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Interaction of Ligands for PET with the Dopamine D3 Receptor: In Silico and In Vitro Methods. Biomolecules 2021; 11:biom11040529. [PMID: 33918451 PMCID: PMC8065765 DOI: 10.3390/biom11040529] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2021] [Revised: 03/25/2021] [Accepted: 03/31/2021] [Indexed: 12/28/2022] Open
Abstract
[18F]Fallypride and [18F]Fluortriopride (FTP) are two different PET radiotracers that bind with sub-nanomolar affinity to the dopamine D3 receptor (D3R). In spite of their similar D3 affinities, the two PET ligands display very different properties for labeling the D3R in vivo: [18F]Fallypride is capable of binding to D3R under "baseline" conditions, whereas [18F]FTP requires the depletion of synaptic dopamine in order to image the receptor in vivo. These data suggest that [18F]Fallypride is able to compete with synaptic dopamine for binding to the D3R, whereas [18F]FTP is not. The goal of this study was to conduct a series of docking and molecular dynamic simulation studies to identify differences in the ability of each molecule to interact with the D3R that could explain these differences with respect to competition with synaptic dopamine. Competition studies measuring the ability of each ligand to compete with dopamine in the β-arrestin assay were also conducted. The results of the in silico studies indicate that FTP has a weaker interaction with the orthosteric binding site of the D3R versus that of Fallypride. The results of the in silico studies were also consistent with the IC50 values of each compound in the dopamine β-arrestin competition assays. The results of this study indicate that in silico methods may be able to predict the ability of a small molecule to compete with synaptic dopamine for binding to the D3R.
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Prasad K, de Vries EFJ, Elsinga PH, Dierckx RAJO, van Waarde A. Allosteric Interactions between Adenosine A 2A and Dopamine D 2 Receptors in Heteromeric Complexes: Biochemical and Pharmacological Characteristics, and Opportunities for PET Imaging. Int J Mol Sci 2021; 22:ijms22041719. [PMID: 33572077 PMCID: PMC7915359 DOI: 10.3390/ijms22041719] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2021] [Revised: 02/02/2021] [Accepted: 02/03/2021] [Indexed: 12/17/2022] Open
Abstract
Adenosine and dopamine interact antagonistically in living mammals. These interactions are mediated via adenosine A2A and dopamine D2 receptors (R). Stimulation of A2AR inhibits and blockade of A2AR enhances D2R-mediated locomotor activation and goal-directed behavior in rodents. In striatal membrane preparations, adenosine decreases both the affinity and the signal transduction of D2R via its interaction with A2AR. Reciprocal A2AR/D2R interactions occur mainly in striatopallidal GABAergic medium spiny neurons (MSNs) of the indirect pathway that are involved in motor control, and in striatal astrocytes. In the nucleus accumbens, they also take place in MSNs involved in reward-related behavior. A2AR and D2R co-aggregate, co-internalize, and co-desensitize. They are at very close distance in biomembranes and form heteromers. Antagonistic interactions between adenosine and dopamine are (at least partially) caused by allosteric receptor–receptor interactions within A2AR/D2R heteromeric complexes. Such interactions may be exploited in novel strategies for the treatment of Parkinson’s disease, schizophrenia, substance abuse, and perhaps also attention deficit-hyperactivity disorder. Little is known about shifting A2AR/D2R heteromer/homodimer equilibria in the brain. Positron emission tomography with suitable ligands may provide in vivo information about receptor crosstalk in the living organism. Some experimental approaches, and strategies for the design of novel imaging agents (e.g., heterobivalent ligands) are proposed in this review.
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Affiliation(s)
- Kavya Prasad
- Department of Nuclear Medicine and Molecular Imaging, University Medical Center Groningen, University of Groningen, Hanzeplein 1, 9713GZ Groningen, The Netherlands; (E.F.J.d.V.); (P.H.E.); (R.A.J.O.D.)
- Correspondence: (K.P.); (A.v.W.); Tel.: +31-50-3613215
| | - Erik F. J. de Vries
- Department of Nuclear Medicine and Molecular Imaging, University Medical Center Groningen, University of Groningen, Hanzeplein 1, 9713GZ Groningen, The Netherlands; (E.F.J.d.V.); (P.H.E.); (R.A.J.O.D.)
| | - Philip H. Elsinga
- Department of Nuclear Medicine and Molecular Imaging, University Medical Center Groningen, University of Groningen, Hanzeplein 1, 9713GZ Groningen, The Netherlands; (E.F.J.d.V.); (P.H.E.); (R.A.J.O.D.)
| | - Rudi A. J. O. Dierckx
- Department of Nuclear Medicine and Molecular Imaging, University Medical Center Groningen, University of Groningen, Hanzeplein 1, 9713GZ Groningen, The Netherlands; (E.F.J.d.V.); (P.H.E.); (R.A.J.O.D.)
