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Saednia S, Emami S, Moslehi M, Hosseinimehr SJ. Insights into the development of 99mTc-radioligands for serotonergic receptors imaging: Synthesis, labeling, In vitro, and In vivo studies. Eur J Med Chem 2024; 270:116349. [PMID: 38555856 DOI: 10.1016/j.ejmech.2024.116349] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2024] [Revised: 03/15/2024] [Accepted: 03/18/2024] [Indexed: 04/02/2024]
Abstract
Serotonergic (5-hydroxytryptamine; 5-HT) receptors play critical roles in neurological and psychological disorders such as schizophrenia, anxiety, depression, and Alzheimer's diseases. Therefore, it is particularly important to develop novel radioligands or modify the existing ones to identify the serotonergic receptors involved in psychiatric disorders. Among the 16 subtypes of serotonergic systems, only technetium-99m based radiopharmaceuticals have been evaluated for serotonin-1A (5-HT1A), serotonin-2A (5-HT2A), 5-HT1A/7 heterodimers and serotonin receptor neurotransmitter (SERT). This review focuses on recent efforts in the design, synthesis and evaluation of 99mTc-radioligands used for single photon emission computerized tomography (SPECT) imaging of serotonergic (5-HT) receptors. Additionally, the discussion will cover aspects such as chemical structure, in vitro/vivo stability, affinity toward serotonin receptors, blood-brain barrier permeation (BBB), and biodistribution study.
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Affiliation(s)
- Shahnaz Saednia
- Farabi Hospital, Isfahan University of Medical Sciences, Isfahan, Iran; Department of Radiopharmacy, Faculty of Pharmacy, Mazandaran University of Medical Sciences, Sari, Iran
| | - Saeed Emami
- Department of Medicinal Chemistry and Pharmaceutical Sciences Research Center, Faculty of Pharmacy, Mazandaran University of Medical Sciences, Sari, Iran
| | - Masoud Moslehi
- Department of Medical Physics, School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran
| | - Seyed Jalal Hosseinimehr
- Department of Radiopharmacy, Faculty of Pharmacy, Mazandaran University of Medical Sciences, Sari, Iran.
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2
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Joshi PV, Sayed AA, RaviKumar A, Puranik VG, Zinjarde SS. 4-Phenyl quinoline derivatives as potential serotonin receptor ligands with antiproliferative activity. Eur J Med Chem 2017; 136:246-258. [DOI: 10.1016/j.ejmech.2017.05.002] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2016] [Revised: 04/16/2017] [Accepted: 05/01/2017] [Indexed: 02/03/2023]
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3
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Stehouwer JS, Goodman MM. Fluorine-18 Radiolabeled PET Tracers for Imaging Monoamine Transporters: Dopamine, Serotonin, and Norepinephrine. PET Clin 2016; 4:101-28. [PMID: 20216936 DOI: 10.1016/j.cpet.2009.05.006] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
This review focuses on the development of fluorine-18 radiolabeled PET tracers for imaging the dopamine transporter (DAT), serotonin transporter (SERT), and norepinephrine transporter (NET). All successful DAT PET tracers reported to date are members of the 3β-phenyl tropane class and are synthesized from cocaine. Currently available carbon-11 SERT PET tracers come from both the diphenylsulfide and 3β-phenyl nortropane class, but so far only the nortropanes have found success with fluorine-18 derivatives. NET imaging has so far employed carbon-11 and fluorine-18 derivatives of reboxetine but due to defluorination of the fluorine-18 derivatives further research is still necessary.
