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Darcey VL, Guo J, Chi M, Chung ST, Courville AB, Gallagher I, Herscovitch P, Howard R, LaNoire M, Milley L, Schick A, Stagliano M, Turner S, Urbanski N, Yang S, Yim E, Zhai N, Zhou MS, Hall KD. Striatal dopamine tone is positively associated with body mass index in humans as determined by PET using dual dopamine type-2 receptor antagonist tracers. MEDRXIV : THE PREPRINT SERVER FOR HEALTH SCIENCES 2023:2023.09.27.23296169. [PMID: 37886556 PMCID: PMC10602123 DOI: 10.1101/2023.09.27.23296169] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/28/2023]
Abstract
The relationship between adiposity and dopamine type-2 receptor binding potential (D2BP) in the human brain has been repeatedly studied for >20 years with highly discrepant results, likely due to variable methodologies and differing study populations. We conducted a controlled inpatient feeding study to measure D2BP in the striatum using positron emission tomography with both [18F]fallypride and [11C]raclopride in pseudo-random order in 54 young adults with a wide range of body mass index (BMI 20-44 kg/m2). Within-subject D2BP measurements using the two tracers were moderately correlated (r=0.47, p<0.001). D2BP was negatively correlated with BMI as measured by [11C]raclopride (r= -0.51; p<0.0001) but not [18F]fallypride (r=-0.01; p=0.92) and these correlation coefficients were significantly different from each other (p<0.001). Given that [18F]fallypride has greater binding affinity to dopamine type-2 receptors than [11C]raclopride, which is more easily displaced by endogenous dopamine, our results suggest that adiposity is positively associated with increased striatal dopamine tone.
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Affiliation(s)
- Valerie L Darcey
- Integrative Physiology Section, National Institute of Diabetes & Digestive & Kidney Diseases, National Institutes of Health, Bethesda, MD, USA
- Center on Compulsive Behaviors, Intramural Research Program, NIH, Bethesda, MD, USA
| | - Juen Guo
- Integrative Physiology Section, National Institute of Diabetes & Digestive & Kidney Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Meible Chi
- Integrative Physiology Section, National Institute of Diabetes & Digestive & Kidney Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Stephanie T Chung
- Diabetes, Endocrinology, and Obesity Branch, National Institute of Diabetes, Digestive, and Kidney Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Amber B Courville
- Human Energy and Body Weight Regulation Core, National Institute of Diabetes & Digestive & Kidney Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Isabelle Gallagher
- Integrative Physiology Section, National Institute of Diabetes & Digestive & Kidney Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Peter Herscovitch
- Positron Emission Tomography Department, Clinical Center, National Institutes of Health, Bethesda, MD, USA
| | - Rebecca Howard
- Integrative Physiology Section, National Institute of Diabetes & Digestive & Kidney Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Melissa LaNoire
- Integrative Physiology Section, National Institute of Diabetes & Digestive & Kidney Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Lauren Milley
- Integrative Physiology Section, National Institute of Diabetes & Digestive & Kidney Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Alex Schick
- Integrative Physiology Section, National Institute of Diabetes & Digestive & Kidney Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Michael Stagliano
- Integrative Physiology Section, National Institute of Diabetes & Digestive & Kidney Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Sara Turner
- Nutrition Department, Clinical Center, National Institutes of Health, Bethesda, MD, USA
| | - Nicholas Urbanski
- Integrative Physiology Section, National Institute of Diabetes & Digestive & Kidney Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Shanna Yang
- Nutrition Department, Clinical Center, National Institutes of Health, Bethesda, MD, USA
| | - Eunha Yim
- University of Maryland, College Park, MD, USA
| | - Nan Zhai
- Integrative Physiology Section, National Institute of Diabetes & Digestive & Kidney Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Megan S Zhou
- Integrative Physiology Section, National Institute of Diabetes & Digestive & Kidney Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Kevin D Hall
- Integrative Physiology Section, National Institute of Diabetes & Digestive & Kidney Diseases, National Institutes of Health, Bethesda, MD, USA
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2
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Lawn T, Howard MA, Turkheimer F, Misic B, Deco G, Martins D, Dipasquale O. From Neurotransmitters to Networks: Transcending Organisational Hierarchies with Molecular-informed Functional Imaging. Neurosci Biobehav Rev 2023; 150:105193. [PMID: 37086932 PMCID: PMC10390343 DOI: 10.1016/j.neubiorev.2023.105193] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2022] [Revised: 04/01/2023] [Accepted: 04/19/2023] [Indexed: 04/24/2023]
Abstract
The human brain exhibits complex interactions across micro, meso-, and macro-scale organisational principles. Recent synergistic multi-modal approaches have begun to link micro-scale information to systems level dynamics, transcending organisational hierarchies and offering novel perspectives into the brain's function and dysfunction. Specifically, the distribution of micro-scale properties (such as receptor density or gene expression) can be mapped onto macro-scale measures from functional MRI to provide novel neurobiological insights. Methodological approaches to enrich functional imaging analyses with molecular information are rapidly evolving, with several streams of research having developed relatively independently, each offering unique potential to explore the trans-hierarchical functioning of the brain. Here, we address the three principal streams of research - spatial correlation, molecular-enriched network, and in-silico whole brain modelling analyses - to provide a critical overview of the different sources of molecular information, how this information can be utilised within analyses of fMRI data, the merits and pitfalls of each methodology, and, through the use of key examples, highlight their promise to shed new light on key domains of neuroscientific inquiry.
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Affiliation(s)
- Timothy Lawn
- Department of Neuroimaging, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK.
| | - Matthew A Howard
- Department of Neuroimaging, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK.
| | - Federico Turkheimer
- Department of Neuroimaging, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK.
| | - Bratislav Misic
- Montreal Neurological Institute and Hospital, McGill University, Montreal, Québec, Canada.
| | - Gustavo Deco
- Center for Brain and Cognition, Computational Neuroscience Group, Department of Information and Communication Technologies, Universitat Pompeu Fabra, Ramon Trias Fargas 25-27, Barcelona 08005, Spain; Department of Neuropsychology, Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany; Institució Catalana de Recerca i Estudis Avançats (ICREA), Barcelona, Spain; Turner Institute for Brain and Mental Health, Monash University, Melbourne, VIC, Australia.
| | - Daniel Martins
- Department of Neuroimaging, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK.
| | - Ottavia Dipasquale
- Department of Neuroimaging, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK.
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3
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Microliter-scale reaction arrays for economical high-throughput experimentation in radiochemistry. Sci Rep 2022; 12:10263. [PMID: 35715457 PMCID: PMC9205965 DOI: 10.1038/s41598-022-14022-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2021] [Accepted: 05/31/2022] [Indexed: 01/14/2023] Open
Abstract
The increasing number of positron-emission tomography (PET) tracers being developed to aid drug development and create new diagnostics has led to an increased need for radiosynthesis development and optimization. Current radiosynthesis instruments are designed to produce large-scale clinical batches and are often limited to performing a single synthesis before they must be decontaminated by waiting for radionuclide decay, followed by thorough cleaning or disposal of synthesizer components. Though with some radiosynthesizers it is possible to perform a few sequential radiosyntheses in a day, none allow for parallel radiosyntheses. Throughput of one or a few experiments per day is not well suited for rapid optimization experiments. To combat these limitations, we leverage the advantages of droplet-radiochemistry to create a new platform for high-throughput experimentation in radiochemistry. This system contains an array of 4 heaters, each used to heat a set of 16 reactions on a small chip, enabling 64 parallel reactions for the rapid optimization of conditions in any stage of a multi-step radiosynthesis process. As examples, we study the syntheses of several 18F-labeled radiopharmaceuticals ([18F]Flumazenil, [18F]PBR06, [18F]Fallypride, and [18F]FEPPA), performing > 800 experiments to explore the influence of parameters including base type, base amount, precursor amount, solvent, reaction temperature, and reaction time. The experiments were carried out within only 15 experiment days, and the small volume (~ 10 μL compared to the ~ 1 mL scale of conventional instruments) consumed ~ 100 × less precursor per datapoint. This new method paves the way for more comprehensive optimization studies in radiochemistry and substantially shortening PET tracer development timelines.
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4
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Moldovean SN, Timaru DG, Chiş V. All-Atom Molecular Dynamics Investigations on the Interactions between D2 Subunit Dopamine Receptors and Three 11C-Labeled Radiopharmaceutical Ligands. Int J Mol Sci 2022; 23:ijms23042005. [PMID: 35216115 PMCID: PMC8880249 DOI: 10.3390/ijms23042005] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2022] [Revised: 02/04/2022] [Accepted: 02/08/2022] [Indexed: 11/24/2022] Open
Abstract
The D2 subunit dopamine receptor represents a key factor in modulating dopamine release. Moreover, the investigated radiopharmaceutical ligands used in positron emission tomography imaging techniques are known to bind D2 receptors, allowing for dopaminergic pathways quantification in the living human brain. Thus, the biophysical characterization of these radioligands is expected to provide additional insights into the interaction mechanisms between the vehicle molecules and their targets. Using molecular dynamics simulations and QM calculations, the present study aimed to investigate the potential positions in which the D2 dopamine receptor would most likely interact with the three distinctive synthetic 11C-labeled compounds (raclopride (3,5-dichloro-N-[[(2S)-1-ethylpyrrolidin-2-yl]methyl]-2-hydroxy-6-methoxybenzamide)—RACL, FLB457 (5-bromo-N-[[(2S)-1-ethylpyrrolidin-2-yl]methyl]-2,3-dimethoxybenzamide)—FLB457 and SCH23390 (R(+)-7-Chloro-8-hydroxy-3-methyl-1-phenyl-2,3,4,5-tetrahydro-1H-3-benzazepine)—SCH)), as well as to estimate the binding affinities of the ligand-receptor complexes. A docking study was performed prior to multiple 50 ns molecular dynamics productions for the ligands situated at the top and bottom interacting pockets of the receptor. The most prominent motions for the RACL ligand were described by the high fluctuations of the peripheral aliphatic -CH3 groups and by its C-Cl aromatic ring groups. In good agreement with the experimental data, the D2 dopamine receptor-RACL complex showed the highest interacting patterns for ligands docked at the receptor’s top position.
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Affiliation(s)
- Sanda Nastasia Moldovean
- Faculty of Physics, Babeş-Bolyai University, 400084 Cluj-Napoca, Romania; (S.N.M.); (D.-G.T.)
- Biomolecular Modeling and Computational Spectroscopy Laboratory, Institute for Research, Development and Innovation in Applied Natural Sciences, Babeş-Bolyai University, 400327 Cluj-Napoca, Romania
| | - Diana-Gabriela Timaru
- Faculty of Physics, Babeş-Bolyai University, 400084 Cluj-Napoca, Romania; (S.N.M.); (D.-G.T.)
| | - Vasile Chiş
- Faculty of Physics, Babeş-Bolyai University, 400084 Cluj-Napoca, Romania; (S.N.M.); (D.-G.T.)