- Department of Diagnostic Sciences, Ghent University Faculty of Medicine and Health Sciences, C.Heymanslaan 10, 9000 Gent, Belgium
| | - Aren van Waarde
- Department of Nuclear Medicine and Molecular Imaging, University Medical Center Groningen, University of Groningen, Hanzeplein 1, 9713GZ Groningen, The Netherlands; (E.F.J.d.V.); (P.H.E.); (R.A.J.O.D.)
- Correspondence: (K.P.); (A.v.W.); Tel.: +31-50-3613215
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Kilbourn MR. 11C- and 18F-Radiotracers for In Vivo Imaging of the Dopamine System: Past, Present and Future. Biomedicines 2021; 9:108. [PMID: 33499179 PMCID: PMC7912183 DOI: 10.3390/biomedicines9020108] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2020] [Revised: 01/17/2021] [Accepted: 01/19/2021] [Indexed: 12/17/2022] Open
Abstract
The applications of positron emission tomography (PET) imaging to study brain biochemistry, and in particular the aspects of dopamine neurotransmission, have grown significantly over the 40 years since the first successful in vivo imaging studies in humans. In vivo PET imaging of dopaminergic functions of the central nervous system (CNS) including dopamine synthesis, vesicular storage, synaptic release and receptor binding, and reuptake processes, are now routinely used for studies in neurology, psychiatry, drug abuse and addiction, and drug development. Underlying these advances in PET imaging has been the development of the unique radiotracers labeled with positron-emitting radionuclides such as carbon-11 and fluorine-18. This review focuses on a selection of the more accepted and utilized PET radiotracers currently available, with a look at their past, present and future.
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Affiliation(s)
- Michael R Kilbourn
- Department of Radiology, University of Michigan Medical School, Ann Arbor, MI 48105, USA
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Sander CY, Hansen HD, Wey HY. Advances in simultaneous PET/MR for imaging neuroreceptor function. J Cereb Blood Flow Metab 2020; 40:1148-1166. [PMID: 32169011 PMCID: PMC7238372 DOI: 10.1177/0271678x20910038] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Hybrid imaging using PET/MRI has emerged as a platform for elucidating novel neurobiology, molecular and functional changes in disease, and responses to physiological or pharmacological interventions. For the central nervous system, PET/MRI has provided insights into biochemical processes, linking selective molecular targets and distributed brain function. This review highlights several examples that leverage the strengths of simultaneous PET/MRI, which includes measuring the perturbation of multi-modal imaging signals on dynamic timescales during pharmacological challenges, physiological interventions or behavioral tasks. We discuss important considerations for the experimental design of dynamic PET/MRI studies and data analysis approaches for comparing and quantifying simultaneous PET/MRI data. The primary focus of this review is on functional PET/MRI studies of neurotransmitter and receptor systems, with an emphasis on the dopamine, opioid, serotonin and glutamate systems as molecular neuromodulators. In this context, we provide an overview of studies that employ interventions to alter the activity of neuroreceptors or the release of neurotransmitters. Overall, we emphasize how the synergistic use of simultaneous PET/MRI with appropriate study design and interventions has the potential to expand our knowledge about the molecular and functional dynamics of the living human brain. Finally, we give an outlook on the future opportunities for simultaneous PET/MRI.
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Affiliation(s)
- Christin Y Sander
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, MA, USA
| | - Hanne D Hansen
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, MA, USA.,Neurobiology Research Unit and NeuroPharm, Copenhagen University Hospital (Rigshospitalet), Copenhagen, Denmark
| | - Hsiao-Ying Wey
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, MA, USA
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Ermert J, Benešová M, Hugenberg V, Gupta V, Spahn I, Pietzsch HJ, Liolios C, Kopka K. Radiopharmaceutical Sciences. Clin Nucl Med 2020. [DOI: 10.1007/978-3-030-39457-8_2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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Franco Machado J, Silva RD, Melo R, G Correia JD. Less Exploited GPCRs in Precision Medicine: Targets for Molecular Imaging and Theranostics. Molecules 2018; 24:E49. [PMID: 30583594 PMCID: PMC6337414 DOI: 10.3390/molecules24010049] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2018] [Revised: 12/07/2018] [Accepted: 12/09/2018] [Indexed: 12/18/2022] Open
Abstract
Precision medicine relies on individually tailored therapeutic intervention taking into account individual variability. It is strongly dependent on the availability of target-specific drugs and/or imaging agents that recognize molecular targets and patient-specific disease mechanisms. The most sensitive molecular imaging modalities, Single Photon Emission Computed Tomography (SPECT) and Positron Emission Tomography (PET), rely on the interaction between an imaging radioprobe and a target. Moreover, the use of target-specific molecular tools for both diagnostics and therapy, theranostic agents, represent an established methodology in nuclear medicine that is assuming an increasingly important role in precision medicine. The design of innovative imaging and/or theranostic agents is key for further accomplishments in the field. G-protein-coupled receptors (GPCRs), apart from being highly relevant drug targets, have also been largely exploited as molecular targets for non-invasive imaging and/or systemic radiotherapy of various diseases. Herein, we will discuss recent efforts towards the development of innovative imaging and/or theranostic agents targeting selected emergent GPCRs, namely the Frizzled receptor (FZD), Ghrelin receptor (GHSR-1a), G protein-coupled estrogen receptor (GPER), and Sphingosine-1-phosphate receptor (S1PR). The pharmacological and clinical relevance will be highlighted, giving particular attention to the studies on the synthesis and characterization of targeted molecular imaging agents, biological evaluation, and potential clinical applications in oncology and non-oncology diseases. Whenever relevant, supporting computational studies will be also discussed.
