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Haveman LYF, Vugts DJ, Windhorst AD. State of the art procedures towards reactive [ 18F]fluoride in PET tracer synthesis. EJNMMI Radiopharm Chem 2023; 8:28. [PMID: 37824021 PMCID: PMC10570257 DOI: 10.1186/s41181-023-00203-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2023] [Accepted: 08/03/2023] [Indexed: 10/13/2023] Open
Abstract
BACKGROUND Positron emission tomography (PET) is a powerful, non-invasive preclinical and clinical nuclear imaging technique used in disease diagnosis and therapy assessment. Fluorine-18 is the predominant radionuclide used for PET tracer synthesis. An impressive variety of new 'late-stage' radiolabeling methodologies for the preparation of 18F-labeled tracers has appeared in order to improve the efficiency of the labeling reaction. MAIN BODY Despite these developments, one outstanding challenge into the early key steps of the process remains: the preparation of reactive [18F]fluoride from oxygen-18 enriched water ([18O]H2O). In the last decade, significant changes into the trapping, elution and drying stages have been introduced. This review provides an overview of the strategies and recent developments in the production of reactive [18F]fluoride and its use for radiolabeling. CONCLUSION Improved, modified or even completely new fluorine-18 work-up procedures have been developed in the last decade with widespread use in base-sensitive nucleophilic 18F-fluorination reactions. The many promising developments may lead to a few standardized drying methodologies for the routine production of a broad scale of PET tracers.
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Affiliation(s)
- Lizeth Y F Haveman
- Radiology and Nuclear Medicine, Amsterdam UMC, Vrije Universiteit Amsterdam, De Boelelaan 1117, Amsterdam, The Netherlands
- Chemistry and Pharmaceutical Sciences, Amsterdam Institute of Molecular and Life Sciences (AIMMS), Amsterdam, The Netherlands
| | - Danielle J Vugts
- Radiology and Nuclear Medicine, Amsterdam UMC, Vrije Universiteit Amsterdam, De Boelelaan 1117, Amsterdam, The Netherlands
- Cancer Center Amsterdam (CCA), Amsterdam, The Netherlands
| | - Albert D Windhorst
- Radiology and Nuclear Medicine, Amsterdam UMC, Vrije Universiteit Amsterdam, De Boelelaan 1117, Amsterdam, The Netherlands.
- Neuroscience Amsterdam, Amsterdam, The Netherlands.
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2
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Affiliation(s)
- Christopher L. Cioffi
- Departments of Basic and Clinical Sciences and Pharmaceutical Sciences, Albany College of Pharmacy and Health Sciences , Albany, NY, USA
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3
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Cioffi CL, Liu S, Wolf MA, Guzzo PR, Sadalapure K, Parthasarathy V, Loong DTJ, Maeng JH, Carulli E, Fang X, Karunakaran K, Matta L, Choo SH, Panduga S, Buckle RN, Davis RN, Sakwa SA, Gupta P, Sargent BJ, Moore NA, Luche MM, Carr GJ, Khmelnitsky YL, Ismail J, Chung M, Bai M, Leong WY, Sachdev N, Swaminathan S, Mhyre AJ. Synthesis and Biological Evaluation of N-((1-(4-(Sulfonyl)piperazin-1-yl)cycloalkyl)methyl)benzamide Inhibitors of Glycine Transporter-1. J Med Chem 2016; 59:8473-94. [PMID: 27559615 DOI: 10.1021/acs.jmedchem.6b00914] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
We previously disclosed the discovery of rationally designed N-((1-(4-(propylsulfonyl)piperazin-1-yl)cycloalkyl)methyl)benzamide inhibitors of glycine transporter-1 (GlyT-1), represented by analogues 10 and 11. We describe herein further structure-activity relationship exploration of this series via an optimization strategy that primarily focused on the sulfonamide and benzamide appendages of the scaffold. These efforts led to the identification of advanced leads possessing a desirable balance of excellent in vitro GlyT-1 potency and selectivity, favorable ADME and in vitro pharmacological profiles, and suitable pharmacokinetic and safety characteristics. Representative analogue (+)-67 exhibited robust in vivo activity in the cerebral spinal fluid glycine biomarker model in both rodents and nonhuman primates. Furthermore, rodent microdialysis experiments also demonstrated that oral administration of (+)-67 significantly elevated extracellular glycine levels within the medial prefrontal cortex (mPFC).
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Affiliation(s)
- Christopher L Cioffi
- Department of Medicinal Chemistry, AMRI , East Campus, 3 University Place, Rensselaer, New York 12144, United States
| | - Shuang Liu
- Department of Medicinal Chemistry, AMRI , East Campus, 3 University Place, Rensselaer, New York 12144, United States
| | - Mark A Wolf
- Department of Medicinal Chemistry, AMRI , East Campus, 3 University Place, Rensselaer, New York 12144, United States
| | - Peter R Guzzo
- Department of Medicinal Chemistry, AMRI , East Campus, 3 University Place, Rensselaer, New York 12144, United States
| | - Kashinath Sadalapure
- Discovery Research and Development Chemistry, Singapore Research Center, AMRI , 61 Science Park Road, Science Park III, 117525, Singapore
| | - Visweswaran Parthasarathy
- Discovery Research and Development Chemistry, Singapore Research Center, AMRI , 61 Science Park Road, Science Park III, 117525, Singapore
| | - David T J Loong
- Discovery Research and Development Chemistry, Singapore Research Center, AMRI , 61 Science Park Road, Science Park III, 117525, Singapore
| | - Jun-Ho Maeng
- Discovery Research and Development Chemistry, Singapore Research Center, AMRI , 61 Science Park Road, Science Park III, 117525, Singapore
| | - Edmund Carulli
- Discovery Research and Development Chemistry, Singapore Research Center, AMRI , 61 Science Park Road, Science Park III, 117525, Singapore
| | - Xiao Fang
- Discovery Research and Development Chemistry, Singapore Research Center, AMRI , 61 Science Park Road, Science Park III, 117525, Singapore
| | - Kalesh Karunakaran
- Discovery Research and Development Chemistry, Singapore Research Center, AMRI , 61 Science Park Road, Science Park III, 117525, Singapore
| | - Lakshman Matta
- Discovery Research and Development Chemistry, Singapore Research Center, AMRI , 61 Science Park Road, Science Park III, 117525, Singapore
| | - Sok Hui Choo
- Discovery Research and Development Chemistry, Singapore Research Center, AMRI , 61 Science Park Road, Science Park III, 117525, Singapore
| | - Shailijia Panduga
- Discovery Research and Development Chemistry, Singapore Research Center, AMRI , 61 Science Park Road, Science Park III, 117525, Singapore
| | - Ronald N Buckle
- Department of Medicinal Chemistry, AMRI , East Campus, 3 University Place, Rensselaer, New York 12144, United States
| | - Randall N Davis
- Department of Medicinal Chemistry, AMRI , East Campus, 3 University Place, Rensselaer, New York 12144, United States
| | - Samuel A Sakwa
- Department of Medicinal Chemistry, AMRI , East Campus, 3 University Place, Rensselaer, New York 12144, United States
| | - Priya Gupta
- Discovery Research and Development Chemistry, Singapore Research Center, AMRI , 61 Science Park Road, Science Park III, 117525, Singapore
| | - Bruce J Sargent
- Department of Medicinal Chemistry, AMRI , East Campus, 3 University Place, Rensselaer, New York 12144, United States
| | - Nicholas A Moore
- Department of Medicinal Chemistry, AMRI , East Campus, 3 University Place, Rensselaer, New York 12144, United States
| | - Michele M Luche
- Bothell Research Center, AMRI , 22215 26th Ave SE, Bothell, Washington 98021-4425, United States
| | - Grant J Carr
- Bothell Research Center, AMRI , 22215 26th Ave SE, Bothell, Washington 98021-4425, United States
| | - Yuri L Khmelnitsky
- Drug Metabolism and Pharmacokinetics, AMRI , East Campus, 17 University Place, Rensselaer, New York 12144, United States
| | - Jiffry Ismail
- Drug Metabolism and Pharmacokinetics, AMRI , East Campus, 17 University Place, Rensselaer, New York 12144, United States
| | - Mark Chung
- Discovery Research and Development Chemistry, Singapore Research Center, AMRI , 61 Science Park Road, Science Park III, 117525, Singapore
| | - Mei Bai
- Discovery Research and Development Chemistry, Singapore Research Center, AMRI , 61 Science Park Road, Science Park III, 117525, Singapore
| | - Wei Yee Leong