- Biomolecular Modeling and Computational Spectroscopy Laboratory, Institute for Research, Development and Innovation in Applied Natural Sciences, Babeş-Bolyai University, 400327 Cluj-Napoca, Romania
- Correspondence:
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5
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Schifani C, Hafizi S, Tseng HH, Gerritsen C, Kenk M, Wilson AA, Houle S, Rusjan PM, Mizrahi R. Preliminary data indicating a connection between stress-induced prefrontal dopamine release and hippocampal TSPO expression in the psychosis spectrum. Schizophr Res 2019; 213:80-86. [PMID: 30409695 PMCID: PMC6500775 DOI: 10.1016/j.schres.2018.10.008] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/06/2018] [Revised: 10/12/2018] [Accepted: 10/16/2018] [Indexed: 12/31/2022]
Abstract
Prolonged stress can cause neuronal loss in the hippocampus resulting in disinhibition of glutamatergic neurons proposed to enhance dopaminergic firing in subcortical regions including striatal areas. Supporting this, imaging studies show increased striatal dopamine release in response to psychosocial stress in healthy individuals with low childhood maternal care, individuals at clinical high risk for psychosis (CHR) and patients with schizophrenia. The prefrontal cortex (PFC) is connected to the hippocampus and a key region to control neurochemical responses to stressful stimuli. We recently reported a disrupted PFC dopamine-stress regulation in schizophrenia, which was intact in CHR. Given the available evidence on the link between psychosocial stress, PFC dopamine release and hippocampal immune activation in psychosis, we explored, for the first time in vivo, whether stress-induced PFC dopamine release is associated with hippocampal TSPO expression (a neuroimmune marker) in the psychosis spectrum. We used an overlapping sample of antipsychotic-naïve subjects with CHR (n = 6) and antipsychotic-free schizophrenia patients (n = 9) from our previously published studies, measuring PFC dopamine release induced by a psychosocial stress task with [11C]FLB457 positron emission tomography (PET) and TSPO expression with [18F]FEPPA PET. We observed that participants on the psychosis spectrum with lower stress-induced dopamine release in PFC had significantly higher TSPO expression in hippocampus (β = -2.39, SE = 0.96, F(1,11) = 6.17, p = 0.030). Additionally, we report a positive association between stress-induced PFC dopamine release, controlled for hippocampal TSPO expression, and Global Assessment of Functioning. This is the first exploration of the relationship between PFC dopamine release and hippocampal TSPO expression in vivo in humans.
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Affiliation(s)
- Christin Schifani
- Research Imaging Centre, Centre for Addiction and Mental
Health, Toronto, Ontario, Canada
| | - Sina Hafizi
- Research Imaging Centre, Centre for Addiction and Mental
Health, Toronto, Ontario, Canada
| | - Huai-Hsuan Tseng
- Research Imaging Centre, Centre for Addiction and Mental
Health, Toronto, Ontario, Canada
| | - Cory Gerritsen
- Research Imaging Centre, Centre for Addiction and Mental
Health, Toronto, Ontario, Canada
| | - Miran Kenk
- Research Imaging Centre, Centre for Addiction and Mental
Health, Toronto, Ontario, Canada
| | - Alan A. Wilson
- Research Imaging Centre, Centre for Addiction and Mental
Health, Toronto, Ontario, Canada
| | - Sylvain Houle
- Research Imaging Centre, Centre for Addiction and Mental
Health, Toronto, Ontario, Canada
| | - Pablo M. Rusjan
- Research Imaging Centre, Centre for Addiction and Mental
Health, Toronto, Ontario, Canada,institute of Medical Science, University of Toronto,
Toronto, Ontario, Canada
| | - Romina Mizrahi
- Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, Ontario, Canada; Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Toronto, Ontario, Canada; Department of Psychiatry, University of Toronto, Toronto, Ontario, Canada; Institute of Medical Science, University of Toronto, Toronto, Ontario, Canada.
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6
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Juarez EJ, Castrellon JJ, Green MA, Crawford JL, Seaman KL, Smith CT, Dang LC, Matuskey D, Morris ED, Cowan RL, Zald DH, Samanez-Larkin GR. Reproducibility of the correlative triad among aging, dopamine receptor availability, and cognition. Psychol Aging 2019; 34:921-932. [PMID: 31589058 DOI: 10.1037/pag0000403] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
The evidence that dopamine function mediates the association between aging and cognition is one of the most cited findings in the cognitive neuroscience of aging. However, few and relatively small studies have directly examined these associations. Here we examined correlations among adult age, dopamine D2-like receptor (D2R) availability, and cognition in two cross-sectional studies of healthy human adults. Participants completed a short cognitive test battery and, on a separate day, a PET scan with either the high-affinity D2R tracer [18F]Fallypride (Study 1) or [11C]FLB457 (Study 2). Digit span, a measure of short-term memory maintenance and working memory, was the only cognitive test for which dopamine D2R availability partially mediated the age effect on cognition. In Study 1, age was negatively correlated with digit span. Striatal D2R availability was positively correlated with digit span controlling for age. The age effect on digit span was smaller when controlling for striatal D2R availability. Although other cognitive measures used here have individually been associated with age and D2R availability in prior studies, we found no consistent evidence for significant associations between low D2R availability and low cognitive performance on these measures. These results at best only partially supported the correlative triad of age, dopamine D2R availability, and cognition. While a wealth of other research in human and nonhuman animals demonstrates that dopamine makes critical contributions to cognition, the present studies suggest caution in interpreting PET findings as evidence that dopamine D2R loss is a primary cause of broad age-related declines in fluid cognition. (PsycINFO Database Record (c) 2019 APA, all rights reserved).
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Affiliation(s)
| | | | | | | | | | | | - Linh C Dang
- Department of Psychology, Vanderbilt University
| | - David Matuskey
- Department of Radiology and Biomedical Imaging, Yale University
| | - Evan D Morris
- Department of Radiology and Biomedical Imaging, Yale University
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7
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Tagore A, Schifani C, Rao N, Tseng HH, Zakzanis KK, Rusjan PM, Houle S, Mizrahi R. Prefrontal cortical dopamine release in clinical high risk for psychosis during a cognitive task: a [ 11C]FLB457 positron emission tomography study. Eur Neuropsychopharmacol 2019; 29:1023-1032. [PMID: 31351843 DOI: 10.1016/j.euroneuro.2019.06.004] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/19/2018] [Revised: 05/01/2019] [Accepted: 06/10/2019] [Indexed: 01/20/2023]
Abstract
Research suggests decreased cortical dopamine is a neural correlate of cognitive deficits in schizophrenia. Evidence of impaired cognitive task-induced cortical dopamine release was demonstrated in patients with psychosis. However, whether cortical dopamine release in response to a cognitive task in clinical high risk for psychosis (CHR) is also impaired, is currently unknown. We aimed to test dopamine release in the dorsolateral prefrontal cortex (DLPFC) and the anterior cingulate cortex (ACC) in antipsychotic-free CHR participants and healthy controls (HC) performing the Wisconsin Card Sorting Task (WCST). Two [11C]FLB457 PET scans were conducted for 13 CHR and 15 HC while performing the WCST and the sensorimotor control task (SMCT), respectively. A magnetic resonance image was acquired for anatomical delineation. Percentage change in binding potential (ΔBPND) in ACC and DLPFC in WCST were compared with the SMCT between CHR and HC. Mixed model analysis revealed no statistically significant differences in the cognitive task induced ΔBPND in any ROIs. There were no main effect of group (F(1, 26) = 0.348; p = 0.560) or ROI (F(1, 26) = 1.080; p = 0.308) and no significant Group x ROI interaction (F(1, 26) = 0.049; p = 0.826). Our findings suggest no statistically significant difference between CHR and HC in cognitive task-induced cortical dopamine release. This is the first in vivo study to illustrate that the cortical hypodopaminergic state observed in schizophrenia may not be present in its putative high-risk state.
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Affiliation(s)
- Abanti Tagore
- Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, Ontario, Canada; Institute of Medical Science, University of Toronto, Toronto, Ontario, Canada
| | - Christin Schifani
- Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, Ontario, Canada
| | - Naren Rao
- Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, Ontario, Canada; Department of Psychiatry, National Institute of Mental Health and Neurosciences, Bengaluru, Karnataka, India
| | - Huai-Hsuan Tseng
- Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, Ontario, Canada; Department of Psychiatry, National Cheng Kung University Hospital, College of Medicine, Tainan, Taiwan; Institute of Behavioral Medicine, College of Medicine, National Cheng Kung University, Tainan, Taiwan
| | - Konstantine K Zakzanis
- Department of Psychology, University of Toronto Scarborough, 1265 Military Trail, Toronto, Ontario M1C 1A4, Canada
| | - Pablo M Rusjan
- Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, Ontario, Canada; Institute of Medical Science, University of Toronto, Toronto, Ontario, Canada; Department of Psychiatry, University of Toronto, Toronto, Ontario, Canada; Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Toronto, Ontario, Canada
| | - Sylvain Houle
- Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, Ontario, Canada; Department of Psychiatry, University of Toronto, Toronto, Ontario, Canada; Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Toronto, Ontario, Canada
| | - Romina Mizrahi
- Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, Ontario, Canada; Institute of Medical Science, University of Toronto, Toronto, Ontario, Canada; Department of Psychiatry, University of Toronto, Toronto, Ontario, Canada; Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Toronto, Ontario, Canada.
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8
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Rios A, Wang J, Chao PH, van Dam RM. A novel multi-reaction microdroplet platform for rapid radiochemistry optimization. RSC Adv 2019; 9:20370-20374. [PMID: 35514735 PMCID: PMC9065505 DOI: 10.1039/c9ra03639c] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2019] [Accepted: 06/17/2019] [Indexed: 12/20/2022] Open
Abstract
During the development of novel tracers for positron emission tomography (PET), the optimization of the synthesis is hindered by practical limitations on the number of experiments that can be performed per day. Here we present a microliter droplet chip that contains multiple sites (4 or 16) to perform reactions simultaneously under the same or different conditions to accelerate radiosynthesis optimization. Multi-reaction microdroplet chip enables rapid radiotracer optimization for positron emission tomography.![]()
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Affiliation(s)
- Alejandra Rios
- Crump Institute of Molecular Imaging, University of California Los Angeles (UCLA) Los Angeles CA USA .,Physics and Biology in Medicine Interdepartmental Graduate Program, UCLA USA
| | - Jia Wang
- Crump Institute of Molecular Imaging, University of California Los Angeles (UCLA) Los Angeles CA USA .,Department of Bioengineering, UCLA USA
| | - Philip H Chao
- Crump Institute of Molecular Imaging, University of California Los Angeles (UCLA) Los Angeles CA USA .,Department of Bioengineering, UCLA USA
| | - R Michael van Dam
- Crump Institute of Molecular Imaging, University of California Los Angeles (UCLA) Los Angeles CA USA .,Physics and Biology in Medicine Interdepartmental Graduate Program, UCLA USA.,Department of Bioengineering, UCLA USA.,Department of Molecular & Medical Pharmacology, David Geffen School of Medicine, UCLA USA
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9
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Smith CT, Crawford JL, Dang LC, Seaman KL, San Juan MD, Vijay A, Katz DT, Matuskey D, Cowan RL, Morris ED, Zald DH, Samanez-Larkin GR. Partial-volume correction increases estimated dopamine D2-like receptor binding potential and reduces adult age differences. J Cereb Blood Flow Metab 2019; 39:822-833. [PMID: 29090626 PMCID: PMC6498753 DOI: 10.1177/0271678x17737693] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
The relatively modest spatial resolution of positron emission tomography (PET) increases the likelihood of partial volume effects such that binding potential (BPND) may be underestimated. Given structural grey matter losses across adulthood, partial volume effects may be even more problematic in older age leading to overestimation of adult age differences. Here we examined the effects of partial volume correction (PVC) in two studies from different sites using different high-affinity D2-like radioligands (18 F-Fallypride, 11C-FLB457) and different PET camera resolutions (∼5 mm, 2.5 mm). Results across both data sets revealed that PVC increased estimated BPND and reduced, though did not eliminate, age effects on BPND. As expected, the effects of PVC were smaller in higher compared to lower resolution data. Analyses using uncorrected data that controlled for grey matter volume in each region of interest approximated PVC corrected data for some but not all regions. Overall, the findings suggest that PVC increases estimated BPND in general and reduces adult age differences especially when using lower resolution cameras. The findings suggest that the past 30 years of research on dopamine receptor availability, for which very few studies use PVC, may overestimate effects of aging on dopamine receptor availability.