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Affiliation(s)
- João Franco Machado
- Centro de Ciências e Tecnologias Nucleares, Instituto Superior Técnico, Universidade de Lisboa, CTN, Estrada Nacional 10 (km 139,7), 2695-066 Bobadela LRS, Portugal.
- Centro de Química Estrutural, Faculdade de Ciências, Universidade de Lisboa, 1749-016 Lisboa, Portugal.
| | - Rúben D Silva
- Centro de Ciências e Tecnologias Nucleares, Instituto Superior Técnico, Universidade de Lisboa, CTN, Estrada Nacional 10 (km 139,7), 2695-066 Bobadela LRS, Portugal.
| | - Rita Melo
- Centro de Ciências e Tecnologias Nucleares, Instituto Superior Técnico, Universidade de Lisboa, CTN, Estrada Nacional 10 (km 139,7), 2695-066 Bobadela LRS, Portugal.
- Center for Neuroscience and Cell Biology; Rua Larga, Faculdade de Medicina, Polo I, 1ºandar, Universidade de Coimbra, 3004-504 Coimbra, Portugal.
| | - João D G Correia
- Centro de Ciências e Tecnologias Nucleares, Instituto Superior Técnico, Universidade de Lisboa, CTN, Estrada Nacional 10 (km 139,7), 2695-066 Bobadela LRS, Portugal.
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Suh M, Lee DS. Brain Theranostics and Radiotheranostics: Exosomes and Graphenes In Vivo as Novel Brain Theranostics. Nucl Med Mol Imaging 2018; 52:407-419. [PMID: 30538772 PMCID: PMC6261865 DOI: 10.1007/s13139-018-0550-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2018] [Revised: 09/10/2018] [Accepted: 10/05/2018] [Indexed: 12/17/2022] Open
Abstract
Brain disease is one of the greatest threats to public health. Brain theranostics is recently taking shape, indicating the treatments of stroke, inflammatory brain disorders, psychiatric diseases, neurodevelopmental disease, and neurodegenerative disease. However, several factors, such as lack of endophenotype classification, blood-brain barrier (BBB), target determination, ignorance of biodistribution after administration, and complex intercellular communication between brain cells, make brain theranostics application difficult, especially when it comes to clinical application. So, a more thorough understanding of each aspect is needed. In this review, we focus on recent studies regarding the role of exosomes in intercellular communication of brain cells, therapeutic effect of graphene quantum dots, transcriptomics/epitranscriptomics approach for target selection, and in vitro/in vivo considerations.
