiction.
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13
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Gaiser EC, Gallezot JD, Worhunsky PD, Jastreboff AM, Pittman B, Kantrovitz L, Angarita GA, Cosgrove KP, Potenza MN, Malison RT, Carson RE, Matuskey D. Elevated Dopamine D 2/3 Receptor Availability in Obese Individuals: A PET Imaging Study with [ 11C](+)PHNO. Neuropsychopharmacology 2016; 41:3042-3050. [PMID: 27374277 PMCID: PMC5101552 DOI: 10.1038/npp.2016.115] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/28/2016] [Revised: 05/27/2016] [Accepted: 06/27/2016] [Indexed: 01/09/2023]
Abstract
Most prior work with positron emission tomography (PET) dopamine subtype 2/3 receptor (D2/3R) non-selective antagonist tracers suggests that obese (OB) individuals exhibit lower D2/3Rs when compared with normal weight (NW) individuals. A D3-preferring D2/3R agonist tracer, [11C](+)PHNO, has demonstrated that body mass index (BMI) was positively associated with D2/3R availability within striatal reward regions. To date, OB individuals have not been studied with [11C](+)PHNO. We assessed D2/3R availability in striatal and extrastriatal reward regions in 14 OB and 14 age- and gender-matched NW individuals with [11C](+)PHNO PET utilizing a high-resolution research tomograph. Additionally, in regions where group D2/3R differences were observed, secondary analyses of 42 individuals that constituted an overweight cohort was done to study the linear association between BMI and D2/3R availability in those respective regions. A group-by-brain region interaction effect (F7, 182=2.08, p=0.047) was observed. Post hoc analyses revealed that OB individuals exhibited higher tracer binding in D3-rich regions: the substantia nigra/ventral tegmental area (SN/VTA) (+20%; p=0.02), ventral striatum (VST) (+14%; p<0.01), and pallidum (+11%; p=0.02). BMI was also positively associated with D2/3R availability in the SN/VTA (r=0.34, p=0.03), VST (r=0.36, p=0.02), and pallidum (r=0.30, p=0.05) across all subjects. These data suggest that individuals who are obese have higher D2/3R availability in brain reward regions densely populated with D3Rs, potentially identifying a novel pharmacologic target for the treatment of obesity.
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Affiliation(s)
- Edward C Gaiser
- Department of Radiology and Biomedical Imaging, Yale University, New Haven, CT, USA,Department of Psychiatry, Yale University, New Haven, CT, USA
| | | | - Patrick D Worhunsky
- Department of Radiology and Biomedical Imaging, Yale University, New Haven, CT, USA,Department of Psychiatry, Yale University, New Haven, CT, USA
| | - Ania M Jastreboff
- Department of Internal Medicine, Endocrinology, Yale University, New Haven, CT, USA,Department of Pediatrics, Pediatric Endocrinology, Yale University, New Haven, CT, USA
| | - Brian Pittman
- Department of Psychiatry, Yale University, New Haven, CT, USA
| | | | | | - Kelly P Cosgrove
- Department of Radiology and Biomedical Imaging, Yale University, New Haven, CT, USA,Department of Psychiatry, Yale University, New Haven, CT, USA
| | - Marc N Potenza
- Department of Psychiatry, Yale University, New Haven, CT, USA,CASAColumbia and Departments of Neuroscience and Child Study Center, Yale University, New Haven, CT, USA
| | | | - Richard E Carson
- Department of Radiology and Biomedical Imaging, Yale University, New Haven, CT, USA
| | - David Matuskey
- Department of Radiology and Biomedical Imaging, Yale University, New Haven, CT, USA,Department of Psychiatry, Yale University, New Haven, CT, USA,Departments of Psychiatry and Diagnostic Radiology, Yale School of Medicine, 801 Howard Ave, New Haven, CT 06520, USA, Tel: +1 203 737 6316, Fax: +1 203 785 2994, E-mail:
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14
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Matuskey D, Worhunksy P, Correa E, Pittman B, Gallezot JD, Nabulsi N, Ropchan J, Sreeram V, Gudepu R, Gaiser E, Cosgrove K, Ding YS, Potenza MN, Huang Y, Malison RT, Carson RE. Age-related changes in binding of the D2/3 receptor radioligand [(11)C](+)PHNO in healthy volunteers. Neuroimage 2016; 130:241-247. [PMID: 26876475 DOI: 10.1016/j.neuroimage.2016.02.002] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2015] [Revised: 01/06/2016] [Accepted: 02/04/2016] [Indexed: 11/29/2022] Open
Abstract
