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Moradi K, Badripour A, Moradi A, Bagheri S, Soltani ZE, Moassefi M, Faghani S, Dehpour AR. Sumatriptan attenuates fear-learning despair induced by social isolation stress in mice: Mediating role of hypothalamic-pituitary-adrenal axis. Psychoneuroendocrinology 2024; 164:107006. [PMID: 38432042 DOI: 10.1016/j.psyneuen.2024.107006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/19/2023] [Revised: 12/28/2023] [Accepted: 02/26/2024] [Indexed: 03/05/2024]
Abstract
OBJECTIVES Research has demonstrated that chronic stress experienced early in life can lead to impairments in memory and learning. These deficits are attributed to an imbalance in the interaction between glucocorticoids, the end product of the hypothalamic-pituitary-adrenal (HPA) axis, and glucocorticoid receptors in brain regions responsible for mediating memory, such as the hippocampus. This imbalance can result in detrimental conditions like neuroinflammation. The aim of this study was to assess the impact of sumatriptan, a selective agonist for 5-HT 1B/1D receptors, on fear learning capabilities in a chronic social isolation stress model in mice, with a particular focus on the role of the HPA axis. METHODS Mice were assigned to two opposing conditions, including social condition (SC) and isolated condition (IC) for a duration of five weeks. All mice underwent passive avoidance test, with their subsequent freezing behavior serving as an indicator of fear retrieval. Mice in the IC group were administered either a vehicle, sumatriptan, GR-127935 (a selective antagonist for 5-HT 1B/1D receptors), or a combination of sumatriptan and GR-127935 during the testing sessions. At the end, all mice were sacrificed and samples of their serum and hippocampus were collected for further analysis. RESULTS Isolation was found to significantly reduce freezing behavior (p<0.001). An increase in the freezing response among IC mice was observed following the administration of varying doses of sumatriptan, as indicated by a one-way ANOVA analysis (p<0.001). However, the mitigating effects of sumatriptan were reversed upon the administration of GR-127935. An ELISA assay conducted before and after the passive avoidance test revealed no significant change in serum corticosterone levels among SC mice. In contrast, a significant increase was observed among IC mice, suggesting hyper-responsiveness of the HPA axis in isolated animals. This hyper-responsiveness was ameliorated following the administration of sumatriptan. Furthermore, both the sumatriptan and SC groups exhibited a similar trend, showing a significant increase in the expression of hippocampal glucocorticoid receptors following the stress of the passive avoidance test. Lastly, the elevated production of inflammatory cytokines (TNF-α, IL-1β) observed following social isolation was attenuated in the sumatriptan group. CONCLUSION Sumatriptan improved fear learning probably through modulation of HPA axis and hippocampus neuroinflammation.
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Affiliation(s)
- Kamyar Moradi
- School of Medicine, Tehran University of Medical Sciences, Tehran, Iran; Brain and Spinal Cord Injury Research Center, Neuroscience Institute, Tehran University of Medical Sciences, Tehran, Iran; Experimental Medicine Research Center, Tehran University of Medical Sciences, Tehran, Iran
| | - Abolfazl Badripour
- School of Medicine, Tehran University of Medical Sciences, Tehran, Iran; Brain and Spinal Cord Injury Research Center, Neuroscience Institute, Tehran University of Medical Sciences, Tehran, Iran; Experimental Medicine Research Center, Tehran University of Medical Sciences, Tehran, Iran
| | - Ali Moradi
- School of Medicine, Tehran University of Medical Sciences, Tehran, Iran
| | - Sayna Bagheri
- School of Medicine, Tehran University of Medical Sciences, Tehran, Iran; Brain and Spinal Cord Injury Research Center, Neuroscience Institute, Tehran University of Medical Sciences, Tehran, Iran; Experimental Medicine Research Center, Tehran University of Medical Sciences, Tehran, Iran
| | - Zahra Ebrahim Soltani
- School of Medicine, Tehran University of Medical Sciences, Tehran, Iran; Experimental Medicine Research Center, Tehran University of Medical Sciences, Tehran, Iran
| | - Mana Moassefi
- School of Medicine, Tehran University of Medical Sciences, Tehran, Iran; Brain and Spinal Cord Injury Research Center, Neuroscience Institute, Tehran University of Medical Sciences, Tehran, Iran
| | - Shahriar Faghani
- School of Medicine, Tehran University of Medical Sciences, Tehran, Iran; Brain and Spinal Cord Injury Research Center, Neuroscience Institute, Tehran University of Medical Sciences, Tehran, Iran
| | - Ahmad Reza Dehpour
- Experimental Medicine Research Center, Tehran University of Medical Sciences, Tehran, Iran; Department of Pharmacology, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran.
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Smart K, Zheng MQ, Holden D, Felchner Z, Zhang L, Han Y, Ropchan J, Carson RE, Vasdev N, Huang Y. In Vivo Imaging and Kinetic Modeling of Novel Glycogen Synthase Kinase-3 Radiotracers [ 11C]OCM-44 and [ 18F]OCM-50 in Non-Human Primates. Pharmaceuticals (Basel) 2023; 16:194. [PMID: 37259346 PMCID: PMC9959234 DOI: 10.3390/ph16020194] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2022] [Revised: 01/21/2023] [Accepted: 01/24/2023] [Indexed: 11/19/2023] Open
Abstract
Glycogen synthase kinase 3 (GSK-3) is a potential therapeutic target for a range of neurodegenerative and psychiatric disorders. The goal of this work was to evaluate two leading GSK-3 positron emission tomography (PET) radioligands, [11C]OCM-44 and [18F]OCM-50, in non-human primates to assess their potential for clinical translation. A total of nine PET scans were performed with the two radiotracers using arterial blood sampling in adult rhesus macaques. Brain regional time-activity curves were extracted and fitted with one- and two-tissue compartment models using metabolite-corrected arterial input functions. Target selectivity was assessed after pre-administration of the GSK-3 inhibitor PF-04802367 (PF-367, 0.03-0.25 mg/kg). Both radiotracers showed good brain uptake and distribution throughout grey matter. [11C]OCM-44 had a free fraction in the plasma of 3% at baseline and was metabolized quickly. The [11C]OCM-44 volume of distribution (VT) values in the brain increased with time; VT values from models fitted to truncated 60-min scan data were 1.4-2.9 mL/cm3 across brain regions. The plasma free fraction was 0.6% for [18F]OCM-50 and VT values (120-min) were 0.39-0.87 mL/cm3 in grey matter regions. After correcting for plasma free fraction increases during blocking scans, reductions in regional VT indicated >80% target occupancy by 0.1 mg/kg of PF-367 for both radiotracers, supporting target selectivity in vivo. [11C]OCM-44 and [18F]OCM-50 warrant further evaluation as radioligands for imaging GSK-3 in the brain, though radio-metabolite accumulation may confound image analysis.
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Affiliation(s)
- Kelly Smart
- Brain Health Imaging Centre, Centre for Addiction and Mental Health, 250 College St., Toronto, ON M5T 1R8, Canada
- Department of Psychiatry, University of Toronto, 250 College St., Toronto, ON M5T 1R8, Canada
- Yale PET Center, Yale School of Medicine, 801 Howard Ave., New Haven, CT 06519, USA
| | - Ming-Qiang Zheng
- Yale PET Center, Yale School of Medicine, 801 Howard Ave., New Haven, CT 06519, USA
| | - Daniel Holden
- Yale PET Center, Yale School of Medicine, 801 Howard Ave., New Haven, CT 06519, USA
| | - Zachary Felchner
- Yale PET Center, Yale School of Medicine, 801 Howard Ave., New Haven, CT 06519, USA
| | - Li Zhang
- Yale PET Center, Yale School of Medicine, 801 Howard Ave., New Haven, CT 06519, USA
| | - Yanjiang Han
- Yale PET Center, Yale School of Medicine, 801 Howard Ave., New Haven, CT 06519, USA
- Nanfang Hospital, Southern Medical University, 1838 Guangzhou Blvd North, Guangzhou 510515, China
| | - Jim Ropchan
- Yale PET Center, Yale School of Medicine, 801 Howard Ave., New Haven, CT 06519, USA
| | - Richard E. Carson
- Yale PET Center, Yale School of Medicine, 801 Howard Ave., New Haven, CT 06519, USA
| | - Neil Vasdev
- Brain Health Imaging Centre, Centre for Addiction and Mental Health, 250 College St., Toronto, ON M5T 1R8, Canada
- Department of Psychiatry, University of Toronto, 250 College St., Toronto, ON M5T 1R8, Canada
| | - Yiyun Huang
- Yale PET Center, Yale School of Medicine, 801 Howard Ave., New Haven, CT 06519, USA
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3
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Fu H, Rong J, Chen Z, Zhou J, Collier T, Liang SH. Positron Emission Tomography (PET) Imaging Tracers for Serotonin Receptors. J Med Chem 2022; 65:10755-10808. [PMID: 35939391 DOI: 10.1021/acs.jmedchem.2c00633] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Serotonin (5-hydroxytryptamine, 5-HT) and 5-HT receptors (5-HTRs) have crucial roles in various neuropsychiatric disorders and neurodegenerative diseases, making them attractive diagnostic and therapeutic targets. Positron emission tomography (PET) is a noninvasive nuclear molecular imaging technique and is an essential tool in clinical diagnosis and drug discovery. In this context, numerous PET ligands have been developed for "visualizing" 5-HTRs in the brain and translated into human use to study disease mechanisms and/or support drug development. Herein, we present a comprehensive repertoire of 5-HTR PET ligands by focusing on their chemotypes and performance in PET imaging studies. Furthermore, this Perspective summarizes recent 5-HTR-focused drug discovery, including biased agonists and allosteric modulators, which would stimulate the development of more potent and subtype-selective 5-HTR PET ligands and thus further our understanding of 5-HTR biology.