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4
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Kim J, Lee KH, Lee SJ, Lee HW, Kim YK, Kim YS, Yoon SS. Red Phosphorescent Bis-Cyclometalated Iridium Complexes with Fluorine-, Phenyl-, and Fluorophenyl-Substituted 2-Arylquinoline Ligands. Chemistry 2016; 22:4036-45. [DOI: 10.1002/chem.201504392] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2015] [Indexed: 11/10/2022]
Affiliation(s)
- Jwajin Kim
- Department of Chemistry; Sungkyunkwan University; 2066, Seobu-ro, Jangan-gu, Suwon-si Gyeonggi-do Korea
| | - Kum Hee Lee
- Department of Chemistry; Sungkyunkwan University; 2066, Seobu-ro, Jangan-gu, Suwon-si Gyeonggi-do Korea
| | - Seok Jae Lee
- Department of Information Display; Hongik University; 94, Wausan-ro, Mapo-gu Seoul Korea
| | - Ho Won Lee
- Department of Information Display; Hongik University; 94, Wausan-ro, Mapo-gu Seoul Korea
| | - Young Kwan Kim
- Department of Information Display; Hongik University; 94, Wausan-ro, Mapo-gu Seoul Korea
| | - Young Sik Kim
- Department of Information Display; Hongik University; 94, Wausan-ro, Mapo-gu Seoul Korea
| | - Seung Soo Yoon
- Department of Chemistry; Sungkyunkwan University; 2066, Seobu-ro, Jangan-gu, Suwon-si Gyeonggi-do Korea
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5
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Kim JY, Son MH, Choi K, Baek DJ, Ko MK, Lim EJ, Pae AN, Keum G, Lee JK, Cho YS, Choo H, Lee YW, Moon BS, Lee BC, Lee HY, Min SJ. Synthesis and In vivo Evaluation of 5-Methoxy-2-(phenylethynyl)quinoline (MPEQ) and [11C]MPEQ Targeting Metabotropic Glutamate Receptor 5 (mGluR5). B KOREAN CHEM SOC 2014. [DOI: 10.5012/bkcs.2014.35.8.2304] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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6
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Saggadi H, Luart D, Thiebault N, Polaert I, Estel L, Len C. Quinoline and phenanthroline preparation starting from glycerol via improved microwave-assisted modified Skraup reaction. RSC Adv 2014. [DOI: 10.1039/c4ra00758a] [Citation(s) in RCA: 54] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
An efficient “green” modified Skraup reaction in neat water was developed using inexpensive, abundant and environmentally-friendly glycerol under microwave irradiation conditions.
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Affiliation(s)
- Hanen Saggadi
- Transformations Intégrées de la Matière Renouvelable
- EA 4297
- UTC-ESCOM
- Centre de Recherche de Royallieu
- F-60200 Compiègne, France
| | - Denis Luart
- Transformations Intégrées de la Matière Renouvelable
- EA 4297
- UTC-ESCOM
- Centre de Recherche de Royallieu
- F-60200 Compiègne, France
| | - Nicolas Thiebault
- Transformations Intégrées de la Matière Renouvelable
- EA 4297
- UTC-ESCOM
- Centre de Recherche de Royallieu
- F-60200 Compiègne, France
| | - Isabelle Polaert
- Laboratoire de Sécurité des Procédés Chimiques – EA 4704 INSA Rouen
- Avenue de l'Université
- F-76801 Saint-Etienne-du-Rouvray Cedex, France
| | - Lionel Estel
- Laboratoire de Sécurité des Procédés Chimiques – EA 4704 INSA Rouen
- Avenue de l'Université
- F-76801 Saint-Etienne-du-Rouvray Cedex, France
| | - C. Len
- Transformations Intégrées de la Matière Renouvelable
- EA 4297
- UTC-ESCOM
- Centre de Recherche de Royallieu
- F-60200 Compiègne, France
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7
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Shmoilova EA, Dyablo OV, Pozharskii AF. Synthesis of 4,5-Bis(Dimethylamino)Quinolines and the Dual Direction of their Protonation. Chem Heterocycl Compd (N Y) 2013. [DOI: 10.1007/s10593-013-1380-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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8
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Jarkas N, Voll RJ, Goodman MM. Synthesis of a phenolic precursor and its efficientO-[18F]fluoroethylation with purified no-carrier-added [18F]2-fluoroethyl brosylate as the labeling agent. J Labelled Comp Radiopharm 2013; 56:539-43. [DOI: 10.1002/jlcr.3046] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2013] [Revised: 03/07/2013] [Accepted: 03/12/2013] [Indexed: 11/07/2022]