OBJECTIVE Previous imaging studies with positron emission tomography (PET) have reliably demonstrated an age-associated decline in the dopamine system. Most of these studies have focused on the densities of dopamine receptor subtypes D2/3R (D2R family) in the striatum using antagonist radiotracers that are largely nonselective for D2R vs. D3R subtypes. Therefore, less is known about any possible age effects in D3-rich extrastriatal areas such as the substantia nigra/ventral tegmental area (SN/VTA) and hypothalamus. This study sought to investigate whether the receptor availability measured with [(11)C](+)PHNO, a D3R-preferring agonist radiotracer, also declines with age. METHODS Forty-two healthy control subjects (9 females, 33 males; age range 19-55 years) were scanned with [(11)C](+)PHNO using a High Resolution Research Tomograph (HRRT). Parametric images were computed using the simplified reference tissue model (SRTM2) with cerebellum as the reference region. Binding potentials (BPND) were calculated for the amygdala, caudate, hypothalamus, pallidum, putamen, SN/VTA, thalamus, and ventral striatum and then confirmed at the voxel level with whole-brain parametric images. RESULTS Regional [(11)C](+)PHNO BPND displayed a negative correlation between receptor availability and age in the caudate (r=-0.56, corrected p=0.0008) and putamen (r=-0.45, corrected p=0.02) in healthy subjects (respectively 8% and 5% lower per decade). No significant correlations with age were found between age and other regions (including the hypothalamus and SN/VTA). Secondary whole-brain voxel-wise analysis confirmed these ROI findings of negative associations and further identified a positive correlation in midbrain (SN/VTA) regions. CONCLUSION In accordance with previous studies, the striatum (an area rich in D2R) is associated with age-related declines of the dopamine system. We did not initially find evidence of changes with age in the SN/VTA and hypothalamus, areas previously found to have a predominantly D3R signal as measured with [(11)C](+)PHNO. A secondary analysis did find a significant positive correlation in midbrain (SN/VTA) regions, indicating that there may be differential effects of aging, whereby D2R receptor availability decreases with age while D3R availability stays unchanged or is increased.
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Affiliation(s)
- David Matuskey
- Department of Radiology and Biomedical Imaging, Yale University, New Haven, CT, USA; Department of Psychiatry, Yale University, New Haven, CT, USA.
| | - Patrick Worhunksy
- Department of Radiology and Biomedical Imaging, Yale University, New Haven, CT, USA
| | - Elizabeth Correa
- Department of Radiology and Biomedical Imaging, Yale University, New Haven, CT, USA
| | - Brian Pittman
- Department of Psychiatry, Yale University, New Haven, CT, USA
| | | | - Nabeel Nabulsi
- Department of Radiology and Biomedical Imaging, Yale University, New Haven, CT, USA
| | - Jim Ropchan
- Department of Radiology and Biomedical Imaging, Yale University, New Haven, CT, USA
| | - Venkatesh Sreeram
- Department of Radiology and Biomedical Imaging, Yale University, New Haven, CT, USA
| | - Rohit Gudepu
- Department of Radiology and Biomedical Imaging, Yale University, New Haven, CT, USA
| | - Edward Gaiser
- Department of Radiology and Biomedical Imaging, Yale University, New Haven, CT, USA; Department of Psychiatry, Yale University, New Haven, CT, USA
| | - Kelly Cosgrove
- Department of Radiology and Biomedical Imaging, Yale University, New Haven, CT, USA; Department of Psychiatry, Yale University, New Haven, CT, USA
| | - Yu-Shin Ding
- Department of Radiology, New York University School of Medicine, New York, NY, USA; Department of Psychiatry, New York University School of Medicine, New York, NY, USA
| | - Marc N Potenza
- Department of Psychiatry, Yale University, New Haven, CT, USA; Department of Neurobiology, Yale University, New Haven, CT, USA; Department ofChild Study Center, Yale University, New Haven, CT, USA
| | - Yiyun Huang
- Department of Radiology and Biomedical Imaging, Yale University, New Haven, CT, USA
| | | | - Richard E Carson
- Department of Radiology and Biomedical Imaging, Yale University, New Haven, CT, USA
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15
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Pike VW. Considerations in the Development of Reversibly Binding PET Radioligands for Brain Imaging. Curr Med Chem 2016; 23:1818-69. [PMID: 27087244 PMCID: PMC5579844 DOI: 10.2174/0929867323666160418114826] [Citation(s) in RCA: 130] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2016] [Revised: 04/04/2016] [Accepted: 04/15/2016] [Indexed: 12/17/2022]
Abstract
The development of reversibly binding radioligands for imaging brain proteins in vivo, such as enzymes, neurotransmitter transporters, receptors and ion channels, with positron emission tomography (PET) is keenly sought for biomedical studies of neuropsychiatric disorders and for drug discovery and development, but is recognized as being highly challenging at the medicinal chemistry level. This article aims to compile and discuss the main considerations to be taken into account by chemists embarking on programs of radioligand development for PET imaging of brain protein targets.