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Affiliation(s)
- Hualong Fu
- Key Laboratory of Radiopharmaceuticals, Ministry of Education, College of Chemistry, Beijing Normal University, Beijing 100875, China
| | - Jian Rong
- Division of Nuclear Medicine and Molecular Imaging, Massachusetts General Hospital, Boston, Massachusetts 02114, United States.,Department of Radiology, Harvard Medical School, Boston, Massachusetts 02115, United States
| | - Zhen Chen
- Jiangsu Co-Innovation Center of Efficient Processing and Utilization of Forest Resources, International Innovation Center for Forest Chemicals and Materials, College of Chemical Engineering, Nanjing Forestry University, Nanjing, Jiangsu 210037, China
| | - Jingyin Zhou
- Key Laboratory of Radiopharmaceuticals, Ministry of Education, College of Chemistry, Beijing Normal University, Beijing 100875, China
| | - Thomas Collier
- Division of Nuclear Medicine and Molecular Imaging, Massachusetts General Hospital, Boston, Massachusetts 02114, United States.,Department of Radiology, Harvard Medical School, Boston, Massachusetts 02115, United States
| | - Steven H Liang
- Division of Nuclear Medicine and Molecular Imaging, Massachusetts General Hospital, Boston, Massachusetts 02114, United States.,Department of Radiology, Harvard Medical School, Boston, Massachusetts 02115, United States
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4
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Baldassarri SR, Park E, Finnema SJ, Planeta B, Nabulsi N, Najafzadeh S, Ropchan J, Huang Y, Hannestad J, Maloney K, Bhagwagar Z, Carson RE. Inverse changes in raphe and cortical 5-HT 1B receptor availability after acute tryptophan depletion in healthy human subjects. Synapse 2020; 74:e22159. [PMID: 32324935 DOI: 10.1002/syn.22159] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2019] [Revised: 04/08/2020] [Accepted: 04/19/2020] [Indexed: 11/07/2022]
Abstract
Serotonergic neurotransmission plays a key role in the pathophysiology and treatment of various neuropsychiatric diseases. The purpose of this study was to investigate changes in serotonergic neurotransmission after acute tryptophan depletion (ATD) using positron emission tomography (PET) with [11 C]P943, a 5-HT1B receptor radioligand previously shown to be sensitive to changes in 5-HT. Five healthy subjects were scanned on a high resolution PET scanner twice on the same day, before and approximately 5 hours after ingesting capsules containing an amino acid mixture that lacks tryptophan. For each scan, emission data were acquired for 120 min after intravenous bolus injection of [11 C]P943. Binding potential (BPND ) values were estimated from parametric images using the second version of the multilinear reference tissue model (MRTM2, t* = 20 min) with cerebellar grey matter used as a reference region. The change in [11 C]P943 binding (ΔBPND , %) was calculated as (BPND,post - BPND,pre )/(BPND,pre ) × 100, and correlation analysis was performed to measure linear associations of ΔBPND between raphe and other regions of interest (ROIs). ΔBPND ranged from -6% to 45% in the raphe, with positive values indicating reduced competition from 5-HT. In cortical regions, ΔBPND ranged from -28% to 7%. While these changes did not reach significance, there were significant negative correlations of ΔBPND of the raphe with those of cerebral cortical regions and the thalamus (e.g., r = -.96, p = .011 for average cortex). These findings support the hypothesis that raphe serotonin is a critical modulator of cortical serotonin release via projecting neurons in healthy human subjects.
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Affiliation(s)
- Stephen R Baldassarri
- Section of Pulmonary, Critical Care, and Sleep Medicine, Department of Internal Medicine, Yale School of Medicine, New Haven, CT, USA
| | - Eunkyung Park
- Department of Radiology and Biomedical Imaging, PET Center, Yale School of Medicine, New Haven, CT, USA.,Division of Nuclear Medicine, Department of Radiology, University of Iowa Hospitals and Clinics, Iowa City, IA, USA
| | - Sjoerd J Finnema
- Department of Radiology and Biomedical Imaging, PET Center, Yale School of Medicine, New Haven, CT, USA
| | - Beata Planeta
- Department of Radiology and Biomedical Imaging, PET Center, Yale School of Medicine, New Haven, CT, USA
| | - Nabeel Nabulsi
- Department of Radiology and Biomedical Imaging, PET Center, Yale School of Medicine, New Haven, CT, USA
| | - Soheila Najafzadeh
- Department of Radiology and Biomedical Imaging, PET Center, Yale School of Medicine, New Haven, CT, USA
| | - Jim Ropchan
- Department of Radiology and Biomedical Imaging, PET Center, Yale School of Medicine, New Haven, CT, USA
| | - Yiyun Huang
- Department of Radiology and Biomedical Imaging, PET Center, Yale School of Medicine, New Haven, CT, USA
| | - Jonas Hannestad
- Department of Psychiatry, Yale School of Medicine, New Haven, CT, USA
| | - Kathleen Maloney
- Department of Psychiatry, Yale School of Medicine, New Haven, CT, USA
| | - Zubin Bhagwagar
- Department of Psychiatry, Yale School of Medicine, New Haven, CT, USA
| | - Richard E Carson
- Department of Radiology and Biomedical Imaging, PET Center, Yale School of Medicine, New Haven, CT, USA
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5
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The chemistry of labeling heterocycles with carbon-11 or fluorine-18 for biomedical imaging. ADVANCES IN HETEROCYCLIC CHEMISTRY 2020. [DOI: 10.1016/bs.aihch.2019.11.005] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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6
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Hammoud DA, Sinharay S, Shah S, Schreiber-Stainthorp W, Maric D, Muthusamy S, Lee DE, Lee CA, Basuli F, Reid WC, Wakim P, Matsuda K, Hirsch V, Nath A, Di Mascio M. Neuroinflammatory Changes in Relation to Cerebrospinal Fluid Viral Load in Simian Immunodeficiency Virus Encephalitis. mBio 2019; 10:e00970-19. [PMID: 31138753 PMCID: PMC6538790 DOI: 10.1128/mbio.00970-19] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2019] [Accepted: 04/29/2019] [Indexed: 01/12/2023] Open
Abstract
The exact cause of neurocognitive dysfunction in HIV-positive patients despite successful control of the infection in the periphery is not completely understood. One suggested mechanism is a vicious cycle of microglial activation and release of proinflammatory chemokines/cytokines that eventually leads to neuronal loss and dysfunction. However, the exact role of microglial activation in the earliest stages of the infection with high cerebrospinal fluid (CSF) viral loads (VL) is unclear. In this study, we imaged the translocator protein (TSPO), a mitochondrial membrane receptor known to be upregulated in activated microglia and macrophages, in rhesus macaques before and multiple times after inoculation with a neurotropic simian immunodeficiency virus (SIV) strain (SIVsm804E), using 18F-DPA714 positron emission tomography (PET). The whole-brain standardized uptake values of TSPO at equilibrium reflecting total binding (SUVT) and binding potentials (BPND) were calculated and correlated with CSF and serum markers of disease, and a corresponding postmortem immunostaining analysis was also performed. SUVT was found to be inversely correlated with both CSF VL and monocyte chemoattractant protein 1 (MCP-1) levels. In SIV-infected macaques with very high CSF VL at necropsy (>106 copies/ml), we found decreased TSPO binding by PET, and this was supported by immunostaining which showed glial and neuronal apoptosis rather than microglial activation. On the other hand, with only moderately elevated CSF VL (∼104 copies/ml), we found increased TSPO binding as well as focal and diffuse microglial activation on immunostaining. Our results in the SIV-infected macaque model provide insights into the relationship between HIV neuropathology and CSF VL at various stages of the disease.IMPORTANCE Neurological and cognitive problems are a common complication of HIV infection and are prevalent even in treated individuals. Although the molecular processes underlying brain involvement with HIV are not completely understood, inflammation is suspected to play a significant role. Our work presents an in vivo assessment of neuroinflammation in an animal model of HIV, the simian immunodeficiency virus (SIV)-infected rhesus macaque. Using positron emission tomography (PET) imaging, we identified changes in brain inflammation after inoculation with SIV over time. Interestingly, we found decreased binding of the PET ligand in the presence of very high cerebrospinal fluid (CSF) viral loads. These findings were supported by immunostaining which showed marked glial loss instead of inflammation. This study provides insight into glial and neuronal changes associated with very high CSF viral load and could reflect similar changes occurring in HIV-infected patients.
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Affiliation(s)
- Dima A Hammoud
- Center for Infectious Disease Imaging, Radiology and Imaging Sciences, Clinical Center, National Institutes of Health, Bethesda, Maryland, USA
| | - Sanhita Sinharay
- Center for Infectious Disease Imaging, Radiology and Imaging Sciences, Clinical Center, National Institutes of Health, Bethesda, Maryland, USA
| | - Swati Shah
- Center for Infectious Disease Imaging, Radiology and Imaging Sciences, Clinical Center, National Institutes of Health, Bethesda, Maryland, USA
| | - William Schreiber-Stainthorp
- Center for Infectious Disease Imaging, Radiology and Imaging Sciences, Clinical Center, National Institutes of Health, Bethesda, Maryland, USA
| | - Dragan Maric
- Division of Intramural Research, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland, USA
| | - Siva Muthusamy
- Center for Infectious Disease Imaging, Radiology and Imaging Sciences, Clinical Center, National Institutes of Health, Bethesda, Maryland, USA
| | - Dianne E Lee
- Center for Infectious Disease Imaging, Radiology and Imaging Sciences, Clinical Center, National Institutes of Health, Bethesda, Maryland, USA
| | - Cheri A Lee
- Laboratory of Molecular Microbiology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, USA
| | - Falguni Basuli
- Imaging Probe Development Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Rockville, Maryland, USA
| | - William C Reid
- Center for Infectious Disease Imaging, Radiology and Imaging Sciences, Clinical Center, National Institutes of Health, Bethesda, Maryland, USA
| | - Paul Wakim
- Biostatistics and Clinical Epidemiology Service, Clinical Center, National Institutes of Health, Bethesda, Maryland, USA
| | - Kenta Matsuda
- Laboratory of Molecular Microbiology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, USA
| | - Vanessa Hirsch
- Laboratory of Molecular Microbiology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, USA
| | - Avindra Nath
- Section of Infections of the Nervous System, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland, USA
| | - Michele Di Mascio
- AIDS Imaging Research Section, Division of Clinical Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, Maryland, USA
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Li S, Zheng MQ, Naganawa M, Gao H, Pracitto R, Shirali A, Lin SF, Teng JK, Ropchan J, Huang Y. Novel Kappa Opioid Receptor Agonist as Improved PET Radiotracer: Development and in Vivo Evaluation. Mol Pharm 2019; 16:1523-1531. [PMID: 30726092 DOI: 10.1021/acs.molpharmaceut.8b01209] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The kappa opioid receptor (KOR) is involved in depression, alcoholism, and drug abuse. The current agonist radiotracer 11C-GR103545 is not ideal for imaging KOR due to its slow tissue kinetics in human. The aim of our project was to develop novel KOR agonist radiotracers with improved imaging properties. A novel compound FEKAP ((( R))-4-(2-(3,4-dichlorophenyl)acetyl)-3-((ethyl(2-fluoroethyl)amino)methyl) piperazine-1-carboxylate) was designed, synthesized, and assayed for in vitro binding affinities. It was then radiolabeled and evaluated in rhesus monkeys. Baseline and blocking scans were conducted on a Focus-220 scanner to assess binding specificity and selectivity. Metabolite-corrected arterial activities over time were measured and used as input functions to analyze the brain regional time-activity curves and derive kinetic and binding parameters with kinetic modeling. FEKAP displayed high KOR binding affinity ( Ki = 0.43 nM) and selectivity (17-fold over mu opioid receptor and 323-fold over delta opioid receptor) in vitro. 11C-FEKAP was prepared in high molar activity (mean of 718 GBq/μmol, n = 19) and >99% radiochemical purity. In monkeys, 11C-FEKAP metabolized fairly fast, with ∼31% of intact parent fraction at 30 min post-injection. In the brain, it exhibited fast and reversible kinetics with good uptake. Pretreatment with the nonselective opioid receptor antagonist naloxone (1 mg/kg) decreased uptake in high binding regions to the level in the cerebellum, and the selective KOR antagonist LY2456302 (0.02 and 0.1 mg/kg) reduced 11C-FEKAP specific binding in a dose-dependent manner. As a measure of specific binding signals, the mean binding potential ( BPND) values of 11C-FEKAP derived from the multilinear analysis-1 (MA1) method were greater than 0.5 for all regions, except for the thalamus. The novel KOR agonist tracer 11C-FEKAP demonstrated binding specificity and selectivity in vivo and exhibited attractive properties of fast tissue kinetics and high specific binding.
