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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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Colom M, Vidal B, Fieux S, Redoute J, Costes N, Lavenne F, Mérida I, Irace Z, Iecker T, Bouillot C, Billard T, Newman-Tancredi A, Zimmer L. [ 18F]F13640, a 5-HT 1A Receptor Radiopharmaceutical Sensitive to Brain Serotonin Fluctuations. Front Neurosci 2021; 15:622423. [PMID: 33762906 PMCID: PMC7982540 DOI: 10.3389/fnins.2021.622423] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2020] [Accepted: 02/17/2021] [Indexed: 12/30/2022] Open
Abstract
Introduction Serotonin is involved in a variety of physiological functions and brain disorders. In this context, efforts have been made to investigate the in vivo fluctuations of this neurotransmitter using positron emission tomography (PET) imaging paradigms. Since serotonin is a full agonist, it binds preferentially to G-protein coupled receptors. In contrast, antagonist PET ligands additionally interact with uncoupled receptors. This could explain the lack of sensitivity to serotonin fluctuations of current 5-HT1A radiopharmaceuticals which are mainly antagonists and suggests that agonist radiotracers would be more appropriate to measure changes in neurotransmitter release. The present study evaluated the sensitivity to endogenous serotonin release of a recently developed, selective 5-HT1A receptor PET radiopharmaceutical, the agonist [18F]F13640 (a.k.a. befiradol or NLX-112). Materials and Methods Four cats each underwent three PET scans with [18F]F13640, i.e., a control PET scan of 90 min, a PET scan preceded 30 min before by an intravenous injection 1 mg/kg of d-fenfluramine, a serotonin releaser (blocking challenge), and a PET scan comprising the intravenous injection of 1 mg/kg of d-fenfluramine 30 min after the radiotracer injection (displacement challenge). Data were analyzed with regions of interest and voxel-based approaches. A lp-ntPET model approach was implemented to determine the dynamic of serotonin release during the challenge study. Results D-fenfluramine pretreatment elicited a massive inhibition of [18F]F13640 labeling in regions known to express 5-HT1A receptors, e.g., raphe nuclei, hippocampus, thalamus, anterior cingulate cortex, caudate putamen, occipital, frontal and parietal cortices, and gray matter of cerebellum. Administration of d-fenfluramine during PET acquisition indicates changes in occupancy from 10% (thalamus) to 31% (gray matter of cerebellum) even though the dissociation rate of [18F]F13640 over the 90 min acquisition time was modest. The lp-ntPET simulation succeeded in differentiating the control and challenge conditions. Conclusion The present findings demonstrate that labeling of 5-HT1A receptors with [18F]F13640 is sensitive to serotonin concentration fluctuations in vivo. Although the data underline the need to perform longer PET scan to ensure accurate measure of displacement, they support clinical development of [18F]F13640 as a tool to explore experimental paradigms involving physiological or pathological (neurological or neuropsychiatric pathologies) fluctuations of extracellular serotonin.
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Affiliation(s)
- Matthieu Colom
- Lyon Neuroscience Research Center, INSERM, CNRS, Université de Lyon, Université Claude Bernard Lyon 1, Lyon, France.,Hospices Civils de Lyon, Lyon, France
| | - Benjamin Vidal
- Lyon Neuroscience Research Center, INSERM, CNRS, Université de Lyon, Université Claude Bernard Lyon 1, Lyon, France
| | - Sylvain Fieux
- Lyon Neuroscience Research Center, INSERM, CNRS, Université de Lyon, Université Claude Bernard Lyon 1, Lyon, France
| | | | | | | | | | | | | | | | | | | | - Luc Zimmer
- Lyon Neuroscience Research Center, INSERM, CNRS, Université de Lyon, Université Claude Bernard Lyon 1, Lyon, France.,Hospices Civils de Lyon, Lyon, France.,CERMEP-Imagerie du Vivant, Bron, France.,Institut National des Sciences et Techniques Nucléaires, Gif-sur-Yvette, France
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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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4
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Girgis RR, Forbes A, Abi-Dargham A, Slifstein M. A positron emission tomography occupancy study of brexpiprazole at dopamine D 2 and D 3 and serotonin 5-HT 1A and 5-HT 2A receptors, and serotonin reuptake transporters in subjects with schizophrenia. Neuropsychopharmacology 2020; 45:786-792. [PMID: 31847007 PMCID: PMC7075883 DOI: 10.1038/s41386-019-0590-6] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/15/2019] [Revised: 11/20/2019] [Accepted: 12/05/2019] [Indexed: 11/09/2022]
Abstract
The objective of this study (NCT01854944) was to assess D2/D3, 5-HT1A, 5-HT2A and serotonin transporter (SERT) occupancies of brexpiprazole in adult subjects with schizophrenia in order to identify the in vivo pharmacologic profile that may be relevant to the antipsychotic, antidepressant, and side effect profiles of the drug. Subjects were grouped into three independent cohorts of four subjects each. All subjects underwent positron emission tomography (PET) scans with two different radiotracers at baseline prior to brexpiprazole administration, and again on Day 10 after daily doses of either 4 mg (Cohorts 1 and 2), or 1 mg (Cohort 3). Cohort 1 received scans with [11C]-(+)-PHNO to measure D2 and D3 receptor occupancy and [11C]CUMI101 to measure 5-HT1A occupancy; Cohort 2 received [11C]MDL100907 for 5-HT2A occupancy and [11C]DASB for SERT occupancy; Cohort 3 underwent scanning with [11C]-(+)-PHNO and [11C]MDL100907. Five female and seven male subjects, aged 42 ± 8 years (range, 28-55 years), participated in this study. Dose dependency was observed at D2 receptors, with occupancies reaching 64 ± 8% (mean +/- SD) following 1 mg/day and 80 ± 12% following 4 mg/day. D3 receptor availability increased following 1 mg brexpiprazole treatment and did not change with 4 mg. Robust and dose-related occupancy was also observed at 5-HT2A receptors. Negligible occupancy (<5%) was observed at 5-HT1A and SERT at 4 mg/day. In summary, brexpiprazole demonstrated in vivo binding to D2 receptors and 5-HT2A receptors at steady state after 10 days of daily administration in a dose dependent manner, while binding to D3, 5-HT1A receptors and SERT was not detectable with the radiotracers used for these targets. This pharmacologic profile is consistent with the observed antipsychotic and antidepressant effects.
