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Fuchigami T, Haradahira T, Fujimoto N, Nojiri Y, Mukai T, Yamamoto F, Okauchi T, Maeda J, Suzuki K, Suhara T, Yamaguchi H, Ogawa M, Magata Y, Maeda M. Development of N-[11C]methylamino 4-hydroxy-2(1H)-quinolone derivatives as PET radioligands for the glycine-binding site of NMDA receptors. Bioorg Med Chem 2009; 17:5665-75. [DOI: 10.1016/j.bmc.2009.06.014] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2009] [Revised: 06/04/2009] [Accepted: 06/06/2009] [Indexed: 10/20/2022]
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Difference in brain distributions of carbon 11-labeled 4-hydroxy-2(1H)-quinolones as PET radioligands for the glycine-binding site of the NMDA ion channel. Nucl Med Biol 2008; 35:203-12. [DOI: 10.1016/j.nucmedbio.2007.10.007] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2006] [Revised: 10/02/2007] [Accepted: 10/17/2007] [Indexed: 10/22/2022]
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Matsumoto R, Haradahira T, Ito H, Fujimura Y, Seki C, Ikoma Y, Maeda J, Arakawa R, Takano A, Takahashi H, Higuchi M, Suzuki K, Fukui K, Suhara T. Measurement of glycine binding site ofN-methyl-d-asparate receptors in living human brain using 4-acetoxy derivative of L-703,717, 4-acetoxy-7-chloro-3-[3-(4-[11c] methoxybenzyl) phenyl]-2(1H)-quinolone (AcL703) with positron emission tomography. Synapse 2007; 61:795-800. [PMID: 17598152 DOI: 10.1002/syn.20415] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
N-methyl-D-aspartate (NMDA) receptors are of major interest in brain functions and neuropsychiatric disorders. However, at present there are few suitable radioligands for in vivo imaging of NMDA receptors. 7-choloro-4-hydroxy-3-[3-(4-methoxybenzyl) phenyl]-2(1H)-quinolone (L-703,717) is one of the potent ligands for the glycine-binding site of NMDA receptors. 4-Acetoxy derivative of L-703,717 (AcL703) is a candidate, as a positron emission tomography (PET) ligand for NMDA receptors, because of its better permeability at the blood-brain barrier compared with L-703,717. After intravenous injection of 624-851 MBq of [11C]AcL703, dynamic PET scan was performed on six healthy males for 90 min. Regions-of-interest were located on the cerebral cortices, cerebellar cortex, and cerebral white matter. The binding potential (BP) was calculated from the ratio of the area under the curve (AUC) of radioactivities from 40 to 90 min in the target region to that in white matter. Regional radioactivities reached close to equilibrium in all regions after about 40 min postinjection. Regional brain uptake of [11C]AcL703 at 40 min after injection was 0.00028-0.00065% of the injected dose/milliliter. Radioactivity concentration of [11C]AcL703 was highest in the cerebellar cortex and lowest in white matter. AUC in the cerebellar cortex was higher than those of cerebral cortices, thalamus, striatum, and white matter. BP in the cerebellar cortex was twofold higher than in the cerebral cortices (cerebellar cortex: BP=2.20+/-0.72; cerebral cortices: BP=1.05+/-0.45). Despite the low brain uptake of [11C]AcL703, regional distributions were in good agreement with our previous studies of rodents. This indicates the possibility of in vivo evaluation of NMDA receptors using PET with [11C]AcL703 in living human brain.
