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Dopamine Dynamics and Neurobiology of Non-Response to Antipsychotics, Relevance for Treatment Resistant Schizophrenia: A Systematic Review and Critical Appraisal. Biomedicines 2023; 11:biomedicines11030895. [PMID: 36979877 PMCID: PMC10046109 DOI: 10.3390/biomedicines11030895] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2023] [Revised: 03/08/2023] [Accepted: 03/12/2023] [Indexed: 03/17/2023] Open
Abstract
Treatment resistant schizophrenia (TRS) is characterized by a lack of, or suboptimal response to, antipsychotic agents. The biological underpinnings of this clinical condition are still scarcely understood. Since all antipsychotics block dopamine D2 receptors (D2R), dopamine-related mechanisms should be considered the main candidates in the neurobiology of antipsychotic non-response, although other neurotransmitter systems play a role. The aims of this review are: (i) to recapitulate and critically appraise the relevant literature on dopamine-related mechanisms of TRS; (ii) to discuss the methodological limitations of the studies so far conducted and delineate a theoretical framework on dopamine mechanisms of TRS; and (iii) to highlight future perspectives of research and unmet needs. Dopamine-related neurobiological mechanisms of TRS may be multiple and putatively subdivided into three biological points: (1) D2R-related, including increased D2R levels; increased density of D2Rs in the high-affinity state; aberrant D2R dimer or heteromer formation; imbalance between D2R short and long variants; extrastriatal D2Rs; (2) presynaptic dopamine, including low or normal dopamine synthesis and/or release compared to responder patients; and (3) exaggerated postsynaptic D2R-mediated neurotransmission. Future points to be addressed are: (i) a more neurobiologically-oriented phenotypic categorization of TRS; (ii) implementation of neurobiological studies by directly comparing treatment resistant vs. treatment responder patients; (iii) development of a reliable animal model of non-response to antipsychotics.
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Dhawan V, Niethammer MH, Lesser ML, Pappas KN, Hellman M, Fitzpatrick TM, Bjelke D, Singh J, Quatarolo LM, Choi YY, Oh A, Eidelberg D, Chaly T. Prospective F-18 FDOPA PET Imaging Study in Human PD. Nucl Med Mol Imaging 2022; 56:147-157. [DOI: 10.1007/s13139-022-00748-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2021] [Revised: 03/18/2022] [Accepted: 03/21/2022] [Indexed: 11/28/2022] Open
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3
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Kim S, Shin SH, Santangelo B, Veronese M, Kang SK, Lee JS, Cheon GJ, Lee W, Kwon JS, Howes OD, Kim E. Dopamine dysregulation in psychotic relapse after antipsychotic discontinuation: an [ 18F]DOPA and [ 11C]raclopride PET study in first-episode psychosis. Mol Psychiatry 2021; 26:3476-3488. [PMID: 32929214 DOI: 10.1038/s41380-020-00879-0] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/22/2020] [Revised: 08/24/2020] [Accepted: 09/03/2020] [Indexed: 01/09/2023]
Abstract
Although antipsychotic drugs are effective for relieving the psychotic symptoms of first-episode psychosis (FEP), psychotic relapse is common during the course of the illness. While some FEPs remain remitted even without medication, antipsychotic discontinuation is regarded as the most common risk factor for the relapse. Considering the actions of antipsychotic drugs on presynaptic and postsynaptic dopamine dysregulation, this study evaluated possible mechanisms underlying relapse after antipsychotic discontinuation. Twenty five FEPs who were clinically stable and 14 matched healthy controls were enrolled. Striatal dopamine activity was assessed as Kicer value using [18F]DOPA PET before and 6 weeks after antipsychotic discontinuation. The D2/3 receptor availability was measured as BPND using [11C]raclopride PET after antipsychotic discontinuation. Healthy controls also underwent PET scans according to the corresponding schedule of the patients. Patients were monitored for psychotic relapse during 12 weeks after antipsychotic discontinuation. 40% of the patients showed psychotic relapse after antipsychotic discontinuation. The change in Kicer value over time significantly differed between relapsed, non-relapsed patients and healthy controls (Week*Group: F = 4.827, df = 2,253.193, p = 0.009). In relapsed patients, a significant correlation was found between baseline striatal Kicer values and time to relapse after antipsychotic discontinuation (R2 = 0.518, p = 0.018). BPND were not significantly different between relapsed, non-relapsed patients and healthy controls (F = 1.402, df = 2,32.000, p = 0.261). These results suggest that dysfunctional dopamine autoregulation might precipitate psychotic relapse after antipsychotic discontinuation in FEP. This finding could be used for developing a strategy for the prevention of psychotic relapse related to antipsychotic discontinuation.
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Affiliation(s)
- Seoyoung Kim
- Department of Psychiatry, Seoul National University Bundang Hospital, Gyeonggi-do, Republic of Korea
| | - Sang Ho Shin
- Department of Psychiatry, Seoul National University Bundang Hospital, Gyeonggi-do, Republic of Korea
| | - Barbara Santangelo
- Centre for Neuroimaging Science, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK
| | - Mattia Veronese
- Centre for Neuroimaging Science, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK
| | - Seung Kwan Kang
- Department of Nuclear Medicine, College of Medicine, Seoul National University, Seoul, Republic of Korea.,Department of Biomedical Sciences, College of Medicine, Seoul National University, Seoul, Republic of Korea
| | - Jae Sung Lee
- Department of Nuclear Medicine, College of Medicine, Seoul National University, Seoul, Republic of Korea.,Department of Biomedical Sciences, College of Medicine, Seoul National University, Seoul, Republic of Korea
| | - Gi Jeong Cheon
- Department of Nuclear Medicine, College of Medicine, Seoul National University, Seoul, Republic of Korea.,Institute of Radiation Medicine, College of Medicine, Seoul National University, Seoul, Republic of Korea
| | - Woojoo Lee
- Department of Public Health Science, Graduate School of Public Health, Seoul National University, Seoul, Republic of Korea
| | - Jun Soo Kwon
- Department of Psychiatry, College of Medicine, Seoul National University, Seoul, Republic of Korea.,Department of Brain & Cognitive Sciences, College of Natural Sciences, Seoul National University, Seoul, Republic of Korea
| | - Oliver D Howes
- Department of Psychosis studies, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK.,Psychiatric Imaging, Medical Research Council Clinical Sciences Centre, Imperial College London, Hammersmith Hospital Campus, London, UK
| | - Euitae Kim
- Department of Psychiatry, Seoul National University Bundang Hospital, Gyeonggi-do, Republic of Korea. .,Department of Psychiatry, College of Medicine, Seoul National University, Seoul, Republic of Korea. .,Department of Brain & Cognitive Sciences, College of Natural Sciences, Seoul National University, Seoul, Republic of Korea.
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4
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Egerton A, Murphy A, Donocik J, Anton A, Barker GJ, Collier T, Deakin B, Drake R, Eliasson E, Emsley R, Gregory CJ, Griffiths K, Kapur S, Kassoumeri L, Knight L, Lambe EJB, Lawrie SM, Lees J, Lewis S, Lythgoe DJ, Matthews J, McGuire P, McNamee L, Semple S, Shaw AD, Singh KD, Stockton-Powdrell C, Talbot PS, Veronese M, Wagner E, Walters JTR, Williams SR, MacCabe JH, Howes OD. Dopamine and Glutamate in Antipsychotic-Responsive Compared With Antipsychotic-Nonresponsive Psychosis: A Multicenter Positron Emission Tomography and Magnetic Resonance Spectroscopy Study (STRATA). Schizophr Bull 2021; 47:505-516. [PMID: 32910150 PMCID: PMC7965076 DOI: 10.1093/schbul/sbaa128] [Citation(s) in RCA: 51] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The variability in the response to antipsychotic medication in schizophrenia may reflect between-patient differences in neurobiology. Recent cross-sectional neuroimaging studies suggest that a poorer therapeutic response is associated with relatively normal striatal dopamine synthesis capacity but elevated anterior cingulate cortex (ACC) glutamate levels. We sought to test whether these measures can differentiate patients with psychosis who are antipsychotic responsive from those who are antipsychotic nonresponsive in a multicenter cross-sectional study. 1H-magnetic resonance spectroscopy (1H-MRS) was used to measure glutamate levels (Glucorr) in the ACC and in the right striatum in 92 patients across 4 sites (48 responders [R] and 44 nonresponders [NR]). In 54 patients at 2 sites (25 R and 29 NR), we additionally acquired 3,4-dihydroxy-6-[18F]fluoro-l-phenylalanine (18F-DOPA) positron emission tomography (PET) to index striatal dopamine function (Kicer, min-1). The mean ACC Glucorr was higher in the NR than the R group after adjustment for age and sex (F1,80 = 4.27; P = .04). This was associated with an area under the curve for the group discrimination of 0.59. There were no group differences in striatal dopamine function or striatal Glucorr. The results provide partial further support for a role of ACC glutamate, but not striatal dopamine synthesis, in determining the nature of the response to antipsychotic medication. The low discriminative accuracy might be improved in groups with greater clinical separation or increased in future studies that focus on the antipsychotic response at an earlier stage of the disorder and integrate other candidate predictive biomarkers. Greater harmonization of multicenter PET and 1H-MRS may also improve sensitivity.
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Affiliation(s)
- Alice Egerton
- Department of Psychosis Studies, Institute of Psychiatry, Psychology & Neuroscience, King’s College London, London, UK
- NIHR Biomedical Research Centre at South London and Maudsley NHS Foundation Trust, London, UK
| | - Anna Murphy
- Division of Neuroscience and Experimental Psychology, School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, UK
| | - Jacek Donocik
- Department of Psychosis Studies, Institute of Psychiatry, Psychology & Neuroscience, King’s College London, London, UK
| | - Adriana Anton
- Division of Neuroscience and Experimental Psychology, School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, UK
- Academic Unit of Radiology, Medical School, Faculty of Medicine, Dentistry & Health, University of Sheffield, Sheffield, UK
| | - Gareth J Barker
- NIHR Biomedical Research Centre at South London and Maudsley NHS Foundation Trust, London, UK
- Department of Neuroimaging, Institute of Psychiatry, Psychology & Neuroscience, King’s College London, London, UK
| | - Tracy Collier
- Department of Psychosis Studies, Institute of Psychiatry, Psychology & Neuroscience, King’s College London, London, UK
- NIHR Biomedical Research Centre at South London and Maudsley NHS Foundation Trust, London, UK
| | - Bill Deakin
- Division of Neuroscience and Experimental Psychology, School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, UK
| | - Richard Drake
- Division of Psychology and Mental Health, School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, UK
| | - Emma Eliasson
- Division of Psychiatry, University of Edinburgh, Edinburgh, UK
| | - Richard Emsley
- NIHR Biomedical Research Centre at South London and Maudsley NHS Foundation Trust, London, UK
- Department of Biostatistics and Health Informatics, Institute of Psychiatry, Psychology & Neuroscience, King’s College London, London, UK
| | - Catherine J Gregory
- Division of Neuroscience and Experimental Psychology, School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, UK
| | - Kira Griffiths
- Department of Psychosis Studies, Institute of Psychiatry, Psychology & Neuroscience, King’s College London, London, UK
| | - Shitij Kapur
- Department of Psychosis Studies, Institute of Psychiatry, Psychology & Neuroscience, King’s College London, London, UK
- NIHR Biomedical Research Centre at South London and Maudsley NHS Foundation Trust, London, UK
- Faculty of Medicine, Dentistry and Health Sciences, University of Melbourne, Parkville, Victoria, Australia
| | - Laura Kassoumeri
- Department of Psychosis Studies, Institute of Psychiatry, Psychology & Neuroscience, King’s College London, London, UK
- NIHR Biomedical Research Centre at South London and Maudsley NHS Foundation Trust, London, UK
| | - Laura Knight
- CUBRIC, School of Psychology, College of Biomedical and Life Sciences, Cardiff University, Cardiff, UK
| | - Emily J B Lambe
- CUBRIC, School of Psychology, College of Biomedical and Life Sciences, Cardiff University, Cardiff, UK
| | | | - Jane Lees
- Division of Psychology and Mental Health, School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, UK
| | - Shôn Lewis
- Division of Psychology and Mental Health, School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, UK
| | - David J Lythgoe
- NIHR Biomedical Research Centre at South London and Maudsley NHS Foundation Trust, London, UK
- Department of Neuroimaging, Institute of Psychiatry, Psychology & Neuroscience, King’s College London, London, UK
| | - Julian Matthews
- Division of Neuroscience and Experimental Psychology, School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, UK
| | - Philip McGuire
- Department of Psychosis Studies, Institute of Psychiatry, Psychology & Neuroscience, King’s College London, London, UK
- NIHR Biomedical Research Centre at South London and Maudsley NHS Foundation Trust, London, UK
| | - Lily McNamee
- Division of Psychiatry, University of Edinburgh, Edinburgh, UK
| | - Scott Semple
- Centre for Cardiovascular Science, University of Edinburgh, Edinburgh, UK
| | - Alexander D Shaw
- CUBRIC, School of Psychology, College of Biomedical and Life Sciences, Cardiff University, Cardiff, UK
| | - Krish D Singh
- CUBRIC, School of Psychology, College of Biomedical and Life Sciences, Cardiff University, Cardiff, UK
| | - Charlotte Stockton-Powdrell
- Division of Psychology and Mental Health, School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, UK
| | - Peter S Talbot
- Division of Neuroscience and Experimental Psychology, School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, UK
| | - Mattia Veronese
- NIHR Biomedical Research Centre at South London and Maudsley NHS Foundation Trust, London, UK
- Department of Neuroimaging, Institute of Psychiatry, Psychology & Neuroscience, King’s College London, London, UK
| | - Ernest Wagner
- Division of Psychiatry, University of Edinburgh, Edinburgh, UK
| | - James T R Walters
- MRC Centre for Neuropsychiatric Genetics and Genomics, Division of Psychological Medicine and Clinical Neurosciences, School of Medicine, Cardiff University, Cardiff, UK
| | - Stephen R Williams
- Division of Informatics, Imaging and Data Sciences, University of Manchester, Manchester, UK
| | - James H MacCabe
- Department of Psychosis Studies, Institute of Psychiatry, Psychology & Neuroscience, King’s College London, London, UK
- NIHR Biomedical Research Centre at South London and Maudsley NHS Foundation Trust, London, UK
| | - Oliver D Howes
- Department of Psychosis Studies, Institute of Psychiatry, Psychology & Neuroscience, King’s College London, London, UK
- NIHR Biomedical Research Centre at South London and Maudsley NHS Foundation Trust, London, UK
- Psychiatric Imaging Group, MRC London Institute of Medical Sciences, Hammersmith Hospital, London, UK
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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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Harris KL, Kuan WL, Mason SL, Barker RA. Antidopaminergic treatment is associated with reduced chorea and irritability but impaired cognition in Huntington's disease (Enroll-HD). J Neurol Neurosurg Psychiatry 2020; 91:622-630. [PMID: 32229581 PMCID: PMC7279191 DOI: 10.1136/jnnp-2019-322038] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/10/2019] [Revised: 02/26/2020] [Accepted: 03/13/2020] [Indexed: 02/02/2023]
Abstract
OBJECTIVES Alterations in dopamine neurotransmission underlie some of the clinical features of Huntington's disease (HD) and as such are a target for therapeutic intervention, especially for the treatment of chorea and some behavioural problems. However, justification for such an intervention is mainly based on case reports and small open label studies and the effects these drugs have on cognition in HD remain unclear. METHODS In this study, we used the Enroll-HD observational database to assess the effects of antidopaminergic medication on motor, psychiatric and cognitive decline, over a 3-year period. We first looked at the annual rate of decline of a group of HD patients taking antidopaminergic medication (n=466) compared with an untreated matched group (n=466). The groups were matched on specified clinical variables using propensity score matching. Next, we studied a separate group of HD patients who were prescribed such medications part way through the study (n=90) and compared their rate of change before and after the drugs were introduced and compared this to a matched control group. RESULTS We found that HD patients taking antidopaminergic medication had a slower progression in chorea and irritability compared with those not taking such medications. However, this same group of patients also displayed significantly greater rate of decline in a range of cognitive tasks. CONCLUSION In conclusion we found that antidopaminergic treatment is associated with improvements in the choreic movements and irritability of HD but worsens cognition. However, further research is required to prospectively investigate this and whether these are causally linked, ideally in a double-blind placebo-controlled trial.