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Affiliation(s)
| | - Jennifer L Crawford
- 2 Department of Psychology, Yale University, New Haven, CT, USA.,3 Center for Cognitive Neuroscience, Duke University, Durham, NC, USA
| | - Linh C Dang
- 1 Department of Psychology, Vanderbilt University, Nashville, TN, USA
| | - Kendra L Seaman
- 2 Department of Psychology, Yale University, New Haven, CT, USA.,3 Center for Cognitive Neuroscience, Duke University, Durham, NC, USA
| | - M Danica San Juan
- 1 Department of Psychology, Vanderbilt University, Nashville, TN, USA
| | - Aishwarya Vijay
- 4 Department of Radiology and Biomedical Imaging, Yale University, New Haven, CT, USA
| | - Daniel T Katz
- 1 Department of Psychology, Vanderbilt University, Nashville, TN, USA
| | - David Matuskey
- 4 Department of Radiology and Biomedical Imaging, Yale University, New Haven, CT, USA.,5 Department of Psychiatry, Yale University, New Haven, CT, USA
| | - Ronald L Cowan
- 1 Department of Psychology, Vanderbilt University, Nashville, TN, USA.,6 Department of Psychiatry and Behavioral Sciences, Vanderbilt University School of Medicine, Nashville, TN, USA.,7 Department of Radiology and Radiological Sciences, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Evan D Morris
- 4 Department of Radiology and Biomedical Imaging, Yale University, New Haven, CT, USA.,5 Department of Psychiatry, Yale University, New Haven, CT, USA.,8 Department of Biomedical Engineering, Yale University, New Haven, CT USA
| | - David H Zald
- 1 Department of Psychology, Vanderbilt University, Nashville, TN, USA.,6 Department of Psychiatry and Behavioral Sciences, Vanderbilt University School of Medicine, Nashville, TN, USA
| | - Gregory R Samanez-Larkin
- 2 Department of Psychology, Yale University, New Haven, CT, USA.,3 Center for Cognitive Neuroscience, Duke University, Durham, NC, USA.,9 Department of Psychology and Neuroscience, Duke University, Durham, NC, USA
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10
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Rao N, Northoff G, Tagore A, Rusjan P, Kenk M, Wilson A, Houle S, Strafella A, Remington G, Mizrahi R. Impaired Prefrontal Cortical Dopamine Release in Schizophrenia During a Cognitive Task: A [11C]FLB 457 Positron Emission Tomography Study. Schizophr Bull 2019; 45:670-679. [PMID: 29878197 PMCID: PMC6483585 DOI: 10.1093/schbul/sby076] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Evidence from several lines of research suggests decreased dopamine release in the prefrontal cortex as the neurochemical correlates of cognitive deficits in schizophrenia (SCZ). However, in vivo examination of cortical hypodopaminergia using positron emission tomography (PET) during cognitive task performance in SCZ remains to be investigated. We examined dopamine release in anterior cingulate cortex (ACC) and dorsolateral prefrontal cortex (DLPFC), using PET while participants were performing a cognitive task. Thirteen drug-free patients with SCZ and 13 healthy volunteers (HV) matched for age and sex participated in the study. Data were acquired between 2011 and 2015. Two PET scans with [11C]FLB 457 were acquired while the participants were performing the Wisconsin Card Sorting Test (WCST) and a sensorimotor control task (SMCT). A magnetic resonance image was acquired for anatomical delineation. Differences in cortical dopamine release between SCZ and HV, indexed as percentage change in binding potential between WCST and SMCT (ΔBPND), were calculated in ACC and DLPFC. We observed significant differences in the ΔBPND in ACC (HV = 4.40 ± 6.00; SCZ = -11.48 ± 15.08; t = 3.52; P = .003) and a trend-level difference in ΔBPND in DLPFC (HV = -0.58 ± 8.45; SCZ = -7.79 ± 11.28; t = 1.84; P = .079), suggesting dopamine depletion in cortical brain regions in patients with SCZ while performing a cognitive task. These results provide the first in vivo evidence for reduced dopamine release or even dopamine depletion while performing cognitive task in ACC and DLPFC in patients with SCZ. The present results provide support for the frontal hypodopaminergia hypothesis of cognitive symptoms in SCZ.
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Affiliation(s)
- Naren Rao
- Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, ON, Canada,Department of Psychiatry, National Institute of Mental Health and Neurosciences, Bengaluru, Karnataka, India
| | - Georg Northoff
- Institute of Mental Health Research: Mind, Brain Imaging and Neuroethics, University of Ottawa, Ottawa, ON, Canada
| | - Abanti Tagore
- Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, ON, Canada
| | - Pablo Rusjan
- Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, ON, Canada
| | - Miran Kenk
- Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, ON, Canada
| | - Alan Wilson
- Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, ON, Canada
| | - Sylvain Houle
- Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, ON, Canada
| | - Antonio Strafella
- Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, ON, Canada
| | - Gary Remington
- Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, ON, Canada
| | - Romina Mizrahi
- Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, ON, Canada,To whom correspondence should be addressed; University of Toronto, Focus on Youth Psychosis Prevention (FYPP), Centre for Addiction and Mental Health, 250 College Street, Toronto, ON M5T 1R8 Canada; tel: 416-535-8501 ext. 34508, fax: 416-979-4656, e-mail:
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11
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Xu Y, Li Z. Imaging metabotropic glutamate receptor system: Application of positron emission tomography technology in drug development. Med Res Rev 2019; 39:1892-1922. [DOI: 10.1002/med.21566] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2018] [Revised: 01/18/2019] [Accepted: 01/24/2019] [Indexed: 12/17/2022]
Affiliation(s)
- Youwen Xu
- Independent Consultant and Contractor, Radiopharmaceutical Development, Validation and Bio-Application; Philadelphia Pennsylvania
| | - Zizhong Li
- Pharmaceutical Research and Development, SOFIE Biosciences; Somerset New Jersey
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12
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Stewart MN, Shao X, Desmond TJ, Forrest TJ, Arteaga J, Stauff J, Scott PJH. Synthesis and pre-clinical evaluation of a potential radiotracer for PET imaging of the dopamine D 3 receptor. MEDCHEMCOMM 2018; 9:1315-1322. [PMID: 30151086 PMCID: PMC6097203 DOI: 10.1039/c8md00094h] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/18/2018] [Accepted: 06/28/2018] [Indexed: 01/11/2023]
Abstract
There is considerable interest in using positron emission tomography (PET) imaging to understand the function of dopamine D3 receptors. Due to high sequence homology with D2 receptors, development of D3-selective PET radiotracers has been challenging. In an effort to overcome this issue, we report the radiosynthesis of a new selective D3 ligand with carbon-11 ([11C]1 ), and its initial preclincial evaluation as a potential PET radiotracer for in vivo imaging of D3 receptors. [11C]1 was prepared via [11C]CO2 fixation in 0.1% non-corrected radiochemical yield, good radiochemical purity (>95%) and high specific activity (>2000 Ci mmol-1). [11C]1 exhibited specific binding to D3 receptors using ex vivo autoradiography experiments with rat brain, but only 14-fold selectivity over D2 receptors which is lower than the 1400-fold value reported previously for cell studies. Rodent PET imaging revealed reasonable uptake of the radiotracer in areas of the brain known to be rich in D3 receptors.
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Affiliation(s)
- Megan N Stewart
- Department of Radiology , University of Michigan Medical School , Ann Arbor , MI 48109 , USA .
- Department of Medicinal Chemistry , University of Michigan , Ann Arbor , MI 48105 , USA
| | - Xia Shao
- Department of Radiology , University of Michigan Medical School , Ann Arbor , MI 48109 , USA .
| | - Timothy J Desmond
- Department of Radiology , University of Michigan Medical School , Ann Arbor , MI 48109 , USA .
| | - Taylor J Forrest
- Department of Radiology , University of Michigan Medical School , Ann Arbor , MI 48109 , USA .
| | - Janna Arteaga
- Department of Radiology , University of Michigan Medical School , Ann Arbor , MI 48109 , USA .
| | - Jenelle Stauff
- Department of Radiology , University of Michigan Medical School , Ann Arbor , MI 48109 , USA .
| | - Peter J H Scott
- Department of Radiology , University of Michigan Medical School , Ann Arbor , MI 48109 , USA .
