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Beaurain M, Talmont F, Pierre D, Péran P, Boucher S, Hitzel A, Rols MP, Cuvillier O, Payoux P, Salabert AS. Pharmacological Characterization of [ 18F]-FNM and Evaluation of NMDA Receptors Activation in a Rat Brain Injury Model. Mol Imaging Biol 2023:10.1007/s11307-023-01811-y. [PMID: 36944798 DOI: 10.1007/s11307-023-01811-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2022] [Revised: 02/27/2023] [Accepted: 03/01/2023] [Indexed: 03/23/2023]
Abstract
PURPOSE NMDA receptors (NMDARs) dysfunction plays a central role in the physiopathology of psychiatric and neurodegenerative disorders whose mechanisms are still poorly understood. The development of a PET (positron emission tomography) tracer able to selectively bind to the NMDARs intra-channel PCP site may make it possible to visualize NMDARs in an open and active state. We describe the in vitro pharmacological characterization of [18F]-fluoroethylnormemantine ([18F]-FNM) and evaluate its ability to localize activated NMDA receptors in a rat preclinical model of excitotoxicity. PROCEDURES The affinity of the non-radioactive analog for the intra-channel PCP site was determined in a radioligand competition assay using [3H]TCP ([3H]N-(1-[thienyl]cyclohexyl)piperidine) on rat brain homogenates. Selectivity was also investigated by the displacement of specific radioligands targeting various cerebral receptors. In vivo brain lesions were performed using stereotaxic quinolinic acid (QA) injections in the left motor area (M1) of seven Sprague Dawley rats. Each rat was imaged with a microPET/CT camera, 40 min after receiving a dose of 30 MBq + / - 20 of [18F]-FNM, 24 and 72 h after injury. Nine non-injured rats were also imaged using the same protocol. RESULTS FNM displayed IC50 value of 13.0 ± 8.9 µM in rat forebrain homogenates but also showed significant bindings on opioid receptors. In the frontal and left somatosensory areas, [18F]FNM PET detected a mean of 37% and 41% increase in [18F]FNM uptake (p < 0,0001) 24 and 72 h after QA stereotaxic injection, respectively, compared to the control group. CONCLUSIONS In spite of FNM's poor affinity for NMDAR PCP site, this study supports the ability of this tracer to track massive activation of NMDARs in neurological diseases.
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Affiliation(s)
- Marie Beaurain
- Toulouse NeuroImaging Center, ToNIC, UMR1214 Inserm, Toulouse, France.
- Nuclear Medicine Department, Toulouse Purpan University Hospital, Toulouse, France.
| | - Franck Talmont
- Institut de Pharmacologie Et de Biologie Structurale, Université de Toulouse, CNRS, UPS, 31059, Toulouse, France
| | - Damien Pierre
- Toulouse NeuroImaging Center, ToNIC, UMR1214 Inserm, Toulouse, France
| | - Patrice Péran
- Toulouse NeuroImaging Center, ToNIC, UMR1214 Inserm, Toulouse, France
| | - Samuel Boucher
- Toulouse NeuroImaging Center, ToNIC, UMR1214 Inserm, Toulouse, France
| | - Anne Hitzel
- Nuclear Medicine Department, Toulouse Purpan University Hospital, Toulouse, France
| | - Marie-Pierre Rols
- Institut de Pharmacologie Et de Biologie Structurale, Université de Toulouse, CNRS, UPS, 31059, Toulouse, France
| | - Olivier Cuvillier
- Institut de Pharmacologie Et de Biologie Structurale, Université de Toulouse, CNRS, UPS, 31059, Toulouse, France
| | - Pierre Payoux
- Toulouse NeuroImaging Center, ToNIC, UMR1214 Inserm, Toulouse, France
- Nuclear Medicine Department, Toulouse Purpan University Hospital, Toulouse, France
| | - Anne-Sophie Salabert
- Toulouse NeuroImaging Center, ToNIC, UMR1214 Inserm, Toulouse, France
- Nuclear Medicine Department, Toulouse Purpan University Hospital, Toulouse, France
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Impact of the molar activity and PSMA expression level on [ 18F]AlF-PSMA-11 uptake in prostate cancer. Sci Rep 2021; 11:22623. [PMID: 34799653 PMCID: PMC8604919 DOI: 10.1038/s41598-021-02104-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2021] [Accepted: 11/10/2021] [Indexed: 11/10/2022] Open