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Affiliation(s)
- Ragy R Girgis
- New York State Psychiatric Institute, Columbia University Irving Medical Center, New York, NY, USA.
| | - Andy Forbes
- Otsuka Pharmaceutical Development & Commercialization Inc., Princeton, NJ, USA
| | - Anissa Abi-Dargham
- Department of Psychiatry, Renaissance School of Medicine, Stony Brook University, Stony Brook, NY, USA
| | - Mark Slifstein
- Department of Psychiatry, Renaissance School of Medicine, Stony Brook University, Stony Brook, NY, USA
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5
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Measuring endogenous changes in serotonergic neurotransmission with [ 11C]Cimbi-36 positron emission tomography in humans. Transl Psychiatry 2019; 9:134. [PMID: 30975977 PMCID: PMC6459901 DOI: 10.1038/s41398-019-0468-8] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/05/2019] [Accepted: 03/24/2019] [Indexed: 12/28/2022] Open
Abstract
Developing positron emission tomography (PET) radioligands for the detection of endogenous serotonin release will enable the investigation of serotonergic deficits in many neuropsychiatric disorders. The present study investigates how acute challenges that aim to increase or decrease cerebral serotonin levels affect binding of the serotonin 2A receptor (5-HT2AR) agonist radioligand [11C]Cimbi-36. In a randomized, double-blind, placebo-controlled, three-arm design, 23 healthy volunteers were PET scanned twice with [11C]Cimbi-36: at baseline and following double-blind assignment to one of three interventions (1) infusion of the selective serotonin reuptake inhibitor (SSRI) citalopram preceded by oral dosing of the 5-HT1AR antagonist pindolol, (n = 8) (2) acute tryptophan depletion (ATD) (n = 7) and (3) placebo (n = 8). Two-sample t-tests revealed no significant group differences in percent change of neocortical [11C]Cimbi-36 binding from baseline to intervention between placebo and citalopram/pindolol (p = 0.4) or between placebo and ATD (p = 0.5). Notably, there was a significantly larger within-group variation in 5-HT2AR binding after intervention with citalopram/pindolol, as compared with placebo (p = 0.007). These findings suggest that neither ATD nor a combination of citalopram and pindolol elicit acute unidirectional changes in serotonin levels sufficient to be detected with [11C]Cimbi-36 PET in neocortex. We suggest that the large interindividual variation in 5-HT2AR binding after citalopram/pindolol reflects that after an acute SSRI intervention, individuals respond substantially different in terms of their brain serotonin levels. Our observation has a potential impact for the understanding of patient responses to SSRI.
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6
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Shalgunov V, van Waarde A, Booij J, Michel MC, Dierckx RAJO, Elsinga PH. Hunting for the high-affinity state of G-protein-coupled receptors with agonist tracers: Theoretical and practical considerations for positron emission tomography imaging. Med Res Rev 2018; 39:1014-1052. [PMID: 30450619 PMCID: PMC6587759 DOI: 10.1002/med.21552] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2018] [Revised: 10/02/2018] [Accepted: 10/19/2018] [Indexed: 12/15/2022]
Abstract
The concept of the high‐affinity state postulates that a certain subset of G‐protein‐coupled receptors is primarily responsible for receptor signaling in the living brain. Assessing the abundance of this subset is thus potentially highly relevant for studies concerning the responses of neurotransmission to pharmacological or physiological stimuli and the dysregulation of neurotransmission in neurological or psychiatric disorders. The high‐affinity state is preferentially recognized by agonists in vitro. For this reason, agonist tracers have been developed as tools for the noninvasive imaging of the high‐affinity state with positron emission tomography (PET). This review provides an overview of agonist tracers that have been developed for PET imaging of the brain, and the experimental paradigms that have been developed for the estimation of the relative abundance of receptors configured in the high‐affinity state. Agonist tracers appear to be more sensitive to endogenous neurotransmitter challenge than antagonists, as was originally expected. However, other expectations regarding agonist tracers have not been fulfilled. Potential reasons for difficulties in detecting the high‐affinity state in vivo are discussed.
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Affiliation(s)
- Vladimir Shalgunov
- Department of Nuclear Medicine and Molecular Imaging, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - Aren van Waarde
- Department of Nuclear Medicine and Molecular Imaging, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - Jan Booij
- Department of Radiology and Nuclear Medicine, Amsterdam University Medical Centers, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Martin C Michel
- Department of Pharmacology, Johannes Gutenberg University, Mainz, Germany
| | - Rudi A J O Dierckx
- Department of Nuclear Medicine and Molecular Imaging, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands.,Department of Nuclear Medicine, Ghent University, University Hospital, Ghent, Belgium
| | - Philip H Elsinga
- Department of Nuclear Medicine and Molecular Imaging, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
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7
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Yang KC, Takano A, Halldin C, Farde L, Finnema SJ. Serotonin concentration enhancers at clinically relevant doses reduce [ 11C]AZ10419369 binding to the 5-HT 1B receptors in the nonhuman primate brain. Transl Psychiatry 2018; 8:132. [PMID: 30013068 PMCID: PMC6048172 DOI: 10.1038/s41398-018-0178-7] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/26/2017] [Revised: 02/14/2018] [Accepted: 04/03/2018] [Indexed: 12/25/2022] Open
Abstract
The serotonin (5-HT) system plays an important role in the pathophysiology and treatment of several major psychiatric disorders. Currently, no suitable positron emission tomography (PET) imaging paradigm is available to assess 5-HT release in the living human brain. [11C]AZ10419369 binds to 5-HT1B receptors and is one of the most 5-HT-sensitive radioligands available. This study applied 5-HT concentration enhancers which can be safely studied in humans, and examined their effect on [11C]AZ10419369 binding at clinically relevant doses, including amphetamine (1 mg/kg), 3,4-methylenedioxymethamphetamine (MDMA; 1 mg/kg) or 5-hydroxy-L-tryptophan (5-HTP; 5 mg/kg). Twenty-six PET measurements (14 for amphetamine, 6 for MDMA and 6 for 5-HTP) using a bolus and constant infusion protocol were performed in four cynomolgus monkeys before or after drug administration. Binding potential (BPND) values were determined with the equilibrium method (integral interval: 63-123 min) using cerebellum as the reference region. BPND values were significantly decreased in several examined brain regions after administration of amphetamine (range: 19-31%), MDMA (16-25%) or 5-HTP (13-31%). Reductions in [11C]AZ10419369 binding were greater in striatum than cortical regions after administration of 5-HTP, while no prominent regional differences were found for amphetamine and MDMA. In conclusion, [11C]AZ10419369 binding is sensitive to changes in 5-HT concentration induced by amphetamine, MDMA or 5-HTP. The robust changes in BPND, following pretreatment drugs administered at clinically relevant doses, indicate that the applied PET imaging paradigms hold promise to be successfully used in future human studies.