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Affiliation(s)
- Kate L Harris
- Department of Clinical Neurosciences, The University of Cambridge, Cambridge, United Kingdom
| | - Wei-Li Kuan
- Department of Clinical Neurosciences, The University of Cambridge, Cambridge, United Kingdom
| | - Sarah L Mason
- Department of Clinical Neurosciences, Cambridge Centre for Brain Repair, Cambridge, Cambridgeshire, United Kingdom
| | - Roger A Barker
- Department of Clinical Neurosciences, John van Geest Centre for Brain Repair, and MRC-WT Cambridge Stem Cell Institute, University of Cambridge, Cambridge, United Kingdom
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Taïeb D, Hicks RJ, Hindié E, Guillet BA, Avram A, Ghedini P, Timmers HJ, Scott AT, Elojeimy S, Rubello D, Virgolini IJ, Fanti S, Balogova S, Pandit-Taskar N, Pacak K. European Association of Nuclear Medicine Practice Guideline/Society of Nuclear Medicine and Molecular Imaging Procedure Standard 2019 for radionuclide imaging of phaeochromocytoma and paraganglioma. Eur J Nucl Med Mol Imaging 2019; 46:2112-2137. [PMID: 31254038 PMCID: PMC7446938 DOI: 10.1007/s00259-019-04398-1] [Citation(s) in RCA: 195] [Impact Index Per Article: 39.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2019] [Accepted: 06/10/2019] [Indexed: 01/11/2023]
Abstract
PURPOSE Diverse radionuclide imaging techniques are available for the diagnosis, staging, and follow-up of phaeochromocytoma and paraganglioma (PPGL). Beyond their ability to detect and localise the disease, these imaging approaches variably characterise these tumours at the cellular and molecular levels and can guide therapy. Here we present updated guidelines jointly approved by the EANM and SNMMI for assisting nuclear medicine practitioners in not only the selection and performance of currently available single-photon emission computed tomography and positron emission tomography procedures, but also the interpretation and reporting of the results. METHODS Guidelines from related fields and relevant literature have been considered in consultation with leading experts involved in the management of PPGL. The provided information should be applied according to local laws and regulations as well as the availability of various radiopharmaceuticals. CONCLUSION Since the European Association of Nuclear Medicine 2012 guidelines, the excellent results obtained with gallium-68 (68Ga)-labelled somatostatin analogues (SSAs) in recent years have simplified the imaging approach for PPGL patients that can also be used for selecting patients for peptide receptor radionuclide therapy as a potential alternative or complement to the traditional theranostic approach with iodine-123 (123I)/iodine-131 (131I)-labelled meta-iodobenzylguanidine. Genomic characterisation of subgroups with differing risk of lesion development and subsequent metastatic spread is refining the use of molecular imaging in the personalised approach to hereditary PPGL patients for detection, staging, and follow-up surveillance.
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Affiliation(s)
- David Taïeb
- Department of Nuclear Medicine, La Timone University Hospital, CERIMED, Aix-Marseille University, 264 rue Saint-Pierre, 13005, Marseille Cedex 05, France.
| | - Rodney J Hicks
- Centre for Cancer Imaging, Peter MacCallum Cancer Centre, Melbourne, VIC, Australia
| | - Elif Hindié
- Department of Nuclear Medicine, Hôpital Haut-Lévêque, Bordeaux University Hospitals, Pessac, France
| | - Benjamin A Guillet
- Department of Radiopharmacy, La Timone University Hospital, CERIMED, Aix-Marseille University, Marseille, France
| | - Anca Avram
- Nuclear Medicine/Radiology, University of Michigan, Ann Arbor, MI, USA
| | - Pietro Ghedini
- Nuclear Medicine Unit, Medicina Nucleare Metropolitana, University Hospital S.Orsola-Malpighi, Bologna, Italy
| | - Henri J Timmers
- Department of Endocrinology, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
| | | | - Saeed Elojeimy
- Department of Radiology, University of New Mexico, Albuquerque, NM, USA
| | - Domenico Rubello
- Department of Nuclear Medicine, Radiology, Neuroradiology, Medical Physics, Clinical Laboratory, Microbiology, Pathology, Transfusional Medicine, Santa Maria della Misericordia Hospital, Rovigo, Italy
| | - Irène J Virgolini
- Department of Nuclear Medicine, Medical University Innsbruck, Anichstrasse 35, 6020, Innsbruck, Austria
| | - Stefano Fanti
- Nuclear Medicine Unit, Medicina Nucleare Metropolitana, University Hospital S.Orsola-Malpighi, Bologna, Italy
| | - Sona Balogova
- Department of Nuclear Medicine, Comenius University and St. Elisabeth Oncology Institute, Heydukova 10, 81250, Bratislava, Slovakia
- Department of Nuclear Medicine, Hôpital Tenon Assistance Publique-Hôpitaux de Paris and Sorbonne University, Paris, France
| | - Neeta Pandit-Taskar
- Department of Radiology, Molecular Imaging and Therapy Service, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Karel Pacak
- Eunice Kennedy Shriver National Institutes of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA
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Affiliation(s)
- Gerhard Gründer
- Central Institute of Mental Health, Department of Molecular Neuroimaging, Medical Faculty Mannheim, University of Heidelberg, Mannheim, Germany
| | - Paul Cumming
- Institute for Nuclear Medicine, Inselspital, Berne University, Berne, Switzerland
- School of Psychology and Counselling and IHBI, Queensland University of Technology, Brisbane, Australia
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McCutcheon RA, Abi-Dargham A, Howes OD. Schizophrenia, Dopamine and the Striatum: From Biology to Symptoms. Trends Neurosci 2019; 42:205-220. [PMID: 30621912 PMCID: PMC6401206 DOI: 10.1016/j.tins.2018.12.004] [Citation(s) in RCA: 385] [Impact Index Per Article: 77.0] [Reference Citation Analysis] [Abstract] [Key Words] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2018] [Revised: 12/04/2018] [Accepted: 12/16/2018] [Indexed: 12/15/2022]
Abstract
The mesolimbic hypothesis has been a central dogma of schizophrenia for decades, positing that aberrant functioning of midbrain dopamine projections to limbic regions causes psychotic symptoms. Recently, however, advances in neuroimaging techniques have led to the unanticipated finding that dopaminergic dysfunction in schizophrenia is greatest within nigrostriatal pathways, implicating the dorsal striatum in the pathophysiology and calling into question the mesolimbic theory. At the same time our knowledge of striatal anatomy and function has progressed, suggesting new mechanisms via which striatal dysfunction may contribute to the symptoms of schizophrenia. This Review draws together these developments, to explore what they mean for our understanding of the pathophysiology, clinical manifestations, and treatment of the disorder. Techniques for characterising the mesostriatal dopamine system, both in humans and animal models, have advanced significantly over the past decade. In vivo imaging studies in schizophrenia patients demonstrate that dopaminergic dysfunction in schizophrenia is greatest in nigrostriatal as opposed to mesolimbic pathways. Better understanding of striatal structure and function has enhanced our insight into the neurobiological basis of psychotic symptoms. The role of other neurotransmitters in modulating striatal dopamine function merits further exploration, and modulating these neurotransmitter systems has potential to offer new therapeutic strategies.
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Affiliation(s)
- Robert A McCutcheon
- Department of Psychosis Studies, Institute of Psychiatry, Psychology & Neuroscience, King's College London, De Crespigny Park, London, SE5 8AF, UK; MRC London Institute of Medical Sciences, Hammersmith Hospital, London, W12 0NN, UK; Institute of Clinical Sciences, Faculty of Medicine, Imperial College London, London, W12 0NN, UK; South London and Maudsley NHS Foundation Trust, London, SE5 8AF, UK
| | - Anissa Abi-Dargham
- Department of Psychiatry, School of Medicine, Stony Brook University, New York, USA
| | - Oliver D Howes
- Department of Psychosis Studies, Institute of Psychiatry, Psychology & Neuroscience, King's College London, De Crespigny Park, London, SE5 8AF, UK; MRC London Institute of Medical Sciences, Hammersmith Hospital, London, W12 0NN, UK; Institute of Clinical Sciences, Faculty of Medicine, Imperial College London, London, W12 0NN, UK; South London and Maudsley NHS Foundation Trust, London, SE5 8AF, UK.
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10
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Amato D, Kruyer A, Samaha AN, Heinz A. Hypofunctional Dopamine Uptake and Antipsychotic Treatment-Resistant Schizophrenia. Front Psychiatry 2019; 10:314. [PMID: 31214054 PMCID: PMC6557273 DOI: 10.3389/fpsyt.2019.00314] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/30/2019] [Accepted: 04/23/2019] [Indexed: 01/07/2023] Open
Abstract
Antipsychotic treatment resistance in schizophrenia remains a major issue in psychiatry. Nearly 30% of patients with schizophrenia do not respond to antipsychotic treatment, yet the underlying neurobiological causes are unknown. All effective antipsychotic medications are thought to achieve their efficacy by targeting the dopaminergic system. Here we review early literature describing the fundamental mechanisms of antipsychotic drug efficacy, highlighting mechanistic concepts that have persisted over time. We then reconsider the original framework for understanding antipsychotic efficacy in light of recent advances in our scientific understanding of the dopaminergic effects of antipsychotics. Based on these new insights, we describe a role for the dopamine transporter in the genesis of both antipsychotic therapeutic response and primary resistance. We believe that this discussion will help delineate the dopaminergic nature of antipsychotic treatment-resistant schizophrenia.
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Affiliation(s)
- Davide Amato
- Department of Neuroscience, Medical University of South Carolina, Charleston, SC, United States
| | - Anna Kruyer
- Department of Neuroscience, Medical University of South Carolina, Charleston, SC, United States
| | - Anne-Noël Samaha
- Department of Pharmacology and Physiology, Faculty of Medicine, Université de Montréal, Montreal, QC, Canada
| | - Andreas Heinz
- Department of Psychiatry, Charité University Medicine Berlin, Campus Charité Mitte, Berlin, Germany
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Jauhar S, Veronese M, Nour MM, Rogdaki M, Hathway P, Turkheimer FE, Stone J, Egerton A, McGuire P, Kapur S, Howes OD. Determinants of treatment response in first-episode psychosis: an 18F-DOPA PET study. Mol Psychiatry 2019; 24:1502-1512. [PMID: 29679071 PMCID: PMC6331038 DOI: 10.1038/s41380-018-0042-4] [Citation(s) in RCA: 84] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/23/2017] [Revised: 12/04/2017] [Accepted: 01/15/2018] [Indexed: 11/10/2022]
Abstract
Psychotic illnesses show variable responses to treatment. Determining the neurobiology underlying this is important for precision medicine and the development of better treatments. It has been proposed that dopaminergic differences underlie variation in response, with striatal dopamine synthesis capacity (DSC) elevated in responders and unaltered in non-responders. We therefore aimed to test this in a prospective cohort, with a nested case-control comparison. 40 volunteers (26 patients with first-episode psychosis and 14 controls) received an 18F-DOPA Positron Emission Tomography scan to measure DSC (Kicer) prior to antipsychotic treatment. Clinical assessments (Positive and Negative Syndrome Scale, PANSS, and Global Assessment of Functioning, GAF) occurred at baseline and following antipsychotic treatment for a minimum of 4 weeks. Response was defined using improvement in PANSS Total score of >50%. Patients were followed up for at least 6 months, and remission criteria applied. There was a significant effect of group on Kicer in associative striatum (F(2, 37) = 7.9, p = 0.001). Kicer was significantly higher in responders compared with non-responders (Cohen's d = 1.55, p = 0.01) and controls (Cohen's d = 1.31, p = 0.02). Kicer showed significant positive correlations with improvements in PANSS-positive (r = 0.64, p < 0.01), PANSS negative (rho = 0.51, p = 0.01), and PANSS total (rho = 0.63, p < 0.01) ratings and a negative relationship with change in GAF (r = -0.55, p < 0.01). Clinical response is related to baseline striatal dopaminergic function. Differences in dopaminergic function between responders and non-responders are present at first episode of psychosis, consistent with dopaminergic and non-dopaminergic sub-types in psychosis, and potentially indicating a neurochemical basis to stratify psychosis.