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Affiliation(s)
- Minseok Suh
- Department of Nuclear Medicine, Seoul National University College of Medicine, Seoul, 03080 Republic of Korea
- Department of Molecular Medicine and Biopharmaceutical Sciences, Graduate School of Convergence Science and Technology, Seoul National University, Seoul, 03080 Republic of Korea
| | - Dong Soo Lee
- Department of Nuclear Medicine, Seoul National University College of Medicine, Seoul, 03080 Republic of Korea
- Department of Molecular Medicine and Biopharmaceutical Sciences, Graduate School of Convergence Science and Technology, Seoul National University, Seoul, 03080 Republic of Korea
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Liow JS, Morse CL, Lu S, Frankland M, Tye GL, Zoghbi SS, Gladding RL, Shaik AB, Innis RB, Newman AH, Pike VW. [ O- methyl- 11C] N-(4-(4-(3-Chloro-2-methoxyphenyl)-piperazin-1-yl)butyl)-1 H-indole-2-carboxamide ([ 11C]BAK4-51) Is an Efflux Transporter Substrate and Ineffective for PET Imaging of Brain D₃ Receptors in Rodents and Monkey. Molecules 2018; 23:molecules23112737. [PMID: 30360553 PMCID: PMC6278341 DOI: 10.3390/molecules23112737] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2018] [Revised: 10/15/2018] [Accepted: 10/18/2018] [Indexed: 11/16/2022] Open
Abstract
Selective high-affinity antagonists for the dopamine D₃ receptor (D₃R) are sought for treating substance use disorders. Positron emission tomography (PET) with an effective D₃R radioligand could be a useful tool for the development of such therapeutics by elucidating pharmacological specificity and target engagement in vivo. Currently, a D₃R-selective radioligand does not exist. The D₃R ligand, N-(4-(4-(3-chloro-2-methoxyphenyl)piperazin-1-yl)butyl)-1H-indole-2-carboxamide (BAK4-51, 1), has attractive properties for PET radioligand development, including full antagonist activity, very high D₃R affinity, D₃R selectivity, and moderate lipophilicity. We labeled 1 with the positron-emitter carbon-11 (t1/2 = 20.4 min) in the methoxy group for evaluation as a radioligand in animals with PET. However, [11C]1 was found to be an avid substrate for brain efflux transporters and lacked D₃R-specific signal in rodent and monkey brain in vivo.
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Affiliation(s)
- Jeih-San Liow
- Molecular Imaging Branch, National Institute of Mental Health, National Institutes of Health, Room B3C346, 10 Center Drive, Bethesda, MD 20892, USA.
| | - Cheryl L Morse
- Molecular Imaging Branch, National Institute of Mental Health, National Institutes of Health, Room B3C346, 10 Center Drive, Bethesda, MD 20892, USA.
| | - Shuiyu Lu
- Molecular Imaging Branch, National Institute of Mental Health, National Institutes of Health, Room B3C346, 10 Center Drive, Bethesda, MD 20892, USA.
| | - Michael Frankland
- Molecular Imaging Branch, National Institute of Mental Health, National Institutes of Health, Room B3C346, 10 Center Drive, Bethesda, MD 20892, USA.
| | - George L Tye
- Molecular Imaging Branch, National Institute of Mental Health, National Institutes of Health, Room B3C346, 10 Center Drive, Bethesda, MD 20892, USA.
| | - Sami S Zoghbi
- Molecular Imaging Branch, National Institute of Mental Health, National Institutes of Health, Room B3C346, 10 Center Drive, Bethesda, MD 20892, USA.
| | - Robert L Gladding
- Molecular Imaging Branch, National Institute of Mental Health, National Institutes of Health, Room B3C346, 10 Center Drive, Bethesda, MD 20892, USA.
| | - Anver B Shaik
- Medicinal Chemistry Section, Molecular Targets and Medications Discovery Branch, National Institute on Drug Abuse, National Institutes of Health, 333 Cassell Drive, Baltimore, MD 21224, USA.
| | - Robert B Innis
- Molecular Imaging Branch, National Institute of Mental Health, National Institutes of Health, Room B3C346, 10 Center Drive, Bethesda, MD 20892, USA.
| | - Amy H Newman
- Medicinal Chemistry Section, Molecular Targets and Medications Discovery Branch, National Institute on Drug Abuse, National Institutes of Health, 333 Cassell Drive, Baltimore, MD 21224, USA.
| | - Victor W Pike
- Molecular Imaging Branch, National Institute of Mental Health, National Institutes of Health, Room B3C346, 10 Center Drive, Bethesda, MD 20892, USA.
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Abstract
Dopamine D3 receptors have key roles in behavioral reward, addiction, Parkinson's disease, and schizophrenia, and there is interest in studying their role in these disorders using PET. However, current PET radiotracers for studying D3 receptors in humans all bind to both D2 and D3 due to similarities between the two receptors. Selective D2 and D3 radioligands would aid investigation of the differences between D2 and D3 circuitry in the central nervous system. While there are currently in vitro measures of ligand D3/D2 selectivity, there is a need for an in vivo PET measure of D3/D2 selectivity. This review discusses current PET imaging of dopamine D2/D3 receptors and proposes methodology for quantitating in vivo selectivity of probes for PET imaging of dopamine D3 receptors.
