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Courault P, Lancelot S, Costes N, Colom M, Le Bars D, Redoute J, Gobert F, Dailler F, Isal S, Iecker T, Newman-Tancredi A, Merida I, Zimmer L. [ 18F]F13640: a selective agonist PET radiopharmaceutical for imaging functional 5-HT 1A receptors in humans. Eur J Nucl Med Mol Imaging 2023; 50:1651-1664. [PMID: 36656363 PMCID: PMC10119077 DOI: 10.1007/s00259-022-06103-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2022] [Accepted: 12/27/2022] [Indexed: 01/20/2023]
Abstract
PURPOSE F13640 (a.k.a. befiradol, NLX-112) is a highly selective 5-HT1A receptor ligand that was selected as a PET radiopharmaceutical-candidate based on animal studies. Due to its high efficacy agonist properties, [18F]F13640 binds preferentially to functional 5-HT1A receptors, which are coupled to intracellular G-proteins. Here, we characterize brain labeling of 5-HT1A receptors by [18F]F13640 in humans and describe a simplified model for its quantification. METHODS PET/CT and PET-MRI scans were conducted in a total of 13 healthy male volunteers (29 ± 9 years old), with arterial input functions (AIF) (n = 9) and test-retest protocol (n = 8). Several kinetic models were compared (one tissue compartment model, two-tissue compartment model, and Logan); two models with reference region were also evaluated: simplified reference tissue model (SRTM) and the logan reference model (LREF). RESULTS [18F]F13640 showed high uptake values in raphe nuclei and cortical regions. SRTM and LREF models showed a very high correlation with kinetic models using AIF. As concerns test-retest parameters and the prolonged binding kinetics of [18F]F13640, better reproducibility, and reliability were found with the LREF method. Cerebellum white matter and frontal lobe white matter stand out as suitable reference regions. CONCLUSION The favorable brain labeling and kinetic profile of [18F]F13640, its high receptor specificity and its high efficacy agonist properties open new perspectives for studying functionally active 5-HT1A receptors, unlike previous radiopharmaceuticals that act as antagonists. [18F]F13640's kinetic properties allow injection outside of the PET scanner with delayed acquisitions, facilitating the design of innovative longitudinal protocols in neurology and psychiatry. TRIAL REGISTRATION Trial Registration EudraCT 2017-002,722-21.
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Affiliation(s)
- Pierre Courault
- Université Claude Bernard Lyon 1, CNRS, INSERM, Lyon Neuroscience Research Center, Lyon, France.,Hospices Civils de Lyon (HCL), Lyon, France
| | - Sophie Lancelot
- Université Claude Bernard Lyon 1, CNRS, INSERM, Lyon Neuroscience Research Center, Lyon, France.,Hospices Civils de Lyon (HCL), Lyon, France.,CERMEP, Bron, France
| | - Nicolas Costes
- Université Claude Bernard Lyon 1, CNRS, INSERM, Lyon Neuroscience Research Center, Lyon, France.,CERMEP, Bron, France
| | | | - Didier Le Bars
- Hospices Civils de Lyon (HCL), Lyon, France.,CERMEP, Bron, France
| | | | - Florent Gobert
- Université Claude Bernard Lyon 1, CNRS, INSERM, Lyon Neuroscience Research Center, Lyon, France.,Hospices Civils de Lyon (HCL), Lyon, France
| | | | - Sibel Isal
- Hospices Civils de Lyon (HCL), Lyon, France
| | | | | | | | - Luc Zimmer
- Université Claude Bernard Lyon 1, CNRS, INSERM, Lyon Neuroscience Research Center, Lyon, France. .,Hospices Civils de Lyon (HCL), Lyon, France. .,CERMEP, Bron, France.
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2
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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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Aripiprazole Offsets Mutant ATXN3-Induced Motor Dysfunction by Targeting Dopamine D2 and Serotonin 1A and 2A Receptors in C. elegans. Biomedicines 2022; 10:biomedicines10020370. [PMID: 35203579 PMCID: PMC8962381 DOI: 10.3390/biomedicines10020370] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2021] [Revised: 01/26/2022] [Accepted: 01/27/2022] [Indexed: 01/14/2023] Open
Abstract
The atypical antipsychotic aripiprazole is a Food and Drug Administration-approved drug for the treatment of psychotic, mood, and other psychiatric disorders. Previous drug discovery efforts pinpointed aripiprazole as an effective suppressor of Machado–Joseph disease (MJD) pathogenesis, as its administration resulted in a reduced abundance and aggregation of mutant Ataxin-3 (ATXN3) proteins. Dopamine partial agonism and functional selectivity have been proposed as the main pharmacological mechanism of action of aripiprazole in the treatment of psychosis; however, this mechanism remains to be determined in the context of MJD. Here, we focus on confirming the efficacy of aripiprazole to reduce motor dysfunction in vivo, using a Caenorhabditis elegans (C. elegans) model of MJD, and on unveiling the drug targets required for its positive action against mutant ATXN3 pathogenesis. We employed pharmacogenetics and pharmacological approaches to identify which dopamine and serotonin receptors are critical for aripiprazole-mediated improvements in motor function. We demonstrated that dopamine D2-like and serotonin 5-HT1A and 5-HT2A receptors play important roles in this process. Our findings strengthen the relevance of dopaminergic and serotoninergic signaling modulation against mutant ATXN3-mediated pathogenesis. The identification of aripiprazole’s cellular targets, relevant for MJD and perhaps other neurodegenerative diseases, may pave the way for prospective drug discovery and development campaigns aiming to improve the features of this prototypical compound and reduce side effects not negligible in the case of aripiprazole.
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4
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Vidal B, Levigoureux E, Chaib S, Bouillot C, Billard T, Newman-Tancredi A, Zimmer L. Different Alterations of Agonist and Antagonist Binding to 5-HT1A Receptor in a Rat Model of Parkinson’s Disease and Levodopa-Induced Dyskinesia: A MicroPET Study. JOURNAL OF PARKINSONS DISEASE 2021; 11:1257-1269. [DOI: 10.3233/jpd-212580] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Background: The gold-standard treatment for Parkinson’s disease is L-DOPA, which in the long term often leads to levodopa-induced dyskinesia. Serotonergic neurons are partially responsible for this, by converting L-DOPA into dopamine leading to its uncontrolled release as a “false neurotransmitter”. The stimulation of 5-HT1A receptors can reduce involuntary movements but this mechanism is poorly understood. Objective: This study aimed to investigate the functionality of 5-HT1A receptors using positron emission tomography in hemiparkinsonian rats with or without dyskinesia induced by 3-weeks daily treatment with L-DOPA. Imaging sessions were performed “off” L-DOPA. Methods: Each rat underwent a positron emission tomography scan with [18F]F13640, a 5-HT1AR agonist which labels receptors in a high affinity state for agonists, or with [18F]MPPF, a 5-HT1AR antagonist which labels all the receptors. Results: There were decreases of [18F]MPPF binding in hemiparkinsonian rats in cortical areas. In dyskinetic animals, changes were slighter but also found in other regions. In hemiparkinsonian rats, [18F]F13640 uptake was decreased bilaterally in the globus pallidus and thalamus. On the non-lesioned side, binding was increased in the insula, the hippocampus and the amygdala. In dyskinetic animals, [18F]F13640 binding was strongly increased in cortical and limbic areas, especially in the non-lesioned side. Conclusion: These data suggest that agonist and antagonist 5-HT1A receptor-binding sites are differently modified in Parkinson’s disease and levodopa-induced dyskinesia. In particular, these observations suggest a substantial involvement of the functional state of 5-HT1AR in levodopa-induced dyskinesia and emphasize the need to characterize this state using agonist radiotracers in physiological and pathological conditions.
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Affiliation(s)
- Benjamin Vidal
- Lyon Neuroscience Research Center, Université de Lyon, Université Claude Bernard Lyon 1, CNRS, INSERM, Lyon, France
| | - Elise Levigoureux
- Lyon Neuroscience Research Center, Université de Lyon, Université Claude Bernard Lyon 1, CNRS, INSERM, Lyon, France
- Hospices Civils de Lyon, Lyon, France
| | - Sarah Chaib
- Lyon Neuroscience Research Center, Université de Lyon, Université Claude Bernard Lyon 1, CNRS, INSERM, Lyon, France
- Hospices Civils de Lyon, Lyon, France
| | | | - Thierry Billard
- CERMEP-Imaging Platform, Bron, France
- Institute of Chemistry and Biochemistry, Université de Lyon, CNRS, Villeurbanne, France
| | | | - Luc Zimmer
- Lyon Neuroscience Research Center, Université de Lyon, Université Claude Bernard Lyon 1, CNRS, INSERM, Lyon, France
- Hospices Civils de Lyon, Lyon, France
- CERMEP-Imaging Platform, Bron, France
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5
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Pereira-Sousa J, Ferreira-Lomba B, Bellver-Sanchis A, Vilasboas-Campos D, Fernandes JH, Costa MD, Varney MA, Newman-Tancredi A, Maciel P, Teixeira-Castro A. Identification of the 5-HT 1A serotonin receptor as a novel therapeutic target in a C. elegans model of Machado-Joseph disease. Neurobiol Dis 2021; 152:105278. [PMID: 33516872 DOI: 10.1016/j.nbd.2021.105278] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2020] [Revised: 01/15/2021] [Accepted: 01/24/2021] [Indexed: 12/18/2022] Open
Abstract
Machado-Joseph disease (MJD) or Spinocerebellar ataxia type 3 (SCA3) is a progressive neurodegenerative disorder that affects movement coordination leading to a premature death. Despite several efforts, no disease-modifying treatment is yet available for this disease. Previous studies pinpointed the modulation of serotonergic signaling, through pharmacological inhibition of the serotonin transporter SERT, as a promising therapeutic approach for MJD/SCA3. Here, we describe the 5-HT1A receptor as a novel therapeutic target in MJD, using a C. elegans model of ATXN3 proteotoxicity. Chronic and acute administration of befiradol (also known as NLX-112), a highly specific 5-HT1A agonist, rescued motor function and suppressed mutant ATXN3 aggregation. This action required the 5-HT1A receptor orthologue in the nematode, SER-4. Tandospirone, a clinically tested 5-HT1A receptor partial agonist, showed a limited impact on animals' motor dysfunction on acute administration and a broader receptor activation profile upon chronic treatment, its effect depending on 5-HT1A but also on the 5-HT6/SER-5 and 5-HT7/SER-7 receptors. Our results support high potency and specificity of befiradol for activation of 5-HT1A/SER-4 receptors and highlight the contribution of the auto- and hetero-receptor function to the therapeutic outcome in this MJD model. Our study deepens the understanding of serotonergic signaling modulation in the suppression of ATXN3 proteotoxicity and suggests that a potent and selective 5-HT1A receptor agonist such as befiradol could constitute a promising therapeutic agent for MJD.
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Affiliation(s)
- Joana Pereira-Sousa
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, Braga, Portugal; ICVS/3B's - PT Government Associate Laboratory Braga/Guimarães, Portugal; Behavioral & Molecular Lab (Bn'ML), University of Minho, Braga, Portugal
| | - Bruna Ferreira-Lomba
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, Braga, Portugal; ICVS/3B's - PT Government Associate Laboratory Braga/Guimarães, Portugal
| | - Aina Bellver-Sanchis
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, Braga, Portugal; ICVS/3B's - PT Government Associate Laboratory Braga/Guimarães, Portugal
| | - Daniela Vilasboas-Campos
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, Braga, Portugal; ICVS/3B's - PT Government Associate Laboratory Braga/Guimarães, Portugal
| | - Jorge H Fernandes
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, Braga, Portugal; ICVS/3B's - PT Government Associate Laboratory Braga/Guimarães, Portugal
| | - Marta D Costa
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, Braga, Portugal; ICVS/3B's - PT Government Associate Laboratory Braga/Guimarães, Portugal
| | | | | | - Patrícia Maciel
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, Braga, Portugal; ICVS/3B's - PT Government Associate Laboratory Braga/Guimarães, Portugal.
| | - Andreia Teixeira-Castro
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, Braga, Portugal; ICVS/3B's - PT Government Associate Laboratory Braga/Guimarães, Portugal.