Abstract
This two-part preclinical study aims to evaluate prostate specific membrane antigen (PSMA) as a valuable target for expression-based imaging applications and to determine changes in target binding in function of varying apparent molar activities (MAapp) of [18F]AlF-PSMA-11. For the evaluation of PSMA expression levels, male NOD/SCID mice bearing prostate cancer (PCa) xenografts of C4-2 (PSMA+++), 22Rv1 (PSMA+) and PC-3 (PSMA−) were administered [18F]AlF-PSMA-11 with a medium MAapp (20.24 ± 3.22 MBq/nmol). SUVmean and SUVmax values were respectively 3.22 and 3.17 times higher for the high versus low PSMA expressing tumors (p < 0.0001). To evaluate the effect of varying MAapp, C4-2 and 22Rv1 xenograft bearing mice underwent additional [18F]AlF-PSMA-11 imaging with a high (211.2 ± 38.9 MBq/nmol) and/or low MAapp (1.92 ± 0.27 MBq/nmol). SUV values showed a significantly increasing trend with higher MAapp. Significant changes were found for SUVmean and SUVmax between the high versus low MAapp and medium versus low MAapp (both p < 0.05), but not between the high versus medium MAapp (p = 0.055 and 0.25, respectively). The effect of varying MAapp was more pronounced in low expressing tumors and PSMA expressing tissues (e.g. salivary glands and kidneys). Overall, administration of a high MAapp increases the detection of low expression tumors while also increasing uptake in PSMA expressing tissues, possibly leading to false positive findings. In radioligand therapy, a medium MAapp could reduce radiation exposure to dose-limiting organs with only limited effect on radionuclide accumulation in the tumor.
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Abstract
Positron emission tomography (PET) is a non-invasive imaging technology employed to describe metabolic, physiological, and biochemical processes in vivo. These include receptor availability, metabolic changes, neurotransmitter release, and alterations of gene expression in the brain. Since the introduction of dedicated small-animal PET systems along with the development of many novel PET imaging probes, the number of PET studies using rats and mice in basic biomedical research tremendously increased over the last decade. This article reviews challenges and advances of quantitative rodent brain imaging to make the readers aware of its physical limitations, as well as to inspire them for its potential applications in preclinical research. In the first section, we briefly discuss the limitations of small-animal PET systems in terms of spatial resolution and sensitivity and point to possible improvements in detector development. In addition, different acquisition and post-processing methods used in rodent PET studies are summarized. We further discuss factors influencing the test-retest variability in small-animal PET studies, e.g., different receptor quantification methodologies which have been mainly translated from human to rodent receptor studies to determine the binding potential and changes of receptor availability and radioligand affinity. We further review different kinetic modeling approaches to obtain quantitative binding data in rodents and PET studies focusing on the quantification of endogenous neurotransmitter release using pharmacological interventions. While several studies have focused on the dopamine system due to the availability of several PET tracers which are sensitive to dopamine release, other neurotransmitter systems have become more and more into focus and are described in this review, as well. We further provide an overview of latest genome engineering technologies, including the CRISPR/Cas9 and DREADD systems that may advance our understanding of brain disorders and function and how imaging has been successfully applied to animal models of human brain disorders. Finally, we review the strengths and opportunities of simultaneous PET/magnetic resonance imaging systems to study drug-receptor interactions and challenges for the translation of PET results from bench to bedside.
