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Alvarez-Herrera S, Rosel Vales M, Pérez-Sánchez G, Becerril-Villanueva E, Flores-Medina Y, Maldonado-García JL, Saracco-Alvarez R, Escamilla R, Pavón L. Risperidone Decreases Expression of Serotonin Receptor-2A (5-HT2A) and Serotonin Transporter (SERT) but Not Dopamine Receptors and Dopamine Transporter (DAT) in PBMCs from Patients with Schizophrenia. Pharmaceuticals (Basel) 2024; 17:167. [PMID: 38399382 PMCID: PMC10892557 DOI: 10.3390/ph17020167] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2023] [Revised: 12/20/2023] [Accepted: 12/22/2023] [Indexed: 02/25/2024] Open
Abstract
Dopamine and serotonin receptors and transporters play an essential role in the pathophysiology of schizophrenia; changes in their expression have been reported in neurons and leukocytes. Each antipsychotic induces a unique pattern in leukocyte function and phenotype. However, the use of polytherapy to treat schizophrenia makes it challenging to determine the specific effects of risperidone on peripheral blood mononuclear cells (PBMCs). The aim of this study was to evaluate the changes in the expression of D3, D5, DAT, 5-HT2A, and SERT in PBMCs from healthy volunteers (HV), drug-naive patients with schizophrenia (PWS), drug-free PWS, and PWS treated with risperidone for up to 40 weeks using quantitative PCR. Our study revealed elevated mRNA levels of D3, DAT, 5-HT2A, and SERT in unmedicated PWS. Treatment with risperidone led to a reduction only in the expression of 5-HT2A and SERT. Furthermore, we observed a moderate correlation between 5-HT2A expression and the positive and negative syndrome scale (PANSS), as well as SERT expression and PANSS scale. We also found a moderate correlation between 5-HT2A and SERT expression and the positive subscale. The duration of risperidone consumption had a significant negative correlation with the expression of 5-HT2A and SERT. Our study introduces the measurement of 5-HT2A and SERT expression in PBMCs as a useful parameter for assessing the response to risperidone in PWS.
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Affiliation(s)
- Samantha Alvarez-Herrera
- Laboratorio de Psicoinmunología, Dirección de Investigaciones en Neurociencias, Instituto Nacional de Psiquiatría Ramón de la Fuente Muñíz, Mexico City 14370, Mexico; (S.A.-H.); (G.P.-S.); (E.B.-V.)
| | - Mauricio Rosel Vales
- Clínica de Esquizofrenia, Dirección de Servicios Clínicos, Instituto Nacional de Psiquiatría Ramón de la Fuente Muñíz, Mexico City 14370, Mexico;
| | - Gilberto Pérez-Sánchez
- Laboratorio de Psicoinmunología, Dirección de Investigaciones en Neurociencias, Instituto Nacional de Psiquiatría Ramón de la Fuente Muñíz, Mexico City 14370, Mexico; (S.A.-H.); (G.P.-S.); (E.B.-V.)
| | - Enrique Becerril-Villanueva
- Laboratorio de Psicoinmunología, Dirección de Investigaciones en Neurociencias, Instituto Nacional de Psiquiatría Ramón de la Fuente Muñíz, Mexico City 14370, Mexico; (S.A.-H.); (G.P.-S.); (E.B.-V.)
| | - Yvonne Flores-Medina
- Subdirección de Investigaciones Clínicas, Instituto Nacional de Psiquiatría Ramón de la Fuente Muñíz, Mexico City 14370, Mexico; (Y.F.-M.); (R.S.-A.)
| | - José Luis Maldonado-García
- Departamemto de Inmunología, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, Mexico City 11340, Mexico;
- Departamemto de Bioquímica, Facultad de Medicina, Universidad Nacional Autónoma de México, Mexico City 04510, Mexico
| | - Ricardo Saracco-Alvarez
- Subdirección de Investigaciones Clínicas, Instituto Nacional de Psiquiatría Ramón de la Fuente Muñíz, Mexico City 14370, Mexico; (Y.F.-M.); (R.S.-A.)
| | - Raúl Escamilla
- Subdirección de Consulta Externa, Instituto Nacional de Psiquiatría Ramón de la Fuente Muñíz, Mexico City 14370, Mexico;
| | - Lenin Pavón
- Laboratorio de Psicoinmunología, Dirección de Investigaciones en Neurociencias, Instituto Nacional de Psiquiatría Ramón de la Fuente Muñíz, Mexico City 14370, Mexico; (S.A.-H.); (G.P.-S.); (E.B.-V.)
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2
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Singh P, Singh D, Srivastava P, Mishra G, Tiwari AK. Evaluation of advanced, pathophysiologic new targets for imaging of CNS. Drug Dev Res 2023; 84:484-513. [PMID: 36779375 DOI: 10.1002/ddr.22040] [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: 10/23/2022] [Revised: 12/12/2022] [Accepted: 12/31/2022] [Indexed: 02/14/2023]
Abstract
The inadequate information about the in vivo pathological, physiological, and neurological impairments, as well as the absence of in vivo tools for assessing brain penetrance and the efficiency of newly designed drugs, has hampered the development of new techniques for the treatment for variety of new central nervous system (CNS) diseases. The searching sites such as Science Direct and PubMed were used to find out the numerous distinct tracers across 16 CNS targets including tau, synaptic vesicle glycoprotein, the adenosine 2A receptor, the phosphodiesterase enzyme PDE10A, and the purinoceptor, among others. Among the most encouraging are [18 F]FIMX for mGluR imaging, [11 C]Martinostat for Histone deacetylase, [18 F]MNI-444 for adenosine 2A imaging, [11 C]ER176 for translocator protein, and [18 F]MK-6240 for tau imaging. We also reviewed the findings for each tracer's features and potential for application in CNS pathophysiology and therapeutic evaluation investigations, including target specificity, binding efficacy, and pharmacokinetic factors. This review aims to present a current evaluation of modern positron emission tomography tracers for CNS targets, with a focus on recent advances for targets that have newly emerged for imaging in humans.
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Affiliation(s)
- Priya Singh
- Department of Chemistry, Babasaheb Bhimrao Ambedkar University, Lucknow, Uttar Pradesh, India
| | - Deepika Singh
- Department of Chemistry, Babasaheb Bhimrao Ambedkar University, Lucknow, Uttar Pradesh, India
| | - Pooja Srivastava
- Division of Cyclotron and Radiopharmaceuticals Sciences, Institute of Nuclear Medicine and Allied Sciences, Delhi, India
| | - Gauri Mishra
- Department of Zoology, Swami Shraddhananad College, University of Delhi, Alipur, Delhi, India
| | - Anjani K Tiwari
- Department of Chemistry, Babasaheb Bhimrao Ambedkar University, Lucknow, Uttar Pradesh, India
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3
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Fu H, Rong J, Chen Z, Zhou J, Collier T, Liang SH. Positron Emission Tomography (PET) Imaging Tracers for Serotonin Receptors. J Med Chem 2022; 65:10755-10808. [PMID: 35939391 DOI: 10.1021/acs.jmedchem.2c00633] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Serotonin (5-hydroxytryptamine, 5-HT) and 5-HT receptors (5-HTRs) have crucial roles in various neuropsychiatric disorders and neurodegenerative diseases, making them attractive diagnostic and therapeutic targets. Positron emission tomography (PET) is a noninvasive nuclear molecular imaging technique and is an essential tool in clinical diagnosis and drug discovery. In this context, numerous PET ligands have been developed for "visualizing" 5-HTRs in the brain and translated into human use to study disease mechanisms and/or support drug development. Herein, we present a comprehensive repertoire of 5-HTR PET ligands by focusing on their chemotypes and performance in PET imaging studies. Furthermore, this Perspective summarizes recent 5-HTR-focused drug discovery, including biased agonists and allosteric modulators, which would stimulate the development of more potent and subtype-selective 5-HTR PET ligands and thus further our understanding of 5-HTR biology.
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Affiliation(s)
- Hualong Fu
- Key Laboratory of Radiopharmaceuticals, Ministry of Education, College of Chemistry, Beijing Normal University, Beijing 100875, China
| | - Jian Rong
- Division of Nuclear Medicine and Molecular Imaging, Massachusetts General Hospital, Boston, Massachusetts 02114, United States.,Department of Radiology, Harvard Medical School, Boston, Massachusetts 02115, United States
| | - Zhen Chen
- Jiangsu Co-Innovation Center of Efficient Processing and Utilization of Forest Resources, International Innovation Center for Forest Chemicals and Materials, College of Chemical Engineering, Nanjing Forestry University, Nanjing, Jiangsu 210037, China
| | - Jingyin Zhou
- Key Laboratory of Radiopharmaceuticals, Ministry of Education, College of Chemistry, Beijing Normal University, Beijing 100875, China
| | - Thomas Collier
- Division of Nuclear Medicine and Molecular Imaging, Massachusetts General Hospital, Boston, Massachusetts 02114, United States.,Department of Radiology, Harvard Medical School, Boston, Massachusetts 02115, United States
| | - Steven H Liang
- Division of Nuclear Medicine and Molecular Imaging, Massachusetts General Hospital, Boston, Massachusetts 02114, United States.,Department of Radiology, Harvard Medical School, Boston, Massachusetts 02115, United States
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4
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Ikoma Y, Takuwa H, Nishino A, Maeda J, Kawamura K, Obata T, Zhang MR, Higuchi M, Suhara T. Measurement of changes in endogenous serotonin level by positron emission tomography with [ 18F]altanserin. Ann Nucl Med 2021; 35:955-965. [PMID: 34101154 DOI: 10.1007/s12149-021-01633-4] [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: 12/08/2020] [Accepted: 05/18/2021] [Indexed: 11/29/2022]
Abstract
OBJECTIVE Positron emission tomography (PET) has been used to investigate changes in the concentration of endogenous neurotransmitters. Recently, this technique has been applied to the imaging of serotonin2A receptors using [18F]altanserin. In these measurements, a reduction in binding potential (BP) suggests an increase in endogenous serotonin levels caused by pharmacological or cognitive stimulations, and the sensitivity of BP reduction depends on the characteristics of [18F]altanserin. In this study, we evaluated an analytical method for estimating the changes in endogenous serotonin levels based on PET scans with [18F]altanserin at baseline and stimulated states and validated it using simulations and small animal PET studies. METHODS First, in the simulations, the time-activity curves at baseline and the stimulated states were generated using an extended compartment model including the competition for the receptors between the administered [18F]altanserin and endogenous serotonin. In the stimulated state, the magnitude and onset of the endogenous serotonin elevation were altered to varying degrees. In these time-activity curves, BP was estimated using the simplified reference tissue model (SRTM), and the reduction in BP was evaluated by comparison with that of the baseline state. Next, the proposed method was applied to mouse PET studies. Endogenous serotonin levels were elevated by treatment with selective serotonin reuptake inhibitors (SSRIs), and PET studies were performed twice, once with and once without treatment. In both scans, BP was estimated using the SRTM with the cerebellum as a reference region, and the reduction in BP after SSRI treatment was evaluated. RESULTS In the simulations, the BP estimate of the stimulated state was smaller than that of the baseline state, and their reduction was related to the amount of change in the serotonin concentration. BP reduction was also affected by the onset of serotonin elevation. In the mouse studies, the BP of the cerebral cortex decreased in the scans with SSRI treatment. CONCLUSIONS The reduction in BP estimated using the SRTM from [18F]altanserin-PET studies at baseline and in stimulated states can detect changes in the binding conditions of serotonin2A receptors. This may be useful for investigating the elevation of endogenous serotonin levels caused by stimulations.