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Affiliation(s)
- Robert K Doot
- Department of Radiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA.
| | - Jacob G Dubroff
- Department of Radiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Kyle J Labban
- Department of Radiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Robert H Mach
- Department of Radiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
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Nebel N, Maschauer S, Kuwert T, Hocke C, Prante O. In Vitro and In Vivo Characterization of Selected Fluorine-18 Labeled Radioligands for PET Imaging of the Dopamine D3 Receptor. Molecules 2016; 21:molecules21091144. [PMID: 27589704 PMCID: PMC6272905 DOI: 10.3390/molecules21091144] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2016] [Revised: 08/25/2016] [Accepted: 08/26/2016] [Indexed: 02/07/2023] Open
Abstract
Cerebral dopamine D3 receptors seem to play a key role in the control of drug-seeking behavior. The imaging of their regional density with positron emission tomography (PET) could thus help in the exploration of the molecular basis of drug addiction. A fluorine-18 labeled D3 subtype selective radioligand would be beneficial for this purpose; however, as yet, there is no such tracer available. The three candidates [18F]1, [18F]2a and [18F]2b were chosen for in vitro and in vivo characterization as radioligands suitable for selective PET imaging of the D3 receptor. Their evaluation included the analysis of radiometabolites and the assessment of non-specific binding by in vitro rat brain autoradiography. While [18F]1 and [18F]2a revealed high non-specific uptake in in vitro rat brain autoradiography, the D3 receptor density was successfully determined on rat brain sections (n = 4) with the candidate [18F]2b offering a Bmax of 20.38 ± 2.67 pmol/g for the islands of Calleja, 19.54 ± 1.85 pmol/g for the nucleus accumbens and 16.58 ± 1.63 pmol/g for the caudate putamen. In PET imaging studies, the carboxamide 1 revealed low signal/background ratios in the rat brain and relatively low uptake in the pituitary gland, while the azocarboxamides [18F]2a and [18F]2b showed binding that was blockable by the D3 receptor ligand BP897 in the ventricular system and the pituitary gland in PET imaging studies in living rats.
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Affiliation(s)
- Natascha Nebel
- Molecular Imaging and Radiochemistry, Department of Nuclear Medicine, Friedrich Alexander University (FAU), Erlangen 91054, Germany.
| | - Simone Maschauer
- Molecular Imaging and Radiochemistry, Department of Nuclear Medicine, Friedrich Alexander University (FAU), Erlangen 91054, Germany.
| | - Torsten Kuwert
- Molecular Imaging and Radiochemistry, Department of Nuclear Medicine, Friedrich Alexander University (FAU), Erlangen 91054, Germany.
| | - Carsten Hocke
- Molecular Imaging and Radiochemistry, Department of Nuclear Medicine, Friedrich Alexander University (FAU), Erlangen 91054, Germany.
| | - Olaf Prante
- Molecular Imaging and Radiochemistry, Department of Nuclear Medicine, Friedrich Alexander University (FAU), Erlangen 91054, Germany.
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Cortés A, Moreno E, Rodríguez-Ruiz M, Canela EI, Casadó V. Targeting the dopamine D3 receptor: an overview of drug design strategies. Expert Opin Drug Discov 2016; 11:641-64. [PMID: 27135354 DOI: 10.1080/17460441.2016.1185413] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
INTRODUCTION Dopamine is a neurotransmitter widely distributed in both the periphery and the central nervous system (CNS). Its physiological effects are mediated by five closely related G protein-coupled receptors (GPCRs) that are divided into two major subclasses: the D1-like (D1, D5) and the D2-like (D2, D3, D4) receptors. D3 receptors (D3Rs) have the highest density in the limbic areas of the brain, which are associated with cognitive and emotional functions. These receptors are therefore attractive targets for therapeutic management. AREAS COVERED This review summarizes the functional and pharmacological characteristics of D3Rs, including the design and clinical relevance of full agonists, partial agonists and antagonists, as well as the capacity of these receptors to form active homodimers, heterodimers or higher order receptor complexes as pharmacological targets in several neurological and neurodegenerative disorders. EXPERT OPINION The high sequence homology between D3R and the D2-type challenges the development of D3R-selective compounds. The design of new D3R-preferential ligands with improved physicochemical properties should provide a better pharmacokinetic/bioavailability profile and lesser toxicity than is found with existing D3R ligands. It is also essential to optimize D3R affinity and, especially, D3R vs. D2-type binding and functional selectivity ratios. Developing allosteric and bitopic ligands should help to improve the D3R selectivity of these drugs. As most evidence points to the ability of GPCRs to form homomers and heteromers, the most promising therapeutic strategy in the future is likely to involve the application of heteromer-selective drugs. These selective ligands would display different affinities for a given receptor depending on the receptor partners within the heteromer. Therefore, designing novel compounds that specifically target and modulate D1R-D3R heteromers would be an interesting approach for the treatment of levodopa (L-DOPA)-induced dyskinesias.
