1
|
Val C, Rodríguez-García C, Prieto-Díaz R, Crespo A, Azuaje J, Carbajales C, Majellaro M, Díaz-Holguín A, Brea JM, Loza MI, Gioé-Gallo C, Contino M, Stefanachi A, García-Mera X, Estévez JC, Gutiérrez-de-Terán H, Sotelo E. Optimization of 2-Amino-4,6-diarylpyrimidine-5-carbonitriles as Potent and Selective A1 Antagonists. J Med Chem 2022; 65:2091-2106. [PMID: 35068155 PMCID: PMC8842224 DOI: 10.1021/acs.jmedchem.1c01636] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
![]()
We herein document a large collection
of 108 2-amino-4,6-disubstituted-pyrimidine
derivatives as potent, structurally simple, and highly selective A1AR ligands. The most attractive ligands were confirmed as
antagonists of the canonical cyclic adenosine monophosphate pathway,
and some pharmacokinetic parameters were preliminarilly evaluated.
The library, built through a reliable and efficient three-component
reaction, comprehensively explored the chemical space allowing the
identification of the most prominent features of the structure–activity
and structure–selectivity relationships around this scaffold.
These included the influence on the selectivity profile of the aromatic
residues at positions R4 and R6 of the pyrimidine
core but most importantly the prominent role to the unprecedented
A1AR selectivity profile exerted by the methyl group introduced
at the exocyclic amino group. The structure–activity relationship
trends on both A1 and A2AARs were conveniently
interpreted with rigorous free energy perturbation simulations, which
started from the receptor-driven docking model that guided the design
of these series.
Collapse
Affiliation(s)
- Cristina Val
- Centro Singular de Investigación en Química Biolóxica e Materiais Moleculares (CiQUS), Universidade de Santiago de Compostela, Santiago de Compostela 15782, Spain
- Departamento de Química Orgánica, Universidade de Santiago de Compostela, Santiago de Compostela 15782, Spain
| | - Carlos Rodríguez-García
- Centro Singular de Investigación en Química Biolóxica e Materiais Moleculares (CiQUS), Universidade de Santiago de Compostela, Santiago de Compostela 15782, Spain
- Departamento de Química Orgánica, Universidade de Santiago de Compostela, Santiago de Compostela 15782, Spain
| | - Rubén Prieto-Díaz
- Centro Singular de Investigación en Química Biolóxica e Materiais Moleculares (CiQUS), Universidade de Santiago de Compostela, Santiago de Compostela 15782, Spain
- Departamento de Química Orgánica, Universidade de Santiago de Compostela, Santiago de Compostela 15782, Spain
- Department of Cell and Molecular Biology, Uppsala University, Uppsala 75124, Sweden
| | - Abel Crespo
- Centro Singular de Investigación en Química Biolóxica e Materiais Moleculares (CiQUS), Universidade de Santiago de Compostela, Santiago de Compostela 15782, Spain
- Departamento de Química Orgánica, Universidade de Santiago de Compostela, Santiago de Compostela 15782, Spain
| | - Jhonny Azuaje
- Centro Singular de Investigación en Química Biolóxica e Materiais Moleculares (CiQUS), Universidade de Santiago de Compostela, Santiago de Compostela 15782, Spain
- Departamento de Química Orgánica, Universidade de Santiago de Compostela, Santiago de Compostela 15782, Spain
| | - Carlos Carbajales
- Centro Singular de Investigación en Química Biolóxica e Materiais Moleculares (CiQUS), Universidade de Santiago de Compostela, Santiago de Compostela 15782, Spain
- Departamento de Química Orgánica, Universidade de Santiago de Compostela, Santiago de Compostela 15782, Spain
| | - Maria Majellaro
- Centro Singular de Investigación en Química Biolóxica e Materiais Moleculares (CiQUS), Universidade de Santiago de Compostela, Santiago de Compostela 15782, Spain
- Departamento de Química Orgánica, Universidade de Santiago de Compostela, Santiago de Compostela 15782, Spain
| | | | - José M. Brea
