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Kanwal A, Afzal U, Zubair M, Imran M, Rasool N. Synthesis of anti-depressant molecules via metal-catalyzed reactions: a review. RSC Adv 2024; 14:6948-6971. [PMID: 38410364 PMCID: PMC10895647 DOI: 10.1039/d3ra06391g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2023] [Accepted: 02/07/2024] [Indexed: 02/28/2024] Open
Abstract
Depression is one of the most mutilating conditions in the world today. It has been difficult to make advancements toward better, more effective therapies since the introduction of antidepressant medicines in the late 1950s. One important field of medicinal chemistry is the synthesis of antidepressant molecules through metal-catalyzed procedures. The important role that different transition metals, including iron, nickel, ruthenium, and others, serve as catalysts in the synthesis of antidepressants is examined in this review. Key structural motifs included in antidepressant drugs such as tricyclic antidepressants (TCAs), selective serotonin reuptake inhibitors (SSRIs), and others can be synthesized in a variety of effective ways using metal-catalyzed steps. This review examines current developments in the catalytic synthesis of antidepressants and their potential application over the previous thirteen years.
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Affiliation(s)
- Aqsa Kanwal
- Department of Chemistry, Government College University Faisalabad 38000 Pakistan +92-3085448384
| | - Uzma Afzal
- Department of Chemistry, Government College University Faisalabad 38000 Pakistan +92-3085448384
| | - Muhammad Zubair
- Department of Chemistry, Government College University Faisalabad 38000 Pakistan +92-3085448384
| | - Muhammad Imran
- Chemistry Department, Faculty of Science, King Khalid University P.O. Box 9004 Abha 61413 Saudi Arabia
| | - Nasir Rasool
- Department of Chemistry, Government College University Faisalabad 38000 Pakistan +92-3085448384
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2
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Liu C, Zhang L, Cao L, Xiong Y, Ma Y, Cheng R, Ye J. Iridium-catalyzed enantioselective synthesis of chiral γ-amino alcohols and intermediates of (S)-duloxetine, (R)-fluoxetine, and (R)-atomoxetine. Commun Chem 2022; 5:63. [PMID: 36697664 PMCID: PMC9814375 DOI: 10.1038/s42004-022-00678-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2021] [Accepted: 04/26/2022] [Indexed: 02/01/2023] Open
Abstract
Chiral γ-amino alcohols are the prevalent structural motifs and building blocks in pharmaceuticals and bioactive molecules. Enantioselective hydrogenation of β-amino ketones provides a straightforward and powerful tool for the synthesis of chiral γ-amino alcohols, but the asymmetric transformation is synthetically challenging. Here, a series of tridentate ferrocene-based phosphine ligands bearing modular and tunable unsymmetrical vicinal diamine scaffolds were designed, synthesized, and evaluated in the iridium-catalyzed asymmetric hydrogenation of β-amino ketones. The system was greatly effective to substrates with flexible structure and functionality, and diverse β-tertiary-amino ketones and β-secondary-amino ketones were hydrogenated smoothly. The excellent reactivities and enantioselectivities were achieved in the asymmetric delivery of various chiral γ-amino alcohols with up to 99% yields, >99% ee values, and turnover number (TON) of 48,500. The gram-scale reactions with low catalyst loading showed the potential application in industrial synthesis of chiral drugs, such as (S)-duloxetine, (R)-fluoxetine, and (R)-atomoxetine.
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Affiliation(s)
- Chengyu Liu
- grid.28056.390000 0001 2163 4895Engineering Research Centre of Pharmaceutical Process Chemistry, Ministry of Education, Shanghai Key Laboratory of New Drug Design, School of Pharmacy, East China University of Science and Technology, Shanghai, China
| | - Lei Zhang
- grid.28056.390000 0001 2163 4895Engineering Research Centre of Pharmaceutical Process Chemistry, Ministry of Education, Shanghai Key Laboratory of New Drug Design, School of Pharmacy, East China University of Science and Technology, Shanghai, China
| | - Liming Cao
- grid.28056.390000 0001 2163 4895Engineering Research Centre of Pharmaceutical Process Chemistry, Ministry of Education, Shanghai Key Laboratory of New Drug Design, School of Pharmacy, East China University of Science and Technology, Shanghai, China
| | - Yan Xiong
- grid.28056.390000 0001 2163 4895School of Chemical Engineering, East China University of Science and Technology, Shanghai, China
| | - Yueyue Ma
- grid.411851.80000 0001 0040 0205School of Biomedical and Pharmaceutical Sciences, Guangdong University of Technology, Guangzhou, China
| | - Ruihua Cheng
- grid.28056.390000 0001 2163 4895School of Chemical Engineering, East China University of Science and Technology, Shanghai, China ,grid.411851.80000 0001 0040 0205School of Biomedical and Pharmaceutical Sciences, Guangdong University of Technology, Guangzhou, China
| | - Jinxing Ye
- grid.28056.390000 0001 2163 4895Engineering Research Centre of Pharmaceutical Process Chemistry, Ministry of Education, Shanghai Key Laboratory of New Drug Design, School of Pharmacy, East China University of Science and Technology, Shanghai, China ,grid.411851.80000 0001 0040 0205School of Biomedical and Pharmaceutical Sciences, Guangdong University of Technology, Guangzhou, China
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3
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Staroń J, Pietruś W, Bugno R, Kurczab R, Satała G, Warszycki D, Lenda T, Wantuch A, Hogendorf AS, Hogendorf A, Duszyńska B, Bojarski AJ. Tuning the activity of known drugs via the introduction of halogen atoms, a case study of SERT ligands - Fluoxetine and fluvoxamine. Eur J Med Chem 2021; 220:113533. [PMID: 34049262 DOI: 10.1016/j.ejmech.2021.113533] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2020] [Revised: 04/22/2021] [Accepted: 04/27/2021] [Indexed: 11/24/2022]
Abstract
The selective serotonin reuptake inhibitors (SSRIs), acting at the serotonin transporter (SERT), are one of the most widely prescribed antidepressant medications. All five approved SSRIs possess either fluorine or chlorine atoms, and there is a limited number of reports describing their analogs with heavier halogens, i.e., bromine and iodine. To elucidate the role of halogen atoms in the binding of SSRIs to SERT, we designed a series of 22 fluoxetine and fluvoxamine analogs substituted with fluorine, chlorine, bromine, and iodine atoms, differently arranged on the phenyl ring. The obtained biological activity data, supported by a thorough in silico binding mode analysis, allowed the identification of two partners for halogen bond interactions: the backbone carbonyl oxygen atoms of E493 and T497. Additionally, compounds with heavier halogen atoms were found to bind with the SERT via a distinctly different binding mode, a result not presented elsewhere. The subsequent analysis of the prepared XSAR sets showed that E493 and T497 participated in the largest number of formed halogen bonds. The XSAR library analysis led to the synthesis of two of the most active compounds (3,4-diCl-fluoxetine 42, SERT Ki = 5 nM and 3,4-diCl-fluvoxamine 46, SERT Ki = 9 nM, fluoxetine SERT Ki = 31 nM, fluvoxamine SERT Ki = 458 nM). We present an example of the successful use of a rational methodology to analyze binding and design more active compounds by halogen atom introduction. 'XSAR library analysis', a new tool in medicinal chemistry, was instrumental in identifying optimal halogen atom substitution.