- Discovery Research and Development Chemistry, Singapore Research Center, AMRI , 61 Science Park Road, Science Park III, 117525, Singapore
| | - Nidhi Sachdev
- Discovery Research and Development Chemistry, Singapore Research Center, AMRI , 61 Science Park Road, Science Park III, 117525, Singapore
| | - Srividya Swaminathan
- Discovery Research and Development Chemistry, Singapore Research Center, AMRI , 61 Science Park Road, Science Park III, 117525, Singapore
| | - Andrew J Mhyre
- Bothell Research Center, AMRI , 22215 26th Ave SE, Bothell, Washington 98021-4425, United States
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4
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Zheng MQ, Lin SF, Holden D, Naganawa M, Ropchan JR, Najafzaden S, Kapinos M, Tabriz M, Carson RE, Hamill TG, Huang Y. Comparative evaluation of two glycine transporter 1 radiotracers [11C]GSK931145 and [18F]MK-6577 in baboons. Synapse 2015; 70:112-20. [PMID: 26671330 DOI: 10.1002/syn.21879] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2015] [Revised: 12/02/2015] [Accepted: 12/11/2015] [Indexed: 01/24/2023]
Abstract
Glycine transporter type-1 (GlyT1) has been proposed as a target for drug development for schizophrenia. PET imaging with a GlyT1 specific radiotracer will allow for the measurement of target occupancy of GlyT1 inhibitors, and for in vivo investigation of GlyT1 alterations in schizophrenia. We conducted a comparative evaluation of two GlyT1 radiotracers, [(11) C]GSK931145, and [(18) F]MK-6577, in baboons. Two baboons were imaged with [(11) C]GSK931145 and [(18) F]MK-6577. Blocking studies with GSK931145 (0.3 or 0.2 mg/kg) were conducted to determine the level of tracer specific binding. [(11) C]GSK931145 and [(18) F]MK-6577 were synthesized in good yield and high specific activity. Moderately fast metabolism was observed for both tracers, with ∼ 30% of parent at 30 min post-injection. In the brain, both radiotracers showed good uptake and distribution profiles consistent with regional GlyT1 densities. [(18) F]MK-6577 displayed higher uptake and faster kinetics than [(11) C]GSK931145. Time activity curves were well described by the two-tissue compartment model. Regional volume of distribution (VT ) values were higher for [(18) F]MK-6577 than [(11) C]GSK931145. Pretreatment with GSK931145 reduced tracer uptake to a homogeneous level throughout the brain, indicating in vivo binding specificity and lack of a reference region for both radiotracers. Linear regression analysis of VT estimates between tracers indicated higher specific binding for [(18) F]MK-6577 than [(11) C]GSK931145, consistent with higher regional binding potential (BPND ) values of [(18) F]MK-6577 calculated using VT from the baseline scans and non-displaceable distribution volume (VND ) derived from blocking studies. [(18) F]MK-6577 appears to be a superior radiotracer with higher brain uptake, faster kinetics, and higher specific binding signals than [(11) C]GSK931145.
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Affiliation(s)
- Ming-Qiang Zheng
- Department of Radiology and Biomedical Imaging, Yale University School of Medicine, PET Center, New Haven, Connecticut
| | - Shu-Fei Lin
- Department of Radiology and Biomedical Imaging, Yale University School of Medicine, PET Center, New Haven, Connecticut
| | - Daniel Holden
- Department of Radiology and Biomedical Imaging, Yale University School of Medicine, PET Center, New Haven, Connecticut
| | - Mika Naganawa
- Department of Radiology and Biomedical Imaging, Yale University School of Medicine, PET Center, New Haven, Connecticut
| | - Jim R Ropchan
- Department of Radiology and Biomedical Imaging, Yale University School of Medicine, PET Center, New Haven, Connecticut
| | - Soheila Najafzaden
- Department of Radiology and Biomedical Imaging, Yale University School of Medicine, PET Center, New Haven, Connecticut
| | - Michael Kapinos
- Department of Radiology and Biomedical Imaging, Yale University School of Medicine, PET Center, New Haven, Connecticut
| | - Mike Tabriz
- Department of Radiology and Biomedical Imaging, Yale University School of Medicine, PET Center, New Haven, Connecticut
| | - Richard E Carson
- Department of Radiology and Biomedical Imaging, Yale University School of Medicine, PET Center, New Haven, Connecticut
| | - Terence G Hamill
- Discovery Imaging, Merck Research Laboratories, West Point, Pennsylvania
| | - Yiyun Huang
- Department of Radiology and Biomedical Imaging, Yale University School of Medicine, PET Center, New Haven, Connecticut
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5
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Measurement of Bmax and Kd with the glycine transporter 1 radiotracer ¹⁸F-MK6577 using a novel multi-infusion paradigm. J Cereb Blood Flow Metab 2015. [PMID: 26198176 PMCID: PMC4671121 DOI: 10.1038/jcbfm.2015.163] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Glycine is a co-agonist of glutamate at the NMDA receptor. Glycine transporter 1 (GlyT1) inhibitors are reported to be potential therapeutic agents for schizophrenia. (18)F-MK6577 is a new positron emission tomography (PET) radiotracer useful for imaging brain GlyT1 and its occupancy in humans. We devised a novel multi-infusion paradigm of radiolabeled and unlabeled compound and an iterative linear/nonlinear alternating fitting method to allow for the determination of in vivo affinity (Kd) and target concentration (Bmax) images, constraining Kd to be uniform across the brain. This paradigm was tested with (18)F-MK6577 in baboons. Voxel-based analysis produced high quality Bmax images and reliable Kd estimates, and also suggested that the nondisplaceable distribution volume (VND) is not uniform throughout the brain. In vivo GlyT1 Kd was estimated to be 1.87 nmol/L for (18)F-MK6577, and the rank order of GlyT1 distribution measured in the baboon brain was: high in the brainstem (133 nmol/L), medium in the cerebellum (83 nmol/L), and low in the cortex (30 nmol/L). These in vivo Kd and Bmax values agreed well with those determined in vitro, thus validating our novel multi-infusion approach.
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6
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Castner SA, Murthy NV, Ridler K, Herdon H, Roberts BM, Weinzimmer DP, Huang Y, Zheng MQ, Rabiner EA, Gunn RN, Carson RE, Williams GV, Laruelle M. Relationship between glycine transporter 1 inhibition as measured with positron emission tomography and changes in cognitive performances in nonhuman primates. Neuropsychopharmacology 2014; 39:2742-9. [PMID: 24487737 PMCID: PMC4200505 DOI: 10.1038/npp.2014.4] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/27/2012] [Revised: 11/04/2013] [Accepted: 12/13/2013] [Indexed: 01/22/2023]
Abstract
Several lines of evidence suggest that schizophrenia is associated with deficits in glutamatergic transmission at the N-methyl-d-aspartate (NMDA) receptors. Glycine is a NMDA receptor co-agonist, and extracellular levels of glycine are regulated in the forebrain by the glycine type-1 transporters (GlyT-1). GlyT-1 inhibitors elevate extracellular glycine and thus potentiate NMDA transmission. This mechanism represents a promising new avenue for the treatment of schizophrenia. Here, the recently introduced positron emission tomography radiotracer [11C]GSK931145 was used to quantify the relationship between occupancy of GlyT-1 by a GlyT-1 inhibitor, Org 25935, and its impact on spatial working memory performances in rhesus monkeys. The effect of Org 25935 on working memory was assessed both in control conditions and during a state of relative NMDA hypofunction induced by ketamine administration, at a dose selected for each animal to reduce task performance by about 50%. Under control conditions, Org 25935 had no effect on working memory at GlyT-1 occupancies lower than 75% and significantly impaired working memory at occupancies higher than 75%. Under ketamine conditions, Org 25935 reversed the deficit in working memory induced by ketamine and did so optimally in the 40-70% GlyT-1 occupancy range. The results confirm the efficacy of this mechanism to correct working memory deficits associated with NMDA hypofunction. These data also suggest the existence of an inverted-U dose-response curve in the potential therapeutic effect of this class of compounds.