- Centro Singular de Investigación en Medicina Molecular y Enfermedades Crónicas (CiMUS), Universidade de Santiago de Compostela, Santiago de Compostela 15782, Spain
| | - Maria Isabel Loza
- Centro Singular de Investigación en Medicina Molecular y Enfermedades Crónicas (CiMUS), Universidade de Santiago de Compostela, Santiago de Compostela 15782, Spain
| | - Claudia Gioé-Gallo
- Centro Singular de Investigación en Química Biolóxica e Materiais Moleculares (CiQUS), Universidade de Santiago de Compostela, Santiago de Compostela 15782, Spain
- Departamento de Química Orgánica, Universidade de Santiago de Compostela, Santiago de Compostela 15782, Spain
| | - Marialessandra Contino
- Dipartimento di Farmacia-Scienze del Farmaco, Università degli Studi di Bari ALDO MORO, via Orabona 4, Bari 70125, Italy
| | - Angela Stefanachi
- Dipartimento di Farmacia-Scienze del Farmaco, Università degli Studi di Bari ALDO MORO, via Orabona 4, Bari 70125, Italy
| | - Xerardo García-Mera
- Departamento de Química Orgánica, Universidade de Santiago de Compostela, Santiago de Compostela 15782, Spain
| | - Juan C. Estévez
- Centro Singular de Investigación en Química Biolóxica e Materiais Moleculares (CiQUS), Universidade de Santiago de Compostela, Santiago de Compostela 15782, Spain
| | | | - Eddy Sotelo
- Centro Singular de Investigación en Química Biolóxica e Materiais Moleculares (CiQUS), Universidade de Santiago de Compostela, Santiago de Compostela 15782, Spain
- Departamento de Química Orgánica, Universidade de Santiago de Compostela, Santiago de Compostela 15782, Spain
| |
Collapse
|
2
|
Li J, Hong X, Li G, Conti PS, Zhang X, Chen K. PET Imaging of Adenosine Receptors in Diseases. Curr Top Med Chem 2019; 19:1445-1463. [PMID: 31284861 DOI: 10.2174/1568026619666190708163407] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2018] [Revised: 01/26/2019] [Accepted: 02/02/2019] [Indexed: 01/08/2023]
Abstract
Adenosine receptors (ARs) are a class of purinergic G-protein-coupled receptors (GPCRs). Extracellular adenosine is a pivotal regulation molecule that adjusts physiological function through the interaction with four ARs: A1R, A2AR, A2BR, and A3R. Alterations of ARs function and expression have been studied in neurological diseases (epilepsy, Alzheimer's disease, and Parkinson's disease), cardiovascular diseases, cancer, and inflammation and autoimmune diseases. A series of Positron Emission Tomography (PET) probes for imaging ARs have been developed. The PET imaging probes have provided valuable information for diagnosis and therapy of diseases related to alterations of ARs expression. This review presents a concise overview of various ARs-targeted radioligands for PET imaging in diseases. The most recent advances in PET imaging studies by using ARs-targeted probes are briefly summarized.
Collapse
Affiliation(s)
- Jindian Li
- Department of Radiology, Molecular Imaging Center, Keck School of Medicine, University of Southern California, 2250 Alcazar Street, CSC103, Los Angeles, CA 90033, United States.,State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics & Center for Molecular Imaging and Translational Medicine, School of Public Health, Xiamen University, Xiamen 361102, China
| | - Xingfang Hong
- Laboratory of Pathogen Biology, School of Basic Medical Sciences, Dali University, Dali 671000, China
| | - Guoquan Li
- Department of Radiology, Molecular Imaging Center, Keck School of Medicine, University of Southern California, 2250 Alcazar Street, CSC103, Los Angeles, CA 90033, United States
| | - Peter S Conti
- Department of Radiology, Molecular Imaging Center, Keck School of Medicine, University of Southern California, 2250 Alcazar Street, CSC103, Los Angeles, CA 90033, United States
| | - Xianzhong Zhang
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics & Center for Molecular Imaging and Translational Medicine, School of Public Health, Xiamen University, Xiamen 361102, China
| | - Kai Chen