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Affiliation(s)
- Sameer Jauhar
- 0000 0001 2322 6764grid.13097.3cDepartment of Psychosis Studies, Institute of Psychiatry, Psychology and Neuroscience, King’s College, London, UK ,0000 0000 9439 0839grid.37640.36Early Intervention Psychosis Clinical Academic Group, South London & Maudsley NHS Trust, London, UK
| | - Mattia Veronese
- 0000 0001 2322 6764grid.13097.3cCentre for Neuroimaging Sciences, Institute of Psychiatry, Psychology and Neuroscience, King’s College, London, UK
| | - Matthew M Nour
- 0000 0001 2322 6764grid.13097.3cDepartment of Psychosis Studies, Institute of Psychiatry, Psychology and Neuroscience, King’s College, London, UK ,0000 0001 0705 4923grid.413629.bPsychiatric Imaging Group MRC London Institute of Medical Sciences, Hammersmith Hospital, London, W12 0NN UK ,0000 0001 0705 4923grid.413629.bInstitute of Clinical Sciences, Faculty of Medicine, Imperial College, Hammersmith Hospital, London, W12 0NN UK
| | - Maria Rogdaki
- 0000 0001 2322 6764grid.13097.3cDepartment of Psychosis Studies, Institute of Psychiatry, Psychology and Neuroscience, King’s College, London, UK ,0000 0001 0705 4923grid.413629.bPsychiatric Imaging Group MRC London Institute of Medical Sciences, Hammersmith Hospital, London, W12 0NN UK
| | - Pamela Hathway
- 0000 0001 2322 6764grid.13097.3cDepartment of Psychosis Studies, Institute of Psychiatry, Psychology and Neuroscience, King’s College, London, UK
| | - Federico E. Turkheimer
- 0000 0001 2322 6764grid.13097.3cCentre for Neuroimaging Sciences, Institute of Psychiatry, Psychology and Neuroscience, King’s College, London, UK
| | - James Stone
- 0000 0001 2322 6764grid.13097.3cDepartment of Psychosis Studies, Institute of Psychiatry, Psychology and Neuroscience, King’s College, London, UK ,0000 0001 2322 6764grid.13097.3cCentre for Neuroimaging Sciences, Institute of Psychiatry, Psychology and Neuroscience, King’s College, London, UK
| | - Alice Egerton
- 0000 0001 2322 6764grid.13097.3cDepartment of Psychosis Studies, Institute of Psychiatry, Psychology and Neuroscience, King’s College, London, UK
| | - Philip McGuire
- 0000 0001 2322 6764grid.13097.3cDepartment of Psychosis Studies, Institute of Psychiatry, Psychology and Neuroscience, King’s College, London, UK ,0000 0000 9439 0839grid.37640.36Early Intervention Psychosis Clinical Academic Group, South London & Maudsley NHS Trust, London, UK
| | - Shitij Kapur
- 0000 0001 2322 6764grid.13097.3cFiona Pepper, Centre for Neuroimaging Sciences, King’s College, London, UK
| | - Oliver D Howes
- Department of Psychosis Studies, Institute of Psychiatry, Psychology and Neuroscience, King's College, London, UK. .,Psychiatric Imaging Group MRC London Institute of Medical Sciences, Hammersmith Hospital, London, W12 0NN, UK. .,Institute of Clinical Sciences, Faculty of Medicine, Imperial College, Hammersmith Hospital, London, W12 0NN, UK.
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12
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Kim JH, Cumming P, Son YD, Kim HK, Joo YH, Kim JH. Altered connectivity between striatal and extrastriatal regions in patients with schizophrenia on maintenance antipsychotics: an [18
F]fallypride PET and functional MRI study. Synapse 2018; 72:e22064. [DOI: 10.1002/syn.22064] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2018] [Revised: 07/25/2018] [Accepted: 07/26/2018] [Indexed: 01/20/2023]
Affiliation(s)
- Jeong-Hee Kim
- Research Institute for Advanced Industrial Technology; Korea University; Sejong Republic of Korea
- Neuroscience Research Institute; Gachon University; Incheon Republic of Korea
| | - Paul Cumming
- School of Psychology and Counselling and IHBI; Queensland University of Technology, and QIMR Berghofer Institute; Brisbane Queensland Australia
| | - Young-Don Son
- Neuroscience Research Institute; Gachon University; Incheon Republic of Korea
- Department of Biomedical Engineering; College of Health Science, Gachon University; Incheon Republic of Korea
| | - Hang-Keun Kim
- Neuroscience Research Institute; Gachon University; Incheon Republic of Korea
- Department of Biomedical Engineering; College of Health Science, Gachon University; Incheon Republic of Korea
| | - Yo-Han Joo
- Neuroscience Research Institute; Gachon University; Incheon Republic of Korea
| | - Jong-Hoon Kim
- Neuroscience Research Institute; Gachon University; Incheon Republic of Korea
- Department of Psychiatry, Gil Medical Center; Gachon University College of Medicine, Gachon University; Incheon Republic of Korea
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13
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Hengartner MP, Moncrieff J. Inconclusive Evidence in Support of the Dopamine Hypothesis of Psychosis: Why Neurobiological Research Must Consider Medication Use, Adjust for Important Confounders, Choose Stringent Comparators, and Use Larger Samples. Front Psychiatry 2018; 9:174. [PMID: 29765340 PMCID: PMC5938402 DOI: 10.3389/fpsyt.2018.00174] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/24/2018] [Accepted: 04/16/2018] [Indexed: 12/28/2022] Open
Affiliation(s)
- Michael P Hengartner
- Department of Applied Psychology, Zurich University of Applied Sciences, Zurich, Switzerland
| | - Joanna Moncrieff
- Division of Psychiatry, University College London, London, United Kingdom
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Liemburg EJ, van Es F, Knegtering H, Aleman A. Effects of aripiprazole versus risperidone on brain activation during planning and social-emotional evaluation in schizophrenia: A single-blind randomized exploratory study. Prog Neuropsychopharmacol Biol Psychiatry 2017; 79:112-119. [PMID: 28558941 DOI: 10.1016/j.pnpbp.2017.05.022] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/01/2017] [Revised: 04/28/2017] [Accepted: 05/26/2017] [Indexed: 12/28/2022]
Abstract
Impaired function of prefrontal brain networks may be the source of both negative symptoms and neurocognitive problems in psychotic disorders. Whereas most antipsychotics may decrease prefrontal activation, the partial dopamine D2-receptor agonist aripiprazole is hypothesized to improve prefrontal function. This study investigated whether patients with a psychotic disorder would show stronger activation of prefrontal areas and associated regions after treatment with aripiprazole compared to risperidone treatment. In this exploratory pharmacological neuroimaging study, 24 patients were randomly assigned to either aripiprazole or risperidone. At baseline and after nine weeks treatment they underwent an interview and MRI session. Here we report on brain activation (measured with arterial spin labeling) during performance of two tasks, the Tower of London and the Wall of Faces. Aripiprazole treatment decreased activation of the middle frontal, superior frontal and occipital gyrus (ToL) and medial temporal and inferior frontal gyrus, putamen and cuneus (WoF), while activation increased after risperidone. Activation increased in the ventral anterior cingulate and posterior insula (ToL), and superior frontal, superior temporal and precentral gyrus (WoF) after aripiprazole treatment and decreased after risperidone. Both treatment groups had increased ventral insula activation (ToL) and middle temporal gyrus (WoF), and decreased occipital cortex, precuneus and caudate head activation (ToL) activation. In conclusion, patients treated with aripiprazole may need less frontal resources for planning performance and may show increased frontotemporal and frontostriatal reactivity to emotional stimuli. More research is needed to corroborate and extend these preliminary findings.
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Affiliation(s)
- Edith J Liemburg
- BCN Neuroimaging Center, Department of Neuroscience, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands; Rob Giel Research Center, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands.
| | - Frank van Es
- Rob Giel Research Center, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands; University Center Psychiatry, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands.
| | - Henderikus Knegtering
- BCN Neuroimaging Center, Department of Neuroscience, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands; Rob Giel Research Center, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands; Lentis Research, Center for Mental Health, Groningen, The Netherlands.
| | - André Aleman
- BCN Neuroimaging Center, Department of Neuroscience, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands; Department of Psychology, University of Groningen, Groningen, The Netherlands.
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15
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Wolf A, Leucht S, Pajonk FG. Do antipsychotics lead to cognitive impairment in dementia? A meta-analysis of randomised placebo-controlled trials. Eur Arch Psychiatry Clin Neurosci 2017; 267:187-198. [PMID: 27530185 DOI: 10.1007/s00406-016-0723-4] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/17/2015] [Accepted: 08/07/2016] [Indexed: 01/01/2023]
Abstract
Behavioural and psychological symptoms in dementia (BPSD) are common and often treated with antipsychotics, which are known to have small efficacy and to cause many side effects. One potential side effect might be cognitive decline. We searched MEDLINE, Scopus, CENTRAL and www.ClincalStudyResult.org for randomized, double-blind, placebo-controlled trials using antipsychotics for treating BPSD and evaluated cognitive functioning. The studies identified were summarized in a meta-analysis with the standardized mean difference (SMD, Hedges's g) as the effect size. Meta-regression was additionally performed to identify associated factors. Ten studies provided data on the course of cognitive functioning. The random effects model of the pooled analysis showed a not significant effect (SMD = -0.065, 95 % CI -0.186 to 0.057, I 2 = 41 %). Meta-regression revealed a significant correlation between cognitive impairment and treatment duration (R 2 = 0.78, p < 0.02) as well as baseline MMSE (R 2 = 0.92, p < 0.005). These correlations depend on only two out of ten studies and should interpret cautiously.
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Affiliation(s)
- Alexander Wolf
- Department of Anaesthesiology, Intensive Care and Pain Medicine, Saarland University Medical Center, Homburg, Germany
| | - Stefan Leucht
- Department of Psychiatry and Psychotherapy, Klinikum rechts der Isar der Technischen Universität München, Ismaninger Str. 22, 81675, Munich, Germany
| | - Frank-Gerald Pajonk
- Department of Psychiatry and Psychotherapy, Klinikum rechts der Isar der Technischen Universität München, Ismaninger Str. 22, 81675, Munich, Germany.
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16
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Kim E, Howes OD, Veronese M, Beck K, Seo S, Park JW, Lee JS, Lee YS, Kwon JS. Presynaptic Dopamine Capacity in Patients with Treatment-Resistant Schizophrenia Taking Clozapine: An [ 18F]DOPA PET Study. Neuropsychopharmacology 2017; 42:941-950. [PMID: 27857125 PMCID: PMC5312074 DOI: 10.1038/npp.2016.258] [Citation(s) in RCA: 86] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/18/2016] [Revised: 11/09/2016] [Accepted: 11/11/2016] [Indexed: 01/20/2023]
Abstract
Some patients with schizophrenia show poor response to first-line antipsychotic treatments and this is termed treatment-resistant schizophrenia. The differential response to first-line antipsychotic drugs may reflect a different underlying neurobiology. Indeed, a previous study found dopamine synthesis capacity was significantly lower in patients with treatment-resistant schizophrenia. However, in this study, the treatment-resistant patients were highly symptomatic, whereas the responsive patients showed no or minimal symptoms. The study could not distinguish whether this was a trait effect or reflected the difference in symptom levels. Thus, we aimed to test whether dopaminergic function is altered in patients with a history of treatment resistance to first-line drugs relative to treatment responders when both groups are matched for symptom severity levels by recruiting treatment-resistant patients currently showed low symptom severity with the clozapine treatment. Healthy controls (n=12), patients treated with clozapine (n=12) who had not responded to first-line antipsychotics, and patients who had responded to first-line antipsychotics (n=12) were recruited. Participants were matched for age and sex and symptomatic severity level in patient groups. Participants' dopamine synthesis capacity was measured by using [18F]DOPA PET. We found that patients treated with clozapine show lower dopamine synthesis capacity than patients who have responded to first-line treatment (Cohen's d=0.9191 (whole striatum), 0.7781 (associative striatum), 1.0344 (limbic striatum), and 1.0189 (sensorimotor striatum) in line with the hypothesis that the dopaminergic function is linked to treatment response. This suggests that a different neurobiology may underlie treatment-resistant schizophrenia and that dopamine synthesis capacity may be a useful biomarker to predict treatment responsiveness.
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Affiliation(s)
- Euitae Kim
- Department of Neuropsychiatry, Seoul National University Bundang Hospital, Gyeonggi-do, Korea
| | - Oliver D Howes
- Psychiatric Imaging, Medical Research Council Clinical Sciences Centre, Imperial College London, Hammersmith Hospital Campus, London, UK,Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK
| | - Mattia Veronese
- Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK
| | - Katherine Beck
- Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK
| | - Seongho Seo
- Department of Brain & Cognitive Sciences, College of Natural Sciences, Seoul National University, Seoul, Korea,Department of Nuclear Medicine, Seoul National University College of Medicine, Seoul, Korea
| | - Jin Woo Park
- Department of Psychiatry, Seoul National University College of Medicine, Seoul, Korea
| | - Jae Sung Lee
- Department of Brain & Cognitive Sciences, College of Natural Sciences, Seoul National University, Seoul, Korea,Department of Nuclear Medicine, Seoul National University College of Medicine, Seoul, Korea
| | - Yun-Sang Lee
- Department of Nuclear Medicine, Seoul National University College of Medicine, Seoul, Korea
| | - Jun Soo Kwon
- Department of Brain & Cognitive Sciences, College of Natural Sciences, Seoul National University, Seoul, Korea,Department of Psychiatry, Seoul National University College of Medicine, Seoul, Korea,Department of Psychiatry, Seoul National University College of Medicine and Department of Brain and Cognitive Sciences, College of Natural Sciences, Seoul National University, 28 Yeongon-dong, Chongno-gu, Seoul 110-744, Korea, Tel: +82 2 2072 2972, Fax: +82 2 747 9063, E-mail:
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17
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Short-term Effects of Risperidone Monotherapy on Spontaneous Brain Activity in First-episode Treatment-naïve Schizophrenia Patients: A Longitudinal fMRI Study. Sci Rep 2016; 6:34287. [PMID: 27698361 PMCID: PMC5048418 DOI: 10.1038/srep34287] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2016] [Accepted: 09/09/2016] [Indexed: 01/25/2023] Open
Abstract
It is unclear whether abnormal spontaneous neural activation patterns found in chronic schizophrenia patients (CSP) are part of the pathogenesis of disease, consequences of chronic illness, or effects of antipsychotic treatment. We performed a longitudinal resting-state functional magnetic resonance imaging (fMRI) study in 42 treatment-naïve first-episode schizophrenia patients (FESP) at baseline and then after 8-weeks of risperidone monotherapy, and compared the findings to 38 healthy volunteers. Spontaneous brain activity was quantified using the fractional amplitude of low-frequency fluctuations (fALFF) and regional homogeneity (ReHo) and compared between patients and controls. Pretreatment, patients exhibited higher fALFF in left caudate compared with controls. After treatment, patients had elevated fALFF in bilateral putamen and right caudate, and increased ReHo in right caudate and left putamen. Greater increase of fALFF in the left putamen correlated with less improvement in positive symptoms. Thus, abnormalities of spontaneous neural activity in chronic schizophrenia is at least partly due to a medication effect. The observed post-treatment increase in striatal intrinsic activity may reflect counter-therapeutic functional adaptation to dopamine D2 receptor occupancy required for medication effects on psychosis.