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Affiliation(s)
- Ryohei Matsumoto
- Department of Molecular Neuroimaging, Molecular Imaging Center, National Institute of Radiological Sciences, Chiba, Japan
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Haradahira T, Okauchi T, Maeda J, Zhang MR, Nishikawa T, Konno R, Suzuki K, Suhara T. Effects of endogenous agonists, glycine and D-serine, on in vivo specific binding of [11C]L-703,717, a PET radioligand for the glycine-binding site of NMDA receptors. Synapse 2003; 50:130-6. [PMID: 12923815 DOI: 10.1002/syn.10254] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
A positron-emitter (carbon-11) labeled antagonist for the glycine-binding site of NMDA receptors, [(11)C]L-703,717, has a unique in vivo binding characteristic, in which it preferentially binds to cerebellar-specific NMDA receptors consisting of a GluRepsilon3 subunit and eventually accumulates in rodent cerebellum under in vivo conditions, but not under in vitro conditions. In order to understand the in vivo-specific site and subunit localization of this radioligand, we examined the effect of the endogenous glycine site agonists, glycine and D-serine, on in vivo [(11)C]L-703,717 binding. An increase in extracellular glycine concentration by treatment with a glycine transporter 1 (GlyT1)-selective inhibitor, NFPS ethyl ester, significantly decreased the cerebellar localization of [(11)C]L-703,717 in rats. D-serine is known to be concentrated in mammalian forebrain regions. The lack of D-serine detection in the cerebellum may be due to the fact that it has the highest enzymatic activity of D-amino acid oxidase (DAO). It was found that the cerebellar localization of [(11)C]L-703,717 is greatly diminished in mutant mice lacking DAO, in which D-serine content in the cerebellum is drastically increased from a nondetectable level in normal mice. These studies indicate that [(11)C]L-703,717 is susceptible to inhibition by glycine site agonists in its in vivo binding, and suggest that regional differences in inhibitions by endogenous agonists may be a crucial factor in the site- and subunit-specific binding of this glycine-site antagonist.
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Affiliation(s)
- Terushi Haradahira
- Department of Medical Imaging, National Institute of Radiological Sciences, Inage-ku, Chiba 263-8555, Japan.
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Piel M, Schirrmacher R, Höhnemann S, Hamkens W, Kohl B, Jansen M, Schmitt U, Lüddens H, Dannhardt G, Rösch F. Synthesis and evaluation of 5,7-dichloro-4-(3-{4-[4-(2-[18F]fluoroethyl)-piperazin-1-yl]-phenyl}-ureido)-1,2,3,4-tetrahydroquinoline-2-carboxylic acid as a potential NMDA ligand to study glutamatergic neurotransmission in vivo. J Labelled Comp Radiopharm 2003. [DOI: 10.1002/jlcr.682] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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Waterhouse RN, Sultana A, Laruelle M. In vivo evaluation of [11C]-3-[2-[(3-methoxyphenylamino)carbonyl]ethenyl]-4,6-dichloroindole-2-carboxylic acid ([11C]3MPICA) as a PET radiotracer for the glycine site of the NMDA ion channel. Nucl Med Biol 2002; 29:791-4. [PMID: 12453587 DOI: 10.1016/s0969-8051(02)00335-9] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Alterations in normal NMDA receptor composition, densities and function have been implicated in the pathophysiology of certain neurological and neuropsychiatric disorders such as Parkinson's Disease, Huntington's Chorea, schizophrenia, alcoholism and stroke. In our first effort to provide PET ligands for the NMDA/glycine site, we reported the synthesis of a novel high affinity glycine site ligand, 3-[2-[(3-methoxyphenylamino)carbonyl]ethenyl]-4,6-dichloroindole-2-carboxylic acid ((3MPICA), Ki = 4.8 +/- 0.9 nM) and the corresponding carbon-11 labeled PET ligand, [11C]3MPICA. We report here the in vivo evaluation of [11C]3MPICA in rats. Biodistribution analysis revealed that [11C]3MPICA exhibited low degree of brain penetration and high blood concentration. The average uptake at two minutes was highest in the cerebellum (0.19 +/- 0.04 %ID/g) and thalamus (0.18 +/- 0.05 %ID/g) and lower in the hippocampus (0.13 +/- 0.03) and frontal cortex (0.11 +/- 0.04 %ID/g). The radioactivity cleared quickly from all brain regions examined. Administration of unlabeled 3MPICA (1 mg/kg, i.v.) revealed at 60 minutes a small general reduction in regional brain radioactivity concentrations in treated animals versus controls, however, the blood radioactivity concentration was also lowered, confounding the assessment of the degree of saturable binding. Warfarin co-administration (100 mg/kg, i.v.) significantly lowered blood activity at 5 minutes post-injection (-27%, P < 0.01) but failed to significantly increase the brain uptake of the radiotracer. In view of these results, and especially considering the low brain penetration of this tracer, [11C]3MPICA does not appear to be a promising PET radiotracer for in vivo use.