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Affiliation(s)
- Yoko Ikoma
- Department of Molecular Imaging and Theranostics, Institute for Quantum Medical Science, National Institute for Quantum and Radiological Science and Technology, 4-9-1 Anagawa, Inage-ku, Chiba, 263-8555, Japan.
| | - Hiroyuki Takuwa
- Department of Functional Brain Imaging, Institute for Quantum Medical Science, National Institute for Quantum and Radiological Science and Technology, 4-9-1 Anagawa, Inage-ku, Chiba, 263-8555, Japan
| | - Asuka Nishino
- Department of Functional Brain Imaging, Institute for Quantum Medical Science, National Institute for Quantum and Radiological Science and Technology, 4-9-1 Anagawa, Inage-ku, Chiba, 263-8555, Japan.,Department of Biological Sciences, Faculty of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan
| | - Jun Maeda
- Department of Functional Brain Imaging, Institute for Quantum Medical Science, National Institute for Quantum and Radiological Science and Technology, 4-9-1 Anagawa, Inage-ku, Chiba, 263-8555, Japan
| | - Kazunori Kawamura
- Department of Advanced Nuclear Medicine Sciences, Institute for Quantum Medical Science, National Institute for Quantum and Radiological Science and Technology, 4-9-1 Anagawa, Inage-ku, Chiba, 263-8555, Japan
| | - Takayuki Obata
- Department of Molecular Imaging and Theranostics, Institute for Quantum Medical Science, National Institute for Quantum and Radiological Science and Technology, 4-9-1 Anagawa, Inage-ku, Chiba, 263-8555, Japan
| | - Ming-Rong Zhang
- Department of Advanced Nuclear Medicine Sciences, Institute for Quantum Medical Science, National Institute for Quantum and Radiological Science and Technology, 4-9-1 Anagawa, Inage-ku, Chiba, 263-8555, Japan
| | - Makoto Higuchi
- Department of Functional Brain Imaging, Institute for Quantum Medical Science, National Institute for Quantum and Radiological Science and Technology, 4-9-1 Anagawa, Inage-ku, Chiba, 263-8555, Japan
| | - Tetsuya Suhara
- Department of Functional Brain Imaging, Institute for Quantum Medical Science, National Institute for Quantum and Radiological Science and Technology, 4-9-1 Anagawa, Inage-ku, Chiba, 263-8555, Japan
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5
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Opposite alterations of 5-HT 2A receptor brain density in subjects with schizophrenia: relevance of radiotracers pharmacological profile. Transl Psychiatry 2021; 11:302. [PMID: 34016955 PMCID: PMC8137947 DOI: 10.1038/s41398-021-01430-7] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/01/2020] [Revised: 04/26/2021] [Accepted: 05/05/2021] [Indexed: 02/04/2023] Open
Abstract
The status of serotonin 5-HT2A receptors (5-HT2ARs) in schizophrenia has been controversial. In vivo positron emission tomography neuroimaging and in vitro post-mortem binding studies have reported conflicting results about 5-HT2AR density. Radiotracers bind different receptor conformations depending on their agonist, antagonist or inverse agonist properties. This study investigates 5-HT2AR density in the post-mortem prefrontal cortex from subjects with schizophrenia and controls using three radiotracers with a different pharmacological profile. The specific binding parameters of the inverse agonist [18F]altanserin, the agonist [3H]lysergic acid diethylamide (LSD) and the antagonist [3H]MDL100907 to brain cortex membranes from 20 subjects with schizophrenia and 20 individually matched controls were evaluated under similar methodological conditions. Ten schizophrenia subjects were antipsychotic-free at death. Saturation curve analyses were performed by non-linear regression to obtain a maximal density of binding sites (Bmax) and the affinity of the respective radiotracers (Kd). In schizophrenia subjects, 5-HT2AR density was decreased when quantified by [18F]altanserin binding, whereas increased when evaluated by [3H]LSD binding. However, [3H]MDL100907 binding was unaltered. A slight loss of affinity (higher Kd) was observed exclusively in [3H]LSD binding. The findings were more evident in antipsychotic-free subjects than in antipsychotic-treated subjects. In conclusion, a higher proportion of the 5-HT2AR-active functional conformation, which is rather identified by agonist radiotracers, was observed in schizophrenia patients. A consequent reduction of the inactive 5-HT2AR conformation, which is preferentially identified by inverse agonist radiotracers, was also obtained. Antagonist radiotracers do not distinguish between molecular conformations of the receptor, and accordingly, the absence of changes was shown. These results are compatible with the proposed increased functional activity of brain cortical 5-HT2ARs in schizophrenia.
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Abstract
This paper introduces a new construct, the 'pivotal mental state', which is defined as a hyper-plastic state aiding rapid and deep learning that can mediate psychological transformation. We believe this new construct bears relevance to a broad range of psychological and psychiatric phenomena. We argue that pivotal mental states serve an important evolutionary function, that is, to aid psychological transformation when actual or perceived environmental pressures demand this. We cite evidence that chronic stress and neurotic traits are primers for a pivotal mental state, whereas acute stress can be a trigger. Inspired by research with serotonin 2A receptor agonist psychedelics, we highlight how activity at this particular receptor can robustly and reliably induce pivotal mental states, but we argue that the capacity for pivotal mental states is an inherent property of the human brain itself. Moreover, we hypothesize that serotonergic psychedelics hijack a system that has evolved to mediate rapid and deep learning when its need is sensed. We cite a breadth of evidences linking stress via a variety of inducers, with an upregulated serotonin 2A receptor system (e.g. upregulated availability of and/or binding to the receptor) and acute stress with 5-HT release, which we argue can activate this primed system to induce a pivotal mental state. The pivotal mental state model is multi-level, linking a specific molecular gateway (increased serotonin 2A receptor signaling) with the inception of a hyper-plastic brain and mind state, enhanced rate of associative learning and the potential mediation of a psychological transformation.
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Affiliation(s)
- Ari Brouwer
- Centre for Psychedelic Research, Imperial College London, London, United Kingdom
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7
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Cumming P, Abi-Dargham A, Gründer G. Molecular imaging of schizophrenia: Neurochemical findings in a heterogeneous and evolving disorder. Behav Brain Res 2020; 398:113004. [PMID: 33197459 DOI: 10.1016/j.bbr.2020.113004] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2020] [Revised: 10/22/2020] [Accepted: 10/31/2020] [Indexed: 02/07/2023]
Abstract
The past four decades have seen enormous efforts placed on a search for molecular markers of schizophrenia using positron emission tomography (PET) and single photon emission computed tomography (SPECT). In this narrative review, we cast a broad net to define and summarize what researchers have learned about schizophrenia from molecular imaging studies. Some PET studies of brain energy metabolism with the glucose analogue FDGhave have shown a hypofrontality defect in patients with schizophrenia, but more generally indicate a loss of metabolic coherence between different brain regions. An early finding of significantly increased striatal trapping of the dopamine synthesis tracer FDOPA has survived a meta-analysis of many replications, but the increase is not pathognomonic of the disorder, since one half of patients have entirely normal dopamine synthesis capacity. Similarly, competition SPECT studies show greater basal and amphetamine-evoked dopamine occupancy at post-synaptic dopamine D2/3 receptors in patients with schizophrenia, but the difference is likewise not pathognomonic. We thus propose that molecular imaging studies of brain dopamine indicate neurochemical heterogeneity within the diagnostic entity of schizophrenia. Occupancy studies have established the relevant target engagement by antipsychotic medications at dopamine D2/3 receptors in living brain. There is evidence for elevated frontal cortical dopamine D1 receptors, especially in relation to cognitive deficits in schizophrenia. There is a general lack of consistent findings of abnormalities in serotonin markers, but some evidence for decreased levels of nicotinic receptors in patients. There are sparse and somewhat inconsistent findings of reduced binding of muscarinic, glutamate, and opioid receptors ligands, inconsistent findings of microglial activation, and very recently, evidence of globally reduced levels of synaptic proteins in brain of patients. One study reports a decline in histone acetylase binding that is confined to the dorsolateral prefrontal cortex. In most contexts, the phase of the disease and effects of past or present medication can obscure or confound PET and SPECT findings in schizophrenia.
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Affiliation(s)
- Paul Cumming
- Department of Nuclear Medicine, Inselspital, Bern University, Bern, Switzerland; School of Psychology and Counselling, Queensland University of Technology, Brisbane, Australia.
| | - Anissa Abi-Dargham
- Stony Brook University, Renaissance School of Medicine, Stony Brook, New York, USA
| | - Gerhard Gründer
- Central Institute of Mental Health, Department of Molecular Neuroimaging, Medical Faculty Mannheim, University of Heidelberg, Mannheim, Germany
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8
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Spies M, Nasser A, Ozenne B, Jensen PS, Knudsen GM, Fisher PM. Common HTR2A variants and 5-HTTLPR are not associated with human in vivo serotonin 2A receptor levels. Hum Brain Mapp 2020; 41:4518-4528. [PMID: 32697408 PMCID: PMC7555071 DOI: 10.1002/hbm.25138] [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: 01/30/2020] [Revised: 05/08/2020] [Accepted: 06/16/2020] [Indexed: 12/22/2022] Open
Abstract
The serotonin 2A receptor (5‐HT2AR) is implicated in the pathophysiology and treatment of various psychiatric disorders. [18F]altanserin and [11C]Cimbi‐36 positron emission tomography (PET) allow for high‐resolution imaging of 5‐HT2AR in the living human brain. Cerebral 5‐HT2AR binding is strongly genetically determined, though the impact of specific variants is poorly understood. Candidate gene studies suggest that HTR2A single nucleotide polymorphisms including rs6311/rs6313, rs6314, and rs7997012 may influence risk for psychiatric disorders and mediate treatment response. Although known to impact in vitro expression of 5‐HT2AR or other serotonin (5‐HT) proteins, their effect on human in vivo brain 5‐HT2AR binding has as of yet been insufficiently studied. We thus assessed the extent to which these variants and the commonly studied 5‐HTTLPR predict neocortex in vivo 5‐HT2AR binding in healthy adult humans. We used linear regression analyses and likelihood ratio tests in 197 subjects scanned with [18F]altanserin or [11C]Cimbi‐36 PET. Although we observed genotype group differences in 5‐HT2AR binding of up to ~10%, no genetic variants were statistically significantly predictive of 5‐HT2AR binding in what is the largest human in vivo 5‐HT2AR imaging genetics study to date. Thus, in vitro and post mortem results suggesting effects on 5‐HT2AR expression did not carry over to the in vivo setting. To any extent these variants might affect clinical risk, our findings do not support that 5‐HT2AR binding mediates such effects. Our observations indicate that these individual variants do not significantly contribute to genetic load on human in vivo 5‐HT2AR binding.
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Affiliation(s)
- Marie Spies
- Neurobiology Research Unit, Rigshospitalet, Copenhagen, Denmark.,Department of Psychiatry and Psychotherapy, Medical University of Vienna, Vienna, Austria
| | - Arafat Nasser
- Neurobiology Research Unit, Rigshospitalet, Copenhagen, Denmark
| | - Brice Ozenne
- Neurobiology Research Unit, Rigshospitalet, Copenhagen, Denmark.,Department of Public Health, Section of Biostatistics, University of Copenhagen, Copenhagen, Denmark
| | - Peter S Jensen
- Neurobiology Research Unit, Rigshospitalet, Copenhagen, Denmark
| | - Gitte M Knudsen
- Neurobiology Research Unit, Rigshospitalet, Copenhagen, Denmark
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McCluskey SP, Plisson C, Rabiner EA, Howes O. Advances in CNS PET: the state-of-the-art for new imaging targets for pathophysiology and drug development. Eur J Nucl Med Mol Imaging 2020; 47:451-489. [PMID: 31541283 PMCID: PMC6974496 DOI: 10.1007/s00259-019-04488-0] [Citation(s) in RCA: 73] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2019] [Accepted: 08/15/2019] [Indexed: 02/07/2023]
Abstract
PURPOSE A limit on developing new treatments for a number of central nervous system (CNS) disorders has been the inadequate understanding of the in vivo pathophysiology underlying neurological and psychiatric disorders and the lack of in vivo tools to determine brain penetrance, target engagement, and relevant molecular activity of novel drugs. Molecular neuroimaging provides the tools to address this. This article aims to provide a state-of-the-art review of new PET tracers for CNS targets, focusing on developments in the last 5 years for targets recently available for in-human imaging. METHODS We provide an overview of the criteria used to evaluate PET tracers. We then used the National Institute of Mental Health Research Priorities list to identify the key CNS targets. We conducted a PubMed search (search period 1st of January 2013 to 31st of December 2018), which yielded 40 new PET tracers across 16 CNS targets which met our selectivity criteria. For each tracer, we summarised the evidence of its properties and potential for use in studies of CNS pathophysiology and drug evaluation, including its target selectivity and affinity, inter and intra-subject variability, and pharmacokinetic parameters. We also consider its potential limitations and missing characterisation data, but not specific applications in drug development. Where multiple tracers were present for a target, we provide a comparison of their properties. RESULTS AND CONCLUSIONS Our review shows that multiple new tracers have been developed for proteinopathy targets, particularly tau, as well as the purinoceptor P2X7, phosphodiesterase enzyme PDE10A, and synaptic vesicle glycoprotein 2A (SV2A), amongst others. Some of the most promising of these include 18F-MK-6240 for tau imaging, 11C-UCB-J for imaging SV2A, 11C-CURB and 11C-MK-3168 for characterisation of fatty acid amide hydrolase, 18F-FIMX for metabotropic glutamate receptor 1, and 18F-MNI-444 for imaging adenosine 2A. Our review also identifies recurrent issues within the field. Many of the tracers discussed lack in vivo blocking data, reducing confidence in selectivity. Additionally, late-stage identification of substantial off-target sites for multiple tracers highlights incomplete pre-clinical characterisation prior to translation, as well as human disease state studies carried out without confirmation of test-retest reproducibility.