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18
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Rademacher L, Prinz S, Winz O, Henkel K, Dietrich CA, Schmaljohann J, Mohammadkhani Shali S, Schabram I, Stoppe C, Cumming P, Hilgers RD, Kumakura Y, Coburn M, Mottaghy FM, Gründer G, Vernaleken I. Effects of Smoking Cessation on Presynaptic Dopamine Function of Addicted Male Smokers. Biol Psychiatry 2016; 80:198-206. [PMID: 26803340 DOI: 10.1016/j.biopsych.2015.11.009] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/05/2015] [Revised: 10/25/2015] [Accepted: 11/11/2015] [Indexed: 10/22/2022]
Abstract
BACKGROUND There is evidence of abnormal cerebral dopamine transmission in nicotine-dependent smokers, but it is unclear whether dopaminergic abnormalities are due to acute nicotine abuse or whether they persist with abstinence. We addressed this question by conducting longitudinal positron emission tomography (PET) examination of smokers before and after 3 months of abstinence. METHODS We obtained baseline 6-[(18)F]fluoro-L-DOPA (FDOPA)-PET scans in 15 nonsmokers and 30 nicotine-dependent smokers, who either smoked as per their usual habit or were in acute withdrawal. All smokers then underwent cessation treatment, and successful abstainers were re-examined by FDOPA-PET after 3 months of abstinence (n = 15). Uptake of FDOPA was analyzed using a steady-state model yielding estimates of the dopamine synthesis capacity (K); the turnover of tracer dopamine formed in living brain (kloss); and the tracer distribution volume (Vd), which is an index of dopamine storage capacity. RESULTS Compared with nonsmokers, K was 15% to 20% lower in the caudate nuclei of consuming smokers. Intraindividual comparisons of consumption and long-term abstinence revealed significant increases in K in the right dorsal and left ventral caudate nuclei. Relative to acute withdrawal, Vd significantly decreased in the right ventral and dorsal caudate after prolonged abstinence. Severity of nicotine dependence significantly correlated with dopamine synthesis capacity and dopamine turnover in the bilateral ventral putamen of consuming smokers. CONCLUSIONS The results suggest a lower dopamine synthesis capacity in nicotine-dependent smokers that appears to normalize with abstinence. Further investigations are needed to clarify the role of dopamine in nicotine addiction to help develop smoking prevention and cessation treatments.
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Affiliation(s)
- Lena Rademacher
- Department of Psychiatry, Psychotherapy and Psychosomatics, RWTH Aachen University, Aachen; Department of Psychiatry and Psychotherapy, Social Neuroscience Laboratory, University of Lübeck, Lübeck, Germany.
| | - Susanne Prinz
- Department of Psychiatry, Psychotherapy and Psychosomatics, RWTH Aachen University, Aachen; Department of Psychiatry and Psychotherapy, Centre for Integrative Psychiatry, University of Zürich, Rheinau, Switzerland
| | - Oliver Winz
- Department of Nuclear Medicine, RWTH Aachen University, Aachen
| | - Karsten Henkel
- Department of Psychiatry, Psychotherapy and Psychosomatics, RWTH Aachen University, Aachen
| | - Claudia A Dietrich
- Department of Psychiatry, Psychotherapy and Psychosomatics, RWTH Aachen University, Aachen
| | | | | | - Ina Schabram
- Department of Psychiatry, Psychotherapy and Psychosomatics, RWTH Aachen University, Aachen
| | - Christian Stoppe
- Department of Anesthesiology, RWTH Aachen University, Aachen; Institute of Biochemistry and Molecular Cell Biology, RWTH Aachen University, Aachen
| | - Paul Cumming
- Department of Neuropsychiatry and Psychosomatic Medicine, Oslo University Hospital, Oslo, Norway; School of Psychology and Counselling, Queensland University of Technology, Brisbane, Queensland, Australia
| | | | - Yoshitaka Kumakura
- Department of Pharmacology and Neuroscience, University of Copenhagen, Copenhagen, Denmark
| | - Mark Coburn
- Department of Anesthesiology, RWTH Aachen University, Aachen
| | - Felix M Mottaghy
- Department of Nuclear Medicine, RWTH Aachen University, Aachen; Jülich/Aachen Research Alliance, Aachen, Germany; Department of Nuclear Medicine, Maastricht University Medical Center, Maastricht, The Netherlands
| | - Gerhard Gründer
- Department of Psychiatry, Psychotherapy and Psychosomatics, RWTH Aachen University, Aachen; Jülich/Aachen Research Alliance, Aachen, Germany
| | - Ingo Vernaleken
- Department of Psychiatry, Psychotherapy and Psychosomatics, RWTH Aachen University, Aachen; Jülich/Aachen Research Alliance, Aachen, Germany
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19
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Pan B, Chen J, Lian J, Huang XF, Deng C. Unique Effects of Acute Aripiprazole Treatment on the Dopamine D2 Receptor Downstream cAMP-PKA and Akt-GSK3β Signalling Pathways in Rats. PLoS One 2015; 10:e0132722. [PMID: 26162083 PMCID: PMC4498891 DOI: 10.1371/journal.pone.0132722] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2015] [Accepted: 06/17/2015] [Indexed: 01/01/2023] Open
Abstract
Aripiprazole is a wide-used antipsychotic drug with therapeutic effects on both positive and negative symptoms of schizophrenia, and reduced side-effects. Although aripiprazole was developed as a dopamine D2 receptor (D2R) partial agonist, all other D2R partial agonists that aimed to mimic aripiprazole failed to exert therapeutic effects in clinic. The present in vivo study aimed to investigate the effects of aripiprazole on the D2R downstream cAMP-PKA and Akt-GSK3β signalling pathways in comparison with a D2R antagonist – haloperidol and a D2R partial agonist – bifeprunox. Rats were injected once with aripiprazole (0.75mg/kg, i.p.), bifeprunox (0.8mg/kg, i.p.), haloperidol (0.1mg/kg, i.p.) or vehicle. Five brain regions – the prefrontal cortex (PFC), nucleus accumbens (NAc), caudate putamen (CPu), ventral tegmental area (VTA) and substantia nigra (SN) were collected. The protein levels of PKA, Akt and GSK3β were measured by Western Blotting; the cAMP levels were examined by ELISA tests. The results showed that aripiprazole presented similar acute effects on PKA expression to haloperidol, but not bifeprunox, in the CPU and VTA. Additionally, aripiprazole was able to increase the phosphorylation of GSK3β in the PFC, NAc, CPu and SN, respectively, which cannot be achieved by bifeprunox and haloperidol. These results suggested that acute treatment of aripiprazole had differential effects on the cAMP-PKA and Akt-GSK3β signalling pathways from haloperidol and bifeprunox in these brain areas. This study further indicated that, by comparison with bifeprunox, the unique pharmacological profile of aripiprazole may be attributed to the relatively lower intrinsic activity at D2R.
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Affiliation(s)
- Bo Pan
- Antipsychotic Research Laboratory, Illawarra Health and Medical Research Institute, Wollongong, NSW, Australia
- Centre for Translational Neuroscience, School of Medicine, University of Wollongong, Wollongong, NSW, Australia
| | - Jiezhong Chen
- Antipsychotic Research Laboratory, Illawarra Health and Medical Research Institute, Wollongong, NSW, Australia
| | - Jiamei Lian
- Antipsychotic Research Laboratory, Illawarra Health and Medical Research Institute, Wollongong, NSW, Australia
- Centre for Translational Neuroscience, School of Medicine, University of Wollongong, Wollongong, NSW, Australia
| | - Xu-Feng Huang
- Centre for Translational Neuroscience, School of Medicine, University of Wollongong, Wollongong, NSW, Australia
| | - Chao Deng
- Antipsychotic Research Laboratory, Illawarra Health and Medical Research Institute, Wollongong, NSW, Australia
- Centre for Translational Neuroscience, School of Medicine, University of Wollongong, Wollongong, NSW, Australia
- * E-mail:
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20
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Bolstad I, Andreassen OA, Groote IR, Haatveit B, Server A, Jensen J. No difference in frontal cortical activity during an executive functioning task after acute doses of aripiprazole and haloperidol. Front Hum Neurosci 2015; 9:296. [PMID: 26074803 PMCID: PMC4443021 DOI: 10.3389/fnhum.2015.00296] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2015] [Accepted: 05/09/2015] [Indexed: 11/16/2022] Open
Abstract
Background: Aripiprazole is an atypical antipsychotic drug that is characterized by partial dopamine D2 receptor agonism. Its pharmacodynamic profile is proposed to be beneficial in the treatment of cognitive impairment, which is prevalent in psychotic disorders. This study compared brain activation characteristics produced by aripiprazole with that of haloperidol, a typical D2 receptor antagonist, during a task targeting executive functioning. Methods: Healthy participants received an acute oral dose of haloperidol, aripiprazole or placebo before performing an executive functioning task while blood-oxygen-level-dependent (BOLD) functional magnetic resonance imaging (fMRI) was carried out. Results: There was a tendency towards reduced performance in the aripiprazole group compared to the two other groups. The image analysis yielded a strong task-related BOLD-fMRI response within each group. An uncorrected between-group analysis showed that aripiprazole challenge resulted in stronger activation in the frontal and temporal gyri and the putamen compared with haloperidol challenge, but after correcting for multiple testing there was no significant group difference. Conclusion: No significant group differences between aripiprazole and haloperidol in frontal cortical activation were obtained when corrected for multiple comparisons. This study is registered in ClinicalTrials.gov (identifier: 2009-016222-14).1
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Affiliation(s)
- Ingeborg Bolstad
- NORMENT, KG Jebsen Centre for Psychosis Research, Division of Mental Health and Addiction, Oslo University Hospital Oslo, Norway ; Institute of Clinical Medicine, University of Oslo Oslo, Norway
| | - Ole A Andreassen
- NORMENT, KG Jebsen Centre for Psychosis Research, Division of Mental Health and Addiction, Oslo University Hospital Oslo, Norway ; Institute of Clinical Medicine, University of Oslo Oslo, Norway
| | - Inge R Groote
- Department of Psychology, Institute of Social Sciences, University of Oslo Oslo, Norway
| | - Beathe Haatveit
- NORMENT, KG Jebsen Centre for Psychosis Research, Division of Mental Health and Addiction, Oslo University Hospital Oslo, Norway ; Institute of Clinical Medicine, University of Oslo Oslo, Norway
| | - Andres Server
- Department of Neuroradiology, Oslo University Hospital Oslo, Norway
| | - Jimmy Jensen
- NORMENT, KG Jebsen Centre for Psychosis Research, Division of Mental Health and Addiction, Oslo University Hospital Oslo, Norway ; Centre for Psychology, Kristianstad University Kristianstad, Sweden
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Acute and sustained effects of methylphenidate on cognition and presynaptic dopamine metabolism: an [18F]FDOPA PET study. J Neurosci 2015; 34:14769-76. [PMID: 25355228 DOI: 10.1523/jneurosci.1560-14.2014] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Methylphenidate (MPH) inhibits the reuptake of dopamine and noradrenaline. PET studies with MPH challenge show increased competition at postsynaptic D2/3-receptors, thus indirectly revealing presynaptic dopamine release. We used [(18)F]fluorodopamine ([(18)F]FDOPA)-PET in conjunction with the inlet-outlet model (IOM) of Kumakura et al. (2007) to investigate acute and long-term changes in dopamine synthesis capacity and turnover in nigrostriatal fibers of healthy subjects with MPH challenge. Twenty healthy human females underwent two dynamic [(18)F]FDOPA PET scans (124 min; slow bolus-injection; arterial blood sampling), with one scan in untreated baseline condition and the other after MPH administration (0.5 mg/kg, p.o.), in randomized order. Subjects underwent cognitive testing at each PET session. Time activity curves were obtained for ventral putamen and caudate and were analyzed according to the IOM to obtain the regional net-uptake of [(18)F]FDOPA (K; dopamine synthesis capacity) as well as the [(18)F]fluorodopamine washout rate (kloss, index of dopamine turnover). MPH substantially decreased kloss in putamen (-22%; p = 0.003). In the reversed treatment order group (MPH/no drug), K was increased by 18% at no drug follow-up. The magnitude of K at the no drug baseline correlated with cognitive parameters. Furthermore, individual kloss changes correlated with altered cognitive performance under MPH. [(18)F]FDOPA PET in combination with the IOM detects an MPH-evoked decrease in striatal dopamine turnover, in accordance with the known acute pharmacodynamics of MPH. Furthermore, the scan-ordering effect on K suggested that a single MPH challenge persistently increased striatal dopamine synthesis capacity. Attenuation of dopamine turnover by MPH is linked to enhanced cognitive performance in healthy females.