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6
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Razakarivony O, Newman-Tancredi A, Zimmer L. Towards in vivo imaging of functionally active 5-HT 1A receptors in schizophrenia: concepts and challenges. Transl Psychiatry 2021; 11:22. [PMID: 33414418 PMCID: PMC7791062 DOI: 10.1038/s41398-020-01119-3] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/05/2020] [Revised: 11/13/2020] [Accepted: 11/20/2020] [Indexed: 12/18/2022] Open
Abstract
The serotonin 5-HT1A receptor has attracted wide attention as a target for treatment of psychiatric disorders. Although this receptor is important in the pharmacological mechanisms of action of new-generation antipsychotics, its characterization remains incomplete. Studies based on in vitro molecular imaging on brain tissue by autoradiography, and more recently in vivo PET imaging, have not yielded clear results, in particular due to the limitations of current 5-HT1A radiotracers, which lack specificity and/or bind to all 5-HT1A receptors, regardless of their functional status. The new concept of PET neuroimaging of functionally active G-protein-coupled receptors makes it possible to revisit PET brain exploration by enabling new research paradigms. For the 5-HT1A receptor it is now possible to use [18F]-F13640, a 5-HT1A receptor radioligand with high efficacy agonist properties, to specifically visualize and quantify functionally active receptors, and to relate this information to subjects' pathophysiological or pharmacological state. We therefore propose imaging protocols to follow changes in the pattern of functional 5-HT1A receptors in relation to mood deficits or cognitive processes. This could allow improved discrimination of different schizophrenia phenotypes and greater understanding of the basis of therapeutic responses to antipsychotic drugs. Finally, as well as targeting functionally active receptors to gain insights into the role of 5-HT1A receptors, the concept can also be extended to the study of other receptors involved in the pathophysiology or therapy of psychiatric disorders.
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Affiliation(s)
- Oriane Razakarivony
- grid.25697.3f0000 0001 2172 4233Université de Lyon, Lyon Neuroscience Research Center, INSERM, CNRS, Lyon, France ,grid.413852.90000 0001 2163 3825Hospices Civils de Lyon, Lyon, France
| | | | - Luc Zimmer
- Université de Lyon, Lyon Neuroscience Research Center, INSERM, CNRS, Lyon, France. .,Hospices Civils de Lyon, Lyon, France. .,CERMEP-Imagerie du Vivant, Bron, France. .,French National Institute for Nuclear Science and Technology, CEA Saclay, Gif-sur-Yvette, France.
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7
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Li J, Chen L, Li G, Chen X, Hu S, Zheng L, Luria V, Lv J, Sun Y, Xu Y, Yu Y. Sub-Acute Treatment of Curcumin Derivative J147 Ameliorates Depression-Like Behavior Through 5-HT 1A-Mediated cAMP Signaling. Front Neurosci 2020; 14:701. [PMID: 32733195 PMCID: PMC7360862 DOI: 10.3389/fnins.2020.00701] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2020] [Accepted: 06/09/2020] [Indexed: 12/14/2022] Open
Abstract
Background Major depressive disorder (MDD) is a severe mental disorder related to the deficiency of monoamine neurotransmitters, particularly to abnormalities of 5-HT (5-hydroxytryptamine, serotonin) and its receptors. Our previous study suggested that acute treatment with a novel curcumin derivative J147 exhibited antidepressant-like effects by increasing brain derived neurotrophic factor (BDNF) level in the hippocampus of mice. The present study expanded upon our previous findings and investigated the antidepressant-like effects of sub-acute treatment of J147 for 3 days in male ICR mice and its possible relevancy to 5-HT1A and 5-HT1B receptors and downstream cAMP-BDNF signaling. Methods J147 at doses of 1, 3, and 9 mg/kg (via gavage) was administered for 3 days, and the anti-immobility time in the forced swimming and tail suspension tests (FST and TST) was recorded. The radioligand binding assay was used to determine the affinity of J147 to 5-HT1A and 5-HT1B receptor. Moreover, 5-HT1A or 5-HT1B agonist or its antagonist was used to determine which 5-HT receptor subtype is involved in the antidepressant-like effects of J147. The downstream signaling molecules such as cAMP, PKA, pCREB, and BDNF were also measured to determine the mechanism of action. Results The results demonstrated that sub-acute treatment of J147 remarkably decreased the immobility time in both the FST and TST in a dose-dependent manner. J147 displayed high affinity in vitro to 5-HT1A receptor prepared from mice cortical tissue and was less potent at 5-HT1B receptor. These effects of J147 were blocked by pretreatment with a 5-HT1A antagonist NAD-299 and enhanced by a 5-HT1A agonist 8-OH-DPAT. However, 5-HT1B receptor antagonist NAS-181 did not appreciably alter the effects of J147 on depression-like behaviors. Moreover, pretreatment with NAD-299 blocked J147-induced increases in cAMP, PKA, pCREB, and BDNF expression in the hippocampus, while 8-OH-DPAT enhanced the effects of J147 on these proteins’ expression. Conclusion The results suggest that J147 induces rapid antidepressant-like effects during a 3-day treatment period without inducing drug tolerance. These effects might be mediated by 5-HT1A-dependent cAMP/PKA/pCREB/BDNF signaling.
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Affiliation(s)
- Jianxin Li
- Department of Gastroenterology, Wenzhou No. 3 Clinical Institute Affiliated to Wenzhou Medical University, Wenzhou People's Hospital, Wenzhou, China
| | - Ling Chen
- Department of Clinical Pharmacology, Key Laboratory of Clinical Cancer Pharmacology and Toxicology Research of Zhejiang Province, Affiliated Hangzhou First People's Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Gaowen Li
- Ningbo College of Health Sciences, Ningbo, China.,Department of Pharmaceutical Sciences, School of Pharmacy & Pharmaceutical Sciences, University at Buffalo, The State University of New York, Buffalo, NY, United States
| | - Xiaojuan Chen
- Department of Gastroenterology, Wenzhou No. 3 Clinical Institute Affiliated to Wenzhou Medical University, Wenzhou People's Hospital, Wenzhou, China
| | - Sisi Hu
- Department of Gastroenterology, Wenzhou No. 3 Clinical Institute Affiliated to Wenzhou Medical University, Wenzhou People's Hospital, Wenzhou, China
| | - Liang Zheng
- Department of Gastroenterology, Wenzhou No. 3 Clinical Institute Affiliated to Wenzhou Medical University, Wenzhou People's Hospital, Wenzhou, China
| | - Victor Luria
- Department of Systems Biology, Harvard Medical School, Boston, MA, United States
| | - Jinpeng Lv
- Department of Pharmaceutical Sciences, School of Pharmacy & Pharmaceutical Sciences, University at Buffalo, The State University of New York, Buffalo, NY, United States.,College of Pharmaceutical Engineering and Life Sciences, Changzhou University, Changzhou, China
| | - Yindi Sun
- Department of Traditional Medical Orthopedics, Honghui Hospital, Xi'an Jiaotong University, Xi'an, China
| | - Ying Xu
- Department of Pharmaceutical Sciences, School of Pharmacy & Pharmaceutical Sciences, University at Buffalo, The State University of New York, Buffalo, NY, United States
| | - Yingcong Yu
- Department of Gastroenterology, Wenzhou No. 3 Clinical Institute Affiliated to Wenzhou Medical University, Wenzhou People's Hospital, Wenzhou, China
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8
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Unterholzner J, Gryglewski G, Philippe C, Seiger R, Pichler V, Godbersen GM, Berroterán-Infante N, Murgaš M, Hahn A, Wadsak W, Mitterhauser M, Kasper S, Lanzenberger R. Topologically Guided Prioritization of Candidate Gene Transcripts Coexpressed with the 5-HT1A Receptor by Combining In Vivo PET and Allen Human Brain Atlas Data. Cereb Cortex 2020; 30:3771-3780. [PMID: 31989157 PMCID: PMC7232988 DOI: 10.1093/cercor/bhz341] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2019] [Revised: 11/25/2019] [Indexed: 12/20/2022] Open
Abstract
The serotonin-1A receptor (5-HT1AR) represents a viable target in the treatment of disorders of the brain. However, development of psychiatric drugs continues to be hindered by the relative inaccessibility of brain tissue. Although the efficacy of drugs selective for the 5-HT1AR has not been proven, research continues to focus on drugs that influence this receptor subtype. To further knowledge on this topic, we investigated the topological coexpression patterns of the 5-HT1AR. We calculated Spearman’s rho for the correlation of positron emission tomography-binding potentials (BPND) of the 5-HT1AR assessed in 30 healthy subjects using the tracer [carbonyl-11C]WAY-100635 and predicted whole-brain mRNA expression of 18 686 genes. After applying a threshold of r > 0.3 in a leave-one-out cross-validation of the prediction of mRNA expression, genes with ρ ≥ 0.7 were considered to be relevant. In cortical regions, 199 genes showed high correlation with the BPND of the 5-HT1AR, in subcortical regions 194 genes. Using our approach, we could consolidate the role of BDNF and implicate new genes (AnxA8, NeuroD2) in serotonergic functioning. Despite its explorative nature, the analysis can be seen as a gene prioritization approach to reduce the number of genes potentially connected to 5-HT1AR functioning and guide future in vitro studies.
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Affiliation(s)
- Jakob Unterholzner
- Department of Psychiatry and Psychotherapy, Medical University of Vienna, Währinger Gürtel 18-20, 1090, Vienna, Austria
| | - Gregor Gryglewski
- Department of Psychiatry and Psychotherapy, Medical University of Vienna, Währinger Gürtel 18-20, 1090, Vienna, Austria
| | - Cecile Philippe
- Division of Nuclear Medicine, Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, Währinger Gürtel 18-20, 1090, Vienna, Austria
| | - Rene Seiger
- Department of Psychiatry and Psychotherapy, Medical University of Vienna, Währinger Gürtel 18-20, 1090, Vienna, Austria
| | - Verena Pichler
- Division of Nuclear Medicine, Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, Währinger Gürtel 18-20, 1090, Vienna, Austria
| | - Godber M Godbersen
- Department of Psychiatry and Psychotherapy, Medical University of Vienna, Währinger Gürtel 18-20, 1090, Vienna, Austria
| | - Neydher Berroterán-Infante
- Division of Nuclear Medicine, Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, Währinger Gürtel 18-20, 1090, Vienna, Austria
| | - Matej Murgaš
- Department of Psychiatry and Psychotherapy, Medical University of Vienna, Währinger Gürtel 18-20, 1090, Vienna, Austria
| | - Andreas Hahn
- Department of Psychiatry and Psychotherapy, Medical University of Vienna, Währinger Gürtel 18-20, 1090, Vienna, Austria
| | - Wolfgang Wadsak
- Division of Nuclear Medicine, Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, Währinger Gürtel 18-20, 1090, Vienna, Austria.,Centre for Biomarker Research in Medicine (CBmed), Stiftingtalstrasse 5, 8010, Graz, Austria
| | - Markus Mitterhauser
- Division of Nuclear Medicine, Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, Währinger Gürtel 18-20, 1090, Vienna, Austria.,Ludwig Boltzmann Institute Applied Diagnostics, Währinger Gürtel 18-20, 1090, Vienna, Austria
| | - Siegfried Kasper
- Department of Psychiatry and Psychotherapy, Medical University of Vienna, Währinger Gürtel 18-20, 1090, Vienna, Austria
| | - Rupert Lanzenberger
- Department of Psychiatry and Psychotherapy, Medical University of Vienna, Währinger Gürtel 18-20, 1090, Vienna, Austria
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9
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Liu Y, Liu J, Jiao SR, Liu X, Guo Y, Zhang J, Yang J, Xie W, Wang HS, Zhang L. Serotonin1A receptors in the dorsal hippocampus regulate working memory and long-term habituation in the hemiparkinsonian rats. Behav Brain Res 2019; 376:112207. [DOI: 10.1016/j.bbr.2019.112207] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2019] [Revised: 08/30/2019] [Accepted: 08/30/2019] [Indexed: 12/12/2022]
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10
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Colom M, Vidal B, Zimmer L. Is There a Role for GPCR Agonist Radiotracers in PET Neuroimaging? Front Mol Neurosci 2019; 12:255. [PMID: 31680859 PMCID: PMC6813225 DOI: 10.3389/fnmol.2019.00255] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2019] [Accepted: 10/02/2019] [Indexed: 12/30/2022] Open
Abstract
Positron emission tomography (PET) is a molecular imaging modality that enables in vivo exploration of metabolic processes and especially the pharmacology of neuroreceptors. G protein-coupled receptors (GPCRs) play an important role in numerous pathophysiologic disorders of the central nervous system. Thus, they are targets of choice in PET imaging to bring proof concept of change in density in pathological conditions or in pharmacological challenge. At present, most radiotracers are antagonist ligands. In vitro data suggest that properties differ between GPCR agonists and antagonists: antagonists bind to receptors with a single affinity, whereas agonists are characterized by two different affinities: high affinity for receptors that undergo functional coupling to G-proteins, and low affinity for those that are not coupled. In this context, agonist radiotracers may be useful tools to give functional images of GPCRs in the brain, with high sensitivity to neurotransmitter release. Here, we review all existing PET radiotracers used from animals to humans and their role for understanding the ligand-receptor paradigm of GPCR in comparison with corresponding antagonist radiotracers.