- Department of Medicinal Chemistry , University of Michigan , Ann Arbor , MI 48105 , USA
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13
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Schifani C, Tseng HH, Kenk M, Tagore A, Kiang M, Wilson AA, Houle S, Rusjan PM, Mizrahi R. Cortical stress regulation is disrupted in schizophrenia but not in clinical high risk for psychosis. Brain 2018; 141:2213-2224. [PMID: 29860329 PMCID: PMC6022671 DOI: 10.1093/brain/awy133] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2017] [Revised: 03/15/2018] [Accepted: 04/02/2018] [Indexed: 12/11/2022] Open
Abstract
While alterations in striatal dopamine in psychosis and stress have been well studied, the role of dopamine in prefrontal cortex is poorly understood. To date, no study has investigated the prefrontocortical dopamine response to stress in the psychosis spectrum, even though the dorsolateral and medial prefrontal cortices are key regions in cognitive and emotional regulation, respectively. The present study uses the high-affinity dopamine D2/3 receptor radiotracer 11C-FLB457 and PET together with a validated psychosocial stress challenge to investigate the dorsolateral and medial prefrontocortical dopamine response to stress in schizophrenia and clinical high risk for psychosis. Forty participants completed two 11C-FLB457 PET scans (14 antipsychotic-free schizophrenia, 14 clinical high risk for psychosis and 12 matched healthy volunteers), one while performing a Sensory Motor Control Task (control) and another while performing the Montreal Imaging Stress Task (stress). Binding potential (BPND) was estimated using Simplified Reference Tissue Model with cerebellar cortex as reference region. Dopamine release was defined as per cent change in BPND between control and stress scans (ΔBPND) using a novel correction for injected mass. Salivary cortisol response (ΔAUCI) was assessed throughout the tasks and its relationship with dopamine release examined. 11C-FLB457 binding at control conditions was significantly different between groups in medial [F(2,37) = 7.98, P = 0.0013] and dorsolateral [F(2,37) = 6.97, P = 0.0027] prefrontal cortex with schizophrenia patients having lower BPND than participants at clinical high risk for psychosis and healthy volunteers, but there was no difference in ΔBPND among groups [dorsolateral prefrontal cortex: F(2,37) = 1.07, P = 0.35; medial prefrontal cortex: F(2,37) = 0.54, P = 0.59]. We report a positive relationship between ΔAUCI and 11C-FLB457 ΔBPND in dorsolateral and medial prefrontal cortex in healthy volunteers (r = 0.72, P = 0.026; r = 0.76, P = 0.014, respectively) and in participants at clinical high risk for psychosis (r = 0.76, P = 0.0075; r = 0.72, P = 0.018, respectively), which was absent in schizophrenia (r = 0.46, P = 1.00; r = 0.19, P = 1.00, respectively). Furthermore, exploratory associations between ΔBPND or ΔAUCI and stress or anxiety measures observed in clinical high risk for psychosis were absent in schizophrenia. These findings provide first direct evidence of a disrupted prefrontocortical dopamine-stress regulation in schizophrenia.
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Affiliation(s)
- Christin Schifani
- Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, Ontario, Canada
| | - Huai-Hsuan Tseng
- Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, Ontario, Canada
| | - Miran Kenk
- Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, Ontario, Canada
| | - Abanti Tagore
- Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, Ontario, Canada
- Institute of Medical Science, University of Toronto, Toronto, Ontario, Canada
| | - Michael Kiang
- Institute of Medical Science, University of Toronto, Toronto, Ontario, Canada
- Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Toronto, Ontario, Canada
- Department of Psychiatry, University of Toronto, Toronto, Ontario, Canada
| | - Alan A Wilson
- Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, Ontario, Canada
| | - Sylvain Houle
- Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, Ontario, Canada
| | - Pablo M Rusjan
- Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, Ontario, Canada
- Institute of Medical Science, University of Toronto, Toronto, Ontario, Canada
| | - Romina Mizrahi
- Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, Ontario, Canada
- Institute of Medical Science, University of Toronto, Toronto, Ontario, Canada
- Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Toronto, Ontario, Canada
- Department of Psychiatry, University of Toronto, Toronto, Ontario, Canada
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14
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Godfrey JR, Diaz MP, Pincus M, Kovacs-Balint Z, Feczko E, Earl E, Miranda-Dominguez O, Fair D, Sanchez MM, Wilson ME, Michopoulos V. Diet matters: Glucocorticoid-related neuroadaptations associated with calorie intake in female rhesus monkeys. Psychoneuroendocrinology 2018; 91:169-178. [PMID: 29567621 PMCID: PMC5899678 DOI: 10.1016/j.psyneuen.2018.03.008] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/27/2017] [Revised: 01/31/2018] [Accepted: 03/13/2018] [Indexed: 01/22/2023]
Abstract
Exposure to psychosocial stressors increases consumption of palatable, calorically dense diets (CDD) and the risk for obesity, especially in females. While consumption of an obesogenic diet and chronic stress have both been shown to decrease dopamine 2 receptor (D2R) binding and alter functional connectivity (FC) within the prefrontal cortex (PFC) and the nucleus accumbens (NAcc), it remains uncertain how social experience and dietary environment interact to affect reward pathways critical for the regulation of motivated behavior. Using positron emission tomography (PET) and resting state functional connectivity magnetic resonance neuroimaging (rs-fMRI), in female rhesus monkeys maintained in a low calorie chow (n = 18) or a dietary choice condition (chow and a CDD; n = 16) for 12 months, the current study tested the overarching hypothesis that the adverse social experience resulting from subordinate social status would interact with consumption of an obesogenic diet to increase caloric intake that would be predicted by greater cortisol, lower prefrontal D2R binding potential (D2R-BP) and lower PFC-NAcc FC. Results showed that the consequences of adverse social experience imposed by chronic social subordination vary significantly depending on the dietary environment and are associated with alterations in prefrontal D2R-BP and FC in NAcc-PFC sub-regions that predict differences in caloric intake, body weight gain, and fat accumulation. Higher levels of cortisol in the chow-only condition were associated with mild inappetence, as well as increased orbitofrontal (OFC) D2R-BP and greater FC between the NAcc and the dorsolateral PFC (dlPFC) and ventromedial PFC (vmPFC). However, increased cortisol release in females in the dietary choice condition was associated with reduced prefrontal D2R-BP, and opposite FC between the NAcc and the vmPFC and dlPFC observed in the chow-only females. Importantly, the degree of these glucocorticoid-related neuroadaptations predicted significantly more total calorie intake as well as more consumption of the CDD for females having a dietary choice, but had no relation to calorie intake in the chow-only condition. Overall, the current findings suggest that dietary environment modifies the consequences of adverse social experience on reward pathways and appetite regulation and, in an obesogenic dietary environment, may reflect impaired cognitive control of food intake.
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Affiliation(s)
| | | | - Melanie Pincus
- Yerkes National Primate Research Center, Atlanta, Georgia
| | | | - Eric Feczko
- Department Of Behavioral Neuroscience, Oregon Health & Science University, Portland, OR
| | - Eric Earl
- Department Of Behavioral Neuroscience, Oregon Health & Science University, Portland, OR
| | | | - Damien Fair
- Department Of Behavioral Neuroscience, Oregon Health & Science University, Portland, OR
| | - Mar M. Sanchez
- Yerkes National Primate Research Center, Atlanta, Georgia,Department of Psychiatry and Behavioral Sciences, Emory University School of Medicine, Atlanta, Georgia
| | - Mark E. Wilson
- Yerkes National Primate Research Center, Atlanta, Georgia,Department of Psychiatry and Behavioral Sciences, Emory University School of Medicine, Atlanta, Georgia
| | - Vasiliki Michopoulos
- Yerkes National Primate Research Center, Atlanta, GA, United States; Department of Psychiatry and Behavioral Sciences, Emory University School of Medicine, Atlanta, GA, United States.
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Thiruchselvam T, Malik S, Le Foll B. A review of positron emission tomography studies exploring the dopaminergic system in substance use with a focus on tobacco as a co-variate. THE AMERICAN JOURNAL OF DRUG AND ALCOHOL ABUSE 2016; 43:197-214. [PMID: 27901585 DOI: 10.1080/00952990.2016.1257633] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
With the evolving sensitivity of positron emission tomography (PET) and the emergence of novel radiotracers, greater insight has been gained into the dopaminergic system as it relates to substance use. In this review, we summarize PET investigations from the last ten years that explore the dopaminergic system in tobacco, alcohol, stimulant, opiates, and cannabis addiction. In light of the prevalence of substance co-use, this review will also explore the effect of tobacco and other substance abuse co-morbidity on the dopaminergic system across study samples in the reviewed literature. In non-dependence, increased DA transmission following acute stimulant administration is a robust and consistent observation but is less detectable following acute alcohol and tobacco, where it likely represents a conditioned effect mediating reward expectation. Chronic drug exposure is generally associated with a hypo-functioning pre-synaptic dopamine system and lower D2/D3 receptor availability relative to healthy controls. Emerging evidence also shows that stimulant use disorders in particular may also be associated with greater D3 receptor availability relative to controls. A defined role for the dopaminergic system in cannabis and opiate use is yet to be elucidated. Future work is also needed to delineate the potential interactive effects of acute and chronic tobacco and substance co-use on the dopaminergic system.
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Affiliation(s)
- Thulasi Thiruchselvam
- b Translational Addiction Research Laboratory, Campbell Family Mental Health Research Institute , Centre for Addiction and Mental Health , Toronto , ON , Canada
| | - Saima Malik
- b Translational Addiction Research Laboratory, Campbell Family Mental Health Research Institute , Centre for Addiction and Mental Health , Toronto , ON , Canada
| | - Bernard Le Foll
- a Addiction Medicine Service, Ambulatory Care and Structured Treatments , Centre for Addiction and Mental Health , Toronto , ON , Canada.,b Translational Addiction Research Laboratory, Campbell Family Mental Health Research Institute , Centre for Addiction and Mental Health , Toronto , ON , Canada.,c Department of Family and Community Medicine , Pharmacology and Toxicology, Psychiatry, Institute of Medical Sciences, University of Toronto , Toronto , ON , Canada.,d Campbell Family Mental Health Research Institute, Center for Addiction and Mental Health , Toronto , ON , Canada
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16
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Midbrain functional connectivity and ventral striatal dopamine D2-type receptors: link to impulsivity in methamphetamine users. Mol Psychiatry 2016; 21:1554-1560. [PMID: 26830141 PMCID: PMC4970974 DOI: 10.1038/mp.2015.223] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/04/2015] [Revised: 11/11/2015] [Accepted: 12/07/2015] [Indexed: 12/23/2022]
Abstract
Stimulant use disorders are associated with deficits in striatal dopamine receptor availability, abnormalities in mesocorticolimbic resting-state functional connectivity (RSFC) and impulsivity. In methamphetamine-dependent research participants, impulsivity is correlated negatively with striatal D2-type receptor availability, and mesocorticolimbic RSFC is stronger than that in controls. The extent to which these features of methamphetamine dependence are interrelated, however, is unknown. This question was addressed in two studies. In Study 1, 19 methamphetamine-dependent and 26 healthy control subjects underwent [18F]fallypride positron emission tomography to measure ventral striatal dopamine D2-type receptor availability, indexed by binding potential (BPND), and functional magnetic resonance imaging (fMRI) to assess mesocorticolimbic RSFC, using a midbrain seed. In Study 2, an independent sample of 20 methamphetamine-dependent and 18 control subjects completed the Barratt Impulsiveness Scale in addition to fMRI. Study 1 showed a significant group by ventral striatal BPND interaction effect on RSFC, reflecting a negative relationship between ventral striatal BPND and RSFC between the midbrain and striatum, orbitofrontal cortex and insula in methamphetamine-dependent participants, but a positive relationship in the control group. In Study 2, an interaction of the group with RSFC on impulsivity was observed. Methamphetamine-dependent users exhibited a positive relationship of midbrain RSFC to the left ventral striatum with cognitive impulsivity, whereas a negative relationship was observed in healthy controls. The results indicate that ventral striatal D2-type receptor signaling may affect the system-level activity within the mesocorticolimbic system, providing a functional link that may help explain high impulsivity in methamphetamine-dependent individuals.