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Affiliation(s)
- Antoni Cortés
- a Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED) , Spain.,b Department of Biochemistry and Molecular Biomedicine, Faculty of Biology, Institute of Biomedicine of the University of Barcelona (IBUB) , University of Barcelona , Barcelona , Spain
| | - Estefanía Moreno
- a Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED) , Spain.,b Department of Biochemistry and Molecular Biomedicine, Faculty of Biology, Institute of Biomedicine of the University of Barcelona (IBUB) , University of Barcelona , Barcelona , Spain
| | - Mar Rodríguez-Ruiz
- a Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED) , Spain.,b Department of Biochemistry and Molecular Biomedicine, Faculty of Biology, Institute of Biomedicine of the University of Barcelona (IBUB) , University of Barcelona , Barcelona , Spain
| | - Enric I Canela
- a Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED) , Spain.,b Department of Biochemistry and Molecular Biomedicine, Faculty of Biology, Institute of Biomedicine of the University of Barcelona (IBUB) , University of Barcelona , Barcelona , Spain
| | - Vicent Casadó
- a Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED) , Spain.,b Department of Biochemistry and Molecular Biomedicine, Faculty of Biology, Institute of Biomedicine of the University of Barcelona (IBUB) , University of Barcelona , Barcelona , Spain
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Varshney R, Sethi SK, Rangaswamy S, Tiwari AK, Milton MD, Kumaran S, Mishra AK. Design, synthesis and relaxation studies of triazole linked gadolinium(iii)–DO3A-BT-bistriazaspirodecanone as a potential MRI contrast agent. NEW J CHEM 2016. [DOI: 10.1039/c5nj03220b] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Novel and facile synthesis of a triazole based bisconjugated triazaspirodecanone as a potential MRI contrast agent.
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Affiliation(s)
- Raunak Varshney
- Institute of Nuclear Medicine and Allied Sciences
- Delhi-54
- India
| | - Swarndeep K. Sethi
- Institute of Nuclear Medicine and Allied Sciences
- Delhi-54
- India
- Department of Chemistry
- University of Delhi
| | - Sandhya Rangaswamy
- Institute of Nuclear Medicine and Allied Sciences
- Delhi-54
- India
- Department of Chemistry
- University of Delhi
| | | | | | - Senthil Kumaran
- Department of NMR
- All India Institute of Medical Sciences
- New Delhi
- India
| | - Anil K. Mishra
- Institute of Nuclear Medicine and Allied Sciences
- Delhi-54
- India
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13
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Synthesis and evaluation of fluoro substituted pyridinylcarboxamides and their phenylazo analogues for potential dopamine D3 receptor PET imaging. Bioorg Med Chem Lett 2015; 24:5399-403. [PMID: 25453796 DOI: 10.1016/j.bmcl.2014.10.043] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2014] [Revised: 10/09/2014] [Accepted: 10/14/2014] [Indexed: 12/29/2022]
Abstract
A series of fluoro substituted pyridinylcarboxamides and their phenylazo analogues with high affinity and selectivity for the dopamine D3 receptor was synthesized by the use of 6-fluoropyridine-3-carbonyl chloride (1) and fluorophenylazocarboxylic ester (2). Several of these compounds (9a-e and 10a-h) have been evaluated in vitro, among which 9b, 10a, 10c and 10d proved to have at least single-digit nanomolar affinity for D3. They also exhibit considerable selectivity over the other dopamine receptor subtypes and noteworthy selectivity over the structurally related serotonin receptor subtypes 5-HT(1A) and 5-HT₂, offering potential radiotracers for positron emission tomography.
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Bartuschat AL, Schellhorn T, Hübner H, Gmeiner P, Heinrich MR. Fluoro-substituted phenylazocarboxamides: Dopaminergic behavior and N-arylating properties for irreversible binding. Bioorg Med Chem 2015; 23:3938-47. [DOI: 10.1016/j.bmc.2014.12.012] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2014] [Revised: 12/08/2014] [Accepted: 12/10/2014] [Indexed: 10/24/2022]
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15
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Kügler F, Ermert J, Kaufholz P, Coenen HH. 4-[18F]Fluorophenylpiperazines by improved Hartwig-Buchwald N-arylation of 4-[18F]fluoroiodobenzene, formed via hypervalent λ3-iodane precursors: application to build-up of the dopamine D4 ligand [18F]FAUC 316. Molecules 2014; 20:470-86. [PMID: 25558857 PMCID: PMC6272738 DOI: 10.3390/molecules20010470] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2014] [Accepted: 12/18/2014] [Indexed: 12/24/2022] Open
Abstract
Substituted phenylpiperazines are often neuropharmacologically active compounds and in many cases are essential pharmacophores of neuroligands for different receptors such as D2-like dopaminergic, serotoninergic and other receptors. Nucleophilic, no-carrier-added (n.c.a.) 18F-labelling of these ligands in an aromatic position is desirable for studying receptors with in vivo molecular imaging. 1-(4-[18F]Fluorophenyl)piperazine was synthesized in two reaction steps starting by 18F-labelling of a iodobenzene-iodonium precursor, followed by Pd-catalyzed N-arylation of the intermediate 4-[18F]fluoro-iodobenzene. Different palladium catalysts and solvents were tested with particular attention to the polar solvents dimethylformamide (DMF) and dimethylsulfoxide (DMSO). Weak inorganic bases like potassium phosphate or cesium carbonate seem to be essential for the arylation step and lead to conversation rates above 70% in DMF which is comparable to those in typically used toluene. In DMSO even quantitative conversation was observed. Overall radiochemical yields of up to 40% and 60% in DMF and DMSO, respectively, were reached depending on the labelling yield of the first step. The fluorophenylpiperazine obtained was coupled in a third reaction step with 2-formyl-1H-indole-5-carbonitrile to yield the highly selective dopamine D4 ligand [18F]FAUC 316.