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Affiliation(s)
- Kai-Chun Yang
- Department of Clinical Neuroscience, Center for Psychiatric Research, Karolinska Institutet, Karolinska University Hospital, Stockholm, Sweden.
| | - Akihiro Takano
- Department of Clinical Neuroscience, Center for Psychiatric Research, Karolinska Institutet, Karolinska University Hospital, Stockholm, Sweden
| | - Christer Halldin
- Department of Clinical Neuroscience, Center for Psychiatric Research, Karolinska Institutet, Karolinska University Hospital, Stockholm, Sweden
| | - Lars Farde
- Department of Clinical Neuroscience, Center for Psychiatric Research, Karolinska Institutet, Karolinska University Hospital, Stockholm, Sweden
- Personalized Health Care and Biomarkers, AstraZeneca PET Science Center at Karolinska Institutet, Stockholm, Sweden
| | - Sjoerd J Finnema
- Department of Clinical Neuroscience, Center for Psychiatric Research, Karolinska Institutet, Karolinska University Hospital, Stockholm, Sweden
- Department of Radiology and Biomedical Imaging, Yale University, New Haven, CT, USA
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8
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Jørgensen LM, Weikop P, Svarer C, Feng L, Keller SH, Knudsen GM. Cerebral serotonin release correlates with [ 11C]AZ10419369 PET measures of 5-HT 1B receptor binding in the pig brain. J Cereb Blood Flow Metab 2018; 38:1243-1252. [PMID: 28685616 PMCID: PMC6434452 DOI: 10.1177/0271678x17719390] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/01/2017] [Revised: 04/26/2017] [Accepted: 05/21/2017] [Indexed: 11/17/2022]
Abstract
Positron emission tomography (PET) can, when used with appropriate radioligands, non-invasively capture temporal and spatial information about acute changes in brain neurotransmitter systems. We here evaluate the 5-HT1B receptor partial agonist PET radioligand, [11C]AZ10419369, for its sensitivity to detect changes in endogenous cerebral serotonin levels, as induced by different pharmacological challenges. To enable a direct translation of PET imaging data to changes in brain serotonin levels, we compared the [11C]AZ10419369 PET signal in the pig brain to simultaneous measurements of extracellular serotonin levels with microdialysis after various acute interventions (saline, escitalopram, fenfluramine). The interventions increased the cerebral extracellular serotonin levels to two to six times baseline, with fenfluramine being the most potent pharmacological enhancer of serotonin release. The interventions induced a varying degree of decline in [11C]AZ10419369 binding in the brain, consistent with the occupancy competition model. The observed correlation between changes in the extracellular serotonin level in the pig brain and the 5-HT1B receptor occupancy indicates that [11C]AZ10419369 binding is sensitive to changes in endogenous serotonin levels to a degree equivalent to that reported of [11C]raclopride to dopamine, a much used approach to detect in vivo change in cerebral dopamine.
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Affiliation(s)
- Louise M Jørgensen
- Neurobiology Research Unit,
Rigshospitalet, Copenhagen, Denmark
- Faculty of Health and Medical Sciences,
University of Copenhagen, Copenhagen, Denmark
| | - Pia Weikop
- Department of Neuroscience and
Pharmacology, The Laboratory of Neuropsychiatry, University of Copenhagen,
Copenhagen, Denmark
- Psychiatric Centre Copenhagen,
University of Copenhagen, Copenhagen, Denmark
| | - Claus Svarer
- Neurobiology Research Unit,
Rigshospitalet, Copenhagen, Denmark
| | - Ling Feng
- Neurobiology Research Unit,
Rigshospitalet, Copenhagen, Denmark
| | - Sune H Keller
- Department of Clinical Physiology,
Nuclear Medicine and PET, Rigshospitalet, University of Copenhagen, Copenhagen,
Denmark
| | - Gitte M Knudsen
- Neurobiology Research Unit,
Rigshospitalet, Copenhagen, Denmark
- Faculty of Health and Medical Sciences,
University of Copenhagen, Copenhagen, Denmark
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18F-F13640 preclinical evaluation in rodent, cat and primate as a 5-HT 1A receptor agonist for PET neuroimaging. Brain Struct Funct 2018; 223:2973-2988. [PMID: 29730825 DOI: 10.1007/s00429-018-1672-7] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2017] [Accepted: 04/20/2018] [Indexed: 12/23/2022]
Abstract
Serotonin 1A receptors are known to play an important role in many psychiatric and neurodegenerative disorders. Currently, all available 5-HT1A receptor PET radiopharmaceuticals that are radiolabeled with fluorine-18 are antagonists. As agonists bind preferentially to the high-affinity state of receptors, it would be of great interest to develop agonist radioligands which could provide a measure of the functional 5-HT1A receptors in pathophysiological processes. The 5-HT1A receptor agonist candidates we recently proposed had promising in vitro properties but were not optimal in terms of PET imaging. F13640, a.k.a befiradol or NLX-112, is a 5-HT1A receptor agonist with a high affinity (Ki = 1 nM) and a high selectivity that would be suitable for a potential PET radiopharmaceutical. With propose here the first preclinical evaluation of 18F-F13640. 18F-F13640's nitro-precursor was synthesized and radiolabeled via a fluoro-nucleophilic substitution. Its radiopharmacological characterization included autoradiographic studies, metabolic studies, and in vivo PET scans in rat, cat and non-human primate. Some of the results were compared with the radiotracer 18F-MPPF, a 5-HT1A receptor antagonist. The radiochemical purity of 18F-F13640 was > 98%. In vitro binding pattern was consistent with the 5-HT1A receptor distribution. Metabolic studies revealed that the radiotracer rapidly entered the brain and led to few brain radiometabolites. Although 18F-F13640 in vivo binding was blocked by the 5-HT1A antagonist WAY-100635 and the 5-HT1A agonist 8-OH-DPAT, the distribution pattern was markedly different from antagonist radiotracers in the three species, suggesting it provides novel information on 5-HT1A receptors. Preliminary studies also suggest a high sensitivity of 18F-F13640 to endogenous serotonin release. 18F-F13640 has suitable characteristics for probing in vitro and in vivo the 5-HT1A receptors in high-affinity state. Quantification analyses with kinetic modeling are in progress to prepare the first-in-man study of 18F-F13640.
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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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11
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Ganz M, Feng L, Hansen HD, Beliveau V, Svarer C, Knudsen GM, Greve DN. Cerebellar heterogeneity and its impact on PET data quantification of 5-HT receptor radioligands. J Cereb Blood Flow Metab 2017; 37:3243-3252. [PMID: 28075185 PMCID: PMC5584698 DOI: 10.1177/0271678x16686092] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/14/2016] [Revised: 11/18/2016] [Accepted: 11/22/2016] [Indexed: 11/15/2022]
Abstract
In the quantification of positron emission tomography (PET) radiotracer binding, a commonly used method is reference tissue modeling (RTM). RTM necessitates a proper reference and a ubiquitous choice for G-protein coupled receptors is the cerebellum. We investigated regional differences in uptake within the grey matter of the cerebellar hemispheres (CH), the cerebellar white matter (CW), and the cerebellar vermis (CV) for five PET radioligands targeting the serotonin system. Furthermore, we evaluated the impact of choosing different reference regions when quantifying neocortical binding. The PET and MR images are part of the Cimbi database: 5-HT1AR ([11C]CUMI-101, n = 8), 5-HT1BR ([11C]AZ10419369, n = 36), 5-HT2AR ([11C]Cimbi-36, n = 29), 5-HT4R ([11C]SB207145, n = 59), and 5-HTT ([11C]DASB, n = 100). We employed SUIT and FreeSurfer to delineate CV, CW, and CH and quantified mean standardized uptake values (SUV) and nondisplaceable neocortical binding potential (BPND). Statistical difference was assessed with paired nonparametric two-sided Wilcoxon signed-rank tests and multiple comparison corrected via false discovery rate. We demonstrate significant radioligand specific regional differences in cerebellar uptake. These differences persist when using different cerebellar regions for RTM, but the influence on the neocortical BPND is small. Nevertheless, our data highlight the importance of validating each radioligand carefully for defining the optimal reference region.