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Affiliation(s)
- Songye Li
- PET Center, Department of Radiology and Biomedical Imaging , Yale University School of Medicine , New Haven , Connecticut 06520 , United States
| | - Ming-Qiang Zheng
- PET Center, Department of Radiology and Biomedical Imaging , Yale University School of Medicine , New Haven , Connecticut 06520 , United States
| | - Mika Naganawa
- PET Center, Department of Radiology and Biomedical Imaging , Yale University School of Medicine , New Haven , Connecticut 06520 , United States
| | - Hong Gao
- PET Center, Department of Radiology and Biomedical Imaging , Yale University School of Medicine , New Haven , Connecticut 06520 , United States
| | - Richard Pracitto
- PET Center, Department of Radiology and Biomedical Imaging , Yale University School of Medicine , New Haven , Connecticut 06520 , United States
| | - Anupama Shirali
- PET Center, Department of Radiology and Biomedical Imaging , Yale University School of Medicine , New Haven , Connecticut 06520 , United States
| | - Shu-Fei Lin
- PET Center, Department of Radiology and Biomedical Imaging , Yale University School of Medicine , New Haven , Connecticut 06520 , United States
| | - Jo-Ku Teng
- PET Center, Department of Radiology and Biomedical Imaging , Yale University School of Medicine , New Haven , Connecticut 06520 , United States
| | - Jim Ropchan
- PET Center, Department of Radiology and Biomedical Imaging , Yale University School of Medicine , New Haven , Connecticut 06520 , United States
| | - Yiyun Huang
- PET Center, Department of Radiology and Biomedical Imaging , Yale University School of Medicine , New Haven , Connecticut 06520 , United States
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8
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Chen Z, Jamadar SD, Li S, Sforazzini F, Baran J, Ferris N, Shah NJ, Egan GF. From simultaneous to synergistic MR-PET brain imaging: A review of hybrid MR-PET imaging methodologies. Hum Brain Mapp 2018; 39:5126-5144. [PMID: 30076750 DOI: 10.1002/hbm.24314] [Citation(s) in RCA: 45] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2018] [Revised: 06/25/2018] [Accepted: 07/02/2018] [Indexed: 12/17/2022] Open
Abstract
Simultaneous Magnetic Resonance Imaging (MRI) and Positron Emission Tomography (PET) scanning is a recent major development in biomedical imaging. The full integration of the PET detector ring and electronics within the MR system has been a technologically challenging design to develop but provides capacity for simultaneous imaging and the potential for new diagnostic and research capability. This article reviews state-of-the-art MR-PET hardware and software, and discusses future developments focusing on neuroimaging methodologies for MR-PET scanning. We particularly focus on the methodologies that lead to an improved synergy between MRI and PET, including optimal data acquisition, PET attenuation and motion correction, and joint image reconstruction and processing methods based on the underlying complementary and mutual information. We further review the current and potential future applications of simultaneous MR-PET in both systems neuroscience and clinical neuroimaging research. We demonstrate a simultaneous data acquisition protocol to highlight new applications of MR-PET neuroimaging research studies.
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Affiliation(s)
- Zhaolin Chen
- Monash Biomedical Imaging, Monash University, Clayton, Victoria, Australia.,Department of Electrical and Computer Systems Engineering, Monash University, Clayton, Victoria, Australia
| | - Sharna D Jamadar
- Monash Biomedical Imaging, Monash University, Clayton, Victoria, Australia.,Monash Institute of Cognitive and Clinical Neuroscience, Monash University, Clayton, Victoria, Australia.,Australian Research Council Centre of Excellence for Integrative Brain Function, Monash University, Clayton, Victoria, Australia
| | - Shenpeng Li
- Monash Biomedical Imaging, Monash University, Clayton, Victoria, Australia.,Department of Electrical and Computer Systems Engineering, Monash University, Clayton, Victoria, Australia
| | | | - Jakub Baran
- Monash Biomedical Imaging, Monash University, Clayton, Victoria, Australia.,Department of Biophysics, Faculty of Mathematics and Natural Sciences, University of Rzeszów, Rzeszów, Poland
| | - Nicholas Ferris
- Monash Biomedical Imaging, Monash University, Clayton, Victoria, Australia.,Monash Imaging, Monash Health, Clayton, Victoria, Australia
| | - Nadim Jon Shah
- Monash Biomedical Imaging, Monash University, Clayton, Victoria, Australia.,Institute of Neuroscience and Medicine 4, INM-4, Forschungszentrum, Jülich, Germany
| | - Gary F Egan
- Monash Biomedical Imaging, Monash University, Clayton, Victoria, Australia.,Monash Institute of Cognitive and Clinical Neuroscience, Monash University, Clayton, Victoria, Australia.,Australian Research Council Centre of Excellence for Integrative Brain Function, Monash University, Clayton, Victoria, Australia
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9
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Hazari PP, Pandey A, Chaturvedi S, Mishra AK. New Trends and Current Status of Positron-Emission Tomography and Single-Photon-Emission Computerized Tomography Radioligands for Neuronal Serotonin Receptors and Serotonin Transporter. Bioconjug Chem 2017; 28:2647-2672. [PMID: 28767225 DOI: 10.1021/acs.bioconjchem.7b00243] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The critical role of serotonin (5-hydroxytryptamine; 5-HT) and its receptors (5-HTRs) in the pathophysiology of diverse neuropsychiatric and neurodegenerative disorders render them attractive diagnostic and therapeutic targets for brain disorders. Therefore, the in vivo assessment of binding of 5-HT receptor ligands under a multitude of physiologic and pathologic scenarios may support more-accurate identification of disease and its progression and the patient's response to therapy as well as the screening of novel therapeutic strategies. The present Review aims to focus on the current status of radioligands used for positron-emission tomography (PET) and single-photon-emission computerized tomography (SPECT) imaging of human brain serotonin receptors. We further elaborate upon and emphasize the attributes that qualify a radioligand for theranostics on the basis of its frequency of use in clinics, its benefit to risk assessment in humans, and its continuous evolution, along with the major limitations.
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Affiliation(s)
- Puja Panwar Hazari
- Division of Cyclotron and Radiopharmaceutical Sciences, Institute of Nuclear Medicine and Allied Sciences , Brig S.K. Mazumdar Road, Delhi 110054, India
| | - Ankita Pandey
- Division of Cyclotron and Radiopharmaceutical Sciences, Institute of Nuclear Medicine and Allied Sciences , Brig S.K. Mazumdar Road, Delhi 110054, India
| | - Shubhra Chaturvedi
- Division of Cyclotron and Radiopharmaceutical Sciences, Institute of Nuclear Medicine and Allied Sciences , Brig S.K. Mazumdar Road, Delhi 110054, India
| | - Anil Kumar Mishra
- Division of Cyclotron and Radiopharmaceutical Sciences, Institute of Nuclear Medicine and Allied Sciences , Brig S.K. Mazumdar Road, Delhi 110054, India
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10
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Functional Characterization of 5-HT 1B Receptor Drugs in Nonhuman Primates Using Simultaneous PET-MR. J Neurosci 2017; 37:10671-10678. [PMID: 28972127 DOI: 10.1523/jneurosci.1971-17.2017] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2017] [Revised: 08/24/2017] [Accepted: 09/22/2017] [Indexed: 11/21/2022] Open
Abstract
In the present study, we used a simultaneous PET-MR experimental design to investigate the effects of functionally different compounds (agonist, partial agonist, and antagonist) on 5-HT1B receptor (5-HT1BR) occupancy and the associated hemodynamic responses. In anesthetized male nonhuman primates (n = 3), we used positron emission tomography (PET) imaging with the radioligand [11C]AZ10419369 administered as a bolus followed by constant infusion to measure changes in 5-HT1BR occupancy. Simultaneously, we measured changes in cerebral blood volume (CBV) as a proxy of drug effects on neuronal activity. The 5-HT1BR partial agonist AZ10419369 elicited a dose-dependent biphasic hemodynamic response that was related to the 5-HT1BR occupancy. The magnitude of the response was spatially overlapping with high cerebral 5-HT1BR densities. High doses of AZ10419369 exerted an extracranial tissue vasoconstriction that was comparable to the less blood-brain barrier-permeable 5-HT1BR agonist sumatriptan. By contrast, injection of the antagonist GR127935 did not elicit significant hemodynamic responses, even at a 5-HT1BR cerebral occupancy similar to the one obtained with a high dose of AZ10419369. Given the knowledge we have of the 5-HT1BR and its function and distribution in the brain, the hemodynamic response informs us about the functionality of the given drug: changes in CBV are only produced when the receptor is stimulated by the partial agonist AZ10419369 and not by the antagonist GR127935, consistent with low basal occupancy by endogenous serotonin.SIGNIFICANCE STATEMENT We here show that combined simultaneous positron emission tomography and magnetic resonance imaging uniquely enables the assessment of CNS active compounds. We conducted a series of pharmacological interventions to interrogate 5-HT1B receptor binding and function and determined blood-brain barrier passage of drugs and demonstrate target involvement. Importantly, we show how the spatial and temporal effects on brain hemodynamics provide information about pharmacologically driven downstream CNS drug effects; the brain hemodynamic response shows characteristic dose-related effects that differ depending on agonistic or antagonistic drug characteristics and on local 5-HT1B receptor density. The technique lends itself to a comprehensive in vivo investigation and understanding of drugs' effects in the brain.