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Affiliation(s)
- Stuart P McCluskey
- Invicro LLC, A Konica Minolta Company, Burlington Danes Building, Imperial College London, Hammersmith Hospital, Du Cane Road, London, W12 0NN, UK.
- Psychiatric Imaging Group, MRC London Institute of Medical Sciences, Imperial College London, Hammersmith Hospital, London, UK.
| | - Christophe Plisson
- Invicro LLC, A Konica Minolta Company, Burlington Danes Building, Imperial College London, Hammersmith Hospital, Du Cane Road, London, W12 0NN, UK
| | - Eugenii A Rabiner
- Invicro LLC, A Konica Minolta Company, Burlington Danes Building, Imperial College London, Hammersmith Hospital, Du Cane Road, London, W12 0NN, UK
| | - Oliver Howes
- Psychiatric Imaging Group, MRC London Institute of Medical Sciences, Imperial College London, Hammersmith Hospital, London, UK
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10
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García-Bea A, Miranda-Azpiazu P, Muguruza C, Marmolejo-Martinez-Artesero S, Diez-Alarcia R, Gabilondo AM, Callado LF, Morentin B, González-Maeso J, Meana JJ. Serotonin 5-HT 2A receptor expression and functionality in postmortem frontal cortex of subjects with schizophrenia: Selective biased agonism via G αi1-proteins. Eur Neuropsychopharmacol 2019; 29:1453-1463. [PMID: 31734018 DOI: 10.1016/j.euroneuro.2019.10.013] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/08/2019] [Revised: 10/17/2019] [Accepted: 10/29/2019] [Indexed: 12/20/2022]
Abstract
Serotonin 5-HT2A receptors (5-HT2ARs) have been implicated in schizophrenia. However, postmortem studies on 5-HT2ARs expression and functionality in schizophrenia are scarce. The 5-HT2AR mRNA and immunoreactive protein expression were evaluated in postmortem tissue from dorsolateral prefrontal cortex (DLPFC) of antipsychotic-free (n = 18) and antipsychotic-treated (n = 9) subjects with schizophrenia, and matched controls (n = 27). Functional coupling of 5-HT2AR to G-proteins was tested by measuring the activation induced by the agonist (±)-2,5-dimethoxy-4-iodoamphetamine hydrochloride ((±)DOI) in antibody-capture [35S]GTPγS scintillation proximity assays (SPA). In antipsychotic-free schizophrenia subjects, 5-HT2AR mRNA expression and protein immunoreactivity in total homogenates was similar to controls. In contrast, in antipsychotic-treated schizophrenia subjects, lower mRNA expression (60±9% vs controls) and a trend to reduced protein immunoreactivity (86±5% vs antipsychotic-free subjects) just in membrane-enriched fractions was observed. [35S]GTPγS SPA revealed a significant ~6% higher stimulation of Gαi1-protein by (±)DOI in schizophrenia, whereas activation of the canonical Gαq/11-protein pathway by (±)DOI remained unchanged. Expression of Gαi1- and Gαq/11-proteins did not differ between groups. Accordingly, in rats chronically treated with clozapine, but not with haloperidol, a 30-40% reduction was observed in 5-HT2AR mRNA expression, 5-HT2AR protein immunoreactivity and [3H]ketanserin binding in brain cortical membranes. Overall, the data suggest a supersensitive 5-HT2AR signaling through inhibitory Gαi1-proteins in schizophrenia. Together with previous results, a dysfunctional pro-hallucinogenic agonist-sensitive 5-HT2AR conformation in postmortem DLPFC of subjects with schizophrenia is proposed. Atypical antipsychotic treatment would contribute to counterbalance this 5-HT2AR supersensitivity by reducing receptor expression.
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Affiliation(s)
- Aintzane García-Bea
- Department of Pharmacology, University of the Basque Country UPV/EHU, 48940 Leioa, Bizkaia, Spain; Centro de Investigación Biomédica en Red de Salud Mental, CIBERSAM, Spain
| | - Patricia Miranda-Azpiazu
- Department of Pharmacology, University of the Basque Country UPV/EHU, 48940 Leioa, Bizkaia, Spain; Centro de Investigación Biomédica en Red de Salud Mental, CIBERSAM, Spain
| | - Carolina Muguruza
- Department of Pharmacology, University of the Basque Country UPV/EHU, 48940 Leioa, Bizkaia, Spain; Centro de Investigación Biomédica en Red de Salud Mental, CIBERSAM, Spain
| | | | - Rebeca Diez-Alarcia
- Department of Pharmacology, University of the Basque Country UPV/EHU, 48940 Leioa, Bizkaia, Spain; Centro de Investigación Biomédica en Red de Salud Mental, CIBERSAM, Spain; Biocruces Bizkaia Health Research Institute, Spain
| | - Ane M Gabilondo
- Department of Pharmacology, University of the Basque Country UPV/EHU, 48940 Leioa, Bizkaia, Spain; Centro de Investigación Biomédica en Red de Salud Mental, CIBERSAM, Spain; Biocruces Bizkaia Health Research Institute, Spain
| | - Luis F Callado
- Department of Pharmacology, University of the Basque Country UPV/EHU, 48940 Leioa, Bizkaia, Spain; Centro de Investigación Biomédica en Red de Salud Mental, CIBERSAM, Spain; Biocruces Bizkaia Health Research Institute, Spain
| | - Benito Morentin
- Biocruces Bizkaia Health Research Institute, Spain; Basque Institute of Legal Medicine, Spain
| | - Javier González-Maeso
- Department of Physiology and Biophysics, Virginia Commonwealth University School of Medicine, VA, USA
| | - J Javier Meana
- Department of Pharmacology, University of the Basque Country UPV/EHU, 48940 Leioa, Bizkaia, Spain; Centro de Investigación Biomédica en Red de Salud Mental, CIBERSAM, Spain; Biocruces Bizkaia Health Research Institute, Spain.
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11
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Beaurain M, Salabert AS, Ribeiro MJ, Arlicot N, Damier P, Le Jeune F, Demonet JF, Payoux P. Innovative Molecular Imaging for Clinical Research, Therapeutic Stratification, and Nosography in Neuroscience. Front Med (Lausanne) 2019; 6:268. [PMID: 31828073 PMCID: PMC6890558 DOI: 10.3389/fmed.2019.00268] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2019] [Accepted: 11/01/2019] [Indexed: 01/06/2023] Open
Abstract
Over the past few decades, several radiotracers have been developed for neuroimaging applications, especially in PET. Because of their low steric hindrance, PET radionuclides can be used to label molecules that are small enough to cross the blood brain barrier, without modifying their biological properties. As the use of 11C is limited by its short physical half-life (20 min), there has been an increasing focus on developing tracers labeled with 18F for clinical use. The first such tracers allowed cerebral blood flow and glucose metabolism to be measured, and the development of molecular imaging has since enabled to focus more closely on specific targets such as receptors, neurotransmitter transporters, and other proteins. Hence, PET and SPECT biomarkers have become indispensable for innovative clinical research. Currently, the treatment options for a number of pathologies, notably neurodegenerative diseases, remain only supportive and symptomatic. Treatments that slow down or reverse disease progression are therefore the subject of numerous studies, in which molecular imaging is proving to be a powerful tool. PET and SPECT biomarkers already make it possible to diagnose several neurological diseases in vivo and at preclinical stages, yielding topographic, and quantitative data about the target. As a result, they can be used for assessing patients' eligibility for new treatments, or for treatment follow-up. The aim of the present review was to map major innovative radiotracers used in neuroscience, and explain their contribution to clinical research. We categorized them according to their target: dopaminergic, cholinergic or serotoninergic systems, β-amyloid plaques, tau protein, neuroinflammation, glutamate or GABA receptors, or α-synuclein. Most neurological disorders, and indeed mental disorders, involve the dysfunction of one or more of these targets. Combinations of molecular imaging biomarkers can afford us a better understanding of the mechanisms underlying disease development over time, and contribute to early detection/screening, diagnosis, therapy delivery/monitoring, and treatment follow-up in both research and clinical settings.
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Affiliation(s)
- Marie Beaurain
- CHU de Toulouse, Toulouse, France.,ToNIC, Toulouse NeuroImaging Center, Inserm U1214, Toulouse, France
| | - Anne-Sophie Salabert
- CHU de Toulouse, Toulouse, France.,ToNIC, Toulouse NeuroImaging Center, Inserm U1214, Toulouse, France
| | - Maria Joao Ribeiro
- UMR 1253, iBrain, Université de Tours, Inserm, Tours, France.,Inserm CIC 1415, University Hospital, Tours, France.,CHRU Tours, Tours, France
| | - Nicolas Arlicot
- UMR 1253, iBrain, Université de Tours, Inserm, Tours, France.,Inserm CIC 1415, University Hospital, Tours, France.,CHRU Tours, Tours, France
| | - Philippe Damier
- Inserm U913, Neurology Department, University Hospital, Nantes, France
| | | | - Jean-François Demonet
- Leenards Memory Centre, Department of Clinical Neuroscience, Centre Hospitalier Universitaire Vaudois, Lausanne, Switzerland
| | - Pierre Payoux
- CHU de Toulouse, Toulouse, France.,ToNIC, Toulouse NeuroImaging Center, Inserm U1214, Toulouse, France
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12
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Stenkrona P, Matheson GJ, Halldin C, Cervenka S, Farde L. D1-Dopamine Receptor Availability in First-Episode Neuroleptic Naive Psychosis Patients. Int J Neuropsychopharmacol 2019; 22:415-425. [PMID: 30958880 PMCID: PMC6600463 DOI: 10.1093/ijnp/pyz017] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/10/2019] [Revised: 03/12/2019] [Accepted: 04/05/2019] [Indexed: 01/02/2023] Open
Abstract
BACKGROUND Positron emission tomography studies examining differences in D1-dopamine receptor binding between control subjects and patients with schizophrenia have been inconsistent, reporting higher, lower, and no difference in the frontal cortex. Exposure to antipsychotic medication has been suggested to be a likely source of this heterogeneity, and thus there is a need for studies of patients at early stages of the disorder who have not been exposed to such drugs. METHODS Here, we compared 17 healthy control subjects and 18 first-episode neuroleptic naive patients with schizophrenia or schizophreniform psychosis using positron emission tomography and the D1-dopamine receptor radioligand [11C]SCH23390. RESULTS We observed a statistically significant difference in the dorsolateral prefrontal cortex. Contrary to our expectations, patients had less D1-dopamine receptor availability with a moderate effect size. In a Bayesian analysis, we show that the data are over 50 times more likely to have occurred under the decrease as opposed to the increase hypothesis. This effect was not global, as our analysis showed that the null hypothesis was preferred over either hypothesis in the striatum. CONCLUSIONS This investigation represents the largest single sample of neuroleptic-naive patients examined for D1-dopamine receptor availability using PET and suggests a reduction of prefrontal D1-dopamine receptor density in the pathophysiology of schizophrenia. However, further work will be required to reach a consensus.