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Affiliation(s)
- Melanie Ganz
- Neurobiology Research Unit and Center for Integrated Molecular Brain Imaging, Rigshospitalet, Copenhagen, Denmark
| | - Ling Feng
- Neurobiology Research Unit and Center for Integrated Molecular Brain Imaging, Rigshospitalet, Copenhagen, Denmark
| | - Hanne Demant Hansen
- Neurobiology Research Unit and Center for Integrated Molecular Brain Imaging, Rigshospitalet, Copenhagen, Denmark
| | - Vincent Beliveau
- Neurobiology Research Unit and Center for Integrated Molecular Brain Imaging, Rigshospitalet, Copenhagen, Denmark
- Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Claus Svarer
- Neurobiology Research Unit and Center for Integrated Molecular Brain Imaging, Rigshospitalet, Copenhagen, Denmark
| | - Gitte M Knudsen
- Neurobiology Research Unit and Center for Integrated Molecular Brain Imaging, Rigshospitalet, Copenhagen, Denmark
- Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Douglas N Greve
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Boston, MA, USA
- Harvard Medical School, Boston, MA, USA
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12
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Jørgensen LM, Weikop P, Villadsen J, Visnapuu T, Ettrup A, Hansen HD, Baandrup AO, Andersen FL, Bjarkam CR, Thomsen C, Jespersen B, Knudsen GM. Cerebral 5-HT release correlates with [ 11C]Cimbi36 PET measures of 5-HT2A receptor occupancy in the pig brain. J Cereb Blood Flow Metab 2017; 37:425-434. [PMID: 26825776 PMCID: PMC5381441 DOI: 10.1177/0271678x16629483] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Positron emission tomography (PET) can, when used with appropriate radioligands, non-invasively generate temporal and spatial information about acute changes in brain neurotransmitter systems. We for the first time evaluate the novel 5-HT2A receptor agonist PET radioligand, [11C]Cimbi-36, for its sensitivity to detect changes in endogenous cerebral 5-HT levels, as induced by different pharmacological challenges. To enable a direct translation of PET imaging data to changes in brain 5-HT levels, we calibrated the [11C]Cimbi-36 PET signal in the pig brain by simultaneous measurements of extracellular 5-HT levels with microdialysis and [11C]Cimbi-36 PET after various acute interventions (saline, citalopram, citalopram + pindolol, fenfluramine). In a subset of pigs, para-chlorophenylalanine pretreatment was given to deplete cerebral 5-HT. The interventions increased the cerebral extracellular 5-HT levels to 2-11 times baseline, with fenfluramine being the most potent pharmacological enhancer of 5-HT release, and induced a varying degree of decline in [11C]Cimbi-36 binding in the brain, consistent with the occupancy competition model. The observed correlation between changes in the extracellular 5-HT level in the pig brain and the 5-HT2A receptor occupancy indicates that [11C]Cimbi-36 binding is sensitive to changes in endogenous 5-HT levels, although only detectable with PET when the 5-HT release is sufficiently high.
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Affiliation(s)
- Louise M Jørgensen
- 1 Neurobiology Research Unit, Rigshospitalet, Copenhagen, Denmark.,2 Faculty of Health and Medical Sciences, University of Copenhagen, Denmark
| | - Pia Weikop
- 3 The Laboratory of Neuropsychiatry, Department of Neuroscience and Pharmacology, University of Copenhagen, Denmark.,4 Psychiatric Centre Copenhagen, University of Copenhagen, Denmark
| | - Jonas Villadsen
- 1 Neurobiology Research Unit, Rigshospitalet, Copenhagen, Denmark
| | - Tanel Visnapuu
- 3 The Laboratory of Neuropsychiatry, Department of Neuroscience and Pharmacology, University of Copenhagen, Denmark.,5 Center for Excellence in Translational Medicine, University of Tartu, Estonia
| | - Anders Ettrup
- 1 Neurobiology Research Unit, Rigshospitalet, Copenhagen, Denmark
| | - Hanne D Hansen
- 1 Neurobiology Research Unit, Rigshospitalet, Copenhagen, Denmark
| | - Anders O Baandrup
- 6 Research Center for Advanced Imaging, Hospital of Køge and Roskilde, Roskilde, Denmark
| | | | | | - Carsten Thomsen
- 2 Faculty of Health and Medical Sciences, University of Copenhagen, Denmark.,9 Department of Radiology, Rigshospitalet, Copenhagen, Denmark
| | - Bo Jespersen
- 10 Department of Neurosurgery, Rigshospitalet, Copenhagen, Denmark
| | - Gitte M Knudsen
- 1 Neurobiology Research Unit, Rigshospitalet, Copenhagen, Denmark.,2 Faculty of Health and Medical Sciences, University of Copenhagen, Denmark
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13
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Slifstein M, Abi-Dargham A. Recent Developments in Molecular Brain Imaging of Neuropsychiatric Disorders. Semin Nucl Med 2016; 47:54-63. [PMID: 27987558 DOI: 10.1053/j.semnuclmed.2016.09.002] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Molecular imaging with PET or SPECT has been an important research tool in psychiatry for as long as these modalities have been available. Here, we discuss two areas of neuroimaging relevant to current psychiatry research. The first is the use of imaging to study neurotransmission. We discuss the use of pharmacologic probes to induce changes in levels of neurotransmitters that can be inferred through their effects on outcome measures of imaging experiments, from their historical origins focusing on dopamine transmission through recent developments involving serotonin, GABA, and glutamate. Next, we examine imaging of neuroinflammation in the context of psychiatry. Imaging markers of neuroinflammation have been studied extensively in other areas of brain research, but they have more recently attracted interest in psychiatry research, based on accumulating evidence that there may be an inflammatory component to some psychiatric conditions. Furthermore, new probes are under development that would allow unprecedented insights into cellular processes. In summary, molecular imaging would continue to offer great potential as a unique tool to further our understanding of brain function in health and disease.
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Affiliation(s)
- Mark Slifstein
- Department of Psychiatry, Columbia University Medical Center, New York, NY; New York State Psychiatric Institute, New York, NY; Department of Psychiatry, Stony Brook University, New York, NY.