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Affiliation(s)
- Victor W Pike
- Molecular Imaging Branch, National Institute of Mental Health, National Institutes of Health, Rm. B3C346A, 10 Center Drive, Bethesda, MD 20892, USA.
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16
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Abstract
The glutamate and dopamine hypotheses are leading theories of the pathoaetiology of schizophrenia. Both were initially based on indirect evidence from pharmacological studies supported by post-mortem findings, but have since been substantially advanced by new lines of evidence from in vivo imaging studies. This review provides an update on the latest findings on dopamine and glutamate abnormalities in schizophrenia, focusing on in vivo neuroimaging studies in patients and clinical high-risk groups, and considers their implications for understanding the biology and treatment of schizophrenia. These findings have refined both the dopamine and glutamate hypotheses, enabling greater anatomical and functional specificity, and have been complemented by preclinical evidence showing how the risk factors for schizophrenia impact on the dopamine and glutamate systems. The implications of this new evidence for understanding the development and treatment of schizophrenia are considered, and the gaps in current knowledge highlighted. Finally, the evidence for an integrated model of the interactions between the glutamate and dopamine systems is reviewed, and future directions discussed.
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Affiliation(s)
- Oliver Howes
- Psychiatric Imaging, MRC Clinical Sciences Centre, Hammersmith Hospital, London, UK Institute of Psychiatry, King's College London, London, UK
| | - Rob McCutcheon
- Psychiatric Imaging, MRC Clinical Sciences Centre, Hammersmith Hospital, London, UK Institute of Psychiatry, King's College London, London, UK
| | - James Stone
- Psychiatric Imaging, MRC Clinical Sciences Centre, Hammersmith Hospital, London, UK Institute of Psychiatry, King's College London, London, UK
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17
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Sromek AW, Zhang S, Akurathi V, Packard AB, Li W, Alagille D, Morley TJ, Baldwin R, Tamagnan G, Neumeyer JL. Convenient synthesis of 18F-radiolabeled R-(-)-N-n-propyl-2-(3-fluoropropanoxy-11-hydroxynoraporphine. J Labelled Comp Radiopharm 2014; 57:725-9. [PMID: 25400260 DOI: 10.1002/jlcr.3246] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2014] [Revised: 10/21/2014] [Accepted: 10/23/2014] [Indexed: 01/17/2023]
Abstract
Aporphines are attractive candidates for imaging D2 receptor function because, as agonists rather than antagonists, they are selective for the receptor in the high affinity state. In contrast, D2 antagonists do not distinguish between the high and low affinity states, and in vitro data suggests that this distinction may be important in studying diseases characterized by D2 dysregulation, such as schizophrenia and Parkinson's disease. Accordingly, MCL-536 (R-(-)-N-n-propyl-2-(3-[(18)F]fluoropropanoxy-11-hydroxynoraporphine) was selected for labeling with (18)F based on in vitro data obtained for the non-radioactive ((19)F) compound. Fluorine-18-labeled MCL-536 was synthesized in 70% radiochemical yield, >99% radiochemical purity, and specific activity of 167 GBq/µmol (4.5 Ci/µmol) using p-toluenesulfonyl (tosyl) both as a novel protecting group for the phenol and a leaving group for the radiofluorination.