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Affiliation(s)
- S A Castner
- Department of Psychiatry, Yale University School of Medicine, New Haven, CT, USA
| | - N V Murthy
- Neurosciences Centre for Excellence in Drug Discovery, GlaxoSmithKline, Harlow, UK
| | - K Ridler
- Clinical Imaging Centre, GlaxoSmithKline, Hammersmith Hospital–Imperial College, London, UK
| | - H Herdon
- Neurosciences Centre for Excellence in Drug Discovery, GlaxoSmithKline, Harlow, UK
| | - B M Roberts
- Department of Psychiatry, Yale University School of Medicine, New Haven, CT, USA
| | - D P Weinzimmer
- Department of Radiology, Yale University School of Medicine, New Haven, CT, USA
| | - Y Huang
- Department of Radiology, Yale University School of Medicine, New Haven, CT, USA
| | - M Q Zheng
- Department of Radiology, Yale University School of Medicine, New Haven, CT, USA
| | - E A Rabiner
- Clinical Imaging Centre, GlaxoSmithKline, Hammersmith Hospital–Imperial College, London, UK
| | - R N Gunn
- Clinical Imaging Centre, GlaxoSmithKline, Hammersmith Hospital–Imperial College, London, UK
| | - R E Carson
- Department of Radiology, Yale University School of Medicine, New Haven, CT, USA
| | - G V Williams
- Department of Psychiatry, Yale University School of Medicine, New Haven, CT, USA
| | - M Laruelle
- Department of Psychiatry, Yale University School of Medicine, New Haven, CT, USA,Neurosciences Centre for Excellence in Drug Discovery, GlaxoSmithKline, Harlow, UK,Department of Radiology, Yale University School of Medicine, New Haven, CT, USA,UCB Pharma, Braine-l'Alleud, Brussels, Belgium,UCB Pharma, Chemin du Foriest, Braine-l'Alleud 1420, Belgium, Tel: +1 914 316 0923, Fax: +322 386 2550, E-mail:
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7
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Joshi AD, Sanabria-Bohórquez SM, Bormans G, Koole M, De Hoon J, Van Hecken A, Depre M, De Lepeleire I, Van Laere K, Sur C, Hamill TG. Characterization of the novel GlyT1 PET tracer [18F]MK-6577 in humans. Synapse 2014; 69:33-40. [PMID: 25196464 DOI: 10.1002/syn.21782] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2014] [Revised: 07/06/2014] [Accepted: 07/26/2014] [Indexed: 01/05/2023]
Abstract
Decreased glutamatergic neurotransmission is hypothesized to be involved in the pathophysiology of schizophrenia. Inhibition of glycine transporter Type-1 (GlyT1) reuptake is expected to increase the glutamatergic neurotransmission and may serve as treatment for cognitive and negative symptoms of schizophrenia. In this article, we present human data from a novel GlyT1 PET tracer, [(18) F]MK-6577. In the process of developing a GlyT1 inhibitor therapeutic, a PET tracer can assist in determining the dose with a high probability of sufficiently testing the mechanism of action. This article reports the human PET studies with [(18) F]MK-6577 for measuring GlyT1 receptor availability at baseline in normal human subjects and occupancy with a GlyT1 inhibitor, MK-2637. Studies were also performed to measure radiation burden and the baseline test-retest (T-RT) variability of the tracer. The effective dose from sequential whole-body dosimetry scans in three male subjects was estimated to be 24.5 ± 2.9 µSV/MBq (mean ± SD). The time-activity curves from T-RT scans modeled satisfactorily using a two tissue compartmental model. The tracer uptake was highest in the pons (VT = 6.7 ± 0.9, BPND = 4.1 ± 0.43) and lowest in the cortex (VT = 2.1 ± 0.5, BPND = 0.60 ± 0.23). VT T-RT variability measured in three subjects was <12% on average. The occupancy scans performed in a cohort of 15 subjects indicated absence of a reference region. The in vivo potency (Occ50 ) of MK-2637 was determined using two methods: A: Lassen plot with a population input function (Occ50 = 106 nM, SE = 20 nM) and B: pseudo reference tissue model using cortex as the pseudo reference region (Occ50 = 141 nM, SE = 21 nM).
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8
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Piel M, Vernaleken I, Rösch F. Positron Emission Tomography in CNS Drug Discovery and Drug Monitoring. J Med Chem 2014; 57:9232-58. [DOI: 10.1021/jm5001858] [Citation(s) in RCA: 111] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Affiliation(s)
- Markus Piel
- Institute
of Nuclear Chemistry, Johannes Gutenberg-University, Fritz-Strassmann-Weg 2, D-55128 Mainz, Germany
| | - Ingo Vernaleken
- Department
of Psychiatry, Psychotherapy, and Psychosomatics, RWTH Aachen University, Pauwelsstraße 30, D-52074 Aachen, Germany
| | - Frank Rösch
- Institute
of Nuclear Chemistry, Johannes Gutenberg-University, Fritz-Strassmann-Weg 2, D-55128 Mainz, Germany
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9
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Ermert J. 18F-labelled intermediates for radiosynthesis by modular build-up reactions: newer developments. BIOMED RESEARCH INTERNATIONAL 2014; 2014:812973. [PMID: 25343144 PMCID: PMC4197889 DOI: 10.1155/2014/812973] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/27/2014] [Accepted: 05/12/2014] [Indexed: 12/20/2022]
Abstract
This brief review gives an overview of newer developments in (18)F-chemistry with the focus on small (18)F-labelled molecules as intermediates for modular build-up syntheses. The short half-life (<2 h) of the radionuclide requires efficient syntheses of these intermediates considering that multistep syntheses are often time consuming and characterized by a loss of yield in each reaction step. Recent examples of improved synthesis of (18)F-labelled intermediates show new possibilities for no-carrier-added ring-fluorinated arenes, novel intermediates for tri[(18)F]fluoromethylation reactions, and (18)F-fluorovinylation methods.
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Affiliation(s)
- Johannes Ermert
- Institut für Neurowissenschaften und Medizin, INM-5: Nuklearchemie, Forschungszentrum Jülich, 52425 Jülich, Germany
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10
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Novel GlyT1 inhibitor chemotypes by scaffold hopping. Part 1: development of a potent and CNS penetrant [3.1.0]-based lead. Bioorg Med Chem Lett 2014; 24:1067-70. [PMID: 24461352 DOI: 10.1016/j.bmcl.2014.01.013] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2013] [Revised: 01/02/2014] [Accepted: 01/06/2014] [Indexed: 01/04/2023]
Abstract
This Letter describes the development and SAR of a novel series of GlyT1 inhibitors derived from a scaffold hopping approach that provided a robust intellectual property position, in lieu of a traditional, expensive HTS campaign. Members within this new [3.1.0]-based series displayed excellent GlyT1 potency, selectivity, free fraction, CNS penetration and efficacy in a preclinical model of schizophrenia (prepulse inhibition).
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11
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The relationship between glycine transporter 1 occupancy and the effects of the glycine transporter 1 inhibitor RG1678 or ORG25935 on object retrieval performance in scopolamine impaired rhesus monkey. Psychopharmacology (Berl) 2014; 231:511-9. [PMID: 24051602 DOI: 10.1007/s00213-013-3260-0] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/08/2013] [Accepted: 08/19/2013] [Indexed: 12/17/2022]
Abstract
Reduced NMDA receptor functioning is hypothesized to underlie the cognitive and negative symptoms associated with schizophrenia. However, because direct activation of the NMDA receptor is accompanied by neurotoxicity, mechanisms that activate the glycine co-agonist site on the NMDA receptor could carry greater therapeutic potential. In the current study, the effects of two glycine transporter 1 (GlyT1) inhibitors, RG1678 and ORG25935, were characterized in the object-retrieval detour (ORD) task in scopolamine-impaired rhesus monkeys and, using positron emission tomography (PET), the GlyT1 occupancy to efficacy relationship of each compound was established. Scopolamine exerted a significant decrease in accuracy in the ORD task. Lower doses of RG1678 (0.3 and 1.0 mg/kg, p.o.) significantly attenuated the impact of scopolamine, whereas the highest dose tested (1.8 mg/kg) did not. The predicted GlyT1 occupancies of RG1678 at the effective doses were ~10 and 30 %. ORG25935 (0.1, 0.3, and 1 mg/kg, p.o.) also significantly attenuated the impact of scopolamine on the ORD task, whereas 3 mg/kg did not. The predicted GlyT1 occupancies of ORG25935 at the effective doses ranged from 16 to 80 %. These data suggest that GlyT1 inhibitors have the potential to improve performance on prefrontal cortex-dependent tests such as the ORD task, but that efficacy is lost when higher occupancies are achieved. Importantly, recent Ph2B data published by Roche suggests that low but not high doses of RG1678 improved negative symptoms in patients with schizophrenia, highlighting the potential translational nature of the current preclinical findings.
