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Tian Z, Zuo Y, Xi P, Meng X, Shao W, Yang Y, Ren Q, Yu J, Xie Z. A novel relative-equilibrium graphical plot for rapid reversible tracer studies in dynamic PET imaging. Phys Med Biol 2024; 69:165005. [PMID: 38996417 DOI: 10.1088/1361-6560/ad62d2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2024] [Accepted: 07/12/2024] [Indexed: 07/14/2024]
Abstract
Objective.This study aims to address the issue of long scan durations required by traditional graphical analysis methods, such as the Logan plot and its variant, the reversible equilibrium (RE) Logan plot, for dynamic PET imaging of tracer kinetics.Approach.We propose a relative RE Logan model that builds on the principles of the Logan plot and its variant to significantly reduce scan time without compromising the accuracy of tracer kinetics analysis. The model is supported by theoretical evidence and experimental validations, including two computer simulations and one clinical data analysis.Main results.The proposed model demonstrates a significant linear relationship between the variablexand the slopeDVTof the RE Logan plot, and the variablex' and the slopeDVT'of the relative RE Logan plot. The Pearson correlation coefficients (r) of the linear fitting of thex' to thexequal 0.9849 in the simulated data and 0.9912 in the clinical data. Similarly, thervalues for the linear fitting ofDVT'toDVTequal 0.9989 and 0.9988 in the simulated data, and 0.9954 in the clinical data.Significance.These results demonstrate the model's capability to maintain strong linear relationships and produce parametric images comparable to the traditional RE Logan plot, but with the considerable advantage of shorter scan durations. This innovation holds significant potential for enhancing the efficiency and feasibility of PET imaging in clinical settings.
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Affiliation(s)
- Zifeng Tian
- Department of Biomedical Engineering, College of Future Technology, Peking University, Beijing 100871, People's Republic of China
| | - Yang Zuo
- Department of Engineering and Applied Physics, University of Science and Technology of China, Hefei, Anhui 230026, People's Republic of China
| | - Peng Xi
- Department of Biomedical Engineering, College of Future Technology, Peking University, Beijing 100871, People's Republic of China
| | - Xiangxi Meng
- Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education/Beijing), Key Laboratory for Research and Evaluation of Radiopharmaceuticals (NMPA), Department of Nuclear Medicine, Peking University Cancer Hospital & Institute, Beijing 100142, People's Republic of China
| | - Wenrui Shao
- Institute of Medical Technology, Peking University Health Science Center, Peking University, Beijing 100191, People's Republic of China
| | - Yidong Yang
- Department of Engineering and Applied Physics, University of Science and Technology of China, Hefei, Anhui 230026, People's Republic of China
- Department of Radiation Oncology, The First Affiliated Hospital of USTC, University of Science and Technology of China, Hefei, Anhui 230026, People's Republic of China
- Ion Medical Research Institute, University of Science and Technology of China, Hefei, Anhui 230026, People's Republic of China
| | - Qiushi Ren
- Department of Biomedical Engineering, College of Future Technology, Peking University, Beijing 100871, People's Republic of China
- National Biomedical Imaging Center, Peking University, Beijing 100871, People's Republic of China
- Institute of Biomedical Engineering, Shenzhen Bay Laboratory, Shengzhen 518106, People's Republic of China
| | - Jiangyuan Yu
- Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education/Beijing), Key Laboratory for Research and Evaluation of Radiopharmaceuticals (NMPA), Department of Nuclear Medicine, Peking University Cancer Hospital & Institute, Beijing 100142, People's Republic of China
| | - Zhaoheng Xie
- Institute of Medical Technology, Peking University Health Science Center, Peking University, Beijing 100191, People's Republic of China
- National Biomedical Imaging Center, Peking University, Beijing 100871, People's Republic of China
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2
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Kiilerich KF, Lorenz J, Scharff MB, Speth N, Brandt TG, Czurylo J, Xiong M, Jessen NS, Casado-Sainz A, Shalgunov V, Kjaerby C, Satała G, Bojarski AJ, Jensen AA, Herth MM, Cumming P, Overgaard A, Palner M. Repeated low doses of psilocybin increase resilience to stress, lower compulsive actions, and strengthen cortical connections to the paraventricular thalamic nucleus in rats. Mol Psychiatry 2023; 28:3829-3841. [PMID: 37783788 DOI: 10.1038/s41380-023-02280-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/30/2022] [Revised: 09/12/2023] [Accepted: 09/20/2023] [Indexed: 10/04/2023]
Abstract
Psilocybin (a classic serotonergic psychedelic drug) has received appraisal for use in psychedelic-assisted therapy of several psychiatric disorders. A less explored topic concerns the use of repeated low doses of psychedelics, at a dose that is well below the psychedelic dose used in psychedelic-assisted therapy and often referred to as microdosing. Psilocybin microdose users frequently report increases in mental health, yet such reports are often highly biased and vulnerable to placebo effects. Here we establish and validate a psilocybin microdose-like regimen in rats with repeated low doses of psilocybin administration at a dose derived from occupancy at rat brain 5-HT2A receptors in vivo. The rats tolerated the repeated low doses of psilocybin well and did not manifest signs of anhedonia, anxiety, or altered locomotor activity. There were no deficits in pre-pulse inhibition of the startle reflex, nor did the treatment downregulate or desensitize the 5-HT2A receptors. However, the repeated low doses of psilocybin imparted resilience against the stress of multiple subcutaneous injections, and reduced the frequency of self-grooming, a proxy for human compulsive actions, while also increasing 5-HT7 receptor expression and synaptic density in the paraventricular nucleus of the thalamus. These results establish a well-validated regimen for further experiments probing the effects of repeated low doses of psilocybin. Results further substantiate anecdotal reports of the benefits of psilocybin microdosing as a therapeutic intervention, while pointing to a possible physiological mechanism.
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Affiliation(s)
- Kat F Kiilerich
- Neurobiology Research Unit, Copenhagen University Hospital, Copenhagen, Denmark
| | - Joe Lorenz
- Neurobiology Research Unit, Copenhagen University Hospital, Copenhagen, Denmark
| | - Malthe B Scharff
- Neurobiology Research Unit, Copenhagen University Hospital, Copenhagen, Denmark
| | - Nikolaj Speth
- Neurobiology Research Unit, Copenhagen University Hospital, Copenhagen, Denmark
| | - Tobias G Brandt
- Clinical Physiology and Nuclear Medicine, Department of Clinical Research, University of Southern Denmark, Odense, Denmark
| | - Julia Czurylo
- Clinical Physiology and Nuclear Medicine, Department of Clinical Research, University of Southern Denmark, Odense, Denmark
| | - Mengfei Xiong
- Neurobiology Research Unit, Copenhagen University Hospital, Copenhagen, Denmark
- Department of Drug Design and Pharmacology, University of Copenhagen, Copenhagen, Denmark
| | - Naja S Jessen
- Neurobiology Research Unit, Copenhagen University Hospital, Copenhagen, Denmark
- Clinical Physiology and Nuclear Medicine, Department of Clinical Research, University of Southern Denmark, Odense, Denmark
| | - Agata Casado-Sainz
- Neurobiology Research Unit, Copenhagen University Hospital, Copenhagen, Denmark
| | - Vladimir Shalgunov
- Department of Drug Design and Pharmacology, University of Copenhagen, Copenhagen, Denmark
- Department of Clinical Physiology, Nuclear Medicine and PET, Copenhagen University Hospital, Copenhagen, Denmark
| | - Celia Kjaerby
- Center for Translational Neuromedicine, University of Copenhagen, Copenhagen, Denmark
| | - Grzegorz Satała
- Department of Medicinal Chemistry, Maj Institute of Pharmacology, Polish Academy of Sciences, Kraków, Poland
| | - Andrzej J Bojarski
- Department of Medicinal Chemistry, Maj Institute of Pharmacology, Polish Academy of Sciences, Kraków, Poland
| | - Anders A Jensen
- Department of Drug Design and Pharmacology, University of Copenhagen, Copenhagen, Denmark
| | - Matthias M Herth
- Department of Drug Design and Pharmacology, University of Copenhagen, Copenhagen, Denmark
- Department of Clinical Physiology, Nuclear Medicine and PET, Copenhagen University Hospital, Copenhagen, Denmark
| | - Paul Cumming
- Department of Nuclear Medicine, Bern University Hospital, Bern, Switzerland
- School of Psychology and Counselling, Queensland University of Technology, Brisbane, QLD, Australia
| | - Agnete Overgaard
- Neurobiology Research Unit, Copenhagen University Hospital, Copenhagen, Denmark
| | - Mikael Palner
- Neurobiology Research Unit, Copenhagen University Hospital, Copenhagen, Denmark.
- Clinical Physiology and Nuclear Medicine, Department of Clinical Research, University of Southern Denmark, Odense, Denmark.
- Department of Nuclear Medicine, Odense University Hospital, Odense, Denmark.