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Affiliation(s)
- Anna W Sromek
- Alcohol and Drug Abuse Research Center, McLean Hospital, Harvard Medical School, 115 Mill Street, Belmont, MA, 02478-9106, USA
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18
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Matuskey D, Gallezot JD, Pittman B, Williams W, Wanyiri J, Gaiser E, Lee DE, Hannestad J, Lim K, Zheng MQ, Lin SF, Labaree D, Potenza MN, Carson RE, Malison RT, Ding YS. Dopamine D₃ receptor alterations in cocaine-dependent humans imaged with [¹¹C](+)PHNO. Drug Alcohol Depend 2014; 139:100-5. [PMID: 24717909 PMCID: PMC4071607 DOI: 10.1016/j.drugalcdep.2014.03.013] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/14/2014] [Revised: 02/21/2014] [Accepted: 03/08/2014] [Indexed: 10/25/2022]
Abstract
BACKGROUND Evidence from animal models and postmortem human studies points to the importance of the dopamine D₃ receptor (D₃R) in cocaine dependence (CD). The objective of this pilot study was to use the D₃R-preferring radioligand [(11)C](+)PHNO to compare receptor availability in groups with and without CD. METHODS Ten medically healthy, non-treatment seeking CD subjects (mean age 41 ± 8) in early abstinence were compared to 10 healthy control (HC) subjects (mean age 41 ± 6) with no history of cocaine or illicit substance abuse. Binding potential (BPND), a measure of available receptors, was determined with parametric images, computed using the simplified reference tissue model (SRTM2) with the cerebellum as the reference region. RESULTS BPND in CD subjects was higher in D₃R-rich areas including the substantia nigra ((SN) 29%; P=0.03), hypothalamus (28%; P=0.02) and amygdala (35%; P=0.03). No between-group differences were observed in the striatum or pallidum. BPND values in the SN (r=+0.83; P=0.008) and pallidum (r=+0.67; P=0.03) correlated with years of cocaine use. CONCLUSIONS Between-group differences suggest an important role for dopaminergic transmission in the SN, hypothalamus and amygdala in CD. Such findings also highlight the potential relevance of D₃R as a medication development target in CD.
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Affiliation(s)
- David Matuskey
- Department of Psychiatry, Yale University, New Haven, CT, USA; Department of Diagnostic Radiology, Yale University, New Haven, CT, USA.
| | | | - Brian Pittman
- Department of Psychiatry, Yale University, New Haven, CT, USA
| | - Wendol Williams
- Department of Psychiatry, Yale University, New Haven, CT, USA,Department of Diagnostic Radiology, Yale University, New Haven, CT, USA
| | - Jane Wanyiri
- Department of Psychiatry, Yale University, New Haven, CT, USA
| | - Edward Gaiser
- Department of Psychiatry, Yale University, New Haven, CT, USA
| | - Dianne E. Lee
- Department of Diagnostic Radiology, Yale University, New Haven, CT, USA
| | - Jonas Hannestad
- Department of Psychiatry, Yale University, New Haven, CT, USA
| | - Keunpoong Lim
- Department of Diagnostic Radiology, Yale University, New Haven, CT, USA
| | - Minq-Qiang Zheng
- Department of Diagnostic Radiology, Yale University, New Haven, CT, USA
| | - Shu-fei Lin
- Department of Diagnostic Radiology, Yale University, New Haven, CT, USA
| | - David Labaree
- Department of Diagnostic Radiology, Yale University, New Haven, CT, USA
| | - Marc N. Potenza
- Department of Psychiatry, Yale University, New Haven, CT, USA
| | - Richard E. Carson
- Department of Diagnostic Radiology, Yale University, New Haven, CT, USA
| | | | - Yu-Shin Ding
- Department of Radiology and Psychiatry, New York University School of Medicine, New York, NY, USA
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19
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In vivo imaging of cerebral dopamine D3 receptors in alcoholism. Neuropsychopharmacology 2014; 39:1703-12. [PMID: 24469594 PMCID: PMC4023144 DOI: 10.1038/npp.2014.18] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/22/2013] [Revised: 11/13/2013] [Accepted: 12/11/2013] [Indexed: 01/12/2023]
Abstract
Animal studies support the role of the dopamine D3 receptor (DRD3) in alcohol reinforcement or liking. Sustained voluntary alcohol drinking in rats has been associated with an upregulation of striatal DRD3 gene expression and selective blockade of DRD3 reduces ethanol preference, consumption, and cue-induced reinstatement. In vivo measurement of DRD3 in the living human brain has not been possible until recently owing to a lack of suitable tools. In this study, DRD3 status was assessed for the first time in human alcohol addiction. Brain DRD3 availability was compared between 16 male abstinent alcohol-dependent patients and 13 healthy non-dependent age-matched males using the DRD3-preferring agonist positron emission tomography (PET) radioligand [(11)C]PHNO with and without blockade with a selective DRD3 antagonist (GSK598809 60 mg p.o.). In striatal regions of interest, where the [(11)C]PHNO PET signal represents primarily DRD2 binding, no differences were seen in [(11)C]PHNO binding between the groups at baseline. However, baseline [(11)C]PHNO binding was higher in alcohol-dependent patients in hypothalamus (VT: 16.5 ± 4 vs 13.7 ± 2.9, p = 0.040), a region in which the [(11)C]PHNO signal almost entirely reflects DRD3 availability. The reductions in regional receptor binding (VT) following a single oral dose of GSK598809 (60 mg) were consistent with those observed in previous studies across all regions. There were no differences in regional changes in VT following DRD3 blockade between the two groups, indicating that the regional fractions of DRD3 are similar in the two groups, and the increased [(11)C]PHNO binding in the hypothalamus in alcohol-dependent patients is explained by elevated DRD3 in this group. Although we found no difference between alcohol-dependent patients and controls in striatal DRD3 levels, increased DRD3 binding in the hypothalamus of alcohol-dependent patients was observed. This may be relevant to the development of future therapeutic strategies to treat alcohol abuse.