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Hill JR, Shao X, Massey NL, Stauff J, Sherman PS, Robertson AAB, Scott PJH. Synthesis and evaluation of NLRP3-inhibitory sulfonylurea [ 11C]MCC950 in healthy animals. Bioorg Med Chem Lett 2020; 30:127186. [PMID: 32312583 DOI: 10.1016/j.bmcl.2020.127186] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2020] [Revised: 04/08/2020] [Accepted: 04/09/2020] [Indexed: 01/08/2023]
Abstract
The diaryl sulfonylurea MCC950/CRID3 is a potent NLRP3 inhibitor (IC50 = 8 nM) and, in animal models, MCC950 protects against numerous NLRP3-related neurodegenerative disorders. To evaluate the brain uptake and investigate target engagement of MCC950, we synthesised [11C-urea]MCC950 via carrier added [11C]CO2 fixation chemistry (activity yield = 237 MBq; radiochemical purity >99%; molar activity = 7 GBq/µmol; radiochemical yield (decay-corrected from [11C]CO2) = 1.1%; synthesis time from end-of-bombardment = 31 min; radiochemically stable for >1 h). Despite preclinical efficacy in neurodegeneration studies, preclinical positron emission tomography (PET) imaging studies in mouse, rat and rhesus monkey revealed poor brain uptake of low molar activity [11C]MCC950 and rapid washout. In silico prediction tools suggest efflux transporter liabilities for MCC950 at microdoses, and this information should be taken into account when developing next generation NLRP3 inhibitors and/or PET radiotracers.
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Affiliation(s)
- James R Hill
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland 4072, Australia; Department of Radiology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Xia Shao
- Department of Radiology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Nicholas L Massey
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland 4072, Australia
| | - Jenelle Stauff
- Department of Radiology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Phillip S Sherman
- Department of Radiology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Avril A B Robertson
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland 4072, Australia; School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, Queensland 4072, Australia.
| | - Peter J H Scott
- Department of Radiology, University of Michigan, Ann Arbor, MI 48109, USA.
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Brooks A, Drake LR, Shao X, Zhao A, Scott PJH, Kilbourn MR. Evaluation of Enzyme Substrate Radiotracers as PET/MRS Hybrid Imaging Agents. ACS Med Chem Lett 2018; 9:1140-1143. [PMID: 30429959 PMCID: PMC6231179 DOI: 10.1021/acsmedchemlett.8b00402] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2018] [Accepted: 10/03/2018] [Indexed: 01/23/2023] Open
Abstract
The development of a positron emission tomography (PET)/magnetic resonance spectroscopy (MRS) hybrid imaging agent allows for functional imaging by both methods with a single imaging agent. Enzyme substrates that are cleaved to form two metabolites present an interesting opportunity, as the unique metabolites generated might each be detected by a different modality. To be successful, such enzyme substrates would require administration of doses that (a) reach the in vivo target tissue at concentrations necessary for MRS imaging, (b) do not show substrate inhibition of tissue uptake or enzymatic activity, and (c) provide PET images that still reflect the action of the enzyme. We report in vitro and in vivo proof-of-concept studies of a carbon-11 small molecule substrate for brain monoamine oxidases that, upon enzyme-mediated cleavage, produces two metabolites, one detectable by PET and the other by MRS.
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Affiliation(s)
- Allen
F. Brooks
- Department
of Radiology, University of Michigan Medical
School, 1301 Catherine
Street, Ann Arbor, Michigan 48109, United States
| | - Lindsey R. Drake
- Department
of Medicinal Chemistry, University of Michigan, 930 North University Avenue, Ann Arbor, Michigan 48109, United States
| | - Xia Shao
- Department
of Radiology, University of Michigan Medical
School, 1301 Catherine
Street, Ann Arbor, Michigan 48109, United States
| | - Austin Zhao
- Department
of Radiology, University of Michigan Medical