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3
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Avendaño‐Estrada A, Verdugo‐Díaz L, Ávila‐Rodríguez M. Comparative analysis of striatal [
18
F]FDOPA uptake in a partial lesion model of Parkinson's disease in rats: ratio method versus graphical model. Synapse 2022; 76:e22231. [DOI: 10.1002/syn.22231] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Revised: 02/14/2022] [Accepted: 02/28/2022] [Indexed: 11/12/2022]
Affiliation(s)
- A. Avendaño‐Estrada
- Unidad Radiofarmacia‐Ciclotrón, División de Investigación Facultad de Medicina Universidad Nacional Autónoma de México Cd.Mx. 04510 México
| | - Leticia Verdugo‐Díaz
- Laboratorio de Biomagnetismo Departamento de Fisiología, Facultad de Medicina Universidad Nacional Autónoma de México Cd.Mx. 04510 México
| | - M.A. Ávila‐Rodríguez
- Unidad Radiofarmacia‐Ciclotrón, División de Investigación Facultad de Medicina Universidad Nacional Autónoma de México Cd.Mx. 04510 México
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Shalgunov V, Xiong M, L'Estrade ET, Raval NR, Andersen IV, Edgar FG, Speth NR, Baerentzen SL, Hansen HD, Donovan LL, Nasser A, Peitersen ST, Kjaer A, Knudsen GM, Syvänen S, Palner M, Herth MM. Blocking of efflux transporters in rats improves translational validation of brain radioligands. EJNMMI Res 2020; 10:124. [PMID: 33074370 PMCID: PMC7572968 DOI: 10.1186/s13550-020-00718-x] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2020] [Accepted: 09/24/2020] [Indexed: 11/24/2022] Open
Abstract
Background Positron emission tomography (PET) is a molecular imaging technique that can be used to investigate the in vivo pharmacology of drugs. Initial preclinical evaluation of PET tracers is often conducted in rodents due to the accessibility of disease models as well as economic considerations. Compared to larger species, rodents display a higher expression and/or activity of efflux transporters such as the P-glycoprotein (P-gp). Low brain uptake could, therefore, be species-specific and uptake in rodents not be predictive for that in humans. We hypothesized that a better prediction from rodent data could be achieved when a tracer is evaluated under P-gp inhibition. Consequently, we compared the performance of eight neuroreceptor tracers in rats with and without P-gp inhibition including a specific binding blockade. This data set was then used to predict the binding of these eight tracers in pigs. Methods PET tracers targeting serotonin 5-HT2A receptors ([18F]MH.MZ, [18F]Altanserin, [11C]Cimbi-36, [11C]Pimavanserin), serotonin 5-HT7 receptors ([11C]Cimbi-701, [11C]Cimbi-717 and [11C]BA-10) and dopamine D2/3 receptors ([18F]Fallypride) were used in the study. The brain uptake and target-specific binding of these PET radiotracers were evaluated in rats with and without inhibition of P-gp. Rat data were subsequently compared to the results obtained in pigs. Results Without P-gp inhibition, the amount of target-specific binding in the rat brain was sufficient to justify further translation for three out of eight evaluated tracers. With P-gp inhibition, results for five out of eight tracers justified further translation. The performance in pigs could correctly be predicted for six out of eight tracers when rat data obtained under P-gp inhibition were used, compared to four out of eight tracers without P-gp inhibition. Conclusions P-gp strongly affects the uptake of PET tracers in rodents, but false prediction outcomes can be reduced by evaluating a tracer under P-gp inhibition.
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Affiliation(s)
- Vladimir Shalgunov
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Jagtvej 160, 2100, Copenhagen, Denmark.,Department of Clinical Physiology, Nuclear Medicine and PET, Copenhagen University Hospital, Rigshospitalet, Blegdamsvej 9, 2100, Copenhagen, Denmark
| | - Mengfei Xiong
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Jagtvej 160, 2100, Copenhagen, Denmark.,Neurobiology Research Unit, Rigshospitalet, Blegdamsvej 9, 2100, Copenhagen, Denmark.,Department of Public Health and Caring Sciences/Geriatrics, Rudbeck Laboratory, Uppsala University, 75185, Uppsala, Sweden
| | - Elina T L'Estrade
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Jagtvej 160, 2100, Copenhagen, Denmark.,Neurobiology Research Unit, Rigshospitalet, Blegdamsvej 9, 2100, Copenhagen, Denmark.,Radiation Physics, Nuclear Medicine Physics Unit, Skånes University Hospital, Barngatan 3, 222 42, Lund, Sweden
| | - Nakul R Raval
- Neurobiology Research Unit, Rigshospitalet, Blegdamsvej 9, 2100, Copenhagen, Denmark
| | - Ida V Andersen
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Jagtvej 160, 2100, Copenhagen, Denmark.,Neurobiology Research Unit, Rigshospitalet, Blegdamsvej 9, 2100, Copenhagen, Denmark
| | - Fraser G Edgar
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Jagtvej 160, 2100, Copenhagen, Denmark
| | - Nikolaj R Speth
- Neurobiology Research Unit, Rigshospitalet, Blegdamsvej 9, 2100, Copenhagen, Denmark
| | - Simone L Baerentzen
- Neurobiology Research Unit, Rigshospitalet, Blegdamsvej 9, 2100, Copenhagen, Denmark
| | - Hanne D Hansen
- Neurobiology Research Unit, Rigshospitalet, Blegdamsvej 9, 2100, Copenhagen, Denmark.,A. A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, 149 13th Street, Charlestown, MA, 02129, USA
| | - Lene L Donovan
- Neurobiology Research Unit, Rigshospitalet, Blegdamsvej 9, 2100, Copenhagen, Denmark
| | - Arafat Nasser
- Neurobiology Research Unit, Rigshospitalet, Blegdamsvej 9, 2100, Copenhagen, Denmark
| | - Siv T Peitersen
- Neurobiology Research Unit, Rigshospitalet, Blegdamsvej 9, 2100, Copenhagen, Denmark
| | - Andreas Kjaer
- Department of Clinical Physiology, Nuclear Medicine and PET, Copenhagen University Hospital, Rigshospitalet, Blegdamsvej 9, 2100, Copenhagen, Denmark.,Cluster for Molecular Imaging, Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3, 2200, Copenhagen, Denmark
| | - Gitte M Knudsen
- Neurobiology Research Unit, Rigshospitalet, Blegdamsvej 9, 2100, Copenhagen, Denmark.,Institute of Clinical Medicine, University of Copenhagen, Blegdamsvej 3B, 2200, Copenhagen, Denmark
| | - Stina Syvänen
- Department of Public Health and Caring Sciences/Geriatrics, Rudbeck Laboratory, Uppsala University, 75185, Uppsala, Sweden
| | - Mikael Palner
- Neurobiology Research Unit, Rigshospitalet, Blegdamsvej 9, 2100, Copenhagen, Denmark.,Center for Translational Neuromedicine, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3B, 2200, Copenhagen, Denmark
| | - Matthias M Herth
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Jagtvej 160, 2100, Copenhagen, Denmark. .,Department of Clinical Physiology, Nuclear Medicine and PET, Copenhagen University Hospital, Rigshospitalet, Blegdamsvej 9, 2100, Copenhagen, Denmark.
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5
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Scott CJ, Jiao J, Melbourne A, Burgos N, Cash DM, De Vita E, Markiewicz PJ, O'Connor A, Thomas DL, Weston PS, Schott JM, Hutton BF, Ourselin S. Reduced acquisition time PET pharmacokinetic modelling using simultaneous ASL-MRI: proof of concept. J Cereb Blood Flow Metab 2019; 39:2419-2432. [PMID: 30182792 PMCID: PMC6891000 DOI: 10.1177/0271678x18797343] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Pharmacokinetic modelling on dynamic positron emission tomography (PET) data is a quantitative technique. However, the long acquisition time is prohibitive for routine clinical use. Instead, the semi-quantitative standardised uptake value ratio (SUVR) from a shorter static acquisition is used, despite its sensitivity to blood flow confounding longitudinal analysis. A method has been proposed to reduce the dynamic acquisition time for quantification by incorporating cerebral blood flow (CBF) information from arterial spin labelling (ASL) magnetic resonance imaging (MRI) into the pharmacokinetic modelling. In this work, we optimise and validate this framework for a study of ageing and preclinical Alzheimer's disease. This methodology adapts the simplified reference tissue model (SRTM) for a reduced acquisition time (RT-SRTM) and is applied to [18F]-florbetapir PET data for amyloid-β quantification. Evaluation shows that the optimised RT-SRTM can achieve amyloid burden estimation from a 30-min PET/MR acquisition which is comparable with the gold standard SRTM applied to 60 min of PET data. Conversely, SUVR showed a significantly higher error and bias, and a statistically significant correlation with tracer delivery due to the influence of blood flow. The optimised RT-SRTM produced amyloid burden estimates which were uncorrelated with tracer delivery indicating its suitability for longitudinal studies.