- Department of Radiology, Molecular Imaging Center, Keck School of Medicine, University of Southern California, 2250 Alcazar Street, CSC103, Los Angeles, CA 90033, United States
| |
Collapse
|
3
|
New potent A1 adenosine receptor radioligands for positron emission tomography. Nucl Med Biol 2017; 44:69-77. [DOI: 10.1016/j.nucmedbio.2016.09.004] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2016] [Revised: 08/31/2016] [Accepted: 09/08/2016] [Indexed: 01/05/2023]
|
4
|
Mishina M, Ishiwata K. Adenosine Receptor PET Imaging in Human Brain. INTERNATIONAL REVIEW OF NEUROBIOLOGY 2014; 119:51-69. [DOI: 10.1016/b978-0-12-801022-8.00002-7] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
|
5
|
XIIth international symposium on radiopharmaceutical chemistry: Abstracts and programme. J Labelled Comp Radiopharm 2010. [DOI: 10.1002/jlcr.2580401101] [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]
|
6
|
Abstract
Advances in radiotracer chemistry have resulted in the development of novel molecular imaging probes for adenosine receptors (ARs). With the availability of these molecules, the function of ARs in human pathophysiology as well as the safety and efficacy of approaches to the different AR targets can now be determined. Molecular imaging is a rapidly growing field of research that allows the identification of molecular targets and functional processes in vivo. It is therefore gaining increasing interest as a tool in drug development because it permits the process of evaluating promising therapeutic targets to be stratified. Further, molecular imaging has the potential to evolve into a useful diagnostic tool, particularly for neurological and psychiatric disorders. This chapter focuses on currently available AR ligands that are suitable for molecular neuroimaging and describes first applications in healthy subjects and patients using positron emission tomography (PET).
Collapse
Affiliation(s)
- Andreas Bauer
- Institute of Neuroscience and Biophysics (INB-3), Research Center Jülich, 52425 Jülich, Germany.
| | | |
Collapse
|
7
|
Matsuya T, Takamatsu H, Murakami Y, Noda A, Ichise R, Awaga Y, Nishimura S. Synthesis and evaluation of [11C]FR194921 as a nonxanthine-type PET tracer for adenosine A1 receptors in the brain. Nucl Med Biol 2005; 32:837-44. [PMID: 16253808 DOI: 10.1016/j.nucmedbio.2005.06.008] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2005] [Revised: 05/31/2005] [Accepted: 06/09/2005] [Indexed: 11/18/2022]
Abstract
This report describes the synthesis of [11C]2-(1-methyl-4-piperidinyl)-6-(2-phenylpyrazolo[1,5-a]pyridin-3-yl)-3(2H)-pyridazinone ([11C]FR194921), a highly selective, nonxanthine-type adenosine A(1) receptor antagonist, used in brain imaging in rats and conscious monkeys as a potential novel PET tracer. [11C]FR194921 was successfully synthesized in 19 min after [11C]CH3I formation. The radiochemical yield was 38+/-3%; and radioactivity was 4.1+/-0.4 GBq, calculated from end of synthesis; radiochemical purity was higher than 99%; and the specific radioactivity was 25.0+/-8.1 GBq micromol(-1) (n=5). In a rat experiment, the distribution of [11C]FR194921 was higher in the hippocampus, striatum and cerebellum regions. This accumulation was significantly decreased by approximately 50% by pretreatment with 8-cyclopentyl-1,3-dipropylxanthine (DPCPX), an adenosine A1 receptor antagonist, which indicated specific binding of the radioligand to adenosine A1 receptors. In conscious monkey PET experiments, [11C]FR194921 accumulated in several regions of the brain, especially in the occipital cortex, thalamus and striatum. These results suggest that [11C]FR194921 can be used as an agent for imaging adenosine A1 receptors in vivo by positron emission tomography (PET).
Collapse
Affiliation(s)
- Takahiro Matsuya
- Basic Research Division, The Medical and Pharmacological Research Center Foundation, Ishikawa 925-0613, Japan.