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Affiliation(s)
- Jakub Staroń
- Maj Institute of Pharmacology, Polish Academy of Sciences, 12 Smętna Street, 31-343, Kraków, Poland.
| | - Wojciech Pietruś
- Maj Institute of Pharmacology, Polish Academy of Sciences, 12 Smętna Street, 31-343, Kraków, Poland
| | - Ryszard Bugno
- Maj Institute of Pharmacology, Polish Academy of Sciences, 12 Smętna Street, 31-343, Kraków, Poland
| | - Rafał Kurczab
- Maj Institute of Pharmacology, Polish Academy of Sciences, 12 Smętna Street, 31-343, Kraków, Poland
| | - Grzegorz Satała
- Maj Institute of Pharmacology, Polish Academy of Sciences, 12 Smętna Street, 31-343, Kraków, Poland
| | - Dawid Warszycki
- Maj Institute of Pharmacology, Polish Academy of Sciences, 12 Smętna Street, 31-343, Kraków, Poland
| | - Tomasz Lenda
- Maj Institute of Pharmacology, Polish Academy of Sciences, 12 Smętna Street, 31-343, Kraków, Poland
| | - Anna Wantuch
- Maj Institute of Pharmacology, Polish Academy of Sciences, 12 Smętna Street, 31-343, Kraków, Poland
| | - Adam S Hogendorf
- Maj Institute of Pharmacology, Polish Academy of Sciences, 12 Smętna Street, 31-343, Kraków, Poland
| | - Agata Hogendorf
- Maj Institute of Pharmacology, Polish Academy of Sciences, 12 Smętna Street, 31-343, Kraków, Poland
| | - Beata Duszyńska
- Maj Institute of Pharmacology, Polish Academy of Sciences, 12 Smętna Street, 31-343, Kraków, Poland
| | - Andrzej J Bojarski
- Maj Institute of Pharmacology, Polish Academy of Sciences, 12 Smętna Street, 31-343, Kraków, Poland
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4
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Li Y, Wang Z, Ding K. Minimizing Aryloxy Elimination in Rh
I
‐Catalyzed Asymmetric Hydrogenation of β‐Aryloxyacrylic Acids using a Mixed‐Ligand Strategy. Chemistry 2015; 21:16387-90. [DOI: 10.1002/chem.201503229] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2015] [Indexed: 11/11/2022]
Affiliation(s)
- Yang Li
- State Key Laboratory of Organometallic Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, 345 Lingling Road, Shanghai 200032 (P. R. China), Fax: (+21) 6416‐6128
| | - Zheng Wang
- State Key Laboratory of Organometallic Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, 345 Lingling Road, Shanghai 200032 (P. R. China), Fax: (+21) 6416‐6128
| | - Kuiling Ding
- State Key Laboratory of Organometallic Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, 345 Lingling Road, Shanghai 200032 (P. R. China), Fax: (+21) 6416‐6128
- Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), Tianjin 300071 (P. R. China)
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Shutske GM. Overview Central & Peripheral Nervous System: Recent developments in serotonin reuptake inhibitors. Expert Opin Ther Pat 2008. [DOI: 10.1517/13543776.4.4.335] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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7
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Lakshmi B, Kung MP, Lieberman B, Zhao J, Waterhouse R, Kung HF. (R)-N-Methyl-3-(3-(125)I-pyridin-2-yloxy)-3-phenylpropan-1-amine: a novel probe for norepinephrine transporters. Nucl Med Biol 2007; 35:43-52. [PMID: 18158942 DOI: 10.1016/j.nucmedbio.2007.08.007] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2007] [Revised: 07/20/2007] [Accepted: 08/30/2007] [Indexed: 11/19/2022]
Abstract
Alterations in serotonin and norepinephrine neuronal functions have been observed in patients with major depression. Several antidepressants bind to both serotonin transporters and norepinephrine transporters (NET). The ability to image NET in the human brain would be a useful step toward understanding how alterations in NET relate to disease. In this study, we report the synthesis and characterization of a new series of derivatives of iodonisoxetine, a known radioiodinated probe. The most promising, (R)-N-methyl-3-(3-iodopyridin-2-yloxy)-3-phenylpropylamine (PYINXT), displayed a high and saturable binding to NET, with a K(d) value of 0.53+/-0.03 nM. Biodistribution studies of (R)-N-methyl-3-(3-(125)I-pyridin-2-yloxy)-3-phenylpropan-1-amine in rats showed moderate initial brain uptake (0.54% dose/organ at 2 min) with a relatively fast washout from the brain (0.16% dose/organ at 2 h) as compared to [(125)I]INXT. The hypothalamus (a NET-rich region)-to-striatum (a region devoid of NET) ratio was found to be 2.14 at 4 h after intravenous injection. Preliminary results suggest that this improved iodinated ligand, when labeled with (123)I, may be useful for mapping NET-binding sites with single photon emission computed tomography in the living human brain.