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Affiliation(s)
- Catherine J Scott
- Translational Imaging Group, CMIC, University College London, London, UK
| | - Jieqing Jiao
- Translational Imaging Group, CMIC, University College London, London, UK
| | - Andrew Melbourne
- Translational Imaging Group, CMIC, University College London, London, UK
| | - Ninon Burgos
- Translational Imaging Group, CMIC, University College London, London, UK.,Inria, Aramis project-team, Institut du Cerveau et de la Moelle épinière, Inserm, CNRS, Sorbonne Université, Paris, France
| | - David M Cash
- Translational Imaging Group, CMIC, University College London, London, UK.,Dementia Research Centre, Institute of Neurology, University College London, London, UK
| | - Enrico De Vita
- Neuroradiological Academic Unit, UCL Institute of Neurology, London, UK.,Lysholm Department of Neuroradiology, National Hospital for Neurology and Neurosurgery, UCL Hospitals Foundation Trust, London, UK.,Department of Biomedical Engineering, School of Biomedical Engineering & Imaging Sciences, King's College London, King's Health Partners, St Thomas' Hospital, London, UK
| | - Pawel J Markiewicz
- Translational Imaging Group, CMIC, University College London, London, UK
| | - Antoinette O'Connor
- Dementia Research Centre, Institute of Neurology, University College London, London, UK
| | - David L Thomas
- Translational Imaging Group, CMIC, University College London, London, UK.,Neuroradiological Academic Unit, UCL Institute of Neurology, London, UK.,Leonard Wolfson Experimental Neurology Centre, UCL Institute of Neurology London, UK
| | - Philip Sj Weston
- Dementia Research Centre, Institute of Neurology, University College London, London, UK
| | - Jonathan M Schott
- Dementia Research Centre, Institute of Neurology, University College London, London, UK
| | - Brian F Hutton
- Institute of Nuclear Medicine, University College London, London, UK.,Centre for Medical Radiation Physics, University of Wollongong, NSW, Australia
| | - Sébastien Ourselin
- School of Biomedical Engineering & Imaging Sciences, King's College London, London, UK
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6
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Omalu B, Small GW, Bailes J, Ercoli LM, Merrill DA, Wong KP, Huang SC, Satyamurthy N, Hammers JL, Lee J, Fitzsimmons RP, Barrio JR. Postmortem Autopsy-Confirmation of Antemortem [F-18]FDDNP-PET Scans in a Football Player With Chronic Traumatic Encephalopathy. Neurosurgery 2019; 82:237-246. [PMID: 29136240 DOI: 10.1093/neuros/nyx536] [Citation(s) in RCA: 52] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2017] [Accepted: 09/26/2017] [Indexed: 12/14/2022] Open
Abstract
Currently, only presumptive diagnosis of chronic traumatic encephalopathy (CTE) can be made in living patients. We present a modality that may be instrumental to the definitive diagnosis of CTE in living patients based on brain autopsy confirmation of [F-18]FDDNP-PET findings in an American football player with CTE. [F-18]FDDNP-PET imaging was performed 52 mo before the subject's death. Relative distribution volume parametric images and binding values were determined for cortical and subcortical regions of interest. Upon death, the brain was examined to identify the topographic distribution of neurodegenerative changes. Correlation between neuropathology and [F-18]FDDNP-PET binding patterns was performed using Spearman rank-order correlation. Mood, behavioral, motor, and cognitive changes were consistent with chronic traumatic myeloencephalopathy with a 22-yr lifetime risk exposure to American football. There were tau, amyloid, and TDP-43 neuropathological substrates in the brain with a differential topographically selective distribution. [F-18]FDDNP-PET binding levels correlated with brain tau deposition (rs = 0.59, P = .02), with highest relative distribution volumes in the parasagittal and paraventricular regions of the brain and the brain stem. No correlation with amyloid or TDP-43 deposition was observed. [F-18]FDDNP-PET signals may be consistent with neuropathological patterns of tau deposition in CTE, involving areas that receive the maximal shearing, angular-rotational acceleration-deceleration forces in American football players, consistent with distinctive and differential topographic vulnerability and selectivity of CTE beyond brain cortices, also involving midbrain and limbic areas. Future studies are warranted to determine whether differential and selective [F-18]FDDNP-PET may be useful in establishing a diagnosis of CTE in at-risk patients.
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Affiliation(s)
- Bennet Omalu
- Department of Medical Pathology and Laboratory Medicine, School of Medicine, University of California, Davis, Sacramento, California
| | - Gary W Small
- Department of Psychiatry and Biobehavioral Sciences, Semel Institute for Neuroscience and Human Behavior, The David Geffen School of Medicine, University of California, Los Angeles, California
| | - Julian Bailes
- Department of Neurosurgery, North Shore University Health System and University of Chicago Pritzker School of Medicine, Evanston, Illinois
| | - Linda M Ercoli
- Department of Psychiatry and Biobehavioral Sciences, Semel Institute for Neuroscience and Human Behavior, The David Geffen School of Medicine, University of California, Los Angeles, California
| | - David A Merrill
- Department of Psychiatry and Biobehavioral Sciences, Semel Institute for Neuroscience and Human Behavior, The David Geffen School of Medicine, University of California, Los Angeles, California
| | - Koon-Pong Wong
- Department of Molecular and Medical Pharmacology, The David Geffen School of Medicine, University of California, Los Angeles, California
| | - Sung-Cheng Huang
- Department of Molecular and Medical Pharmacology, The David Geffen School of Medicine, University of California, Los Angeles, California
| | - Nagichettiar Satyamurthy
- Department of Molecular and Medical Pharmacology, The David Geffen School of Medicine, University of California, Los Angeles, California
| | | | - John Lee
- Department of Pathology, North Shore University Health System and University of Chicago Pritzker School of Medicine, Evanston, Illinois
| | | | - Jorge R Barrio
- Department of Molecular and Medical Pharmacology, The David Geffen School of Medicine, University of California, Los Angeles, California
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8
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Bærentzen S, Casado-Sainz A, Lange D, Shalgunov V, Tejada IM, Xiong M, L'Estrade ET, Edgar FG, Lee H, Herth MM, Palner M. The Chemogenetic Receptor Ligand Clozapine N-Oxide Induces in vivo Neuroreceptor Occupancy and Reduces Striatal Glutamate Levels. Front Neurosci 2019; 13:187. [PMID: 31001069 PMCID: PMC6456655 DOI: 10.3389/fnins.2019.00187] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2018] [Accepted: 02/15/2019] [Indexed: 12/24/2022] Open
Abstract
Chemogenetic studies with the ligand clozapine N-oxide (CNO) are predicated upon the assumption that CNO is devoid of actions at natural neuroreceptors. However, recent evidence shows that CNO may be converted back to clozapine (CLZ) in vivo, which could yield plasma concentrations that may be sufficient to occupy inter alia dopamine D2/3 and serotonin 5HT2A receptors in living brain. To test this phenomenon, we measured striatal dopamine D2/3 receptor occupancy with [18F]fallypride PET and serotonin 5HT2A occupancy ex vivo using [18F]MH.MZ. We found a CNO dose-dependent effect on the availability of both neuroreceptor sites. In parallel MR spectroscopy experiments, we found that CNO reduced creatine + phosphcreatine (Cr+PCr) and increased N-acetylaspartate + N-acetylaspartylglutamate (NAA+NAAG) signals in the prefrontal cortex, and also reduced the glutamate signal in dorsal striatum, with peak effect at 2 mg/kg. Thus, our findings suggest that conversion of CNO to CLZ in living rats imparts significant occupancy at endogenous neuroreceptors and significant changes to neurometabolite levels.