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Piel M, Vernaleken I, Rösch F. Positron Emission Tomography in CNS Drug Discovery and Drug Monitoring. J Med Chem 2014; 57:9232-58. [DOI: 10.1021/jm5001858] [Citation(s) in RCA: 111] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Affiliation(s)
- Markus Piel
- Institute
of Nuclear Chemistry, Johannes Gutenberg-University, Fritz-Strassmann-Weg 2, D-55128 Mainz, Germany
| | - Ingo Vernaleken
- Department
of Psychiatry, Psychotherapy, and Psychosomatics, RWTH Aachen University, Pauwelsstraße 30, D-52074 Aachen, Germany
| | - Frank Rösch
- Institute
of Nuclear Chemistry, Johannes Gutenberg-University, Fritz-Strassmann-Weg 2, D-55128 Mainz, Germany
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Fatouros-Bergman H, Cervenka S, Flyckt L, Edman G, Farde L. Meta-analysis of cognitive performance in drug-naïve patients with schizophrenia. Schizophr Res 2014; 158:156-62. [PMID: 25086658 DOI: 10.1016/j.schres.2014.06.034] [Citation(s) in RCA: 169] [Impact Index Per Article: 16.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/05/2013] [Revised: 06/18/2014] [Accepted: 06/18/2014] [Indexed: 12/27/2022]
Abstract
Cognitive deficits represent a significant characteristic of schizophrenia. However, a majority of the clinical studies have been conducted in antipsychotic drug treated patients. Thus, it remains unclear if significant cognitive impairments exist in the absence of medication. This is the first meta-analysis of cognitive findings in drug-naïve patients with schizophrenia. Cognitive data from 23 studies encompassing 1106 patients and 1385 controls published from 1992 to 2013 were included. Tests were to a large extent ordered in cognitive domains according to the Measurement and Treatment Research to Improve Cognition in Schizophrenia (MATRICS) battery. Analysis was performed with STATA using the random-effects model and heterogeneity as well as Egger's publication bias was assessed. Overall the results show that patients performed worse than healthy controls in all cognitive domains with medium to large effect sizes. Verbal memory, speed of processing and working memory were three of the domains with the greatest impairments. The pattern of results is in line with previous meta-analytic findings in antipsychotic treated patients. The present meta-analysis confirms the existence of significant cognitive impairments at the early stage of the illness in the absence of antipsychotic medication.
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Affiliation(s)
- Helena Fatouros-Bergman
- Karolinska Institutet, Dept. of Clinical Neurosciences, Centre for Psychiatric Research, Patientvägen 2, 112 19 Stockholm, Sweden.
| | - Simon Cervenka
- Karolinska Institutet, Dept. of Clinical Neurosciences, Centre for Psychiatric Research, R5, Karolinska University Hospital, 171 76 Stockholm, Sweden.
| | - Lena Flyckt
- Karolinska Institutet, Dept. of Clinical Neurosciences, Centre for Psychiatric Research, Patientvägen 2, 112 19 Stockholm, Sweden.
| | - Gunnar Edman
- Department of Psychiatry, Tiohundra AB, SE-761 30 Norrtälje, Sweden; Karolinska Institutet, Department of Neurobiology, Care Sciences and Society, Centre of Family Medicine - CeFAM, S-141 83 Huddinge, Sweden.
| | - Lars Farde
- Karolinska Institutet, Dept. of Clinical Neurosciences, Centre for Psychiatric Research, R5, Karolinska University Hospital, 171 76 Stockholm, Sweden.
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24
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Bonoldi I, Howes OD. Presynaptic dopaminergic function: implications for understanding treatment response in psychosis. CNS Drugs 2014; 28:649-63. [PMID: 24919790 DOI: 10.1007/s40263-014-0177-z] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
All current antipsychotic drugs block dopamine (DA) receptors, but the nature of the DA dysfunction in schizophrenia has not been clear. However, consistent evidence now shows that presynaptic dopaminergic function is altered in schizophrenia, specifically in terms of increased DA synthesis capacity, baseline synaptic DA levels, and DA release. Furthermore, presynaptic dopaminergic function is already elevated in prodromal patients who later developed the disorder. Currently available antipsychotics act on postsynaptic receptors, not targeting presynaptic DA abnormalities. This has implications for understanding response and developing new treatments. The lack of normalization of the abnormal presynaptic function could explain why discontinuation is likely to lead to relapse, because the major dopaminergic function persists, meaning that once treatment stops there is nothing to oppose the dysregulated dopamine function reinstating symptoms. Furthermore, it suggests that drugs that target presynaptic dopaminergic function may constitute new treatment possibilities for schizophrenic patients, in particular, for those in whom antipsychotics are poorly effective. In addition, the longitudinal changes with the onset of psychosis indicate the potential to target a defined dynamic neurochemical abnormality to prevent the onset of psychosis.
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Affiliation(s)
- I Bonoldi
- Department of Psychosis Studies, Institute of Psychiatry, King's College of London, De Crespigny Park 16, London, SE5 8AF, UK,
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25
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Kim E, Howes OD, Kapur S. Molecular imaging as a guide for the treatment of central nervous system disorders. DIALOGUES IN CLINICAL NEUROSCIENCE 2014. [PMID: 24174903 PMCID: PMC3811103 DOI: 10.31887/dcns.2013.15.3/ekim] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Molecular imaging techniques have a number of advantages for research into the pathophysiology and treatment of central nervous system (CNS) disorders. Firstly, they provide a noninvasive means of characterizing physiological processes in the living brain, enabling molecular alterations to be linked to clinical changes. Secondly, the pathophysiological target in a given CNS disorder can be measured in animal models and in experimental human models in the same way, which enables translational research. Moreover, as molecular imaging facilitates the detection of functional change which precedes gross pathology, it is particularly useful for the early diagnosis and treatment of CNS disorders. This review considers the application of molecular imaging to CNS disorders focusing on its potential to inform the development and evaluation of treatments. We focus on schizophrenia, Parkinson's disease, depression, and dementia as major CNS disorders. We also review the potential of molecular imaging to guide new drug development for CNS disorders.
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Affiliation(s)
- Euitae Kim
- Department of Neuropsychiatry, Seoul National University Bundang Hospital, Gyeonggi-do 463-707, Korea
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26
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Conway CR, Chibnall JT, Cumming P, Mintun MA, Gebara MAI, Perantie DC, Price JL, Cornell ME, McConathy JE, Gangwani S, Sheline YI. Antidepressant response to aripiprazole augmentation associated with enhanced FDOPA utilization in striatum: a preliminary PET study. Psychiatry Res 2014; 221:231-9. [PMID: 24468015 PMCID: PMC3982608 DOI: 10.1016/j.pscychresns.2014.01.003] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/13/2013] [Revised: 01/03/2014] [Accepted: 01/07/2014] [Indexed: 01/28/2023]
Abstract
Several double blind, prospective trials have demonstrated an antidepressant augmentation efficacy of aripiprazole in depressed patients unresponsive to standard antidepressant therapy. Although aripiprazole is now widely used for this indication, and much is known about its receptor-binding properties, the mechanism of its antidepressant augmentation remains ill-defined. In vivo animal studies and in vitro human studies using cloned dopamine dopamine D2 receptors suggest aripiprazole is a partial dopamine agonist; in this preliminary neuroimaging trial, we hypothesized that aripiprazole's antidepressant augmentation efficacy arises from dopamine partial agonist activity. To test this, we assessed the effects of aripiprazole augmentation on the cerebral utilization of 6-[(18)F]-fluoro-3,4-dihydroxy-l-phenylalanine (FDOPA) using positron emission tomography (PET). Fourteen depressed patients, who had failed 8 weeks of antidepressant therapy with selective serotonin reuptake inhibitors, underwent FDOPA PET scans before and after aripiprazole augmentation; 11 responded to augmentation. Whole brain, voxel-wise comparisons of pre- and post-aripiprazole scans revealed increased FDOPA trapping in the right medial caudate of augmentation responders. An exploratory analysis of depressive symptoms revealed that responders experienced large improvements only in putatively dopaminergic symptoms of lassitude and inability to feel. These preliminary findings suggest that augmentation of antidepressant response by aripiprazole may be associated with potentiation of dopaminergic activity.
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Affiliation(s)
- Charles R. Conway
- Washington University School of Medicine, Department of Psychiatry, 660 South Euclid, Campus Box 8134, St. Louis, MO 63110, USA,Saint Louis University School of Medicine, Department of Neurology & Psychiatry, 1438 South Grand Boulevard, St. Louis, MO 63104, USA,Corresponding author contact information: Address: Washington University Department of Psychiatry, 660 South Euclid, Campus Box 8134, St. Louis, MO 63110, Phone: 314-362-0038; Fax: 314-362-7017,
| | - John T. Chibnall
- Saint Louis University School of Medicine, Department of Neurology & Psychiatry, 1438 South Grand Boulevard, St. Louis, MO 63104, USA
| | - Paul Cumming
- Department of Nuclear Medicine, Friedrich-Alexander University, Erlangen/Nuremberg, Germany
| | - Mark A. Mintun
- Washington University School of Medicine, Departments of Radiology and Psychiatry, St. Louis, MO 63110, USA and Avid Radiopharmaceuticals, Philadelphia, PA 19104, USA
| | - Marie Anne I. Gebara
- Washington University School of Medicine, Department of Psychiatry, 660 South Euclid, Campus Box 8134, St. Louis, MO 63110, USA
| | - Dana C. Perantie
- Washington University School of Medicine, Department of Psychiatry, 660 South Euclid, Campus Box 8134, St. Louis, MO 63110, USA
| | - Joseph L. Price
- Washington University School of Medicine, Department of Anatomy and Neurobiology, St. Louis, MO 63110, USA
| | - Martha E. Cornell
- Washington University School of Medicine, Department of Psychiatry, 660 South Euclid, Campus Box 8134, St. Louis, MO 63110, USA
| | - Jonathan E. McConathy
- Washington University School of Medicine, Department of Radiology, Division of Nuclear Medicine, St. Louis, MO 63110, USA
| | - Sunil Gangwani
- Washington University School of Medicine, Department of Psychiatry, 660 South Euclid, Campus Box 8134, St. Louis, MO 63110, USA
| | - Yvette I. Sheline
- Washington University School of Medicine, Departments of Psychiatry, Neurology, and Radiology, St. Louis, MO 63110, USA
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Deserno L, Boehme R, Heinz A, Schlagenhauf F. Reinforcement learning and dopamine in schizophrenia: dimensions of symptoms or specific features of a disease group? Front Psychiatry 2013; 4:172. [PMID: 24391603 PMCID: PMC3870301 DOI: 10.3389/fpsyt.2013.00172] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/10/2013] [Accepted: 12/07/2013] [Indexed: 01/26/2023] Open
Abstract
Abnormalities in reinforcement learning are a key finding in schizophrenia and have been proposed to be linked to elevated levels of dopamine neurotransmission. Behavioral deficits in reinforcement learning and their neural correlates may contribute to the formation of clinical characteristics of schizophrenia. The ability to form predictions about future outcomes is fundamental for environmental interactions and depends on neuronal teaching signals, like reward prediction errors. While aberrant prediction errors, that encode non-salient events as surprising, have been proposed to contribute to the formation of positive symptoms, a failure to build neural representations of decision values may result in negative symptoms. Here, we review behavioral and neuroimaging research in schizophrenia and focus on studies that implemented reinforcement learning models. In addition, we discuss studies that combined reinforcement learning with measures of dopamine. Thereby, we suggest how reinforcement learning abnormalities in schizophrenia may contribute to the formation of psychotic symptoms and may interact with cognitive deficits. These ideas point toward an interplay of more rigid versus flexible control over reinforcement learning. Pronounced deficits in the flexible or model-based domain may allow for a detailed characterization of well-established cognitive deficits in schizophrenia patients based on computational models of learning. Finally, we propose a framework based on the potentially crucial contribution of dopamine to dysfunctional reinforcement learning on the level of neural networks. Future research may strongly benefit from computational modeling but also requires further methodological improvement for clinical group studies. These research tools may help to improve our understanding of disease-specific mechanisms and may help to identify clinically relevant subgroups of the heterogeneous entity schizophrenia.
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Affiliation(s)
- Lorenz Deserno
- Max Planck Institute for Human Cognitive and Brain Sciences , Leipzig , Germany ; Department of Psychiatry and Psychotherapy, Charité - Universitätsmedizin Berlin , Berlin , Germany
| | - Rebecca Boehme
- Department of Psychiatry and Psychotherapy, Charité - Universitätsmedizin Berlin , Berlin , Germany
| | - Andreas Heinz
- Department of Psychiatry and Psychotherapy, Charité - Universitätsmedizin Berlin , Berlin , Germany
| | - Florian Schlagenhauf
- Max Planck Institute for Human Cognitive and Brain Sciences , Leipzig , Germany ; Department of Psychiatry and Psychotherapy, Charité - Universitätsmedizin Berlin , Berlin , Germany
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28
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Abstract
Cerebral dopamine (DA) transmission is thought to be an important modulator for the development and occurrence of aggressive behavior. However, the link between aggression and DA transmission in humans has not been investigated using molecular imaging and standardized behavioral tasks. We investigated aggression as a function of DA transmission in a group of (N = 21) healthy male volunteers undergoing 6-[18F]-fluoro-L-DOPA (FDOPA)-positron emission tomography (PET) and a modified version of the Point Subtraction Aggression Paradigm (PSAP). This task measures aggressive behavior during a monetary reward-related paradigm, where a putative adversary habitually tries to cheat. The participant can react in three ways (i.e., money substraction of the putative opponent [aggressive punishment], pressing a defense button, or continuing his money-making behavior). FDOPA-PET was analyzed using a steady-state model yielding estimates of the DA-synthesis capacity (K), the turnover of tracer DA formed in living brain (kloss), and the tracer distribution volume (Vd), which is an index of DA storage capacity. Significant negative correlations between PSAP aggressive responses and the DA-synthesis capacity were present in several regions, most prominently in the midbrain (r = -0.640; p = 0.002). Lower degrees of aggressive responses were associated with higher DA storage capacity in the striatum and midbrain. Additionally, there was a significant positive correlation between the investment into monetary incentive responses on the PSAP and DA-synthesis capacity, notably in the midbrain (r = +0.618, p = 0.003). The results suggest that individuals with low DA transmission capacity are more vulnerable to reactive/impulsive aggression in response to provocation.