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Affiliation(s)
- Balagopal Lakshmi
- Department of Radiology, University of Pennsylvania, Philadelphia, PA 19104, USA
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8
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Filannino MA, Matarrese M, Turolla EA, Masiello V, Moresco RM, Todde S, Verza E, Magni F, Cattaneo A, Bachi A, Kienle MG, Fazio F. Synthesis and carbon-11 labeling of (R)- and (S)-thionisoxetine, norepinephrine reuptake inhibitors, potential radioligands for positron emission tomography. Appl Radiat Isot 2007; 65:1232-9. [PMID: 17646106 DOI: 10.1016/j.apradiso.2007.06.004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2007] [Accepted: 06/11/2007] [Indexed: 11/28/2022]
Abstract
Standards and des-methyl precursors of (R)- and (S)-thionisoxetine, potent and selective norepinephrine reuptake inhibitors, were synthesized and radiolabeled with carbon-11. Both enantiomers of the N-methyl-3-(2-thiomethylphenoxy)-3-phenylpropanamine and the 3-(2-thiomethylphenoxy)-3-phenylpropylamine were obtained via multi-step syntheses, while the radiosyntheses were carried out using [11C]CH3I. The radiochemical yields were 26%, decay corrected and the specific radioactivity ranging from 2 to 3 Ci/micromol. The HPLC analyses were performed using a chiral column: during the radiolabeling, no racemization occurred and the isomers were synthesized with high enantiomeric purity.
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Affiliation(s)
- Maria Azzurra Filannino
- Institute of Molecular Bioimaging and Physiology, CNR, University of Milano-Bicocca, San Raffaele Scientific Institute, Via Olgettina 60, 20132 Milan, Italy
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9
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Zea-Ponce Y, Baldwin RM, Miliust RA, Bakthavachalam V, Innis RB. [123I]iodomethane, a main product in the synthesis of 5-[123I]iodo-6-nitroquipazine by iododestannylation. J Labelled Comp Radiopharm 2006. [DOI: 10.1002/jlcr.2580360405] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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10
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Mathis CA, Enas JD, Hanrahan SM, Akgün E. Synthesis of 123I-and labelled 5-iodo-6-nitroquipazine. J Labelled Comp Radiopharm 2006. [DOI: 10.1002/jlcr.2580341003] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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11
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Ding YS, Fowler J. New-generation radiotracers for nAChR and NET. Nucl Med Biol 2006; 32:707-18. [PMID: 16243646 DOI: 10.1016/j.nucmedbio.2005.04.017] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2005] [Revised: 04/29/2005] [Accepted: 04/30/2005] [Indexed: 01/10/2023]
Abstract
Advances in radiotracer chemistry and instrumentation have merged to make positron emission tomography (PET) a powerful tool in the biomedical sciences. Positron emission tomography has found increased application in the study of drugs affecting the brain and whole body, including the measurement of drug pharmacokinetics (using a positron-emitter-labeled drug) and drug pharmacodynamics (using a labeled tracer). Thus, radiotracers are major scientific tools enabling investigations of molecular phenomena, which are at the heart of understanding human disease and developing effective treatments; however, there is evidently a bottleneck in translating basic research to clinical practice. In the meantime, the poor ability to predict the in vivo behavior of chemical compounds based on their log P's and affinities emphasizes the need for more knowledge in this area. In this article, we focus on the development and translation of radiotracers for PET studies of the nicotinic acetylcholine receptor (nAChR) and the norepinephrine transporter (NET), two molecular systems that urgently need such an important tool to better understand their functional significance in the living human brain.
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Affiliation(s)
- Yu-Shin Ding
- Chemistry Department, Brookhaven National Laboratory, Upton, NY 11973, USA.
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12
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Kanegawa N, Kiyono Y, Kimura H, Sugita T, Kajiyama S, Kawashima H, Ueda M, Kuge Y, Saji H. Synthesis and evaluation of radioiodinated (S,S)-2-(α-(2-iodophenoxy)benzyl)morpholine for imaging brain norepinephrine transporter. Eur J Nucl Med Mol Imaging 2006; 33:639-47. [PMID: 16523308 DOI: 10.1007/s00259-005-0017-y] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2005] [Accepted: 09/28/2005] [Indexed: 10/24/2022]
Abstract
PURPOSE Abnormality of the brain norepinephrine transporter (NET) has been reported in several psychiatric and neuronal disorders. Since NET is an important target for the diagnosis of these diseases, the development of radiopharmaceuticals for imaging of brain NET has been eagerly awaited. In this study, we synthesized (S,S)-2-(alpha-(2-iodophenoxy)benzyl)morpholine [(S,S)-IPBM], a derivative of reboxetine iodinated at position 2 of the phenoxy ring, and evaluated its potential as a radiopharmaceutical for imaging brain NET using SPECT. METHODS (S,S)-(123/125)I-IPBM was synthesized in a halogen exchange reaction. The affinity and selectivity of (S,S)-IPBM for NET was measured by assaying the displacement of (3)H-nisoxetine and (S,S)-(125)I-IPBM from the binding site in rat brain membrane, respectively. The biodistribution of (S,S)-(125)I-IPBM was also determined in rats. Furthermore, SPECT studies with (S,S)-(123)I-IPBM were carried out in the common marmoset. RESULTS (S,S)-(125)I-IPBM was prepared with high radiochemical yields (65%) and high radiochemical purity (>98%). (S,S)-IPBM showed high affinity and selectivity for NET in the binding assay experiments. In biodistribution experiments, (S,S)-(125)I-IPBM showed rapid uptake in the brain, and the regional cerebral distribution was consistent with the density of NET. The administration of nisoxetine, a selective NET-binding agent, decreased the accumulation of (S,S)-(125)I-IPBM in the brain, but the administration of selective serotonin transporter and dopamine transporter binding agents caused no significant changes in the accumulation. Moreover, (S,S)-(123)I-IPBM allowed brain NET imaging in the common marmoset with SPECT. CONCLUSION These results suggest that (S,S)-(123)I-IPBM is a potential SPECT radiopharmaceutical for imaging brain NET.