| | - Anissa Abi-Dargham
- Department of Psychiatry, Columbia University Medical Center, New York, NY; Department of Radiology, Columbia University Medical Center, New York, NY; New York State Psychiatric Institute, New York, NY; Department of Psychiatry, Stony Brook University, New York, NY
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14
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Strupp-Levitsky M, Miller JM, Rubin-Falcone H, Zanderigo F, Milak MS, Sullivan G, Ogden RT, Oquendo MA, DeLorenzo C, Simpson N, Parsey RV, Mann JJ. Lack of association between the serotonin transporter and serotonin 1A receptor: an in vivo PET imaging study in healthy adults. Psychiatry Res 2016; 255:81-86. [PMID: 27567324 PMCID: PMC5175477 DOI: 10.1016/j.pscychresns.2016.08.002] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/06/2016] [Revised: 07/11/2016] [Accepted: 08/06/2016] [Indexed: 01/12/2023]
Abstract
The serotonin neurotransmitter system is modulated in part by the uptake of synaptically released serotonin (5-HT) by the serotonin transporter (5-HTT), and by specific serotonin autoreceptors such as the somatodendritic 5-HT1A receptor, which can limit serotonin neuron depolarization. However, little is known about how 5-HTT and 5-HT1A are related in vivo. To study this question, we reanalyzed positron emission tomography (PET) data obtained earlier in 40 healthy participants (21 females) using [(11)C]WAY-100635 for quantification of 5-HT1A binding and [(11)C](+)-McN-5652 for quantification of 5-HTT binding. We hypothesized negative correlations between 5-HT1A binding in the raphe nuclei (RN) and 5-HTT binding in RN terminal field regions. Controlling for sex, no significant correlations were found (all p>0.05). Similarly, an exploratory analysis correlating whole-brain voxel-wise 5-HTT binding with 5-HT1A binding in RN identified no significant clusters meeting our a priori statistical threshold. The lack of correlation between 5-HT1A and 5-HTT binding observed in the current study may be due to the different temporal responsiveness of regulatory processes controlling the somatodendritic 5-HT1A receptor and 5-HTT in response to changing availability of intrasynaptic serotonin.
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Affiliation(s)
- Michael Strupp-Levitsky
- Department of Molecular Imaging and Neuropathology, New York State Psychiatric Institute, 1051 Riverside Drive #42, New York, NY 10032, USA
| | - Jeffrey M Miller
- Department of Molecular Imaging and Neuropathology, New York State Psychiatric Institute, 1051 Riverside Drive #42, New York, NY 10032, USA; Department of Psychiatry, Columbia University, 1051 Riverside Drive #42, New York, NY 10032, USA.
| | - Harry Rubin-Falcone
- Department of Molecular Imaging and Neuropathology, New York State Psychiatric Institute, 1051 Riverside Drive #42, New York, NY 10032, USA; Department of Psychiatry, Columbia University, 1051 Riverside Drive #42, New York, NY 10032, USA
| | - Francesca Zanderigo
- Department of Molecular Imaging and Neuropathology, New York State Psychiatric Institute, 1051 Riverside Drive #42, New York, NY 10032, USA; Department of Psychiatry, Columbia University, 1051 Riverside Drive #42, New York, NY 10032, USA
| | - Matthew S Milak
- Department of Molecular Imaging and Neuropathology, New York State Psychiatric Institute, 1051 Riverside Drive #42, New York, NY 10032, USA; Department of Psychiatry, Columbia University, 1051 Riverside Drive #42, New York, NY 10032, USA
| | - Gregory Sullivan
- Department of Molecular Imaging and Neuropathology, New York State Psychiatric Institute, 1051 Riverside Drive #42, New York, NY 10032, USA; Department of Psychiatry, Columbia University, 1051 Riverside Drive #42, New York, NY 10032, USA
| | - R Todd Ogden
- Department of Molecular Imaging and Neuropathology, New York State Psychiatric Institute, 1051 Riverside Drive #42, New York, NY 10032, USA; Department of Biostatistics, Mailman School of Public Health, Columbia University, New York, NY, USA
| | - Maria A Oquendo
- Department of Molecular Imaging and Neuropathology, New York State Psychiatric Institute, 1051 Riverside Drive #42, New York, NY 10032, USA; Department of Psychiatry, Columbia University, 1051 Riverside Drive #42, New York, NY 10032, USA
| | - Christine DeLorenzo
- Now at Department of Psychiatry, Department of Radiology, Stony Brook Medicine, Stony Brook, NY, USA
| | - Norman Simpson
- Department of Molecular Imaging and Neuropathology, New York State Psychiatric Institute, 1051 Riverside Drive #42, New York, NY 10032, USA; Department of Psychiatry, Columbia University, 1051 Riverside Drive #42, New York, NY 10032, USA
| | - Ramin V Parsey
- Now at Department of Psychiatry, Department of Radiology, Stony Brook Medicine, Stony Brook, NY, USA
| | - J John Mann
- Department of Molecular Imaging and Neuropathology, New York State Psychiatric Institute, 1051 Riverside Drive #42, New York, NY 10032, USA; Department of Psychiatry, Columbia University, 1051 Riverside Drive #42, New York, NY 10032, USA
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15
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Mukherjee J, Bajwa AK, Wooten DW, Hillmer AT, Pan ML, Pandey SK, Saigal N, Christian BT. Comparative assessment of (18) F-Mefway as a serotonin 5-HT1A receptor PET imaging agent across species: Rodents, nonhuman primates, and humans. J Comp Neurol 2016; 524:1457-71. [PMID: 26509362 PMCID: PMC4783179 DOI: 10.1002/cne.23919] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2015] [Revised: 08/22/2015] [Accepted: 10/23/2015] [Indexed: 02/02/2023]
Abstract
We have developed (18) F-trans-Mefway ((18) F-Mefway) for positron emission tomography (PET) imaging studies of serotonin 5-HT1A receptors which are implicated in various brain functions. Translation of imaging the 5-HT1A receptor in animal models to humans will facilitate an understanding of the role of the receptor in human brain disorders. We report comparative brain distribution of (18) F-Mefway in normal mice, rats, monkeys, and healthy human volunteers. Mefway was found to be very selective, with subnanomolar affinity for the 5-HT1A receptor. Affinities of >55 nM were found for all other human-cloned receptor subtypes tested. Mefway was found to be a poor substrate (>30 μM) for the multidrug resistance 1 protein, suggesting low likelihood of brain uptake being affected by P-glycoprotein. Cerebellum was used as a reference region in all imaging studies across all species due to the low levels of (18) F-Mefway binding. Consistent binding of (18) F-Mefway in cortical regions, hippocampus, and raphe was observed across all species. (18) F-Mefway in the human brain regions correlated with the known postmortem distribution of 5-HT1A receptors. Quantitation of raphe was affected by the resolution of the PET scanners in rodents, whereas monkeys and humans showed a raphe to cerebellum ratio of approximately 3. (18) F-Mefway appears to be an effective 5-HT1A receptor imaging agent in all models, including humans. (18) F-Mefway therefore may be used to quantify 5-HT1A receptor distribution in brain regions for the study of various CNS disorders. J. Comp. Neurol. 524:1457-1471, 2016. © 2015 Wiley Periodicals, Inc.