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Affiliation(s)
- Simone Bærentzen
- Neurobiology Research Unit, Copenhagen University Hospital, Copenhagen, Denmark.,Center for Translational Neuromedicine, University of Copenhagen, Copenhagen, Denmark
| | - Agata Casado-Sainz
- Neurobiology Research Unit, Copenhagen University Hospital, Copenhagen, Denmark
| | - Denise Lange
- Neurobiology Research Unit, Copenhagen University Hospital, Copenhagen, Denmark.,Institute of Aerospace Medicine, German Aerospace Center (DLR), Cologne, Germany
| | - Vladimir Shalgunov
- Department of Drug Design and Pharmacology, University of Copenhagen, Copenhagen, Denmark
| | | | - Mengfei Xiong
- Neurobiology Research Unit, Copenhagen University Hospital, Copenhagen, Denmark.,Department of Drug Design and Pharmacology, University of Copenhagen, Copenhagen, Denmark
| | - Elina T L'Estrade
- Neurobiology Research Unit, Copenhagen University Hospital, Copenhagen, Denmark.,Department of Drug Design and Pharmacology, University of Copenhagen, Copenhagen, Denmark.,Radiation Physics, Nuclear Medicine Physics Unit, Skånes University Hospital, Lund, Sweden
| | - Fraser G Edgar
- Department of Drug Design and Pharmacology, University of Copenhagen, Copenhagen, Denmark
| | - Hedok Lee
- Department of Anesthesiology and Pediatric Anesthesiology, Yale University, New Haven, CT, United States
| | - Matthias M Herth
- Neurobiology Research Unit, Copenhagen University Hospital, Copenhagen, Denmark.,Department of Drug Design and Pharmacology, University of Copenhagen, Copenhagen, Denmark.,Department of Clinical Physiology, Nuclear Medicine and PET, Copenhagen University Hospital, Copenhagen, Denmark
| | - Mikael Palner
- Neurobiology Research Unit, Copenhagen University Hospital, Copenhagen, Denmark.,Center for Translational Neuromedicine, University of Copenhagen, Copenhagen, Denmark
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9
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Zhang X, Liu F, Knapp KA, Nickels ML, Manning HC, Bellan LM. A simple microfluidic platform for rapid and efficient production of the radiotracer [ 18F]fallypride. LAB ON A CHIP 2018; 18:1369-1377. [PMID: 29658049 DOI: 10.1039/c8lc00167g] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Herein, we report the development of a simple, high-throughput and efficient microfluidic system for synthesizing radioactive [18F]fallypride, a PET imaging radiotracer widely used in medical research. The microfluidic chip contains all essential modules required for the synthesis and purification of radioactive fallypride. The radiochemical yield of the tracer is sufficient for multiple animal injections for preclinical imaging studies. To produce the on-chip concentration and purification columns, we employ a simple "trapping" mechanism by inserting rows of square pillars with predefined gaps near the outlet of microchannel. Microspheres with appropriate functionality are suspended in solution and loaded into the microchannels to form columns for radioactivity concentration and product purification. Instead of relying on complicated flow control elements (e.g., micromechanical valves requiring complex external pneumatic actuation), external valves are utilized to control transfer of the reagents between different modules. The on-chip ion exchange column can efficiently capture [18F]fluoride with negligible loss (∼98% trapping efficiency), and subsequently release a burst of concentrated [18F]fluoride to the reaction cavity. A thin layer of PDMS with a small hole in the center facilitates rapid and reliable water evaporation (with the aid of azeotropic distillation and nitrogen flow) while reducing fluoride loss. During the solvent exchange and fluorination reaction, the entire chip is uniformly heated to the desired temperature using a hot plate. All aspects of the [18F]fallypride synthesis were monitored by high-performance liquid chromatography (HPLC) analysis, resulting in labelling efficiency in fluorination reaction ranging from 67-87% (n = 5). Moreover, after isolating unreacted [18F]fluoride, remaining fallypride precursor, and various by-products via an on-chip purification column, the eluted [18F]fallypride is radiochemically pure and of a sufficient quantity to allow for PET imaging (∼5 mCi). Finally, a positron emission tomography (PET) image of a rat brain injected with ∼300 μCi [18F]fallypride produced by our microfluidic chip is provided, demonstrating the utility of the product produced by the microfluidic reactor. With a short synthesis time (∼60 min) and a highly integrated on-chip modular configuration that allows for concentration, reaction, and product purification, our microfluidic chip offers numerous exciting advantages with the potential for applications in radiochemical research and clinical production. Moreover, due to its simplicity and potential for automation, we anticipate it may be easily integrated into a clinical environment.
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Affiliation(s)
- Xin Zhang
- Department of Mechanical Engineering, Vanderbilt University, Nashville, TN 37235, USA
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10
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Barry RL, Byun NE, Williams JM, Siuta MA, Tantawy MN, Speed NK, Saunders C, Galli A, Niswender KD, Avison MJ. Brief exposure to obesogenic diet disrupts brain dopamine networks. PLoS One 2018; 13:e0191299. [PMID: 29698491 PMCID: PMC5919534 DOI: 10.1371/journal.pone.0191299] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2017] [Accepted: 01/02/2018] [Indexed: 11/26/2022] Open
Abstract
Objective We have previously demonstrated that insulin signaling, through the downstream signaling kinase Akt, is a potent modulator of dopamine transporter (DAT) activity, which fine-tunes dopamine (DA) signaling at the synapse. This suggests a mechanism by which impaired neuronal insulin receptor signaling, a hallmark of diet-induced obesity, may contribute to impaired DA transmission. We tested whether a short-term (two-week) obesogenic high-fat (HF) diet could reduce striatal Akt activity, a marker of central insulin, receptor signaling and blunt striatal and dopaminergic network responsiveness to amphetamine (AMPH). Methods We examined the effects of a two-week HF diet on striatal DAT activity in rats, using AMPH as a probe in a functional magnetic resonance imaging (fMRI) assay, and mapped the disruption in AMPH-evoked functional connectivity between key dopaminergic targets and their projection areas using correlation and permutation analyses. We used phosphorylation of the Akt substrate GSK3α in striatal extracts as a measure of insulin receptor signaling. Finally, we confirmed the impact of HF diet on striatal DA D2 receptor (D2R) availability using [18F]fallypride positron emission tomography (PET). Results We found that rats fed a HF diet for only two weeks have reductions in striatal Akt activity, a marker of decreased striatal insulin receptor signaling and blunted striatal responsiveness to AMPH. HF feeding also reduced interactions between elements of the mesolimbic (nucleus accumbens–anterior cingulate) and sensorimotor circuits (caudate/putamen–thalamus–sensorimotor cortex) implicated in hedonic feeding. D2R availability was reduced in HF-fed animals. Conclusion These studies support the hypothesis that central insulin signaling and dopaminergic neurotransmission are already altered after short-term HF feeding. Because AMPH induces DA efflux and brain activation, in large part via DAT, these findings suggest that blunted central nervous system insulin receptor signaling through a HF diet can impair DA homeostasis, thereby disrupting cognitive and reward circuitry involved in the regulation of hedonic feeding.
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Affiliation(s)
- Robert L. Barry
- Vanderbilt University Institute of Imaging Science, Vanderbilt University Medical Center, Nashville, Tennessee, United States of America
| | - Nellie E. Byun
- Vanderbilt University Institute of Imaging Science, Vanderbilt University Medical Center, Nashville, Tennessee, United States of America
- Department of Radiology and Radiological Sciences, Vanderbilt University Medical Center, Nashville, Tennessee, United States of America
- Department of Pharmacology, Vanderbilt University Medical Center, Nashville, Tennessee, United States of America
- * E-mail:
| | - Jason M. Williams
- Vanderbilt University Institute of Imaging Science, Vanderbilt University Medical Center, Nashville, Tennessee, United States of America
- Department of Radiology and Radiological Sciences, Vanderbilt University Medical Center, Nashville, Tennessee, United States of America
| | - Michael A. Siuta
- Vanderbilt University Institute of Imaging Science, Vanderbilt University Medical Center, Nashville, Tennessee, United States of America
- Department of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee, United States of America
| | - Mohammed N. Tantawy
- Vanderbilt University Institute of Imaging Science, Vanderbilt University Medical Center, Nashville, Tennessee, United States of America
- Department of Radiology and Radiological Sciences, Vanderbilt University Medical Center, Nashville, Tennessee, United States of America
| | - Nicole K. Speed
- Department of Molecular Physiology and Biophysics, Vanderbilt University Medical Center, Nashville, Tennessee, United States of America
| | - Christine Saunders
- Department of Pharmacology, Vanderbilt University Medical Center, Nashville, Tennessee, United States of America
| | - Aurelio Galli
- Department of Pharmacology, Vanderbilt University Medical Center, Nashville, Tennessee, United States of America
- Department of Molecular Physiology and Biophysics, Vanderbilt University Medical Center, Nashville, Tennessee, United States of America
- Vanderbilt Brain Institute, Vanderbilt University Medical Center, Nashville, Tennessee, United States of America
- Department of Psychiatry, Vanderbilt University Medical Center, Nashville, Tennessee, United States of America
| | - Kevin D. Niswender
- Department of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee, United States of America
- Department of Molecular Physiology and Biophysics, Vanderbilt University Medical Center, Nashville, Tennessee, United States of America
- Vanderbilt Brain Institute, Vanderbilt University Medical Center, Nashville, Tennessee, United States of America
- Tennessee Valley Healthcare System, Nashville, Tennessee, United States of America
| | - Malcolm J. Avison
- Vanderbilt University Institute of Imaging Science, Vanderbilt University Medical Center, Nashville, Tennessee, United States of America
- Department of Radiology and Radiological Sciences, Vanderbilt University Medical Center, Nashville, Tennessee, United States of America
- Department of Pharmacology, Vanderbilt University Medical Center, Nashville, Tennessee, United States of America
- Vanderbilt Brain Institute, Vanderbilt University Medical Center, Nashville, Tennessee, United States of America
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11
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Mutual activation of glutamatergic mGlu 4 and muscarinic M 4 receptors reverses schizophrenia-related changes in rodents. Psychopharmacology (Berl) 2018; 235:2897-2913. [PMID: 30054675 PMCID: PMC6182605 DOI: 10.1007/s00213-018-4980-y] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/14/2017] [Accepted: 07/17/2018] [Indexed: 02/05/2023]
Abstract
RATIONALE Metabotropic glutamate receptors and muscarinic M4 receptors have been proposed as novel targets for various brain disorders, including schizophrenia. Both receptors are coupled to Go/i proteins and are expressed in brain circuits that are important in schizophrenia. Therefore, their mutual activation may be an effective treatment and allow minimizing the doses of ligands required for optimal activity. OBJECTIVES In the present studies, subactive doses of mGlu4 and M4 activators (LSP4-2022 and VU152100, respectively) were administered to investigate the mutual interaction between mGlu4 and M4 receptors in animal models of schizophrenia. METHODS The behavioral tests used were MK-801-induced hyperactivity, (±)-2.5-dimethoxy-4-iodoamphetamine hydrochloride (DOI)-induced head twitches, the modified forced swim test, and MK-801-induced disruptions of social interactions and novel object recognition. DOI-induced spontaneous excitatory postsynaptic currents (sEPSCs) in brain slices and positron emission tomography (PET) in were used to establish the ability of these compounds to modulate the glutamatergic and dopaminergic systems. Rotarod was used to assess putative adverse effects. RESULTS The mutual administration of subactive doses of LSP4-2022 and VU152100 exerted similar antipsychotic-like efficacy in animals as observed for active doses of both compounds, indicating their additive actions. VU152100 inhibited the DOI-induced frequency (but not amplitude) of sEPSCs in the frontal cortex, confirming presynaptic regulation of glutamate release. Both compounds reversed amphetamine-induced decrease in D2 receptor levels in the striatum, as measured with [18F]fallypride. The compounds did not induce any motor impartments when measured in rotarod test. CONCLUSIONS Based on our results, the simultaneous activation of M4 and mGlu4 receptors is beneficial in reversing MK-801- and amphetamine-induced schizophrenia-related changes in animals.