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12
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Glycine transporters as novel therapeutic targets in schizophrenia, alcohol dependence and pain. Nat Rev Drug Discov 2014; 12:866-85. [PMID: 24172334 DOI: 10.1038/nrd3893] [Citation(s) in RCA: 154] [Impact Index Per Article: 15.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Glycine transporters are endogenous regulators of the dual functions of glycine, which acts as a classical inhibitory neurotransmitter at glycinergic synapses and as a modulator of neuronal excitation mediated by NMDA (N-methyl-D-aspartate) receptors at glutamatergic synapses. The two major subtypes of glycine transporters, GlyT1 and GlyT2, have been linked to the pathogenesis and/or treatment of central and peripheral nervous system disorders, including schizophrenia and related affective and cognitive disturbances, alcohol dependence, pain, epilepsy, breathing disorders and startle disease (also known as hyperekplexia). This Review examines the rationale for the therapeutic potential of GlyT1 and GlyT2 inhibition, and surveys the latest advances in the biology of glycine reuptake and transport as well as the drug discovery and clinical development of compounds that block glycine transporters.
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13
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Poels EMP, Kegeles LS, Kantrowitz JT, Slifstein M, Javitt DC, Lieberman JA, Abi-Dargham A, Girgis RR. Imaging glutamate in schizophrenia: review of findings and implications for drug discovery. Mol Psychiatry 2014; 19:20-9. [PMID: 24166406 DOI: 10.1038/mp.2013.136] [Citation(s) in RCA: 144] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/23/2013] [Revised: 08/25/2013] [Accepted: 09/09/2013] [Indexed: 12/11/2022]
Abstract
Currently, all treatments for schizophrenia (SCZ) function primarily by blocking D(2)-type dopamine receptors. Given the limitations of these medications, substantial efforts have been made to identify alternative neurochemical targets for treatment development in SCZ. One such target is brain glutamate. The objective of this article is to review and synthesize the proton magnetic resonance spectroscopy ((1)H MRS) and positron emission tomography (PET)/single-photon emission computed tomography (SPECT) investigations that have examined glutamatergic indices in SCZ, including those of modulatory compounds such as glutathione (GSH) and glycine, as well as data from ketamine challenge studies. The reviewed (1)H MRS and PET/SPECT studies support the theory of hypofunction of the N-methyl-D-aspartate receptor (NMDAR) in SCZ, as well as the convergence between the dopamine and glutamate models of SCZ. We also review several advances in MRS and PET technologies that have opened the door for new opportunities to investigate the glutamate system in SCZ and discuss some ways in which these imaging tools can be used to facilitate a greater understanding of the glutamate system in SCZ and the successful and efficient development of new glutamate-based treatments for SCZ.
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Affiliation(s)
- E M P Poels
- 1] Department of Psychiatry, Columbia University College of Physicians and Surgeons, New York, NY, USA [2] New York State Psychiatric Institute, New York, NY, USA
| | - L S Kegeles
- 1] Department of Psychiatry, Columbia University College of Physicians and Surgeons, New York, NY, USA [2] New York State Psychiatric Institute, New York, NY, USA
| | - J T Kantrowitz
- 1] Department of Psychiatry, Columbia University College of Physicians and Surgeons, New York, NY, USA [2] New York State Psychiatric Institute, New York, NY, USA
| | - M Slifstein
- 1] Department of Psychiatry, Columbia University College of Physicians and Surgeons, New York, NY, USA [2] New York State Psychiatric Institute, New York, NY, USA
| | - D C Javitt
- 1] Department of Psychiatry, Columbia University College of Physicians and Surgeons, New York, NY, USA [2] New York State Psychiatric Institute, New York, NY, USA
| | - J A Lieberman
- 1] Department of Psychiatry, Columbia University College of Physicians and Surgeons, New York, NY, USA [2] New York State Psychiatric Institute, New York, NY, USA
| | - A Abi-Dargham
- 1] Department of Psychiatry, Columbia University College of Physicians and Surgeons, New York, NY, USA [2] New York State Psychiatric Institute, New York, NY, USA [3] Department of Radiology, Columbia University College of Physicians and Surgeons, New York, NY, USA
| | - R R Girgis
- 1] Department of Psychiatry, Columbia University College of Physicians and Surgeons, New York, NY, USA [2] New York State Psychiatric Institute, New York, NY, USA
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GlyT-1 Inhibitors: From Hits to Clinical Candidates. SMALL MOLECULE THERAPEUTICS FOR SCHIZOPHRENIA 2014. [DOI: 10.1007/7355_2014_53] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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Glycine transporter-1 inhibition promotes striatal axon sprouting via NMDA receptors in dopamine neurons. J Neurosci 2013; 33:16778-89. [PMID: 24133278 DOI: 10.1523/jneurosci.3041-12.2013] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
NMDA receptor activity is involved in shaping synaptic connections throughout development and adulthood. We recently reported that brief activation of NMDA receptors on cultured ventral midbrain dopamine neurons enhanced their axon growth rate and induced axonal branching. To test whether this mechanism was relevant to axon regrowth in adult animals, we examined the reinnervation of dorsal striatum following nigral dopamine neuron loss induced by unilateral intrastriatal injections of the toxin 6-hydroxydopamine. We used a pharmacological approach to enhance NMDA receptor-dependent signaling by treatment with an inhibitor of glycine transporter-1 that elevates levels of extracellular glycine, a coagonist required for NMDA receptor activation. All mice displayed sprouting of dopaminergic axons from spared fibers in the ventral striatum to the denervated dorsal striatum at 7 weeks post-lesion, but the reinnervation in mice treated for 4 weeks with glycine uptake inhibitor was approximately twice as dense as in untreated mice. The treated mice also displayed higher levels of striatal dopamine and a complete recovery from lateralization in a test of sensorimotor behavior. We confirmed that the actions of glycine uptake inhibition on reinnervation and behavioral recovery required NMDA receptors in dopamine neurons using targeted deletion of the NR1 NMDA receptor subunit in dopamine neurons. Glycine transport inhibitors promote functionally relevant sprouting of surviving dopamine axons and could provide clinical treatment for disorders such as Parkinson's disease.
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Hargreaves RJ, Rabiner EA. Translational PET imaging research. Neurobiol Dis 2013; 61:32-8. [PMID: 24055214 DOI: 10.1016/j.nbd.2013.08.017] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2013] [Revised: 08/07/2013] [Accepted: 08/14/2013] [Indexed: 10/26/2022] Open
Abstract
The goal of any early central nervous system (CNS) drug development program is always to test the mechanism and not the molecule in order to support additional research investments in late phase clinical trials. Confirmation that drugs reach their targets using translational positron emission tomography (PET) imaging markers of engagement is central to successful clinical proof-of-concept testing and has become an important feature of most neuropsychiatric drug development programs. CNS PET imaging can also play an important role in the clinical investigation of the neuropharmacological basis of psychiatric disease and the optimization of drug therapy.
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Affiliation(s)
- Richard J Hargreaves
- Merck and Co, WP-42-212, 770, Sumneytown Pike, PO Box 4, West Point, PA19486, USA.