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20
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Seeman MV, Seeman P. Is schizophrenia a dopamine supersensitivity psychotic reaction? Prog Neuropsychopharmacol Biol Psychiatry 2014; 48:155-60. [PMID: 24128684 PMCID: PMC3858317 DOI: 10.1016/j.pnpbp.2013.10.003] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/30/2013] [Revised: 10/03/2013] [Accepted: 10/03/2013] [Indexed: 12/22/2022]
Abstract
Adolf Meyer (1866-1950) did not see schizophrenia as a discrete disorder with a specific etiology but, rather, as a reaction to a wide variety of biopsychosocial factors. He may have been right. Today, we have evidence that gene mutations, brain injury, drug use (cocaine, amphetamine, marijuana, phencyclidine, and steroids), prenatal infection and malnutrition, social isolation and marginalization, can all result in the signs and symptoms of schizophrenia. This clinical picture is generally associated with supersensitivity to dopamine, and activates dopamine neurotransmission that is usually alleviated or blocked by drugs that block dopamine D2 receptors. While the dopamine neural pathway may be a final common route to many of the clinical symptoms, the components of this pathway, such as dopamine release and number of D2 receptors, are approximately normal in schizophrenia patients who are in remission. Postmortem findings, however, reveal more dimers of D1D2 and D2D2 receptors in both human schizophrenia brains and in animal models of schizophrenia. Another finding in animal models is an elevation of high-affinity state D2High receptors, but no radioactive ligand is yet available to selectively label D2High receptors in humans. It is suggested that synaptic dopamine supersensitivity in schizophrenia is an attempt at compensation for the original damage by heightening dopamine neurotransmission pathways (preparing the organism for fight or flight). The dopamine overactivity is experienced subjectively as overstimulation, which accounts for some of the clinical symptoms, with attempts at dampening down the stimulation leading to still other symptoms. Reaction and counter-reaction may explain the symptoms of schizophrenia.
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Affiliation(s)
- Mary V. Seeman
- Departments of Psychiatry, University of Toronto, 260 Heath St. West, Suite 605, Toronto, Ontario M5P 3L6, Canada
| | - Philip Seeman
- Departments of Pharmacology, University of Toronto, 260 Heath St. West, Suite 605, Toronto, Ontario M5P 3L6, Canada,Corresponding author. Tel.: +1 416 486 3456. (P. Seeman)
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21
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van Wieringen JP, Shalgunov V, Janssen HM, Fransen PM, Janssen AGM, Michel MC, Booij J, Elsinga PH. Synthesis and characterization of a novel series of agonist compounds as potential radiopharmaceuticals for imaging dopamine D₂/₃ receptors in their high-affinity state. J Med Chem 2014; 57:391-410. [PMID: 24325578 DOI: 10.1021/jm401384w] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Imaging of dopamine D2/3 receptors (D2/3R) can shed light on the nature of several neuropsychiatric disorders in which dysregulation of D2/3R signaling is involved. Agonist D2/3 tracers for PET/SPECT imaging are considered to be superior to antagonists because they are more sensitive to dopamine concentrations and may selectively label the high-affinity receptor state. Carbon-11-labeled D2/3R agonists have been developed, but these short-lived tracers can be used only in centers with a cyclotron. Here, we report the development of a series of novel D2R agonist compounds based on the 2-aminomethylchromane (AMC) scaffold that provides ample opportunities for the introduction of longer-lived [(18)F] or [(123)I]. Binding experiments showed that several AMC compounds have a high affinity and selectivity for D2/3R and act as agonists. Two fluorine-containing compounds were [(18)F]-labeled, and both displayed specific binding to striatal D2/3R in rat brain slices in vitro. These findings encourage further in vivo evaluations.