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Affiliation(s)
- Jogeshwar Mukherjee
- Preclinical Imaging, Department of Radiological Sciences, University of California, Irvine, California, 92697-5000
| | - Alisha K Bajwa
- Preclinical Imaging, Department of Radiological Sciences, University of California, Irvine, California, 92697-5000
| | - Dustin W Wooten
- Department of Medical Physics and Waisman Center, University of Wisconsin, Madison, Wisconsin, 53705
| | - Ansel T Hillmer
- Department of Medical Physics and Waisman Center, University of Wisconsin, Madison, Wisconsin, 53705
| | - Min-Liang Pan
- Preclinical Imaging, Department of Radiological Sciences, University of California, Irvine, California, 92697-5000
| | - Suresh K Pandey
- Preclinical Imaging, Department of Radiological Sciences, University of California, Irvine, California, 92697-5000
| | - Neil Saigal
- Preclinical Imaging, Department of Radiological Sciences, University of California, Irvine, California, 92697-5000
| | - Bradley T Christian
- Department of Medical Physics and Waisman Center, University of Wisconsin, Madison, Wisconsin, 53705
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16
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Finnema SJ, Halldin C, Bang-Andersen B, Bundgaard C, Farde L. Serotonin transporter occupancy by escitalopram and citalopram in the non-human primate brain: a [(11)C]MADAM PET study. Psychopharmacology (Berl) 2015; 232:4159-67. [PMID: 25980484 DOI: 10.1007/s00213-015-3961-7] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/05/2015] [Accepted: 05/05/2015] [Indexed: 11/29/2022]
Abstract
RATIONALE A number of serotonin receptor positron emission tomography (PET) radioligands have been shown to be sensitive to changes in extracellular serotonin concentration, in a generalization of the well-known dopamine competition model. High doses of selective serotonin reuptake inhibitors (SSRIs) decrease serotonin receptor availability in monkey brain, consistent with increased serotonin concentrations. However, two recent studies on healthy human subjects, using a single, lower and clinically relevant SSRI dose, showed increased cortical serotonin receptor radioligand binding, suggesting potential decreases in serotonin concentration in projection regions when initiating treatment. OBJECTIVES The cross-species differential SSRI effect may be partly explained by serotonin transporter (SERT) occupancy in monkey brain being higher than is clinically relevant. We here determine SERT occupancy after single doses of escitalopram or citalopram by conducting PET measurements with [(11)C]MADAM in monkeys. Relationships between dose, plasma concentration and SERT occupancy were estimated by one-site binding analyses. Binding affinity was expressed as dose (ID50) or plasma concentration (K i) where 50 % SERT occupancy was achieved. RESULTS Estimated ID50 and K i values were 0.020 mg/kg and 9.6 nmol/L for escitalopram and 0.059 mg/kg and 9.7 nmol/L for citalopram, respectively. Obtained K i values are comparable to values reported in humans. CONCLUSIONS Escitalopram or citalopram doses nearly saturated SERT in previous monkey studies which examined serotonin sensitivity of receptor radioligands. PET-measured cross-species differential effects of SSRI on cortical serotonin concentration may thus be related to SSRI dose. Future monkey studies using SSRI doses inducing clinically relevant SERT occupancy may further illuminate the delayed onset of SSRI therapeutic effects.
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Affiliation(s)
- Sjoerd J Finnema
- Department of Clinical Neuroscience, Center for Psychiatric Research, Karolinska Institutet, Karolinska University Hospital, Building R5:02, SE-17176, Stockholm, Sweden. .,Department of Diagnostic Radiology, Yale University, New Haven, CT, USA.
| | - Christer Halldin
- Department of Clinical Neuroscience, Center for Psychiatric Research, Karolinska Institutet, Karolinska University Hospital, Building R5:02, SE-17176, Stockholm, Sweden
| | | | | | - Lars Farde
- Department of Clinical Neuroscience, Center for Psychiatric Research, Karolinska Institutet, Karolinska University Hospital, Building R5:02, SE-17176, Stockholm, Sweden.,AstraZeneca, Translational Science Center at Karolinska Institutet, Stockholm, Sweden
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17
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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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18
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Finnema SJ, Scheinin M, Shahid M, Lehto J, Borroni E, Bang-Andersen B, Sallinen J, Wong E, Farde L, Halldin C, Grimwood S. Application of cross-species PET imaging to assess neurotransmitter release in brain. Psychopharmacology (Berl) 2015; 232:4129-57. [PMID: 25921033 PMCID: PMC4600473 DOI: 10.1007/s00213-015-3938-6] [Citation(s) in RCA: 56] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/21/2015] [Accepted: 04/09/2015] [Indexed: 01/03/2023]
Abstract
RATIONALE This review attempts to summarize the current status in relation to the use of positron emission tomography (PET) imaging in the assessment of synaptic concentrations of endogenous mediators in the living brain. OBJECTIVES Although PET radioligands are now available for more than 40 CNS targets, at the initiation of the Innovative Medicines Initiative (IMI) "Novel Methods leading to New Medications in Depression and Schizophrenia" (NEWMEDS) in 2009, PET radioligands sensitive to an endogenous neurotransmitter were only validated for dopamine. NEWMEDS work-package 5, "Cross-species and neurochemical imaging (PET) methods for drug discovery", commenced with a focus on developing methods enabling assessment of changes in extracellular concentrations of serotonin and noradrenaline in the brain. RESULTS Sharing the workload across institutions, we utilized in vitro techniques with cells and tissues, in vivo receptor binding and microdialysis techniques in rodents, and in vivo PET imaging in non-human primates and humans. Here, we discuss these efforts and review other recently published reports on the use of radioligands to assess changes in endogenous levels of dopamine, serotonin, noradrenaline, γ-aminobutyric acid, glutamate, acetylcholine, and opioid peptides. The emphasis is on assessment of the availability of appropriate translational tools (PET radioligands, pharmacological challenge agents) and on studies in non-human primates and human subjects, as well as current challenges and future directions. CONCLUSIONS PET imaging directed at investigating changes in endogenous neurochemicals, including the work done in NEWMEDS, have highlighted an opportunity to further extend the capability and application of this technology in drug development.
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Affiliation(s)
- Sjoerd J. Finnema
- />Department of Clinical Neuroscience, Center for Psychiatric Research, Karolinska Institutet, Stockholm, Sweden
| | - Mika Scheinin
- />Department of Pharmacology, Drug Development and Therapeutics, University of Turku, Turku, Finland , />Unit of Clinical Pharmacology, Turku University Hospital, Turku, Finland
| | - Mohammed Shahid
- />Research and Development, Orion Corporation, Orion Pharma, Turku, Finland
| | - Jussi Lehto
- />Department of Pharmacology, Drug Development and Therapeutics, University of Turku, Turku, Finland
| | - Edilio Borroni
- />Neuroscience Department, Hoffman-La Roche, Basel, Switzerland
| | | | - Jukka Sallinen
- />Research and Development, Orion Corporation, Orion Pharma, Turku, Finland
| | - Erik Wong
- />Neuroscience Innovative Medicine Unit, AstraZeneca, Wilmington, DE USA
| | - Lars Farde
- />Department of Clinical Neuroscience, Center for Psychiatric Research, Karolinska Institutet, Stockholm, Sweden , />Translational Science Center at Karolinska Institutet, AstraZeneca, Stockholm, Sweden
| | - Christer Halldin
- />Department of Clinical Neuroscience, Center for Psychiatric Research, Karolinska Institutet, Stockholm, Sweden
| | - Sarah Grimwood
- Neuroscience Research Unit, Pfizer Inc, Cambridge, MA, USA. .,, 610 Main Street, Cambridge, MA, 02139, USA.