| | | | | | | | | | | | | |
Collapse
|
8
|
Zhang MR, Ogawa M, Yoshida Y, Suzuki K. Selective synthesis of [2-(11)C]2-iodopropane and [1-(11)C]iodoethane using the loop method by reacting methylmagnesium bromide with [11C]carbon dioxide. Appl Radiat Isot 2005; 64:216-22. [PMID: 16194603 DOI: 10.1016/j.apradiso.2005.07.025] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2005] [Revised: 07/08/2005] [Accepted: 07/23/2005] [Indexed: 10/25/2022]
Abstract
[2-(11)C]2-iodopropane ([2-(11)C]i-PrI) and [1-(11)C]iodoethane ([1-(11)C]EtI) were selectively synthesized using the loop method by reacting methylmagnesium bromide (MeMgBr) with [11C]carbon oxide ([11C]CO2), followed by treatment with LiAlH4 and then HI. The loop method, in which a low amount of MeMgBr was used for the Grignard reaction, diminished the formation of non-radioactive iodomethane (MeI) and improved the specific activity of [2-(11)C]i-PrI and [1-(11)C]EtI. By examining the reaction temperature and time of MeMgBr with [11C]CO2 in the loop, we determined the optimal respective conditions of forming [2-(11)C]i-PrI and [1-(11)C]EtI. Moreover, [2-(11)C]i-PrI and [1-(11)C]EtI could be simultaneously synthesized at a designated ratio in one production run. These substances were obtained by gas chromatographic purification as two radiochemically pure products. All the processes from the production of [11C]CO2 to the purification of [11C]RI were automated. When we started from about 37 GBq of [11C]CO2, 3.9-5.3 GBq of [1-(11)C]EtI or 3.7-4.4 GBq of [2-(11)C]i-PrI was obtained with a specific activity of 37-99 GBq/micromol at EOS (n=3). This amount of radioactivity is sufficient for the synthesis of [11C]radioligands.
Collapse
Affiliation(s)
- Ming-Rong Zhang
- Department of Medical Imaging, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba 263-8555, Japan
| | | | | | | |
Collapse
|
9
|
Kimura Y, Ishii K, Fukumitsu N, Oda K, Sasaki T, Kawamura K, Ishiwata K. Quantitative analysis of adenosine A1 receptors in human brain using positron emission tomography and [1-methyl-11C]8-dicyclopropylmethyl-1-methyl-3-propylxanthine. Nucl Med Biol 2005; 31:975-81. [PMID: 15607479 DOI: 10.1016/j.nucmedbio.2004.06.005] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2004] [Revised: 04/23/2004] [Accepted: 06/28/2004] [Indexed: 11/17/2022]
Abstract
Fully quantitative analysis of the adenosine A(1) receptor (A1R) in the brain with (11)C-MPDX and positron emission tomography is reported. The kinetics is described using a two-tissue three-compartment model, and estimated binding potentials correspond well with the estimates made by Logan plot. The image of the binding potential of the MPDX is physiologically reasonable. We conclude that MPDX is applicable to the visualization of the A1Rs in the brain with Logan plot.
Collapse
Affiliation(s)
- Yuichi Kimura
- Positron Medical Center, Tokyo Metropolitan Institute of Gerontology, Itabashi, Tokyo 173-0022, Japan.
| | | | | | | | | | | | | |
Collapse
|
10
|
Ishiwata K, Nariai T, Kimura Y, Oda K, Kawamura K, Ishii K, Senda M, Wakabayashi S, Shimada J. Preclinical studies on [11C]MPDX for mapping adenosine A1 receptors by positron emission tomography. Ann Nucl Med 2002; 16:377-82. [PMID: 12416575 DOI: 10.1007/bf02990074] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
In previous in vivo studies with mice, rats and cats, we have demonstrated that [11C]MPDX ([1-methyl-11C]8-dicyclopropylmethyl-1-methyl-3-propylxanthine) is a potential radioligand for mapping adenosine A1 receptors of the brain by positron emission tomography (PET). In the present study, we performed a preclinical study. The radiation absorbed-dose by [11C]MPDX in humans estimated from the tissue distribution in mice was low enough for clinical use, and the acute toxicity and mutagenicity of MPDX were not found. The monkey brain was clearly visualized by PET with [11C]MPDX. We have concluded that [11C]MPDX is suitable for mapping adenosine A1 receptors in the human brain by PET.