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Affiliation(s)
- Naoki Kanegawa
- Department of Patho-Functional Bioanalysis, Graduate School of Pharmaceutical Sciences, Kyoto University, Sakyo-ku, Kyoto, 606-8501, Japan
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13
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Schou M, Pike VW, Varrone A, Gulyás B, Farde L, Halldin C. Synthesis and PET evaluation of (R)-[S-methyl-11C]thionisoxetine, a candidate radioligand for imaging brain norepinephrine transporters. J Labelled Comp Radiopharm 2006. [DOI: 10.1002/jlcr.1128] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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14
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Ding YS, Lin KS, Logan J, Benveniste H, Carter P. Comparative evaluation of positron emission tomography radiotracers for imaging the norepinephrine transporter: (S,S) and (R,R) enantiomers of reboxetine analogs ([11C]methylreboxetine, 3-Cl-[11C]methylreboxetine and [18F]fluororeboxetine), (R)-[11C]nisoxetine, [11C]oxaprotiline and [11C]lortalamine. J Neurochem 2005; 94:337-51. [PMID: 15998285 DOI: 10.1111/j.1471-4159.2005.03202.x] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
We have synthesized and evaluated several new ligands for imaging the norepinephrine transporter (NET) system in baboons with positron emission tomography (PET). Ligands possessing high brain penetration, high affinity and selectivity, appropriate lipophilicity (log P = 1.0-3.5), high plasma free fraction and reasonable stability in plasma were selected for further studies. Based on our characterization studies in baboons, including 11C-labeled (R)-nisoxetine (Nis), oxaprotiline (Oxap), lortalamine (Lort) and new analogs of methylreboxetine (MRB), in conjunction with our earlier evaluation of 11C and 18F derivatives of reboxetine, MRB and their individual (R,R) and (S,S) enantiomers, we have identified the superiority of (S,S)-[11C]MRB and the suitability of MRB analogs [(S,S)-[11C]MRB > (S,S)-[11C]3-Cl-MRB > (S,S)-[18F]fluororeboxetine] as potential NET ligands for PET. In contrast, Nis, Oxap and Lort displayed high uptake in striatum (higher than in thalamus). The use of these ligands is further limited by high non-specific binding and relatively low specific signal, as is characteristic of many earlier NET ligands. Thus, to our knowledge (S,S)-[11C]MRB remains by far the most promising NET ligand for PET studies.
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Affiliation(s)
- Yu-Shin Ding
- Chemistry Department, Brookhaven National Laboratory, Upton, New York 11973, USA.
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15
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Jing Q, Zhang X, Sun J, Ding K. Bulky Achiral Triarylphosphines Mimic BINAP in Ru(II)- Catalyzed Asymmetric Hydrogenation of Ketones. Adv Synth Catal 2005. [DOI: 10.1002/adsc.200505054] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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16
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Kung MP, Choi SR, Hou C, Zhuang ZP, Foulon C, Kung HF. Selective binding of 2-[125I]iodo-nisoxetine to norepinephrine transporters in the brain. Nucl Med Biol 2004; 31:533-41. [PMID: 15219270 DOI: 10.1016/j.nucmedbio.2004.03.001] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2003] [Revised: 03/06/2004] [Accepted: 03/07/2004] [Indexed: 10/26/2022]
Abstract
A radioiodinated ligand, (R)-N-methyl-(2-[(125)I]iodo-phenoxy)-3-phenylpropylamine, [(125)I]2-INXT, targeting norepinephrine transporters (NET), was successfully prepared. A no-carrier-added product, [(125)I]2-INXT, displayed a saturable binding with a high affinity (K(d)=0.06 nM) in the homogenates prepared from rat cortical tissues as well as from LLC-PK(1) cells expressing NET. A relatively low number of binding sties (B(max)=55 fmol/mg protein) measured with [(125)I]2-INXT in rat cortical homogenates is consistent with the value reported for a known NET ligand, [(3)H]nisoxetine. Competition studies with various compounds on [(125)I]2-INXT binding clearly confirmed the pharmacological specificity and selectivity for NET binding sites. Following a tail-vein injection of [(125)I]2-INXT in rats, a good initial brain uptake was observed (0.56% dose at 2 min) followed by a slow washout from the brain (0.2% remained at 3 hours post-injection). The hypothalamus (a NET-rich region) to striatum (a region devoid of NET) ratio was 1.5 at 3 hours post-i.v. injection. Pretreatment of rats with nisoxetine significantly inhibited the uptake of [(125)I]2-INXT (70-100% inhibition) in locus coeruleus, hypothalamus and raphe nuclei, regions known to have a high density of NET; whereas escitalopram, a serotonin transporter ligand, did not show a similar effect. Ex vivo autoradiography of rat brain sections of [(125)I]2-INXT (at 3 hours after an i.v. injection) displayed an excellent regional brain localization pattern corroborated to the specific NET distribution in the brain. The specific brain localization was significantly reduced by a dose of nisoxetine pretreatment. Taken together, the data suggest that [(123)I]2-INXT may be useful for mapping NET binding sites in the brain.