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Affiliation(s)
- Matthieu Colom
- Lyon Neuroscience Research Center, INSERM, CNRS, Université de Lyon, Lyon, France.,CERMEP, Hospices Civils de Lyon, Bron, France
| | - Benjamin Vidal
- Lyon Neuroscience Research Center, INSERM, CNRS, Université de Lyon, Lyon, France
| | - Luc Zimmer
- Lyon Neuroscience Research Center, INSERM, CNRS, Université de Lyon, Lyon, France.,CERMEP, Hospices Civils de Lyon, Bron, France.,Institut National des Sciences et Techniques Nucléaires, CEA Saclay, Gif-sur-Yvette, France
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11
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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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12
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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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13
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Komorowski A, James GM, Philippe C, Gryglewski G, Bauer A, Hienert M, Spies M, Kautzky A, Vanicek T, Hahn A, Traub-Weidinger T, Winkler D, Wadsak W, Mitterhauser M, Hacker M, Kasper S, Lanzenberger R. Association of Protein Distribution and Gene Expression Revealed by PET and Post-Mortem Quantification in the Serotonergic System of the Human Brain. Cereb Cortex 2018; 27:117-130. [PMID: 27909009 PMCID: PMC5939202 DOI: 10.1093/cercor/bhw355] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2016] [Indexed: 12/12/2022] Open
Abstract
Regional differences in posttranscriptional mechanisms may influence in vivo protein densities. The association of positron emission tomography (PET) imaging data from 112 healthy controls and gene expression values from the Allen Human Brain Atlas, based on post-mortem brains, was investigated for key serotonergic proteins. PET binding values and gene expression intensities were correlated for the main inhibitory (5-HT1A) and excitatory (5-HT2A) serotonin receptor, the serotonin transporter (SERT) as well as monoamine oxidase-A (MAO-A), using Spearman's correlation coefficients (rs) in a voxel-wise and region-wise analysis. Correlations indicated a strong linear relationship between gene and protein expression for both the 5-HT1A (voxel-wise rs = 0.71; region-wise rs = 0.93) and the 5-HT2A receptor (rs = 0.66; 0.75), but only a weak association for MAO-A (rs = 0.26; 0.66) and no clear correlation for SERT (rs = 0.17; 0.29). Additionally, region-wise correlations were performed using mRNA expression from the HBT, yielding comparable results (5-HT1Ars = 0.82; 5-HT2Ars = 0.88; MAO-A rs = 0.50; SERT rs = -0.01). The SERT and MAO-A appear to be regulated in a region-specific manner across the whole brain. In contrast, the serotonin-1A and -2A receptors are presumably targeted by common posttranscriptional processes similar in all brain areas suggesting the applicability of mRNA expression as surrogate parameter for density of these proteins.
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Affiliation(s)
- A Komorowski
- Department of Psychiatry and Pychotherapy, Division of Biological Psychiatry, Medical University of Vienna, Währinger Gürtel 18-20, 1090 Vienna, Austria
| | - G M James
- Department of Psychiatry and Pychotherapy, Division of Biological Psychiatry, Medical University of Vienna, Währinger Gürtel 18-20, 1090 Vienna, Austria
| | - C Philippe
- Department of Biomedical Imaging and Image-guided Therapy, Division of Nuclear Medicine, Medical University of Vienna, Währinger Gürtel 18-20, 1090 Vienna, Austria
| | - G Gryglewski
- Department of Psychiatry and Pychotherapy, Division of Biological Psychiatry, Medical University of Vienna, Währinger Gürtel 18-20, 1090 Vienna, Austria
| | - A Bauer
- Institute of Neuroscience and Medicine (INM-2), Research Centre Jülich, 52425 Jülich, Germany
| | - M Hienert
- Department of Psychiatry and Pychotherapy, Division of Biological Psychiatry, Medical University of Vienna, Währinger Gürtel 18-20, 1090 Vienna, Austria
| | - M Spies
- Department of Psychiatry and Pychotherapy, Division of Biological Psychiatry, Medical University of Vienna, Währinger Gürtel 18-20, 1090 Vienna, Austria
| | - A Kautzky
- Department of Psychiatry and Pychotherapy, Division of Biological Psychiatry, Medical University of Vienna, Währinger Gürtel 18-20, 1090 Vienna, Austria
| | - T Vanicek
- Department of Psychiatry and Pychotherapy, Division of Biological Psychiatry, Medical University of Vienna, Währinger Gürtel 18-20, 1090 Vienna, Austria
| | - A Hahn
- Department of Psychiatry and Pychotherapy, Division of Biological Psychiatry, Medical University of Vienna, Währinger Gürtel 18-20, 1090 Vienna, Austria
| | - T Traub-Weidinger
- Department of Biomedical Imaging and Image-guided Therapy, Division of Nuclear Medicine, Medical University of Vienna, Währinger Gürtel 18-20, 1090 Vienna, Austria
| | - D Winkler
- Department of Psychiatry and Pychotherapy, Division of Biological Psychiatry, Medical University of Vienna, Währinger Gürtel 18-20, 1090 Vienna, Austria
| | - W Wadsak
- Department of Biomedical Imaging and Image-guided Therapy, Division of Nuclear Medicine, Medical University of Vienna, Währinger Gürtel 18-20, 1090 Vienna, Austria
| | - M Mitterhauser
- Department of Biomedical Imaging and Image-guided Therapy, Division of Nuclear Medicine, Medical University of Vienna, Währinger Gürtel 18-20, 1090 Vienna, Austria
| | - M Hacker
- Department of Biomedical Imaging and Image-guided Therapy, Division of Nuclear Medicine, Medical University of Vienna, Währinger Gürtel 18-20, 1090 Vienna, Austria
| | - S Kasper
- Department of Psychiatry and Pychotherapy, Division of Biological Psychiatry, Medical University of Vienna, Währinger Gürtel 18-20, 1090 Vienna, Austria
| | - R Lanzenberger
- Department of Psychiatry and Pychotherapy, Division of Biological Psychiatry, Medical University of Vienna, Währinger Gürtel 18-20, 1090 Vienna, Austria
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14
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Vidal B, Sebti J, Verdurand M, Fieux S, Billard T, Streichenberger N, Troakes C, Newman-Tancredi A, Zimmer L. Agonist and antagonist bind differently to 5-HT1A receptors during Alzheimer's disease: A post-mortem study with PET radiopharmaceuticals. Neuropharmacology 2016; 109:88-95. [PMID: 27183968 DOI: 10.1016/j.neuropharm.2016.05.009] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2016] [Revised: 05/03/2016] [Accepted: 05/13/2016] [Indexed: 11/30/2022]
Abstract
PET imaging studies using 5-HT1A receptor radiotracers show a decreased density of this receptor in hippocampi of patients with Alzheimer's disease (AD) at advanced stages. However, current 5-HT1A receptor radiopharmaceuticals used in neuroimaging are antagonists, thought to bind to 5-HT1A receptors in different functional states (i.e., both the one which displays high affinity for agonists and is thought to mediate receptor activation, as well as the state which has low affinity for agonists). Comparing the PET imaging obtained using an agonist radiotracer, which binds selectively to functional receptors, with the PET imaging obtained using an antagonist radiotracer would therefore provide original information on 5-HT1A receptor impairment during AD. Quantitative autoradiography using [(18)F]F13640 and [(18)F]MPPF, a 5-HT1A agonist and antagonist, respectively, was measured in hippocampi of patients with AD (n = 25, at different Braak stages) and control subjects (n = 9). The neuronal density was measured in the same tissues by NeuN immunohistochemistry. The specific binding of both radiotracers was determined by addition of WAY-100635, a selective 5-HT1A receptor antagonist. The autoradiography distribution of both 5-HT1A PET radiotracers varied across hippocampus regions. The highest binding density was in the pyramidal layer of CA1. Incubation with Gpp(NH)p, a non-hydrolysable analogue of GTP, reduced significantly [(18)F]F13640 binding in hippocampal regions, confirming its preferential interaction with G-coupled receptors, and slightly increased [(18)F]MPPF binding. In the CA1 subfield, [(18)F]F13640 binding was significantly decreased at Braak stages I/II (-19%), Braak stages III/IV (-23%), and Braak stages V/VI (-36%) versus control. In contrast, [(18)F]MPPF binding was statistically reduced only at the most advanced Braak stages V/VI compared to control (-33%). Since [(18)F]F13640 and [(18)F]MPPF can be used in vivo in humans, this neuropharmacological paradigm supports testing the concept of functional imaging using agonist radiopharmaceuticals in future clinical studies.
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Affiliation(s)
- Benjamin Vidal
- Lyon Neuroscience Research Center, Université Claude Bernard Lyon1, CNRS, INSERM, Lyon, France
| | - Johan Sebti
- Lyon Neuroscience Research Center, Université Claude Bernard Lyon1, CNRS, INSERM, Lyon, France; Hospices Civils de Lyon, Lyon, France
| | - Mathieu Verdurand
- Lyon Neuroscience Research Center, Université Claude Bernard Lyon1, CNRS, INSERM, Lyon, France
| | - Sylvain Fieux
- Lyon Neuroscience Research Center, Université Claude Bernard Lyon1, CNRS, INSERM, Lyon, France; CERMEP-Imaging Platform, Lyon, France
| | - Thierry Billard
- CERMEP-Imaging Platform, Lyon, France; Institute of Chemistry and Biochemistry, Université Claude Bernard Lyon 1, CNRS, Villeurbanne, France
| | | | - Claire Troakes
- MRC London Neurodegenerative Diseases Brain Bank, King's College London, UK
| | | | - Luc Zimmer
- Lyon Neuroscience Research Center, Université Claude Bernard Lyon1, CNRS, INSERM, Lyon, France; Hospices Civils de Lyon, Lyon, France; CERMEP-Imaging Platform, Lyon, France.
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15
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Pike VW. Considerations in the Development of Reversibly Binding PET Radioligands for Brain Imaging. Curr Med Chem 2016; 23:1818-69. [PMID: 27087244 PMCID: PMC5579844 DOI: 10.2174/0929867323666160418114826] [Citation(s) in RCA: 130] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2016] [Revised: 04/04/2016] [Accepted: 04/15/2016] [Indexed: 12/17/2022]
Abstract
The development of reversibly binding radioligands for imaging brain proteins in vivo, such as enzymes, neurotransmitter transporters, receptors and ion channels, with positron emission tomography (PET) is keenly sought for biomedical studies of neuropsychiatric disorders and for drug discovery and development, but is recognized as being highly challenging at the medicinal chemistry level. This article aims to compile and discuss the main considerations to be taken into account by chemists embarking on programs of radioligand development for PET imaging of brain protein targets.