School, 1301 Catherine
Street, Ann Arbor, Michigan 48109, United States
| | - Peter J. H. Scott
- Department
of Radiology, University of Michigan Medical
School, 1301 Catherine
Street, Ann Arbor, Michigan 48109, United States
- Department
of Medicinal Chemistry, University of Michigan, 930 North University Avenue, Ann Arbor, Michigan 48109, United States
| | - Michael R. Kilbourn
- Department
of Radiology, University of Michigan Medical
School, 1301 Catherine
Street, Ann Arbor, Michigan 48109, United States
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Kawamura K, Shimoda Y, Yui J, Zhang Y, Yamasaki T, Wakizaka H, Hatori A, Xie L, Kumata K, Fujinaga M, Ogawa M, Kurihara Y, Nengaki N, Zhang MR. A useful PET probe [ 11C]BU99008 with ultra-high specific radioactivity for small animal PET imaging of I 2-imidazoline receptors in the hypothalamus. Nucl Med Biol 2016; 45:1-7. [PMID: 27835825 DOI: 10.1016/j.nucmedbio.2016.10.005] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2016] [Revised: 10/14/2016] [Accepted: 10/24/2016] [Indexed: 01/23/2023]
Abstract
INTRODUCTION A positron emission tomography (PET) probe with ultra-high specific radioactivity (SA) enables measuring high receptor specific binding in brain regions by avoiding mass effect of the PET probe itself. It has been reported that PET probe with ultra-high SA can detect small change caused by endogenous or exogenous ligand. Recently, Kealey et al. developed [11C]BU99008, a more potent PET probe for I2-imidazoline receptors (I2Rs) imaging, with a conventional SA (mean 76GBq/μmol) showed higher specific binding in the brain. Here, to detect small change of specific binding for I2Rs caused by endogenous or exogenous ligand in an extremely small region, such as hypothalamus in the brain, we synthesized and evaluated [11C]BU99008 with ultra-high SA as a useful PET probe for small-animal PET imaging of I2Rs. METHODS [11C]BU99008 was prepared by [11C]methylation of N-desmethyl precursor with [11C]methyl iodide. Biodistribution, metabolite analysis, and brain PET studies were conducted in rats. RESULTS [11C]BU99008 with ultra-high SA in the range of 5400-16,600GBq/μmol were successfully synthesized (n=7), and had appropriate radioactivity for in vivo study. In the biodistribution study, the mean radioactivity levels in all investigated tissues except for the kidney did not show significant difference between [11C]BU99008 with ultra-high SA and that with conventional SA. In the metabolite analysis, the percentage of unchanged [11C]BU99008 at 30min after the injection of probes with ultra-high and conventional SA was similar in rat brain and plasma. In the PET study of rats' brain, radioactivity level (AUC30-60 min) in the hypothalamus of rats injected with [11C]BU99008 with ultra-high SA (64 [SUV ∙ min]) was significantly higher than that observed for that with conventional SA (50 [SUV ∙ min]). The specific binding of [11C]BU99008 with ultra-high SA (86% of total binding) for I2R was higher than that of conventional SA (76% of total binding). CONCLUSION A PET study using [11C]BU99008 with ultra-high SA would thus contribute to the detection of small changes in or small regions with I2R expression and hence may be useful in elucidating new functions of I2R.
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Affiliation(s)
- Kazunori Kawamura
- Department of Radiopharmaceuticals Development, National Institute of Radiological Sciences, National Institutes for Quantum and Radiological Science and Technology, Chiba 263-8555, Japan.
| | - Yoko Shimoda
- Department of Radiopharmaceuticals Development, National Institute of Radiological Sciences, National Institutes for Quantum and Radiological Science and Technology, Chiba 263-8555, Japan
| | - Joji Yui
- Department of Radiopharmaceuticals Development, National Institute of Radiological Sciences, National Institutes for Quantum and Radiological Science and Technology, Chiba 263-8555, Japan
| | - Yiding Zhang
- Department of Radiopharmaceuticals Development, National Institute of Radiological Sciences, National Institutes for Quantum and Radiological Science and Technology, Chiba 263-8555, Japan
| | - Tomoteru Yamasaki