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Cioffi CL. Modulation of NMDA receptor function as a treatment for schizophrenia. Bioorg Med Chem Lett 2013; 23:5034-44. [PMID: 23916256 DOI: 10.1016/j.bmcl.2013.07.019] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2013] [Revised: 07/03/2013] [Accepted: 07/13/2013] [Indexed: 11/30/2022]
Abstract
Schizophrenia is a devastating mental illness that afflicts nearly 1% of the world's population. Currently available antipsychotics treat positive symptoms, but are largely ineffective at addressing negative symptoms and cognitive dysfunction. Thus, improved pharmacotherapies that treat all aspects of the disease remain a critical unmet need. There is mounting evidence that links NMDA receptor hypofunction and the expression of schizophrenia, and numerous drug discovery programs have developed agents that directly or indirectly potentiate NMDA receptor-mediated neurotransmission. Several compounds have emerged that show promise for treating all symptom sub-domains in both preclinical models and clinical studies, and we will review recent developments in many of these areas.
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Zhang JC, Toyohara J, Wu J, Ishiwata K, Hashimoto K. In Vivo Evaluation of (11)C-labeled Three Radioligands for Glycine Transporter 1 in the Mouse Brain. CLINICAL PSYCHOPHARMACOLOGY AND NEUROSCIENCE 2013; 10:34-43. [PMID: 23429671 PMCID: PMC3569154 DOI: 10.9758/cpn.2012.10.1.34] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/02/2011] [Revised: 01/04/2012] [Accepted: 01/12/2012] [Indexed: 11/18/2022]
Abstract
Objective Glycine transporter 1 (GlyT-1) is one of the most attractive therapeutic targets for schizophrenia. There is great interest in developing radioligands for in vivo imaging of GlyT-1 in the brain using positron emission tomography. Here, we report the properties of three novel non-sarcosine-based radioligands [11C]CHIBA-3007, [11C]CHIBA-3009, and [11C]CHIBA-3011, for GlyT-1 imaging in the mouse brain in vivo. Methods The three radioligands were synthesized by N-[11C] methylation of the corresponding desmethyl precursor. A pharmacological characterization of these radioligands for in vivo imaging of GlyT-1 in the brain was conducted using male ddY mice. Results [11C]CHIBA-3009 and [11C]CHIBA-3011 were scarcely incorporated into the brain, whereas [11C]CHIBA-3007 showed slight but considerable brain uptake. Regional brain uptake of [11C]CHIBA-3007 (medulla oblongata>cerebellum>cortex) was similar to the distribution of the GlyT-1 protein. However, pretreatment with CHIBA-3007 (1 mg/kg) or the GlyT-1 selective inhibitor ALX5407 (N-[(3R)-3-([1,1'-Biphenyl]-4-yloxy)-3-(4-fluorophenyl)propyl]-N-methylglycine) (30 mg/kg) did not significantly decrease brain uptake of [11C]CHIBA-3007, suggesting low specific binding to GlyT-1. Pretreatment with cyclosporin A significantly increased brain uptake of [11C]CHIBA-3009 and [11C]CHIBA-3011, suggesting a role for P-glycoprotein in the brain uptake of these ligands. All three radioligands were rapidly degraded intact forms were 3-18% in plasma and 15-74% in the brain at 15 min after injection. Conclusion The results suggest that these three radioligands are not suitable for in vivo imaging of GlyT-1 in the brain because of low brain uptake and rapid metabolism. Further structural refinement is necessary to enhance brain uptake.
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Affiliation(s)
- Ji-Chun Zhang
- Division of Clinical Neuroscience, Chiba University Center for Forensic Mental Health, Chiba, Japan
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Glycine transporter type 1 occupancy by bitopertin: a positron emission tomography study in healthy volunteers. Neuropsychopharmacology 2013; 38:504-12. [PMID: 23132267 PMCID: PMC3547202 DOI: 10.1038/npp.2012.212] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Deficient N-methyl-D-aspartate (NMDA) receptor transmission is thought to underlie schizophrenia. An approach for normalizing glutamate neurotransmission by enhancing NMDA receptor transmission is to increase glycine availability by inhibiting the glycine transporter type 1 (GlyT1). This study investigated the relationship between the plasma concentration of the glycine reuptake inhibitor bitopertin (RG1678) and brain GlyT1 occupancy. Healthy male volunteers received up to 175 mg bitopertin once daily, for 10-12 days. Three positron emission tomography scans, preceded by a single intravenous infusion of ∼30 mCi [(11)C]RO5013853, were performed: at baseline, on the last day of bitopertin treatment, and 2 days after drug discontinuation. Eighteen subjects were enrolled. At baseline, regional volume of distribution (V(T)) values were highest in the pons, thalamus, and cerebellum (1.7-2.7 ml/cm(3)) and lowest in cortical areas (∼0.8 ml/cm(3)). V(T) values were reduced to a homogeneous level following administration of 175 mg bitopertin. Occupancy values derived by a two-tissue five-parameter (2T5P) model, a simplified reference tissue model (SRTM), and a pseudoreference tissue model (PRTM) were overall comparable. At steady state, the relationship between bitopertin plasma concentration and GlyT1 occupancy derived by the 2T5P model, SRTM, and PRTM exhibited an EC(50) of ∼190, ∼200, and ∼130 ng/ml, respectively. E(max) was ∼92% independently of the model used. Bitopertin plasma concentration was a reliable predictor of occupancy because the concentration-occupancy relationship was superimposable at steady state and 2 days after drug discontinuation. These data allow understanding of the concentration-occupancy-efficacy relationship of bitopertin and support dose selection of future molecules.
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Abstract
Schizophrenia is a severe neuropsychiatric disorder without adequate current treatment. Recent theories of schizophrenia focus on disturbances of glutamatergic neurotransmission particularly at N-methyl-D-aspartate (NMDA)-type glutamate receptors. NMDA receptors are regulated in vivo by the amino acids glycine and D-serine. Glycine levels, in turn, are regulated by glycine type I (GlyT1) transporters, which serve to maintain low subsaturating glycine levels in the vicinity of the NMDA receptor. A proposed approach to treatment of schizophrenia, therefore, is inhibition of GlyT1-mediated transport. Over the past decade, several well tolerated, high affinity GlyT1 inhibitors have been developed and shown to potentiate NMDA receptor-mediated neurotransmission in animal models relevant to schizophrenia. In addition, clinical trials have been conducted with sarcosine (N-methylglycine), a naturally occurring GlyT1 inhibitor, and with the high affinity compound RG1678. Although definitive trials remain ongoing, encouraging results to date have been reported.
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Affiliation(s)
- Daniel C Javitt
- Nathan S Kline Institute for Psychiatric Research, Columbia University, Orangeburg, NY 10962, USA.
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Dervola KS, Roberg BA, Wøien G, Bogen IL, Sandvik TH, Sagvolden T, Drevon CA, Johansen EB, Walaas SI. Marine Ο-3 polyunsaturated fatty acids induce sex-specific changes in reinforcer-controlled behaviour and neurotransmitter metabolism in a spontaneously hypertensive rat model of ADHD. Behav Brain Funct 2012; 8:56. [PMID: 23228189 PMCID: PMC3573936 DOI: 10.1186/1744-9081-8-56] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2012] [Accepted: 11/28/2012] [Indexed: 01/19/2023] Open
Abstract
Background Previous reports suggest that omega-3 (n-3) polyunsaturated fatty acids (PUFA) supplements may reduce ADHD-like behaviour. Our aim was to investigate potential effects of n-3 PUFA supplementation in an animal model of ADHD. Methods We used spontaneously hypertensive rats (SHR). SHR dams were given n-3 PUFA (EPA and DHA)-enriched feed (n-6/n-3 of 1:2.7) during pregnancy, with their offspring continuing on this diet until sacrificed. The SHR controls and Wistar Kyoto (WKY) control rats were given control-feed (n-6/n-3 of 7:1). During postnatal days (PND) 25–50, offspring were tested for reinforcement-dependent attention, impulsivity and hyperactivity as well as spontaneous locomotion. The animals were then sacrificed at PND 55–60 and their neostriata were analysed for monoamine and amino acid neurotransmitters with high performance liquid chromatography. Results n-3 PUFA supplementation significantly enhanced reinforcement-controlled attention and reduced lever-directed hyperactivity and impulsiveness in SHR males whereas the opposite or no effects were observed in females. Analysis of neostriata from the same animals showed significantly enhanced dopamine and serotonin turnover ratios in the male SHRs, whereas female SHRs showed no change, except for an intermediate increase in serotonin catabolism. In contrast, both male and female SHRs showed n-3 PUFA-induced reduction in non-reinforced spontaneous locomotion, and sex-independent changes in glycine levels and glutamate turnover. Conclusions Feeding n-3 PUFAs to the ADHD model rats induced sex-specific changes in reinforcement-motivated behaviour and a sex-independent change in non-reinforcement-associated behaviour, which correlated with changes in presynaptic striatal monoamine and amino acid signalling, respectively. Thus, dietary n-3 PUFAs may partly ameliorate ADHD-like behaviour by reinforcement-induced mechanisms in males and partly via reinforcement-insensitive mechanisms in both sexes.