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Affiliation(s)
- Fabian Kügler
- Institute of Neuroscience and Medicine, INM-5: Nuclear Chemistry, Forschungszentrum Jülich, 52425 Jülich, Germany.
| | - Johannes Ermert
- Institute of Neuroscience and Medicine, INM-5: Nuclear Chemistry, Forschungszentrum Jülich, 52425 Jülich, Germany.
| | - Peter Kaufholz
- Institute of Neuroscience and Medicine, INM-5: Nuclear Chemistry, Forschungszentrum Jülich, 52425 Jülich, Germany.
| | - Heinz H Coenen
- Institute of Neuroscience and Medicine, INM-5: Nuclear Chemistry, Forschungszentrum Jülich, 52425 Jülich, Germany.
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16
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Sethi SK, Varshney R, Rangaswamy S, Chadha N, Hazari PP, Kaul A, Chuttani K, Milton MD, Mishra AK. Design, synthesis and preliminary evaluation of a novel SPECT DTPA-bis-triazaspirodecanone conjugate for D2receptor imaging. RSC Adv 2014. [DOI: 10.1039/c4ra07004f] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
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17
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Liang SH, Yokell DL, Jackson RN, Rice PA, Callahan R, Johnson KA, Alagille D, Tamagnan G, Collier TL, Vasdev N. Microfluidic continuous-flow radiosynthesis of [ 18F]FPEB suitable for human PET imaging. MEDCHEMCOMM 2014; 5:432-435. [PMID: 25431646 DOI: 10.1039/c3md00335c] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
The synthesis of fluorine-18 labeled 3-fluoro-5-[(pyridin-3-yl)ethynyl] benzonitrile ([18F]FPEB) for imaging metabotropic glutamate receptor subtype type 5 (mGluR5) was achieved with a commercial continuous-flow microfluidics device. This work represents the first positron emission tomography (PET) radiopharmaceutical that is suitable for human use with this technology. We also describe a validated synthesis of [18F]FPEB with a commercial reactor-based system.
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Affiliation(s)
- Steven H Liang
- Department of Radiology, Harvard Medical School, 55 Fruit Street, Boston, MA, USA, 02114 ; Division of Nuclear Medicine and Molecular Imaging, Massachusetts General Hospital, 55 Fruit Street, Boston, MA, 02114
| | - Daniel L Yokell
- Division of Nuclear Medicine and Molecular Imaging, Massachusetts General Hospital, 55 Fruit Street, Boston, MA, 02114
| | - Raul N Jackson
- Division of Nuclear Medicine and Molecular Imaging, Massachusetts General Hospital, 55 Fruit Street, Boston, MA, 02114
| | - Peter A Rice
- Division of Nuclear Medicine and Molecular Imaging, Massachusetts General Hospital, 55 Fruit Street, Boston, MA, 02114
| | - Ronald Callahan
- Department of Radiology, Harvard Medical School, 55 Fruit Street, Boston, MA, USA, 02114 ; Division of Nuclear Medicine and Molecular Imaging, Massachusetts General Hospital, 55 Fruit Street, Boston, MA, 02114
| | - Keith A Johnson
- Department of Radiology, Harvard Medical School, 55 Fruit Street, Boston, MA, USA, 02114 ; Division of Nuclear Medicine and Molecular Imaging, Massachusetts General Hospital, 55 Fruit Street, Boston, MA, 02114
| | - David Alagille
- Molecular NeuroImaging, LLC, New Haven, CT, 06510 ; Institute for Neurodegenerative Disorders, New Haven, CT, 06510
| | - Gilles Tamagnan
- Molecular NeuroImaging, LLC, New Haven, CT, 06510 ; Institute for Neurodegenerative Disorders, New Haven, CT, 06510
| | - Thomas Lee Collier
- Department of Radiology, Harvard Medical School, 55 Fruit Street, Boston, MA, USA, 02114 ; Division of Nuclear Medicine and Molecular Imaging, Massachusetts General Hospital, 55 Fruit Street, Boston, MA, 02114 ; Advion Inc., 10 Brown Road, Ithaca, NY, 14850
| | - Neil Vasdev
- Department of Radiology, Harvard Medical School, 55 Fruit Street, Boston, MA, USA, 02114 ; Division of Nuclear Medicine and Molecular Imaging, Massachusetts General Hospital, 55 Fruit Street, Boston, MA, 02114
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18