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Affiliation(s)
- Per Stenkrona
- Department of Clinical Neuroscience, Centre for Psychiatry Research, Karolinska Institutet and Stockholm County Council, Stockholm, Sweden,Correspondence: Per Stenkrona, MD, Karolinska Institutet, Department of Clinical Neuroscience Karolinska University Hospital, R5:02 SE-171 76 Stockholm, Sweden ()
| | - Granville J Matheson
- Department of Clinical Neuroscience, Centre for Psychiatry Research, Karolinska Institutet and Stockholm County Council, Stockholm, Sweden
| | - Christer Halldin
- Department of Clinical Neuroscience, Centre for Psychiatry Research, Karolinska Institutet and Stockholm County Council, Stockholm, Sweden
| | - Simon Cervenka
- Department of Clinical Neuroscience, Centre for Psychiatry Research, Karolinska Institutet and Stockholm County Council, Stockholm, Sweden
| | - Lars Farde
- Department of Clinical Neuroscience, Centre for Psychiatry Research, Karolinska Institutet and Stockholm County Council, Stockholm, Sweden,PET Science Centre, Precision Medicine, R&D Oncology, AstraZeneca, Karolinska Institutet, Sweden
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13
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Dean B, Copolov D, Scarr E. Understanding the pathophysiology of schizophrenia: Contributions from the Melbourne Psychiatric Brain Bank. Schizophr Res 2016; 177:108-114. [PMID: 27184458 DOI: 10.1016/j.schres.2016.04.037] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/02/2016] [Revised: 04/20/2016] [Accepted: 04/23/2016] [Indexed: 11/24/2022]
Abstract
The Melbourne Psychiatric Brain Bank came into existence 25years ago. This review focusses on lines of research that have used tissue from the Brain Bank over periods of time. Hence there is a discussion on the significance of changes in levels of serotonin 2A receptors in the cortex of patients with schizophrenia and the relevance of such changes with regards to the pathophysiology of the disorder. The extensive contribution made by studies using tissue from the Melbourne Psychiatric Brain Bank to understanding the role of muscarinic receptors in the pathophysiology and treatment of schizophrenia is summarised. Finally, findings using brain bank tissue and "omics" technologies are reviewed. In each case, findings using tissue from the Melbourne Psychiatric Brain Bank is placed in context with research carried out on human postmortem CNS in schizophrenia and with findings in other lines of research that can help explain the causes or consequences of changes in CNS molecular cytoarchitecture. This timely review of data from the Melbourne Psychiatric Brain Bank reinforces the challenges faced in trying to increase our understanding of the molecular pathophysiology of schizophrenia. Continuing to increase our understanding of the disorder is important as a precursor to identifying new drug targets that can be exploited to improve the treatment of a disorder where treatment resistance remains a significant problem (Millan et al., 2016).
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Affiliation(s)
- Brian Dean
- The Molecular Psychiatry Laboratory, The Florey Institute for Neuroscience and Mental Health, Parkville, Victoria, Australia.
| | - David Copolov
- Office of the Vice-Chancellor and President, Monash University, Clayton, Victoria, Australia
| | - Elizabeth Scarr
- The Molecular Psychiatry Laboratory, The Florey Institute for Neuroscience and Mental Health, Parkville, Victoria, Australia
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14
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Nikolaus S, Müller HW, Hautzel H. Different patterns of 5-HT receptor and transporter dysfunction in neuropsychiatric disorders--a comparative analysis of in vivo imaging findings. Rev Neurosci 2016; 27:27-59. [PMID: 26376220 DOI: 10.1515/revneuro-2015-0014] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2015] [Accepted: 08/05/2015] [Indexed: 11/15/2022]
Abstract
Impairment of serotonin receptor and transporter function is increasingly recognized to play a major role in the pathophysiology of neuropsychiatric diseases including anxiety disorder (AD), major depressive disorder (MDD), bipolar disorder (BD) and schizophrenia (SZ). We conducted a PubMed search, which provided a total of 136 in vivo studies with PET and SPECT, in which 5-HT synthesis, 5-HT transporter binding, 5-HT1 receptor binding or 5-HT2 receptor binding in patients with the primary diagnosis of acute AD, MDD, BD or SZ was compared to healthy individuals. A retrospective analysis revealed that AD, MDD, BD and SZ differed as to affected brain region(s), affected synaptic constituent(s) and extent as well as direction of dysfunction in terms of either sensitization or desensitization of transporter and receptor binding sites.
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15
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Schmitt A, Rujescu D, Gawlik M, Hasan A, Hashimoto K, Iceta S, Jarema M, Kambeitz J, Kasper S, Keeser D, Kornhuber J, Koutsouleris N, Lanzenberger R, Malchow B, Saoud M, Spies M, Stöber G, Thibaut F, Riederer P, Falkai P. Consensus paper of the WFSBP Task Force on Biological Markers: Criteria for biomarkers and endophenotypes of schizophrenia part II: Cognition, neuroimaging and genetics. World J Biol Psychiatry 2016; 17:406-28. [PMID: 27311987 DOI: 10.1080/15622975.2016.1183043] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
OBJECTIVES Schizophrenia is a group of severe psychiatric disorders with high heritability but only low odds ratios of risk genes. Despite progress in the identification of pathophysiological processes, valid biomarkers of the disease are still lacking. METHODS This comprehensive review summarises recent efforts to identify genetic underpinnings, clinical and cognitive endophenotypes and symptom dimensions of schizophrenia and presents findings from neuroimaging studies with structural, functional and spectroscopy magnetic resonance imaging and positron emission tomography. The potential of findings to be biomarkers of schizophrenia is discussed. RESULTS Recent findings have not resulted in clear biomarkers for schizophrenia. However, we identified several biomarkers that are potential candidates for future research. Among them, copy number variations and links between genetic polymorphisms derived from genome-wide analysis studies, clinical or cognitive phenotypes, multimodal neuroimaging findings including positron emission tomography and magnetic resonance imaging, and the application of multivariate pattern analyses are promising. CONCLUSIONS Future studies should address the effects of treatment and stage of the disease more precisely and apply combinations of biomarker candidates. Although biomarkers for schizophrenia await validation, knowledge on candidate genomic and neuroimaging biomarkers is growing rapidly and research on this topic has the potential to identify psychiatric endophenotypes and in the future increase insight on individual treatment response in schizophrenia.
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Affiliation(s)
- Andrea Schmitt
- a Department of Psychiatry and Psychotherapy , LMU Munich , Germany ;,b Laboratory of Neuroscience (LIM27), Institute of Psychiatry , University of Sao Paulo , Sao Paulo , Brazil
| | - Dan Rujescu
- c Department of Psychiatry, Psychotherapy and Psychosomatics , University of Halle , Germany
| | - Micha Gawlik
- d Department of Psychiatry, Psychotherapy and Psychosomatics , University of Würzburg , Germany
| | - Alkomiet Hasan
- a Department of Psychiatry and Psychotherapy , LMU Munich , Germany
| | - Kenji Hashimoto
- e Division of Clinical Neuroscience , Chiba University Center for Forensic Mental Health , Chiba , Japan
| | - Sylvain Iceta
- f INSERM, U1028; CNRS, UMR5292; Lyon Neuroscience Research Center, PsyR2 Team , Lyon , F-69000 , France ; Hospices Civils De Lyon, France
| | - Marek Jarema
- g Department of Psychiatry , Institute of Psychiatry and Neurology , Warsaw , Poland
| | - Joseph Kambeitz
- a Department of Psychiatry and Psychotherapy , LMU Munich , Germany
| | - Siegfried Kasper
- h Department of Psychiatry and Psychotherapy , Medical University of Vienna , Austria
| | - Daniel Keeser
- a Department of Psychiatry and Psychotherapy , LMU Munich , Germany
| | - Johannes Kornhuber
- i Department of Psychiatry and Psychotherapy , Friedrich-Alexander-University Erlangen-Nuremberg , Erlangen , Germany
| | | | - Rupert Lanzenberger
- h Department of Psychiatry and Psychotherapy , Medical University of Vienna , Austria
| | - Berend Malchow
- a Department of Psychiatry and Psychotherapy , LMU Munich , Germany
| | - Mohamed Saoud
- f INSERM, U1028; CNRS, UMR5292; Lyon Neuroscience Research Center, PsyR2 Team , Lyon , F-69000 , France ; Hospices Civils De Lyon, France
| | - Marie Spies
- h Department of Psychiatry and Psychotherapy , Medical University of Vienna , Austria
| | - Gerald Stöber
- d Department of Psychiatry, Psychotherapy and Psychosomatics , University of Würzburg , Germany
| | - Florence Thibaut
- j Department of Psychiatry , University Hospital Cochin (Site Tarnier), University of Paris-Descartes, INSERM U 894 Centre Psychiatry and Neurosciences , Paris , France
| | - Peter Riederer
- k Center of Psychic Health; Clinic and Policlinic for Psychiatry, Psychosomatics and Psychotherapy, University Hospital of Wuerzburg , Germany
| | - Peter Falkai
- a Department of Psychiatry and Psychotherapy , LMU Munich , Germany
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16
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Patrich E, Piontkewitz Y, Peretz A, Weiner I, Attali B. Maturation- and sex-sensitive depression of hippocampal excitatory transmission in a rat schizophrenia model. Brain Behav Immun 2016; 51:240-251. [PMID: 26327125 DOI: 10.1016/j.bbi.2015.08.021] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/02/2015] [Revised: 08/20/2015] [Accepted: 08/27/2015] [Indexed: 11/28/2022] Open
Abstract
Schizophrenia is associated with behavioral and brain structural abnormalities, of which the hippocampus appears to be one of the most consistent region affected. Previous studies performed on the poly I:C model of schizophrenia suggest that alterations in hippocampal synaptic transmission and plasticity take place in the offspring. However, these investigations yielded conflicting results and the neurophysiological alterations responsible for these deficits are still unclear. Here we performed for the first time a longitudinal study examining the impact of prenatal poly I:C treatment and of gender on hippocampal excitatory neurotransmission. In addition, we examined the potential preventive/curative effects of risperidone (RIS) treatment during the peri-adolescence period. Excitatory synaptic transmission was determined by stimulating Schaffer collaterals and monitoring fiber volley amplitude and slope of field-EPSP (fEPSP) in CA1 pyramidal neurons in male and female offspring hippocampal slices from postnatal days (PNDs) 18-20, 34, 70 and 90. Depression of hippocampal excitatory transmission appeared at juvenile age in male offspring of the poly I:C group, while it expressed with a delay in female, manifesting at adulthood. In addition, a reduced hippocampal size was found in both adult male and female offspring of poly I:C treated dams. Treatment with RIS at the peri-adolescence period fully restored in males but partly repaired in females these deficiencies. A maturation- and sex-dependent decrease in hippocampal excitatory transmission occurs in the offspring of poly I:C treated pregnant mothers. Pharmacological intervention with RIS during peri-adolescence can cure in a gender-sensitive fashion early occurring hippocampal synaptic deficits.
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Affiliation(s)
- Eti Patrich
- Department of Physiology & Pharmacology, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv 69978, Israel; Department of Psychology, Gordon Faculty of Social Sciences, Tel Aviv University, Tel Aviv 69978, Israel; Sagol School of Neuroscience, Tel Aviv University, Tel Aviv 69978, Israel
| | - Yael Piontkewitz
- Strauss Center for Computational Neuroimaging, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv 69978, Israel
| | - Asher Peretz
- Department of Physiology & Pharmacology, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv 69978, Israel
| | - Ina Weiner
- Department of Psychology, Gordon Faculty of Social Sciences, Tel Aviv University, Tel Aviv 69978, Israel; Sagol School of Neuroscience, Tel Aviv University, Tel Aviv 69978, Israel
| | - Bernard Attali
- Department of Physiology & Pharmacology, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv 69978, Israel; Sagol School of Neuroscience, Tel Aviv University, Tel Aviv 69978, Israel.
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17
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Abstract
Histone modifications and DNA methylation represent central dynamic and reversible processes that regulate gene expression and contribute to cellular phenotypes. These epigenetic marks have been shown to play fundamental roles in a diverse set of signaling and behavioral outcomes. Serotonin is a monoamine that regulates numerous physiological responses including those in the central nervous system. The cardinal signal transduction mechanisms via serotonin and its receptors are well established, but fundamental questions regarding complex interactions between the serotonin system and heritable epigenetic modifications that exert control on gene function remain a topic of intense research and debate. This review focuses on recent advances and contributions to our understanding of epigenetic mechanisms of serotonin receptor-dependent signaling, with focus on psychiatric disorders such as schizophrenia and depression.