- Department of Radiopharmaceuticals Development, National Institute of Radiological Sciences, National Institutes for Quantum and Radiological Science and Technology, Chiba 263-8555, Japan
| | - Hidekatsu Wakizaka
- Department of Medical Physics, National Institute of Radiological Sciences, National Institutes for Quantum and Radiological Science and Technology, Chiba 263-8555, Japan
| | - Akiko Hatori
- Department of Radiopharmaceuticals Development, National Institute of Radiological Sciences, National Institutes for Quantum and Radiological Science and Technology, Chiba 263-8555, Japan
| | - Lin Xie
- Department of Radiopharmaceuticals Development, National Institute of Radiological Sciences, National Institutes for Quantum and Radiological Science and Technology, Chiba 263-8555, Japan
| | - Katsushi Kumata
- Department of Radiopharmaceuticals Development, National Institute of Radiological Sciences, National Institutes for Quantum and Radiological Science and Technology, Chiba 263-8555, Japan
| | - Masayuki Fujinaga
- Department of Radiopharmaceuticals Development, National Institute of Radiological Sciences, National Institutes for Quantum and Radiological Science and Technology, Chiba 263-8555, Japan
| | - Masanao Ogawa
- Department of Radiopharmaceuticals Development, National Institute of Radiological Sciences, National Institutes for Quantum and Radiological Science and Technology, Chiba 263-8555, Japan; SHI Accelerator Service Ltd., Tokyo 141-0032, Japan
| | - Yusuke Kurihara
- Department of Radiopharmaceuticals Development, National Institute of Radiological Sciences, National Institutes for Quantum and Radiological Science and Technology, Chiba 263-8555, Japan; SHI Accelerator Service Ltd., Tokyo 141-0032, Japan
| | - Nobuki Nengaki
- Department of Radiopharmaceuticals Development, National Institute of Radiological Sciences, National Institutes for Quantum and Radiological Science and Technology, Chiba 263-8555, Japan; SHI Accelerator Service Ltd., Tokyo 141-0032, Japan
| | - Ming-Rong Zhang
- Department of Radiopharmaceuticals Development, National Institute of Radiological Sciences, National Institutes for Quantum and Radiological Science and Technology, Chiba 263-8555, Japan
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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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Yamasaki T, Fujinaga M, Yui J, Wakizaka H, Ohya T, Nengaki N, Ogawa M, Ikoma Y, Hatori A, Xie L, Kawamura K, Zhang MR. Improved Visualization and Specific Binding for Metabotropic Glutamate Receptor Subtype 1 (mGluR1) Using [11C]ITMM with Ultra-High Specific Activity in Small-Animal PET. PLoS One 2015; 10:e0130006. [PMID: 26076143 PMCID: PMC4468202 DOI: 10.1371/journal.pone.0130006] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2015] [Accepted: 04/29/2015] [Indexed: 12/15/2022] Open
Abstract
Metabotropic glutamate receptor subtype 1 (mGluR1) is a crucial target in the development of new medications to treat central nervous system (CNS) disorders. Recently, we developed N-[4-[6-(isopropylamino)pyrimidin-4-yl]-1,3-thiazol-2-yl]-4-[11C]methoxy-N-methyl-benzamide ([11C]ITMM) as a useful positron emission tomography (PET) probe for mGluR1 in clinical studies. Here, we aimed to improve visualization and threshold of specific binding for mGluR1 using [11C]ITMM with ultra-high specific activity (SA) of > 3,500 GBq/μmol in rat brains. A two-tissue compartment model indicated large differences between the two SAs in the constants k3 and k4, representing binding ability for mGluR1, while constants K1 and k2 showed no differences. The total distribution volume (VT) values of conventional and ultra-high SA were 9.1 and 11.2 in the thalamus, 7.7 and 9.7 in the striatum, and 6.4 and 8.5 mL/cm3 in the substantia nigra, respectively. The specific binding of [11C]ITMM with ultra-high SA was significantly higher than the conventional SA, especially in the basal ganglia. Parametric PET images scaled with VT of the ultra-high SA clearly identified regional differences in the rat brain. In conclusion, PET studies using [11C]ITMM with ultra-high SA could sufficiently improve visualization and specific binding for mGluR1, which could help further understanding for mGluR1 functions in CNS disorders.