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Affiliation(s)
- Victor W Pike
- Molecular Imaging Branch, National Institute of Mental Health, National Institutes of Health, Rm. B3C346A, 10 Center Drive, Bethesda, MD 20892, USA.
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16
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Connors KA, Valenti TW, Lawless K, Sackerman J, Onaivi ES, Brooks BW, Gould GG. Similar anxiolytic effects of agonists targeting serotonin 5-HT1A or cannabinoid CB receptors on zebrafish behavior in novel environments. AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2014; 151:105-13. [PMID: 24411165 PMCID: PMC3989442 DOI: 10.1016/j.aquatox.2013.12.005] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/01/2013] [Revised: 11/30/2013] [Accepted: 12/05/2013] [Indexed: 05/15/2023]
Abstract
The discovery that selective serotonin reuptake inhibitors (SSRIs) such as fluoxetine are present and bioaccumulate in aquatic ecosystems have spurred studies of fish serotonin transporters (SERTs) and changes in SSRI-sensitive behaviors as adverse outcomes relevant for risk assessment. Many SSRIs also act at serotonin 5-HT1A receptors. Since capitalizing on this action may improve treatments of clinical depression and other psychiatric disorders, novel multimodal drugs that agonize 5-HT1A and block SERT were introduced. In mammals both 5-HT1A and CB agonists, such as buspirone and WIN55,212-2, reduce anxious behaviors. Immunological and behavioral evidence suggests that 5-HT1A-like receptors may function similarly in zebrafish (Danio rerio), yet their pharmacological properties are not well characterized. Herein we compared the density of [(3)H] 8-hydroxy-2-di-n-propylamino tetralin (8-OH-DPAT) binding to 5-HT1A-like sites in the zebrafish brain, to that of similarly Gαi/o-coupled cannabinoid receptors. [(3)H] 8-OH-DPAT specific binding was 176±8, 275±32, and 230±36fmol/mg protein in the hypothalamus, optic tectum, and telencephalon. [(3)H] WIN55,212-2 binding density was higher in those same brain regions at 6±0.3, 5.5±0.4 and 7.3±0.3pm/mg protein. The aquatic light-dark plus maze was used to examine behavioral effects of 5-HT1A and CB receptor agonists on zebrafish novelty-based anxiety. With acute exposure to the 5-HT1A partial-agonist buspirone (50mg/L), or dietary exposure to WIN55,212-2 (7μg/week) zebrafish spent more time in and/or entered white arms more often than controls (p<0.05). Acute exposure to WIN55,212-2 at 0.5-50mg/L reduced mobility. These behavioral findings suggest that azipirones, like cannabinoid agonists, have anxiolytic and/or sedative properties on fish in novel environments. These observations highlight the need to consider potential ecological risks of azapirones and multimodal antidepressants in the future.
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Affiliation(s)
- Kristin A Connors
- Department of Environmental Science, Institute of Biomedical Studies, Baylor University, Waco, TX 76798-7266, USA
| | - Theodore W Valenti
- Department of Environmental Science, The Institute of Ecological, Earth, and Environmental Science, Baylor University, Waco, TX 76798-7266, USA(1); Syngenta Crop Protection LLC, Greensboro, NC 27419, USA(2)
| | - Kelly Lawless
- Department of Biology, William Paterson University, Wayne, NJ 07470, USA
| | - James Sackerman
- Department of Biology, William Paterson University, Wayne, NJ 07470, USA
| | - Emmanuel S Onaivi
- Department of Biology, William Paterson University, Wayne, NJ 07470, USA
| | - Bryan W Brooks
- Department of Environmental Science, Institute of Biomedical Studies, Baylor University, Waco, TX 76798-7266, USA; Department of Environmental Science, The Institute of Ecological, Earth, and Environmental Science, Baylor University, Waco, TX 76798-7266, USA(1)
| | - Georgianna G Gould
- Department of Physiology and Center for Biomedical Neuroscience, The University of Texas Health Science Center at San Antonio, San Antonio, TX 78229-3900, USA.
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17
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Abstract
Serotonin (5-HT) and oxytocin (OXT) are two neuromodulators involved in human affect and sociality and in disorders like depression and autism. We asked whether these chemical messengers interact in the regulation of emotion-based behavior by administering OXT or placebo to 24 healthy subjects and mapping cerebral 5-HT system by using 2'-methoxyphenyl-(N-2'-pyridinyl)-p-[(18)F]fluoro-benzamidoethylpiperazine ([(18)F]MPPF), an antagonist of 5-HT1A receptors. OXT increased [(18)F]MPPF nondisplaceable binding potential (BPND) in the dorsal raphe nucleus (DRN), the core area of 5-HT synthesis, and in the amygdala/hippocampal complex, insula, and orbitofrontal cortex. Importantly, the amygdala appears central in the regulation of 5-HT by OXT: [(18)F]MPPF BPND changes in the DRN correlated with changes in right amygdala, which were in turn correlated with changes in hippocampus, insula, subgenual, and orbitofrontal cortex, a circuit implicated in the control of stress, mood, and social behaviors. OXT administration is known to inhibit amygdala activity and results in a decrease of anxiety, whereas high amygdala activity and 5-HT dysregulation have been associated with increased anxiety. The present study reveals a previously unidentified form of interaction between these two systems in the human brain, i.e., the role of OXT in the inhibitory regulation of 5-HT signaling, which could lead to novel therapeutic strategies for mental disorders.
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Farajian Mashhadi F, Naylor RJ, Javid FA. The Effects of Serotonin Receptor Antagonists on Contraction and Relaxation Responses Induced by Electrical Stimulation in the Rat Small Intestine. ACTA ACUST UNITED AC 2014. [DOI: 10.17795/gct-18311] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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19
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Majo VJ, Milak MS, Prabhakaran J, Mali P, Savenkova L, Simpson NR, Mann JJ, Parsey RV, Dileep Kumar JS. Synthesis and in vivo evaluation of [(18)F]2-(4-(4-(2-(2-fluoroethoxy)phenyl)piperazin-1-yl)butyl)-4-methyl-1,2,4-triazine-3,5(2H,4H)-dione ([(18)F]FECUMI-101) as an imaging probe for 5-HT1A receptor agonist in nonhuman primates. Bioorg Med Chem 2013; 21:5598-604. [PMID: 23816046 PMCID: PMC3858174 DOI: 10.1016/j.bmc.2013.05.050] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2013] [Revised: 05/09/2013] [Accepted: 05/17/2013] [Indexed: 10/26/2022]
Abstract
The 5-HT1AR partial agonist PET radiotracer, [(11)C]CUMI-101, has advantages over an antagonist radiotracer as it binds preferentially to the high affinity state of the receptor and thereby provides more functionally meaningful information. The major drawback of C-11 tracers is the lack of cyclotron facility in many health care centers thereby limiting widespread clinical or research use. We identified the fluoroethyl derivative, 2-(4-(4-(2-(2-fluoroethoxy)phenyl)piperazin-1-yl)butyl)-4-methyl-1,2,4-triazine-3,5(2H,4H)dione (FECUMI-101) (Ki=0.1nM; Emax=77%; EC50=0.65nM) as a partial agonist 5-HT1AR ligand of the parent ligand CUMI-101. FECUMI-101 is radiolabeled with F-18 by O-fluoroethylation of the corresponding desmethyl analogue (1) with [(18)F]fluoroethyltosylate in DMSO in the presence of 1.6equiv of K2CO3 in 45±5% yield (EOS). PET shows [(18)F]FECUMI-101 binds specifically to 5-HT1AR enriched brain regions of baboon. The specificity of [(18)F]FECUMI-101 binding to 5-HT1AR was confirmed by challenge studies with the known 5-HT1AR ligand WAY100635. These findings indicate that [(18)F]FECUMI-101 can be a viable agonist ligand for the in vivo quantification of high affinity 5-HT1AR with PET.
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Affiliation(s)
- Vattoly J. Majo
- Department of Psychiatry, Columbia University Medical Center, Columbia University, New York
| | - Matthew S. Milak
- Department of Psychiatry, Columbia University Medical Center, Columbia University, New York
- Division of Molecular Imaging and Neuropathology, New York State Psychiatric Institute, New York
| | - Jaya Prabhakaran
- Department of Psychiatry, Columbia University Medical Center, Columbia University, New York
| | - Pratap Mali
- Division of Molecular Imaging and Neuropathology, New York State Psychiatric Institute, New York
| | - Lyudmila Savenkova
- Department of Psychiatry, Columbia University Medical Center, Columbia University, New York
| | - Norman R. Simpson
- Division of Molecular Imaging and Neuropathology, New York State Psychiatric Institute, New York
| | - J. John Mann
- Department of Psychiatry, Columbia University Medical Center, Columbia University, New York
- Division of Molecular Imaging and Neuropathology, New York State Psychiatric Institute, New York
- Department of Radiology, Columbia University, New York, NY 10032
| | - Ramin V. Parsey
- Department of Psychiatry and Behavioral Science, Stony Brook University, New York
| | - J. S. Dileep Kumar
- Department of Psychiatry, Columbia University Medical Center, Columbia University, New York
- Division of Molecular Imaging and Neuropathology, New York State Psychiatric Institute, New York
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20
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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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Kumar JSD, Milak MS, Majo VJ, Prabhakaran J, Mali P, Savenkova L, Mann JJ, Parsey RV. Comparison of high and low affinity serotonin 1A receptors by PET in vivo in nonhuman primates. J Pharmacol Sci 2012; 120:254-7. [PMID: 23076129 DOI: 10.1254/jphs.12100sc] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022] Open
Abstract
Serotonin (5-HT) 1A receptors exist in high and low affinity states. Agonist ligands bind preferentially to the high affinity state receptors, providing a more functionally relevant measure than antagonist binding. We now report comparison of 5-HT(1A) binding in vivo using both [¹¹C]CUMI-101 (agonist) and [¹¹C]WAY100635 (antagonist) in nonhuman primates. PET studies show that both tracers bind to known 5-HT(1A) receptor (5-HT(1A)R)-rich regions of baboon brain. The binding (BP(F)) of [¹¹C]CUMI-101 was lower on an average of 55% across the regions of interest (ROIs) compared to [¹¹C]WAY100635. This ratio is consistent with the in vitro binding data of agonist and antagonist 5-HT(1A)R ligands previously reported.
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Affiliation(s)
- J S Dileep Kumar
- Division of Molecular Imaging and Neuropathology, Department of Psychiatry, Columbia University College of Physicians and Surgeons, New York, NY 10032, USA.
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22
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Eleventh international symposium on radiopharmaceutical chemistry: Abstracts. J Labelled Comp Radiopharm 2012. [DOI: 10.1002/jlcr.2580370301] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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23
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Frankle WG, Lombardo I, Kegeles LS, Slifstein M, Martin JH, Huang Y, Hwang DR, Reich E, Cangiano C, Gil R, Abi-Dargham A, Laruelle M. Measurement of the serotonin 1A receptor availability in patients with schizophrenia during treatment with the antipsychotic medication ziprasidone. J Psychopharmacol 2011; 25:734-43. [PMID: 21109614 DOI: 10.1177/0269881110388329] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The aim of this study was to compare 5-HT(1A) availability in vivo in individuals with schizophrenia before and during treatment with the atypical antipsychotic ziprasidone. Six individuals with schizophrenia underwent two PET scans with [(11)C]WAY 100635; the first while medication-free (baseline) and the second while taking the atypical antipsychotic ziprasidone (on-medication). Regional volumes of distribution (V(T), mL g(-1)) were derived using a two-tissue compartment kinetic model. Outcome measures included binding potential relative to the plasma (BP(P), mL g(-1)) and the binding potential relative to the nonspecific distribution volume (BP(ND), unitless). No significant differences were observed in regional BP(P) or BP(ND) with ziprasidone treatment. A significant correlation was noted between BP(P) measured in the orbitofrontal cortex during the on-medication condition and degree of improvement in negative symptoms with treatment (r = 0.96, p = 0.004). Consistent with the published literature of changes in 5-HT(1A) binding during treatment with 5-HT(1A) receptor agonists, this study did not detect a significant reduction in 5-HT(1A) binding with ziprasidone. The finding of a relationship between 5-HT(1A) binding and the degree of improvement in negative symptoms provides further support for the role of the 5-HT(1A) receptor in the pathophysiology and treatment of this symptom domain.