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Hocke C, Cumming P, Maschauer S, Kuwert T, Gmeiner P, Prante O. Biodistribution studies of two 18F-labeled pyridinylphenyl amides as subtype selective radioligands for the dopamine D3 receptor. Nucl Med Biol 2013; 41:223-8. [PMID: 24480780 DOI: 10.1016/j.nucmedbio.2013.12.014] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2013] [Revised: 12/03/2013] [Accepted: 12/12/2013] [Indexed: 01/08/2023]
Abstract
INTRODUCTION Dopamine D3 receptors are implicated in various neuropsychiatric diseases, drug abuse and alcoholism, but specific agents for D3 molecular imaging are lacking. We evaluated two in vitro selective fluorine-18-labeled radioligand candidates ([(18)F]5 and [(18)F]6) for positron emission tomography (PET) imaging of D3 receptor availability in the brain. METHODS Biodistribution was evaluated in Sprague-Dawley rats using ex vivo autoradiography and small-animal PET. Protein binding studies were conducted in human plasma and cerebrospinal fluid. RESULTS [(18)F]5 showed rapid blood-brain barrier penetration and fast washout after intravenous injection, whereas the rat brain penetration of [(18)F]6 was lower. The total distribution volume (VT) of [(18)F]5 was 20-26 mL g(-1) throughout brain. Co-injection with the D3 antagonist BP897 resulted in globally increased cerebral washout of [(18)F]5 and [(18)F]6, but SUV analysis and parametric mapping of binding potential (BPND) relative to the cerebellum did not reveal specific binding of either ligand in D3-rich brain regions, i.e. the ventral striatum. However, there was substantial displaceable binding of [(18)F]5, and to a lesser extent [(18)F]6, in the pituitary. CONCLUSION These radioligands reveal dopamine D3 receptors in the pituitary, but are not suitable for PET imaging of in brain, possibly due to low specific signal relative to the globally high VT.
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Affiliation(s)
- Carsten Hocke
- Molecular Imaging and Radiochemistry, Nuclear Medicine Clinic, Friedrich-Alexander University, Schwabachanlage 6, D-91054 Erlangen, Germany.
| | - Paul Cumming
- Molecular Imaging and Radiochemistry, Nuclear Medicine Clinic, Friedrich-Alexander University, Schwabachanlage 6, D-91054 Erlangen, Germany
| | - Simone Maschauer
- Molecular Imaging and Radiochemistry, Nuclear Medicine Clinic, Friedrich-Alexander University, Schwabachanlage 6, D-91054 Erlangen, Germany
| | - Torsten Kuwert
- Molecular Imaging and Radiochemistry, Nuclear Medicine Clinic, Friedrich-Alexander University, Schwabachanlage 6, D-91054 Erlangen, Germany
| | - Peter Gmeiner
- Department of Chemistry and Pharmacy, Emil Fischer Center, Friedrich-Alexander University, Schuhstrasse 19, D-91052 Erlangen, Germany
| | - Olaf Prante
- Molecular Imaging and Radiochemistry, Nuclear Medicine Clinic, Friedrich-Alexander University, Schwabachanlage 6, D-91054 Erlangen, Germany
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19
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Fehler SK, Maschauer S, Höfling SB, Bartuschat AL, Tschammer N, Hübner H, Gmeiner P, Prante O, Heinrich MR. Fast and efficient (18) F-labeling by [(18) f]fluorophenylazocarboxylic esters. Chemistry 2013; 20:370-5. [PMID: 24339325 DOI: 10.1002/chem.201303409] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2013] [Indexed: 01/19/2023]
Abstract
Introduction of [(18) F]fluoride ion into the aromatic core of phenylazocarboxylic esters was achieved in only 30 seconds, with radiochemical yields of up to 95 % (85(±10) %). For labeling purposes, the resulting (18) F-substituted azoester can be further converted in radical-arylation reactions to give biaryls, or in substitutions at its carbonyl unit to produce azocarboxamides.
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Affiliation(s)
- Stefanie K Fehler
- Abteilung für Chemie und Pharmazie, Pharmazeutische Chemie, Friedrich-Alexander-Universität Erlangen-Nürnberg, Schuhstrasse 19, 91052 Erlangen (Germany)
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