Collapse
Affiliation(s)
- Kiichi Ishiwata
- Positron Medical Center, Tokyo Metropolitan Institute of Gerontology, Japan.
| | | | | | | | | | | | | | | | | |
Collapse
|
11
|
Shimada Y, Ishiwata K, Kiyosawa M, Nariai T, Oda K, Toyama H, Suzuki F, Ono K, Senda M. Mapping adenosine A(1) receptors in the cat brain by positron emission tomography with [(11)C]MPDX. Nucl Med Biol 2002; 29:29-37. [PMID: 11786273 DOI: 10.1016/s0969-8051(01)00265-7] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
We evaluated the potential of [(11)C]MPDX as a radioligand for mapping adenosine A(1) receptors in comparison with previously proposed [(11)C]KF15372 in cat brain by PET. Two tracers showed the same brain distribution. Brain uptake of [(11)C]MPDX (Ki = 4.2 nM) was much higher and washed out faster than that of [(11)C]KF15372 (Ki = 3.0 nM), and was blocked by carrier-loading or displaced with an A(1) antagonist. The regional A(1) receptor distribution evaluated with kinetic analysis is consistent with that previously measured in vitro. [(11)C]MPDX PET has a potential for mapping adenosine A(1) receptors in brain.
Collapse
Affiliation(s)
- Yuhei Shimada
- Positron Medical Center, Tokyo Metropolitan Institute of Gerontology, 1-1 Naka-cho, Itabashi-ku, Tokyo 172-0022, Tokyo, Japan
| | | | | | | | | | | | | | | | | |
Collapse
|
12
|
Ishiwata K, Shimada J, Wang WF, Harakawa H, Ishii S, Kiyosawa M, Suzuki F, Senda M. Evaluation of iodinated and brominated [11C]styrylxanthine derivatives as in vivo radioligands mapping adenosine A2A receptor in the central nervous system. Ann Nucl Med 2000; 14:247-53. [PMID: 11023024 DOI: 10.1007/bf02988206] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
In vivo assessment of the adenosine A2A receptors localized in the striatum by PET or SPECT offers us a new diagnostic tool for neurological disorders. In the present study, we evaluated the potential of iodinated and brominated styrylxanthine derivatives labeled with 11C as an in vivo probe. [7-Methyl-11C]-(E)-3,7-dimethyl-8-(3-iodostyryl)-1-propargylxan thine ([11C]IS-DMPX) and [7-methyl-11C]-(E)-8-(3-bromostyryl)-3,7-dimethyl-1-propargylxa nthine ([11C]BS-DMPX) were prepared by the 11C-methylation of corresponding 7-demethyl derivatives. An in vitro membrane binding study showed a high affinity (Ki values) of the two ligands for A2A receptor: 8.9 nM for IS-DMPX and 7.7 nM for BS-DMPX, and a high A2A/A1 selectivity: > 1100 for IS-DMPX and 300 for BS-DMPX. In mice, [11C]IS-DMPX and [11C]BS-DMPX were taken up slightly more in the striatum than in the reference regions such as the cortex and cerebellum. The uptake ratios of striatum to cortex and striatum to cerebellum gradually increased but were very small: 1.6-1.7 for the striatum-to-cortex ratio and 1.2 for the striatum-to-cerebellum ratio at 60 min postinjection. The uptake by these three regions was reduced by co-injection of an excess amount of carrier or an A2A antagonist KF17837, but not by an A1 antagonist KF15372. The blocking effects in the three regions were greater for [11C]BS-DMPX (32-57%) than for [11C]IS-DMPX (6-29%). Ex vivo autoradiography confirmed that the two ligands were slightly concentrated in the striatum. [11C]BS-DMPX showed more selective affinity for adenosine A2A receptors than [11C]IS-DMPX, but these results have shown that the two tracers were not suitable as in vivo ligands because of low selectivity for the striatal A2A receptors and a high nonspecific binding.