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Affiliation(s)
- W Gordon Frankle
- Department of Psychiatry, Columbia University College of Physicians and Surgeons, New York, USA.
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Pineda EA, Hensler JG, Sankar R, Shin D, Burke TF, Mazarati AM. Plasticity of presynaptic and postsynaptic serotonin 1A receptors in an animal model of epilepsy-associated depression. Neuropsychopharmacology 2011; 36:1305-16. [PMID: 21346733 PMCID: PMC3077437 DOI: 10.1038/npp.2011.18] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Depression is a common comorbidity of temporal lobe epilepsy and has highly negative impact on patients' quality of life. We previously established that pilocarpine-induced status epilepticus (SE) in rats, concurrently with chronic epilepsy leads to depressive impairments, and that the latter may stem from the dysregulation of hypothalamo-pituitary-adrenocortical (HPA) axis and/or diminished raphe-hippocampal serotonergic transmission. We examined possible involvement of presynaptic and postsynaptic serotonin 1A (5-HT1A) receptors in epilepsy-associated depression. Based on their performance in the forced swim test (FST), post-SE animals were classified as those with moderate and severe depressive impairments. In moderately impaired rats, the activity of the HPA axis (examined using plasma corticosterone radioimmunoassay) was higher than in naive subjects, but the functional capacity of presynaptic 5-HT1A receptors (measured in raphe using autoradiography) remained unaltered. In severely depressed animals, both the activity of the HPA axis and the function of presynaptic 5-HT1A receptors were increased as compared with naive and moderately depressed rats. Pharmacological uncoupling of the HPA axis from raphe nucleus exerted antidepressant effects in severely impaired rats, but did not modify behavior in both naive and moderately depressed animals. Further, the function of postsynaptic 5-HT1A receptors was diminished in the hippocampus of post-SE rats. Pharmacological activation of postsynaptic 5-HT1A receptors improved depressive deficits in epileptic animals. We suggest that under the conditions of chronic epilepsy, excessively hyperactive HPA axis activates presynaptic 5-HT1A receptors, thus shifting the regulation of serotonin release in favor of autoinhibition. Downregulation of postsynaptic 5-HT1A receptors may further exacerbate the severity of epilepsy-associated depression.
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Affiliation(s)
- Eduardo A Pineda
- Department of Pediatrics, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA, USA
| | - Julie G Hensler
- Department of Pharmacology, University of Texas Health Science Center-San Antonio, San Antonio, TX, USA
| | - Raman Sankar
- Department of Pediatrics, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA, USA
| | - Don Shin
- Department of Pediatrics, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA, USA
| | - Teresa F Burke
- Department of Pharmacology, University of Texas Health Science Center-San Antonio, San Antonio, TX, USA
| | - Andréy M Mazarati
- Department of Pediatrics, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA, USA,Department of Pediatrics, Neurology Division, David Geffen School of Medicine at UCLA, Box 951752, 22-474 MDCC, Los Angeles, CA 90095-1752, USA, Tel: +1 310 206 5198, Fax: +1 310 825 5834, E-mail:
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Palner M, Underwood MD, Kumar DJS, Arango V, Knudsen GM, John Mann J, Parsey RV. Ex vivo evaluation of the serotonin 1A receptor partial agonist [³H]CUMI-101 in awake rats. Synapse 2011; 65:715-23. [PMID: 21108237 DOI: 10.1002/syn.20888] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2010] [Accepted: 11/11/2010] [Indexed: 11/11/2022]
Abstract
[³H]CUMI-101 is a 5-HT(1A) partial agonist, which has been evaluated for use as a positron emission tracer in baboon and humans. We sought to evaluate the properties of [³H]CUMI-101 ex vivo in awake rats and determine if [³H]CUMI-101 can measure changes in synaptic levels of serotonin after different challenge paradigms. [³H]CUMI-101 shows good uptake and good specific binding ratio (SBR) in frontal cortex 5.18 and in hippocampus 3.18. Binding was inhibited in a one-binding-site fashion by WAY100635 and unlabeled CUMI-101. The ex vivo B(max) of [³H]CUMI-101 in frontal cortex (98.7 fmol/mg) and hippocampus (131 fmol/kg) agree with the ex vivo B(max) of [³H]MPPF in frontal cortex (147.1 fmol/mg) and hippocampus (72.1 fmol/mg) and with in vitro values reported with 8-OH-DPAT. Challenges with citalopram, a selective serotonin reuptake inhibitor, fenfluramine, a serotonin releaser, and 4-chloro-DL-phenylalanine, a serotonin synthesis inhibitor, did not show any effect on the standardized uptake values (SUVs) in any region. Citalopram did alter SBR, but this was due to changes in cerebellar SUVs. Our results indicate that [³H]CUMI-101 is a good radioligand for imaging 5-HT(1A) high-density regions in rats; however, the results from pharmacological challenges remain inconclusive.
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Affiliation(s)
- Mikael Palner
- Division of Molecular Imaging and Neuropathology, New York State Psychiatric Institute, New York, New York, USA.
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Hendry N, Christie I, Rabiner EA, Laruelle M, Watson J. In vitro assessment of the agonist properties of the novel 5-HT1A receptor ligand, CUMI-101 (MMP), in rat brain tissue. Nucl Med Biol 2010; 38:273-7. [PMID: 21315283 DOI: 10.1016/j.nucmedbio.2010.08.003] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2010] [Revised: 07/31/2010] [Accepted: 08/11/2010] [Indexed: 11/19/2022]
Abstract
INTRODUCTION Development of agonist positron emission tomography (PET) radioligands for the 5-HT neurotransmitter system is an important target to enable the understanding of human 5-HT function in vivo. [(11)C]CUMI-101, proposed as the first 5-HT(1A) receptor agonist PET ligand, has been reported to behave as a potent 5-HT(1A) agonist in a cellular system stably expressing human recombinant 5-HT(1A) receptors. In this study, we investigate the agonist properties of CUMI-101 in rat brain tissue. METHODS [(35)S]-GTPγS binding studies were used to determine receptor function in HEK (human embryonic kidney) 293 cells transfected with human recombinant 5-HT(1A) receptors and in rat cortex and rat hippocampal tissue, following administration of CUMI-101 and standard 5-HT1A antagonists (5-HT, 5-CT and 8-OH-DPAT). RESULTS CUMI-101 behaved as an agonist at human recombinant 5-HT(1A) receptors (pEC(50) 9.2). However, CUMI-101 did not show agonist activity in either rat cortex or hippocampus at concentrations up to 10 μM. In these tissues, CUMI-behaved as an antagonist with pK(B)s of 9.2 and 9.3, respectively. CONCLUSIONS Our studies demonstrate that as opposed to its behavior in human recombinant system, in rat brain tissue CUMI-101 behaves as a potent 5-HT(1A) receptor antagonist.
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Affiliation(s)
- Nicola Hendry
- Neurosciences Centre of Excellence for Drug Discovery, GlaxoSmithKline, Harlow, CM19 5AW Essex, UK
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Millimolar Mn2+ influences agonist binding to 5-HT1A receptors by inhibiting guanosine nucleotide binding to receptor-coupled G-proteins. Neurotoxicology 2010; 32:25-30. [PMID: 21126535 DOI: 10.1016/j.neuro.2010.11.005] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2010] [Revised: 11/12/2010] [Accepted: 11/23/2010] [Indexed: 12/16/2022]
Abstract
Manganese is an essential trace element but its overexposure causes poisoning (called manganism) that shares several symptoms with Parkinson's disease, but with a mechanism that is still not well understood: in addition to involvement of the dopaminergic system, both serotonergic and peptiergic systems have been implicated. In the present report we have studied the influence of Mn(2+) on 5-HT(1A) receptor signaling complexes in rat brain and found that Mn(2+) in millimolar concentration caused an increase of high-affinity agonist binding to rat hippocampal membranes in comparison with experiments in the presence of Mg(2+), but not in rat cortical membranes and in Sf9 cell membranes expressing 5-HT(1A) receptors and G(i1) heterotrimers. Activation of G proteins with 30μM GTPγS turned all 5-HT(1A) receptors in these preparations into a low-affinity state for agonist binding in the presence of 1mM Mg(2+), but not in the presence of 1mM Mn(2+) in rat hippocampal membranes. However, if 1μM GTPγS was used for G protein activation, a substantial amount of high affinity agonist binding was detected in the presence of Mn(2+) also in cortical membranes and Sf9 cells, but not with Mg(2+) or EDTA. Comparison of the abilities of GDP and GTPγS to modulate high affinity agonist binding to 5-HT(1A) receptors indicated that both nucleotides were almost 10-fold less potent in the presence of MnCl(2) compared to MgCl(2). This means that by inhibiting guanosine nucleotide binding to G proteins in complex with 5-HT(1A) receptors, Mn(2+) acts as an enhancer for agonist binding and signal transduction. As the influence of Mn(2+) resembles the hypersensitivity of dopaminergic system in Parkinsonial models, it can be proposed that at least some symptoms of manganism are connected with a change of signal transduction complex caused by manganese-nucleotide complexes.
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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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[3H]-F13640, a novel, selective and high-efficacy serotonin 5-HT1A receptor agonist radioligand. Naunyn Schmiedebergs Arch Pharmacol 2010; 382:321-30. [DOI: 10.1007/s00210-010-0551-4] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2010] [Accepted: 08/10/2010] [Indexed: 11/25/2022]
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Parsey RV, Ogden RT, Miller JM, Tin A, Hesselgrave N, Goldstein E, Mikhno A, Milak M, Zanderigo F, Sullivan GM, Oquendo MA, Mann JJ. Higher serotonin 1A binding in a second major depression cohort: modeling and reference region considerations. Biol Psychiatry 2010; 68:170-8. [PMID: 20497898 PMCID: PMC2900398 DOI: 10.1016/j.biopsych.2010.03.023] [Citation(s) in RCA: 131] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/05/2009] [Revised: 02/24/2010] [Accepted: 03/02/2010] [Indexed: 11/23/2022]
Abstract
BACKGROUND Serotonin 1A receptors (5-HT(1A)) are implicated in major depressive disorder (MDD). We previously reported higher 5-HT(1A) binding potential (BP(F)) in antidepressant naive MDD subjects compared with control subjects, while other studies report lower BP(ND). Discrepancies can be related to differences in study population or methodology. We sought to replicate our findings in a novel cohort and determine whether choice of reference region and outcome measure could explain discrepancies. METHODS Nine new control subjects and 22 new not recently medicated (NRM) MDD subjects underwent positron emission tomography. BP(F) and BP(ND) were determined using a metabolite and free fraction corrected arterial input function. BP(ND) was also determined using cerebellar gray matter (CGM) and cerebellar white matter (CWM) reference regions as input functions. RESULTS BP(F) was higher in the new NRM cohort (p = .037) compared with new control subjects, comparable to the previous cohort (p = .04). Cohorts were combined to examine the reference region and outcome measure. BP(F) was higher in the NRM compared with control subjects (p = .0001). Neither BP(ND) using CWM (p = .86) nor volume of distribution (V(T)) (p = .374) differed between groups. When CGM was used, the NRM group had lower 5-HT(1A) BP(ND) compared with control subjects (p = .03); CGM V(T) was higher in NRM compared with control subjects (p = .007). CONCLUSIONS Choice of reference region and outcome measure can produce different 5-HT(1A) findings. Higher 5-HT(1A) BP(F) in MDD was found with the method with fewest assumptions about nonspecific binding and a reference region without receptors.