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Affiliation(s)
- Terrell Holloway
- Department of Psychiatry, ‡Department of Neurology, and §Friedman Brain Institute, Icahn School of Medicine at Mount Sinai New York, New York 10029, United States
| | - Javier González-Maeso
- Department of Psychiatry, ‡Department of Neurology, and §Friedman Brain Institute, Icahn School of Medicine at Mount Sinai New York, New York 10029, United States
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18
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Knudsen GM, Jensen PS, Erritzoe D, Baaré WFC, Ettrup A, Fisher PM, Gillings N, Hansen HD, Hansen LK, Hasselbalch SG, Henningsson S, Herth MM, Holst KK, Iversen P, Kessing LV, Macoveanu J, Madsen KS, Mortensen EL, Nielsen FÅ, Paulson OB, Siebner HR, Stenbæk DS, Svarer C, Jernigan TL, Strother SC, Frokjaer VG. The Center for Integrated Molecular Brain Imaging (Cimbi) database. Neuroimage 2015; 124:1213-1219. [PMID: 25891375 DOI: 10.1016/j.neuroimage.2015.04.025] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2015] [Revised: 04/08/2015] [Accepted: 04/09/2015] [Indexed: 01/07/2023] Open
Abstract
We here describe a multimodality neuroimaging containing data from healthy volunteers and patients, acquired within the Lundbeck Foundation Center for Integrated Molecular Brain Imaging (Cimbi) in Copenhagen, Denmark. The data is of particular relevance for neurobiological research questions related to the serotonergic transmitter system with its normative data on the serotonergic subtype receptors 5-HT1A, 5-HT1B, 5-HT2A, and 5-HT4 and the 5-HT transporter (5-HTT), but can easily serve other purposes. The Cimbi database and Cimbi biobank were formally established in 2008 with the purpose to store the wealth of Cimbi-acquired data in a highly structured and standardized manner in accordance with the regulations issued by the Danish Data Protection Agency as well as to provide a quality-controlled resource for future hypothesis-generating and hypothesis-driven studies. The Cimbi database currently comprises a total of 1100 PET and 1000 structural and functional MRI scans and it holds a multitude of additional data, such as genetic and biochemical data, and scores from 17 self-reported questionnaires and from 11 neuropsychological paper/computer tests. The database associated Cimbi biobank currently contains blood and in some instances saliva samples from about 500 healthy volunteers and 300 patients with e.g., major depression, dementia, substance abuse, obesity, and impulsive aggression. Data continue to be added to the Cimbi database and biobank.
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Affiliation(s)
- Gitte M Knudsen
- Center for Integrated Molecular Brain Imaging, Copenhagen University Hospital, Rigshospitalet, DK-2100 Copenhagen, Denmark; Neurobiology Research Unit, Copenhagen University Hospital, Rigshospitalet, DK-2100 Copenhagen, Denmark; Faculty of Health and Medical Sciences, University of Copenhagen, DK-2100 Copenhagen, Denmark.
| | - Peter S Jensen
- Center for Integrated Molecular Brain Imaging, Copenhagen University Hospital, Rigshospitalet, DK-2100 Copenhagen, Denmark; Neurobiology Research Unit, Copenhagen University Hospital, Rigshospitalet, DK-2100 Copenhagen, Denmark
| | - David Erritzoe
- Center for Integrated Molecular Brain Imaging, Copenhagen University Hospital, Rigshospitalet, DK-2100 Copenhagen, Denmark; Neurobiology Research Unit, Copenhagen University Hospital, Rigshospitalet, DK-2100 Copenhagen, Denmark
| | - William F C Baaré
- Center for Integrated Molecular Brain Imaging, Copenhagen University Hospital, Rigshospitalet, DK-2100 Copenhagen, Denmark; Danish Research Centre for Magnetic Resonance, Centre for Functional and Diagnostic Imaging and Research, Copenhagen University Hospital Hvidovre, DK-2650 Hvidovre, Denmark
| | - Anders Ettrup
- Center for Integrated Molecular Brain Imaging, Copenhagen University Hospital, Rigshospitalet, DK-2100 Copenhagen, Denmark; Neurobiology Research Unit, Copenhagen University Hospital, Rigshospitalet, DK-2100 Copenhagen, Denmark
| | - Patrick M Fisher
- Center for Integrated Molecular Brain Imaging, Copenhagen University Hospital, Rigshospitalet, DK-2100 Copenhagen, Denmark; Neurobiology Research Unit, Copenhagen University Hospital, Rigshospitalet, DK-2100 Copenhagen, Denmark
| | - Nic Gillings
- Center for Integrated Molecular Brain Imaging, Copenhagen University Hospital, Rigshospitalet, DK-2100 Copenhagen, Denmark; PET and Cyclotron Unit, Copenhagen University Hospital, Rigshospitalet, DK-2100 Copenhagen, Denmark
| | - Hanne D Hansen
- Center for Integrated Molecular Brain Imaging, Copenhagen University Hospital, Rigshospitalet, DK-2100 Copenhagen, Denmark; Neurobiology Research Unit, Copenhagen University Hospital, Rigshospitalet, DK-2100 Copenhagen, Denmark
| | - Lars Kai Hansen
- Center for Integrated Molecular Brain Imaging, Copenhagen University Hospital, Rigshospitalet, DK-2100 Copenhagen, Denmark; DTU Compute, Technical University of Denmark, DK-2800 Kgs. Lyngby, Denmark
| | - Steen G Hasselbalch
- Center for Integrated Molecular Brain Imaging, Copenhagen University Hospital, Rigshospitalet, DK-2100 Copenhagen, Denmark; Neurobiology Research Unit, Copenhagen University Hospital, Rigshospitalet, DK-2100 Copenhagen, Denmark; Faculty of Health and Medical Sciences, University of Copenhagen, DK-2100 Copenhagen, Denmark
| | - Susanne Henningsson
- Center for Integrated Molecular Brain Imaging, Copenhagen University Hospital, Rigshospitalet, DK-2100 Copenhagen, Denmark; Danish Research Centre for Magnetic Resonance, Centre for Functional and Diagnostic Imaging and Research, Copenhagen University Hospital Hvidovre, DK-2650 Hvidovre, Denmark
| | - Matthias M Herth
- Center for Integrated Molecular Brain Imaging, Copenhagen University Hospital, Rigshospitalet, DK-2100 Copenhagen, Denmark; Neurobiology Research Unit, Copenhagen University Hospital, Rigshospitalet, DK-2100 Copenhagen, Denmark; PET and Cyclotron Unit, Copenhagen University Hospital, Rigshospitalet, DK-2100 Copenhagen, Denmark; Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, DK-2100 Copenhagen, Denmark
| | - Klaus K Holst
- Center for Integrated Molecular Brain Imaging, Copenhagen University Hospital, Rigshospitalet, DK-2100 Copenhagen, Denmark; Neurobiology Research Unit, Copenhagen University Hospital, Rigshospitalet, DK-2100 Copenhagen, Denmark; Department of Biostatistics, University of Copenhagen, DK-1014 Copenhagen, Denmark
| | - Pernille Iversen
- Center for Integrated Molecular Brain Imaging, Copenhagen University Hospital, Rigshospitalet, DK-2100 Copenhagen, Denmark; Danish Research Centre for Magnetic Resonance, Centre for Functional and Diagnostic Imaging and Research, Copenhagen University Hospital Hvidovre, DK-2650 Hvidovre, Denmark
| | - Lars V Kessing
- Psychiatric Center Copenhagen, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark; Faculty of Health and Medical Sciences, University of Copenhagen, DK-2100 Copenhagen, Denmark
| | - Julian Macoveanu
- Center for Integrated Molecular Brain Imaging, Copenhagen University Hospital, Rigshospitalet, DK-2100 Copenhagen, Denmark; Danish Research Centre for Magnetic Resonance, Centre for Functional and Diagnostic Imaging and Research, Copenhagen University Hospital Hvidovre, DK-2650 Hvidovre, Denmark; Psychiatric Center Copenhagen, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark
| | - Kathrine Skak Madsen
- Center for Integrated Molecular Brain Imaging, Copenhagen University Hospital, Rigshospitalet, DK-2100 Copenhagen, Denmark; Danish Research Centre for Magnetic Resonance, Centre for Functional and Diagnostic Imaging and Research, Copenhagen University Hospital Hvidovre, DK-2650 Hvidovre, Denmark
| | - Erik L Mortensen
- Department of Public Health and Center for Healthy Aging, University of Copenhagen, DK-2200 Copenhagen, Denmark; Faculty of Health and Medical Sciences, University of Copenhagen, DK-2100 Copenhagen, Denmark
| | - Finn Årup Nielsen
- Center for Integrated Molecular Brain Imaging, Copenhagen University Hospital, Rigshospitalet, DK-2100 Copenhagen, Denmark; DTU Compute, Technical University of Denmark, DK-2800 Kgs. Lyngby, Denmark
| | - Olaf B Paulson
- Center for Integrated Molecular Brain Imaging, Copenhagen University Hospital, Rigshospitalet, DK-2100 Copenhagen, Denmark; Neurobiology Research Unit, Copenhagen University Hospital, Rigshospitalet, DK-2100 Copenhagen, Denmark; Danish Research Centre for Magnetic Resonance, Centre for Functional and Diagnostic Imaging and Research, Copenhagen University Hospital Hvidovre, DK-2650 Hvidovre, Denmark; Faculty of Health and Medical Sciences, University of Copenhagen, DK-2100 Copenhagen, Denmark
| | - Hartwig R Siebner
- Center for Integrated Molecular Brain Imaging, Copenhagen University Hospital, Rigshospitalet, DK-2100 Copenhagen, Denmark; Danish Research Centre for Magnetic Resonance, Centre for Functional and Diagnostic Imaging and Research, Copenhagen University Hospital Hvidovre, DK-2650 Hvidovre, Denmark; Department of Neurology, Copenhagen University Hospital Bispebjerg, DK-2400 Copenhagen, Denmark; Department of Neurology, Copenhagen University Hospital Bispebjerg, DK-2400 Copenhagen, Denmark
| | - Dea S Stenbæk
- Center for Integrated Molecular Brain Imaging, Copenhagen University Hospital, Rigshospitalet, DK-2100 Copenhagen, Denmark; Neurobiology Research Unit, Copenhagen University Hospital, Rigshospitalet, DK-2100 Copenhagen, Denmark
| | - Claus Svarer
- Center for Integrated Molecular Brain Imaging, Copenhagen University Hospital, Rigshospitalet, DK-2100 Copenhagen, Denmark; Neurobiology Research Unit, Copenhagen University Hospital, Rigshospitalet, DK-2100 Copenhagen, Denmark
| | - Terry L Jernigan
- Center for Human Development, University of California, San Diego, La Jolla, CA 92093, USA
| | - Stephen C Strother
- Rotman Research Institute, Baycrest Centre, Toronto, Ontario, Canada; Department of Medical Biophysics, University of Toronto, Toronto, Ontario, Canada
| | - Vibe G Frokjaer
- Center for Integrated Molecular Brain Imaging, Copenhagen University Hospital, Rigshospitalet, DK-2100 Copenhagen, Denmark; Neurobiology Research Unit, Copenhagen University Hospital, Rigshospitalet, DK-2100 Copenhagen, Denmark; Psychiatric Center Copenhagen, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark
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19
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George N, Gean EG, Nandi A, Frolov B, Zaidi E, Lee H, Brašić JR, Wong DF. Advances in CNS Imaging Agents: Focus on PET and SPECT Tracers in Experimental and Clinical Use. CNS Drugs 2015; 29:313-30. [PMID: 25948171 DOI: 10.1007/s40263-015-0237-z] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The physiological functioning of the brain is not well-known in current day medicine and the pathologies of many neuropsychiatric disorders are still not yet fully understood. With our aging population and better life expectancies, it has become imperative to find better biomarkers for disease progression as well as receptor target engagements. In the last decade, these major advances in the field of molecular CNS imaging have been made available with tools such as functional magnetic resonance imaging (fMRI), magnetic resonance spectroscopy (MRS), single photon emission computed tomography (SPECT), and neuroreceptor-targeted positron emission tomography (PET). These tools have given researchers, pharmaceutical companies, and clinical physicians a better method of understanding CNS dysfunctions, and the ability to employ improved therapeutic agents. This review is intended to provide an update on brain imaging agents that are currently used in clinical and translational research toward treatment of CNS disorders. The review begins with amyloid and tau imaging, the former of which has at least three [(18)F] agents that have been recently approved and will soon be available for clinical use for specific indications in the USA and elsewhere. Other prevalent PET and SPECT neurotransmitter system agents, including those newly US FDA-approved imaging agents related to the dopaminergic system, are included. A review of both mature and potentially growing PET imaging agents, including those targeting serotonin and opiate receptor systems, is also provided.