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Affiliation(s)
- Mei-Ping Kung
- Department of Radiology, University of Pennsylvania, Philadelphia, PA 19104, USA
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17
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Ding YS, Lin KS, Garza V, Carter P, Alexoff D, Logan J, Shea C, Xu Y, King P. Evaluation of a new norepinephrine transporter PET ligand in baboons, both in brain and peripheral organs. Synapse 2003; 50:345-52. [PMID: 14556239 DOI: 10.1002/syn.10281] [Citation(s) in RCA: 76] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Reboxetine is a specific norepinephrine transporter (NET) inhibitor and has been marketed in several countries as a racemic mixture of the (R,R) and (S,S) enantiomers for the treatment of depression. Its methyl analog (methylreboxetine, MRB) has been shown to be more potent than reboxetine itself. We developed a nine-step synthetic procedure to prepare the normethyl precursor, which was used to synthesize [11C]O-methylreboxetine ([11C]MRB). We also developed a convenient resolution method using a chiral HPLC column to resolve the racemic precursor to obtain enantiomerically pure individual precursors that lead to the individual enantiomers (R,R)-[11C]MRB and (S,S)-[11C]MRB. Here we report an evaluation of the racemate and individual enantiomers of [11C]MRB as radioligands for PET imaging studies of NET systems in baboons both in brain and in peripheral organs. The relative regional distribution of the radioactivity after injection of [11C]MRB in baboon brain is consistent with the known distribution of NET. For a NET-poor region such as striatum, there were no significant changes in the striatal uptakes with and without the nisoxetine pretreatment. In contrast, a significant blocking effect was observed in NET-rich regions such as thalamus and cerebellum after injection of racemic [11C]MRB, with an even more dramatic effect after injection of (S,S)-[11C]MRB. These results, along with the fact that there was no regional specificity and no blocking effect by nisoxetine for (R,R)-[11C]MRB, suggest the enantioselectivity of MRB in vivo, consistent with previous in vitro and in vivo studies in rodents. PET studies of baboon torso revealed a blocking effect by desipramine only in the heart, a NET-rich organ, after injection of (S,S)-[11C]MRB, but not the (R,R)-isomer. These studies demonstrate that the use of (S,S)-[11C]MRB would allow a better understanding of the role that NET plays in living systems.
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Affiliation(s)
- Yu-Shin Ding
- Chemistry Department, Brookhaven National Laboratory, Upton, New York 11973, USA.
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18
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Kiyono Y, Kanegawa N, Kawashima H, Fujiwara H, Iida Y, Nishimura H, Saji H. A new norepinephrine transporter imaging agent for cardiac sympathetic nervous function imaging: radioiodinated (R)-N-methyl-3-(2-iodophenoxy)-3-phenylpropanamine. Nucl Med Biol 2003; 30:697-706. [PMID: 14499327 DOI: 10.1016/s0969-8051(03)00085-4] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Changes of the cardiac norepinephrine transporter (NET) have been reported in several cardiac failures. (R)-N-methyl-3-(2-iodophenoxy)-3-phenylpropanamine (MIPP), the 3-phenoxy-3-phenylpropylamine analogue iodinated at the 2-position of the phenoxy ring, was synthesized and evaluated as a potential radiopharmaceutical for investigating the cardiac norepinephrine transporter by single photon emission computed tomography (SPECT). (R)-[(125)I]MIPP was synthesized via a halogen exchange reaction under no-carrier-added conditions and purified by high-performance liquid chromatography (HPLC) with high radiochemical yield (60%) and high radiochemical purity (> 98%). The binding affinity of (R)-MIPP for cardiac NET was measured in terms of the displacement of [(3)H]desipramine and (R)-[(125)I]MIPP from binding sites in rat heart membranes. The binding data revealed that the affinity of (R)-MIPP was 5 times that of nisoxetine which is a selective NET inhibitor. In biodistribution studies, (R)-[(125)I]MIPP showed a high uptake followed by rapid clearance in the heart. (R)-[(125)I]MIPP binding sites were saturable and the administration of nisoxetine and desipramine, selective NET inhibitors, decreased the cardiac accumulation of (R)-[(125)I]MIPP. These results suggested that (R)-[(123)I]MIPP may be an useful radiopharmaceutical for imaging cardiac sympathetic nervous functions.
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Affiliation(s)
- Yasushi Kiyono
- Radioisotopes Research Laboratory, Kyoto University Hospital, Faculty of Medicine, Kyoto University, Kyoto, Japan
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Schou M, Halldin C, Sóvágó J, Pike VW, Gulyás B, Mozley PD, Johnson DP, Hall H, Innis RB, Farde L. Specific in vivo binding to the norepinephrine transporter demonstrated with the PET radioligand, (S,S)-[11C]MeNER. Nucl Med Biol 2003; 30:707-14. [PMID: 14499328 DOI: 10.1016/s0969-8051(03)00079-9] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
(S,S)-2-(alpha-(2-Methoxyphenoxy)benzyl)morpholine (MeNER), an O-methyl analog of the selective and potent norepinephrine transporter (NET) inhibitor, (S,S)-reboxetine, and its less active enantiomer, (R,R)-MeNER, have each been radiolabeled by O-methylation of their corresponding phenolic precursors in good yields from [(11)C]methyl iodide or [(11)C]methyl triflate. Radiochemical purities were >99% and specific radioactivity at time of injection was about 74 GBq/micromol. Autoradiographic examination of (S,S)-[(11)C]MeNER binding to human brain slices post mortem indicated specific binding in a brain region including the locus coeruleus. PET examination of both [(11)C]MeNER enantiomers in a cynomolgus monkey demonstrated a higher specific binding of the (S,S)-enantiomer with ratios of 1.4-1.6 in the lower brainstem, mesencephalon and thalamus to striatum. Pretreatment with the NET ligand, desipramine, decreased the specific binding of (S,S)-[(11)C]MeNER. Labeled metabolites of [(11)C]MeNER were all more polar. (S,S)-[(11)C]MeNER is a good lead compound in the search for a selective radioligand for quantitation of NET in the human brain in vivo.