Collapse
Affiliation(s)
- K Ishiwata
- Positron Medical Center, Tokyo Metropolitan Institute of Gerontology, Japan.
| | | | | | | | | | | | | | | |
Collapse
|
13
|
Wakabayashi S, Nariai T, Ishiwata K, Nagaoka T, Hirakawa K, Oda K, Sakiyama Y, Shumiya S, Toyama H, Suzuki F, Senda M. A PET study of adenosine A1 receptor in anesthetized monkey brain. Nucl Med Biol 2000; 27:401-6. [PMID: 10938476 DOI: 10.1016/s0969-8051(00)00089-5] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
We demonstrated the distribution of adenosine A1 receptors in the anesthetized monkey brain with positron emission tomography (PET) using [(11)C]KF15372 ([1-propyl-(11)C]8-dicyclopropylmethyl-1, 3-dipropylxanthine). [(11)C]KF15372 was injected intravenously. The regional standardized uptake values and the distribution volume were calculated. We also investigated the effect of carrier on the uptake and regional brain distribution of [(11)C]KF15372. The use of [(11)C]KF15372 with dynamic PET scanning could be an appropriate method to analyze the regional binding potential of adenosine A1 receptors in living brain.
Collapse
Affiliation(s)
- S Wakabayashi
- Department of Neurosurgery, Tokyo Medical and Dental University, Tokyo, Japan
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
14
|
[11C]-labeling of some caffeine derivatives for mapping adenosine A2a receptors by PET technique. J Radioanal Nucl Chem 1999. [DOI: 10.1007/bf02345557] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
|
15
|
Márián T, Boros I, Lengyel Z, Balkay L, Horváth G, Emri M, Sarkadi E, Szentmiklósi AJ, Fekete I, Trón L. Preparation and primary evaluation of [11C]CSC as a possible tracer for mapping adenosine A2A receptors by PET. Appl Radiat Isot 1999; 50:887-93. [PMID: 10214707 DOI: 10.1016/s0969-8043(98)00162-6] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
A 11C labeled selective adenosine A2A antagonist, (E)-8-(3-chlorostyryl)-1,3-dimethyl-7-[11C]methylxanthine [11C]CSC) was prepared by the reaction of (E)-8-(3-chlorostyryl)-1,3-dimethylxanthine and [11C]methyl iodide. The decay-corrected radiochemical yield was 32.3% with a radiochemical purity of 99%, a specific activity of 1.85-5.55 GBq/mumol and a preparation time of 1 h. A primary evaluation of [11C]CSC as a potential tracer for mapping adenosine A2A receptors by positron emission tomography (PET) is also presented. Biodistribution and autoradiographic studies were carried out on Swiss mice and domestic rabbits. In mice the lung showed the highest uptake at 10 min after i.v. injection, followed by the liver, kidney, heart and brain. Inside the brain a high level of radioactivity accumulated in the striatum, in accordance with previous findings on the specific spatial distribution of A2A adenosine receptors and also in the medulla oblongata. Dynamic PET studies on rabbits showed a fast brain uptake of CSC, reaching a maximum in less then 2 min. On the basis of competition experiments with the unlabeled ligand [11C]CSC proves to bind specifically to the appropriate receptor.
Collapse
Affiliation(s)
- T Márián
- PET Centre, University Medical School of Debrecen, Hungary
| | | | | | | | | | | | | | | | | | | |
Collapse
|
16
|
Suzuki F, Ishiwata K. Selective adenosine antagonists for mapping central nervous system adenosine receptors with positron emission tomography: Carbon-11 labeled KF15372 (A1) and KF17837 (A2A). Drug Dev Res 1998. [DOI: 10.1002/(sici)1098-2299(199811/12)45:3/4<312::aid-ddr30>3.0.co;2-9] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
|
17
|
Ishiwata K, Noguchi J, Ishii S, Hatano K, Ito K, Nabeshima T, Senda M. Synthesis and preliminary evaluation of [11C]NE-100 labeled in two different positions as a PET sigma receptor ligand. Nucl Med Biol 1998; 25:195-202. [PMID: 9620623 DOI: 10.1016/s0969-8051(97)00170-4] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
N,N-Dipropyl-2-[4-methoxy-3-(2-phenylethoxy)phenyl]ethylamine (NE-100) was labeled with 11C in two different positions by the alkylation of an N-despropyl precursor with [11C]propyl iodide and of an O-desmethyl precursor with [11C]methyl iodide and was evaluated for the potential as a tracer for mapping sigma 1 receptors in the CNS and peripheral organs by PET. Following i.v. injection of [N-propyl-11C]NE-100 or [O-methyl-11C]NE-100 into mice, the two tracers showed similar tissue distribution patterns except for the liver and brain. With the coinjected carrier NE-100 or haloperidol, the uptake of [N-propyl-11C]NE-100 by the liver, pancreas and spleen was significantly decreased at 15 min after injection, whereas the effect was not significant for [O-methyl-11C]NE-100. The coinjection of NE-100 enhanced the brain uptake of the two tracers. Haloperidol also enhanced the brain uptake of [N-propyl-11C]NE-100, but not that of [O-methyl-11C]NE-100. The regional brain distribution assessed with [O-methyl-3H]NE-100 was consistent with the distribution pattern of the sigma receptors. Four sigma drugs reduced the regional brain uptake of [O-methyl-3H]NE-100 to 70%-90% of the control. In an ex vivo autoradiographic study of the rat brain, the uptake of [O-methyl-11C]NE-100 was blocked by carrier NE-100 or haloperidol (53%-59% of the control in the cortex), which suggests a receptor-specific distribution. These results show that [O-methyl-11C]NE-100 has limited potential as a PET ligand for mapping sigma 1 receptors in the peripheral organs and the CNS because of high nonspecific binding.