Affiliation(s)
- Nashwa Jarkas
- Department of Radiology and Imaging Sciences; Emory University School of Medicine, Center for Systems Imaging, Wesley Woods Health Center; Atlanta; GA; USA
| | - Ronald J. Voll
- Department of Radiology and Imaging Sciences; Emory University School of Medicine, Center for Systems Imaging, Wesley Woods Health Center; Atlanta; GA; USA
| | - Mark M. Goodman
- Department of Radiology and Imaging Sciences; Emory University School of Medicine, Center for Systems Imaging, Wesley Woods Health Center; Atlanta; GA; USA
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Gabrielsen M, Wołosewicz K, Zawadzka A, Kossakowski J, Nowak G, Wolak M, Stachowicz K, Siwek A, Ravna AW, Kufareva I, Kozerski L, Bednarek E, Sitkowski J, Bocian W, Abagyan R, Bojarski AJ, Sylte I, Chilmonczyk Z. Synthesis, antidepressant evaluation and docking studies of long-chain alkylnitroquipazines as serotonin transporter inhibitors. Chem Biol Drug Des 2013; 81:695-706. [PMID: 23574807 DOI: 10.1111/cbdd.12116] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2012] [Revised: 12/19/2012] [Accepted: 01/15/2013] [Indexed: 10/27/2022]
Abstract
Twelve alkyl analogues (1-12) of the high-affinity serotonin transporter (SERT) inhibitor 6-nitroquipazine (6-NQ) were synthesized and studied using in vitro radioligand competition binding assays to determine their binding affinity (Ki ). The putative antidepressant activity of five of the binders with the highest SERT binding affinities was studied by the forced swim and locomotor activity mouse tests. The three-dimensional (3D) structures of 8 and 9 were determined using NOE NMR technique. Flexible docking of the compounds was undertaken to illustrate the binding of the compounds in the SERT model. Our results showed that several of the 6-NQ analogues are high-affinity SERT inhibitors and indicated that the octyl (8), decyl (10) and dodecyl (12) 6-NQ analogues exhibit moderate antidepressant activity.
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Affiliation(s)
- Mari Gabrielsen
- Medical Pharmacology and Toxicology, Department of Medical Biology, Faculty of Health Sciences, University of Tromsø, 9037 Tromsø, Norway
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10
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Son MH, Kim JY, Lim EJ, Baek DJ, Choi K, Lee JK, Pae AN, Min SJ, Cho YS. Synthesis and biological evaluation of 2-(arylethynyl)quinoline derivatives as mGluR5 antagonists for the treatment of neuropathic pain. Bioorg Med Chem Lett 2013; 23:1472-6. [DOI: 10.1016/j.bmcl.2012.12.056] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2012] [Revised: 12/13/2012] [Accepted: 12/15/2012] [Indexed: 10/27/2022]
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11
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Zheng P, Lieberman BP, Ploessl K, Lemoine L, Miller S, Kung HF. A new single-photon emission computed tomography (SPECT) imaging agent for serotonin transporters: [(125)I]Flip-IDAM, (2-((2-((dimethylamino)methyl)-4-iodophenyl)thio)phenyl)methanol. Bioorg Med Chem Lett 2013; 23:869-72. [PMID: 23265880 DOI: 10.1016/j.bmcl.2012.11.043] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2012] [Revised: 11/07/2012] [Accepted: 11/12/2012] [Indexed: 11/18/2022]
Abstract
New ligands for in vivo brain imaging of serotonin transporter (SERT) with single photon emission tomography (SPECT) were prepared and evaluated. An efficient synthesis and radiolabeling of a biphenylthiol, FLIP-IDAM, 4, was accomplished. The affinity of FLIP-IDAM was evaluated by an in vitro inhibitory binding assay using [(125)I]-IDAM as radioligand in rat brain tissue homogenates (K(i) = 0.03 nM). New [(125)I]Flip-IDAM exhibited excellent binding affinity to SERT binding sites with a high hypothalamus to cerebellum ratio of 4 at 30 min post iv injection. The faster in vivo kinetics for brain uptake and a rapid washout from non-specific regions provide excellent signal to noise ratio. This new agent, when labeled with (123)I, may be a useful imaging agent for mapping SERT binding sites in the human brain.