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Lindberg A, Nag S, Schou M, Takano A, Matsumoto J, Amini N, Elmore CS, Farde L, Pike VW, Halldin C. [ 11C]AZ10419096 - a full antagonist PET radioligand for imaging brain 5-HT 1B receptors. Nucl Med Biol 2017; 54:34-40. [PMID: 28950161 DOI: 10.1016/j.nucmedbio.2017.07.007] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2017] [Revised: 06/05/2017] [Accepted: 07/14/2017] [Indexed: 10/19/2022]
Abstract
INTRODUCTION The serotonergic system is widely present in all regions of the central nervous system (CNS) and plays a key modulatory role in many of its functions. Positron emission tomography (PET) is used to study several serotonin receptors in CNS in vivo. The G-protein coupled receptor 5-HT1B is mostly present in the occipital cortex and in midbrain and is linked to several psychiatric disorders. There is evidence that agonist PET radioligands for neuroreceptors are more sensitive to endogenous neurotransmitters than antagonists. Our previously developed 5-HT1B receptor PET radioligand, [11C]AZ10419369, is now considered a partial agonist. In this work we are aiming to develop a full antagonist PET radioligand for imaging brain 5-HT1B receptors, and evaluate its sensitivity to increased endogenous serotonin concentration. MATERIALS [11C]AZ10419096 was synthesized by rapid methylation of the prepared corresponding N-desmethyl precursor with [11C]methyl triflate. Five PET measurements were performed in cynomolgus monkeys, consisting of two at baseline, one after treatment of a monkey with a 5-HT1B antagonist, AR-A000002, and two in which fenfluramine was administered during scanning to induce endogenous serotonin release. RESULTS AND DISCUSSION [11C]AZ10419096 was synthesized in high yield and purity within 30 min, including purification, formulation and sterile filtration. The baseline PET measurements demonstrated [11C]AZ10419096 to have favorable radioligand characteristics, including high specific binding in brain regions that have high 5-HT1B density, such as occipital cortex and globus pallidus, as well as subsequent rapid elimination from brain and a minor abundance of lipophilic radiometabolites in plasma. AR-A00002 completely blocked radioligand receptor-specific binding. Fenfluramine produced a distinct displacement of radioligand consistent with an expected increase of synaptic endogenous serotonin concentration. CONCLUSIONS [11C]AZ10419096, a full 5-HT1B antagonist PET radioligand, demonstrates high specific binding in monkey brain that is sensitive to competition from a known 5-HT1B antagonist as well as to putatively increased endogenous serotonin levels.
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Affiliation(s)
- Anton Lindberg
- Department of Clinical Neuroscience, Center for Psychiatry Research, Karolinska Institutet and Stockholm County Council, SE-171 76 Stockholm, Sweden.
| | - Sangram Nag
- Department of Clinical Neuroscience, Center for Psychiatry Research, Karolinska Institutet and Stockholm County Council, SE-171 76 Stockholm, Sweden
| | - Magnus Schou
- Department of Clinical Neuroscience, Center for Psychiatry Research, Karolinska Institutet and Stockholm County Council, SE-171 76 Stockholm, Sweden; AstraZeneca, Personalised Healthcare and Biomarkers, AstraZeneca PET Science Centre, Department of Clinical Neuroscience, Karolinska Institutet, Stockholm, Sweden
| | - Akihiro Takano
- Department of Clinical Neuroscience, Center for Psychiatry Research, Karolinska Institutet and Stockholm County Council, SE-171 76 Stockholm, Sweden
| | - Junya Matsumoto
- Department of Clinical Neuroscience, Center for Psychiatry Research, Karolinska Institutet and Stockholm County Council, SE-171 76 Stockholm, Sweden
| | - Nahid Amini
- Department of Clinical Neuroscience, Center for Psychiatry Research, Karolinska Institutet and Stockholm County Council, SE-171 76 Stockholm, Sweden
| | - Charles S Elmore
- Isotope chemistry, Early Chemical Development, Pharmaceutical Sciences Innovative Medicines and Early Development, AstraZeneca, Mölndal, Sweden
| | - Lars Farde
- Department of Clinical Neuroscience, Center for Psychiatry Research, Karolinska Institutet and Stockholm County Council, SE-171 76 Stockholm, Sweden; AstraZeneca, Personalised Healthcare and Biomarkers, AstraZeneca PET Science Centre, Department of Clinical Neuroscience, Karolinska Institutet, Stockholm, Sweden
| | - Victor W Pike
- Molecular Imaging Branch, National Institute of Mental Health, National Institutes of Health, Bethesda, Maryland 20892, USA
| | - Christer Halldin
- Department of Clinical Neuroscience, Center for Psychiatry Research, Karolinska Institutet and Stockholm County Council, SE-171 76 Stockholm, Sweden
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12
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Pittenger C, Adams TG, Gallezot JD, Crowley MJ, Nabulsi N, Ropchan J, Gao H, Kichuk SA, Simpson R, Billingslea E, Hannestad J, Bloch M, Mayes L, Bhagwagar Z, Carson RE. OCD is associated with an altered association between sensorimotor gating and cortical and subcortical 5-HT1b receptor binding. J Affect Disord 2016; 196:87-96. [PMID: 26919057 PMCID: PMC4808438 DOI: 10.1016/j.jad.2016.02.021] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/02/2015] [Revised: 12/02/2015] [Accepted: 02/07/2016] [Indexed: 01/04/2023]
Abstract
Obsessive-compulsive disorder (OCD) is characterized by impaired sensorimotor gating, as measured using prepulse inhibition (PPI). This effect may be related to abnormalities in the serotonin (5-HT) system. 5-HT1B agonists can impair PPI, produce OCD-like behaviors in animals, and exacerbate OCD symptoms in humans. We measured 5-HT1B receptor availability using (11)C-P943 positron emission tomography (PET) in unmedicated, non-depressed OCD patients (n=12) and matched healthy controls (HC; n=12). Usable PPI data were obtained from 20 of these subjects (10 from each group). There were no significant main effects of OCD diagnosis on 5-HT1B receptor availability ((11)C-P943 BPND); however, the relationship between PPI and (11)C-P943 BPND differed dramatically and significantly between groups. 5-HT1B receptor availability in the basal ganglia and thalamus correlated positively with PPI in controls; these correlations were lost or even reversed in the OCD group. In cortical regions there were no significant correlations with PPI in controls, but widespread positive correlations in OCD patients. Positive correlations between 5-HT1B receptor availability and PPI were consistent across diagnostic groups only in two structures, the orbitofrontal cortex and the amygdala. Differential associations of 5-HT1B receptor availability with PPI in patients suggest functionally important alterations in the serotonergic regulation of cortical/subcortical balance in OCD.
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Affiliation(s)
- Christopher Pittenger
- Department of Psychiatry, Yale University School of Medicine, USA; Department of Psychology, Yale University School of Medicine, USA; Child Study Center, Yale University School of Medicine, USA; Interdepartmental Neuroscience Program, Yale University School of Medicine, USA.
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Kumar JSD, Mann JJ. PET tracers for serotonin receptors and their applications. Cent Nerv Syst Agents Med Chem 2015; 14:96-112. [PMID: 25360773 DOI: 10.2174/1871524914666141030124316] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2014] [Revised: 10/26/2014] [Accepted: 10/28/2014] [Indexed: 11/22/2022]
Abstract
Serotonin receptors (5-HTRs) are implicated in the pathophysiology of a variety of neuropsychiatric and neurodegenerative disorders and are also targets for drug therapy. In the CNS, most of these receptors are expressed in high abundance in specific brain regions reflecting their role in brain functions. Quantifying binding to 5-HTRs in vivo may permit assessment of physiologic and pathologic conditions, and monitoring disease progression, evaluating treatment response, and for investigating new treatment modalities. Positron emission tomography (PET) molecular imaging has the sensitivity to quantify binding of 5-HTRs in CNS disorders and to measure drug occupancy as part of a process of new drug development. Although research on PET imaging of 5-HTRs have been performed more than two decades, the successful radiotracers so far developed for human studies are limited to 5-HT₁AR, 5-HT₁BR, 5-HT₂AR, 5-HT₄R and 5-HT₆R. Herein we review the development and application of radioligands for PET imaging of 5-HTRs in living brain.
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Affiliation(s)
| | - J John Mann
- Division of Molecular Imaging and Neuropathology, New York State Psychiatric institute, 1051 Riverside Drive, Box: 42, New York, NY, 10032, USA.