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Affiliation(s)
- Noble George
- The Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins School of Medicine, Johns Hopkins Medical Institutions, 601 N. Caroline St., JHOC Room 3245, Baltimore, MD, 21287-0807, USA
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Dumas N, Moulin-Sallanon M, Ginovart N, Tournier BB, Suzanne P, Cailly T, Fabis F, Rault S, Charnay Y, Millet P. Small-animal single-photon emission computed tomographic imaging of the brain serotoninergic systems in wild-type and mdr1a knockout rats. Mol Imaging 2014; 13. [PMID: 24622810 DOI: 10.2310/7290.2013.00072] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
The pharmacokinetic properties of radiotracers are crucial for successful in vivo single-photon emission computed tomographic (SPECT) imaging. Our goal was to determine if MDR1A-deficient animals could allow better SPECT imaging outcomes than wild-type (WT) animals for a selection of serotoninergic radioligands. Thus, we compared the performances of 123I-p-MPPI, 123I-R91150, 123I-SB207710, and 123I-ADAM radioligands, for imaging of their respective targets (5-hydroxytryptamine [5-HT]1A, 5-HT2A, 5-HT4, and serotonin transporter [SERT]), in WT and Mdr1a knockout (KO) rats. With 123I-SB207710, virtually no SPECT signal was recorded in the brain of WT or KO animals. For 123I-p-MPPI, low nondisplaceable binding potentials (BPND, mean ± SD) were observed in WT (0.49 ± 0.25) and KO (0.89 ± 0.52) animals. For 123I-ADAM, modest imaging contrast was observed in WT (1.27 ± 0.02) and KO (1.31 ± 0.09) animals. For 123I-R91150, the BPND were significantly higher in Mdr1a KO (3.98 ± 0.65) animals compared to WT animals (1.22 ± 0.26). The pharmacokinetics of 123I-SB207710 and 123I-p-MPPI do not make them ideal tracers for preclinical SPECT neuroimaging. 123I-ADAM showed adequate brain uptake regardless of Mdr1a expression and appeared suitable for preclinical SPECT neuroimaging in both animal strains. The use of Mdr1a KO animals significantly improved the brain penetration of 123I-R91150, making this animal strain an interesting option when considering SPECT neuroimaging of 5-HT2A receptors in rat.
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Nikolaus S, Hautzel H, Müller HW. Neurochemical dysfunction in treated and nontreated schizophrenia - a retrospective analysis of in vivo imaging studies. Rev Neurosci 2014; 25:25-96. [PMID: 24486731 DOI: 10.1515/revneuro-2013-0063] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2013] [Accepted: 12/26/2013] [Indexed: 12/22/2022]
Abstract
To evaluate the contribution of individual synaptic constituents, all available in vivo imaging studies on schizophrenic patients were subjected to a retrospective analysis. For the pool of drug-naïve, drug-free, and acutely medicated patients, major findings were increases in neostriatal dopamine (DA) synthesis and release and decreases in neostriatal DA transporters and D1 receptors, neostriatal, thalamic, frontal, and parietal D2 receptors, mesencephalic/pontine and temporal 5-HT1A receptors, frontal and temporal HT2A and μ-amino butyric acid (GABA)A receptors. Based on the findings on drug-naïve and drug-free patients, it may be hypothesized that schizophrenia initially is characterized by an impaired mechanism of D2 autoreceptor and heteroreceptor sensitization leading to sensitization instead of desensitization in response to increased levels of neostriatal DA. Neuroleptic medication blocks neostriatal D2 autoreceptor and heteroreceptors, reducing neostriatal DA and disinhibiting DA action mediated by D2 heteroreceptor binding sites. Ultimately, this may result in a restitution of GABA function, leading to a recovery of inhibitory input to the target regions of the descending corticothalamostriatal efferents. Furthermore, a blockade of inhibitory and excitatory neocortical 5-HT function may be inferred, which is likely to reduce (excitatory) DAergic input to the mesolimbic target regions of corticothalamostriatal projections.
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Vyas NS, Patel NH, Nijran KS, Al-Nahhas A, Puri BK. The use of PET imaging in studying cognition, genetics and pharmacotherapeutic interventions in schizophrenia. Expert Rev Neurother 2014; 11:37-51. [DOI: 10.1586/ern.10.160] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
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Abstract
One of the oldest models of schizophrenia is based on the effects of serotonergic hallucinogens such as mescaline, psilocybin, and (+)-lysergic acid diethylamide (LSD), which act through the serotonin 5-HT(2A) receptor. These compounds produce a 'model psychosis' in normal individuals that resembles at least some of the positive symptoms of schizophrenia. Based on these similarities, and because evidence has emerged that the serotonergic system plays a role in the pathogenesis of schizophrenia in some patients, animal models relevant to schizophrenia have been developed based on hallucinogen effects. Here we review the behavioural effects of hallucinogens in four of those models, the receptor and neurochemical mechanisms for the effects and their translational relevance. Despite the difficulty of modelling hallucinogen effects in nonverbal species, animal models of schizophrenia based on hallucinogens have yielded important insights into the linkage between 5-HT and schizophrenia and have helped to identify receptor targets and interactions that could be exploited in the development of new therapeutic agents.
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Chana G, Bousman CA, Money TT, Gibbons A, Gillett P, Dean B, Everall IP. Biomarker investigations related to pathophysiological pathways in schizophrenia and psychosis. Front Cell Neurosci 2013; 7:95. [PMID: 23805071 PMCID: PMC3693064 DOI: 10.3389/fncel.2013.00095] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2013] [Accepted: 06/03/2013] [Indexed: 12/28/2022] Open
Abstract
Post-mortem brain investigations of schizophrenia have generated swathes of data in the last few decades implicating candidate genes and protein. However, the relation of these findings to peripheral biomarker indicators and symptomatology remain to be elucidated. While biomarkers for disease do not have to be involved with underlying pathophysiology and may be largely indicative of diagnosis or prognosis, the ideal may be a biomarker that is involved in underlying disease processes and which is therefore more likely to change with progression of the illness as well as potentially being more responsive to treatment. One of the main difficulties in conducting biomarker investigations for major psychiatric disorders is the relative inconsistency in clinical diagnoses between disorders such as bipolar and schizophrenia. This has led some researchers to investigate biomarkers associated with core symptoms of these disorders, such as psychosis. The aim of this review is to evaluate the contribution of post-mortem brain investigations to elucidating the pathophysiology pathways involved in schizophrenia and psychosis, with an emphasis on major neurotransmitter systems that have been implicated. This data will then be compared to functional neuroimaging findings as well as findings from blood based gene expression investigations in schizophrenia in order to highlight the relative overlap in pathological processes between these different modalities used to elucidate pathogenesis of schizophrenia. In addition we will cover some recent and exciting findings demonstrating microRNA (miRNA) dysregulation in both the blood and the brain in patients with schizophrenia. These changes are pertinent to the topic due to their known role in post-transcriptional modification of gene expression with the potential to contribute or underlie gene expression changes observed in schizophrenia. Finally, we will discuss how post-mortem studies may aid future biomarker investigations.
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Affiliation(s)
- Gursharan Chana
- Department of Psychiatry, Melbourne Brain Centre, The University of Melbourne Parkville, VIC, Australia
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25
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Delille HK, Mezler M, Marek GJ. The two faces of the pharmacological interaction of mGlu2 and 5-HT₂A - relevance of receptor heterocomplexes and interaction through functional brain pathways. Neuropharmacology 2013; 70:296-305. [PMID: 23466331 DOI: 10.1016/j.neuropharm.2013.02.005] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2012] [Revised: 02/01/2013] [Accepted: 02/04/2013] [Indexed: 11/28/2022]
Abstract
Important functional interactions between the metabotropic glutamate 2 (mGlu2) and 5-hydroxytryptamine2A (5-HT₂A) neurotransmitter receptors have been established based on electrophysiological, biochemical and behavioral evidence. Over the last several years, dimerization between 5-HT₂A and mGlu2 receptors has been proposed to account for the functional cross-talk between these two receptors in the prefrontal cortex. The pros and cons for the existence of a heteromeric complex between 5-HT₂A and mGlu2 receptors will be reviewed here. First, the fundamental criteria needing to establish evidence for heteromeric complexes will be reviewed. Then, the in vitro evidence for and against heteromeric complexes between 5-HT₂A and mGlu2 receptors will be discussed in regard to physical and functional interactions. Finally, the data with native in situ mGlu2 and 5-HT₂A receptors will be discussed with respect to whether heteromeric complexes or a simple functional interaction between two distinct GPCRs based on brain network activity is the more simple explanation for a range of in vivo data.
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Affiliation(s)
- Hannah K Delille
- Abbott Diagnostics Division, Max-Planck-Ring 2, 65205 Wiesbaden, Germany
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Transmembrane domain Nrg1 mutant mice show altered susceptibility to the neurobehavioural actions of repeated THC exposure in adolescence. Int J Neuropsychopharmacol 2013; 16:163-75. [PMID: 22226049 DOI: 10.1017/s1461145711001854] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Heavy cannabis abuse increases the risk of developing schizophrenia. Adolescents appear particularly vulnerable to the development of psychosis-like symptoms after cannabis use. To test whether the schizophrenia candidate gene neuregulin 1 (NRG1) modulates the effects of cannabinoids in adolescence, we tested male adolescent heterozygous transmembrane domain Nrg1 mutant (Nrg1 TM HET) mice and wild type-like littermates (WT) for their neurobehavioural response to repeated Δ(9)-tetrahydrocannabinol (THC, 10 mg/kg i.p. for 21 d starting on post-natal day 31). During treatment and 48 h after treatment withdrawal, we assessed several behavioural parameters relevant to schizophrenia. After behavioural testing we measured autoradiographic CB(1), 5-HT(2A) and NMDA receptor binding. The hyperlocomotor phenotype typical of Nrg1 mutants emerged after drug withdrawal and was more pronounced in vehicle than THC-treated Nrg1 TM HET mice. All mice were equally sensitive to THC-induced suppression of locomotion. However, mutant mice appeared protected against inhibiting effects of repeated THC on investigative social behaviours. Neither THC nor Nrg1 genotype altered prepulse inhibition. Repeated adolescent THC promoted differential effects on CB(1) and 5-HT(2A) receptor binding in the substantia nigra and insular cortex respectively, decreasing binding in WT while increasing it in Nrg1 TM HET mice. THC also selectively affected 5-HT(2A) receptor binding in several other regions in WT mice, whereas NMDA receptor binding was only affected in mutant mice. Overall, Nrg1 mutation does not appear to increase the induction of psychotomimetic symptoms by repeated adolescent THC exposure but may attenuate some of its actions on social behaviour and schizophrenia-relevant neurotransmitter receptor profiles.
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Meltzer HY, Elkis H, Vanover K, Weiner DM, van Kammen DP, Peters P, Hacksell U. Pimavanserin, a selective serotonin (5-HT)2A-inverse agonist, enhances the efficacy and safety of risperidone, 2mg/day, but does not enhance efficacy of haloperidol, 2mg/day: comparison with reference dose risperidone, 6mg/day. Schizophr Res 2012; 141:144-52. [PMID: 22954754 DOI: 10.1016/j.schres.2012.07.029] [Citation(s) in RCA: 73] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/16/2012] [Revised: 07/25/2012] [Accepted: 07/27/2012] [Indexed: 12/25/2022]
Abstract
Most atypical antipsychotic drugs (APDs), e.g. risperidone (RIS), produce more extensive blockade of brain serotonin (5-HT)(2A) than dopamine (DA) D(2) receptors. This distinguishes them from typical APDs, e.g. haloperidol (HAL). Our objective was to test the hypothesis that augmentation of low doses of RIS or HAL (2mg/day) with pimavanserin (PIM), a selective 5-HT(2A) inverse agonist, to enhance 5-HT(2A) receptor blockade, can achieve efficacy comparable to RIS, 6mg/day, but with lesser side effects. In a multi-center, randomized, double-blind, 6week trial, 423 patients with chronic schizophrenia experiencing a recent exacerbation of psychotic symptoms were randomized to RIS2mg+placebo (RIS2PBO), RIS2mg+PIM20mg (RIS2PIM), RIS6mg+PBO (RIS6PBO), HAL2mg+PBO (HAL2PBO), or HAL2mg+PIM20mg (HAL2PIM). Improvement in psychopathology was measured by the PANSS and CGI-S. The reduction in PANSS Total Score with RIS2PIM at endpoint was significantly greater than RIS2PBO: -23.0 vs. -16.3 (p=0.007), and not significantly different from the RIS6PBO group: -23.2 points. The percentage of patients with ≥20% improvement at day 15 in the RIS2PIM group was 62.3%, significantly greater than the RIS6PBO (42.1%; p=0.01) and the RIS2PBO groups (37.7%; p=0.002). Weight gain and hyperprolactinemia were greater in the RIS6PBO group than the RIS2PIM group but there was no difference in extrapyramidal side effects (EPS). HAL2PBO and HAL2PIM were not significantly different from each other in efficacy but HAL2PIM had less EPS at end point. Both HAL groups and RIS6PBO showed equal improvement in psychopathology at endpoint, indicating HAL 2mg/day is effective to treat an acute exacerbation in chronic schizophrenia patients. In conclusion, a sub-effective RIS dose combined with PIM to enhance 5-HT(2A) receptor blockade provided faster onset of action, and at endpoint, equal efficacy and better safety, compared to standard dose RIS. These results support the conclusion that 5-HT(2A) receptor blockade is a key component of the action of some atypical APDs and can reduce EPS due to a typical APD.