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Affiliation(s)
- Rikki N Waterhouse
- Department of Psychiatry, Columbia University College of Physicians and Surgeons and the New York State Psychiatric Institute, New York, NY 10032, USA.
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Waterhouse RN, Sultana A, Guo N, Lee B, Simpson N, Collier L, Laruelle M. Synthesis and characterization of 4,6-dichloroindole-based radioligands for imaging the glycine site of the NMDA ion channel. J Labelled Comp Radiopharm 2002. [DOI: 10.1002/jlcr.528] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Haradahira T, Zhang MR, Maeda J, Okauchi T, Kida T, Kawabe K, Sasaki S, Suhara T, Suzuki K. A prodrug of NMDA/glycine site antagonist, L-703,717, with improved BBB permeability: 4-acetoxy derivative and its positron-emitter labeled analog. Chem Pharm Bull (Tokyo) 2001; 49:147-50. [PMID: 11217099 DOI: 10.1248/cpb.49.147] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
4-Acetoxy derivative (1) of L-703,717, a high-affinity (IC50=4.5 nM) antagonist for the glycine site of NMDA receptors, was synthesized and its brain uptake was examined using a carbon-11 labeled analog ([11C]1). Initial radioactivity in the brain after intravenous injection of [11C]1 was a 2-fold that of [11C]L-703,717 in mice. Rapid bioconversion of [11C]1 into [11C]L-703,717 was demonstrated by metabolite analyses of rat brain after [11C]1 injection. Ex vivo autoradiography of [11C]1 in rat brain showed the same cerebellar localization of radioactivity as [11C]L-703,717. These results indicate that 1 is a promising pharmacological tool as a prodrug of L-703,717 with improved BBB permeability.
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Affiliation(s)
- T Haradahira
- Division of Advanced Technology for Medical Imaging, National Institute of Radiological Sciences, Chiba, Japan.
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Haradahira T, Zhang M, Maeda J, Okauchi T, Kawabe K, Kida T, Suzuki K, Suhara1 T. A strategy for increasing the brain uptake of a radioligand in animals: use of a drug that inhibits plasma protein binding. Nucl Med Biol 2000; 27:357-60. [PMID: 10938470 DOI: 10.1016/s0969-8051(00)00096-2] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
A positron-emitter labeled radioligand for the glycine-binding site of the N-methyl-D-aspartate (NMDA) receptor, [(11)C]L-703,717, was examined for its ability to penetrate the brain in animals by simultaneous use with drugs having high-affinity separate binding sites on human serum albumin. [(11)C]L-703,717 has poor blood-brain barrier (BBB) permeability because it binds tightly to plasma proteins. Co-injection of warfarin (50-200 mg/kg), a drug that binds to albumin and resembles L-703,717 in structure, dose-dependently enhanced the penetration by [(11)C]L-703,717 in mice, resulting in a five-fold increase in the brain radioactivity at 1 min after the injection. Drugs structurally unrelated to L-703,717, salicylate, phenol red, and L-tryptophan, were less effective or ineffective in increasing the uptake of [(11)C]L-703,717. These results suggest that the simultaneous use of a drug that inhibits the binding of a radioligand to plasma proteins is a useful way to overcome the poor BBB permeability of the radioligand triggered by its tight binding to plasma proteins. In brain distribution studies in rodents, it was found that, after the increase in brain uptake with warfarin, much of the glycine site antagonist accumulates in the cerebellum but its pharmacological specificity did not match the glycine site of NMDA receptors.
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Affiliation(s)
- T Haradahira
- Division of Advanced Technology for Medical Imaging, National Institute of Radiological Sciences, Chiba, Japan.
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