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14
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In vivo occupancy of the 5-HT1A receptor by a novel pan 5-HT1(A/B/D) receptor antagonist, GSK588045, using positron emission tomography. Neuropharmacology 2015; 92:44-8. [DOI: 10.1016/j.neuropharm.2014.11.017] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2014] [Revised: 10/27/2014] [Accepted: 11/25/2014] [Indexed: 02/05/2023]
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15
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Saricicek A, Chen J, Planeta B, Ruf B, Subramanyam K, Maloney K, Matuskey D, Labaree D, Deserno L, Neumeister A, Krystal JH, Gallezot JD, Huang Y, Carson RE, Bhagwagar Z. Test-retest reliability of the novel 5-HT1B receptor PET radioligand [11C]P943. Eur J Nucl Med Mol Imaging 2014; 42:468-77. [PMID: 25427881 DOI: 10.1007/s00259-014-2958-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2014] [Accepted: 11/03/2014] [Indexed: 10/24/2022]
Abstract
PURPOSE [(11)C]P943 is a novel, highly selective 5-HT1B PET radioligand. The aim of this study was to determine the test-retest reliability of [(11)C]P943 using two different modeling methods and to perform a power analysis with each quantification technique. METHODS Seven healthy volunteers underwent two PET scans on the same day. Regions of interest (ROIs) were the amygdala, hippocampus, pallidum, putamen, insula, frontal, anterior cingulate, parietal, temporal and occipital cortices, and cerebellum. Two multilinear radioligand quantification techniques were used to estimate binding potential: MA1, using arterial input function data, and the second version of the multilinear reference tissue model analysis (MRTM2), using the cerebellum as the reference region. Between-scan percent variability and intraclass correlation coefficients (ICC) were used to assess test-retest reliability. We also performed power analyses to determine the method that would allow the least number of subjects using within-subject or between-subject study designs. A voxel-wise ICC analysis for MRTM2 BPND was performed for the whole brain and all the ROIs studied. RESULTS Mean percent variability between two scans across regions ranged between 0.4 % and 12.4 % for MA1 BPND, 0.5 % and 11.5 % for MA1 BPP, 16.7 % and 28.3 % for MA1 BPF, and between 0.2 % and 5.4 % for MRTM2 BPND. The power analyses showed a greater number of subjects were required using MA1 BPF compared with other outcome measures for both within-subject and between-subject study designs. ICC values were the highest using MRTM2 BPND and the lowest with MA1 BPF in ten ROIs. Small regions and regions with low binding had lower ICC values than large regions and regions with high binding. CONCLUSION Reliable measures of 5-HT1B receptor binding can be obtained using the novel PET radioligand [(11)C]P943. Quantification of 5-HT1B receptor binding with MRTM2 BPND and with MA1 BPP provided the least variability and optimal power for within-subject and between-subject designs.
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16
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Zheng MQ, Kim SJ, Holden D, Lin SF, Need A, Rash K, Barth V, Mitch C, Navarro A, Kapinos M, Maloney K, Ropchan J, Carson RE, Huang Y. An Improved Antagonist Radiotracer for the κ-Opioid Receptor: Synthesis and Characterization of (11)C-LY2459989. J Nucl Med 2014; 55:1185-91. [PMID: 24854795 DOI: 10.2967/jnumed.114.138701] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2014] [Accepted: 03/25/2014] [Indexed: 11/16/2022] Open
Abstract
UNLABELLED The κ-opioid receptors (KORs) are implicated in several neuropsychiatric diseases and addictive disorders. PET with radioligands provides a means to image the KOR in vivo and investigate its function in health and disease. The purpose of this study was to develop the selective KOR antagonist (11)C-LY2459989 as a PET radioligand and characterize its imaging performance in nonhuman primates. METHODS LY2459989 was synthesized and assayed for in vitro binding to opioid receptors. Ex vivo studies in rodents were conducted to assess its potential as a tracer candidate. (11)C-LY2459989 was synthesized by reaction of its iodophenyl precursor with (11)C-cyanide, followed by partial hydrolysis of the resulting (11)C-cyanophenyl intermediate. Imaging experiments with (11)C-LY2459989 were performed in rhesus monkeys with arterial input function measurement. Imaging data were analyzed with kinetic models to derive in vivo binding parameters. RESULTS LY2459989 is a full antagonist with high binding affinity and selectivity for KOR (0.18, 7.68, and 91.3 nM, respectively, for κ, μ, and δ receptors). Ex vivo studies in rats indicated LY2459989 as an appropriate tracer candidate with high specific binding signals and confirmed its KOR binding selectivity in vivo. (11)C-LY2459989 was synthesized in high radiochemical purity and good specific activity. In rhesus monkeys, (11)C-LY2459989 displayed a fast rate of peripheral metabolism. Similarly, (11)C-LY2459989 displayed fast uptake kinetics in the brain and an uptake pattern consistent with the distribution of KOR in primates. Pretreatment with naloxone (1 mg/kg, intravenously) resulted in a uniform distribution of radioactivity in the brain. Further, specific binding of (11)C-LY2459989 was dose-dependently reduced by the selective KOR antagonist LY2456302 and the unlabeled LY2459989. Regional binding potential values derived from the multilinear analysis-1 (MA1) method, as a measure of in vivo specific binding signal, were 2.18, 1.39, 1.08, 1.04, 1.03, 0.59, 0.51, and 0.50, respectively, for the globus pallidus, cingulate cortex, insula, caudate, putamen, frontal cortex, temporal cortex, and thalamus. CONCLUSION The novel PET radioligand (11)C-LY2459989 displayed favorable pharmacokinetic properties, a specific and KOR-selective binding profile, and high specific binding signals in vivo, thus making it a promising PET imaging agent for KOR.
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Affiliation(s)
- Ming-Qiang Zheng
- PET Center, Department of Diagnostic Radiology, Yale University, New Haven, Connecticut; and
| | - Su Jin Kim
- PET Center, Department of Diagnostic Radiology, Yale University, New Haven, Connecticut; and
| | - Daniel Holden
- PET Center, Department of Diagnostic Radiology, Yale University, New Haven, Connecticut; and
| | - Shu-fei Lin
- PET Center, Department of Diagnostic Radiology, Yale University, New Haven, Connecticut; and
| | - Anne Need
- Eli Lilly & Company, Indianapolis, Indiana
| | - Karen Rash
- Eli Lilly & Company, Indianapolis, Indiana
| | | | | | | | - Michael Kapinos
- PET Center, Department of Diagnostic Radiology, Yale University, New Haven, Connecticut; and
| | - Kathleen Maloney
- PET Center, Department of Diagnostic Radiology, Yale University, New Haven, Connecticut; and
| | - Jim Ropchan
- PET Center, Department of Diagnostic Radiology, Yale University, New Haven, Connecticut; and
| | - Richard E Carson
- PET Center, Department of Diagnostic Radiology, Yale University, New Haven, Connecticut; and
| | - Yiyun Huang
- PET Center, Department of Diagnostic Radiology, Yale University, New Haven, Connecticut; and
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Kim SJ, Zheng MQ, Nabulsi N, Labaree D, Ropchan J, Najafzadeh S, Carson RE, Huang Y, Morris ED. Determination of the in vivo selectivity of a new κ-opioid receptor antagonist PET tracer 11C-LY2795050 in the rhesus monkey. J Nucl Med 2013; 54:1668-74. [PMID: 23918735 DOI: 10.2967/jnumed.112.118877] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
UNLABELLED (11)C-LY2795050 is a novel κ-selective antagonist PET tracer. The in vitro binding affinities (Ki) of LY2795050 at the κ-opioid (KOR) and μ-opioid (MOR) receptors are 0.72 and 25.8 nM, respectively. Thus, the in vitro KOR/MOR binding selectivity is about 36:1. Our goal in this study was to determine the in vivo selectivity of this new KOR antagonist tracer in the monkey. METHODS To estimate the ED50 value (dose of a compound [or drug] that gives 50% occupancy of the target receptor) of LY2795050 at the MOR and KOR sites, 2 series of blocking experiments were performed in 3 rhesus monkeys using (11)C-LY2795050 and (11)C-carfentanil with coinjections of various doses of unlabeled LY2795050. Kinetic modeling was applied to calculate regional binding potential (BP(ND)), and 1- and 2-site binding curves were fitted to these data to measure (11)C-LY2795050 binding selectivity. RESULTS The LY2795050 ED50 at MOR was 119 μg/kg based on a 1-site model for (11)C-carfentanil. The 1-site binding model was also deemed sufficient to describe the specific binding of (11)C-LY2795050 at KOR. The ED50 at KOR estimated from the 1-site model was 15.6 μg/kg. Thus, the ED50 ratio for MOR:KOR was 7.6. CONCLUSION The in vivo selectivity of (11)C-LY2795050 for KOR over MOR is 7.6. (11)C-LY2795050 has 4.7-fold-lower selectivity at KOR over MOR in vivo as compared with in vitro. Nevertheless, on the basis of our finding in vivo, 88% of the PET-observed specific binding of (11)C-LY2795050 under baseline conditions will be due to binding of the tracer at the KOR site in a region with similar prevalence of KOR and MOR. (11)C-LY2795050 is sufficiently selective for KOR over MOR in vivo to be considered an appropriate probe for studying the KOR with PET.
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Affiliation(s)
- Su Jin Kim
- Yale PET Center, Yale University, New Haven, Connecticut 06510, USA
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18
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Potenza MN, Walderhaug E, Henry S, Gallezot JD, Planeta-Wilson B, Ropchan J, Neumeister A. Serotonin 1B receptor imaging in pathological gambling. World J Biol Psychiatry 2013; 14:139-45. [PMID: 21936763 PMCID: PMC3595502 DOI: 10.3109/15622975.2011.598559] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Abstract Objectives. Although serotonergic mechanisms have been implicated in pathological gambling (PG), no ligand-based imaging studies have assessed serotonin receptors in individuals with PG. Given its role in substance addictions and its abundance in brain regions implicated in PG, we evaluated serotonin 1B receptors (5-HT1BRs) in PG. Methods. Ten medication-free subjects with PG (mean ± SD age = 36.3 ± 9.4 years, nine men) and ten control comparison (CC) subjects (mean ± SD age = 35.8 ± 9.9 years, nine men) underwent [(11)C]P943 positron emission scanning on a high resolution research tomograph. Results. 5-HT1BR BPND values were similar in PG and CC subjects (P > 0.1). Among PG subjects, scores on the South Oaks Gambling Screen (SOGS) correlated positively with 5-HT1BR BPND values in the ventral striatum (r = 0.66; P = 0.04), putamen (r = 0.67; P = 0.03) and anterior cingulate cortex (r = 0.73; P = 0.02). Conclusions. These findings provide the first evidence that PG severity in humans is linked to increased levels of 5-HT1BRs in regions previously implicated in functional neuroimaging studies of PG. These findings indicate a potential role for serotonergic function in the ventral striatum and anterior cingulate cortex contributing to problem gambling severity and warrant further studies to investigate whether numbers of available 5-HT1BRs might represent a vulnerability factor for PG or develop in relationship to problem gambling.