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Affiliation(s)
- Tomoteru Yamasaki
- Molucular Probe Program, Molecular Imaging Center, National Institute of Radiological Sciences, Chiba, Japan
- * E-mail:
| | - Masayuki Fujinaga
- Molucular Probe Program, Molecular Imaging Center, National Institute of Radiological Sciences, Chiba, Japan
| | - Joji Yui
- Molucular Probe Program, Molecular Imaging Center, National Institute of Radiological Sciences, Chiba, Japan
| | - Hidekatsu Wakizaka
- Molucular Probe Program, Molecular Imaging Center, National Institute of Radiological Sciences, Chiba, Japan
| | - Tomoyuki Ohya
- Molucular Probe Program, Molecular Imaging Center, National Institute of Radiological Sciences, Chiba, Japan
| | - Nobuki Nengaki
- Molucular Probe Program, Molecular Imaging Center, National Institute of Radiological Sciences, Chiba, Japan
| | - Masanao Ogawa
- Molucular Probe Program, Molecular Imaging Center, National Institute of Radiological Sciences, Chiba, Japan
| | - Yoko Ikoma
- Molucular Probe Program, Molecular Imaging Center, National Institute of Radiological Sciences, Chiba, Japan
| | - Akiko Hatori
- Molucular Probe Program, Molecular Imaging Center, National Institute of Radiological Sciences, Chiba, Japan
| | - Lin Xie
- Molucular Probe Program, Molecular Imaging Center, National Institute of Radiological Sciences, Chiba, Japan
| | - Kazunori Kawamura
- Molucular Probe Program, Molecular Imaging Center, National Institute of Radiological Sciences, Chiba, Japan
| | - Ming-Rong Zhang
- Molucular Probe Program, Molecular Imaging Center, National Institute of Radiological Sciences, Chiba, Japan
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Prante O, Maschauer S, Banerjee A. Radioligands for the dopamine receptor subtypes. J Labelled Comp Radiopharm 2014; 56:130-48. [PMID: 24285319 DOI: 10.1002/jlcr.3000] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2012] [Revised: 10/11/2012] [Accepted: 11/06/2012] [Indexed: 12/29/2022]
Abstract
The actions of the predominant neurotransmitter in the brain, dopamine, are mediated by the postsynaptic dopamine receptors. The five dopamine receptor subtypes and their regulation have been associated with a large variety of psychiatric diseases. Therefore, positron emission tomography (PET) imaging studies using suitable and selective (18) F-labeled and (11) C-labeled dopamine receptor radioligands could provide valuable knowledge on the impact of receptor density on the pathogenesis and evolvement of neuropsychiatric and neurological diseases. This special issue subchapter provides a summary of the most important (18) F-labeled and (11) C-labeled radioligands for PET imaging of the dopamine receptor subtypes, their radiochemistry, and characteristics from in vitro and in vivo applications, considering not only the already established PET ligands but also the recently published preclinical work.
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Affiliation(s)
- Olaf Prante
- Laboratory of Molecular Imaging and Radiochemistry, Friedrich-Alexander University, Schwabachanlage 6, D-91054, Erlangen, Germany
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Yamasaki T, Kumata K, Yui J, Fujinaga M, Furutsuka K, Hatori A, Xie L, Ogawa M, Nengaki N, Kawamura K, Zhang MR. Synthesis and evaluation of [11C]MMPIP as a potential radioligand for imaging of metabotropic glutamate 7 receptor in the brain. EJNMMI Res 2013; 3:54. [PMID: 23870677 PMCID: PMC3751550 DOI: 10.1186/2191-219x-3-54] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2013] [Accepted: 07/11/2013] [Indexed: 12/28/2022] Open
Abstract
BACKGROUND Metabotropic glutamate 7 (mGlu7) receptor is a crucial target protein for the development of pharmaceuticals against central nervous system disorders. In the present study, we synthesized [11C]MMPIP, a putative radioligand for mGlu7 (binding constant KB = 30 nM), and evaluated its potential for imaging of mGlu7 via in vitro and in vivo techniques. METHODS [11C]MMPIP was synthesized by the reaction of phenol precursor 3 with [11C]CH3I. In vitro autoradiography using [11C]MMPIP was performed on rat brain sections. To determine in vitro specific binding of [11C]MMPIP with mGlu7, a blocking study was conducted by co-incubation with excess AMN082, a selective antagonist for mGlu7, or unlabeled MMPIP. Positron emission tomography (PET) studies and ex vivo metabolite analysis were carried out on rat brains. RESULTS [11C]MMPIP was obtained with two specific activity (SA) levels of average 58 (conventional) and 3,800 (high SA) GBq/μmol, respectively. High radioactive signals derived from conventional [11C]MMPIP in the in vitro autoradiography were seen in the thalamus, medulla oblongata, and striatum, corresponding with comprehensive brain distributions of mGlu7. Co-incubation with ANM082 or unlabeled MMPIP reduced the radioactive signals in the brain sections, respectively. In the PET studies with [11C]MMPIP, no specific uptake relative to mGlu7 was found in the examined brain regions. CONCLUSION Despite in vitro specific binding of [11C]MMPIP with mGlu7, visualization of mGlu7 in the living brain using PET was not successful. Development of new ligand candidates with higher affinity for mGlu7 is necessary.
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Affiliation(s)
- Tomoteru Yamasaki
- Molecular Probe Program, Molecular Imaging Center, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba 263-8555, Japan.