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Affiliation(s)
- Pinguan Zheng
- Department of Radiology, University of Pennsylvania, Philadelphia, PA 19104, USA
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12
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Wang JL, Deutsch EC, Oya S, Kung HF. FlipADAM: a potential new SPECT imaging agent for the serotonin transporter. Nucl Med Biol 2010; 37:577-86. [DOI: 10.1016/j.nucmedbio.2010.02.010] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2009] [Revised: 02/09/2010] [Accepted: 02/27/2010] [Indexed: 10/19/2022]
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13
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Němcová L, Zima J, Barek J. Determination of 5-amino-6-nitroquinoline at a carbon paste electrode. ACTA ACUST UNITED AC 2009. [DOI: 10.1135/cccc2009065] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Differential pulse voltammetry, direct current voltammetry, adsorptive stripping voltammetry and HPLC with electrochemical detection were used for the determination of 5-amino-6-nitroquinoline at a carbon paste electrode. The methods are based either on anodic oxidation or cathodic reduction of this substance, whose electrochemical behavior at carbon paste electrode was further studied by cyclic voltammetry. Practical applicability of these methods was demonstrated on the determination of 5-amino-6-nitroquinoline in model samples of drinking and river water. The detection limit was 2.0 × 10–6 mol l–1 for anodic differential pulse voltammetry in a mixture of Britton–Robinson buffer (pH 11)–methanol 1:1 (v/v) and 1.6 × 10–7 mol l–1 for HPLC with electrochemical detection (E = +1.2 V) in a mobile phase Britton–Robinson buffer (pH 7)–methanol 1:9 (v/v).
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14
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Wang JL, Parhi AK, Oya S, Lieberman B, Kung HF. In Vivo Characterization of a Series of 18F-Diaryl Sulfides (18F-2-(2′-((Dimethylamino)Methyl)-4′-(Fluoroalkoxy)Phenylthio)Benzenamine) for PET Imaging of the Serotonin Transporter. J Nucl Med 2009; 50:1509-17. [DOI: 10.2967/jnumed.108.060723] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
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15
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Parhi AK, Wang JL, Oya S, Choi SR, Kung MP, Kung HF. 2-(2'-((dimethylamino)methyl)-4'-(fluoroalkoxy)-phenylthio)benzenamine derivatives as serotonin transporter imaging agents. J Med Chem 2007; 50:6673-84. [PMID: 18052090 DOI: 10.1021/jm070685e] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
A novel series of ligands with substitutions at the 5-position on phenyl ring A and at the 4'-position on phenyl ring B of 2-(2'-((dimethylamino)methyl)-4'-(fluoroalkoxy)phenylthio)benzenamine (4'-2-fluoroethoxy derivatives 28-31 and 4'-3-fluoropropoxy derivatives 40-42) were prepared and tested as serotonin transporter (SERT) imaging agents. The new ligands displayed high binding affinities to SERT (Ki ranging from 0.03 to 1.4 nM). The corresponding 18F labeled compounds, which can be prepared readily, showed excellent brain uptake and retention after iv injection in rats. The hypothalamus region showed high uptake values between 0.74% and 2.2% dose/g at 120 min after iv injection. Significantly, the hypothalamus to cerebellum ratios (target to nontarget ratios) at 120 min were 7.8 and 7.7 for [18F]28 and [18F]40, respectively. The selective uptake and retention in the hypothalamus, which has a high concentration of SERT binding sites, demonstrated that [18F]28 and [18F]40 are promising positron emission computed tomography imaging agents for mapping SERT binding sites in the brain.
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Affiliation(s)
- Ajit K Parhi
- Department of Radiology, University of Pennsylvania, Philadelphia 19104, USA
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16
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Stone-Elander S, Elander N, Thorell JO, Fredriksson A. Microwaving in F-18 chemistry: quirks and tweaks. ERNST SCHERING RESEARCH FOUNDATION WORKSHOP 2007:243-69. [PMID: 17172158 DOI: 10.1007/978-3-540-49527-7_9] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
Since the late 1980s, microwave dielectric heating has been used to speed up chemical transformations, also in radiolabeling tracers for positron emission tomography. In addition to shorter reaction times, higher yields, cleaner product mixtures and improved reproducibility have also been obtained for reactions involving polar components that require heating at elevated temperatures. The conditions used in microwave chemistry can differ considerably from those in conventional heating. Understanding the factors that influence the interaction of the electromagnetic field with the sample is critical for the successful implementation of microwave heating. These parameters are discussed here and exemplified with radiolabelings with fluorine-18.
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Affiliation(s)
- S Stone-Elander
- Department of Clinical Neuroscience, Positron Emission Tomography, Karolinska Pharmacy, Karolinska University Hospital, Stockholm, Sweden.