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Affiliation(s)
- Marc N. Potenza
- Department of Psychiatry, Yale University School of Medicine, New Haven, CT, USA,Department of Neurobiology, Yale University School of Medicine, New Haven, CT, USA,Department of Child Study Center Yale University School of Medicine, New Haven, CT, USA
| | - Espen Walderhaug
- Department of Psychiatry, Yale University School of Medicine, New Haven, CT, USA,Department of Addiction Treatment – Youth, Oslo University Hospital, Oslo, Norway
| | - Shannan Henry
- Department of Psychiatry, Yale University School of Medicine, New Haven, CT, USA,Department of Diagnostic Radiology, Yale University School of Medicine, New Haven, CT, USA
| | | | - Beata Planeta-Wilson
- Department of Diagnostic Radiology, Yale University School of Medicine, New Haven, CT, USA
| | - Jim Ropchan
- Department of Diagnostic Radiology, Yale University School of Medicine, New Haven, CT, USA
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Zheng MQ, Nabulsi N, Kim SJ, Tomasi G, Lin SF, Mitch C, Quimby S, Barth V, Rash K, Masters J, Navarro A, Seest E, Morris ED, Carson RE, Huang Y. Synthesis and evaluation of 11C-LY2795050 as a κ-opioid receptor antagonist radiotracer for PET imaging. J Nucl Med 2013; 54:455-63. [PMID: 23353688 DOI: 10.2967/jnumed.112.109512] [Citation(s) in RCA: 72] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
UNLABELLED Kappa-opioid receptors (KOR) are believed to be involved in the pathophysiology of depression, anxiety disorders, drug abuse, and alcoholism. To date, only 1 tracer, the KOR agonist (11)C-GR103545, has been reported to be able to image KOR in primates. The goal of the present study was to synthesize the selective KOR antagonist (11)C-LY2795050 and evaluate its potential as a PET tracer to image KOR in vivo. METHODS The in vitro binding affinity of LY2795050 was measured in radioligand competition binding assays. Ex vivo experiments were conducted using microdosing of the unlabeled ligand in Sprague-Dawley rats and in wild-type and KOR knockout mice, to assess the ligand's potential as a tracer candidate. Imaging experiments with (11)C-LY2795050 in monkeys were performed on the Focus-220 scanner with arterial blood input function measurement. Binding parameters were determined with kinetic modeling analysis. RESULTS LY2795050 displays full antagonist activity and high binding affinity and selectivity for KOR. Microdosing studies in rodents and ex vivo analysis of tissue concentrations with liquid chromatography-tandem mass spectrometry identified LY2795050 as an appropriate tracer candidate able to provide specific binding signals in vivo. (11)C-LY2795050 was prepared in an average yield of 12% and greater than 99% radiochemical purity. In rhesus monkeys, (11)C-LY2795050 displayed a moderate rate of peripheral metabolism, with approximately 40% of parent compound remaining at 30 min after injection. In the brain, (11)C-LY2795050 displayed fast uptake kinetics (regional activity peak times of <20 min) and an uptake pattern consistent with the distribution of KOR in primates. Pretreatment with naloxone (1 mg/kg, intravenously) resulted in a uniform distribution of radioactivity. Further, specific binding of (11)C-LY2795050 was reduced by the selective KOR antagonist LY2456302 in a dose-dependent manner. CONCLUSION (11)C-LY2795050 displayed favorable pharmacokinetic properties and binding profiles in vivo and therefore is a suitable ligand for imaging the KOR in primates. This newly developed KOR antagonist tracer has since been advanced to PET imaging of KOR in humans and constitutes the first successful KOR antagonist radiotracer.
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Affiliation(s)
- Ming-Qiang Zheng
- PET Center, Department of Diagnostic Radiology, Yale University, New Haven, Connecticut; and
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Smith DF, Jakobsen S. Molecular Neurobiology of Depression: PET Findings on the Elusive Correlation with Symptom Severity. Front Psychiatry 2013; 4:8. [PMID: 23459670 PMCID: PMC3586775 DOI: 10.3389/fpsyt.2013.00008] [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] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/01/2012] [Accepted: 02/11/2013] [Indexed: 01/08/2023] Open
Abstract
Molecular mechanisms in the brain are assumed to cause the symptoms and severity of neuropsychiatric disorders. This review concerns the elusive nature of relationships between the severity of depressive disorders and neuromolecular processes studied by positron emission tomography (PET). Recent PET studies of human depression have focused on serotonergic, dopaminergic, muscarinic, nicotinic, and GABAergic receptors, as well as central processes dependent on monoamine oxidase, phosphodiesterase type 4, amyloid plaques, neurofibrillar tangles, and P-glycoprotein. We find that reliable causal links between neuromolecular mechanisms and relief from depressive disorders have yet to be convincingly demonstrated. This situation may contribute to the currently limited use of PET for exploring the neuropathways that are currently viewed as being responsible for beneficial effects of antidepressant treatment regimes.
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Affiliation(s)
- Donald F Smith
- Center for Psychiatric Research, Psychiatric Hospital of Aarhus University Risskov, Denmark
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Savli M, Bauer A, Mitterhauser M, Ding YS, Hahn A, Kroll T, Neumeister A, Haeusler D, Ungersboeck J, Henry S, Isfahani SA, Rattay F, Wadsak W, Kasper S, Lanzenberger R. Normative database of the serotonergic system in healthy subjects using multi-tracer PET. Neuroimage 2012; 63:447-59. [PMID: 22789740 DOI: 10.1016/j.neuroimage.2012.07.001] [Citation(s) in RCA: 97] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2012] [Revised: 06/28/2012] [Accepted: 07/02/2012] [Indexed: 01/13/2023] Open
Abstract
The highly diverse serotonergic system with at least 16 different receptor subtypes is implicated in the pathophysiology of most neuropsychiatric disorders including affective and anxiety disorders, obsessive compulsive disorder, post-traumatic stress disorder, eating disorders, sleep disturbance, attention deficit/hyperactivity disorder, drug addiction, suicidal behavior, schizophrenia, Alzheimer, etc. Alterations of the interplay between various pre- and postsynaptic receptor subtypes might be involved in the pathogenesis of these disorders. However, there is a lack of comprehensive in vivo values using standardized procedures. In the current PET study we quantified 3 receptor subtypes, including the major inhibitory (5-HT(1A) and 5-HT(1B)) and excitatory (5-HT(2A)) receptors, and the transporter (5-HTT) in the brain of healthy human subjects to provide a database of standard values. PET scans were performed on 95 healthy subjects (age=28.0 ± 6.9 years; 59% males) using the selective radioligands [carbonyl-(11)C]WAY-100635, [(11)C]P943, [(18)F]altanserin and [(11)C]DASB, respectively. A standard template in MNI stereotactic space served for region of interest delineation. This template follows two anatomical parcellation schemes: 1) Brodmann areas including 41 regions and 2) AAL (automated anatomical labeling) including 52 regions. Standard values (mean, SD, and range) for each receptor and region are presented. Mean cortical and subcortical binding potential (BP) values were in good agreement with previously published human in vivo and post-mortem data. By means of linear equations, PET binding potentials were translated to post-mortem binding (provided in pmol/g), yielding 5.89 pmol/g (5-HT(1A)), 23.5 pmol/g (5-HT(1B)), 31.44 pmol/g (5-HT(2A)), and 11.33 pmol/g (5-HTT) being equivalent to the BP of 1, respectively. Furthermore, we computed individual voxel-wise maps with BP values and generated average tracer-specific whole-brain binding maps. This knowledge might improve our interpretation of the alterations taking place in the serotonergic system during neuropsychiatric disorders.
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Affiliation(s)
- Markus Savli
- Department of Psychiatry and Psychotherapy, Medical University of Vienna, Vienna, Austria
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Sandiego CM, Weinzimmer D, Carson RE. Optimization of PET-MR registrations for nonhuman primates using mutual information measures: a Multi-Transform Method (MTM). Neuroimage 2012; 64:571-81. [PMID: 22926293 DOI: 10.1016/j.neuroimage.2012.08.051] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2012] [Revised: 08/17/2012] [Accepted: 08/20/2012] [Indexed: 10/28/2022] Open
Abstract
An important step in PET brain kinetic analysis is the registration of functional data to an anatomical MR image. Typically, PET-MR registrations in nonhuman primate neuroreceptor studies used PET images acquired early post-injection, (e.g., 0-10 min) to closely resemble the subject's MR image. However, a substantial fraction of these registrations (~25%) fail due to the differences in kinetics and distribution for various radiotracer studies and conditions (e.g., blocking studies). The Multi-Transform Method (MTM) was developed to improve the success of registrations between PET and MR images. Two algorithms were evaluated, MTM-I and MTM-II. The approach involves creating multiple transformations by registering PET images of different time intervals, from a dynamic study, to a single reference (i.e., MR image) (MTM-I) or to multiple reference images (i.e., MR and PET images pre-registered to the MR) (MTM-II). Normalized mutual information was used to compute similarity between the transformed PET images and the reference image(s) to choose the optimal transformation. This final transformation is used to map the dynamic dataset into the animal's anatomical MR space, required for kinetic analysis. The chosen transforms from MTM-I and MTM-II were evaluated using visual rating scores to assess the quality of spatial alignment between the resliced PET and reference images. One hundred twenty PET datasets involving eleven different tracers from 3 different scanners were used to evaluate the MTM algorithms. Studies were performed with baboons and rhesus monkeys on the HR+, HRRT, and Focus-220. Successful transformations increased from 77.5%, 85.8%, to 96.7% using the 0-10 min method, MTM-I, and MTM-II, respectively, based on visual rating scores. The Multi-Transform Methods proved to be a robust technique for PET-MR registrations for a wide range of PET studies.
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Affiliation(s)
- Christine M Sandiego
- Department of Biomedical Engineering, Yale University, New Haven, CT 06520, USA.