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17
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Milella MS, Fotros A, Gravel P, Casey KF, Larcher K, Verhaeghe JA, Cox SM, Reader AJ, Dagher A, Benkelfat C, Leyton M. Cocaine cue-induced dopamine release in the human prefrontal cortex. J Psychiatry Neurosci 2016; 41:322-30. [PMID: 26900792 PMCID: PMC5008921 DOI: 10.1503/jpn.150207] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
BACKGROUND Accumulating evidence indicates that drug-related cues can induce dopamine (DA) release in the striatum of substance abusers. Whether these same cues provoke DA release in the human prefrontal cortex remains unknown. METHODS We used high-resolution positron emission tomography with [18F]fallypride to measure cortical and striatal DA D2/3 receptor availability in the presence versus absence of drug-related cues in volunteers with current cocaine dependence. RESULTS Twelve individuals participated in our study. Among participants reporting a craving response (9 of 12), exposure to the cocaine cues significantly decreased [18F]fallypride binding potential (BPND) values in the medial orbitofrontal cortex and striatum. In all 12 participants, individual differences in the magnitude of craving correlated with BPND changes in the medial orbitofrontal cortex, dorsolateral prefrontal cortex, anterior cingulate, and striatum. Consistent with the presence of autoreceptors on mesostriatal but not mesocortical DA cell bodies, midbrain BPND values were significantly correlated with changes in BPND within the striatum but not the cortex. The lower the midbrain D2 receptor levels, the greater the striatal change in BPND and self-reported craving. LIMITATIONS Limitations of this study include its modest sample size, with only 2 female participants. Newer tracers might have greater sensitivity to cortical DA release. CONCLUSION In people with cocaine use disorders, the presentation of drug-related cues induces DA release within cortical and striatal regions. Both effects are associated with craving, but only the latter is regulated by midbrain autoreceptors. Together, the results suggest that cortical and subcortical DA responses might both influence drug-focused incentive motivational states, but with separate regulatory mechanisms.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | | | - Marco Leyton
- Correspondence to: M. Leyton, Department of Psychiatry, McGill University, 1033 Pine Ave. West, Montreal QC, Canada, H3A 1A1;
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18
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England CG, Ehlerding EB, Cai W. Imaging the Biodistribution and Performance of Transplanted Stem Cells with PET. J Nucl Med 2016; 57:1331-2. [PMID: 27199354 DOI: 10.2967/jnumed.116.173963] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2016] [Accepted: 04/11/2016] [Indexed: 11/16/2022] Open
Affiliation(s)
| | - Emily B Ehlerding
- Department of Medical Physics, University of Wisconsin-Madison, Madison, Wisconsin
| | - Weibo Cai
- Department of Medical Physics, University of Wisconsin-Madison, Madison, Wisconsin Department of Radiology, University of Wisconsin-Madison, Madison, Wisconsin; and Carbone Cancer Center, University of Wisconsin, Madison, Wisconsin
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19
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Okita K, Ghahremani DG, Payer DE, Robertson CL, Dean AC, Mandelkern MA, London ED. Emotion dysregulation and amygdala dopamine D2-type receptor availability in methamphetamine users. Drug Alcohol Depend 2016; 161:163-70. [PMID: 26880595 PMCID: PMC4792713 DOI: 10.1016/j.drugalcdep.2016.01.029] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/11/2015] [Revised: 01/30/2016] [Accepted: 01/30/2016] [Indexed: 10/22/2022]
Abstract
BACKGROUND Individuals who use methamphetamine chronically exhibit emotional and dopaminergic neurochemical deficits. Although the amygdala has an important role in emotion processing and receives dopaminergic innervation, little is known about how dopamine transmission in this region contributes to emotion regulation. This investigation aimed to evaluate emotion regulation in subjects who met DSM-IV criteria for methamphetamine dependence, and to test for a relationship between self-reports of difficulty in emotion regulation and D2-type dopamine receptor availability in the amygdala. METHOD Ninety-four methamphetamine-using and 102 healthy-control subjects completed the Difficulties in Emotion Regulation Scale (DERS); 33 of those who used methamphetamine completed the Addiction Severity Index (ASI). A subset of 27 methamphetamine-group and 20 control-group subjects completed positron emission tomography with [(18)F]fallypride to assay amygdala D2-type dopamine receptor availability, measured as binding potential (BPND). RESULTS The methamphetamine group scored higher than the control group on the DERS total score (p<0.001), with DERS total score positively correlated with the Drug Composite Score on the ASI (p=0.02) in the methamphetamine group. The DERS total score was positively correlated with amygdala BPND in both groups and the combined group of participants (combined: r=0.331, p=0.02), and the groups did not differ in this relationship. CONCLUSION These findings highlight problems with emotion regulation linked to methamphetamine use, possibly contributing to personal and interpersonal behavioral problems. They also suggest that D2-type dopamine receptors in the amygdala contribute to emotion regulation in both healthy and methamphetamine-using subjects.
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Affiliation(s)
- Kyoji Okita
- Department of Psychiatry and Biobehavioral Sciences, University of California Los Angeles, Los Angeles, CA, USA 90024,Department of Research, VA Greater Los Angeles Healthcare System, Los Angeles, CA, USA 90073
| | - Dara G. Ghahremani
- Department of Psychiatry and Biobehavioral Sciences, University of California Los Angeles, Los Angeles, CA, USA 90024
| | - Doris E. Payer
- Addiction Imaging Research Group, Centre for Addiction and Mental Health, Toronto, Ontario M5T 1R8, Canada,Department of Psychiatry, University of Toronto, Toronto, Ontario M5T 1R8, Canada
| | - Chelsea L. Robertson
- Department of Molecular and Medical Pharmacology, University of California Los Angeles, Los Angeles, CA, USA 90024,Department of Research, VA Greater Los Angeles Healthcare System, Los Angeles, CA, USA 90073
| | - Andy C. Dean
- Department of Psychiatry and Biobehavioral Sciences, University of California Los Angeles, Los Angeles, CA, USA 90024
| | - Mark A. Mandelkern
- Department of Research, VA Greater Los Angeles Healthcare System, Los Angeles, CA, USA 90073,Department of Physics, University of California Irvine, Irvine, CA, USA 92697
| | - Edythe D. London
- Department of Psychiatry and Biobehavioral Sciences, University of California Los Angeles, Los Angeles, CA, USA 90024,Department of Molecular and Medical Pharmacology, University of California Los Angeles, Los Angeles, CA, USA 90024,Brain Research Institute, University of California Los Angeles, Los Angeles, CA, USA 90024,Department of Research, VA Greater Los Angeles Healthcare System, Los Angeles, CA, USA 90073
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20
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Eisenmenger LB, Huo EJ, Hoffman JM, Minoshima S, Matesan MC, Lewis DH, Lopresti BJ, Mathis CA, Okonkwo DO, Mountz JM. Advances in PET Imaging of Degenerative, Cerebrovascular, and Traumatic Causes of Dementia. Semin Nucl Med 2016; 46:57-87. [DOI: 10.1053/j.semnuclmed.2015.09.003] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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21
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Ballard ME, Dean AC, Mandelkern MA, London ED. Striatal Dopamine D2/D3 Receptor Availability Is Associated with Executive Function in Healthy Controls but Not Methamphetamine Users. PLoS One 2015; 10:e0143510. [PMID: 26657223 PMCID: PMC4699455 DOI: 10.1371/journal.pone.0143510] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2015] [Accepted: 11/05/2015] [Indexed: 11/18/2022] Open
Abstract
Background Dopamine D2/D3 receptor availability in the striatum has been linked with executive function in healthy individuals, and is below control levels among drug addicts, possibly contributing to diminished executive function in the latter group. This study tested for an association of striatal D2/D3 receptor availability with a measure of executive function among research participants who met DSM-IV criteria for methamphetamine dependence. Methods Methamphetamine users and non-user controls (n = 18 per group) completed the Wisconsin Card Sorting Test and positron emission tomography with [18F]fallypride. Results The methamphetamine users displayed significantly lower striatal D2/D3 receptor availability on average than controls after controlling for age and education (p = 0.008), but they did not register greater proportions of either perseverative or non-perseverative errors when controlling for education (both ps ≥ 0.622). The proportion of non-perseverative, but not perseverative, errors was negatively correlated with striatal D2/D3 receptor availability among controls (r = -0.588, p = 0.010), but not methamphetamine users (r = 0.281, p = 0.258), and the group-wise interaction was significant (p = 0.030). Conclusions These results suggest that cognitive flexibility, as measured by perseverative errors on the Wisconsin Card Sorting Test, is not determined by signaling through striatal D2/D3 receptors in healthy controls, and that in stimulant abusers, who have lower D2/D3 receptor availability, compensation can effectively maintain other executive functions, which are associated with D2/D3 receptor signaling in controls.
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Affiliation(s)
- Michael E. Ballard
- Department of Psychiatry and Biobehavioral Sciences, University of California Los Angeles, Los Angeles, California, United States of America
- VA Greater Los Angeles Healthcare System, Los Angeles, California, United States of America
| | - Andy C. Dean
- Department of Psychiatry and Biobehavioral Sciences, University of California Los Angeles, Los Angeles, California, United States of America
- Brain Research Institute, University of California Los Angeles, Los Angeles, California, United States of America
| | - Mark A. Mandelkern
- VA Greater Los Angeles Healthcare System, Los Angeles, California, United States of America
- Department of Physics, University of California Irvine, Irvine, California, United States of America
| | - Edythe D. London
- Department of Psychiatry and Biobehavioral Sciences, University of California Los Angeles, Los Angeles, California, United States of America
- VA Greater Los Angeles Healthcare System, Los Angeles, California, United States of America
- Brain Research Institute, University of California Los Angeles, Los Angeles, California, United States of America
- Department of Molecular and Medical Pharmacology, University of California Los Angeles, Los Angeles, California, United States of America
- * E-mail:
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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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Sergeev ME, Morgia F, Lazari M, Wang C, van Dam RM. Titania-catalyzed radiofluorination of tosylated precursors in highly aqueous medium. J Am Chem Soc 2015; 137:5686-94. [PMID: 25860121 DOI: 10.1021/jacs.5b02659] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Nucleophilic radiofluorination is an efficient synthetic route to many positron-emission tomography (PET) probes, but removal of water to activate the cyclotron-produced [(18)F]fluoride has to be performed prior to reaction, which significantly increases overall radiolabeling time and causes radioactivity loss. In this report, we demonstrate the possibility of (18)F-radiofluorination in highly aqueous medium. The method utilizes titania nanoparticles, 1:1 (v/v) acetonitrile-thexyl alcohol solvent mixture, and tetra-n-butylammonium bicarbonate as a phase-transfer agent. Efficient radiolabeling is directly performed with aqueous [(18)F]fluoride without the need for a drying/azeotroping step to significantly reduce radiosynthesis time. High radiochemical purity of the target compound is also achieved. The substrate scope of the synthetic strategy is demonstrated with a range of aromatic, aliphatic, and cycloaliphatic tosylated precursors.