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19
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Hesse S, van de Giessen E, Zientek F, Petroff D, Winter K, Dickson JC, Tossici-Bolt L, Sera T, Asenbaum S, Darcourt J, Akdemir UO, Knudsen GM, Nobili F, Pagani M, Vander Borght T, Van Laere K, Varrone A, Tatsch K, Sabri O, Booij J. Association of central serotonin transporter availability and body mass index in healthy Europeans. Eur Neuropsychopharmacol 2014; 24:1240-7. [PMID: 24976619 DOI: 10.1016/j.euroneuro.2014.05.005] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/23/2013] [Revised: 04/09/2014] [Accepted: 05/09/2014] [Indexed: 01/24/2023]
Abstract
UNLABELLED Serotonin-mediated mechanisms, in particular via the serotonin transporter (SERT), are thought to have an effect on food intake and play an important role in the pathophysiology of obesity. However, imaging studies that examined the correlation between body mass index (BMI) and SERT are sparse and provided contradictory results. The aim of this study was to further test the association between SERT and BMI in a large cohort of healthy subjects. METHODS 127 subjects of the ENC DAT database (58 females, age 52 ± 18 years, range 20-83, BMI 25.2 ± 3.8 kg/m(2), range 18.2-41.1) were analysed using region-of-interest (ROI) and voxel-based approaches to calculate [(123)I]FP-CIT specific-to-nonspecific binding ratios (SBR) in the hypothalamus/thalamus and midbrain/brainstem as SERT-specific target regions. RESULTS In the voxel-based analysis, SERT availability and BMI were positively associated in the thalamus, but not in the midbrain. In the ROI-analysis, the interaction between gender and BMI showed a trend with higher correlation coefficient for men in the midbrain albeit not significant (0.033SBRm(2)/kg, p=0.1). CONCLUSIONS The data are in agreement with previous PET findings of an altered central serotonergic tone depending on BMI, as a probable pathophysiologic mechanism in obesity, and should encourage further clinical studies in obesity targeting the serotonergic system.
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Affiliation(s)
- Swen Hesse
- Department of Nuclear Medicine, University of Leipzig, Leipzig, Germany; Leipzig University Medical Center, Integrated Research and Treatment Centre (IFB) Adiposity Diseases, Leipzig, Germany.
| | - Elsmarieke van de Giessen
- Department of Nuclear Medicine, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Franziska Zientek
- Department of Nuclear Medicine, University of Leipzig, Leipzig, Germany
| | - David Petroff
- Department of Nuclear Medicine, University of Leipzig, Leipzig, Germany; Centre for Clinical Studies, Leipzig, Germany
| | - Karsten Winter
- Translational Centre for Regenerative Medicine (TRM) Leipzig, Germany
| | - John C Dickson
- Institute of Nuclear Medicine, University College London Hospital, London, UK
| | - Livia Tossici-Bolt
- Department of Medical Physics and Bioengineering, Southampton University Hospitals NHS Trust, Southampton, UK
| | - Terez Sera
- University of Szeged, Department of Nuclear Medicine and Euromedic Szeged, Szeged, Hungary
| | - Susanne Asenbaum
- Department of Nuclear Medicine, Medical University of Vienna, Austria
| | - Jacques Darcourt
- Nuclear Medicine Department, Centre Antoine Lacassagne, University of Nice-Sophia Antipolis, Nice, France
| | - Umit O Akdemir
- Department of Nuclear Medicine, Gazi University, Faculty of Medicine, Ankara, Turkey
| | - Gitte M Knudsen
- Neurobiology Research Unit, Rigshospitalet - University of Copenhagen, Copenhagen, Denmark
| | - Flavio Nobili
- Clinical Neurophysiology Unit, Department of Neuroscience, Ophthalmology and Genetics, San Martino Hospital, University of Genoa, Genoa, Italy
| | - Marco Pagani
- Department of Nuclear Medicine, Karolinska University Hospital, Stockholm, Sweden; Institute of Cognitive Sciences and Technologies, CNR, Rome & Padua, Italy
| | - Thierry Vander Borght
- Nuclear Medicine Division, Université Catholique de Louvain, Mont-Godinne Medical Center, Louvain-la-Neuve, Belgium
| | - Koen Van Laere
- Nuclear Medicine, University Hospital, K.U. Leuven, Leuven, Belgium
| | - Andrea Varrone
- Karolinska Institutet, Department of Clinical Neuroscience, Stockholm, Sweden
| | - Klaus Tatsch
- Department of Nuclear Medicine, University of Munich, Munich, Germany; Department of Nuclear Medicine, Municipal Hospital Karlsruhe Inc., Karlsruhe, Germany
| | - Osama Sabri
- Department of Nuclear Medicine, University of Leipzig, Leipzig, Germany; Leipzig University Medical Center, Integrated Research and Treatment Centre (IFB) Adiposity Diseases, Leipzig, Germany
| | - Jan Booij
- Department of Nuclear Medicine, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
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Central 5-HT4 receptor binding as biomarker of serotonergic tonus in humans: a [11C]SB207145 PET study. Mol Psychiatry 2014; 19:427-32. [PMID: 24189342 DOI: 10.1038/mp.2013.147] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/13/2013] [Revised: 08/10/2013] [Accepted: 09/09/2013] [Indexed: 01/22/2023]
Abstract
Identification of a biomarker that can inform on extracellular serotonin (5-HT) levels in the brains of living humans would enable greater understanding of the way brain circuits are modulated by serotonergic neurotransmission. Substantial evidence from studies in animals and humans indicates an inverse relationship between central 5-HT tonus and 5-HT type 4 receptor (5-HT4R) density, suggesting that 5-HT4R receptor density may be a biomarker marker for 5-HT tonus. Here, we investigated whether a 3-week administration of a selective serotonin reuptake inhibitor, expected to increase brain 5-HT levels, is associated with a decline in brain 5-HT4R binding. A total of 35 healthy men were studied in a placebo-controlled, randomized, double-blind study. Participants were assigned to receive 3 weeks of oral dosing with placebo or fluoxetine, 40 mg per day. Brain 5-HT4R binding was quantified at baseline and at follow-up with [(11)C]SB207145 positron emission tomography (PET). Three weeks of intervention with fluoxetine was associated with a 5.2% reduction in brain 5-HT4R binding (P=0.017), whereas placebo intervention did not change 5-HT4R binding (P=0.52). Our findings are consistent with a model, wherein the 5-HT4R density adjusts to changes in the extracellular 5-HT tonus. Our data demonstrate for the first time in humans that the imaging of central 5-HT4R binding may be used as an in vivo biomarker of the central 5-HT tonus.