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Elliott JT, Samkoe KS, Davis SC, Gunn JR, Paulsen KD, Roberts DW, Pogue BW. Image-derived arterial input function for quantitative fluorescence imaging of receptor-drug binding in vivo. JOURNAL OF BIOPHOTONICS 2016; 9:282-95. [PMID: 26349671 PMCID: PMC5313240 DOI: 10.1002/jbio.201500162] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/27/2015] [Revised: 08/18/2015] [Accepted: 08/19/2015] [Indexed: 05/30/2023]
Abstract
Receptor concentration imaging (RCI) with targeted-untargeted optical dye pairs has enabled in vivo immunohistochemistry analysis in preclinical subcutaneous tumors. Successful application of RCI to fluorescence guided resection (FGR), so that quantitative molecular imaging of tumor-specific receptors could be performed in situ, would have a high impact. However, assumptions of pharmacokinetics, permeability and retention, as well as the lack of a suitable reference region limit the potential for RCI in human neurosurgery. In this study, an arterial input graphic analysis (AIGA) method is presented which is enabled by independent component analysis (ICA). The percent difference in arterial concentration between the image-derived arterial input function (AIFICA ) and that obtained by an invasive method (ICACAR ) was 2.0 ± 2.7% during the first hour of circulation of a targeted-untargeted dye pair in mice. Estimates of distribution volume and receptor concentration in tumor bearing mice (n = 5) recovered using the AIGA technique did not differ significantly from values obtained using invasive AIF measurements (p = 0.12). The AIGA method, enabled by the subject-specific AIFICA , was also applied in a rat orthotopic model of U-251 glioblastoma to obtain the first reported receptor concentration and distribution volume maps during open craniotomy.
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Affiliation(s)
- Jonathan T Elliott
- Thayer School of Engineering, Dartmouth College, Hanover, NH, 03755, USA.
| | - Kimberley S Samkoe
- Department of Surgery, Geisel School of Medicine at Dartmouth, Lebanon, NH, 03756, USA
| | - Scott C Davis
- Thayer School of Engineering, Dartmouth College, Hanover, NH, 03755, USA
| | - Jason R Gunn
- Thayer School of Engineering, Dartmouth College, Hanover, NH, 03755, USA
| | - Keith D Paulsen
- Thayer School of Engineering, Dartmouth College, Hanover, NH, 03755, USA
| | - David W Roberts
- Department of Surgery, Geisel School of Medicine at Dartmouth, Lebanon, NH, 03756, USA
- Section of Neurosurgery, Dartmouth-Hitchcock Medical Center, Lebanon, NH, 03756, USA
| | - Brian W Pogue
- Thayer School of Engineering, Dartmouth College, Hanover, NH, 03755, USA
- Department of Surgery, Geisel School of Medicine at Dartmouth, Lebanon, NH, 03756, USA
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Fa YH, Ni JQ, Wu XJ, Tan JQ, Wu YW. Evaluation of the early response and mechanism of treatment of Parkinson's disease with L-dopa using 18F-fallypride micro-positron emission tomography scanning. Exp Ther Med 2015; 11:101-109. [PMID: 26889225 PMCID: PMC4726873 DOI: 10.3892/etm.2015.2900] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2015] [Accepted: 05/29/2015] [Indexed: 11/05/2022] Open
Abstract
The aim of the present study was to investigate the use of 18F-fallypride micro-positron emission tomography (micro-PET) imaging in the evaluation of the early therapeutic efficacy of L-dopa in the treatment of Parkinson's disease (PD) and the underlying mechanism. 18F-fallypride was synthesized and its specific binding with dopamine (DA) receptors in normal mouse brain was studied. Following the establishment of a mouse model of PD, the animals were divided into normal control, PD model and L-dopa treatment groups. General behavior, swimming test, locomotor activity counts, transmission electron microscopy, immunohistochemical analysis, high performance liquid chromatography-electrochemical detection and 18F-fallypride micro-PET imaging were used to study intergroup differences and the correlation between the changes of striatal uptake of 18F-fallypride and the therapeutic efficacy. The general behavioral features of PD model mice were similar to the clinical symptoms of PD patients and were alleviated after treatment. The swimming time, locomotor activity and frequency of standing posture of PD model mice were lower than those of the control mice, but had no difference from those of the control mice after L-dopa treatment. The number of tyrosine hydroxylase-positive neurons and the striatal contents of glutathione peroxidase, superoxide dismutase, DA and its metabolites 3,5-dihydroxyphenylacetic acid and homovanillic acid in the PD group were lower than those in the control group, but were significantly improved following the treatment; the significant reduction in DOPAC/DA and HVA/DA ratios post treatment suggested that the rate of DA metabolism decreased significantly. The striatal malondialdehyde content in the PD group increased compared with that in the control group, but was reduced after L-dopa treatment. Micro-PET imaging indicated that the uptake of 18F-fallypride in the mouse striatum of the PD group was lower than that of the control group and was significantly increased after the treatment. The mechanism of treatment of PD with L-dopa in mice may involve increasing the number of TH-positive cells and DA receptor levels, as well as reducing the rate of DA metabolism; such changes can be noninvasively observed in vitro by 18F-fallypride imaging.
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Affiliation(s)
- Yi-Hua Fa
- School of Radiation Medicine and Protection, Medical College of Soochow University, Suzhou, Jiangsu 215000, P.R. China
| | - Jian-Qiang Ni
- Department of Neurology, The First Affiliated Hospital of Soochow University, Suzhou, Jiangsu 215006, P.R. China
| | - Xiao-Jin Wu
- Department of Hematology, The First Affiliated Hospital of Soochow University, Suzhou, Jiangsu 215006, P.R. China
| | - Jia-Qing Tan
- Department of Nuclear Medicine, The First Affiliated Hospital of Soochow University, Suzhou, Jiangsu 215006, P.R. China
| | - Yi-Wei Wu
- School of Radiation Medicine and Protection, Medical College of Soochow University, Suzhou, Jiangsu 215000, P.R. China; Department of Nuclear Medicine, The First Affiliated Hospital of Soochow University, Suzhou, Jiangsu 215006, P.R. China
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de Witte WEA, Wong YC, Nederpelt I, Heitman LH, Danhof M, van der Graaf PH, Gilissen RAHJ, de Lange ECM. Mechanistic models enable the rational use of in vitro drug-target binding kinetics for better drug effects in patients. Expert Opin Drug Discov 2015; 11:45-63. [PMID: 26484747 DOI: 10.1517/17460441.2016.1100163] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
INTRODUCTION Drug-target binding kinetics are major determinants of the time course of drug action for several drugs, as clearly described for the irreversible binders omeprazole and aspirin. This supports the increasing interest to incorporate newly developed high-throughput assays for drug-target binding kinetics in drug discovery. A meaningful application of in vitro drug-target binding kinetics in drug discovery requires insight into the relation between in vivo drug effect and in vitro measured drug-target binding kinetics. AREAS COVERED In this review, the authors discuss both the relation between in vitro and in vivo measured binding kinetics and the relation between in vivo binding kinetics, target occupancy and effect profiles. EXPERT OPINION More scientific evidence is required for the rational selection and development of drug-candidates on the basis of in vitro estimates of drug-target binding kinetics. To elucidate the value of in vitro binding kinetics measurements, it is necessary to obtain information on system-specific properties which influence the kinetics of target occupancy and drug effect. Mathematical integration of this information enables the identification of drug-specific properties which lead to optimal target occupancy and drug effect in patients.