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Affiliation(s)
- Herbert Y Meltzer
- Department of Psychiatry and Behavioral Sciences, Northwestern Feinberg School of Medicine, Ward Bldg 12-104, 303 East Chicago Ave. Chicago, Il 60611, USA.
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Howes OD, Fusar-Poli P, Bloomfield M, Selvaraj S, McGuire P. From the prodrome to chronic schizophrenia: the neurobiology underlying psychotic symptoms and cognitive impairments. Curr Pharm Des 2012; 18:459-65. [PMID: 22239576 DOI: 10.2174/138161212799316217] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2011] [Accepted: 10/18/2011] [Indexed: 11/22/2022]
Abstract
Schizophrenia is a chronic psychotic disorder that remains a considerable cause of global disease burden. Cognitive impairments are common and contribute significantly to the morbidity of the disorder. Over the last two decades or so molecular imaging studies have refined understanding of the pathophysiology underlying the development of psychosis and cognitive impairments. Firstly they have consistently implicated presynaptic dopaminergic dysfunction in the disorder, finding that dopamine synthesis capacity, dopamine release and baseline dopamine levels are increased in the illness. Secondly recent findings show that dopamine synthesis capacity is elevated in those that go on to develop psychosis in the following year, but not in those that do not, and appears to increase further with the development of psychosis. Thirdly evidence links greater dopamine synthesis capacity to poorer cognitive performance and altered frontal cortical function measured using functional imaging during cognitive tasks. Finally they have provided data on the nature of other neurofunctional alterations in the disorder, in particular in the serotonergic system and neuroinflammation. We review these findings and discuss their implications for understanding the neurobiology of psychosis and cognitive impairments in schizophrenia.
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Affiliation(s)
- O D Howes
- Psychiatric Imaging Group Cyclotron Building Hammersmith Hospital, London W12 0NN, UK.
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29
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Narayanaswamy JC, Venkatasubramanian G, Gangadhar BN. Neuroimaging studies in schizophrenia: an overview of research from Asia. Int Rev Psychiatry 2012; 24:405-16. [PMID: 23057977 DOI: 10.3109/09540261.2012.704872] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Neuroimaging studies in schizophrenia help clarify the neural substrates underlying the pathogenesis of this neuropsychiatric disorder. Contemporary brain imaging in schizophrenia is predominated by magnetic resonance imaging (MRI)-based research approaches. This review focuses on the various imaging studies from India and their relevance to the understanding of brain abnormalities in schizophrenia. The existing studies are predominantly comprised of structural MRI reports involving region-of-interest and voxel-based morphometry approaches, magnetic resonance spectroscopy and single-photon emission computed tomography/positron emission tomography (SPECT/PET) studies. Most of these studies are significant in that they have evaluated antipsychotic-naïve schizophrenia patients--a relatively difficult population to obtain in contemporary research. Findings of these studies offer robust support to the existence of significant brain abnormalities at very early stages of the disorder. In addition, theoretically relevant relationships between these brain abnormalities and developmental aberrations suggest possible neurodevelopmental basis for these brain deficits.
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Affiliation(s)
- Janardhanan C Narayanaswamy
- Schizophrenia Clinic, Department of Psychiatry, Translational Psychiatry Laboratory, Neurobiology Research Centre, National Institute of Mental Health and Neurosciences, Bangalore, India
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Williams AA, Ingram WM, Levine S, Resnik J, Kamel CM, Lish JR, Elizalde DI, Janowski SA, Shoker J, Kozlenkov A, González-Maeso J, Gallitano AL. Reduced levels of serotonin 2A receptors underlie resistance of Egr3-deficient mice to locomotor suppression by clozapine. Neuropsychopharmacology 2012; 37:2285-98. [PMID: 22692564 PMCID: PMC3422493 DOI: 10.1038/npp.2012.81] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/22/2011] [Revised: 04/06/2012] [Accepted: 04/26/2012] [Indexed: 02/06/2023]
Abstract
The immediate-early gene early growth response 3 (Egr3) is associated with schizophrenia and expressed at reduced levels in postmortem patients' brains. We have previously reported that Egr3-deficient (Egr3(-/-)) mice display reduced sensitivity to the sedating effects of clozapine compared with wild-type (WT) littermates, paralleling the heightened tolerance of schizophrenia patients to antipsychotic side effects. In this study, we have used a pharmacological dissection approach to identify a neurotransmitter receptor defect in Egr3(-/-) mice that may mediate their resistance to the locomotor suppressive effects of clozapine. We report that this response is specific to second-generation antipsychotic agents (SGAs), as first-generation medications suppress the locomotor activity of Egr3(-/-) and WT mice to a similar degree. Further, in contrast to the leading theory that sedation by clozapine results from anti-histaminergic effects, we show that H1 histamine receptors are not responsible for this effect in C57BL/6 mice. Instead, selective serotonin 2A receptor (5HT(2A)R) antagonists ketanserin and MDL-11939 replicate the effect of SGAs, repressing the activity in WT mice at a dosage that fails to suppress the activity of Egr3(-/-) mice. Radioligand binding revealed nearly 70% reduction in 5HT(2A)R expression in the prefrontal cortex of Egr3(-/-) mice compared with controls. Egr3(-/-) mice also exhibit a decreased head-twitch response to 5HT(2A)R agonist 1-(2,5-dimethoxy 4-iodophenyl)-2-amino propane (DOI). These findings provide a mechanism to explain the reduced sensitivity of Egr3(-/-) mice to the locomotor suppressive effects of SGAs, and suggest that 5HT(2A)Rs may also contribute to the sedating properties of these medications in humans. Moreover, as the deficit in cortical 5HT(2A)R in Egr3(-/-) mice aligns with numerous studies reporting decreased 5HT(2A)R levels in the brains of schizophrenia patients, and the gene encoding the 5HT(2A)R is itself a leading schizophrenia candidate gene, these findings suggest a potential mechanism by which putative dysfunction in EGR3 in humans may influence risk for schizophrenia.
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Affiliation(s)
| | - Wendy M Ingram
- Department of Molecular and Cell Biology, Life Sciences Addition, University of California, Berkeley, CA, USA
| | - Sarah Levine
- University of Arizona College of Medicine—Tucson, Tucson, AZ, USA
| | - Jack Resnik
- Department of Basic Medical Sciences and Psychiatry, University of Arizona College of Medicine—Phoenix, Phoenix, AZ, USA
| | - Christy M Kamel
- Department of Basic Medical Sciences and Psychiatry, University of Arizona College of Medicine—Phoenix, Phoenix, AZ, USA
| | - James R Lish
- Department of Basic Medical Sciences and Psychiatry, University of Arizona College of Medicine—Phoenix, Phoenix, AZ, USA
| | - Diana I Elizalde
- Department of Basic Medical Sciences and Psychiatry, University of Arizona College of Medicine—Phoenix, Phoenix, AZ, USA
| | - Scott A Janowski
- University of Arizona College of Medicine—Tucson, Tucson, AZ, USA
| | - Joseph Shoker
- Department of Basic Medical Sciences and Psychiatry, University of Arizona College of Medicine—Phoenix, Phoenix, AZ, USA
| | - Alexey Kozlenkov
- Department of Psychiatry, Mount Sinai School of Medicine, New York, NY, USA
| | - Javier González-Maeso
- Department of Psychiatry, Mount Sinai School of Medicine, New York, NY, USA
- Department of Neurology, Mount Sinai School of Medicine, New York, NY, USA
| | - Amelia L Gallitano
- Department of Basic Medical Sciences and Psychiatry, University of Arizona College of Medicine—Phoenix, Phoenix, AZ, USA
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Abi-Dargham A, Xu X, Thompson JL, Gil R, Kegeles LS, Urban N, Narendran R, Hwang DR, Laruelle M, Slifstein M. Increased prefrontal cortical D₁ receptors in drug naive patients with schizophrenia: a PET study with [¹¹C]NNC112. J Psychopharmacol 2012; 26:794-805. [PMID: 21768159 DOI: 10.1177/0269881111409265] [Citation(s) in RCA: 103] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
D₁ receptors are the main mediators of dopamine transmission in the cortex and subserve cognitive functions that are affected in patients with schizophrenia. Prior imaging studies have suggested abnormalities in the expression of these receptors in schizophrenia, but no conclusive picture has emerged yet. One source of discrepancy may have been prior antipsychotic exposure. We used positron emission tomography (PET) and a D1 radiotracer, [¹¹C]NNC112, in drug naïve (DN, n = 12) and drug free (DF, n = 13) patients with schizophrenia and 40 healthy control subjects (HC, n = 40 total, n = 24 per comparison group) matched for age, gender, ethnicity, parental socioeconomic status and cigarette smoking. We measured the binding potential BPP, corrected for partial volume effects. The outcome measure was obtained in cortical and striatal subregions outlined on coregistered individual MRIs. Partial volume effect corrected BPP measures were significantly higher in DN vs controls in cortical regions. No such increases were found in the DF versus controls comparison. Furthermore, in the DF group, DF interval correlated positively with cortical BPP. We conclude that upregulation of D1 receptors in schizophrenia is related to the illness itself and may be corrected and normalized by chronic antipsychotic treatment.
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Affiliation(s)
- Anissa Abi-Dargham
- Department of Psychiatry, Columbia University College of Physicians and Surgeons, New York, NY 10032, USA.
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Abstract
The results of imaging studies have played an important role in the formulation of hypotheses regarding the etiology of psychosis and schizophrenia, as well as in our understanding of the mechanisms of action of antipsychotics. Since this volume is primarily directed to molecular aspects of psychosis and antipsychotics, only the results of molecular imaging techniques addressing these topics will be discussed here.One of the most consistent findings of molecular imaging studies in schizophrenia is an increased uptake of DOPA in the striatum, which may be interpreted as an increased synthesis of L-DOPA. Also, several studies reported an increased release of dopamine induced by amphetamine in schizophrenia patients. These findings played an important role in reformulating the dopamine hypothesis of schizophrenia. To study the roles of the neurotransmitters γ-aminobutyric acid (GABA) and glutamate in schizophrenia, SPECT as well as MR spectroscopy have been used. The results of preliminary SPECT studies are consistent with the hypothesis of NMDA receptor dysfunction in schizophrenia. Regarding the GABA deficit hypothesis of schizophrenia, imaging results are inconsistent. No changes in serotonin transporters were demonstrated in imaging studies in schizophrenia, but studies of several serotonin receptors showed conflicting results. The lack of selective radiotracers for muscarinic receptors may have hampered examination of this system in schizophrenia as well as its role in the induction of side effects of antipsychotics. Interestingly, preliminary molecular imaging studies on the cannabinoid-1 receptor and on neuroinflammatory processes in schizophrenia have recently been published. Finally, a substantial number of PET/SPECT studies have examined the occupancy of receptors by antipsychotics and an increasing number of studies is now focusing on the effects of these drugs using techniques like spectroscopy and pharmacological MRI.
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Saulin A, Savli M, Lanzenberger R. Serotonin and molecular neuroimaging in humans using PET. Amino Acids 2011; 42:2039-57. [PMID: 21947614 DOI: 10.1007/s00726-011-1078-9] [Citation(s) in RCA: 67] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2011] [Accepted: 09/05/2011] [Indexed: 02/07/2023]
Abstract
The serotonergic system is one of the most important modulatory neurotransmitter systems in the human brain. It plays a central role in major physiological processes and is implicated in a number of psychiatric disorders. Along with the dopaminergic system, it is also one of the phylogenetically oldest human neurotransmitter systems and one of the most diverse, with 14 different receptors identified up to this day, many of whose function remains to be understood. The system's functioning is even more diverse than the number of its receptors, since each is implicated in a number of different processes. This review aims at illustrating the distribution and summarizing the main functions of the serotonin (5-hydroxytryptamin, 5-HT) receptors as well as the serotonin transporter (SERT, 5-HTT), the vesicular monoamine transporter 2, monoamine oxidase type A and 5-HT synthesis in the human brain. Recent advances in in vivo quantification of these different receptors and enzymes that are part of the serotonergic system using positron emission tomography are described.