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Lettfuss NY, Fischer K, Sossi V, Pichler BJ, von Ameln-Mayerhofer A. Imaging DA release in a rat model of L-DOPA-induced dyskinesias: A longitudinal in vivo PET investigation of the antidyskinetic effect of MDMA. Neuroimage 2012; 63:423-33. [DOI: 10.1016/j.neuroimage.2012.06.051] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2012] [Revised: 06/03/2012] [Accepted: 06/26/2012] [Indexed: 01/04/2023] Open
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Fujinaga M, Yamasaki T, Yui J, Hatori A, Xie L, Kawamura K, Asagawa C, Kumata K, Yoshida Y, Ogawa M, Nengaki N, Fukumura T, Zhang MR. Synthesis and evaluation of novel radioligands for positron emission tomography imaging of metabotropic glutamate receptor subtype 1 (mGluR1) in rodent brain. J Med Chem 2012; 55:2342-52. [PMID: 22316010 DOI: 10.1021/jm201590g] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We designed three novel positron emission tomography ligands, N-(4-(6-(isopropylamino)pyrimidin-4-yl)-1,3-thiazol-2-yl)-4-[(11)C]methoxy-N-methylbenzamide ([(11)C]6), 4-[(18)F]fluoroethoxy-N-[4-[6-(isopropylamino)pyrimidin-4-yl]-1,3-thiazol-2-yl]-N-methylbenzamide ([(18)F]7), and 4-[(18)F]fluoropropoxy-N-[4-[6-(isopropylamino)pyrimidin-4-yl]-1,3-thiazol-2-yl]-N-methylbenzamide ([(18)F]8), for imaging metabotropic glutamate receptor type 1 (mGluR1) in rodent brain. Unlabeled compound 6 was synthesized by benzoylation of 4-pyrimidinyl-2-methylaminothiazole 10, followed by reaction with isopropylamine. Removal of the methyl group in 6 gave phenol precursor 12 for radiosynthesis. Two fluoroalkoxy analogues 7 and 8 were prepared by reacting 12 with tosylates 13 and 14. Radioligands [(11)C]6, [(18)F]7, and [(18)F]8 were synthesized by O-[(11)C]methylation or [(18)F]fluoroalkylation of 12. Compound 6 showed high in vitro binding affinity for mGluR1, whereas 7 and 8 had weak affinity. Autoradiography using rat brain sections showed that [(11)C]6 binding is aligned with the reported distribution of mGluR1 with high specific binding in the cerebellum and thalamus. PET study with [(11)C]6 in rats showed high brain uptake and a similar distribution pattern to that in autoradiography, indicating the usefulness of [(11)C]6 for imaging brain mGluR1.
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Affiliation(s)
- Masayuki Fujinaga
- Molecular Imaging Center, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba 263-8555, Japan
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Kawamura K, Kimura Y, Yui J, Wakizaka H, Yamasaki T, Hatori A, Kumata K, Fujinaga M, Yoshida Y, Ogawa M, Nengaki N, Fukumura T, Zhang MR. PET study using [11C]FTIMD with ultra-high specific activity to evaluate I2-imidazoline receptors binding in rat brains. Nucl Med Biol 2012; 39:199-206. [DOI: 10.1016/j.nucmedbio.2011.07.008] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2011] [Revised: 06/29/2011] [Accepted: 07/26/2011] [Indexed: 10/17/2022]
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14
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Fischer K, Sossi V, Schmid A, Thunemann M, Maier FC, Judenhofer MS, Mannheim JG, Reischl G, Pichler BJ. Noninvasive Nuclear Imaging Enables the In Vivo Quantification of Striatal Dopamine Receptor Expression and Raclopride Affinity in Mice. J Nucl Med 2011; 52:1133-41. [DOI: 10.2967/jnumed.110.086942] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
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Measurement of dopamine D2 receptors in living human brain using [11C]raclopride with ultra-high specific radioactivity. Nucl Med Biol 2010; 37:831-5. [DOI: 10.1016/j.nucmedbio.2010.04.138] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2010] [Accepted: 04/16/2010] [Indexed: 10/19/2022]
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16
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Yui J, Hatori A, Kawamura K, Yanamoto K, Yamasaki T, Ogawa M, Yoshida Y, Kumata K, Fujinaga M, Nengaki N, Fukumura T, Suzuki K, Zhang MR. Visualization of early infarction in rat brain after ischemia using a translocator protein (18 kDa) PET ligand [11C]DAC with ultra-high specific activity. Neuroimage 2010; 54:123-30. [PMID: 20705143 DOI: 10.1016/j.neuroimage.2010.08.010] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2010] [Revised: 07/23/2010] [Accepted: 08/04/2010] [Indexed: 10/19/2022] Open