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17
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Roeda D, Kuhnast B, Hammadi A, Dollé F. The Service Hospitalier Frédéric Joliot – contributions to PET chemistry over the years. J Labelled Comp Radiopharm 2007. [DOI: 10.1002/jlcr.1420] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
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18
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Huang Y, Bae SA, Zhu Z, Guo N, Roth BL, Laruelle M. Fluorinated diaryl sulfides as serotonin transporter ligands: synthesis, structure-activity relationship study, and in vivo evaluation of fluorine-18-labeled compounds as PET imaging agents. J Med Chem 2005; 48:2559-70. [PMID: 15801845 DOI: 10.1021/jm0400808] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
A series of new, fluorine-containing substituted diphenyl sulfides was synthesized to serve as candidate ligands for positron emission tomography (PET) imaging of the serotonin transporter (SERT) and to further probe the structure-activity relationship (SAR) of this class of compounds. Candidate compounds were assayed for their affinities to the monoamine transporters (SERT, norepinephrine transporter (NET), and dopamine transporter (DAT)) in competitive binding experiments in vitro using cloned human transporters. From these in vitro assays, four compounds (7c-f) were chosen for further evaluation. All four compounds have nanomolar affinity for SERT (K(i) 1.46 nM, 1.04 nM,1.83 nM, and 3.58 nM for 7c, 7d, 7e, and 7f, respectively). The F-18-labeled compounds, 16 and 18a-c, were prepared via a two-step radiosynthesis. Biodistribution studies in rats indicated that the F-18-labeled compounds localized in brain regions with high concentrations of SERT. Furthermore, competition experiments demonstrated that the binding of these radioligands in the rat brain was saturable, specific, and selective to SERT. Specific binding in the rat hypothalamus peaked at 5.6 for ligand 16 and 4.4 for 18b at 90 min after radioactivity administration. For ligand 18a, this same ratio was 8.4 at 120 min postinjection, while compound 18c displayed a lower specific binding ratio of 2.4. In summary, four F-18-labeled ligands were prepared and evaluated as candidate PET imaging agents for SERT. Among these four ligands, three appear to be promising radioligands suitable for the labeling of SERT in vivo, with 18a providing a higher specific binding in vivo than 16 or 18b.
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Affiliation(s)
- Yiyun Huang
- Department of Psychiatry and Radiology, Columbia University College of Physicians and Surgeons, New York, New York 10032, USA
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Brust P, Hinz R, Kuwabara H, Hesse S, Zessin J, Pawelke B, Stephan H, Bergmann R, Steinbach J, Sabri O. In vivo measurement of the serotonin transporter with (S)-([18F]fluoromethyl)-(+)-McN5652. Neuropsychopharmacology 2003; 28:2010-9. [PMID: 12931143 DOI: 10.1038/sj.npp.1300281] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The radiolabeled serotonin transporter (SERT) ligand [(11)C](+)-McN5652 has recently been used in clinical positron emission tomography (PET) studies for SERT imaging. However, this radioligand offers disadvantages in routine clinical settings because of its short radioisotope half-life (eg PET facilities within hospitals without a cyclotron need to acquire such radioligands from distant cyclotron units for clinical use). S-([(18)F]fluoromethyl)-(+)-McN5652 ([(18)F](+)-FMe-McN5652) is an analogue which has been synthesized newly, and has a significantly longer radioisotope half-life. In the porcine brain, it demonstrates the same characteristic distribution pattern of serotonin-uptake sites like the (11)C-labeled congener with the highest binding in the midbrain and thalamus and the lowest in the cerebellum and occipital cortex. It shows a 30% higher blood-brain transfer and a slower peripheral metabolism than [(11)C](+)-McN5652. Rather uniform brain binding was observed after injection of the pharmacologically inactive radiolabeled enantiomer, or after pretreatment with the highly selective SERT inhibitor citalopram. The norepinephrine uptake inhibitor maprotiline did not show any inhibitory effect. Using a one-tissue compartment model (K(1), k"(2)) or a two-tissue compartment model (K(1) to k(4)) with or without constraints for calculation, the regional binding parameters of [(11)C](+)-McN5652 and [(18)F](+)-FMe-McN5652 are highly correlated among each other and with the SERT density, as determined by in vitro binding of [(3)H]citalopram. Using constraints to correct for the free fraction and nonspecific binding of the radiotracers, a considerable increase of the midbrain-occipital cortex ratios with higher values for [(18)F](+)-FMe-McN5652 compared to [(11)C](+)McN5652 was revealed. It is concluded that [(18)F](+)-FMe-McN5652 has better features than [(11)C](+)McN5652 for SERT imaging with PET.
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Affiliation(s)
- P Brust
- Institute of Interdisciplinary Isotope Research, Leipzig, Germany.
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