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Affiliation(s)
- Wilhelmus E A de Witte
- a Division of Pharmacology, Leiden Academic Centre for Drug Research , Leiden University , Einsteinweg 55, 2333 CC Leiden , The Netherlands
| | - Yin Cheong Wong
- a Division of Pharmacology, Leiden Academic Centre for Drug Research , Leiden University , Einsteinweg 55, 2333 CC Leiden , The Netherlands
| | - Indira Nederpelt
- b Division of Medicinal Chemistry, Leiden Academic Centre for Drug Research , Leiden University , Einsteinweg 55, 2333 CC Leiden , The Netherlands
| | - Laura H Heitman
- b Division of Medicinal Chemistry, Leiden Academic Centre for Drug Research , Leiden University , Einsteinweg 55, 2333 CC Leiden , The Netherlands
| | - Meindert Danhof
- a Division of Pharmacology, Leiden Academic Centre for Drug Research , Leiden University , Einsteinweg 55, 2333 CC Leiden , The Netherlands
| | - Piet H van der Graaf
- a Division of Pharmacology, Leiden Academic Centre for Drug Research , Leiden University , Einsteinweg 55, 2333 CC Leiden , The Netherlands
| | - Ron A H J Gilissen
- c A Division of Janssen Pharmaceutica N.V., Janssen Research and Development , Turnhoutseweg 30, Beerse 2340 , Belgium
| | - Elizabeth C M de Lange
- a Division of Pharmacology, Leiden Academic Centre for Drug Research , Leiden University , Einsteinweg 55, 2333 CC Leiden , The Netherlands
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Mukherjee J, Constantinescu CC, Hoang AT, Jerjian T, Majji D, Pan ML. Dopamine D3 receptor binding of (18)F-fallypride: Evaluation using in vitro and in vivo PET imaging studies. Synapse 2015; 69:577-91. [PMID: 26422464 DOI: 10.1002/syn.21867] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2015] [Revised: 08/25/2015] [Accepted: 09/19/2015] [Indexed: 12/17/2022]
Abstract
Identification of dopamine D3 receptors (D3R) in vivo is important to understand several brain functions related to addiction. The goal of this work was to identify D3R binding of the dopamine D2 receptor (D2R)/D3R imaging agent, (18)F-fallypride. Brain slices from male Sprague-Dawley rats (n = 6) and New Zealand White rabbits (n = 6) were incubated with (18)F-fallypride and D3R selective agonist (R)-7-OH-DPAT (98-fold D3R selective). Rat slices were also treated with BP 897 (68-fold D3R selective partial agonist) and NGB 2904 (56-fold D3R selective antagonist). In vivo rat studies (n = 6) were done on Inveon PET using 18-37 MBq (18)F-fallypride and drug-induced displacement by (R)-7-OH-DPAT, BP 897 and NGB 2904. PET/CT imaging of wild type (WT, n = 2) and D2R knock-out (KO, n = 2) mice were carried out with (18)F-fallypride. (R)-7-OH-DPAT displaced binding of (18)F-fallypride, both in vitro and in vivo. In vitro, at 10 nM (R)-7-OH-DPAT, (18)F-fallypride binding in the rat ventral striatum (VST) and dorsal striatum (DST) and rabbit nucleus accumbens were reduced by ∼10-15%. At 10 μM (R)-7-OH-DPAT all regions in rat and rabbit were reduced by ≥85%. In vivo reductions for DST and VST before and after (R)-7-OH-DPAT were: low-dose (0.015 mg kg(-1)) DST -22%, VST -29%; high-dose (1.88 mg kg(-1)) DST -58%, VST -77%, suggesting D3R/D2R displacement. BP 897 and NGB 2904 competed with (18)F-fallypride in vitro, but unlike BP 897, NGB 2904 did not displace (18)F-fallypride in vivo. The D2R KO mice lacked (18)F-fallypride binding in the DST. In summary, our findings suggest that up to 20% of (18)F-fallypride may be bound to D3R sites in vivo.
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Affiliation(s)
- Jogeshwar Mukherjee
- Department of Radiological Sciences, Preclinical Imaging, University of California, Irvine, California, 92697
| | - Cristian C Constantinescu
- Department of Radiological Sciences, Preclinical Imaging, University of California, Irvine, California, 92697
| | - Angela T Hoang
- Department of Radiological Sciences, Preclinical Imaging, University of California, Irvine, California, 92697
| | - Taleen Jerjian
- Department of Radiological Sciences, Preclinical Imaging, University of California, Irvine, California, 92697
| | - Divya Majji
- Department of Radiological Sciences, Preclinical Imaging, University of California, Irvine, California, 92697
| | - Min-Liang Pan
- Department of Radiological Sciences, Preclinical Imaging, University of California, Irvine, California, 92697
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Ota M, Ogawa S, Kato K, Wakabayashi C, Kunugi H. Methamphetamine-sensitized rats show augmented dopamine release to methylphenidate stimulation: a positron emission tomography using [18F]fallypride. Psychiatry Res 2015; 232:92-7. [PMID: 25703679 DOI: 10.1016/j.pscychresns.2015.01.023] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/08/2014] [Revised: 10/10/2014] [Accepted: 01/28/2015] [Indexed: 12/23/2022]
Abstract
Previous studies demonstrated that patients with schizophrenia show greater sensitivity to psychostimulants than healthy subjects. Sensitization to psychostimulants and resultant alteration of dopaminergic neurotransmission in rodents have been suggested as a useful model of schizophrenia. This study was aimed to examine the use of methylphenidate as a psychostimulant to induce dopamine release and that of [18F]fallypride as a radioligand to estimate the release in a rat model of schizophrenia. Six rats were scanned by positron emission tomography (PET) twice before and after methylphenidate challenge to evaluate dopamine release. After the scans, these rats were sensitized by using repeated methamphetamine (MAP) administration. Then, they were re-scanned twice again before and after methylphenidate challenge to evaluate whether MAP-sensitized rats show greater sensitivity to methylphenidate. We revealed a main effect of MAP-pretreatment and that of metylphenidate challenge. We found that % change of distribution volume ratio after repeated administration of MAP was greater than that before sensitization. These results suggest that methylphenidate-induced striatal dopamine release increased after sensitization to MAP. PET scan using [18F]fallypride at methylphenidate-challenge may provide a biological marker for schizophrenia and be useful to diagnose schizophrenia.
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Affiliation(s)
- Miho Ota
- Department of Mental Disorder Research, National Institute of Neuroscience, National Center of Neurology and Psychiatry4-1-1 Ogawa-Higashi, KodairaTokyo187-8502, Japan.
| | - Shintaro Ogawa
- Department of Mental Disorder Research, National Institute of Neuroscience, National Center of Neurology and Psychiatry4-1-1 Ogawa-Higashi, KodairaTokyo187-8502, Japan
| | - Koichi Kato
- Organic Radiochemistry Section, Department of Advanced Neuroimaging, Integrative Brain Imaging Center, National Center Hospital of Neurology and Psychiatry, 4-1-1 Ogawa-Higashi, Kodaira, Tokyo 187-8502, Japan
| | - Chisato Wakabayashi
- Department of Mental Disorder Research, National Institute of Neuroscience, National Center of Neurology and Psychiatry4-1-1 Ogawa-Higashi, KodairaTokyo187-8502, Japan
| | - Hiroshi Kunugi
- Department of Mental Disorder Research, National Institute of Neuroscience, National Center of Neurology and Psychiatry4-1-1 Ogawa-Higashi, KodairaTokyo187-8502, Japan
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In vivo characterization of chronic traumatic encephalopathy using [F-18]FDDNP PET brain imaging. Proc Natl Acad Sci U S A 2015; 112:E2039-47. [PMID: 25848027 DOI: 10.1073/pnas.1409952112] [Citation(s) in RCA: 137] [Impact Index Per Article: 15.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Chronic traumatic encephalopathy (CTE) is an acquired primary tauopathy with a variety of cognitive, behavioral, and motor symptoms linked to cumulative brain damage sustained from single, episodic, or repetitive traumatic brain injury (TBI). No definitive clinical diagnosis for this condition exists. In this work, we used [F-18]FDDNP PET to detect brain patterns of neuropathology distribution in retired professional American football players with suspected CTE (n = 14) and compared results with those of cognitively intact controls (n = 28) and patients with Alzheimer's dementia (AD) (n = 24), a disease that has been cognitively associated with CTE. [F-18]FDDNP PET imaging results in the retired players suggested the presence of neuropathological patterns consistent with models of concussion wherein brainstem white matter tracts undergo early axonal damage and cumulative axonal injuries along subcortical, limbic, and cortical brain circuitries supporting mood, emotions, and behavior. This deposition pattern is distinctively different from the progressive pattern of neuropathology [paired helical filament (PHF)-tau and amyloid-β] in AD, which typically begins in the medial temporal lobe progressing along the cortical default mode network, with no or minimal involvement of subcortical structures. This particular [F-18]FDDNP PET imaging pattern in cases of suspected CTE also is primarily consistent with PHF-tau distribution observed at autopsy in subjects with a history of mild TBI and autopsy-confirmed diagnosis of CTE.