Abstract
The aim of this study was to visualize early infarction in the rat brain after ischemia using a translocator protein (TSPO) (18 kDa) PET ligand [(11)C]DAC with ultra-high specific activity (SA) of 3670-4450 GBq/μmol. An infarction model of rat brain was prepared by ischemic surgery and evaluated 2 days after ischemia using small-animal PET and in vitro autoradiography. Early infarction with a small increase of TSPO expression in the brain was visualized using PET with high SA [(11)C]DAC (average 4060 GBq/μmol), but was not distinguished clearly with usually reported SA [(11)C]DAC (37 GBq/μmol). Infarction in the rat brain 4 days after ischemia was visualized using high and usually reported SAs [(11)C]DAC. Displacement experiments with unlabeled TSPO-selective AC-5216 or PK11195 diminished the difference in radioactivity between ipsilateral and contralateral sides, confirming that the increased uptake on the infracted brain was specific to TSPO. In vitro autoradiography with high SA [(11)C]DAC showed that the TSPO expression increased on early infarction in the rat brain. High SA [(11)C]DAC is a useful and sensitive biomarker for the visualization of early infarction and the characterization of TSPO expression which was slightly elevated in the infarcted brain using PET.
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Affiliation(s)
- Joji Yui
- Molecular Imaging Center, National Institute of Radiological Sciences, Inage-ku, Chiba, Japan
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Yui J, Hatori A, Yanamoto K, Takei M, Nengaki N, Kumata K, Kawamura K, Yamasaki T, Suzuki K, Zhang MR. Imaging of the translocator protein (18kDa) in rat brain after ischemia using [11C]DAC with ultra-high specific activity. Synapse 2010; 64:488-93. [DOI: 10.1002/syn.20761] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Kumata K, Takei M, Ogawa M, Kato K, Suzuki K, Zhang MR. One-pot radiosynthesis of [13N]urea and [13N]carbamate using no-carrier-added [13N]NH3. J Labelled Comp Radiopharm 2009. [DOI: 10.1002/jlcr.1584] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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In-target produced [11C]methane: Increased specific radioactivity. Appl Radiat Isot 2009; 67:106-10. [DOI: 10.1016/j.apradiso.2008.09.010] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2008] [Revised: 09/18/2008] [Accepted: 09/19/2008] [Indexed: 11/22/2022]
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20
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Nakao R, Furutsuka K, Fukumura T, Yamaguchi M, Suzuki K. Quality control of PET radiopharmaceuticals by high-performance liquid chromatography with tris(2,2′-bipyridyl)ruthenium(II) electrogenerated chemiluminescence detection. Biomed Chromatogr 2009; 24:202-8. [DOI: 10.1002/bmc.1274] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Zhang MR, Kumata K, Takei M, Fukumura T, Suzuki K. How to introduce radioactive chlorine into a benzene ring using [*Cl]Cl-? Appl Radiat Isot 2008; 66:1341-5. [PMID: 18508276 DOI: 10.1016/j.apradiso.2008.04.011] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2007] [Accepted: 04/14/2008] [Indexed: 11/16/2022]
Abstract
The aim of this study was how to introduce radioactive chlorine (*Cl) isotope into a benzene ring to afford *Cl-labeled chlorobenzene ([*Cl]1). Using tributylphenylstannyl compound (2) as a starting material, we determined two routes for introducing *Cl into the benzene ring: reaction of [*Cl]Cl(-) with 2 in the presence of chloramine-T and nucleophilic reaction of [*Cl]Cl(-) with diphenyliodonium tosylate (3). The two routes provide suitable tools to prepare [*Cl]1 without electron-abstracting group in the benzene ring.
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Affiliation(s)
- Ming-Rong Zhang
- Department of Molecular Probes, Molecular Imaging Center, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba 263-8555, Japan.
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