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Affiliation(s)
- Ramin V Parsey
- Department of Psychiatry, Columbia University College of Physicians and Surgeons, New York, New York 10032, USA.
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Lothe A, Boni C, Costes N, Bouvard S, Gorwood P, Lavenne F, Alvarez M, Ryvlin P. 5-HT1A gene promoter polymorphism and [18F]MPPF binding potential in healthy subjects: a PET study. Behav Brain Funct 2010; 6:37. [PMID: 20609217 PMCID: PMC2909987 DOI: 10.1186/1744-9081-6-37] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2010] [Accepted: 07/07/2010] [Indexed: 11/21/2022] Open
Abstract
Background Previous Positron Emission Tomography (PET) studies of 5-HT1A receptors have shown an influence of several genetic factors, including the triallelic serotonin transporter gene-linked polymorphic region on the binding potential (BPND) of these receptors. The aim of our study was to investigate the relationship between a 5-HT1A promoter polymorphism and the binding potential of another selective 5-HT1A receptor antagonist, [18F]MPPF, in healthy subjects. Methods Thirty-five volunteers, including 23 women, underwent an [18F]MPPF scan and were genotyped for both the C(-1019)G 5-HT1A promoter polymorphism and the triallelic serotonin transporter gene-linked polymorphic region. We used a simplified reference tissue model to generate parametric images of BPND. Whole brain Statistical Parametric Mapping and raphe nuclei region of interest analyses were performed to look for an association of [18F]MPPF BPND with the C(-1019)G 5-HT1A promoter polymorphism. Results Among the 35 subjects, 5-HT1A promoter genotypes occurred with the following frequencies: three G/G, twenty-one G/C, and eleven C/C. No difference of [18F]MPPF BPND between groups was observed, except for two women who were homozygote carriers for the G allele and showed greater binding potential compared to other age-matched women over the frontal and temporal neocortex. However, the biological relevance of this result remains uncertain due to the very small number of subjects with a G/G genotype. These findings were not modified by excluding individuals carrying the S/S genotype of the serotonin transporter gene-linked polymorphic region. Conclusions We failed to observe an association between the C(-1019)G 5-HT1A promoter polymorphism and [18F]MPPF binding in healthy subjects. However our data suggest that the small number of women homozygote for the G allele might have greater [18F]MPPF BPND relative to other individuals. This finding should be confirmed in a larger sample.
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Effect of electroconvulsive therapy on 5-HT1A receptor binding in patients with depression: a PET study with [11C]WAY 100635. Int J Neuropsychopharmacol 2010; 13:785-91. [PMID: 20067660 DOI: 10.1017/s1461145709991209] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
In our previous positron emission tomography (PET) study, we demonstrated that ECT decreased dopamine D2 receptor in major depressive disorder (MDD). Although many animal studies have focused on the effect of ECT on serotonergic neurotransmission, no human study has directly examined the effect of ECT on brain serotonin [5-hydroxytryptamine (5-HT)] 1A receptors (5-HT1ARs). Using PET with [11C]WAY 100635, we aimed to evaluate the effect of ECT on 5-HT1ARs in patients with MDD. Nine patients underwent PET scans before and after a series of 6-7 bilateral ECTs. Region-of-interest analysis was performed based on the simplified reference tissue model. There were no significant changes in 5-HT1AR binding in patients between before and after ECT. ECT did not alter [11C]WAY 100635 binding even after recovery from depressive episode. Although the present finding does not exclude the involvement of brain 5-HT1A systems in the antidepressant action of ECT, it may indicate the involvement of other neurotransmission mechanisms.
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Benninghoff J, Gritti A, Rizzi M, Lamorte G, Schloesser RJ, Schmitt A, Robel S, Genius J, Moessner R, Riederer P, Manji HK, Grunze H, Rujescu D, Moeller HJ, Lesch KP, Vescovi AL. Serotonin depletion hampers survival and proliferation in neurospheres derived from adult neural stem cells. Neuropsychopharmacology 2010; 35:893-903. [PMID: 20010549 PMCID: PMC3055363 DOI: 10.1038/npp.2009.181] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Serotonin (5-HT) and the serotonergic system have recently been indicated as modulators of adult hippocampal neurogenesis. In this study, we evaluated the role of 5-HT on the functional features in neurospheres derived from adult neural stem cells (ANSC). We cultured neurospheres derived from mouse hippocampus in serum-free medium containing epidermal (EGF) and type-2 fibroblast growth factor (FGF2). Under these conditions ANSC expressed both isoforms of tryptophane-hydroxylase (TPH) and produced 5-HT. Blocking TPH function by para-chlorophenylalanine (PCPA) reduced ANSC proliferation, which was rescued by exogenous 5-HT. 5-HT action on ANSC was mediated predominantly by the serotonin receptor subtype 5-HT1A and, to a lesser extent, through the 5-HT2C (receptor) subtype, as shown by selectively antagonizing these receptors. Finally, we documented a 5-HT-induced increase of ANSC migration activity. In summary, we demonstrated a powerful serotonergic impact on ANSC functional features, which was mainly mediated by 5-HT1A receptors.
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Affiliation(s)
- Jens Benninghoff
- S. Raffaele Scientific Institute, Stem Cell Research Institute (HSR-SCRI), Milan, Italy.
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Mengod G, Cortés R, Vilaró MT, Hoyer D. Distribution of 5-HT Receptors in the Central Nervous System. HANDBOOK OF BEHAVIORAL NEUROSCIENCE 2010. [DOI: 10.1016/s1569-7339(10)70074-6] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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Antagonist but not agonist labeling of serotonin-1A receptors is decreased in major depressive disorder. J Psychiatr Res 2009; 43:887-94. [PMID: 19215942 PMCID: PMC2754145 DOI: 10.1016/j.jpsychires.2009.01.001] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/25/2008] [Revised: 12/22/2008] [Accepted: 01/12/2009] [Indexed: 11/22/2022]
Abstract
Serotonin-1A receptors may play a role in the pathophysiology of depression and suicide. In postmortem brain tissue, agonist binding to serotonin-1A receptors is reportedly increased or unchanged in depression or suicide, while neuroimaging studies report a decrease in antagonist binding to these receptors in subjects with depression. In this study, both agonist and antagonist radioligand binding to serotonin-1A receptors were examined in postmortem orbitofrontal cortex from subjects with major depressive disorder (MDD). Brain tissue was collected at autopsy from 11 subjects with MDD and 11 age- and gender-matched normal control subjects. Two depressed subjects had a recent psychoactive substance use disorder. Six subjects with MDD had a prescription for an antidepressant drug in the last month of life, and, of these six, postmortem bloods from only two subjects tested positive for an antidepressant drug. There was no significant difference between cohorts for age, postmortem interval or tissue pH. The receptor agonist [3H]8-OH-DPAT or the antagonist [3H]MPPF were used to autoradiographically label serotonin-1A receptors in frozen sections from cytoarchitectonically-defined left rostral orbitofrontal cortex (area 47). There was no significant difference between depressed and control subjects in agonist binding to serotonin-1A receptors. However, antagonist binding was significantly decreased in outer layers of orbitofrontal cortex in MDD. This observation in postmortem tissue confirms reports using an antagonist radioligand in living subjects with depression. Decreased antagonist binding to serotonin-1A receptors in outer layers of orbitofrontal cortex suggests diminished receptor signaling and may be linked to corresponding neuronal changes detected previously in these depressed subjects.
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Winter JC. Hallucinogens as discriminative stimuli in animals: LSD, phenethylamines, and tryptamines. Psychopharmacology (Berl) 2009; 203:251-63. [PMID: 18979087 DOI: 10.1007/s00213-008-1356-8] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/03/2008] [Accepted: 09/24/2008] [Indexed: 12/24/2022]
Abstract
BACKGROUND Although man's first encounters with hallucinogens predate written history, it was not until the rise of the sister disciplines of organic chemistry and pharmacology in the nineteenth century that scientific studies became possible. Mescaline was the first to be isolated and its chemical structure determined. Since then, additional drugs have been recovered from their natural sources and synthetic chemists have contributed many more. Given their profound effects upon human behavior and the need for verbal communication to access many of these effects, some see humans as ideal subjects for study of hallucinogens. However, if we are to determine the mechanisms of action of these agents, establish hypotheses testable in human subjects, and explore the mechanistic links between hallucinogens and such apparently disparate topics as idiopathic psychosis, transcendental states, drug abuse, stress disorders, and cognitive dysfunction, studies in animals are essential. Stimulus control by hallucinogens has provided an intuitively attractive approach to the study of these agents in nonverbal species. OBJECTIVE The intent of this review is to provide a brief account of events from the time of the first demonstration of hallucinogen-induced stimulus control to the present. In general, the review is limited to lysergic acid diethylamide (LSD) and the hallucinogenic derivatives of phenethylamine and tryptamine. RESULTS The pharmacological basis for stimulus control by LSD and hallucinogenic phenethylamines and tryptamines is serotonergic in nature. The 5-HT(2A) receptor appears to be the primary site of action with significant modulation by other serotonergic sites including 5-HT(2C) and 5-HT(1A) receptors. Interactions with other neurotransmitters, especially glutamate and dopamine, are under active investigation. Most studies to date have been conducted in the rat but transgenic mice offer interesting possibilities. CONCLUSIONS Hallucinogen-induced stimulus control provides a unique behavioral tool for the prediction of subjective effects in man and for the elucidation of the pharmacological mechanisms of the action of these agents.
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Affiliation(s)
- J C Winter
- Department of Pharmacology and Toxicology, School of Medicine and Biomedical Sciences, State University of New York at Buffalo, 102 Farber Hall, Buffalo, NY 14214-3000, USA.
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Brenchat A, Romero L, García M, Pujol M, Burgueño J, Torrens A, Hamon M, Baeyens JM, Buschmann H, Zamanillo D, Vela JM. 5-HT7 receptor activation inhibits mechanical hypersensitivity secondary to capsaicin sensitization in mice. Pain 2008; 141:239-247. [PMID: 19118950 DOI: 10.1016/j.pain.2008.11.009] [Citation(s) in RCA: 109] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2008] [Revised: 10/20/2008] [Accepted: 11/10/2008] [Indexed: 12/13/2022]
Abstract
This work aimed to evaluate the potential role of the 5-HT(7) receptor in nociception secondary to a sensitizing stimulus in mice. For this purpose, the effects of relevant ligands (5-HT(7) receptor agonists: AS-19, MSD-5a, E-55888; 5-HT(7) receptor antagonists: SB-258719, SB-269970; 5-HT(1A) receptor agonist: F-13640; 5-HT(1A) receptor antagonist: WAY-100635) were assessed on capsaicin-induced mechanical hypersensitivity, a pain behavior involving hypersensitivity of dorsal horn neurons (central sensitization). For the 5-HT(7) receptor agonists used, binding profile and intrinsic efficacy to stimulate cAMP formation in HEK-293F cells expressing the human 5-HT(7) receptor were also evaluated. AS-19 and E-55888 were selective for 5-HT(7) receptors. E-55888 was a full agonist whereas AS-19 and MSD-5a behaved as partial agonists, with maximal effects corresponding to 77% and 61%, respectively, of the cAMP response evoked by the full agonist 5-HT. Our in vivo results revealed that systemic administration of 5-HT(7) receptor agonists exerted a clear-cut dose-dependent antinociceptive effect that was prevented by 5-HT(7) receptor antagonists, but not by the 5-HT(1A) receptor antagonist. The order of efficacy (E-55888>AS-19>MSD-5a) matched their in vitro efficacy as 5-HT(7) receptor agonists. Contrary to agonists, a dose-dependent promotion of mechanical hypersensitivity was observed after administration of 5-HT(7) receptor antagonists, substantiating the involvement of the 5-HT(7) receptor in the control of capsaicin-induced mechanical hypersensitivity. These findings suggest that serotonin exerts an inhibitory role in the control of nociception through activation of 5-HT(7) receptors, and point to a new potential therapeutic use of 5-HT(7) receptor agonists in the field of analgesia.