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29
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Kumakura Y, Gjedde A, Caprioli D, Kienast T, Beck A, Plotkin M, Schlagenhauf F, Vernaleken I, Gründer G, Bartenstein P, Heinz A, Cumming P. Increased turnover of dopamine in caudate nucleus of detoxified alcoholic patients. PLoS One 2013; 8:e73903. [PMID: 24040111 PMCID: PMC3770672 DOI: 10.1371/journal.pone.0073903] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2013] [Accepted: 07/25/2013] [Indexed: 12/02/2022] Open
Abstract
A previous study of the DOPA decarboxylase substrate 6-[18F]fluoro-L-DOPA (FDOPA) with positron emission tomography (PET) detected no difference of the net blood-brain transfer rate (Kinapp) between detoxified alcoholic patients and healthy controls. Instead, the study revealed an inverse correlation between Kinapp in left ventral striatum and alcohol craving scores. To resolve the influx and efflux phases of radiolabeled molecules, we independently estimated the unidirectional blood-brain FDOPA clearance rate (K) and the washout rate of [18F]fluorodopamine and its deaminated metabolites (kloss), and we also calculated the total distribution volume of decarboxylated metabolites and unmetabolized FDOPA as a steady-state index of the dopamine storage capacity (Vd) in brain. The craving scores in the 12 alcoholics correlated positively with the rate of loss (kloss) in the left ventral striatum. We conclude that craving is most pronounced in the individuals with relatively rapid dopamine turnover in the left ventral striatum. The blood-brain clearance rate (K), corrected for subsequent loss of radiolabeled molecules from brain, was completely normal throughout the brain of the alcoholics, in whom the volume of distribution (Vd) was found to be significantly lower in the left caudate nucleus. The magnitude of Vd in the left caudate head was reduced by 43% relative to the 16 controls, consistent with a 58% increase of kloss. We interpret the findings as indicating that a trait for rapid dopamine turnover in the ventral striatum subserves craving and reward-dependence, leading to an acquired state of increased dopamine turnover in the dorsal striatum of detoxified alcoholic patients.
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Affiliation(s)
- Yoshitaka Kumakura
- Department of Neuroscience and Pharmacology, University of Copenhagen, Copenhagen, Denmark
- Center for Functionally Integrative Neuroscience, Aarhus University, Aarhus C, Denmark
- Department of Nuclear Medicine, Tokyo University, Tokyo, Japan
- * E-mail:
| | - Albert Gjedde
- Department of Neuroscience and Pharmacology, University of Copenhagen, Copenhagen, Denmark
- Center for Functionally Integrative Neuroscience, Aarhus University, Aarhus C, Denmark
| | - Daniele Caprioli
- Department of Experimental Psychology, Cambridge University, Cambridge, United Kingdom
| | - Thorsten Kienast
- Department of Psychiatry, Charité - Universitätsmedizin Berlin, Berlin, Germany
| | - Anne Beck
- Department of Psychiatry, Charité - Universitätsmedizin Berlin, Berlin, Germany
| | - Michail Plotkin
- Department of Nuclear Medicine, Charite - Universitätsmedizin Berlin, Berlin, Germany
| | | | - Ingo Vernaleken
- Department of Psychiatry, University of Aachen, Aachen, Germany
| | - Gerhard Gründer
- Department of Psychiatry, University of Aachen, Aachen, Germany
| | - Peter Bartenstein
- Department of Nuclear Medicine, Ludwig Maximilian University of Munich, Munich, Germany
| | - Andreas Heinz
- Department of Psychiatry, Charité - Universitätsmedizin Berlin, Berlin, Germany
| | - Paul Cumming
- Department of Nuclear Medicine, Ludwig Maximilian University of Munich, Munich, Germany
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30
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Egerton A, Chaddock CA, Winton-Brown TT, Bloomfield MAP, Bhattacharyya S, Allen P, McGuire PK, Howes OD. Presynaptic striatal dopamine dysfunction in people at ultra-high risk for psychosis: findings in a second cohort. Biol Psychiatry 2013; 74:106-12. [PMID: 23312565 DOI: 10.1016/j.biopsych.2012.11.017] [Citation(s) in RCA: 161] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/24/2012] [Revised: 11/13/2012] [Accepted: 11/15/2012] [Indexed: 11/15/2022]
Abstract
BACKGROUND Using positron emission tomography (PET), we previously observed increases in 3,4-dihydroxy-6-[(18)F]fluoro-L-phenylalanine ((18)F-DOPA) uptake in the striatum of subjects at ultra-high risk (UHR) for psychosis, indicating elevated presynaptic dopamine synthesis capacity. The purpose of this study was to test if this finding would be replicated in a second UHR cohort. METHODS (18)F-DOPA PET was used to estimate dopamine synthesis capacity in the striatum of an entirely new cohort of 26 individuals at UHR for psychosis (14 males, mean±SD age = 22.7±4.7 years) and 20 healthy volunteers matched for age and gender (11 males, mean±SD age = 24.5±4.5 years). RESULTS Dopamine synthesis capacity was elevated in the whole [t(44) = 2.6; p = .01, effect size = .81] and associative striatum [t(44) = 2.6; p = .01, effect size = .73] of UHR compared with control subjects. When the two samples were combined to give a final sample of 32 control and 50 UHR subjects, the higher levels of dopamine synthesis capacity in the UHR group reached significance across the whole [F(1,81) = 11.0; p = .001], associative [F(1,81) = 12.7; p = .001], and sensorimotor [F(1,81) = 4.7; p = .03], but not the limbic [F(1,81) = 2.1; p = .2], striatum. CONCLUSIONS The findings indicate that elevated dopamine synthesis capacity in the dorsal striatum is a robust feature of individuals at UHR for psychosis and provide further evidence that dopaminergic abnormalities precede the onset of psychosis.
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Affiliation(s)
- Alice Egerton
- Department of Psychosis Studies, Institute of Psychiatry, King's College London, London, United Kingdom.
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31
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Veselinovic T, Schorn H, Vernaleken IB, Hiemke C, Zernig G, Gur R, Gründer G. Effects of antipsychotic treatment on cognition in healthy subjects. J Psychopharmacol 2013; 27:374-85. [PMID: 23118022 DOI: 10.1177/0269881112466183] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Cognitive impairments can be observed in the majority of diseases with disturbed dopamine transmission. They are considered as core symptoms of schizophrenia, a disorder in which they appear to be particularly pronounced. Their neurobiological background is not yet sufficiently investigated, but dopaminergic systems are believed to play a crucial role. The aim of this single-blind, randomised, placebo-controlled study was to examine the effects of subchronic antidopaminergic treatment on cognitive functions in healthy subjects. In total, 72 healthy volunteers, randomised into four groups, received one antidopaminergic substance (aripiprazole, haloperidol or reserpine) or placebo, respectively, for 7 days. A comprehensive neurocognitive assessment was conducted at baseline, 24 h after the last medication intake and 7 days later. In the Digit Symbol Substitution Test a distinct, statistically significant improvement was measured in the second session in the placebo but not in the medication group. A significant group*time interaction for reaction times in three subtests of the Test battery for Attentional Performance (TAP) was also found. Our findings indicate that modulation of dopaminergic systems affects primarily speed of information processing, attention and learning. Absence of effects on other functions, differing from previous reports, may be an expression of a sufficient counter-regulation.
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Affiliation(s)
- Tanja Veselinovic
- Department of Psychiatry, Psychotherapy and Psychosomatics, Medical Faculty, RWTH Aachen University, Aachen, Germany.
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32
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Fusar-Poli P, Meyer-Lindenberg A. Striatal presynaptic dopamine in schizophrenia, part II: meta-analysis of [(18)F/(11)C]-DOPA PET studies. Schizophr Bull 2013; 39:33-42. [PMID: 22282454 PMCID: PMC3523905 DOI: 10.1093/schbul/sbr180] [Citation(s) in RCA: 169] [Impact Index Per Article: 15.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 11/08/2011] [Indexed: 11/13/2022]
Abstract
BACKGROUND Alterations in striatal dopamine neurotransmission are central to the emergence of psychotic symptoms and to the mechanism of action of antipsychotics. Although the functional integrity of the presynaptic system can be assessed by measuring striatal dopamine synthesis capacity (DSC), no quantitative meta-analysis is available. METHODS Eleven striatal (caudate and putamen) [(11)C/(18)F]-DOPA positron emission tomography studies comparing 113 patients with schizophrenia and 131 healthy controls were included in a quantitative meta-analysis of DSC. Demographic, clinical, and methodological variables were extracted from each study or obtained from the authors and tested as covariates. Hedges' g was used as a measure of effect size in Comprehensive Meta-Analysis. Publication bias was assessed with funnel plots and Egger's intercept. Heterogeneity was addressed with the Q statistic and I(2) index. RESULTS Patients and controls were well matched in sociodemographic variables (P > .05). Quantitative evaluation of publication bias was nonsignificant (P = .276). Heterogeneity across study was modest in magnitude and statistically nonsignificant (Q = 19.19; P = .078; I (2) = 39.17). Patients with schizophrenia showed increased striatal DSC as compared with controls (Hedges' g = 0.867, CI 95% from 0.594 to 1.140, Z = 6.222, P < .001). The DSC schizophrenia/control ratio showed a relatively homogenous elevation of around 14% in schizophrenic patients as compared with controls. DSC elevation was regionally confirmed in both caudate and putamen. Controlling for potential confounders such as age, illness duration, gender, psychotic symptoms, and exposure to antipsychotics had no impact on the results. Sensitivity analysis confirmed robustness of meta-analytic findings. CONCLUSIONS The present meta-analysis showed consistently increased striatal DSC in schizophrenia, with a 14% elevation in patients as compared with healthy controls.
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Affiliation(s)
- Paolo Fusar-Poli
- Section of Psychiatry,DepartmentofHealth Sciences, University of Pavia, Pavia, Italy.
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33
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Ito H, Takano H, Arakawa R, Takahashi H, Kodaka F, Takahata K, Nogami T, Suzuki M, Suhara T. Effects of dopamine D2 receptor partial agonist antipsychotic aripiprazole on dopamine synthesis in human brain measured by PET with L-[β-11C]DOPA. PLoS One 2012; 7:e46488. [PMID: 23029533 PMCID: PMC3460902 DOI: 10.1371/journal.pone.0046488] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2012] [Accepted: 09/05/2012] [Indexed: 12/15/2022] Open
Abstract
Dopamine D2 receptor partial agonist antipsychotic drugs can modulate dopaminergic neurotransmission as functional agonists or functional antagonists. The effects of antipsychotics on presynaptic dopaminergic functions, such as dopamine synthesis capacity, might also be related to their therapeutic efficacy. Positron emission tomography (PET) was used to examine the effects of the partial agonist antipsychotic drug aripiprazole on presynaptic dopamine synthesis in relation to dopamine D2 receptor occupancy and the resulting changes in dopamine synthesis capacity in healthy men. On separate days, PET studies with [11C]raclopride and L-[β-11C]DOPA were performed under resting condition and with single doses of aripiprazole given orally. Occupancy of dopamine D2 receptors corresponded to the doses of aripiprazole, but the changes in dopamine synthesis capacity were not significant, nor was the relation between dopamine D2 receptor occupancy and these changes. A significant negative correlation was observed between baseline dopamine synthesis capacity and changes in dopamine synthesis capacity by aripiprazole, indicating that this antipsychotic appears to stabilize dopamine synthesis capacity. The therapeutic effects of aripiprazole in schizophrenia might be related to such stabilizing effects on dopaminergic neurotransmission responsivity.
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Affiliation(s)
- Hiroshi Ito
- Molecular Imaging Center, National Institute of Radiological Sciences, Chiba, Japan.
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34
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Taïeb D, Timmers HJ, Hindié E, Guillet BA, Neumann HP, Walz MK, Opocher G, de Herder WW, Boedeker CC, de Krijger RR, Chiti A, Al-Nahhas A, Pacak K, Rubello D. EANM 2012 guidelines for radionuclide imaging of phaeochromocytoma and paraganglioma. Eur J Nucl Med Mol Imaging 2012; 39:1977-95. [PMID: 22926712 DOI: 10.1007/s00259-012-2215-8] [Citation(s) in RCA: 156] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2012] [Accepted: 07/31/2012] [Indexed: 10/27/2022]
Abstract
PURPOSE Radionuclide imaging of phaeochromocytomas (PCCs) and paragangliomas (PGLs) involves various functional imaging techniques and approaches for accurate diagnosis, staging and tumour characterization. The purpose of the present guidelines is to assist nuclear medicine practitioners in performing, interpreting and reporting the results of the currently available SPECT and PET imaging approaches. These guidelines are intended to present information specifically adapted to European practice. METHODS Guidelines from related fields, issued by the European Association of Nuclear Medicine and the Society of Nuclear Medicine, were taken into consideration and are partially integrated within this text. The same was applied to the relevant literature, and the final result was discussed with leading experts involved in the management of patients with PCC/PGL. The information provided should be viewed in the context of local conditions, laws and regulations. CONCLUSION Although several radionuclide imaging modalities are considered herein, considerable focus is given to PET imaging which offers high sensitivity targeted molecular imaging approaches.
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Affiliation(s)
- David Taïeb
- Department of Nuclear Medicine, La Timone University Hospital, CERIMED, Aix-Marseille University, France.
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Schlagenhauf F, Rapp MA, Huys QJM, Beck A, Wüstenberg T, Deserno L, Buchholz HG, Kalbitzer J, Buchert R, Bauer M, Kienast T, Cumming P, Plotkin M, Kumakura Y, Grace AA, Dolan RJ, Heinz A. Ventral striatal prediction error signaling is associated with dopamine synthesis capacity and fluid intelligence. Hum Brain Mapp 2012; 34:1490-9. [PMID: 22344813 DOI: 10.1002/hbm.22000] [Citation(s) in RCA: 82] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2011] [Revised: 10/11/2011] [Accepted: 11/08/2011] [Indexed: 11/10/2022] Open
Abstract
Fluid intelligence represents the capacity for flexible problem solving and rapid behavioral adaptation. Rewards drive flexible behavioral adaptation, in part via a teaching signal expressed as reward prediction errors in the ventral striatum, which has been associated with phasic dopamine release in animal studies. We examined a sample of 28 healthy male adults using multimodal imaging and biological parametric mapping with (1) functional magnetic resonance imaging during a reversal learning task and (2) in a subsample of 17 subjects also with positron emission tomography using 6-[(18) F]fluoro-L-DOPA to assess dopamine synthesis capacity. Fluid intelligence was measured using a battery of nine standard neuropsychological tests. Ventral striatal BOLD correlates of reward prediction errors were positively correlated with fluid intelligence and, in the right ventral striatum, also inversely correlated with dopamine synthesis capacity (FDOPA K inapp). When exploring aspects of fluid intelligence, we observed that prediction error signaling correlates with complex attention and reasoning. These findings indicate that individual differences in the capacity for flexible problem solving relate to ventral striatal activation during reward-related learning, which in turn proved to be inversely associated with ventral striatal dopamine synthesis capacity.