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Affiliation(s)
- Kine S Dervola
- Department of Biochemistry, Institute of Basic Medical Science, Faculty of Medicine, University of Oslo, Oslo, Norway.
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Morrow JA, Gilfillan R, Neale SA. Glutamatergic Approaches for the Treatment of Schizophrenia. DRUG DISCOVERY FOR PSYCHIATRIC DISORDERS 2012. [DOI: 10.1039/9781849734943-00056] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Glutamate is the major excitatory neurotransmitter in the mammalian central nervous system and plays a key role in most aspects of normal brain function including cognition, learning and memory. Dysfunction of glutamatergic neurotransmission has been implicated in a number of neurological and psychiatric disorders with a growing body of evidence suggesting that hypofunction of glutamatergic neurotransmission via the N-methyl-d-aspartate (NMDA) receptor plays an important role in the pathophysiology of schizophrenia. It thus follows that potentiation of NMDA receptor function via pharmacological manipulation may provide therapeutic utility for the treatment of schizophrenia and a number of different approaches are currently being pursued by the pharmaceutical industry with this aim in mind. These include strategies that target the glycine/d-serine site of the NMDA receptor (glycine transporter GlyT1, d-serine transporter ASC-1 and d-amino acid oxidase (DAAO) inhibitors) together with those aimed at enhancing glutamatergic neurotransmission via modulation of AMPA receptor and metabotropic glutamate receptor function. Such efforts are now beginning to bear fruit with compounds such as the GlyT1 inhibitor RG1678 and mGlu2 agonist LY2140023 proving to have clinical meaningful effects in phase II clinical trials. While more studies are required to confirm long-term efficacy, functional outcome and safety in schizophrenic agents, these agents hold real promise for addressing unmet medical needs, in particular refractory negative and cognitive symptoms, not currently addressed by existing antipsychotic agents.
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Affiliation(s)
- John A. Morrow
- Neuroscience and Ophthalmology, Merck Research Laboratories 2015 Galloping Hill Road, Kenilworth, New Jersey 07033 USA
| | - Robert Gilfillan
- Discovery Chemistry, Merck Research Laboratories 770 Sumneytown Pike, West Point, Pennsylvania 19486 USA
| | - Stuart A. Neale
- Neurexpert Ltd Ground Floor, 2 Woodberry Grove, North Finchley, London, N12 0DR UK
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Ozaki S. [Role of neuroimaging biomarker in drug discovery for schizophrenia]. Nihon Yakurigaku Zasshi 2012; 140:107-10. [PMID: 22975823 DOI: 10.1254/fpj.140.107] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Fuchigami T, Takano A, Gulyás B, Jia Z, Finnema SJ, Andersson JD, Nakao R, Magata Y, Haratake M, Nakayama M, Halldin C. Synthesis and evaluation of 2-chloro N-[(S)-{(S)-1-[11 C]methylpiperidin-2-yl} (phenyl)methyl]3-trifluoromethyl-benzamide ([11 C]N-methyl-SSR504734) as a PET radioligand for glycine transporter 1. EJNMMI Res 2012; 2:37. [PMID: 22776065 PMCID: PMC3531252 DOI: 10.1186/2191-219x-2-37] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2012] [Accepted: 06/01/2012] [Indexed: 11/10/2022] Open
Abstract
UNLABELLED BACKGROUND Dysfunction of the glycine transporter 1 (GlyT1) has been suggested to be involved in psychiatric disorders such as schizophrenia. GlyT1 inhibitors have therefore been considered to have antipsychotic therapeutic potential. Positron emission tomography (PET) imaging probes for GlyT1 are, consequently, expected to be useful for investigating the mechanism of such disease conditions and for measuring occupancy of GlyT1 inhibitors in vivo. The aim of this study was to assess the potential of 2-chloro N-[(S)-{(S)-1-[11 C]methylpiperidin-2-yl} (phenyl)methyl] 3-trifluoromethyl-benzamide ([11 C]N-methyl-SSR504734) as a PET imaging agent for GlyT1. METHODS [11 C]N-methyl-SSR504734 was synthesized by N-[11 C]methylation of SSR504734 via [11 C]CH3OTf. In vitro brain distribution of [11 C]N-methyl-SSR504734 was tested in whole-hemisphere autoradiography (ARG) on human brain slices. Initial PET studies were performed using a cynomolgus monkey at baseline and after pretreatment with 0.1 to 1.5 mg/kg of SSR504734. Then, PET studies using rhesus monkeys were performed with arterial blood sampling at baseline and after pretreatment with 1.5 to 4.5 mg/kg SSR504734. Distribution volumes (VT) were calculated with a two-tissue compartment model, and GlyT1 occupancy by SSR504734 was estimated using a Lassen plot approach. RESULTS [11 C]N-methyl-SSR504734 was successfully synthesized in moderate radiochemical yield and high specific radioactivity. In the ARG experiments, [11 C]N-methyl-SSR504734 showed specific binding in the white matter and pons. In the initial PET experiments in a cynomolgus monkey, [11 C]N-methyl-SSR504734 showed high brain uptake and consistent distribution with previously reported GlyT1 expression in vivo (thalamus, brainstem > cerebellum > cortical regions). However, the brain uptake increased after pretreatment with SSR504734. Further PET studies in rhesus monkeys showed a similar increase of brain uptake after pretreatment with SSR504734. However, the VT of [11 C]N-methyl-SSR504734 was found to decrease after pretreatment of SSR504734 in a dose-dependent manner. GlyT1 occupancy was calculated to be 45% and 73% at 1.5 and 4.5 mg/kg of SSR504734, respectively. CONCLUSIONS [11 C]N-methyl-SSR504734 is demonstrated to be a promising PET radioligand for GlyT1 in nonhuman primates. The present results warrant further PET studies in human subjects.
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Affiliation(s)
- Takeshi Fuchigami
- Karolinska Institutet, Department of Clinical Neuroscience, Center for Psychiatric Research, Karolinska University Hospital, R5:02, Stockholm 171 76, Sweden.