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Affiliation(s)
- Alex Brenchat
- Laboratorios Esteve, Department of Pharmacology, Av. Mare de Déu de Montserrat, 221, 08041 Barcelona, Spain UMR 677 INSERM/UPMC, Faculté de Médecine Pierre et Marie Curie, Site Pitié-Salpêtrière, 91 Boulevard de l'hôpital, 75634 Paris Cedex 13, France Departmento de Farmacología e Instituto de Neurociencias, Facultad de Medicina, Universidad de Granada, Av. de Madrid, 11, 18012 Granada, Spain
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MicroPET imaging of 5-HT 1A receptors in rat brain: a test-retest [18F]MPPF study. Eur J Nucl Med Mol Imaging 2008; 36:53-62. [PMID: 18704404 DOI: 10.1007/s00259-008-0891-1] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2008] [Accepted: 07/11/2008] [Indexed: 10/21/2022]
Abstract
PURPOSE Earlier studies have shown that positron emission tomography (PET) imaging with the radioligand [(18)F]MPPF allows for measuring the binding potential of serotonin 5-hydroxytryptamine(1A) (5-HT(1A)) receptors in different regions of animal and human brain, including that of 5-HT(1A) autoreceptors in the raphe nuclei. In the present study, we sought to determine if such data could be obtained in rat, with a microPET (R4, Concorde Microsystems). METHODS Scans from isoflurane-anaesthetised rats (n = 18, including six test-retest) were co-registered with magnetic resonance imaging data, and binding potential, blood to plasma ratio and radiotracer efflux were estimated according to a simplified reference tissue model. RESULTS Values of binding potential for hippocampus (1.2), entorhinal cortex (1.1), septum (1.1), medial prefrontal cortex (1.0), amygdala (0.8), raphe nuclei (0.6), paraventricular hypothalamic nucleus (0.5) and raphe obscurus (0.5) were comparable to those previously measured with PET in cats, non-human primates or humans. Test-retest variability was in the order of 10% in the larger brain regions (hippocampus, medial prefrontal and entorhinal cortex) and less than 20% in small nuclei such as the septum and the paraventricular hypothalamic, basolateral amygdaloid and raphe nuclei. CONCLUSIONS MicroPET brain imaging of 5-HT(1A) receptors with [(18)F]MPPF thus represents a promising avenue for investigating 5-HT(1A) receptor function in rat.
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Sibon I, Benkelfat C, Gravel P, Aznavour N, Costes N, Mzengeza S, Booij L, Baker G, Soucy JP, Zimmer L, Descarries L. Decreased [18F]MPPF binding potential in the dorsal raphe nucleus after a single oral dose of fluoxetine: a positron-emission tomography study in healthy volunteers. Biol Psychiatry 2008; 63:1135-40. [PMID: 18191817 DOI: 10.1016/j.biopsych.2007.11.016] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/27/2007] [Revised: 11/01/2007] [Accepted: 11/27/2007] [Indexed: 11/28/2022]
Abstract
BACKGROUND Brain serotonin-1A (5-HT(1A)) autoreceptors internalize when activated by agonist or by their endogenous ligand, serotonin. This positron-emission tomography (PET) study tested the hypothesis that 5-HT(1A) autoreceptor internalization might be indexed in vivo by a decrease in the specific binding of the 5-HT(1A) radioligand, 4-[18F]fluoro-N-[2-[1-(2-methoxyphenyl)-1 piperazinyl]ethyl-N-2-pyridinyl-benzamide ([(18)F]MPPF), in the dorsal raphe nucleus (DRN) of healthy adult men administered a single oral dose of the selective serotonin reuptake inhibitor, fluoxetine. METHODS [(18)F]MPPF binding potential was measured in the DRN and other brain regions endowed with 5-HT(1A) receptors in eight healthy volunteers, 5 hours after the randomized, double-blind administration of fluoxetine (20 mg) or placebo. RESULTS In every subject, [(18)F]MPPF binding potential was decreased in the DRN only (44% +/- 22 SD), in response to fluoxetine. CONCLUSIONS Imaging the functional state of 5-HT(1A) autoreceptors (i.e., internalization) in the human brain, using [(18)F]MPPF/PET, may represent a promising avenue for investigating the neurobiology of serotonin-related disorders and notably of major depression.
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Affiliation(s)
- Igor Sibon
- Department of Psychiatry, McGill University, Montreal, Quebec, Canada
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Majo VJ, Parsey RV, Prabhakaran J, Mann JJ, Dileep Kumar JS. Synthesis and evaluation of [O-methyl-11C]4-[3-[4-(2-methoxyphenyl)- piperazin-1-yl]propoxy]-4-aza-tricyclo[5.2.1.02,6]dec-8-ene-3,5-dione as a 5-HT1A receptor agonist PET ligand. J Labelled Comp Radiopharm 2008. [DOI: 10.1002/jlcr.1475] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Hensler JG, Advani T, Monteggia LM. Regulation of serotonin-1A receptor function in inducible brain-derived neurotrophic factor knockout mice after administration of corticosterone. Biol Psychiatry 2007; 62:521-9. [PMID: 17336942 DOI: 10.1016/j.biopsych.2006.10.015] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/18/2006] [Revised: 09/19/2006] [Accepted: 10/12/2006] [Indexed: 11/24/2022]
Abstract
BACKGROUND We examined the effects of a forebrain-specific reduction in brain-derived neurotrophic factor (BDNF) on the regulation of serotonin-1A (5-HT1A) receptor function in serotonergic cell body areas as well as in limbic and cortical structures of mice chronically treated with corticosterone. METHODS 5-HT1A receptor function, at the level of receptor-G protein interaction, was assessed with quantitative autoradiography of [35S]GTPgammaS binding stimulated by the 5-HT1A receptor agonist 8-OH-DPAT. 5-HT1A receptor number was assessed by measuring the binding of the antagonist radioligand [3H] WAY100635. RESULTS We observed a significant attenuation of 5-HT1A receptor function, in the absence of a change in receptor number, in the dorsal hippocampus of BDNF knockout versus control mice. There was no difference between control and BDNF knockout mice in 5-HT1A receptor number or function in the dorsal or median raphe nuclei or medial prefrontal cortex or anterior cingulate cortex. Corticosterone treatment of control mice decreased 5-HT1A receptor function in the dorsal and median raphe but not in hippocampus or frontal cortical areas. The regulation of 5HT1A receptor number or function in the dorsal and median raphe by corticosterone was lost in BDNF knockout mice. CONCLUSIONS Attenuation of BDNF expression in forebrain regions produces differential effects on distinct 5-HT1A receptor populations and on the regulation of these receptor populations by corticosterone.
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Affiliation(s)
- Julie G Hensler
- Department of Pharmacology, University of Texas Health Science Center, San Antonio, Texas 78229-3900, USA.
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Abstract
The serotonin 5-HT(1A) receptor is implicated in the pathophysiology of major neuropsychiatric disorders, including depression, suicidal behavior, panic disorder, epilepsy, bulimia, schizophrenia, Parkinson's disease, and Alzheimer's disease and is, therefore, an important target for drug therapy. 5-HT(1A) receptors are expressed as somatodendritic autoreceptors in serotonin neurons of the raphé nuclei (presynaptic) and as postsynaptic receptors in cortical and subcortical serotonin terminal fields in the brain. Due to the higher concentration and heterogeneous distribution of this receptor, it is an attractive target for quantification in vivo using positron emission tomography (PET) and single photon emission tomography (SPECT). Here, we review the PET radioligands employed for imaging 5-HT(1A) receptors in living brain.
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Affiliation(s)
- J S Dileep Kumar
- Department of Psychiatry, Columbia University College of Physicians and Surgeons & New York State Psychiatric Institute, New York, NY 10032, United States.
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Giannaccini G, Betti L, Pirone A, Palego L, Fabiani O, Fabbrini L, Mascia G, Giusti L, Macchia M, Giusiani M, Martini C, Lucacchini A. Short-term effects of 3,4-methylen-dioxy-metamphetamine (MDMA) on 5-HT(1A) receptors in the rat hippocampus. Neurochem Int 2007; 51:496-506. [PMID: 17602794 DOI: 10.1016/j.neuint.2007.05.010] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2007] [Accepted: 05/11/2007] [Indexed: 11/30/2022]
Abstract
The first effects of 3,4-methylen-dioxy-metamphetamine (MDMA, "ecstasy"), on serotonin 1A (5-HT(1A)) receptors in rat hippocampus were determined by means of [(3)H]-8-hydroxy-dipropylamino-tetralin ([(3)H]-8-OH-DPAT) and 5'guanosine-(gamma-[(35)S]-thio)triphosphate ([(35)S]-GTPgammaS) binding as well as inhibition of forskolin (FK)-stimulated adenylyl cyclase (AC) activity. The study was completed by [(35)S]-GTPgammaS functional autoradiography experiments carried out in frontal sections of rat brain, including the hippocampal region. Results showed that MDMA was either able to displace [(3)H]-8-OH-DPAT binding (K(i) congruent with 500 nM) or to reduce the number of specific sites (B(max)) without affecting K(d). The drug also failed to change the [(35)S]-GTPgammaS binding or to inhibit AC velocity, underlying its behavior as a non-competitive 5-HT(1A) receptor antagonist. Further, MDMA (1 or 100 microM), partially antagonized either [(35)S]-GTPgammaS binding stimulation of the agonists 5CT and 8-OH-DPAT or the AC inhibition induced by 5CT and DP-5CT. However, in contrast to binding studies, in AC assays the amphetamine displayed an effect also on EC(50), always being less potent than the reference antagonist WAY100,635. In functional autoradiography, MDMA behaved either as a partial 5-HT(1A) antagonist in limbic areas or, added alone, as an agonist, increasing the coupling signal presumably through 5-HT release from synapses. Interestingly, the selective 5-HT re-uptake inhibitor (SSRI) fluoxetine had no effect on MDMA [(35)S]-GTPgammaS binding activation. This latter finding indicates that the amphetamine can release 5-HT via alternative mechanisms to 5-HT transporter binding, probably via membrane synaptic receptors or vesicular transporters. The release of other transmitters is not excluded. Therefore, our results encourage at extending the study of MDMA biochemical profiles, in the attempt to elucidate those amphetamine-induced pathways with a potential for neurotoxicity or psycho-stimulant activity.
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Affiliation(s)
- Gino Giannaccini
- Department of Psychiatry, Neurobiology, Pharmacology and Biotechnology, University of Pisa, Via Bonanno 6, Pisa 56126, Italy.
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Malatynska E, Pinhasov A, Creighton CJ, Crooke JJ, Reitz AB, Brenneman DE, Lubomirski MS. Assessing activity onset time and efficacy for clinically effective antidepressant and antimanic drugs in animal models based on dominant-submissive relationships. Neurosci Biobehav Rev 2007; 31:904-19. [PMID: 17597209 DOI: 10.1016/j.neubiorev.2007.05.004] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2007] [Revised: 05/14/2007] [Accepted: 05/16/2007] [Indexed: 11/16/2022]
Abstract
There is confusion in the literature on the measurement of the drug activity onset time (AOT) for both clinical and non-clinical studies of antidepressant and antimanic drugs. The questions asked are: How often and at which time points should drug effects be measured? At what level of a drug effect should AOT be determined? Is the placebo (control) effect important for consideration of drug AOT? This paper reviews approaches taken to answer these questions and to assess drug therapeutic AOT. The first part of the paper is devoted to a review of methods used in clinical trials with depression as an indication. The second part is focused on approaches taken in animal models of depression and how they could help in assessing drug AOT. Finally, a summary of pharmacological values on which the AOT depends is presented and a new statistical approach to data analysis method proposed. The allied experimental design for pre-clinical and clinical studies may help to characterize and differentiate AOT for available and new generation of antidepressants and antimanic drugs.