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Affiliation(s)
- Florian Schlagenhauf
- Department of Psychiatry and Psychotherapy, Campus Charité Mitte, Charité-Universitätsmedizin Berlin, Germany
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Effects of antipsychotic treatment on psychopathology and motor symptoms. A placebo-controlled study in healthy volunteers. Psychopharmacology (Berl) 2011; 218:733-48. [PMID: 21643673 DOI: 10.1007/s00213-011-2368-3] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/11/2011] [Accepted: 05/21/2011] [Indexed: 10/18/2022]
Abstract
RATIONALE There is increased interest in elucidating the range of symptoms of schizophrenia and their response to treatment with medications. Particularly negative and cognitive symptoms are often resistant to the therapy with currently available antipsychotics. There are even similarities between negative symptoms in psychosis and the side effects of antidopaminergic antipsychotic drugs. OBJECTIVES The aim of this randomized, single-blinded, placebo-controlled study was to investigate the influence of a subchronic, prolonged neuroleptic-induced dopamine deficit on psychopathology and subjective well-being in healthy subjects. METHODS Seventy-two healthy volunteers without history of psychiatric diseases were included. A 7-day antidopaminergic intervention was provided with aripiprazole, haloperidol, and reserpine. For the clinical assessment, structured interviews and psychopathology and extrapyramidal symptom scales were used. RESULTS Seven out of 18 participants (38.9%) randomized to the haloperidol group terminated the study ahead of schedule. In the reserpine and the haloperidol group, significantly higher levels of negative and positive symptoms (PANSS scale) were documented. Depressive symptoms predominantly occurred in the reserpine group. Among all participants experiencing the antidopaminergic intervention, the subgroup with positive family history among first and second-generation relatives developed more pronounced depressive symptoms. Concerning extrapyramidal motor symptoms, the haloperidol group had significantly more severe manifestations than all three other groups. CONCLUSION Antidopaminergic modulation in healthy subjects induced substantial impairments in several domains of subjective well-being. In particular an association between hypodopaminergic states and depressive symptoms was observed which may be amplified by a genetic predisposition.
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Kumakura Y, Cumming P. PET studies of cerebral levodopa metabolism: a review of clinical findings and modeling approaches. Neuroscientist 2010; 15:635-50. [PMID: 19793723 DOI: 10.1177/1073858409338217] [Citation(s) in RCA: 97] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
[(18)F]Fluoro-3,4-dihydroxyphenyl-L-alanine (FDOPA) was one of the first successful tracers for molecular imaging by positron emission tomography (PET), and has proven immensely valuable for studies of Parkinson's disease. Following intravenous FDOPA injection, the decarboxylated metabolite [(18)F] fluorodopamine is formed and trapped within terminals of the nigrostriatal dopamine neurons; reduction in the simple ratio between striatum and cerebellum is indicative of nigrostriatal degeneration. However, the kinetic analysis of dynamic FDOPA-PET recordings is formidably complex due to the entry into brain of the plasma metabolite O-methyl-FDOPA and due to the eventual washout of decarboxylated metabolites. Linear graphical analysis relative to a reference tissue input function is popular and convenient for routine clinical studies in which serial arterial blood samples are unavailable. This simplified approach has facilitated longitudinal studies in large patient cohorts. Linear graphical analysis relative to the metabolite-corrected arterial FDOPA input yields a more physiological index of FDOPA utilization, the net blood-brain clearance. Using a constrained compartmental model, FDOPA-PET recordings can be used to calculate the relative activity of the enzyme DOPA decarboxylase in living brain. We have extended this approach so as to obtain an index of steady-state trapping of [( 18)F]fluorodopamine in synaptic vesicles. Although simple methods of image analysis are sufficient for the purposes of routine clinical studies, the more complex approaches have revealed hidden aspects of brain dopamine in personality, healthy aging, and in the pathophysiologies of Parkinson's disease and schizophrenia.
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Affiliation(s)
- Yoshitaka Kumakura
- Department of Nuclear Medicine, Graduate School of Medicine, University of Tokyo, and Research Center for Advanced Science and Technology, the University of Tokyo, Tokyo, Japan.
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Egerton A, Demjaha A, McGuire P, Mehta MA, Howes OD. The test-retest reliability of 18F-DOPA PET in assessing striatal and extrastriatal presynaptic dopaminergic function. Neuroimage 2009; 50:524-531. [PMID: 20034580 DOI: 10.1016/j.neuroimage.2009.12.058] [Citation(s) in RCA: 113] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2009] [Revised: 12/08/2009] [Accepted: 12/12/2009] [Indexed: 11/17/2022] Open
Abstract
Brain presynaptic dopaminergic function can be assessed using 18F-DOPA positron emission tomography (PET). Regional 18F-DOPA utilization may be used to index dopaminergic abnormalities over time or dopaminergic response to treatment in clinical populations. Such studies require prior knowledge of the stability of the 18F-DOPA signal in the brain regions of interest. Test-retest reliability was examined in eight healthy volunteers who each received two 18F-DOPA PET scans, approximately 2 years apart. 18F-DOPA utilization (k(i)(cer)) was determined using graphical analysis relative to a reference tissue input (Patlak and Blasberg, 1985). Reproducibility (measured as the within-subjects variation) and reliability (measured as intraclass correlation coefficients, ICCs) of 18F-DOPA k(i)(cer) were assessed in the structural and functional subdivisions of the striatum and select extrastriatal brain regions. Voxel-based median ICC maps were used to visualize the distribution of 18F-DOPA k(i)(cer) reliability across the brain. The caudate and putamen, and associative and sensorimotor, striatal subdivisions showed good reliability across the two scan sessions with bilateral ICCs ranging from 0.681 to 0.944. Reliability was generally lower in extrastriatal regions, with bilateral ICCs ranging from 0.235 in the amygdala to 0.894 in the thalamus. These data confirm the utility of 18F-DOPA PET in assessing dopaminergic function in the striatum and select extrastriatal areas but highlight the limitations in using this approach to measure dopaminergic function in low uptake extrastriatal brain areas. This information can be used to optimize the experimental design of future studies investigating changes in brain dopaminergic function with 18F-DOPA.
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Affiliation(s)
- Alice Egerton
- Psychiatric Imaging, Medical Research Council Clinical Sciences Centre, Imperial College London, Hammersmith Hospital, Du Cane Road, London W12 0NN, United Kingdom.,Division of Neurosciences & Mental Health, Imperial College London, United Kingdom.,Department of Psychological Medicine, Institute of Psychiatry, King's College London, London SE5 8AF, United Kingdom
| | - Arsime Demjaha
- Psychiatric Imaging, Medical Research Council Clinical Sciences Centre, Imperial College London, Hammersmith Hospital, Du Cane Road, London W12 0NN, United Kingdom.,Department of Psychological Medicine, Institute of Psychiatry, King's College London, London SE5 8AF, United Kingdom
| | - Philip McGuire
- Department of Psychological Medicine, Institute of Psychiatry, King's College London, London SE5 8AF, United Kingdom
| | - Mitul A Mehta
- Psychiatric Imaging, Medical Research Council Clinical Sciences Centre, Imperial College London, Hammersmith Hospital, Du Cane Road, London W12 0NN, United Kingdom.,Division of Neurosciences & Mental Health, Imperial College London, United Kingdom.,Department of Psychological Medicine, Institute of Psychiatry, King's College London, London SE5 8AF, United Kingdom
| | - Oliver D Howes
- Psychiatric Imaging, Medical Research Council Clinical Sciences Centre, Imperial College London, Hammersmith Hospital, Du Cane Road, London W12 0NN, United Kingdom.,Division of Neurosciences & Mental Health, Imperial College London, United Kingdom.,Department of Psychological Medicine, Institute of Psychiatry, King's College London, London SE5 8AF, United Kingdom
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Effects of the antipsychotic risperidone on dopamine synthesis in human brain measured by positron emission tomography with L-[beta-11C]DOPA: a stabilizing effect for dopaminergic neurotransmission? J Neurosci 2009; 29:13730-4. [PMID: 19864585 DOI: 10.1523/jneurosci.4172-09.2009] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Effects of antipsychotic drugs have widely been considered to be mediated by blockade of postsynaptic dopamine D(2) receptors. Effects of antipsychotics on presynaptic functions of dopaminergic neurotransmission might also be related to therapeutic effects of antipsychotics. To investigate the effects of antipsychotics on presynaptic functions of dopaminergic neurotransmission in relation with occupancy of dopamine D(2) receptors, changes in dopamine synthesis capacity by antipsychotics and occupancy of dopamine D(2) receptors were measured by positron emission tomography (PET) in healthy men. PET studies using [(11)C]raclopride and L-[beta-(11)C]DOPA were performed under resting condition and oral administration of single dose of the antipsychotic drug risperidone on separate days. Although occupancy of dopamine D(2) receptors corresponding dose of risperidone was observed, the changes in dopamine synthesis capacity by the administration of risperidone were not significant, nor was the relation between the occupancy of dopamine D(2) receptors and these changes. A significant negative correlation was observed between the baseline dopamine synthesis capacity and the changes in dopamine synthesis capacity by risperidone, indicating that this antipsychotic can be assumed to stabilize the dopamine synthesis capacity. The therapeutic effects of risperidone in schizophrenia might be related to such stabilizing effects on dopaminergic neurotransmission responsivity.
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Elevated [(18)F]FDOPA utilization in the periaqueductal gray and medial nucleus accumbens of patients with early Parkinson's disease. Neuroimage 2009; 49:2933-9. [PMID: 19941962 DOI: 10.1016/j.neuroimage.2009.11.035] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2009] [Revised: 11/12/2009] [Accepted: 11/13/2009] [Indexed: 11/20/2022] Open
Abstract
PET studies with the DOPA decarboxylase substrate 6-[(18)F]fluoro-l-DOPA (FDOPA) reveal the storage of [(18)F]-fluorodopamine within synaptic vesicles, mainly of dopamine fibres. As such, FDOPA PET is a sensitive indicator of the integrity of the nigrostriatal dopamine innervation. Nonetheless, there have been several reports of focal elevations of FDOPA utilization in brain of patients with Parkinson's disease (PD), all based on reference tissue methods. To investigate this phenomenon further, we used voxel-wise steady-state kinetic analysis to search for regions of elevated FDOPA utilization (K; ml g(-1) min(-1)) and steady-state trapping (V(d); ml g(-1)) in a group of well-characterized patients with early, asymmetric PD, who were contrasted with an age-matched control group. Subtraction of the population mean parametric maps revealed foci of increased FDOPA utilization K (+25%) in the bilateral medial nucleus accumbens, whereas the expected declines in the trapping of FDOPA were seen in the caudate and putamen. This observation suggests hyperfunction of catecholamine fibres innervating specifically the limbic striatum, which could guide the design of future prospective FDOPA-PET studies of the impulse control disorders occurring in some PD patients under treatment with dopamine agonists. A focus of increased FDOPA influx and also V(d) was detected in the periaqueductal grey, consistent with some earlier reports based on reference tissue analysis. Increased FDOPA trapping in the periaqueductal grey of PD patients seems consistent with recent reports of increased activity of serotonin neurons in a rat model of parkinsonism.
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Multimodal functional imaging investigation before and after the onset of psychosis. Int J Neuropsychopharmacol 2009; 12:579-81. [PMID: 18925982 DOI: 10.1017/s146114570800953x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
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Abstract
The dopamine hypothesis of schizophrenia has been one of the most enduring ideas in psychiatry. Initially, the emphasis was on a role of hyperdopaminergia in the etiology of schizophrenia (version I), but it was subsequently reconceptualized to specify subcortical hyperdopaminergia with prefrontal hypodopaminergia (version II). However, these hypotheses focused too narrowly on dopamine itself, conflated psychosis and schizophrenia, and predated advances in the genetics, molecular biology, and imaging research in schizophrenia. Since version II, there have been over 6700 articles about dopamine and schizophrenia. We selectively review these data to provide an overview of the 5 critical streams of new evidence: neurochemical imaging studies, genetic evidence, findings on environmental risk factors, research into the extended phenotype, and animal studies. We synthesize this evidence into a new dopamine hypothesis of schizophrenia-version III: the final common pathway. This hypothesis seeks to be comprehensive in providing a framework that links risk factors, including pregnancy and obstetric complications, stress and trauma, drug use, and genes, to increased presynaptic striatal dopaminergic function. It explains how a complex array of pathological, positron emission tomography, magnetic resonance imaging, and other findings, such as frontotemporal structural and functional abnormalities and cognitive impairments, may converge neurochemically to cause psychosis through aberrant salience and lead to a diagnosis of schizophrenia. The hypothesis has one major implication for treatment approaches. Current treatments are acting downstream of the critical neurotransmitter abnormality. Future drug development and research into etiopathogenesis should focus on identifying and manipulating the upstream factors that converge on the dopaminergic funnel point.