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Affiliation(s)
- Maxim E Sergeev
- Department of Molecular and Medical Pharmacology and Crump Institute for Molecular Imaging, David Geffen School of Medicine at University of California, Los Angeles, 570 Westwood Plaza, Los Angeles, California 90095, United States
| | - Federica Morgia
- Department of Molecular and Medical Pharmacology and Crump Institute for Molecular Imaging, David Geffen School of Medicine at University of California, Los Angeles, 570 Westwood Plaza, Los Angeles, California 90095, United States
| | - Mark Lazari
- Department of Molecular and Medical Pharmacology and Crump Institute for Molecular Imaging, David Geffen School of Medicine at University of California, Los Angeles, 570 Westwood Plaza, Los Angeles, California 90095, United States
| | - Christopher Wang
- Department of Molecular and Medical Pharmacology and Crump Institute for Molecular Imaging, David Geffen School of Medicine at University of California, Los Angeles, 570 Westwood Plaza, Los Angeles, California 90095, United States
| | - R Michael van Dam
- Department of Molecular and Medical Pharmacology and Crump Institute for Molecular Imaging, David Geffen School of Medicine at University of California, Los Angeles, 570 Westwood Plaza, Los Angeles, California 90095, United States
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Ballard ME, Mandelkern MA, Monterosso JR, Hsu E, Robertson CL, Ishibashi K, Dean AC, London ED. Low Dopamine D2/D3 Receptor Availability is Associated with Steep Discounting of Delayed Rewards in Methamphetamine Dependence. Int J Neuropsychopharmacol 2015; 18:pyu119. [PMID: 25603861 PMCID: PMC4540098 DOI: 10.1093/ijnp/pyu119] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/11/2014] [Accepted: 12/19/2014] [Indexed: 01/27/2023] Open
Abstract
BACKGROUND Individuals with substance use disorders typically exhibit a predilection toward instant gratification with apparent disregard for the future consequences of their actions. Indirect evidence suggests that low dopamine D2-type receptor availability in the striatum contributes to the propensity of these individuals to sacrifice long-term goals for short-term gain; however, this possibility has not been tested directly. We investigated whether striatal D2/D3 receptor availability is negatively correlated with the preference for smaller, more immediate rewards over larger, delayed alternatives among research participants who met DSM-IV criteria for methamphetamine (MA) dependence. METHODS Fifty-four adults (n = 27 each: MA-dependent, non-user controls) completed the Kirby Monetary Choice Questionnaire, and underwent positron emission tomography scanning with [(18)F]fallypride. RESULTS MA users displayed steeper temporal discounting (p = 0.030) and lower striatal D2/D3 receptor availability (p < 0.0005) than controls. Discount rate was negatively correlated with striatal D2/D3 receptor availability, with the relationship reaching statistical significance in the combined sample (r = -0.291, p = 0.016) and among MA users alone (r = -0.342, p = 0.041), but not among controls alone (r = -0.179, p = 0.185); the slopes did not differ significantly between MA users and controls (p = 0.5). CONCLUSIONS These results provide the first direct evidence of a link between deficient D2/D3 receptor availability and steep temporal discounting. This finding fits with reports that low striatal D2/D3 receptor availability is associated with a higher risk of relapse among stimulant users, and may help to explain why some individuals choose to continue using drugs despite knowledge of their eventual negative consequences. Future research directions and therapeutic implications are discussed.
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Affiliation(s)
- Michael E. Ballard
- *Present address: Department of Neurology, University of California San Francisco, San Francisco, CA; Veterans Affairs Northern California Healthcare System, Martinez, CA
| | | | | | | | | | - Kenji Ishibashi
- †Present address: Research Team for Neuroimaging, Tokyo Metropolitan Institute of Gerontology, Tokyo, Japan
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Sethi SK, Varshney R, Rangaswamy S, Chadha N, Hazari PP, Kaul A, Chuttani K, Milton MD, Mishra AK. Design, synthesis and preliminary evaluation of a novel SPECT DTPA-bis-triazaspirodecanone conjugate for D2receptor imaging. RSC Adv 2014. [DOI: 10.1039/c4ra07004f] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
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Ishibashi K, Robertson CL, Mandelkern MA, Morgan AT, London ED. The simplified reference tissue model with 18F-fallypride positron emission tomography: choice of reference region. Mol Imaging 2014; 12. [PMID: 24447617 DOI: 10.2310/7290.2013.00065] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The development of high-affinity radiotracers for positron emission tomography (PET) has allowed for quantification of dopamine receptors in extrastriatal and striatal regions of the brain. As these new radiotracers have distinctly different kinetic properties than their predecessors, it is important to examine the suitability of kinetic models to represent their uptake, distribution, and in vivo washout. Using the simplified reference tissue model, we investigated the influence of reference region choice on the striatal binding potential of 18F-fallypride, a high-affinity dopamine D2/D3 receptor ligand. We compared the use of the visual cortex and a white matter region (superior longitudinal fasciculus) to the cerebellum, a commonly used reference tissue, in a PET-fallypride study of healthy and methamphetamine-dependent subjects. Compared to the cerebellum, use of the visual cortex produced significantly greater sample variance in binding potential relative to nondisplaceable uptake (BP(ND)). Use of the white matter region was associated with BP(ND) values and sample variance similar to those obtained with the cerebellum and a larger effect size for the group differences in striatal BP(ND) between healthy and methamphetamine-dependent subjects. Our results do not support the use of the visual cortex as a reference region in 18F-fallypride studies and suggest that white matter may be a reasonable alternative to the cerebellum as it displays similar statistical and kinetic properties.
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Quantitative, noninvasive, in vivo longitudinal monitoring of gene expression in the brain by co-AAV transduction with a PET reporter gene. MOLECULAR THERAPY-METHODS & CLINICAL DEVELOPMENT 2014; 1:14016. [PMID: 26015960 PMCID: PMC4362377 DOI: 10.1038/mtm.2014.16] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/18/2014] [Accepted: 03/09/2014] [Indexed: 01/06/2023]
Abstract
In vivo imaging of vector transgene expression would be particularly valuable for repetitive monitoring of therapy in the brain, where invasive tissue sampling is contraindicated. We evaluated adeno-associated virus vector expression of a dopamine-2 receptor (D2R) mutant (D2R80A) by positron emission tomography in the brains of mice and cats. D2R80A is inactivated for intracellular signaling and binds subphysiologic amounts of the radioactive [18F]-fallypride analog of dopamine. The [18F]-fallypride signal bound to D2R80A in the injection site was normalized to the signal from endogenous D2R in the striatum and showed stable levels of expression within individual animals. A separate adeno-associated virus type 1 vector with identical gene expression control elements, expressing green fluorescent protein or a therapeutic gene, was coinjected with the D2R80A vector at equal doses into specific sites. Both transgenes had similar levels of gene expression by immunohistochemistry, in situ hybridization, and quantitative PCR assays, demonstrating that D2R80A is a faithful surrogate measure for expression of a gene of interest. This dual vector approach allows the D2R80A gene to be used with any therapeutic gene and to be injected into a single site for monitoring while the therapeutic gene can be distributed more widely as needed in each disease.
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Diepenbroek C, van der Plasse G, Eggels L, Rijnsburger M, Feenstra MGP, Kalsbeek A, Denys D, Fliers E, Serlie MJ, la Fleur SE. Alterations in blood glucose and plasma glucagon concentrations during deep brain stimulation in the shell region of the nucleus accumbens in rats. Front Neurosci 2013; 7:226. [PMID: 24339800 PMCID: PMC3857552 DOI: 10.3389/fnins.2013.00226] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2013] [Accepted: 11/06/2013] [Indexed: 12/24/2022] Open
Abstract
Deep brain stimulation (DBS) of the nucleus accumbens (NAc) is an effective therapy for obsessive compulsive disorder (OCD) and is currently under investigation as a treatment for eating disorders. DBS of this area is associated with altered food intake and pharmacological treatment of OCD is associated with the risk of developing type 2 diabetes. Therefore we examined if DBS of the NAc-shell (sNAc) influences glucose metabolism. Male Wistar rats were subjected to DBS, or sham stimulation, for a period of 1 h. To assess the effects of stimulation on blood glucose and glucoregulatory hormones, blood samples were drawn before, during and after stimulation. Subsequently, all animals were used for quantitative assessment of Fos immunoreactivity in the lateral hypothalamic area (LHA) using computerized image analysis. DBS of the sNAc rapidly increased plasma concentrations of glucagon and glucose while sham stimulation and DBS outside the sNAc were ineffective. In addition, the increase in glucose was dependent on DBS intensity. In contrast, the DBS-induced increase in plasma corticosterone concentrations was independent of intensity and region, indicating that the observed DBS-induced metabolic changes were not due to corticosterone release. Stimulation of the sNAc with 200 μA increased Fos immunoreactivity in the LHA compared to sham or 100 μA stimulated animals. These data show that DBS of the sNAc alters glucose metabolism in a region- and intensity- dependent manner in association with neuronal activation in the LHA. Moreover, these data illustrate the need to monitor changes in glucose metabolism during DBS-treatment of OCD patients.
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Affiliation(s)
- Charlene Diepenbroek
- Department of Endocrinology and Metabolism, Academic Medical Center, University of Amsterdam Amsterdam, Netherlands
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Hillmer AT, Wooten DW, Slesarev MS, Ahlers EO, Barnhart TE, Schneider ML, Mukherjee J, Christian BT. Measuring α4β2* nicotinic acetylcholine receptor density in vivo with [(18)F]nifene PET in the nonhuman primate. J Cereb Blood Flow Metab 2013; 33:1806-14. [PMID: 23942367 PMCID: PMC3824181 DOI: 10.1038/jcbfm.2013.136] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/04/2013] [Revised: 06/07/2013] [Accepted: 07/05/2013] [Indexed: 11/09/2022]
Abstract
[(18)F]Nifene is an agonist PET radioligand developed to image α4β2* nicotinic acetylcholine receptors (nAChRs). This work aims to quantify the receptor density (Bmax) of α4β2* nAChRs and the in vivo (apparent) dissociation constant (KDapp) of [(18)F]nifene. Multiple-injection [(18)F]nifene experiments with varying cold nifene masses were conducted on four rhesus monkeys with a microPET P4 scanner. Compartment modeling techniques were used to estimate regional Bmax values and a global value of KDapp. The fast kinetic properties of [(18)F]nifene also permitted alternative estimates of Bmax and KDapp at transient equilibrium with the same experimental data using Scatchard-like methodologies. Averaged across subjects, the compartment modeling analysis yielded Bmax values of 4.8±1.4, 4.3±1.0, 1.2±0.4, and 1.2±0.3 pmol/mL in the regions of antereoventral thalamus, lateral geniculate, frontal cortex, and subiculum, respectively. The KDapp of nifene was 2.4±0.3 pmol/mL. The Scatchard analysis based on graphical evaluation of the data after transient equilibrium yielded Bmax estimations comparable to the modeling results with a positive bias of 28%. These findings show the utility of [(18)F]nifene for measuring α4β2* nAChR Bmax in vivo in the rhesus monkey with a single PET experiment.