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Affiliation(s)
- Jan-Peter van Wieringen
- Department of Nuclear Medicine, Academic Medical Center, University of Amsterdam , Amsterdam, The Netherlands
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22
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Seeman P. Are dopamine D2 receptors out of control in psychosis? Prog Neuropsychopharmacol Biol Psychiatry 2013; 46:146-52. [PMID: 23880595 DOI: 10.1016/j.pnpbp.2013.07.006] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/14/2013] [Revised: 07/08/2013] [Accepted: 07/08/2013] [Indexed: 01/11/2023]
Abstract
It is known that schizophrenia patients are behaviorally supersensitive to dopamine-like drugs (amphetamine, methylphenidate). There is evidence for an increased release of dopamine, a slight increase of dopamine D2 receptors and an increase of dopamine D2High receptors in schizophrenia, all possibly explaining the clinical supersensitivity to dopamine. The elevation in apparent D2High receptors in vivo in schizophrenia matches the elevation in D2High receptors in many animal models of psychosis. The increased amounts of D2High receptors in psychotic-like behavior in animals may result from a loss of control of D2 by various factors. These factors include the rate of phosphorylation and desensitization of D2 receptors by kinases, the attachment of arrestin to D2 receptors, internalization of D2 receptors, the rate of receptor de-phosphorylation, formation of D2 receptor dimers, and GTP regulation by various GTPases. While at present there are no statistically significant associations of any of these controlling factors and their genes with schizophrenia, investigation of D2High receptors in schizophrenia will require a new radioligand in order to selectively label D2High receptors in vivo in patients. Finally, haloperidol reduces the number of D2High receptors that are elevated by amphetamine, indicating that this therapeutic effect may occur clinically.
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Affiliation(s)
- Philip Seeman
- Department of Pharmacology, University of Toronto, 260 Heath Street, West, unit 605, Toronto, Ontario M5P 3L6, Canada; Department of Psychiatry, University of Toronto, 260 Heath Street, West, unit 605, Toronto, Ontario, M5P 3L6, Canada.
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23
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Seeman P. Schizophrenia and dopamine receptors. Eur Neuropsychopharmacol 2013; 23:999-1009. [PMID: 23860356 DOI: 10.1016/j.euroneuro.2013.06.005] [Citation(s) in RCA: 82] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/07/2012] [Revised: 04/06/2013] [Accepted: 06/24/2013] [Indexed: 02/06/2023]
Abstract
Schizophrenia patients are behaviorally supersensitive to dopamine-like drugs such as amphetamine or methylphenidate, meaning that patients respond to such drugs with increased psychotic symptoms, as compared to control subjects. A basis of such supersensitivity may be an increased pre-synaptic release of dopamine or a post-synaptic elevation of D2 receptors or of D2High receptors in active stages of schizophrenia. While the pre-synaptic release of dopamine is normal in stable patients with schizophrenia, brain imaging studies find that D2 receptors are increased by an average of 5.8% in antipsychotic-free schizophrenia patients. It is possible that the behavioral supersensitivity may stem from more D2High receptors in schizophrenia. Although the antipsychotic/dopamine D2 receptor can exist in vitro in a state of high affinity for dopamine (as D2High), or in a state of low affinity for dopamine (as D2Low), there is no clear evidence that D2High states can be selectively labeled or stably exist in vivo. Nevertheless, two studies revealed an 80% increase in apparent D2High receptors in schizophrenia patients after reducing endogenous dopamine. The elevation in apparent D2High receptors in vivo in schizophrenia matches the elevation in D2High receptors in vitro in animal models of psychosis, including dopamine-supersensitive animals pretreated with amphetamine, marijuana, or phencyclidine, or animals with gene knockouts in various neurotransmitter pathways, including those for glutamate receptors. The elevation of D2High receptors in vitro and the increased apparent D2High receptors in vivo is consistent with behavioral dopamine supersensitivity in schizophrenia patients.
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Affiliation(s)
- Philip Seeman
- Department of Psychiatry, University of Toronto, 260 Heath Street, West, Unit 605, Toronto, Ont., Canada M5P 3L6; Department of Pharmacology, University of Toronto, 260 Heath Street, West, Unit 605, Toronto, Ont., Canada M5P 3L6.