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Affiliation(s)
- Magnus Schou
- Karolinska Institutet, Department of Clinical Neuroscience, Psychiatry Section, Karolinska Hospital, S-17176 Stockholm, Sweden
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20
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Wilson AA, Johnson DP, Mozley D, Hussey D, Ginovart N, Nobrega J, Garcia A, Meyer J, Houle S. Synthesis and in vivo evaluation of novel radiotracers for the in vivo imaging of the norepinephrine transporter. Nucl Med Biol 2003; 30:85-92. [PMID: 12623106 DOI: 10.1016/s0969-8051(02)00420-1] [Citation(s) in RCA: 76] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
The (R,R) and (S,S) enantiomers of 2-[(2-methoxyphenoxy)phenylmethyl]morpholine (MeNER) have been radiolabelled with carbon-11 in good yield and at high specific activity. These radiotracers are close analogues of reboxetine, a potent and selective ligand for the norepinephrine transporter (NET). They were examined as potential ligands for imaging NET in vivo by positron emission tomography (PET). The in vivo brain distribution of both [(11)C]-labeled enantiomers were evaluated in rats. Following tail-vein injection of the (R,R)-enantiomer regional brain uptake and washout of radioactivity was homogeneous at all time points examined (5-60 min). In contrast, administration of the (S,S)-enantiomer produced a heterogeneous distribution of radioactivity in brain with highest uptake in the hypothalamus, a NET rich region, and lowest uptake in the striatum, a brain region devoid of NET. Hypothalamus to striatum ratios of 2.5 to one were achieved at 60 min post injection of (S,S)-[(11)C]-MeNER. Pre-injection of the norepinephrine reuptake inhibitors, reboxetine or desipramine, reduced hypothalamus to striatum ratios to near unity while reuptake inhibitors of dopamine and serotonin had no significant effect on binding. In vitro autoradiography studies (rat brain slices) with (S,S)-[(11)C]-MeNER produced a regional distribution pattern that was consistent with the reported distribution of NET. (S,S)-[(11)C]-MeNER has the potential to be the first successful PET ligand to image NET.
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Affiliation(s)
- Alan A Wilson
- PET Centre, Centre for Addiction and Mental Health and Department of Psychiatry, University of Toronto, Toronto, Ontario M5T 1R8, Canada.
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21
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Oya S, Choi SR, Coenen H, Kung HF. New PET imaging agent for the serotonin transporter: [(18)F]ACF (2-[(2-amino-4-chloro-5-fluorophenyl)thio]-N,N-dimethyl-benzenmethanamine). J Med Chem 2002; 45:4716-23. [PMID: 12361398 DOI: 10.1021/jm020167y] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A new F-18-labeled phenylthiophenyl derivative specific for imaging of serotonin transporters (SERT) in the brain by positron emission tomography (PET) is described. Fluorinated phenylthiophenyl derivative, ACF, 2-[(2-amino-4-chloro-5-fluorophenyl)thio]-N,N-dimethyl-benzenmethanamine, was prepared by first coupling 2,5-dichloro-4-nitroaniline with 2-mercapto-N,N-dimethylbenzamide. The amino group of the coupled adduct was converted to a fluoro group through a Schiemann reaction. Subsequently, a one pot reduction of both nitro and amide groups by BH(3)-tetrahydrofuran yielded the nonradioactive ACF (yield 25%). In vitro binding assays using cell membrane homogenates of LLC cells expressing SERT, dopamine transporters (DAT), or norepinephrine transporters (NET) showed excellent binding affinity and selectivity for SERT (K(i) = 0.05, 3020, and 650 nM for SERT, DAT, and NET, respectively). For preparation of the [(18)F]ACF, the NH(2) group of the initially coupled adduct was converted to the trimethylammonium salt, which was replaced by [(18)F]fluoride in the presence of Kryptofix 222 and potassium carbonate. The final product, [(18)F]ACF, was obtained after a borane and stannous chloride reduction reaction. The combined two step reaction gave a radiochemical yield of 10-15% (EOB) and a radiochemical purity of >99%. Synthesis of the novel PET tracer, [(18)F]ACF, as a probe for binding to SERT in the brain was successfully achieved. The new tracer [(18)F]ACF showed excellent brain penetration and selective localization after an iv injection in rats (brain uptake at 2, 30, 60, 120, and 240 min was 3.27, 1.28, 0.69, 0.21, and 0.06% dose/organ, respectively). The hypothalamus/cerebellum ratio at 60 min post iv injection was 3.55. This specific localization in the hypothalamus was blocked by pretreatment of (+)McN5652. This novel ligand is a potential PET tracer for in vivo evaluation of SERT in the brain.
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Affiliation(s)
- Shunichi Oya
- Department of Radiology, University of Pennsylvania, 3700 Market Street, Room 305, Philadelphia, Pennsylvania 19104, USA
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22
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Olivier B, Soudijn W, van Wijngaarden I. Serotonin, dopamine and norepinephrine transporters in the central nervous system and their inhibitors. PROGRESS IN DRUG RESEARCH. FORTSCHRITTE DER ARZNEIMITTELFORSCHUNG. PROGRES DES RECHERCHES PHARMACEUTIQUES 2000; 54:59-119. [PMID: 10857386 DOI: 10.1007/978-3-0348-8391-7_3] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
An overview is presented on progress made in the research on neuronal transporters of serotonin, dopamine and norepinephrine in the central nervous system. Tools developed by molecular biology, such as expression of cloned transporters, their mutants and chimera in non-neuronal cells offered the opportunity to study the putative domains for binding of substrates and uptake inhibitors and discover factors in the regulation of the transporter function. The study of the distribution of monoamine transporters in human brain became possible by the development of selective radiolabelled transport inhibitors. The relationships between the chemical structure of the uptake inhibitors and the affinity for the monoamine transporters is reported, and the (potential) therapeutic applications of the compounds are discussed.