Collapse
Affiliation(s)
- K Ishiwata
- Positron Medical Center, Tokyo Metropolitan Institute of Gerontology, Itabashi, Japan.
| | | | | | | | | | | | | |
Collapse
|
18
|
Ishiwata K, Sakiyama Y, Sakiyama T, Shimada J, Toyama H, Oda K, Suzuki F, Senda M. Myocardial adenosine A2a receptor imaging of rabbit by PET with [11C]KF17837. Ann Nucl Med 1997; 11:219-25. [PMID: 9310171 DOI: 10.1007/bf03164767] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Adenosine A2a receptors are found in the endothelia, vascular smooth muscle cells and cardiac myocytes. The properties of a carbon-11 labeled A2a antagonist [11C]KF17837 ([7-methyl-11C](E)-8-(3,4-dimethoxystyryl)-1,3-dipropyl-7-methy lxa nthine) for myocardial imaging were evaluated by dynamic PET scanning of the myocardium in rabbits. Myocardial uptake of [11C]KF17837 was clearly visualized by PET. The tracer was taken up at a high level by the myocardium immediately after the injection, and the myocardial level of radioactivity gradually decreased. On the other hand, an inactive [11C]Z-isomer of [11C]KF17837 showed a very low myocardial uptake and the myocardium was not visualized with a selective A1 antagonist [11C]KF15372. By co-injection with carrier KF17837 or a xanthine type A2a antagonist 7-chlorostyrylcaffeine (CSC), the myocardial uptake of [11C]KF17837 was completely blocked. The effect of non-xanthine A2a antagonists ZM 241,385 and SCH 58,261, which have a higher affinity than CSC, was smaller than that of the CSC. The effect of weak antagonists caffeine and alloxazine or a xanthine type A1 antagonist KF15372 on the radioactivity level was small. It is concluded that PET with [11C]KF17837 can image myocardial adenosine A2a receptors.
Collapse
Affiliation(s)
- K Ishiwata
- Positron Medical Center, Tokyo Metropolitan Institute of Gerontology, Japan.
| | | | | | | | | | | | | | | |
Collapse
|
19
|
Stone-Elander S, Thorell JO, Eriksson L, Fredholm BB, Ingvar M. In vivo biodistribution of [N-11C-methyl]KF 17837 using 3-D-PET: evaluation as a ligand for the study of adenosine A2A receptors. Nucl Med Biol 1997; 24:187-91. [PMID: 9089711 DOI: 10.1016/s0969-8051(96)00216-8] [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: 02/04/2023]
Abstract
(KF 17837, (E)-8-(3,4-dimethoxystyryl)-1,3-dipropyl-7-methylxanthine, was 11C-labelled by methylation at N-7 of the nor-compound, KF 17440, using [11C]methyl iodide. Radiochemical conversions of 50% or 70-80% were obtained using sodium hydride or potassium carbonate, respectively, as base. Total synthesis time was 40-45 min, including isolation by semipreparative liquid chromatography. Cerebral uptake of [N-11C-methyl]KF 17837 in Cynomolgus monkeys, evaluated using positron emission tomography (PET), was so low that regional differences in distribution kinetics were revealed first after increasing injected dose 3-fold and using 3-D mode of data acquisition. At all times, the relative regional retention (maximum striatum:cerebellum: cortex approximately 1.1:1:0.8 at 20 min) was considerably different from the known relative density of A2A receptors in these regions. Radioactivity decreased more rapidly in the cortex than in the striatum and cerebellum (by 20% vs. 3-7%, respectively, between 5 and 50 min). Addition of carrier to [N-11C-methyl]KF 17837 only marginally affected the cerebral radiotracer uptake. By contrast, in the heart the initial tracer uptake was high and the elimination kinetics was enhanced by adding unlabelled carrier. We have thus shown that KF 17837 passes the blood-brain barrier, though to a very low extent. This fact and the apparently high nonspecific binding in vivo of [N-11C-methyl]KF 17837 in regions with low receptor densities limits its usefulness as a ligand for quantification of the adenosine A2A receptors in the primate brain.