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Affiliation(s)
- Ansel T Hillmer
- 1] Department of Medical Physics, University of Wisconsin-Madison, Madison, Wisconsin, USA [2] Waisman Laboratory for Brain Imaging and Behavior, University of Wisconsin-Madison, Madison, Wisconsin, USA
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30
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Wooten DW, Hillmer AT, Moirano JM, Tudorascu DL, Ahlers EO, Slesarev MS, Barnhart TE, Mukherjee J, Schneider ML, Christian BT. 5-HT1A sex based differences in Bmax, in vivo KD, and BPND in the nonhuman primate. Neuroimage 2013; 77:125-32. [PMID: 23537936 DOI: 10.1016/j.neuroimage.2013.03.027] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2012] [Revised: 02/27/2013] [Accepted: 03/13/2013] [Indexed: 10/27/2022] Open
Abstract
UNLABELLED Serotonin (5-HT) dysfunction has been implicated in neuropsychiatric illnesses and may play a pivotal role in the differential prevalence of depression between the sexes. Previous PET studies have revealed sex-based differences in 5-HT1A binding potential (BPND). The binding potential is a function of the radioligand-receptor affinity (1/KDapp), and receptor density (Bmax). In this work, we use a multiple-injection (MI) PET protocol and the 5-HT1A receptor antagonist, [(18)F]mefway, to compare sex-based differences of in vivo affinity, Bmax, and BPND in rhesus monkeys. METHODS PET [(18)F]mefway studies were performed on 17 (6m, 11f) rhesus monkeys using a 3-injection protocol that included partial saturation injections of mefway. Compartmental modeling was performed using a model to account for non-tracer doses of mefway for the estimation of KDapp and Bmax. BPND estimates were also acquired from the first injection (high specific activity [(18)F]mefway, 90-minute duration) for comparison using the cerebellum (CB) as a reference region. Regions of interest were selected in 5-HT1A binding regions of the hippocampus (Hp), dorsal anterior cingulate cortex (dACC), amygdala (Am), and raphe nuclei (RN). RESULTS Female subjects displayed significantly (*p<0.05) lower KDapp in the Hp (-32%), Am (-38%), and RN (-37%). Only the Hp displayed significant differences in Bmax with females having a Bmax of -29% compared to males. Male subjects demonstrated significantly lower BPND measurements in the Am (14%) and RN (29%). CONCLUSION These results suggest that the higher BPND values found in females are the result of lower [(18)F]mefway KDapp. Although a more experimentally complex measurement, separate assay of KDapp and Bmax provides a more sensitive measure than BPND to identify the underlying differences between females and males in 5-HT1A function.
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Affiliation(s)
- Dustin W Wooten
- Department of Medical Physics, University of Wisconsin-Madison, WI 53705, USA.
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Peyronneau MA, Saba W, Goutal S, Kuhnast B, Dollé F, Bottlaender M, Valette H. [(18)F]Fallypride: metabolism studies and quantification of the radiotracer and its radiometabolites in plasma using a simple and rapid solid-phase extraction method. Nucl Med Biol 2013; 40:887-95. [PMID: 23891202 DOI: 10.1016/j.nucmedbio.2013.06.003] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2013] [Revised: 05/22/2013] [Accepted: 06/13/2013] [Indexed: 11/16/2022]
Abstract
INTRODUCTION [(18)F]Fallypride, a fluorinated and substituted benzamide with high affinity for D2/D3 receptors, is a useful PET radioligand for the study of striatal/extrastriatal areas. Since [(18)F]fallypride is extensively metabolized in vivo and since PET examinations are long lasting in humans, the rapid measurement of the unchanged radiotracer in plasma is essential for the quantification of images. The present study aims: i) to evaluate if the radiometabolites of [(18)F]fallypride cross the blood-brain barrier in rodents, ii) to identify these radiometabolites in baboon plasma and iii) to develop a rapid solid phase extraction method (SPE) suitable for human applications to quantify both [(18)F]fallypride and its radiometabolites in plasma. METHODS The metabolites P450-dependant in rat and human liver microsomes were characterized by LC-MS-MS and compared to those detected in vivo. Sequential solvent elution on Oasis®-MCX-SPE cartridges was used to quantify [(18)F]fallypride and its radiometabolites. RESULT In rat microsomal incubations, five metabolites generated upon N/O-dealkylation or hydroxylation at the pyrrolidine and/or at the benzamide moiety were identified. No radiometabolite was detected in the rat brain. N-dealkylated and hydroxylated derivatives were detected in human microsomal incubations as well as in baboon plasma. The use of SPE (total recovery 100.2%± 2.8%, extraction yield 95.5%± 0.3%) allowed a complete separation of [(18)F]fallypride from its radiometabolites in plasma and evaluate [(18)F]fallypride at 150 min pi to be 22%± 5% of plasma radioactivity. CONCLUSIONS The major in vivo radiometabolites of [(18)F]fallypride were produced by N-dealkylation and hydroxylation. Allowing the rapid analysis of multiple plasma samples, SPE is a method of choice for the determination of [(18)F]fallypride until late images required for quantitative PET imaging in humans.
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Vulnerability to psychotogenic effects of ketamine is associated with elevated D2/3-receptor availability. Int J Neuropsychopharmacol 2013; 16:745-54. [PMID: 22906553 DOI: 10.1017/s1461145712000764] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
Previous positron emission tomography (PET) studies employing competition paradigms have shown either no change or substantial declines in striatal [(11)C]-raclopride binding after challenge with psychotogenic doses of the N-methyl-D-aspartate antagonist ketamine. We sought to probe the relationship between the severity of ketamine-induced psychotic symptoms and altered dopamine D(2/3) receptor availability throughout brain using the high affinity ligand [(18)F]-fallypride (FP). PET recordings were obtained in a group of 10 healthy, young male volunteers, in a placebo condition, and in the course of an infusion with ketamine at a psychotomimetic dose. Administration of the Positive and Negative Syndrome Scale and the Thought and Language Index in both conditions revealed a substantial emergence of mainly negative symptoms of schizophrenia, persisting until the end of the 3 h PET recordings. The baseline FP binding in cortex, caudate nucleus and other brain regions was highly predictive of the individual severity of psychotic symptoms in the ketamine condition. However, there was no evidence of ketamine-evoked reductions in FP binding. In the context of earlier findings, we speculate that high baseline D(2/3)-receptor availability may impart benefits with regard to cognitive flexibility, but increases the risk of maladaptive information processing in the face of environmental stresses and challenges.
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Xu J, Vangveravong S, Li S, Fan J, Jones LA, Cui J, Wang R, Tu Z, Chu W, Perlmutter JS, Mach RH. Positron emission tomography imaging of dopamine D2 receptors using a highly selective radiolabeled D2 receptor partial agonist. Neuroimage 2013; 71:168-74. [PMID: 23333701 DOI: 10.1016/j.neuroimage.2013.01.007] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2012] [Revised: 12/19/2012] [Accepted: 01/08/2013] [Indexed: 11/16/2022] Open
Abstract
A series of microPET imaging studies were conducted in anesthetized rhesus monkeys using the dopamine D2-selective partial agonist, [(11)C]SV-III-130. There was a high uptake in regions of brain known to express a high density of D2 receptors under baseline conditions. Rapid displacement in the caudate and putamen, but not in the cerebellum, was observed after injection of the dopamine D2/3 receptor nonselective ligand S(-)-eticlopride at a low dosage (0.025mg/kg/i.v.); no obvious displacement in the caudate, putamen and cerebellum was observed after the treatment with a dopamine D3 receptor selective ligand WC-34 (0.1mg/kg/i.v.). Pretreatment with lorazepam (1mg/kg, i.v. 30min) to reduce endogenous dopamine prior to tracer injection resulted in unchanged binding potential (BP) values, a measure of D2 receptor binding in vivo, in the caudate and putamen. d-Amphetamine challenge studies indicate that there is a significant displacement of [(11)C]SV-III-130 by d-Amphetamine-induced increases in synaptic dopamine levels.
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Affiliation(s)
- Jinbin Xu
- Department of Radiology, Washington University School of Medicine, 510 S. Kingshighway Blvd., St. Louis, MO 63110, USA
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Cumming P, Xiong G, la Fougère C, Rominger A, Bartenstein P, Buchholz HG, Piel M, Rösch F, Gründer G, Vernaleken I. Surrogate markers for cerebral blood flow correlate with [¹⁸F]-fallypride binding potential at dopamine D(2/3) receptors in human striatum. Synapse 2013; 67:199-203. [PMID: 23239525 DOI: 10.1002/syn.21630] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2012] [Revised: 12/05/2012] [Accepted: 12/07/2012] [Indexed: 12/29/2022]
Abstract
Positron emission tomography (PET) with the high affinity dopamine D(2/3) receptor ligand [¹⁸F]-fallypride affords estimates of the binding potential (BP(ND) ) in extra-striatal regions of low receptor abundance, but the sufficient recording time for accurate measurements in striatum has been called into question. We have earlier argued that transient equilibrium measurements are obtained in striatum with [¹⁸F]-fallypride PET recordings of 3 h duration, which may be the practical limit for clinical investigations without interrupted scanning. However, the high extraction fraction of [¹⁸F]-fallypride predicts flow-dependence of tracer delivery to brain, which may be a source of variance of the apparent BP(ND) in regions of high binding. To test this prediction, we conducted a retrospective analysis of [¹⁸F]-fallypride PET data from a group of 50 healthy volunteers (age 18-58 years [mean ± SD: 32.6 ± 10.6), who had participated in clinical studies without arterial input measurements. We used the initial 120-s integral (AUC) of the venous confluence (VC) as a surrogate marker for cerebral blood flow (CBF) and tested for correlations between regional estimates of BP(ND) calculated by the simplified reference tissue model (SRTM) and the individual VC-AUC. The magnitude of BP(ND) in a high binding region (putamen), but not in a low binding region (thalamus) correlated positively with VC-AUC, suggesting that approximately 9% of the variance in the [¹⁸F]-fallypride BP(ND) in putamen can be attributed to individual differences in this surrogate marker for CBF, a contribution equal in magnitude to the effects of age on BP(ND) in putamen of the present healthy control group.