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Affiliation(s)
- Oliver D. Howes
- Positron Emission Tomography (PET) Psychiatry Group, Medical Research Council (MRC) Clinical Sciences Centre, Faculty of Medicine, Imperial College London, Hammersmith Hospital Campus, London W12 0NN, UK,Institute of Psychiatry, King's College London, London SE5 8AF, UK
| | - Shitij Kapur
- Positron Emission Tomography (PET) Psychiatry Group, Medical Research Council (MRC) Clinical Sciences Centre, Faculty of Medicine, Imperial College London, Hammersmith Hospital Campus, London W12 0NN, UK,To whom correspondence should be addressed; PO Box 053, Institute of Psychiatry, King's College London, De Crespigny Park, London, SE5 8AF, UK; tel: +44-20-7848-0593, fax: +44-20-7848-0287, e-mail:
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Hadjiconstantinou M, Neff NH. Enhancing aromatic L-amino acid decarboxylase activity: implications for L-DOPA treatment in Parkinson's disease. CNS Neurosci Ther 2009; 14:340-51. [PMID: 19040557 DOI: 10.1111/j.1755-5949.2008.00058.x] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
Aromatic L-amino acid decarboxylase (AAAD) is an essential enzyme for the formation of catecholamines, indolamines, and trace amines. Moreover, it is a required enzyme for converting L-DOPA to dopamine when treating patients with Parkinson's disease (PD). There is now substantial evidence that the activity of AAAD in striatum is regulated by activation and induction, and second messengers play a role. Enzyme activity can be modulated by drugs acting on a number of neurotransmitter receptors including dopamine (D1-4), glutamate (NMDA), serotonin (5-HT(1A), 5-HT(2A)) and nicotinic acetylcholine receptors. Generally, antagonists enhance AAAD activity; while, agonists may diminish it. Enhancement of AAAD activity is functional, as the formation of dopamine from exogenous L-DOPA mirrors activity. Following a lesion of nigrostriatal dopaminergic neurons, AAAD in striatum responds more robustly to pharmacological manipulations, and this is true for the decarboxylation of exogenous L-DOPA as well. We review the evidence for parallel modulation of AAAD activity and L-DOPA decarboxylation and propose that this knowledge can be exploited to optimize the formation of dopamine from exogenous L-DOPA. This information can be used as a blue print for the design of novel L-DOPA treatment adjuvants to benefit patients with PD.
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Affiliation(s)
- Maria Hadjiconstantinou
- Division of Molecular Neuropsychopharmacology, Department of Psychiatry, College of Medicine, Ohio State University, Columbus, OH 43210, USA
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Striatal and extrastriatal D2/D3-receptor-binding properties of ziprasidone: a positron emission tomography study with [18F]Fallypride and [11C]raclopride (D2/D3-receptor occupancy of ziprasidone). J Clin Psychopharmacol 2008; 28:608-17. [PMID: 19011428 DOI: 10.1097/jcp.0b013e31818ba2f6] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
To elucidate the "atypicality" of ziprasidone, its striatal and extrastriatal D2/D3-receptor binding was characterized in patients with schizophrenia under steady-state conditions. These data were compared with striatal receptor occupancy values after single-dose ziprasidone ingestion in healthy controls. [F]fallypride positron emission tomography (PET) recordings were obtained in 15 patients under steady-state ziprasidone treatment at varying time points after the last dose. Binding potentials were calculated for striatal and extrastriatal regions. D2/D3-receptor occupancies were expressed relative to binding potentials in 8 unmedicated patients. In a parallel [C]raclopride-PET study, striatal D2/D3-receptor occupancy was measured in healthy subjects after single oral doses of 40 mg ziprasidone or 7.5 mg haloperidol. Ziprasidone plasma concentrations correlated significantly with D2/D3-receptor occupancies in all volumes of interests. Occupancy in extrastriatal regions was approximately 10% higher than in striatal regions. Half maximal effective concentration values were consistently higher in striatal than in extrastriatal regions (temporal cortex: 39 ng/mL; putamen: 64 ng/mL), irrespective of the time between last dosing and scan. Single ziprasidone doses resulted in higher occupancies exceeding the 95% prediction limits of the occupancy versus plasma concentrations for chronic dosing. Ziprasidone shares moderate preferential extrastriatal D2/D3-receptor binding with some other atypicals. D2/D3-receptor occupancy is rapidly attuning to the daily course of ziprasidone plasma levels, suggesting relatively high intraday variations of D2/D3-receptor binding. The discrepancies between single-dose and steady-state results are important for the future design of dose-finding PET occupancy studies of novel antipsychotics. Single-dose studies may not be totally relied on for final dose selection.
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Kumakura Y, Vernaleken I, Buchholz HG, Borghammer P, Danielsen E, Gründer G, Heinz A, Bartenstein P, Cumming P. Age-dependent decline of steady state dopamine storage capacity of human brain: an FDOPA PET study. Neurobiol Aging 2008; 31:447-63. [PMID: 18541344 DOI: 10.1016/j.neurobiolaging.2008.05.005] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2008] [Revised: 04/23/2008] [Accepted: 05/01/2008] [Indexed: 01/17/2023]
Abstract
Conventional indices of the utilization of FDOPA in living human brain have not consistently revealed important declines in dopamine function with normal aging. However, most methods of kinetic analysis have assumed irreversible trapping of decarboxylated FDOPA metabolites in brain, an assumption that is violated even in PET recordings of short duration. Therefore, we have developed methods for the calculation of steady-state storage of FDOPA together with its decarboxylated metabolites (V(d), mlg(-1)), based upon improved kinetic analysis of 120-min emission recordings. In a group of 28 normal male subjects, of age ranging from 23 to 73 years, the magnitude of V(d) in the striatum and in extrastriatal regions declined by approximately 10% with each decade. The utilization of FDOPA was also calculated by several conventional methods assuming irreversible trapping, i.e. the net blood brain clearance (K(in)(app), mlg(-1)min(-1)), the DOPA decarboxylase activity relative to a reference tissue input (k(3)(S), min(-1)), and relative to the arterial input (k(3)(D), min(-1)). None of these methods revealed an age-related decline in FDOPA utilization in the extended striatum, although the magnitude of K(in)(app) did decline in cerebral cortex. Thus, the capacity to synthesize [(18)F]fluorodopamine remained largely intact in striatum of the elderly subjects, but in the presence of a substantially increased rate of washout (k(loss)), which was evident in all brain regions examined. Consequently, the magnitude of V(d) declined with healthy aging, possibly reflecting impaired vesicular storage capacity, resulting in enhanced exposure of cytosolic [(18)F]fluorodopamine to monoamine oxidase.
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Affiliation(s)
- Yoshitaka Kumakura
- Centre for Functionally Integrative Neuroscience, Aarhus University, Aarhus C. 8000, Denmark.
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Vernaleken I, Kumakura Y, Buchholz HG, Siessmeier T, Hilgers RD, Bartenstein P, Cumming P, Gründer G. Baseline [18F]-FDOPA kinetics are predictive of haloperidol-induced changes in dopamine turnover and cognitive performance: A positron emission tomography study in healthy subjects. Neuroimage 2008; 40:1222-31. [PMID: 18262797 DOI: 10.1016/j.neuroimage.2007.12.045] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2007] [Revised: 12/23/2007] [Accepted: 12/28/2007] [Indexed: 10/22/2022] Open
Abstract
The telencephalic dopamine innervations contribute to the modulation of cognitive processing. However, the relationship between cognitive effects of D(2/3)-receptor antagonism and dopamine transmission is not described in healthy subjects. We therefore tested effects of acute haloperidol (5 mg/d over 3 days) on continuous performance task (CPT) performance and 6-[(18)F]-fluoro-l-DOPA (FDOPA) PET parameters. Nine physically and mentally healthy male men performed two FDOPA-PET scans including arterial plasma withdrawal. Over 3 days before the second scan, all subjects were treated with 5 mg/d haloperidol orally. Using our novel steady-state analysis, we calculated the intrinsic rate of the cerebral FDOPA utilization (K), the turnover of [(18)F]fluorodopamine formed in brain (k(loss)) and the storage for FDOPA and its brain metabolites (V(d)). Furthermore, a ds-CPT and EPS-screening was performed before every PET scan. We found that FDOPA kinetics in those normal subjects with relatively high baseline K showed a more pronounced sensitivity to haloperidol treatment, manifesting in reduced storage capacity and elevated turnover of [(18)F]fluorodopamine, whereas subjects with lower K showed the opposite pattern of responses. Furthermore, low baseline K predicted improvements in the CPT task after haloperidol, whereas participants with higher baseline K showed a decline in cognitive performance. We conclude that the initial increase of [(18)F]fluorodopamine turnover after acute haloperidol challenge is associated with an over-stimulation in individuals with initially more pharmacologically responsive dopamine systems, but optimizes cognitive performance in those with lower normal FDOPA utilization at baseline. We hypothesize that these effects may be driven by D(1)-receptor mediated transmission during D(2) blockade.
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Affiliation(s)
- Ingo Vernaleken
- Department of Psychiatry and Psychotherapy, RWTH Aachen University, Pauwelsstrasse 30, 52074 Aachen, Germany.
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Vernaleken I, Buchholz HG, Kumakura Y, Siessmeier T, Stoeter P, Bartenstein P, Cumming P, Gründer G. 'Prefrontal' cognitive performance of healthy subjects positively correlates with cerebral FDOPA influx: an exploratory [18F]-fluoro-L-DOPA-PET investigation. Hum Brain Mapp 2007; 28:931-9. [PMID: 17133402 PMCID: PMC6871482 DOI: 10.1002/hbm.20325] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Dopamine neurotransmission influences those cognitive processes, which are generally regarded as prefrontal cortical functions. In previous positron-emission-tomography (PET) studies, net blood-brain clearance of [18F]-fluoro-l-DOPA (FDOPA) correlated with impaired cognitive performance in patients with Parkinson's disease or schizophrenia. We hypothesized that FDOPA influx also correlates with performance of cognitive tasks associated with prefrontal functioning in healthy volunteers. The net blood-brain clearance of FDOPA (K(in)(app)) was mapped in a group of 11 healthy volunteers and calculated in striatal volumes-of-interest. The Wisconsin-Card-Sorting-Test (WCST), Stroop-Test, Trail-Making-Test (TMT-A/B), and Continuous-Performance-Test (CPT-M) had been administered previously to the same subjects. No correlation of K(in) (app) with perseverative errors in WCST or age could be found. However, there were significant positive correlations between the magnitude of K(in)(app) in caudate nucleus, putamen, and midbrain with performance of the TMT-B, CPT-M, and the Stroop test. Highest correlations were found between the time needed to perform the Stroop interference task and the K(in)(app) of striatal areas (Caudate nucleus: -0.780, P = 0.005; putamen: -0.870, P < 0. 001). Thus, the present findings reveal a strong correlation between dopamine synthesis capacity in striatum of healthy volunteers and performance of cognitive tasks linked to the prefrontal cortex.
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Affiliation(s)
- Ingo Vernaleken
- Department of Psychiatry and Psychotherapy, RWTH Aachen University, Aachen, Germany.
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Kumakura Y, Cumming P, Vernaleken I, Buchholz HG, Siessmeier T, Heinz A, Kienast T, Bartenstein P, Gründer G. Elevated [18F]fluorodopamine turnover in brain of patients with schizophrenia: an [18F]fluorodopa/positron emission tomography study. J Neurosci 2007; 27:8080-7. [PMID: 17652599 PMCID: PMC6672729 DOI: 10.1523/jneurosci.0805-07.2007] [Citation(s) in RCA: 111] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Previous positron emission tomography (PET) studies with levodopa analogs have revealed a modestly increased capacity for dopamine synthesis in the striatum of patients with schizophrenia compared with healthy age-matched control subjects. We hypothesized that not just the synthesis but also the turnover of radiolabeled dopamine is elevated in patients. To test the hypothesis, we reanalyzed 2-h-long [18F]fluorodopa (FDOPA)/PET recordings from eight unmedicated patients with schizophrenia and 15 healthy age-matched control subjects, using new methods for the quantification of [18F]fluorodopamine steady-state kinetics. The fractional rate constant for the catabolism and elimination of [18F]fluorodopamine was elevated nearly twofold in striatum, the largest biochemical difference in brain of schizophrenics yet reported. The magnitude of the intrinsic blood-brain FDOPA clearance with correction for this loss of [18F]fluorodopamine metabolites was increased by 20% in caudate and putamen and by 50% in amygdala and midbrain of the patients. However, the magnitude of the steady-state storage of FDOPA and its decarboxylated metabolites (V(d)) was reduced by one-third in the caudate nucleus and amygdala of the schizophrenic group. Thus, reduced steady-state storage of [18F]fluorodopamine occurs in the midst of accelerated synthesis in brain of untreated patients. Positive scores of the positive and negative syndrome scale correlated inversely with the magnitude of V(d) in amygdala, suggesting an association between positive symptoms and impaired steady-state storage of FDOPA metabolites in that structure.
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Affiliation(s)
- Yoshitaka Kumakura
- Centre for Functionally Integrative Neuroscience, Aarhus University, DK-8000 Aarhus C, Denmark.
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Lind NM, Moustgaard A, Jelsing J, Vajta G, Cumming P, Hansen AK. The use of pigs in neuroscience: Modeling brain disorders. Neurosci Biobehav Rev 2007; 31:728-51. [PMID: 17445892 DOI: 10.1016/j.neubiorev.2007.02.003] [Citation(s) in RCA: 365] [Impact Index Per Article: 21.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2006] [Revised: 02/05/2007] [Accepted: 02/18/2007] [Indexed: 11/22/2022]
Abstract
The use of pigs in neuroscience research has increased in the past decade, which has seen broader recognition of the potential of pigs as an animal for experimental modeling of human brain disorders. The volume of available background data concerning pig brain anatomy and neurochemistry has increased considerably in recent years. The pig brain, which is gyrencephalic, resembles the human brain more in anatomy, growth and development than do the brains of commonly used small laboratory animals. The size of the pig brain permits the identification of cortical and subcortical structures by imaging techniques. Furthermore, the pig is an increasingly popular laboratory animal for transgenic manipulations of neural genes. The present paper focuses on evaluating the potential for modeling symptoms, phenomena or constructs of human brain diseases in pigs, the neuropsychiatric disorders in particular. Important practical and ethical aspects of the use of pigs as an experimental animal as pertaining to relevant in vivo experimental brain techniques are reviewed. Finally, current knowledge of aspects of behavioral processes including learning and memory are reviewed so as to complete the summary of the status of pigs as a species suitable for experimental models of diverse human brain disorders.
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Affiliation(s)
- Nanna Marie Lind
- Department of Experimental Medicine, University of Copenhagen, Panum Institute, Blegdamsvej 3B, Copenhagen N, Denmark.
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