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Affiliation(s)
- B Olivier
- Dept. of Psychopharmacology, Faculty of Pharmacy, Utrecht University, The Netherlands
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23
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Zhuang Z, Choi S, Hou C, Mu M, Kung M, Acton PD, Kung HF. A novel serotonin transporter ligand: (5-iodo-2-(2-dimethylaminomethylphenoxy)-benzyl alcohol. Nucl Med Biol 2000; 27:169-75. [PMID: 10773546 DOI: 10.1016/s0969-8051(99)00093-1] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
The serotonin transporters (SERT) are the primary binding sites for selective serotonin reuptake inhibitors, commonly used antidepressants such as fluoxetine, sertraline, and paroxetine. Imaging of SERT with positron emission tomography and single photon emission computed tomography in humans would provide a useful tool for understanding how alterations of this system are related to depressive illnesses and other psychiatric disorders. In this article the synthesis and characterization of [(125)I]ODAM [(5-iodo-2-(2-dimethylaminomethylphenoxy)-benzyl alcohol, 9)] as an imaging agent in the evaluation of central nervous system SERT are reported. A new reaction scheme was developed for the preparation of compound 9, ODAM, and the corresponding tri-n-butyltin derivative 10. Upon reacting 10 with hydrogen peroxide and sodium[(125)I]iodide, the radiolabeled [(125)95%). In an initial binding study using cortical membrane homogenates of rat brain, ODAM displayed a good binding affinity with a value of K(i) = 2.8 +/- 0.88 nM. Using LLC-PK(1) cells specifically expressing the individual transporter (i.e. dopamine [DAT], norepinephrine [NET], and SERT, respectively), ODAM showed a strong inhibition on SERT (K(i) = 0.12 +/- 0.02 nM). Inhibition constants for the other two transporters were lower (K(i) = 3.9 +/- 0.7 microM and 20.0 +/- 1.9 nM for DAT and NET, respectively). Initial biodistribution study in rats after an intravenous (IV) injection of [(125)I]ODAM showed a rapid brain uptake and washout (2.03, 1.49, 0.79, 0.27, and 0.07% dose/organ at 2, 30, 60, 120, and 240 min, respectively). The hypothalamus region where the serotonin neurons are located exhibited a high specific uptake. Ratios of hypothalamus-cerebellum/cerebellum based on percent dose per gram of these two regions showed values of 0.35, 0. 86, 0.86, 0.63, and 0.34 at 2, 30, 60, 120, and 240 min, post-IV injection, respectively. The specific uptake in hypothalamus can be effectively blocked by pretreatment of known SERT ligands. The results suggest that this novel ligand displays desirable in vitro and in vivo properties as a potential SERT imaging agent.
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Affiliation(s)
- Z Zhuang
- Departments of Radiology and Pharmacology, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
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24
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Oya S, Kung MP, Acton PD, Mu M, Hou C, Kung HF. A new single-photon emission computed tomography imaging agent for serotonin transporters: [123I]IDAM, 5-iodo-2-((2-((dimethylamino)methyl)phenyl)thio)benzyl alcohol. J Med Chem 1999; 42:333-5. [PMID: 9986702 DOI: 10.1021/jm9806751] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- S Oya
- Departments of Radiology and Pharmacology, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
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25
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XIIth international symposium on radiopharmaceutical chemistry: Abstracts and programme. J Labelled Comp Radiopharm 1997. [DOI: 10.1002/jlcr.2580400201] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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26
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5-HT transporter. ACTA ACUST UNITED AC 1997. [DOI: 10.1016/s0165-7208(97)80019-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/13/2023]
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28
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Kung MP, Essman WD, Frederick D, Meegalla S, Goodman M, Mu M, Lucki I, Kung HF. IPT: a novel iodinated ligand for the CNS dopamine transporter. Synapse 1995; 20:316-24. [PMID: 7482291 DOI: 10.1002/syn.890200405] [Citation(s) in RCA: 49] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
An iodinated cocaine derivative, N-(3'-iodopropen-2'-yl)-2 beta-carbomethoxy-3 beta-(4-chlorophenyl) tropane (IPT), was evaluated as a probe for in vitro and in vivo labeling of dopamine (DA) and serotonin (5-HT) transporters in Sprague-Dawley rat brain. Saturation analysis of [125I]IPT in rat striatal homogenates, in two different buffer solutions, Tris-HCl and phosphate, demonstrated a one-site binding with affinities (Kd) of 0.25 +/- 0.02 and 0.16 +/- 0.02 nM and densities (Bmax) of 939 +/- 161 and 1,982 +/- 137 fmol/mg protein, respectively. Competition by known DA transporter ligands showed a rank order of RTI-55 > IPT > GBR12909 > mazindol > (-)cocaine. Binding to 5-HT transporter sites was evaluated in rat cortical homogenates. Saturation experiment results showed a single site with a Kd value of 1.2 +/- 0.2 nM and a Bmax value of 100 +/- 20 fmol/mg protein. The rank order of potency of several monoamine uptake inhibitors (paroxetine > fluoxetine > mazindol > R-nisoxetine > GBR12909) suggests that [125I] IPT labels 5-HT transporters in rat cortical homogenates. Both ex vivo and in vitro autoradiographic studies revealed high densities of [125I]IPT binding sites in the caudate nucleus, putamen, olfactory tubercle and nucleus accumbens, areas known to be rich in dopaminergic innervation. Moderate accumulation of activity was also observed in the substantia nigra. The dorsal raphe, a region with a high density of 5-HT innervation, was labeled using in vitro autoradiography with [125I]IPT, but the labeling using ex vivo autoradiography was less prominent at 30 min postinjection and not noticeable at 60 min postinjection.(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- M P Kung
- Department of Radiology, University of Pennsylvania, School of Medicine, Philadelphia 19104, USA
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29
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Gehlert DR, Hemrick-Luecke SK, Schober DA, Krushinski J, Howbert JJ, Robertson DW, Wong DT, Fuller RW. (R)-thionisoxetine, a potent and selective inhibitor of central and peripheral norepinephrine uptake. Life Sci 1995; 56:1915-20. [PMID: 7746100 DOI: 10.1016/0024-3205(95)00166-4] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Inhibitors of neuronal norepinephrine (NE) uptake are useful for the treatment of a variety of diseases including depression and urinary incontinence. In the present study, we synthesized and evaluated a novel analog of the potent and selective NE uptake inhibitor, nisoxetine. Thionisoxetine more potently inhibited the uptake of [3H]-NE into hypothalamic synaptosomes and [3H]-nisoxetine binding to the NE transporter than (R)-nisoxetine. The (R) enantiomer of this compound was significantly more potent than the (S) enantiomer, having a Ki of 0.20 nM in [3H]-nisoxetine binding. The (R) enantiomer was approximately 70-fold more potent in inhibiting [3H]-NE uptake when compared to [3H]-5HT uptake. In rats, (R)-thionisoxetine prevented hypothalamic NE depletion by 6-hydroxydopamine with an ED50 of 0.21 mg/kg. Depletion of NE in peripheral nerves was accomplished by the administration of metaraminol to rats. In this paradigm, (R)-thionisoxetine prevented the depletion of heart NE with an ED50 of 3.4 mg/kg and urethral NE with an ED50 of 1.2 mg/kg. Thus, (R)-thionisoxetine is a potent and selective inhibitor of NE uptake in both central and peripheral tissues.