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Shrestha SS, Liow JS, Lu S, Jenko K, Gladding RL, Svenningsson P, Morse CL, Zoghbi SS, Pike VW, Innis RB. (11)C-CUMI-101, a PET radioligand, behaves as a serotonin 1A receptor antagonist and also binds to α(1) adrenoceptors in brain. J Nucl Med 2014; 55:141-6. [PMID: 24385311 DOI: 10.2967/jnumed.113.125831] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
UNLABELLED The PET radioligand (11)C-CUMI-101 was previously suggested as a putative agonist radioligand for the serotonin 1A (5-hydroxytryptamine 1A [5-HT1A]) receptor in recombinant cells expressing human 5-HT1A receptor. However, a recent study showed that CUMI-101 behaved as a potent 5-HT1A receptor antagonist in rat brain. CUMI-101 also has moderate affinity (Ki = 6.75 nM) for α1 adrenoceptors measured in vitro. The current study examined the functional properties and selectivity of CUMI-101, both in vitro and in vivo. METHODS The functional assay was performed using (35)S-GTPγS (GTP is guanosine triphosphate) in primate brains. The cross-reactivity of CUMI-101 with α1 adrenoceptors was performed using in vitro radioligand binding studies in rat, monkey, and human brains as well as in vivo PET imaging in mouse, rat, and monkey brains. RESULTS CUMI-101 did not stimulate (35)S-GTPγS binding in primate brain, in contrast to 8-OH-DPAT, a potent 5-HT1A receptor agonist. Instead, CUMI-101 behaved as a potent 5-HT1A receptor antagonist by dose-dependently inhibiting 8-OH-DPAT-stimulated (35)S-GTPγS binding. Both in vitro and in vivo studies showed that CUMI-101 had significant α1 adrenoceptor cross-reactivity. On average, across all 3 species examined, cross-reactivity was highest in the thalamus (>45%) and lowest in the neocortex and cerebellum (<10%). PET imaging further confirmed that only preblocking with WAY-100635 plus prazosin decreased (11)C-CUMI-101 brain uptake to that of self-block. CONCLUSION CUMI-101 behaves as a 5-HT1A receptor antagonist in primate brain, with significant, regional-dependent α1 adrenoceptor cross-reactivity, limiting its potential use as a PET radioligand in humans.
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Affiliation(s)
- Stal Saurav Shrestha
- National Institute of Mental Health Intramural Research Program, Bethesda, Maryland; and
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Preclinical safety assessment of the 5-HT2A receptor agonist PET radioligand [ 11C]Cimbi-36. Mol Imaging Biol 2014; 15:376-83. [PMID: 23306971 DOI: 10.1007/s11307-012-0609-4] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
PURPOSE [11C]Cimbi-36 was recently developed as an agonist radioligand for brain imaging of serotonin 2A receptors (5-HT2A) with positron emission tomography (PET). This may be used to quantify the high-affinity state of 5-HT2A receptors and may have the potential to quantify changes in cerebral 5-HT levels in vivo. We here investigated safety aspects related to clinical use of [11C]Cimbi-36, including radiation dosimetry and in vivo pharmacology. PROCEDURES [11C]Cimbi-36 was injected in rats or pigs, and radiation dosimetry was examined by ex vivo dissection or with PET scanning, respectively. Based on animal data, the Organ Level INternal Dose Assessment software was used to estimate extrapolated human dosimetry for [11C]Cimbi-36. The 5-HT2A receptor agonist actions of [11C]Cimbi-36 in vivo pharmacological effects in mice elicited by increasing doses of Cimbi-36 were assessed with the head-twitch response (HTR). RESULTS The effective dose as extrapolated from both rat and pig data was low, 7.67 and 4.88 μSv/MBq, respectively. In addition, the estimated absorbed radiation dose to human target organs did not exceed safety levels. Administration of 0.5 mg/kg Cimbi-36 leads to significant HTR compared to saline, whereas 0.05 mg/kg Cimbi-36 (doses much larger than those given in conjunction with a PET scan) did not elicit a significant HTR. CONCLUSIONS Administration of tracer doses of [11C]Cimbi-36 does not seem to be associated with unusual radiation burden or adverse clinical effects.
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Kamlet AS, Neumann CN, Lee E, Carlin SM, Moseley CK, Stephenson N, Hooker JM, Ritter T. Application of palladium-mediated (18)F-fluorination to PET radiotracer development: overcoming hurdles to translation. PLoS One 2013; 8:e59187. [PMID: 23554994 PMCID: PMC3595243 DOI: 10.1371/journal.pone.0059187] [Citation(s) in RCA: 83] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2012] [Accepted: 02/12/2013] [Indexed: 11/18/2022] Open
Abstract
New chemistry methods for the synthesis of radiolabeled small molecules have the potential to impact clinical positron emission tomography (PET) imaging, if they can be successfully translated. However, progression of modern reactions from the stage of synthetic chemistry development to the preparation of radiotracer doses ready for use in human PET imaging is challenging and rare. Here we describe the process of and the successful translation of a modern palladium-mediated fluorination reaction to non-human primate (NHP) baboon PET imaging–an important milestone on the path to human PET imaging. The method, which transforms [18F]fluoride into an electrophilic fluorination reagent, provides access to aryl–18F bonds that would be challenging to synthesize via conventional radiochemistry methods.
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Affiliation(s)
- Adam S. Kamlet
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts, United States of America
| | - Constanze N. Neumann
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts, United States of America
| | - Eunsung Lee
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts, United States of America
| | - Stephen M. Carlin
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital and Harvard Medical School, Charlestown, Massachusetts, United States of America
| | - Christian K. Moseley
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital and Harvard Medical School, Charlestown, Massachusetts, United States of America
| | - Nickeisha Stephenson
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts, United States of America
| | - Jacob M. Hooker
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital and Harvard Medical School, Charlestown, Massachusetts, United States of America
- Division of Nuclear Medicine and Molecular Imaging, Department of Radiology, Massachusetts General Hospital, Boston, Massachusetts, United States of America
- * E-mail:
| | - Tobias Ritter
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts, United States of America
- Division of Nuclear Medicine and Molecular Imaging, Department of Radiology, Massachusetts General Hospital, Boston, Massachusetts, United States of America
- * E-mail:
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Kumar JSD, Parsey RV, Kassir SA, Majo VJ, Milak MS, Prabhakaran J, Simpson NR, Underwood MD, Mann JJ, Arango V. Autoradiographic evaluation of [3H]CUMI-101, a novel, selective 5-HT1AR ligand in human and baboon brain. Brain Res 2013; 1507:11-8. [PMID: 23454434 DOI: 10.1016/j.brainres.2013.02.035] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2012] [Revised: 02/14/2013] [Accepted: 02/20/2013] [Indexed: 01/01/2023]
Abstract
[11C]CUMI-101 is the first selective serotonin receptor (5-HT1AR) partial agonist radiotracer for positron emission tomography (PET) tested in vivo in nonhuman primates and humans. We evaluated specific binding of [3H]CUMI-101 by quantitative autoradiography studies in postmortem baboon and human brain sections using the 5-HT1AR antagonist WAY-100635 as a displacer. The regional and laminar distributions of [3H]CUMI-101 binding in baboon and human brain sections matched the known distribution of [3H]8-OH-DPAT and [3H]WAY-100635. Prazosin did not measurably displace [3H]CUMI-101 binding in baboon or human brain sections, thereby ruling out [3H]CUMI-101 binding to α1-adrenergic receptors. This study demonstrates that [11C]CUMI-101 is a selective 5-HT1AR ligand for in vivo and in vitro studies in baboon and human brain.
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Affiliation(s)
- J S Dileep Kumar
- Division of Molecular Imaging and Neuropathology, New York State Psychiatric Institute, New York, USA.
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