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Matuskey D, Pittman B, Planeta-Wilson B, Walderhaug E, Henry S, Gallezot JD, Nabulsi N, Ding YS, Bhagwagar Z, Malison R, Carson RE, Neumeister A. Age effects on serotonin receptor 1B as assessed by PET. J Nucl Med 2012; 53:1411-4. [PMID: 22851636 DOI: 10.2967/jnumed.112.103598] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
UNLABELLED Previous imaging studies have suggested that there is an age-related decline in brain serotonin (5-hydroxytryptamine) measures in healthy subjects. This paper addresses whether the availability of 5-hydroxytryptamine receptor 1B (5-HT(1B)) is seen to decrease with aging via PET imaging. METHODS Forty-eight healthy control subjects (mean age ± SD, 30 ± 10 y; age range, 18-61 y; 33 men, 15 women) underwent (11)C-P943 scanning on a high-resolution PET tomograph. Regions were examined with and without gray matter masking, the latter in an attempt to control for age-related gray matter atrophy on nondisplaceable binding potential (BP(ND)) as determined by a validated multilinear reference tissue model. RESULTS 5-HT(1B) BP(ND) decreased in the cortex at an average rate of 8% per decade without and 9% with gray matter masking. A negative association with age was also observed in all individual cortical regions. Differences in the putamen and pallidum (positive association) were significant after adjustment for multiple comparisons. No sex- or race-related effects on 5-HT(1B) BP(ND) were found in any regions. CONCLUSION These findings indicate that age is a relevant factor for 5-HT(1B) in the cortex of healthy adults.
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Affiliation(s)
- David Matuskey
- Department of Psychiatry, Yale University School of Medicine, New Haven, Connecticut 06520, USA.
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Murrough JW, Czermak C, Henry S, Nabulsi N, Gallezot JD, Gueorguieva R, Planeta-Wilson B, Krystal JH, Neumaier JF, Huang Y, Ding YS, Carson RE, Neumeister A. The effect of early trauma exposure on serotonin type 1B receptor expression revealed by reduced selective radioligand binding. ACTA ACUST UNITED AC 2011; 68:892-900. [PMID: 21893657 DOI: 10.1001/archgenpsychiatry.2011.91] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
CONTEXT Serotonergic dysfunction is implicated in the pathogenesis of posttraumatic stress disorder (PTSD), and recent animal models suggest that disturbances in serotonin type 1B receptor function, in particular, may contribute to chronic anxiety. However, the specific role of the serotonin type 1B receptor has not been studied in patients with PTSD. OBJECTIVE To investigate in vivo serotonin type 1B receptor expression in individuals with PTSD, trauma-exposed control participants without PTSD (TC), and healthy (non-trauma-exposed) control participants (HC) using positron emission tomography and the recently developed serotonin type 1B receptor selective radiotracer [(11)C]P943. DESIGN Cross-sectional positron emission tomography study under resting conditions. SETTING Academic and Veterans Affairs medical centers. PARTICIPANTS Ninety-six individuals in 3 study groups: PTSD (n = 49), TC (n = 20), and HC (n = 27). Main Outcome Measure Regional [(11)C]P943 binding potential (BP(ND)) values in an a priori-defined limbic corticostriatal circuit investigated using multivariate analysis of variance and multiple regression analysis. RESULTS A history of severe trauma exposure in the PTSD and TC groups was associated with marked reductions in [(11)C]P943 BP(ND) in the caudate, the amygdala, and the anterior cingulate cortex. Participant age at first trauma exposure was strongly associated with low [(11)C]P943 BP(ND). Developmentally earlier trauma exposure also was associated with greater PTSD symptom severity and major depression comorbidity. CONCLUSIONS These data suggest an enduring effect of trauma history on brain function and the phenotype of PTSD. The association of early age at first trauma and more pronounced neurobiological and behavioral alterations in PTSD suggests a developmental component in the cause of PTSD.
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Affiliation(s)
- James W Murrough
- Mood and Anxiety Disorders Program, Department of Psychiatry, Mount Sinai School of Medicine, One Gustave L. Levy Place, New York, USA.
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Saulin A, Savli M, Lanzenberger R. Serotonin and molecular neuroimaging in humans using PET. Amino Acids 2011; 42:2039-57. [PMID: 21947614 DOI: 10.1007/s00726-011-1078-9] [Citation(s) in RCA: 67] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2011] [Accepted: 09/05/2011] [Indexed: 02/07/2023]
Abstract
The serotonergic system is one of the most important modulatory neurotransmitter systems in the human brain. It plays a central role in major physiological processes and is implicated in a number of psychiatric disorders. Along with the dopaminergic system, it is also one of the phylogenetically oldest human neurotransmitter systems and one of the most diverse, with 14 different receptors identified up to this day, many of whose function remains to be understood. The system's functioning is even more diverse than the number of its receptors, since each is implicated in a number of different processes. This review aims at illustrating the distribution and summarizing the main functions of the serotonin (5-hydroxytryptamin, 5-HT) receptors as well as the serotonin transporter (SERT, 5-HTT), the vesicular monoamine transporter 2, monoamine oxidase type A and 5-HT synthesis in the human brain. Recent advances in in vivo quantification of these different receptors and enzymes that are part of the serotonergic system using positron emission tomography are described.
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Affiliation(s)
- Anne Saulin
- Department of Psychiatry and Psychotherapy, Medical University of Vienna, Waehringer Guertel 18-20, 1090, Vienna, Austria
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Zhang M, Zhou D, Wang Y, Maier DL, Widzowski DV, Sobotka-Briner CD, Brockel BJ, Potts WM, Shenvi AB, Bernstein PR, Pierson ME. Preclinical pharmacology and pharmacokinetics of AZD3783, a selective 5-hydroxytryptamine 1B receptor antagonist. J Pharmacol Exp Ther 2011; 339:567-78. [PMID: 21825000 DOI: 10.1124/jpet.110.174433] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
The preclinical pharmacology and pharmacokinetic properties of (2R)-6-methoxy-8-(4-methylpiperazin-1-yl)-N-(4-morpholin-4-ylphenyl)chromane-2-carboxamide (AZD3783), a potent 5-hydroxytryptamine 1B (5-HT(1B)) receptor antagonist, were characterized as part of translational pharmacokinetic/pharmacodynamic hypothesis testing in human clinical trials. The affinity of AZD3783 to the 5-HT(1B) receptor was measured in vitro by using membrane preparations containing recombinant human or guinea pig 5-HT(1B) receptors and in native guinea pig brain tissue. In vivo antagonist potency of AZD3783 for the 5HT(1B) receptor was investigated by measuring the blockade of 5-HT(1B) agonist-induced guinea pig hypothermia. The anxiolytic-like potency was assessed using the suppression of separation-induced vocalization in guinea pig pups. The affinity of AZD3783 for human and guinea pig 5-HT(1B) receptor (K(i), 12.5 and 11.1 nM, respectively) was similar to unbound plasma EC(50) values for guinea pig receptor occupancy (11 nM) and reduction of agonist-induced hypothermia (18 nM) in guinea pig. Active doses of AZD3783 in the hypothermia assay were similar to doses that reduced separation-induced vocalization in guinea pig pups. AZD3783 demonstrated favorable pharmacokinetic properties. The predicted pharmacokinetic parameters (total plasma clearance, 6.5 ml/min/kg; steady-state volume of distribution, 6.4 l/kg) were within 2-fold of the values observed in healthy male volunteers after a single 20-mg oral dose. This investigation presents a direct link between AZD3783 in vitro affinity and in vivo receptor occupancy to preclinical disease model efficacy. Together with predicted human pharmacokinetic properties, we have provided a model for the quantitative translational pharmacology of AZD3783 that increases confidence in the optimal human receptor occupancy required for antidepressant and anxiolytic effects in patients.
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Affiliation(s)
- Minli Zhang
- Department of Drug Metabolism and Pharmacokinetics, AstraZeneca Pharmaceuticals, 35 Gatehouse Drive, Waltham, MA 02451, USA.
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Paterson LM, Kornum BR, Nutt DJ, Pike VW, Knudsen GM. 5-HT radioligands for human brain imaging with PET and SPECT. Med Res Rev 2011; 33:54-111. [PMID: 21674551 DOI: 10.1002/med.20245] [Citation(s) in RCA: 119] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
The serotonergic system plays a key modulatory role in the brain and is the target for many drug treatments for brain disorders either through reuptake blockade or via interactions at the 14 subtypes of 5-HT receptors. This review provides the history and current status of radioligands used for positron emission tomography (PET) and single photon emission computerized tomography (SPECT) imaging of human brain serotonin (5-HT) receptors, the 5-HT transporter (SERT), and 5-HT synthesis rate. Currently available radioligands for in vivo brain imaging of the 5-HT system in humans include antagonists for the 5-HT(1A), 5-HT(1B), 5-HT(2A), and 5-HT(4) receptors, and for SERT. Here we describe the evolution of these radioligands, along with the attempts made to develop radioligands for additional serotonergic targets. We describe the properties needed for a radioligand to become successful and the main caveats. The success of a PET or SPECT radioligand can ultimately be assessed by its frequency of use, its utility in humans, and the number of research sites using it relative to its invention date, and so these aspects are also covered. In conclusion, the development of PET and SPECT radioligands to image serotonergic targets is of high interest, and successful evaluation in humans is leading to invaluable insight into normal and abnormal brain function, emphasizing the need for continued development of both SPECT and PET radioligands for human brain imaging.
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Affiliation(s)
- Louise M Paterson
- Neuropsychopharmacology Unit, Division of Experimental Medicine, Imperial College London, Burlington Danes Building, Du Cane Road, London, United Kingdom
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Ridler K, Plisson C, Rabiner EA, Gunn RN, Easwaramoorthy B, Abi-Dargham A, Laruelle M, Slifstein M. Characterization of in vivo pharmacological properties and sensitivity to endogenous serotonin of [11C] P943: A positron emission tomography study in Papio anubis. Synapse 2011; 65:1119-27. [DOI: 10.1002/syn.20946] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2011] [Accepted: 04/21/2011] [Indexed: 11/08/2022]
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Cosgrove KP, Kloczynski T, Nabulsi N, Weinzimmer D, Lin SF, Staley JK, Bhagwagar Z, Carson RE. Assessing the sensitivity of [¹¹C]p943, a novel 5-HT1B radioligand, to endogenous serotonin release. Synapse 2011; 65:1113-7. [PMID: 21484884 DOI: 10.1002/syn.20942] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2011] [Accepted: 04/03/2011] [Indexed: 11/09/2022]
Abstract
The main objective of the current study was to determine the sensitivity of the positron emission tomography (PET) radioligand [¹¹C]P943 to fenfluramine-induced changes in endogenous 5-HT in nonhuman primate brain. Fenfluramine-induced changes in 5-HT(1B) occupancy were compared to those obtained by self-block with unlabeled P943. Two baboons and 1 rhesus monkey were given preblocking or displacing doses of fenfluramine (1-5 mg/kg) or preblocking doses of unlabeled P943 (0.2 mg/kg) and imaged with [¹¹C]P943 PET. Receptor occupancy by the low dose of fenfluramine (1 mg/kg) in the baboons was 25 and 29% and by the high dose of fenfluramine (5 mg/kg) in the rhesus macaque was 42%. Receptor occupancy by P943 (0.2 mg/kg) was 68 and 86% in the baboons. PET imaging of 5-HT(1B) receptors with [¹¹C]P943 may be a useful approach for measuring changes in endogenous 5-HT in the living human brain.