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Suridjan I, Rusjan P, Addington J, Wilson AA, Houle S, Mizrahi R. Dopamine D2 and D3 binding in people at clinical high risk for schizophrenia, antipsychotic-naive patients and healthy controls while performing a cognitive task. J Psychiatry Neurosci 2013; 38:98-106. [PMID: 23010256 PMCID: PMC3581597 DOI: 10.1503/jpn.110181] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
Abstract
BACKGROUND The dopamine (DA) D2 receptors exist in 2 states: a high-affinity state (D2 high) that is linked to second messenger systems, responsible for functional effects, exhibits high affinity for agonists (e.g., DA), and a low-affinity state that is functionally inert exhibits lower affinity for agonists. The DA D3 receptor subtype exhibits high agonist affinity, whereas the existence of the multiple affinity states is controversial. Preclinical studies in animal models of psychosis have shown a selective increase of D2 high as the common factor in psychosis, and the D3 receptor has been suggested to be involved in the pathophysiology of schizophrenia. METHODS We studied D2 high and D3 in people at clinical high risk (CHR) for schizophrenia and in antipsychotic-naive patients with schizophrenia using the novel positron emission tomography radiotracer, [11C]-(+)-PHNO. The binding potential nondisplaceable (BP(ND)) was examined in the regions of interest (ROI; caudate, putamen, ventral striatum, globus pallidus, substantia nigra and thalamus) using an ROI and a voxel-wise approach while participants performed a cognitive task. RESULTS We recruited 12 CHR individuals and 13 antipsychotic-naive patients with schizophrenia-spectrum disorder, whom we compared with 12 age- and sex-matched healthy controls. The BP(ND) between patients and controls did not differ in any of the ROIs, consistent with the voxel-wise analysis. Correlations between the BP(ND) in D3-rich regions and psychopathology warrant further investigation. LIMITATIONS In the absence of resting-state (baseline) BP(ND) data, or following a depletion paradigm (i.e., α-methyl partyrosine), it is not possible to ascertain whether the lack of difference among the groups is owing to different levels of baseline DA or to release during the cognitive task. CONCLUSION To our knowledge, the present study represents the first effort to measure the D2 and D3 receptors under a cognitive challenge in individuals putative/prodromal for schizophrenia using [11C]-(+)-PHNO.
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Affiliation(s)
| | | | | | | | | | - Romina Mizrahi
- Correspondence to: R. Mizrahi, PET Centre, Centre for Addiction and Mental Health, 250 College St., Toronto ON M5T 1R8;
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Madras BK. History of the discovery of the antipsychotic dopamine D2 receptor: a basis for the dopamine hypothesis of schizophrenia. JOURNAL OF THE HISTORY OF THE NEUROSCIENCES 2013; 22:62-78. [PMID: 23323533 DOI: 10.1080/0964704x.2012.678199] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
The 1975 publication of Seeman et al. (Proc Nat Acad Sci, USA), reporting the discovery of the antipsychotic receptor in the brain, is a classic example of translational medicine research. In searching for a pathophysiological mechanism of psychosis, the team sought to identify sites that bound the antipsychotic drug haloperidol. Their criterion was that haloperidol bound to the site at one to two nanomoles per liter, corresponding to haloperidol concentrations found in spinal fluid or plasma water in treated patients. They requested de novo synthesis of tritiated haloperidol, and it readily detected specific haloperidol binding sites in brain striatum. With dopamine binding the haloperidol-labeled sites with higher potency than other neurotransmitters, the sites were named antipsychotic/dopamine receptors (now designated dopamine D2 receptors). Most significantly, they found that all antipsychotics bound these sites at concentrations and with a rank order of potencies that were directly related to the mean daily antipsychotic dose taken by patients with schizophrenia. Their findings enabled screening for new antipsychotics, initiated D2 receptor measurements in brain of living patients, and determination of minimum occupancy (65%) of D2 receptors for antipsychotic benefit. The collective work is generally viewed as providing a fundamental basis for the dopamine hypothesis of schizophrenia.
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Affiliation(s)
- Bertha K Madras
- Department of Psychiatry, Harvard Medical School, New England Primate Research Center, Southborough, MA 01772-9102, USA.
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Agonist high- and low-affinity states of dopamine D₂ receptors: methods of detection and clinical implications. Naunyn Schmiedebergs Arch Pharmacol 2012; 386:135-54. [PMID: 23224422 DOI: 10.1007/s00210-012-0817-0] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2012] [Accepted: 11/22/2012] [Indexed: 01/10/2023]
Abstract
Dopamine D(2) receptors, similar to other G-protein-coupled receptors, exist in a high- and low-affinity state for agonists. Based upon a review of the methods for detecting D(2) receptor agonist high-affinity states, we discuss alterations of such states in animal models of disease and the implications of such alterations for their labelling with positron emission tomography (PET) and single-photon emission computed tomography (SPECT) tracers. The classic approach of detecting agonist high-affinity states compares agonist competition for antagonist radioligands, in most cases using [(3)H]-spiperone as the radioligand; alternative approaches and radioligands have been proposed, but their claimed advantages have not been substantiated by other investigators. In view of the advantages and disadvantages of various techniques, we critically have reviewed reported findings on the detection of D(2) receptor agonist high-affinity states in a variety of animal models. These data are compared to the less numerous findings from human in vivo studies based on PET and SPECT tracers; they are interpreted in light of the finding that D(2) receptor agonist high-affinity states under control conditions may differ between rodent and human brain. The potential advantages of agonist ligands in studies of pathophysiology and as diagnostics are being discussed.