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Psychopharmacological treatment of schizophrenia: What do we have, and what could we get? Neuropharmacology 2012; 62:1371-80. [DOI: 10.1016/j.neuropharm.2011.03.013] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2011] [Revised: 03/07/2011] [Accepted: 03/10/2011] [Indexed: 12/20/2022]
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Borroni E, Zhou Y, Ostrowitzki S, Alberati D, Kumar A, Hainzl D, Hartung T, Hilton J, Dannals RF, Wong DF. Pre-clinical characterization of [11C]R05013853 as a novel radiotracer for imaging of the glycine transporter type 1 by positron emission tomography. Neuroimage 2011; 75:291-300. [PMID: 22178811 DOI: 10.1016/j.neuroimage.2011.11.090] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2011] [Revised: 11/24/2011] [Accepted: 11/30/2011] [Indexed: 11/19/2022] Open
Abstract
A specific positron emission tomography (PET) radiotracer for the glycine transporter type 1 (GlyT1) would constitute an imaging biomarker to investigate the distribution of GlyT1 in normal individuals and those with neuropsychiatric disorders. In addition it could demonstrate the ability of a novel drug to reach its target in the brain and enable receptor occupancy studies, thus facilitating drug development. In this article we describe the evaluation in non-human primates of two candidate PET radiotracers ([(11)C]RO5013852 and [(11)C]RO5013853) previously characterized in the rat. Both radiotracers showed acceptable uptake in the baboon brain and heterogeneous distribution consistent with that reported for GlyT1. In vivo blockade studies with two specific glycine reuptake inhibitors (GRIs), RO5013853 and bitopertin (RG1678, reduced uptake of both tracers to homogenous levels across brain regions and demonstrated specificity of the signal. [(11)C]RO5013853 showed a larger specific signal and slightly higher brain uptake and was therefore selected for further characterization. Quantitative compartmental analysis of PET data showed that the 2-tissue compartment model with 5 parameters was the most appropriate to describe the kinetics of [(11)C]RO5013853. Two additional methods were used: a) the Logan graphical analysis using plasma input and, b) a linear parametric imaging approach with the 2-tissue compartmental model. These produced VT estimates of comparable magnitude, namely, pons, thalamus and cerebellum>caudate, putamen and cortical regions. High resolution autoradiography with tritiated RO5013853 was used to confirm the binding pattern observed by PET. In vivo metabolism studies in the baboon demonstrated the formation of a single, radiolabeled metabolite more polar than the parent compound. Finally, [(11)C]RO5013853 was used to quantify the degree of cerebral GlyT1 occupancy observed in the baboon following oral administration of bitopertin, a selective GRI presently in Phase III clinical trial. Plasma concentrations of approximately 150-300 ng/mL were estimated to produce 50% GlyT1 occupancy in the thalamus, the cerebellum and the pons. [(11)C]RO5013853 is a promising radiotracer for in vivo imaging of the GlyT1. It can be easily radiolabeled, exhibits moderate metabolism, displays a good specific signal, and is suitable for receptor occupancy studies of therapeutic compounds that target the GlyT1. The successful characterization of [(11)C]RO5013853 in healthy volunteers is presented in this NeuroImage issue (Wong et al., 2013).
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Affiliation(s)
- Edilio Borroni
- Neuroscience Department, Pharmaceutical Division, F. Hoffmann-La Roche Ltd, CH-4070 Basel, Switzerland.
| | - Yun Zhou
- The Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, MD 21287-0807, USA
| | - Susanne Ostrowitzki
- Neuroscience Department, Pharmaceutical Division, F. Hoffmann-La Roche Ltd, CH-4070 Basel, Switzerland
| | - Daniela Alberati
- Neuroscience Department, Pharmaceutical Division, F. Hoffmann-La Roche Ltd, CH-4070 Basel, Switzerland
| | - Anil Kumar
- The Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, MD 21287-0807, USA
| | - Dominik Hainzl
- Nonclinical Safety Department, Pharmaceutical Division, F. Hoffmann-La Roche Ltd, CH-4070 Basel, Switzerland
| | - Thomas Hartung
- Process Research & Synthesis Department, Pharmaceutical Division, F. Hoffmann-La Roche Ltd, CH-4070 Basel, Switzerland
| | - John Hilton
- The Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, MD 21287-0807, USA
| | - Robert F Dannals
- The Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, MD 21287-0807, USA
| | - Dean F Wong
- The Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, MD 21287-0807, USA; Department of Psychiatry, The Johns Hopkins University School of Medicine, 601 N. Caroline St., JHOC, Baltimore, MD 21287-0807, USA; Department of Neuroscience, The Johns Hopkins University School of Medicine, 601 N. Caroline St., JHOC, Baltimore, MD 21287-0807, USA; Department of Environmental Health Sciences, The Johns Hopkins University School of Medicine, 601 N. Caroline St., JHOC, Baltimore, MD 21287-0807, USA; Honorary Professor of Neuroscience and Pharmacology, University of Copenhagen, Denmark
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Wong DF, Ostrowitzki S, Zhou Y, Raymont V, Hofmann C, Borroni E, Kumar A, Parkar N, Brašić JR, Hilton J, Dannals RF, Martin-Facklam M. Characterization of [11C]RO5013853, a novel PET tracer for the glycine transporter type 1 (GlyT1) in humans. Neuroimage 2011; 75:282-290. [PMID: 22155032 DOI: 10.1016/j.neuroimage.2011.11.052] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2011] [Revised: 11/08/2011] [Accepted: 11/14/2011] [Indexed: 11/26/2022] Open
Abstract
We characterize a novel radioligand for the glycine transporter type 1 (GlyT1), [(11)C]RO5013853, in humans. Ten healthy male volunteers, 23-60 years of age, were enrolled in this PET study; seven subjects participated in the evaluation of test-retest reliability and three subjects in whole body dosimetry. Subjects were administered intravenous bolus injections of approximately 1100 MBq (30 mCi) [(11)C]RO5013853 with a high specific activity of about 481 GBq (13 Ci)/μmol. Standard compartmental model analysis with arterial plasma input function, and an alternative noninvasive analysis method which was evaluated and validated by occupancy studies in both baboons and humans, were performed. Mean parameter estimates of the volumes of distribution (VT) obtained by a 2-tissue 5-parameter model were higher in the cerebellum, pons, and thalamus (1.99 to 2.59 mL/mL), and lower in the putamen, caudate, and cortical areas (0.86 to 1.13 mL/mL), with estimates showing less than 10% difference between test and retest scans. Tracer retention was effectively blocked by the specific glycine reuptake inhibitor (GRI), bitopertin (RG1678). [(11)C]RO5013853 was safe and well tolerated. Human dosimetry studies showed that the effective dose was approximately 0.0033 mSv/MBq, with the liver receiving the highest absorbed dose. In conclusion, quantitative dynamic PET of the human brain after intravenous injection of [(11)C]RO5013853 attains reliable measurements of GlyT1 binding in accordance with the expected transporter distribution in the human brain. [(11)C]RO5013853 is a radioligand suitable for further clinical PET studies. Full characterization of a novel radiotracer for GlyT1 in humans is provided. The tracer has subsequently been used to assess receptor occupancy in healthy volunteers and to estimate occupancy at doses associated with best efficacy in a clinical trial with schizophrenic patients with predominantly negative symptoms.
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Affiliation(s)
- Dean F Wong
- The Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, 601 North Caroline Street, Room 3245, Johns Hopkins Outpatient Center, Baltimore, MD 21287 -0807, USA; Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21287-0807, USA; Department of Environmental Health Sciences, Johns Hopkins University School of Medicine, Baltimore, MD 21287-0807, USA; Department of Psychiatry, Johns Hopkins University School of Medicine, Baltimore, MD 21287 -0807, USA; Honorary Professor of Neuroscience and Pharmacology, University of Copenhagen, Denmark.