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Lee DE, Reid WC, Ibrahim WG, Peterson KL, Lentz MR, Maric D, Choyke PL, Jagoda EM, Hammoud DA. Imaging dopaminergic dysfunction as a surrogate marker of neuropathology in a small-animal model of HIV. Mol Imaging 2015; 13. [PMID: 25248756 DOI: 10.2310/7290.2014.00031] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The dopaminergic system is especially vulnerable to the effects of human immunodeficiency virus (HIV) infection, rendering dopaminergic deficits early surrogate markers of HIV-associated neuropathology. We quantified dopamine D2/3 receptors in young HIV-1 transgenic (Tg) (n = 6) and age-matched control rats (n = 7) and adult Tg (n = 5) and age-matched control rats (n = 5) using [18F]fallypride positron emission tomography (PET). Regional uptake was quantified as binding potential (BPND) using the two-tissue reference model with the cerebellum as the reference. Time-activity curves were generated for the ventral striatum, dorsal striatum, thalamus, and cerebellum. Whereas BPND values were significantly lower in the ventral striatum (p < .001) and dorsal striatum (p = .001) in the adult Tg rats compared to controls rats, they were significantly lower only in the dorsal striatum (p < .05) in the young rats. Tg rats had smaller striatal volumes on magnetic resonance imaging. We also found lower expression levels of tyrosine hydroxylase on immunohistochemistry in the Tg animals. Our findings suggest that progressive striatal D2/3 receptor deficits occur in Tg rats as they age and can be detected using small-animal PET imaging. The effectiveness of various approaches in preventing or halting this dopaminergic loss in the Tg rat can thus be measured preclinically using [18F]fallypride PET as a molecular imaging biomarker of HIV-associated neuropathology.
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Tsartsalis S, Moulin-Sallanon M, Dumas N, Tournier BB, Ginovart N, Millet P. A Modified Simplified Reference Tissue Model for the Quantification of Dopamine D2/3Receptors with [18F]Fallypride Images. Mol Imaging 2014; 13. [DOI: 10.2310/7290.2014.00028] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Affiliation(s)
- Stergios Tsartsalis
- From the Vulnerability Biomarkers Unit, Division of General Psychiatry, Department of Psychiatry, University Hospitals of Geneva, Geneva, Switzerland; Department of Psychiatry, University of Geneva, Geneva, Switzerland; and INSERM Unit 1039, J. Fourier University, La Tronche, France
| | - Marcelle Moulin-Sallanon
- From the Vulnerability Biomarkers Unit, Division of General Psychiatry, Department of Psychiatry, University Hospitals of Geneva, Geneva, Switzerland; Department of Psychiatry, University of Geneva, Geneva, Switzerland; and INSERM Unit 1039, J. Fourier University, La Tronche, France
| | - Noé Dumas
- From the Vulnerability Biomarkers Unit, Division of General Psychiatry, Department of Psychiatry, University Hospitals of Geneva, Geneva, Switzerland; Department of Psychiatry, University of Geneva, Geneva, Switzerland; and INSERM Unit 1039, J. Fourier University, La Tronche, France
| | - Benjamin B. Tournier
- From the Vulnerability Biomarkers Unit, Division of General Psychiatry, Department of Psychiatry, University Hospitals of Geneva, Geneva, Switzerland; Department of Psychiatry, University of Geneva, Geneva, Switzerland; and INSERM Unit 1039, J. Fourier University, La Tronche, France
| | - Nathalie Ginovart
- From the Vulnerability Biomarkers Unit, Division of General Psychiatry, Department of Psychiatry, University Hospitals of Geneva, Geneva, Switzerland; Department of Psychiatry, University of Geneva, Geneva, Switzerland; and INSERM Unit 1039, J. Fourier University, La Tronche, France
| | - Philippe Millet
- From the Vulnerability Biomarkers Unit, Division of General Psychiatry, Department of Psychiatry, University Hospitals of Geneva, Geneva, Switzerland; Department of Psychiatry, University of Geneva, Geneva, Switzerland; and INSERM Unit 1039, J. Fourier University, La Tronche, France
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Millet P, Moulin-Sallanon M, Tournier BB, Dumas N, Charnay Y, Ibáñez V, Ginovart N. Quantification of dopamine D(2/3) receptors in rat brain using factor analysis corrected [18F]Fallypride images. Neuroimage 2012; 62:1455-68. [PMID: 22659483 DOI: 10.1016/j.neuroimage.2012.05.075] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2012] [Revised: 04/20/2012] [Accepted: 05/26/2012] [Indexed: 11/15/2022] Open
Abstract
The goal of this work is to quantify the binding parameters of [(18)F]Fallypride in the striatal and extrastriatal regions of the rat brain using factor analysis (FA) to correct small animal PET kinetic imaging for spillover defluorination radioactivity. Eleven rats were employed for YAP-(S)PET acquisitions and metabolite studies. All kinetic parameters including B'(max) and K(d)V(R) were estimated with a three-tissue compartment seven-parameter model (3T-7k) on the basis of all the FA-corrected data from the multi-injection protocol. Binding potential (BP(ND)) was calculated with Logan's graphical analysis taking cerebellum as the reference region and using the first injection raw (BP(ND-RAW)) and FA-corrected (BP(ND-FA)) data. Three distinct factors corresponding to free+non-specific binding, specific binding and skull and gland accumulation were recovered from FA with their corresponding spatial distributions. The resulting reconstructed images without skull and gland accumulation were improved to provide a better contrast between specific and non-specific regions. Very bad fits were obtained when using time-activity curves (TACs) calculated from the raw [(18)F]Fallypride data, whereas all TACs were well fitted by the 3T-7k model after FA correction. FA-corrected data enables the cerebellar region to be used as reference for the Logan approach. The magnitude of the BP(ND-FA) values was increased from 21% to 108% across regions and the rank order of BP(ND-FA) values (Cx<Hip<MB≈Thal<VST<DST) matched those of B'(max) values. This [(18)F]Fallypride study in rats shows that all brain regions are contaminated by skull and gland radioactivity accumulation. We show that FA is a very effective method of correcting kinetic data for spillover activity. Moreover, the approach presented here with [(18)F]Fallypride data can be extended to other radioligands and also to human data which can be highly distorted by radiodefluorination as shown in the literature.
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Affiliation(s)
- Philippe Millet
- Clinical Neurophysiology and Neuroimaging Unit, Division of Neuropsychiatry, Department of Psychiatry, University Hospitals of Geneva, Switzerland.
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Johnson KA, Jones CK, Tantawy MN, Bubser M, Marvanova M, Ansari MS, Baldwin RM, Conn PJ, Niswender CM. The metabotropic glutamate receptor 8 agonist (S)-3,4-DCPG reverses motor deficits in prolonged but not acute models of Parkinson's disease. Neuropharmacology 2012; 66:187-95. [PMID: 22546615 DOI: 10.1016/j.neuropharm.2012.03.029] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2012] [Revised: 03/27/2012] [Accepted: 03/29/2012] [Indexed: 10/28/2022]
Abstract
Metabotropic glutamate receptors (mGlus) are 7 Transmembrane Spanning Receptors (7TMs) that are differentially expressed throughout the brain and modulate synaptic transmission at both excitatory and inhibitory synapses. Recently, mGlus have been implicated as therapeutic targets for many disorders of the central nervous system, including Parkinson's disease (PD). Previous studies have shown that nonselective agonists of group III mGlus have antiparkinsonian effects in several animal models of PD, suggesting that these receptors represent promising targets for treating the motor symptoms of PD. However, the relative contributions of different group III mGlu subtypes to these effects have not been fully elucidated. Here we report that intracerebroventricular (icv) administration of the mGlu(8)-selective agonist (S)-3,4-dicarboxyphenylglycine (DCPG [ 2.5, 10, or 30 nmol]) does not alleviate motor deficits caused by acute (2 h) treatment with haloperidol or reserpine. However, following prolonged pretreatment with haloperidol (three doses evenly spaced over 18-20 h) or reserpine (18-20 h), DCPG robustly reverses haloperidol-induced catalepsy and reserpine-induced akinesia. Furthermore, DCPG (10 nmol, icv) reverses the long-lasting catalepsy induced by 20 h pretreatment with the decanoate salt of haloperidol. Finally, icv administration of DCPG ameliorates forelimb use asymmetry caused by unilateral 6-hydroxydopamine lesion of substantia nigra dopamine neurons. These findings suggest that mGlu(8) may partially mediate the antiparkinsonian effects of group III mGlu agonists in animal models of PD in which dopamine depletion or blockade of D(2)-like dopamine receptors is prolonged and indicate that selective activation of mGlu(8) may represent a novel therapeutic strategy for alleviating the motor symptoms of PD. This article is part of a Special Issue entitled 'Metabotropic Glutamate Receptors'.