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Saijo T, Maeda J, Okauchi T, Maeda JI, Morio Y, Kuwahara Y, Suzuki M, Goto N, Fukumura T, Suhara T, Higuchi M. Presynaptic selectivity of a ligand for serotonin 1A receptors revealed by in vivo PET assays of rat brain. PLoS One 2012; 7:e42589. [PMID: 22880045 PMCID: PMC3413639 DOI: 10.1371/journal.pone.0042589] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2012] [Accepted: 07/10/2012] [Indexed: 11/19/2022] Open
Abstract
A novel investigational antidepressant with high affinity for the serotonin transporter and the serotonin 1A (5-HT(1A)) receptor, called Wf-516 (structural formula: (2S)-1-[4-(3,4-dichlorophenyl)piperidin-1-yl]-3-[2-(5-methyl-1,3,4-oxadiazol-2-yl)benzo[b]furan-4-yloxy]propan-2-ol monohydrochloride), has been found to exert a rapid therapeutic effect, although the mechanistic basis for this potential advantage remains undetermined. We comparatively investigated the pharmacokinetics and pharmacodynamics of Wf-516 and pindolol by positron emission tomographic (PET) and autoradiographic assays of rat brains in order to elucidate their molecular interactions with presynaptic and postsynaptic 5-HT(1A) receptors. In contrast to the full receptor occupancy by pindolol in PET measurements, the binding of Wf-516 to 5-HT(1A) receptors displayed limited capacity, with relatively high receptor occupancy being achieved in regions predominantly containing presynaptic receptors. This selectivity was further proven by PET scans of neurotoxicant-treated rats deficient in presynaptic 5-HT(1A) receptors. In addition, [(35)S]guanosine 5'-O-[γ-thio]triphosphate autoradiography indicated a partial agonistic ability of Wf-516 for 5-HT(1A) receptors. This finding has lent support to reports that diverse partial agonists for 5-HT(1A) receptors exert high sensitivity for presynaptic components. Thus, the present PET data suggest a relatively high capacity of presynaptic binding sites for partial agonists. Since our in vitro and ex vivo autoradiographies failed to illustrate these distinct features of Wf-516, in vivo PET imaging is considered to be, thus far, the sole method capable of pharmacokinetically demonstrating the unique actions of Wf-516 and similar new-generation antidepressants.
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Affiliation(s)
- Takeaki Saijo
- Molecular Imaging Center, National Institute of Radiological Sciences, Chiba, Japan
- Department of Molecular Neuroimaging, Tohoku University School of Medicine, Sendai, Japan
- DMPK Research Laboratory, Mitsubishi Tanabe Pharma Corporation, Kisarazu, Japan
| | - Jun Maeda
- Molecular Imaging Center, National Institute of Radiological Sciences, Chiba, Japan
| | - Takashi Okauchi
- Molecular Imaging Center, National Institute of Radiological Sciences, Chiba, Japan
| | - Jun-ichi Maeda
- Research Quality Assurance Department, Mitsubishi Tanabe Pharma Corporation, Yokohama, Japan
| | - Yasunori Morio
- Development Project Management Department, Mitsubishi Tanabe Pharma Corporation, Tokyo, Japan
| | - Yasuhiro Kuwahara
- Advanced Medical Research Laboratory, Mitsubishi Tanabe Pharma Corporation, Yokohama, Japan
| | - Masayuki Suzuki
- DMPK Research Laboratory, Mitsubishi Tanabe Pharma Corporation, Kisarazu, Japan
| | - Nobuharu Goto
- Early Stage Clinical Research Center, Mitsubishi Tanabe Pharma Corporation, Tokyo, Japan
| | - Toshimitsu Fukumura
- Molecular Imaging Center, National Institute of Radiological Sciences, Chiba, Japan
| | - Tetsuya Suhara
- Molecular Imaging Center, National Institute of Radiological Sciences, Chiba, Japan
- Department of Molecular Neuroimaging, Tohoku University School of Medicine, Sendai, Japan
| | - Makoto Higuchi
- Molecular Imaging Center, National Institute of Radiological Sciences, Chiba, Japan
- Department of Molecular Neuroimaging, Tohoku University School of Medicine, Sendai, Japan
- * E-mail:
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