| | - Susanne Ostrowitzki
- F. Hoffmann-La Roche Ltd., Pharmaceutical Division, Grenzacherstrasse 124, CH-4070 Basel, Switzerland
| | - Yun Zhou
- Department of Psychiatry, Johns Hopkins University School of Medicine, Baltimore, MD 21287 -0807, USA
| | - Vanessa Raymont
- Department of Psychiatry, Johns Hopkins University School of Medicine, Baltimore, MD 21287 -0807, USA
| | - Carsten Hofmann
- F. Hoffmann-La Roche Ltd., Pharmaceutical Division, Grenzacherstrasse 124, CH-4070 Basel, Switzerland
| | - Edilio Borroni
- F. Hoffmann-La Roche Ltd., Pharmaceutical Division, Grenzacherstrasse 124, CH-4070 Basel, Switzerland
| | - Anil Kumar
- Department of Psychiatry, Johns Hopkins University School of Medicine, Baltimore, MD 21287 -0807, USA
| | - Nikhat Parkar
- F. Hoffmann-La Roche Ltd., Pharmaceutical Division, Grenzacherstrasse 124, CH-4070 Basel, Switzerland
| | - James R Brašić
- Department of Psychiatry, Johns Hopkins University School of Medicine, Baltimore, MD 21287 -0807, USA
| | - John Hilton
- Department of Psychiatry, Johns Hopkins University School of Medicine, Baltimore, MD 21287 -0807, USA
| | - Robert F Dannals
- Department of Psychiatry, Johns Hopkins University School of Medicine, Baltimore, MD 21287 -0807, USA
| | - Meret Martin-Facklam
- F. Hoffmann-La Roche Ltd., Pharmaceutical Division, Grenzacherstrasse 124, CH-4070 Basel, Switzerland
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Fuchigami T, Haratake M, Magata Y, Haradahira T, Nakayama M. Synthesis and characterization of [125I]2-iodo N-[(S)-{(S)-1-methylpiperidin-2-yl}(phenyl)methyl]3-trifluoromethyl-benzamide as novel imaging probe for glycine transporter 1. Bioorg Med Chem 2011; 19:6245-53. [DOI: 10.1016/j.bmc.2011.09.010] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2011] [Revised: 09/06/2011] [Accepted: 09/07/2011] [Indexed: 01/12/2023]
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Hostetler ED, Sanabria-Bohórquez S, Fan H, Zeng Z, Gammage L, Miller P, O'Malley S, Connolly B, Mulhearn J, Harrison ST, Wolkenberg SE, Barrow JC, Williams DL, Hargreaves RJ, Sur C, Cook JJ. [18F]Fluoroazabenzoxazoles as potential amyloid plaque PET tracers: synthesis and in vivo evaluation in rhesus monkey. Nucl Med Biol 2011; 38:1193-203. [DOI: 10.1016/j.nucmedbio.2011.04.004] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2011] [Revised: 03/22/2011] [Accepted: 04/13/2011] [Indexed: 12/28/2022]
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Sanabria-Bohórquez SM, Joshi AD, Holahan M, Daneker L, Riffel K, Williams M, Li W, Cook JJ, Hamill TG. Quantification of the glycine transporter 1 in rhesus monkey brain using [18F]MK-6577 and a model-based input function. Neuroimage 2011; 59:2589-99. [PMID: 21930214 DOI: 10.1016/j.neuroimage.2011.08.080] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2011] [Revised: 08/23/2011] [Accepted: 08/25/2011] [Indexed: 10/17/2022] Open
Abstract
BACKGROUND Glycine transporter 1 (GlyT1) inhibitors have emerged as potential treatments for schizophrenia due to their potentiation of NMDA receptor activity by modulating the local concentrations of the NMDA co-agonist glycine. [18F]MK-6577 is a potent and selective GlyT1 inhibitor PET tracer. Although differences in ligand kinetics can be expected between non-human primates and humans, the tracer pre-clinical evaluation can provide valuable information supporting protocol design and quantification in the clinical space. The main objective of this work was to evaluate the in vivo kinetics of [18F]MK-6577 in rhesus monkey brain. Additionally, a method for estimating the tracer input function from the tracer brain tissue kinetics and venous sampling was validated. This technique was applied for determination of the dose-occupancy relationship of a GlyT1 inhibitor in monkey brain. METHODS Compartmental and Logan graphical analysis were utilized for quantification of the [18F]MK-6577 binding using the measured tracer arterial input function. The stability of the tracer volume of distribution relative to scan length was assessed. The proposed model-based input function method takes advantage of the agreement between the tracer concentration in arterial and venous plasma from ~5 min. The approach estimates the initial peak of the input curve by adding a gamma like function term to the measured venous curve. The parameters of the model function were estimated by simultaneously fitting several brain time activity curves to a compartmental model. RESULTS Good agreement was found between the model-based and the measured arterial plasma curve and the corresponding distribution volumes. The Logan analysis was the preferred method of analysis providing reliable and stable volume of distribution and occupancy results using a 90 and possibly 60 min scan length. CONCLUSION The model-based input function method and Logan analysis are well suited for quantification of [18F]MK-6577 binding and GlyT1 occupancy in monkey brain.
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Gunn RN, Murthy V, Catafau AM, Searle G, Bullich S, Slifstein M, Ouellet D, Zamuner S, Herance R, Salinas C, Pardo-Lozano R, Rabiner EA, Farre M, Laruelle M. Translational characterization of [11C]GSK931145, a PET ligand for the glycine transporter type 1. Synapse 2011; 65:1319-32. [DOI: 10.1002/syn.20966] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2011] [Revised: 06/07/2011] [Accepted: 06/10/2011] [Indexed: 11/08/2022]
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Blackaby WP, Lewis RT, Thomson JL, Jennings ASR, Goodacre SC, Street LJ, MacLeod AM, Pike A, Wood S, Thomas S, Brown TA, Smith A, Pillai G, Almond S, Guscott MR, Burns HD, Eng W, Ryan C, Cook J, Hamill TG. Identification of an Orally Bioavailable, Potent, and Selective Inhibitor of GlyT1. ACS Med Chem Lett 2010; 1:350-4. [PMID: 24900218 DOI: 10.1021/ml1001085] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2010] [Accepted: 06/21/2010] [Indexed: 11/30/2022] Open
Abstract
Amalgamation of the structure-activity relationship of two series of GlyT1 inhibitors developed at Merck led to the discovery of a clinical candidate, compound 16 (DCCCyB), which demonstrated excellent in vivo occupancy of GlyT1 transporters in rhesus monkey as determined by displacement of a PET tracer ligand.
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Affiliation(s)
- Wesley P. Blackaby
- Merck Sharp and Dohme, Neuroscience Research Centre, Terlings Park, Eastwick Road, Harlow, Essex CM20 2QR, United Kingdom
| | - Richard T. Lewis
- Merck Sharp and Dohme, Neuroscience Research Centre, Terlings Park, Eastwick Road, Harlow, Essex CM20 2QR, United Kingdom
| | - Joanne L. Thomson
- Merck Sharp and Dohme, Neuroscience Research Centre, Terlings Park, Eastwick Road, Harlow, Essex CM20 2QR, United Kingdom
| | - Andrew S. R. Jennings
- Merck Sharp and Dohme, Neuroscience Research Centre, Terlings Park, Eastwick Road, Harlow, Essex CM20 2QR, United Kingdom
| | - Simon C. Goodacre
- Merck Sharp and Dohme, Neuroscience Research Centre, Terlings Park, Eastwick Road, Harlow, Essex CM20 2QR, United Kingdom
| | - Leslie J. Street
- Merck Sharp and Dohme, Neuroscience Research Centre, Terlings Park, Eastwick Road, Harlow, Essex CM20 2QR, United Kingdom
| | - Angus M. MacLeod
- Merck Sharp and Dohme, Neuroscience Research Centre, Terlings Park, Eastwick Road, Harlow, Essex CM20 2QR, United Kingdom
| | - Andrew Pike
- Merck Sharp and Dohme, Neuroscience Research Centre, Terlings Park, Eastwick Road, Harlow, Essex CM20 2QR, United Kingdom
| | - Suzanne Wood
- Merck Sharp and Dohme, Neuroscience Research Centre, Terlings Park, Eastwick Road, Harlow, Essex CM20 2QR, United Kingdom
| | - Steve Thomas
- Merck Sharp and Dohme, Neuroscience Research Centre, Terlings Park, Eastwick Road, Harlow, Essex CM20 2QR, United Kingdom
| | - Terry A. Brown
- Merck Sharp and Dohme, Neuroscience Research Centre, Terlings Park, Eastwick Road, Harlow, Essex CM20 2QR, United Kingdom
| | - Alison Smith
- Merck Sharp and Dohme, Neuroscience Research Centre, Terlings Park, Eastwick Road, Harlow, Essex CM20 2QR, United Kingdom
| | - Gopalan Pillai
- Merck Sharp and Dohme, Neuroscience Research Centre, Terlings Park, Eastwick Road, Harlow, Essex CM20 2QR, United Kingdom
| | - Sarah Almond
- Merck Sharp and Dohme, Neuroscience Research Centre, Terlings Park, Eastwick Road, Harlow, Essex CM20 2QR, United Kingdom
| | - Martin R. Guscott
- Merck Sharp and Dohme, Neuroscience Research Centre, Terlings Park, Eastwick Road, Harlow, Essex CM20 2QR, United Kingdom
| | - H. Donald Burns
- Research Imaging, Merck Research Laboratories, West Point, Pennsylvania 19486
| | - Waisi Eng
- Research Imaging, Merck Research Laboratories, West Point, Pennsylvania 19486
| | - Christine Ryan
- Research Imaging, Merck Research Laboratories, West Point, Pennsylvania 19486
| | - Jacquelynn Cook
- Research Imaging, Merck Research Laboratories, West Point, Pennsylvania 19486
| | - Terence G. Hamill
- Research Imaging, Merck Research Laboratories, West Point, Pennsylvania 19486
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