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Affiliation(s)
- Kari A Johnson
- Department of Pharmacology, Vanderbilt University Medical Center, Nashville, TN, USA
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Blockx I, Van Camp N, Verhoye M, Boisgard R, Dubois A, Jego B, Jonckers E, Raber K, Siquier K, Kuhnast B, Dollé F, Nguyen HP, Von Hörsten S, Tavitian B, Van der Linden A. Genotype specific age related changes in a transgenic rat model of Huntington's disease. Neuroimage 2011; 58:1006-16. [PMID: 21767653 DOI: 10.1016/j.neuroimage.2011.07.007] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2011] [Revised: 06/29/2011] [Accepted: 07/04/2011] [Indexed: 12/15/2022] Open
Abstract
We aimed to characterize the transgenic Huntington rat model with in vivo imaging and identify sensitive and reliable biomarkers associated with early and progressive disease status. In order to do so, we performed a multimodality (DTI and PET) longitudinal imaging study, during which the same TgHD and wildtype (Wt) rats were repetitively scanned. Surprisingly, the relative ventricle volume was smaller but increased faster in TgHD compared to Wt animals. DTI (mean, axial, radial diffusivity) revealed subtle genotype-specific aging effects in the striatum and its surrounding white matter, already in the presymptomatic stage. Using ¹⁸F-FDG and ¹⁸F-Fallypride PET imaging, we were not able to demonstrate genotype-specific aging effects within the striatum. The outcome of this longitudinal study was somewhat surprising as it demonstrated a significant differential aging pattern in TgHD versus Wt animals. Although it seems that the TgHD rat model does not have a sufficient expression of disease yet at the age of 12 months, further validation of this model is highly beneficial since there is still an incomplete understanding of the early disease mechanisms of Huntington's disease.
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Affiliation(s)
- Ines Blockx
- Bio-Imaging Lab, University of Antwerp, Belgium
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Tantawy MN, Peterson TE, Jones CK, Johnson K, Rook JM, Conn PJ, Baldwin RM, Ansari MS, Kessler RM. Impact of isoflurane anesthesia on D2 receptor occupancy by [18F]fallypride measured by microPET with a modified Logan plot. Synapse 2011; 65:1173-80. [PMID: 21584868 DOI: 10.1002/syn.20955] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2011] [Accepted: 05/11/2011] [Indexed: 11/11/2022]
Abstract
UNLABELLED In the previous work, we reported a method that utilized imaging data collected from 60 to 120 min following [(18) F]fallypride administration to estimate the distribution volume ratio DVR' (DVR' ∝ DVR; DVR = 1 + BP(ND) , where BP(ND) is a measure of receptor density, DA D2 in this case). In this work, we use this method to assess the effects of isoflurane anesthesia on [(18) F]fallypride DVR'. METHODS Rats were injected with [(18) F]fallypride either unconsciously under ∼1.5% isoflurane via the tail vein (Group 1) or consciously via a catheter inserted either in the jugular vein (Group 2) or the tail vein (Group 3). After about 1 h of free access to food and water the rats were anesthetized with 1.5% isoflurane and imaged in a microPET for 60 min. The rats that were injected consciously (Groups 2 and 3) were placed in a rat restrainer during [(18) F]fallypride injection. They were habituated in that restrainer for 3 days prior to the experiment day to minimize restraint-related stress. For comparison, a control group of rats was imaged for 120 min simultaneously with the administration of [(18) F]fallypride i.v. while under 1.5% isoflurane. The DVR' estimates from the 60 min acquisitions were compared with the DVR' from the last 60 min of the 120 min acquisitions (after neglecting the first 60 min). In addition, the striatal time-activity curves were fit with a 2-tissue + plasma compartment model using an arbitrary simulated plasma input function to obtain k(3) /k(4) (≈ BP(ND) ) for the 60 and 120 min acquisitions. RESULTS Isoflurane anesthesia caused a significant reduction, up to 22%, in the DVR' estimates, which were 15.7 ± 0.3 (mean ± SE) for the controls, 17.7 ± 0.3 for Group 1, 19.2 ± 0.4 for Group 2, and 18.8 ± 0.7 for Group 3. The compartmental model fit produced similar results, ∼30% reduction in k(3) /k(4) for the 120-min acquisitions compared with the 60-min acquisitions (initial conscious uptake of the radiotracer). CONCLUSION The results of this study demonstrate that isoflurane anesthesia significantly decreases striatal [(18) F]fallypride BP(ND) in rats. Of similar importance, this work demonstrates the effectiveness of delayed scans following radiotracer injection and the implication that different types of studies can be conducted simultaneously with this method, including studies of behavioral and environmental impact on brain receptors.
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Affiliation(s)
- Mohammed N Tantawy
- Department of Radiology and Radiological Sciences, Vanderbilt University Medical Center, Nashville, Tennessee 37232, USA.
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Constantinescu CC, Coleman RA, Pan ML, Mukherjee J. Striatal and extrastriatal microPET imaging of D2/D3 dopamine receptors in rat brain with [¹⁸F]fallypride and [¹⁸F]desmethoxyfallypride. Synapse 2011; 65:778-87. [PMID: 21218455 DOI: 10.1002/syn.20904] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2010] [Accepted: 12/23/2010] [Indexed: 11/07/2022]
Abstract
In this study, we compared two different D(2/3) receptor ligands, [¹⁸F]fallypride and [¹⁸F]desmethoxyfallypride ([¹⁸F]DMFP) with respect to the duration of the scan, visualization of extrastriatal receptors, and binding potentials (BP(ND) ) in the rat brain. In addition, we studied the feasibility of using these tracers following a period of awake tracer uptake, during which the animal may perform a behavioral task. Male Sprague-Dawley rats were imaged with [¹⁸F]fallypride and with [¹⁸F]DMFP in four different studies using microPET. All scans were performed under isoflurane anesthesia. The first (test) and second (retest) study were 150-min baseline scans. No retest scans were performed with [¹⁸F]DMFP. A third study was a 60-min awake uptake of radiotracer followed by a 90-min scan. A fourth study was a 150-min competition scan with haloperidol (0.2 mg/kg) administered via tail vein at 90-min post-[¹⁸F]fallypride injection and 60-min post-[¹⁸F]DMFP. For the test-retest studies, BP(ND) was measured using both Logan noninvasive (LNI) method and the interval ratios (ITR) method. Cerebellum was used as a reference region. For the third study, the binding was measured only with the ITR method, and the results were compared to the baseline results. Studies showed that the average transient equilibrium time in the dorsal striatum (DSTR) was at 90 min for [¹⁸F]fallypride and 30 min for [¹⁸F]DMFP. The average BP(ND) for [¹⁸F]fallypride was 14.4 in DSTR, 6.8 in ventral striatum (VSTR), 1.3 in substantia nigra/ventral tegmental area (SN/VTA), 1.4 in colliculi (COL), and 1.5 in central gray area. In the case of [¹⁸F]DMFP, the average BP(ND) values were 2.2 in DSTR, 2.7 in VSTR, and 0.8 in SN/VTA. The haloperidol blockade showed detectable decrease in binding of both tracers in striatal regions with a faster displacement of [¹⁸F]DMFP. No significant changes in BP(ND) of [¹⁸F]fallypride due to the initial awake state of the animal were found, whereas BP(ND) of [¹⁸F]DMFP was significantly higher in the awake state compared to baseline. We were able to demonstrate that dynamic PET using MicroPET Inveon allows quantification of both striatal and extrastriatal [¹⁸F]fallypride binding in rats in vivo. Quantification of the striatal regions could be achieved with [¹⁸F]DMFP.
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Affiliation(s)
- Cristian C Constantinescu
- Preclinical Imaging, Department of Psychiatry and Human Behavior, University of California Irvine, Irvine, California 92697, USA.
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Rominger A, Mille E, Zhang S, Böning G, Förster S, Nowak S, Gildehaus FJ, Wängler B, Bartenstein P, Cumming P. Validation of the Octamouse for Simultaneous 18F-Fallypride Small-Animal PET Recordings from 8 Mice. J Nucl Med 2010; 51:1576-83. [DOI: 10.2967/jnumed.110.078451] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
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