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Affiliation(s)
- Ewa Malatynska
- Drug Discovery, CNS Research Team, East Coast Research and Early Development, Johnson & Johnson Pharmaceutical Research & Development, P.O. Box 776, Welsh and McKean Rds., L.L.C., Spring House, PA 19477, USA.
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Paillet-Loilier M, Fabis F, Lepailleur A, Bureau R, Butt-Gueulle S, Dauphin F, Lesnard A, Delarue C, Vaudry H, Rault S. Novel aminoethylbiphenyls as 5-HT7 receptor ligands. Bioorg Med Chem Lett 2007; 17:3018-22. [PMID: 17419056 DOI: 10.1016/j.bmcl.2007.03.054] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2007] [Revised: 03/16/2007] [Accepted: 03/19/2007] [Indexed: 01/31/2023]
Abstract
The synthesis of a series of aminoethylbiphenyls as novel 5-HT(7) receptor ligands is described. The novel derivatives exhibit high affinity for the 5-HT(7) receptor with selectivity toward 5-HT(1A) receptor.
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Affiliation(s)
- Magalie Paillet-Loilier
- Centre d'Etudes et de Recherche sur le Médicament de Normandie EA3915, Université de Caen, UFR des Sciences Pharmaceutiques, 5, rue Vaubénard 14032 Caen Cedex, France
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Kumar JSD, Prabhakaran J, Majo VJ, Milak MS, Hsiung SC, Tamir H, Simpson NR, Van Heertum RL, Mann JJ, Parsey RV. Synthesis and in vivo evaluation of a novel 5-HT1A receptor agonist radioligand [O-methyl-11C]2-(4-(4-(2-methoxyphenyl)piperazin-1-yl)butyl)-4-methyl-1,2,4-triazine-3,5(2H,4H)dione in nonhuman primates. Eur J Nucl Med Mol Imaging 2007; 34:1050-60. [PMID: 17221184 DOI: 10.1007/s00259-006-0324-y] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2006] [Accepted: 11/05/2006] [Indexed: 12/25/2022]
Abstract
PURPOSE Serotonin1A (5-HT1A) receptors exist in high- and low-affinity states, and agonist ligands bind preferentially to the high-affinity state of the receptor and provide a measure of functional 5-HT1A receptors. Although the antagonist tracers are established PET ligands in clinical studies, a successful 5-HT1A receptor agonist radiotracer in living brain has not been reported. [11C]MPT, our first-generation agonist radiotracer, shows in vivo specificity in baboons; however, its utility is limited owing to slow washout and immeasurable plasma free fraction. Hence we performed structure-activity relationship studies of MPT to optimize a radiotracer that will permit valid quantification of 5-HT1A receptor binding. We now report the synthesis and evaluation of [11C]MMP as an agonist PET tracer for 5-HT1A receptors in baboons. METHODS In vitro binding assays were performed in bovine hippocampal membranes and membranes of CHO cells expressing 5-HT1A receptors. [11C] labeling of MMP was performed by reacting desmethyl-MMP with [11C]CH(3)OTf. In vivo studies were performed in baboons, and blocking studies were conducted by pretreatment with 5-HT1A receptor ligands WAY-100635 and (+/-)-8-OH-DPAT. RESULTS MMP is a selective 5-HT1A receptor agonist (Ki 0.15 nM). Radiosynthesis of [11C]MMP was achieved in 30 +/- 5% (n = 15) yield at EOS with a specific activity of 2,600 +/- 500 Ci/mmol (n = 12). PET studies in baboons demonstrated specific binding of [11C]MMP to 5-HT1A receptor-enriched brain regions, as confirmed by blockade with WAY-100635 and (+/-)-8-OH-DPAT. CONCLUSION We identified [11C]MMP as an optimal agonist PET tracer that shows quantifiable, specific binding in vivo to 5-HT1A receptors in baboons.
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Affiliation(s)
- J S Dileep Kumar
- Department of Psychiatry, Columbia University College of Physicians and Surgeons, New York, USA.
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Aznavour N, Zimmer L. [18F]MPPF as a tool for the in vivo imaging of 5-HT1A receptors in animal and human brain. Neuropharmacology 2006; 52:695-707. [PMID: 17101155 DOI: 10.1016/j.neuropharm.2006.09.023] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2006] [Revised: 09/21/2006] [Accepted: 09/29/2006] [Indexed: 11/18/2022]
Abstract
Serotonin (5-hydroxytryptamine, 5-HT) and its various receptors are involved in numerous CNS functions and psychiatric disorders. 5-HT(1A), the best-characterized subtype of currently known 5-HT receptors, is tightly implicated in the pathogenesis of depression, anxiety, epilepsy and eating disorders. It thus represents an important target for drug therapy. Specific radioligands and positron emission tomography (PET) allow for a quantitative imaging of brain 5-HT(1A) receptor distribution in living animals and humans. Recently, the selective 5-HT(1A) receptor antagonist, MPPF, has been successfully labeled with [(18)F]fluorine ([(18)F]MPPF), and an increasing number of academic and industry centres have used this radiotracer in preclinical and clinical studies. After a brief account of some of the structural, distributional and electrophysiological characteristics of brain 5-HT(1A) receptors, this review focuses on studies conducted with [(18)F]MPPF, with emphasis on preclinical results illustrating the actual and potential value of this PET radioligand for clinical research and drug development.
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Affiliation(s)
- Nicolas Aznavour
- Laboratoire de Neuropharmacologie, Université Lyon 1, Lyon, France
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Aznavour N, Rbah L, Riad M, Reilhac A, Costes N, Descarries L, Zimmer L. A PET imaging study of 5-HT1A receptors in cat brain after acute and chronic fluoxetine treatment. Neuroimage 2006; 33:834-42. [PMID: 16996750 DOI: 10.1016/j.neuroimage.2006.08.012] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2006] [Revised: 08/04/2006] [Accepted: 08/05/2006] [Indexed: 11/28/2022] Open
Abstract
Immuno-electron microscopic and beta-microprobe studies have demonstrated that the internalization of serotonin 5-HT(1A) autoreceptors, after acute treatment with the selective 5-HT(1A) receptor agonist 8-OH-DPAT or with the specific serotonin reuptake inhibitor (SSRI) fluoxetine, is associated with a marked decrease in the in vivo binding of [(18)F]MPPF in the nucleus raphe dorsalis (NRD) of rat. To determine whether this event might be amenable to brain imaging, the present [(18)F]MPPF positron emission tomographic (PET) study was carried out in anesthetized cats given or not a single dose (5 mg/kg, i.v.) or chronically treated with fluoxetine (5 mg/kg, s.c. for 21 days). Compared to control, [(18)F]MPPF binding potential was considerably (and visibly) decreased in the cat NRD after acute fluoxetine treatment, while it remained unchanged in other brain regions. Unexpectedly, after chronic fluoxetine treatment, [(18)F]MPPF binding potential was not affected in any brain region. In parallel immuno-electron microscopic experiments carried out in rat, the density of 5-HT(1A) autoreceptors on the plasma membrane of NRD dendrites was comparable to control after chronic fluoxetine treatment. If the decrease in [(18)F]MPPF binding at the onset of SSRI treatment was detectable by PET imaging, it could potentially serve as a biological index of efficacy.
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Affiliation(s)
- Nicolas Aznavour
- Laboratoire de Neuropharmacologie, Faculté de Pharmacie, Université Lyon 1, Lyon, France
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Tokugawa J, Ravasi L, Nakayama T, Lang L, Schmidt KC, Seidel J, Green MV, Sokoloff L, Eckelman WC. Distribution of the 5-HT(1A) receptor antagonist [ (18)F]FPWAY in blood and brain of the rat with and without isoflurane anesthesia. Eur J Nucl Med Mol Imaging 2006; 34:259-66. [PMID: 17021813 DOI: 10.1007/s00259-006-0228-x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2006] [Accepted: 07/03/2006] [Indexed: 11/26/2022]
Abstract
PURPOSE To determine whether brain and plasma equilibrium of a proposed PET tracer for 5-HT(1A), [(18)F]FPWAY, can be achieved in a sufficiently short time for practical use of the brain to plasma equilibrium distribution ratio (DR) to monitor receptor availability with and without isoflurane anesthesia. METHODS Awake (n=4) and isoflurane-anesthetized (n=4) rats were administered a continuous 60 min intravenous infusion of [(18)F]FPWAY with timed arterial blood sampling. Brains of the isoflurane-anesthetized rats were scanned with the ATLAS small animal PET scanner; awake rats were not. All rats were killed at 60 min and scanned postmortem for 15 min, followed by brain slicing for autoradiography. Several regions of interest (ROIs) were defined in the PET images as well as in the autoradiographic images. Regional DRs were calculated as total activity in the brain ROI divided by plasma [(18)F]FPWAY activity. RESULTS DRs in the anesthetized animals were constant between 30 and 60 min, indicating that near equilibrium between brain and plasma had been achieved by approximately 30 min. DRs determined from postmortem PET data were higher in the isoflurane-anesthetized rats by 24% (not significant) and 33% (p=0.065) in whole brain and hippocampus, respectively. DRs determined from autoradiographic data were greater in isoflurane-anesthetized rats in medial hippocampus, lateral hippocampus, and cerebellum by 33% (p=0.054), 63% (p<0.01), and 32% (p<0.05), respectively. CONCLUSION [(18)F]FPWAY could be an appropriate ligand for monitoring changes in receptor availability in the serotonergic system using a bolus/infusion paradigm. One possible explanation for higher DRs in anesthetized rats may be a reduction in endogenous 5-HT secretion under isoflurane anesthesia.
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Affiliation(s)
- Joji Tokugawa
- Positron Emission Tomography Department, Warren Grant Magnuson Clinical Center, National Institutes of Health, Bethesda, MD 20892, USA
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Parkel S, Rinken A. Characteristics of Binding of [3H]WAY100635 to Rat Hippocampal Membranes. Neurochem Res 2006; 31:1135-40. [PMID: 16937076 DOI: 10.1007/s11064-006-9135-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/02/2006] [Indexed: 10/24/2022]
Abstract
Kinetic analysis of binding of [(3)H][N-[2-[4-(2-[O-methyl-(3)H]methoxyphenyl)-1-piperazinyl]ethyl]-N-(2-pyridinyl)cyclohexane carboxamide ([(3)H]WAY100635) to 5-HT(1A) receptors in rat hippocampal membranes has revealed complex regulation mechanism for this radioligand. Saturation binding experiments revealed that [(3)H]WAY100635 binds to a single class of receptors with very high apparent affinity (K (D) = 87 +/- 4 pM, B (max) = 15.1 +/- 0.2 fmol/mg protein). The binding was almost irreversible, as the dissociation rate constant obtained k (off) = (7.8 +/- 1.1) x 10(-3) min(-1), means that equilibrium with this radioligand cannot be achieved before 7.5 h incubation at 25 degrees C. Systematic association kinetic studies of [(3)H]WAY100635 binding revealed sharp reaction acceleration at higher radioligand concentration, proposing mechanism of positive cooperativity. The affinities of antagonists determined from competition with [(3)H]WAY100635 did not coincide with their abilities to inhibit 5-HT-dependent activation of [(35)S]GTPgammaS binding probably due to the ligand's kinetic peculiarities. Thus, [(3)H]WAY100635 appears to be an excellent tool for determining receptor binding sites, but its applicability in equilibrium studies is strongly limited.
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Affiliation(s)
- Sven Parkel
- Institute of Organic and Bioorganic Chemistry, University of Tartu, Jakobi Str. 2, 51014, Tartu, Estonia.
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