Collapse
|
20
|
Noguchi J, Ishiwata K, Furuta R, Simada J, Kiyosawa M, Ishii S, Endo K, Suzuki F, Senda M. Evaluation of carbon-11 labeled KF15372 and its ethyl and methyl derivatives as a potential CNS adenosine A1 receptor ligand. Nucl Med Biol 1997; 24:53-9. [PMID: 9080475 DOI: 10.1016/s0969-8051(96)00161-8] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
We prepared [11C]KF15372 ([1-propyl-11C]8-dicyclopropylmethyl-1,3-dipropylxanthine, refs 10, 13) as well as its 11C-ethyl and 11C-methyl derivatives ([11C]EPDX and [11C]MPDX), and examined the potential of the three compounds as PET ligands for CNS adenosine A1 receptors. The three compounds had high affinity for the A1 receptors in vitro in the following order; [11C]EPDX > [11C]KF15372 > [11C]MPDX. In mice, the highest initial brain uptake was found in [11C]MPDX followed by [11C]EPDX and [11C]KF15372, but the level of [11C]MPDX decreased faster than those of the other two compounds. The uptake of each compound was decreased by carrier KF15372, but not by an A2A antagonist, indicating the selective affinity for the A1 receptors. Autoradiography with [11C]MPDX ex vivo demonstrated decreased A1 receptor binding in the superior colliculus of rats deprived of retino-collicular fibers by contralateral eye enucleation. These results show that three compounds have potential as PET ligands for CNS adenosine A1 receptors.
Collapse
Affiliation(s)
- J Noguchi
- Positron Medical Center, Tokyo Metropolitan Institute of Gerontology, Japan
| | | | | | | | | | | | | | | | | |
Collapse
|
21
|
Ishiwata K, Noguchi J, Toyama H, Sakiyama Y, Koike N, Ishii S, Oda K, Endo K, Suzuki F, Senda M. Synthesis and preliminary evaluation of [11C]KF17837, a selective adenosine A2A antagonist. Appl Radiat Isot 1996; 47:507-11. [PMID: 8673072 DOI: 10.1016/0969-8043(95)00295-2] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
An 11C-labeled selective adenosine A2A antagonist, (E)-8-(3,4-dimethoxystyryl)-1,3-dipropyl-7-[11C]-methylxanthine ([11C]KF17837), was prepared by reaction of (E)-8-(3,4-dimethoxystyryl)-1,3-dipropylxanthine and [11C]methyl iodide with decay-corrected radiochemical yield of 19-50%, radiochemical purity of > 99%, sp. act. of 17-100 GBq/mumol and preparation time of 20-25 min. In mice, the myocardium showed the highest (13.4% ID/g) at 5 min after i.v. injection, which decreased gradually with time. The specific myocardial uptake was visualized by gamma-camera. In the brain region the radioactivity level was higher in the A2A receptors-rich striatum than in the cortex and cerebellum. The specific striatal uptake in rats was clearly demonstrated by PET. These results have shown that [11C]KF17837 is a potential PET radioligand for mapping the adenosine A2A receptors in the heart and brain.
Collapse
Affiliation(s)
- K Ishiwata
- Positron Medical Center, Tokyo Metropolitan Institute of Gerontology, Itabashi, Tokyo
| | | | | | | | | | | | | | | | | | | |
Collapse
|