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Affiliation(s)
- Kelly P Cosgrove
- Department of Psychiatry, Yale University School of Medicine, New Haven, Connecticut, USA.
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Reduced ventral striatal/ventral pallidal serotonin1B receptor binding potential in major depressive disorder. Psychopharmacology (Berl) 2011; 213:547-53. [PMID: 20480149 PMCID: PMC3139174 DOI: 10.1007/s00213-010-1881-0] [Citation(s) in RCA: 89] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/18/2010] [Accepted: 05/04/2010] [Indexed: 01/19/2023]
Abstract
RATIONALE Although serotonin (5-HT) dysregulation is implicated in the pathophysiology of major depressive disorder (MDD), the role of specific receptor subtypes remains to be elucidated. Emerging preclinical research suggests an important role for the 5-HT(1B) receptor in behavioral regulation and depressive phenotypes. In particular, 5-HT(1B) heteroreceptors located within the striatum have been shown to play an essential role in antidepressant action. OBJECTIVES The objective of this study was to determine 5-HT(1B) receptor binding potential (BP (ND)) in the region of the ventral striatum/ventral pallidum (VS/VP) in individuals with MDD and healthy control participants. METHODS Ten participants with MDD (30.8 ± 9.5 years, five men/five women) in a current major depressive episode (MDE) and ten healthy control participants (30.7 ± 10.5 years, five men/five women) underwent positron emission tomography (PET) scanning with the selective 5-HT(1B) receptor radioligand [(11)C]P943. RESULTS Within the VS/VP region of interest, [(11)C]P943 BP (ND) was significantly reduced in the MDD group compared with the healthy control group (1.37 ± 0.13 and 1.68 ± 0.16, respectively; 18.7% between-group difference; p < 0.001). CONCLUSIONS Consistent with preclinical and postmortem data, our findings suggest abnormally reduced function of VS/VP 5-HT(1B) receptors in humans with MDD. Abnormal 5-HT(1B) heteroreceptor function may contribute to dysfunctional reward signaling within the striatum, including the nucleus accumbens, via interaction with dopamine, γ-amino-butyric acid, or glutamate systems. Our findings suggest reduced 5-HT(1B) receptor signaling in the VS/VP in MDD and contribute to the therapeutic rationale for testing 5-HT(1B) agonists as a novel class of antidepressants.
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Nabulsi NB, Zheng MQ, Ropchan J, Labaree D, Ding YS, Blumberg L, Huang Y. [11C]GR103545: novel one-pot radiosynthesis with high specific activity. Nucl Med Biol 2010; 38:215-21. [PMID: 21315277 DOI: 10.1016/j.nucmedbio.2010.08.014] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2010] [Revised: 08/03/2010] [Accepted: 08/27/2010] [Indexed: 10/18/2022]
Abstract
INTRODUCTION GR103545 is a potent and selective kappa-opioid receptor agonist. Previous studies in non-human primates demonstrated favorable properties of [(11)C]GR103545 as a positron emission tomography tracer for in vivo imaging of cerebral kappa-opioid receptor. Nonetheless, advancement of [(11)C]GR103545 to imaging studies in humans was hampered by difficulties of its multiple-step radiosynthesis, which produces a final product with low specific activity (SA), which in turn could induce undesirable physiological side effects resulting from the mass associated with an injected amount of radioactivity. We report herein an alternative radiosynthesis of [(11)C]GR103545 with higher SA and radiochemical yields. METHODS The TRACERLab FXC automated synthesis module was used to carry out the two-step, one-pot procedure. In the first step, the desmethoxycarbonyl precursor was converted to the carbamic acid intermediate desmethyl-GR103545 via transcarboxylation with the zwitterionic carbamic complex, 1,8-diazabicyclo[5.4.0]undec-7-ene-carbon dioxide, in the presence and/or absence of cesium carbonate and tetrabutylammonium triflate. In the second step, the intermediate was radiolabeled at the carboxyl oxygen with [(11)C]methyl trifluoromethanesulfonate to give [(11)C]GR103545. RESULTS This novel synthesis produced [(11)C]GR103545 with ≥90% chemical and radiochemical purities and an SA of 290.45±99.9 MBq/nmol at the end of synthesis (n=26). Injectable radioactivity was 1961±814 GBq/μmol with 43 min of average synthesis time from the end of beam. CONCLUSION We have developed a practical one-pot method for the routine production of [(11)C]GR103545 with reliably high SA and radiochemical yield, thus allowing the advancement of this radiotracer to imaging applications in humans.
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Affiliation(s)
- Nabeel B Nabulsi
- Department of Diagnostic Radiology, PET Center, Yale School of Medicine, PO Box 208048, New Haven, CT 06520-8048, USA.
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Abstract
Molecular in vivo neuroimaging techniques can be used to measure regional changes in endogenous neurotransmitters, evoked by challenges that alter synaptic neurotransmitter concentration. This technique has most successfully been applied to the study of endogenous dopamine release using positron emission tomography, but has not yet been adequately extended to other neurotransmitter systems. This review focuses on how the technique has been applied to the study of the 5-hydroxytryptamine (5-HT) system. The principles behind visualising fluctuations in neurotransmitters are introduced, with reference to the dopaminergic system. Studies that aim to image acute, endogenous 5-HT release or depletion at 5-HT receptor targets are summarised, with particular attention to studies in humans. Radiotracers targeting the 5-HT(1A), 5-HT(2A), and 5-HT(4) receptors and the serotonin reuptake transporter have been explored for their sensitivity to 5-HT fluctuations, but with mixed outcomes; tracers for these targets cannot reliably image endogenous 5-HT in humans. Shortcomings in our basic knowledge of the mechanisms underlying changes in binding potential are addressed, and suggestions are made as to how the selection of targets, radiotracers, challenge paradigms, and experimental design might be optimised to improve our chances of successfully imaging endogenous neurotransmitters in the future.
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Gallezot JD, Weinzimmer D, Nabulsi N, Lin SF, Fowles K, Sandiego C, McCarthy TJ, Maguire RP, Carson RE, Ding YS. Evaluation of [(11)C]MRB for assessment of occupancy of norepinephrine transporters: Studies with atomoxetine in non-human primates. Neuroimage 2010; 56:268-79. [PMID: 20869448 DOI: 10.1016/j.neuroimage.2010.09.040] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2010] [Accepted: 09/16/2010] [Indexed: 12/15/2022] Open
Abstract
[(11)C]MRB is one of the most promising radioligands used to measure brain norepinephrine transporters (NET) with positron emission tomography (PET). The objective of this study was to evaluate the suitability of [(11)C]MRB for drug occupancy studies of NET using atomoxetine (ATX), a NET uptake inhibitor used in the treatment of depression and attention-deficit hyperactivity disorder (ADHD). A second goal of the study was identification of a suitable reference region. Ten PET studies were performed in three anesthetized rhesus monkeys following an infusion of ATX or placebo. [(11)C]MRB arterial input functions and ATX plasma levels were also measured. A dose-dependent reduction of [(11)C]MRB volume of distribution was observed after correction for [(11)C]MRB plasma free fraction. ATX IC(50) was estimated to be 31 ± 10ng/mL plasma. This corresponds to an effective dose (ED(50)) of 0.13mg/kg, which is much lower than the therapeutic dose of ATX in ADHD (1.0-1.5mg/kg). [(11)C]MRB binding potential BP(ND) in the thalamus was estimated to be 1.8 ± 0.3. Defining a reference region for a NET radiotracer is challenging due to the widespread and relatively uniform distribution of NET in the brain. Three regions were evaluated for use as reference region: caudate, putamen and occipital cortex. Caudate was found to be the most suitable for preclinical drug occupancy studies in rhesus monkeys. The IC(50) estimate obtained using MRTM2 BP(ND) without arterial blood sampling was 21 ± 3ng/mL (using caudate as the reference region). This study demonstrated that [(11)C]MRB is suitable for drug occupancy studies of NET.
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Serotonin 1B receptor imaging in alcohol dependence. Biol Psychiatry 2010; 67:800-3. [PMID: 20172504 PMCID: PMC3112181 DOI: 10.1016/j.biopsych.2009.12.028] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/16/2009] [Revised: 12/18/2009] [Accepted: 12/22/2009] [Indexed: 11/23/2022]
Abstract
BACKGROUND Although animal models suggest that alcohol dependence (AD) is associated with elevations in the number of serotonin 1B receptors (5-HT(1B)R), 5-HT(1B)R levels have not been investigated in people with AD. The selective 5-HT(1B)R antagonist radioligand, [(11)C]P943, permits in vivo assessment of central 5-HT(1B)R binding potential (BP(ND)) with positron emission tomography. Because of its central role in AD, we were particularly interested in ventral striatal 5-HT(1B)R BP(ND) values. METHODS Twelve medication-free, recently abstinent (at least 4 weeks) patients with AD (mean age 35.2 +/- 10.2 years, 5 women) and 12 healthy control subjects (HC) (mean age 30.6 +/- 9.2 years, 5 women) completed [(11)C]P943 positron emission tomography on a high-resolution research tomograph. Individual magnetic resonance imaging scans were collected to exclude individuals with anatomical abnormalities and for coregistration. Imaging data were analyzed with a multilinear reference tissue model. RESULTS Ventral striatal 5-HT(1B)R BP(ND) values (2.01 +/- .57% and 1.55 +/- .09%, respectively; 29% between-group difference, p = .006) were increased in AD compared with HC subjects. No influence of demographic or clinical variables or amount of injected radiotracer was observed. CONCLUSIONS This study provides the first evidence that AD in humans is, like in rodent models, associated with increased levels of ventral striatal 5-HT(1B)Rs.
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