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Affiliation(s)
- D R Gehlert
- Lilly Research Laboratories, A Division of Eli Lilly and Company, Indianapolis, IN 46285, USA
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Asymmetric syntheses via chiral organoboranes based on α-pinene. ACTA ACUST UNITED AC 1995. [DOI: 10.1016/s1874-5148(06)80007-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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31
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Gehlert DR, Schober DA, Hemrick-Luecke SK, Krushinski J, Howbert JJ, Robertson DW, Fuller RW, Wong DT. Novel halogenated analogs of tomoxetine that are potent and selective inhibitors of norepinephrine uptake in brain. Neurochem Int 1995; 26:47-52. [PMID: 7787762 DOI: 10.1016/0197-0186(94)00113-9] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Halogenated analogs of the potent norepinephrine (NE) uptake inhibitor, tomoxetine, were synthesized and their affinities for the serotonin (5HT) and NE uptake sites evaluated. One of the most potent was the 2-iodo substituted analog (289306) that inhibited [3H]tomoxetine binding to rat cerebral cortex with a Ki of 0.37 nM. The compound also inhibited the uptake of [3H]NE into rat hypothalamic synaptosomes with a Ki of 3.5 nM. This analog was significantly less potent at the 5HT uptake site, as exhibited by a Ki of 25 nM in the inhibition of [3H]paroxetine binding and a Ki of 121 nM in [3H]5HT uptake. The resolved (R) enantiomer (303926) was 10 times more potent as a [3H]NE uptake inhibitor and 29 times more potent as an inhibitor of [3H]tomoxetine binding than the (S) enantiomer (303884). Administration of 289306 to rats prior to an i.c.v. injection of 6-hydroxydopamine prevented the depletion of hypothalamic NE and Epi with ED50 values of 0.28 and 0.47 mg/kg, respectively. Thus, 289306 was a potent inhibitor of NE uptake in vitro and in vivo. In addition, these compounds provide structures for potential ligands for the study of NE uptake sites by autoradiography, PET or SPECT imaging.
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Affiliation(s)
- D R Gehlert
- Central Nervous System Research, Lilly Research Laboratories, Eli Lilly and Company, Indianapolis, IN 46285, USA
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32
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Mathis CA, Taylor SE, Biegon A, Enas JD. [125I]5-iodo-6-nitroquipazine: a potent and selective ligand for the 5-hydroxytryptamine uptake complex. I. In vitro studies. Brain Res 1993; 619:229-35. [PMID: 8374781 DOI: 10.1016/0006-8993(93)91616-z] [Citation(s) in RCA: 29] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
In search of a potent and selective radioiodinated ligand for the 5-hydroxytryptamine (serotonin or 5-HT) uptake complex, we synthesized and evaluated the in vitro properties of [125I]5-iodo-6-nitroquipazine. The binding properties and pharmacological profile of this radioligand were studied in rat brain homogenates, and it was found to display high affinity and selectivity for the serotonin uptake complex. Scatchard analysis of the binding data indicated a single population of sites with a Kd of 23 +/- 6 pM and a Bmax of 430 +/- 50 fmol/mg protein (mean +/- S.E.M., n = 7). Inhibitors of serotonin uptake were the most efficient competitors for [125I]5-iodo-6-nitroquipazine binding with Ki values similar in rank order and magnitude to those obtained in studies of other established serotonin uptake blockers. Inhibitors of dopamine and norepinephrine uptake as well as a wide variety of postsynaptic receptor agents were relatively ineffective in inhibiting [125I]5-iodo-6-nitroquipazine binding to rat brain membranes. Serotonin was the only monoaminergic neurotransmitter capable of effectively competing for [125I]5-iodo-6-nitroquipazine binding sites and gave a Ki value of 2.8 +/- 0.6 microM. Lesions of the serotonergic system with p-chloroamphetamine resulted in a dramatic loss (> 90%) of [125I]5-iodo-6-nitroquipazine binding to rat cortical membranes. Non-radiolabeled 5-iodo-6-nitroquipazine potently inhibited the binding of [3H]paroxetine to serotonin reuptake sites in rat cortical membranes with a Ki of 0.17 +/- 0.06 nM.(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- C A Mathis
- Center for Functional Imaging, Lawrence Berkeley Laboratory, University of California, Berkeley 94720
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