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Affiliation(s)
- Anne Saulin
- Department of Psychiatry and Psychotherapy, Medical University of Vienna, Waehringer Guertel 18-20, 1090, Vienna, Austria
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Ebdrup BH, Rasmussen H, Arnt J, Glenthøj B. Serotonin 2A receptor antagonists for treatment of schizophrenia. Expert Opin Investig Drugs 2011; 20:1211-23. [PMID: 21740279 DOI: 10.1517/13543784.2011.601738] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
INTRODUCTION All approved antipsychotic drugs share an affinity for the dopamine 2 (D(2)) receptor; however, these drugs only partially ameliorate the symptoms of schizophrenia. It is, therefore, of paramount importance to identify new treatment strategies for schizophrenia. AREAS COVERED Preclinical, clinical and post-mortem studies of the serotonin 5-HT(2A) system in schizophrenia are reviewed. The implications of a combined D(2) and 5-HT(2A) receptor blockade, which is obtained by several current antipsychotic drugs, are discussed, and the rationale for the development of more selective 5-HT(2A) receptor antagonists is evaluated. Moreover, the investigational pipeline of major pharmaceutical companies is examined and an Internet search conducted to identify other pharmaceutical companies investigating 5-HT(2A) receptor antagonists for the treatment of schizophrenia. EXPERT OPINION 5-HT(2A) receptor antagonists appear to assume an intermediate position by being marginally superior to placebo but inferior to conventional antipsychotic drugs. Three previous 5-HT(2A) receptor antagonists have been discontinued after Phase II or III trials, and available Phase IIa data on the remaining 5-HT(2A) receptor antagonist will need substantial additional validation to be approved as a new treatment strategy against schizophrenia.
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Affiliation(s)
- Bjørn H Ebdrup
- Center for Neuropsychiatric Schizophrenia Research, Copenhagen University Hospital Glostrup, Faculty of Health Sciences, Psychiatric Center Glostrup, Nordre Ringvej 29, DK-2600 Glostrup, Denmark
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Schmitt U, Lee DE, Herth MM, Piel M, Buchholz HG, Roesch F, Hiemke C, Lueddens H, Debus F. P-glycoprotein influence on the brain uptake of a 5-HT(2A) ligand: [(18)F]MH.MZ. Neuropsychobiology 2011; 63:183-90. [PMID: 21304228 DOI: 10.1159/000321594] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/26/2010] [Accepted: 09/27/2010] [Indexed: 11/19/2022]
Abstract
BACKGROUND/AIMS The serotonergic system, especially the 5-HT(2A) receptor, is involved in various diseases and conditions. We have recently developed a new [(18)F]-5-HT(2A) receptor ligand using an analogue, MDL 100907, as a basis for molecular imaging with positron emission tomography. This tracer, [(18)F]MH.MZ, has been shown to be an adequate tool to visualize the 5-HT(2A) receptors in vivo. However, [(18)F]altanserin, similar in chemical structure, is a substrate of efflux transporters, such as P-glycoprotein (P-gp), of the blood-brain barrier, thus limiting its availability in the central nervous system. The aim of this study was to determine whether transport by P-gp influences the distribution ratio of [(18)F]MH.MZ in the frontal cortex. METHODS The approach was based on P-gp knockout mice which were compared with wild-type mice under several conditions. In vivo pharmacokinetic and microPET investigations were carried out. RESULTS All analyses showed that [(18)F]MH.MZ entered the brain and was sensitive to P-gp transport. In P-gp knockout mice, brain concentrations of MH.MZ were about 5-fold higher than in wild-type animals which is reflected by a 2-fold increase in standardized uptake values of [(18)F]MH.MZ in the frontal cortex of P-gp knockout mice. CONCLUSION Our results give evidence for a functional role of transport mechanisms at the blood-brain barrier, specifically of P-gp, and its subregional distribution. Investigation of these mechanisms will benefit the development of more efficient radioligands and drugs for molecular imaging and pharmacotherapy of the mentally ill.
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Affiliation(s)
- Ulrich Schmitt
- Institute of Nuclear Chemistry, Johannes Gutenberg University Mainz, Mainz, Germany.
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Paterson LM, Kornum BR, Nutt DJ, Pike VW, Knudsen GM. 5-HT radioligands for human brain imaging with PET and SPECT. Med Res Rev 2011; 33:54-111. [PMID: 21674551 DOI: 10.1002/med.20245] [Citation(s) in RCA: 119] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
The serotonergic system plays a key modulatory role in the brain and is the target for many drug treatments for brain disorders either through reuptake blockade or via interactions at the 14 subtypes of 5-HT receptors. This review provides the history and current status of radioligands used for positron emission tomography (PET) and single photon emission computerized tomography (SPECT) imaging of human brain serotonin (5-HT) receptors, the 5-HT transporter (SERT), and 5-HT synthesis rate. Currently available radioligands for in vivo brain imaging of the 5-HT system in humans include antagonists for the 5-HT(1A), 5-HT(1B), 5-HT(2A), and 5-HT(4) receptors, and for SERT. Here we describe the evolution of these radioligands, along with the attempts made to develop radioligands for additional serotonergic targets. We describe the properties needed for a radioligand to become successful and the main caveats. The success of a PET or SPECT radioligand can ultimately be assessed by its frequency of use, its utility in humans, and the number of research sites using it relative to its invention date, and so these aspects are also covered. In conclusion, the development of PET and SPECT radioligands to image serotonergic targets is of high interest, and successful evaluation in humans is leading to invaluable insight into normal and abnormal brain function, emphasizing the need for continued development of both SPECT and PET radioligands for human brain imaging.
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Affiliation(s)
- Louise M Paterson
- Neuropsychopharmacology Unit, Division of Experimental Medicine, Imperial College London, Burlington Danes Building, Du Cane Road, London, United Kingdom
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In Vitro and Initial In Vivo Evaluation of 68Ga-Labeled Transferrin Receptor (TfR) Binding Peptides as Potential Carriers for Enhanced Drug Transport into TfR Expressing Cells. Mol Imaging Biol 2010; 13:332-41. [DOI: 10.1007/s11307-010-0329-6] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Quednow BB, Geyer MA, Halberstadt AL. Serotonin and Schizophrenia. ACTA ACUST UNITED AC 2010. [DOI: 10.1016/s1569-7339(10)70102-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/29/2023]
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Abstract
Recent advances in the development and applications of neurochemical brain imaging methods have improved the ability to study the neurochemistry of the living brain in normal processes as well as psychiatric disorders. In particular, positron emission tomography (PET) and single photon emission computed tomography (SPECT) have been used to determine neurochemical substrates of schizophrenia and to uncover the mechanism of action of antipsychotic medications. The growing availability of radiotracers for monoaminergic neurotransmitter synthesis, transporters and receptors, has enabled the evaluation of hypotheses regarding neurotransmitter function in schizophrenia derived from preclinical and clinical observations. This chapter reviews the studies using neurochemical brain imaging methods for (1) detection of abnormalities in indices of dopamine and serotonin transmission in patients with schizophrenia compared to controls, (2) development of new tools to study other neurotransmitters systems, such as gamma-aminobutyric acid (GABA) and glutamate, and (3) characterization of target occupancy by antipsychotic drugs, as well as its relationship to efficacy and side effects. As more imaging tools become available, this knowledge will expand and will lead to better detection of disease, as well as better therapeutic approaches.
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Affiliation(s)
- Nina Urban
- Department of Psychiatry, New York State Psychiatric Institute, Columbia University, New York, NY 10032, USA.
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Nikolaus S, Antke C, Müller HW. In vivo imaging of synaptic function in the central nervous system: II. Mental and affective disorders. Behav Brain Res 2009; 204:32-66. [DOI: 10.1016/j.bbr.2009.06.009] [Citation(s) in RCA: 91] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2009] [Revised: 05/27/2009] [Accepted: 06/02/2009] [Indexed: 10/20/2022]
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Thompson JL, Urban N, Abi-Dargham A. How have developments in molecular imaging techniques furthered schizophrenia research? ACTA ACUST UNITED AC 2009; 1:135-153. [PMID: 21243081 DOI: 10.2217/iim.09.22] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Molecular imaging techniques have led to significant advances in understanding the pathophysiology of schizophrenia and contributed to knowledge regarding potential mechanisms of action of the drugs used to treat this illness. The aim of this article is to provide a review of the major findings related to the application of molecular imaging techniques that have furthered schizophrenia research. This article focuses specifically on neuroreceptor imaging studies with PET and SPECT. After providing a brief overview of neuroreceptor imaging methodology, we consider relevant findings from studies of receptor availability, and dopamine synthesis and release. Results are discussed in the context of current hypotheses regarding neurochemical alterations in the illness. We then selectively review pharmacological occupancy studies and the role of neuroreceptor imaging in drug development for schizophrenia.
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Affiliation(s)
- Judy L Thompson
- Department of Psychiatry, Columbia University and New York State Psychiatric Institute, 1051 Riverside Drive, Unit 31, New York, NY 10032, USA
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Kang K, Huang XF, Wang Q, Deng C. Decreased density of serotonin 2A receptors in the superior temporal gyrus in schizophrenia--a postmortem study. Prog Neuropsychopharmacol Biol Psychiatry 2009; 33:867-71. [PMID: 19389456 DOI: 10.1016/j.pnpbp.2009.04.010] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/17/2008] [Revised: 03/17/2009] [Accepted: 04/10/2009] [Indexed: 10/20/2022]
Abstract
The superior temporal gyrus (STG) is strongly implicated in the pathophysiology of schizophrenia, particularly with regards to auditory hallucinations. In this study, using in situ quantitative autoradiography in postmortem tissue, we investigated the binding of the [3H]ketanserin to 5-HT(2A) receptors and [3H]mesulergine to 5-HT(2C) receptors in the left STG of 8 male schizophrenic patients compared to 8 control subjects. A strong [3H]ketanserin binding was observed in the STG, however there was a very weak [3H]mesulergine binding in the STG. A significant decrease in binding of [(3)H]ketanserin was clearly observed in schizophrenia patients in comparison with control subjects. There were no significant correlations between 5-HT(2A) binding density and age, postmortem intervals, or brain pH. These results suggest that the alterations of the 5-HT(2A) receptors contribute to the pathophysiology of the STG in schizophrenia. Furthermore, there is a clear tendency for a positive correlation between 5-HT(2A) and muscarinic M1 receptor bindings, and for negative correlations between 5-HT(2A) and GABA(A) receptor bindings and between muscarinic M1 and GABA(A) receptor bindings. This provides a possible mechanism of auditory hallucinations through interactions between 5-HT(2A), acetylcholine muscarinic and GABA transmissions in the STG in schizophrenia.
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Affiliation(s)
- Kai Kang
- Centre for Translational Neuroscience, School of Health Sciences, University of Wollongong, Wollongong, NSW 2522, Australia
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González-Maeso J, Sealfon SC. Psychedelics and schizophrenia. Trends Neurosci 2009; 32:225-32. [PMID: 19269047 DOI: 10.1016/j.tins.2008.12.005] [Citation(s) in RCA: 112] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2008] [Revised: 12/09/2008] [Accepted: 12/10/2008] [Indexed: 02/08/2023]
Abstract
Research on psychedelics such as lysergic acid diethylamide (LSD) and dissociative drugs such as phencyclidine (PCP) and the symptoms, neurochemical abnormalities and treatment of schizophrenia have converged. The effects of hallucinogenic drugs resemble some of the core symptoms of schizophrenia. Some atypical antipsychotic drugs were identified by their high affinity for serotonin 5-HT(2A) receptors, which is also the target of LSD-like drugs. Several effects of PCP-like drugs are strongly affected by both 5-HT(2A) and metabotropic glutamate 2/3 receptor modulation. A serotonin-glutamate receptor complex in cortical pyramidal neurons has been identified that might be the target both of psychedelics and the atypical and glutamate classes of antipsychotic drugs. Recent results on the receptor, signalling and circuit mechanisms underlying the response to psychedelic and antipsychotic drugs might lead to unification of the serotonin and glutamate neurochemical hypotheses of schizophrenia.
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