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Affiliation(s)
- Paul Cumming
- Department of Nuclear Medicine, Ludwig-Maximilian University, Munich, Germany
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Vandehey NT, O'Neil JP, Slowey AJ, Boutchko R, Druhan JL, Moses WW, Nico PS. Monitoring Tc dynamics in a bioreduced sediment: an investigation with gamma camera imaging of (99m)Tc-pertechnetate and (99m)Tc-DTPA. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2012; 46:12583-12590. [PMID: 23078357 DOI: 10.1021/es302313h] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
We demonstrate the utility of nuclear medical imaging technologies and a readily available radiotracer, [(99m)Tc]TcO(4)(-), for the noninvasive monitoring of Fe(II) production in acetate-stimulated sediments from Old Rifle, CO, USA. Microcosms consisting of sediment in artificial groundwater media amended with acetate were probed by repeated injection of radiotracer over three weeks. Gamma camera imaging was used to noninvasively quantify the rate and extent of [(99m)Tc]TcO(4)(-) partitioning from solution to sediment. Aqueous Fe(II) and sediment-associated Fe(II) were also measured and correlated with the observed tracer behavior. For each injection of tracer, curves of (99m)Tc concentration in solution vs time were fitted to an analytic function that accounts for both the observed rate of sedimentation as well as the rate of (99m)Tc association with the sediment. The rate and extent of (99m)Tc association with the biostimulated sediment correlated well with the production of Fe(II), and a mechanism of [(99m)Tc]TcO(4)(-) reduction via reaction with surface-bound Fe(II) to form an immobile Tc(IV) species was inferred. After three weeks of bioreduction, a subset of microcosms was aerated in order to reoxidize the Fe(II) to Fe(III), which also destroyed the affinity of the [(99m)Tc]TcO(4)(-) for the sediments. However, within 3 days postoxidation, the rate of Tc(VII) reduction was faster than immediately before oxidation implying a rapid return to more extensive bioreduction. Furthermore, aeration soon after a tracer injection showed that sediment-bound Tc(IV) is rapidly resolubilized to Tc(VII). In contrast to the [(99m)Tc]TcO(4)(-), a second commercially available tracer, (99m)Tc-DTPA (diethylenetriaminepentaacetic acid), had minimal association with sediment in both controls and biostimulated sediments. These experiments show the promise of [(99m)Tc]TcO(4)(-) and (99m)Tc-DTPA as noninvasive imaging probes for a redox-sensitive radiotracer and a conservative flow tracer, respectively.
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Affiliation(s)
- Nicholas T Vandehey
- Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, California, USA.
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Striatal dopamine D₂/D₃ receptors mediate response inhibition and related activity in frontostriatal neural circuitry in humans. J Neurosci 2012; 32:7316-24. [PMID: 22623677 DOI: 10.1523/jneurosci.4284-11.2012] [Citation(s) in RCA: 181] [Impact Index Per Article: 15.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Impulsive behavior is thought to reflect a traitlike characteristic that can have broad consequences for an individual's success and well-being, but its neurobiological basis remains elusive. Although striatal dopamine D₂-like receptors have been linked with impulsive behavior and behavioral inhibition in rodents, a role for D₂-like receptor function in frontostriatal circuits mediating inhibitory control in humans has not been shown. We investigated this role in a study of healthy research participants who underwent positron emission tomography with the D₂/D₃ dopamine receptor ligand [¹⁸F]fallypride and BOLD fMRI while they performed the Stop-signal Task, a test of response inhibition. Striatal dopamine D₂/D₃ receptor availability was negatively correlated with speed of response inhibition (stop-signal reaction time) and positively correlated with inhibition-related fMRI activation in frontostriatal neural circuitry. Correlations involving D₂/D₃ receptor availability were strongest in the dorsal regions (caudate and putamen) of the striatum, consistent with findings of animal studies relating dopamine receptors and response inhibition. The results suggest that striatal D₂-like receptor function in humans plays a major role in the neural circuitry that mediates behavioral control, an ability that is essential for adaptive responding and is compromised in a variety of common neuropsychiatric disorders.
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Wooten DW, Hillmer AT, Moirano JM, Ahlers EO, Slesarev M, Barnhart TE, Mukherjee J, Schneider ML, Christian BT. Measurement of 5-HT(1A) receptor density and in-vivo binding parameters of [(18)F]mefway in the nonhuman primate. J Cereb Blood Flow Metab 2012; 32:1546-58. [PMID: 22472611 PMCID: PMC3421091 DOI: 10.1038/jcbfm.2012.43] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The goal of this work was to characterize the in-vivo behavior of [(18)F]mefway as a suitable positron emission tomography (PET) radiotracer for the assay of 5-hydroxytryptamine(1A) (5-HT(1A)) receptor density (B(max)). Six rhesus monkeys were studied using a multiple-injection (M-I) protocol consisting of three sequential bolus injections of [(18)F]mefway. Injection times and amounts of unlabeled mefway were optimized for the precise measurement of B(max) and specific binding parameters k(off) and k(on) for estimation of apparent K(D). The PET time series were acquired for 180 minutes with arterial sampling performed throughout. Compartmental analysis using the arterial input function was performed to obtain estimates for K(1), k(2), k(off), B(max), and K(Dapp) in the cerebral cortex and raphe nuclei (RN) using a model that accounted for nontracer doses of mefway. Averaged over subjects, highest binding was seen in the mesial temporal and dorsal anterior cingulate cortices with B(max) values of 42±8 and 36±8 pmol/mL, respectively, and lower values in the superior temporal cortex, RN, and parietal cortex of 24±4, 19±4, and 13±2 pmol/mL, respectively. The K(Dapp) of mefway for the 5-HT(1A) receptor sites was 4.3±1.3 nmol/L. In conclusion, these results show that M-I [(18)F]mefway PET experiments can be used for the in-vivo measurement of 5-HT(1A) receptor density.
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Affiliation(s)
- Dustin W Wooten
- Department of Medical Physics, University of Wisconsin-Madison, Madison, Wisconsin 53705, USA.
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Extrastriatal dopaminergic abnormalities of DA homeostasis in Parkinson's patients with medication-induced pathological gambling: a [11C] FLB-457 and PET study. Neurobiol Dis 2012; 48:519-25. [PMID: 22766031 DOI: 10.1016/j.nbd.2012.06.021] [Citation(s) in RCA: 102] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2012] [Revised: 06/02/2012] [Accepted: 06/22/2012] [Indexed: 12/11/2022] Open
Abstract
Impulse control disorders such as pathological gambling (PG) are a serious and common adverse effect of dopamine (DA) replacement medication in Parkinson's disease (PD). Patients with PG have increased impulsivity and abnormalities in striatal DA, in common with behavioural and substance addictions in the non-PD population. To date, no studies have investigated the role of extrastriatal dopaminergic abnormalities in PD patients with PG. We used the PET radiotracer, [11C] FLB-457, with high-affinity for extrastriatal DA D2/3 receptors. 14 PD patients on DA agonists were imaged while they performed a gambling task involving real monetary reward and a control task. Trait impulsivity was measured with the Barratt Impulsivity Scale (BIS). Seven of the patients had a history of PG that developed subsequent to DA agonist medication. Change in [11C] FLB-457 binding potential (BP) during gambling was reduced in PD with PG patients in the midbrain, where D2/D3 receptors are dominated by autoreceptors. The degree of change in [11C] FLB-457 binding in this region correlated with impulsivity. In the cortex, [11C] FLB-457 BP was significantly greater in the anterior cingulate cortex (ACC) in PD patients with PG during the control task, and binding in this region was also correlated with impulsivity. Our findings provide the first evidence that PD patients with PG have dysfunctional activation of DA autoreceptors in the midbrain and low DA tone in the ACC. Thus, altered striatal and cortical DA homeostasis may incur vulnerability for the development of PG in PD, linked with the impulsive personality trait.
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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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In vivo evidence of deep brain stimulation-induced dopaminergic modulation in Tourette's syndrome. Biol Psychiatry 2012; 71:e11-3. [PMID: 22129758 DOI: 10.1016/j.biopsych.2011.09.035] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/16/2011] [Revised: 09/30/2011] [Accepted: 09/30/2011] [Indexed: 12/15/2022]
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Abstract
The high-affinity radioligand [(18)F]fallypride (FP) is frequently used for quantification of striatal/extrastriatal D(2/3) receptors and the receptor occupancies of antipsychotics (APs). Its 110 minutes half-life allows long scan durations. However, the optimum scan duration is a matter of debate. This investigation focuses on scan-duration-related effects on simplified reference tissue model (SRTM) results and the time point of transient equilibrium in a large sample of dynamic FP positron emission tomography (PET) scans. Fifty drug-free and 50 AP-treated subjects underwent FP-PET scans (180 minutes scan duration). The binding potential (BP(ND)) of the putamen, thalamus, and temporal cortex were calculated using the SRTM and the transient equilibrium model. Furthermore, receptor occupancies were calculated for AP-treated patients. Transient equilibrium in the unblocked putamen occurred after 121±29.6 minutes. The transient equilibrium occurred much earlier in the extrastriatal regions or under AP treatment. Stepwise scan shortening caused BP(ND) underestimations of 0.58% for the first 10-minute reduction (putamen, SRTM), finally reaching 5.76% after 1 hour scan-time reduction. We observed preferential extrastriatal AP binding irrespective of the analytical method. [(18)F]fallypride scan durations of 180 minutes reliably reach equilibrium even in D(2/3)-receptor-rich regions. Moderate reductions in FP scan durations only caused small changes to SRTM results even in receptor-rich regions. Apparently, the D(2/3) receptor occupancy results of APs, especially preferential extrastriatal binding observations, are not relevantly biased by inappropriate scan durations.
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Mach RH, Tu Z, Xu J, Li S, Jones LA, Taylor M, Luedtke RR, Derdeyn CP, Perlmutter JS, Mintun MA. Endogenous dopamine (DA) competes with the binding of a radiolabeled D₃ receptor partial agonist in vivo: a positron emission tomography study. Synapse 2011; 65:724-32. [PMID: 21132811 DOI: 10.1002/syn.20891] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2010] [Accepted: 11/04/2010] [Indexed: 11/08/2022]
Abstract
A series of microPET imaging studies were conducted in anesthetized rhesus monkeys using the dopamine D₃-selective partial agonist, [¹⁸F]5. There was variable uptake in regions of brain known to express a high density of D₃ receptors under baseline conditions. Pretreatment with lorazepam (1 mg/kg, i.v. 30 min) to reduce endogenous dopamine activity before tracer injection resulted in a dramatic increase in uptake in the caudate, putamen, and thalamus, and an increase in the binding potential (BP) values, a measure of D₃ receptor binding in vivo. These data indicate that there is a high level of competition between [¹⁸F]5 and endogenous dopamine for D₃ receptors in vivo.
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Affiliation(s)
- Robert H Mach
- Division of Radiological Sciences, Washington University School of Medicine, Mallinckrodt Institute of Radiology, Missouri 63110, USA.
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Abstract
Parkinson's disease (PD) is a common disorder in which the primary features can be related to dopamine deficiency. Changes on structural imaging are limited, but a wealth of abnormalities can be detected using positron emission tomography, single photon emission computed tomography, or functional magnetic resonance imaging to detect changes in neurochemical pathology or functional connectivity. The changes detected on these studies may reflect the disease process itself and/or compensatory responses to the disease, or they may arise in association with disease- and/or treatment-related complications. This review will focus mainly on neurochemical and metabolic studies and reviews various approaches to the assessment of dopaminergic function as well as the function of other neurotransmitters that may be affected in PD. A number of clinical applications are highlighted, including diagnostic utility, identification of preclinical disease, changes associated with motor and nonmotor complications of PD, and the effects of various therapeutic interventions.
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Affiliation(s)
- A Jon Stoessl
- Pacific Parkinson's Research Centre, University of British Columbia & Vancouver Coastal Health, Vancouver, British Columbia, Canada.
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Quantitative PET imaging of radioligands with slow kinetics in human brain. Eur J Nucl Med Mol Imaging 2010; 37:1613-5. [DOI: 10.1007/s00259-010-1518-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2010] [Accepted: 06/03/2010] [Indexed: 11/25/2022]
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