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Sotoyama H, Namba H, Tohmi M, Nawa H. Schizophrenia Animal Modeling with Epidermal Growth Factor and Its Homologs: Their Connections to the Inflammatory Pathway and the Dopamine System. Biomolecules 2023; 13:biom13020372. [PMID: 36830741 PMCID: PMC9953688 DOI: 10.3390/biom13020372] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2023] [Revised: 02/10/2023] [Accepted: 02/12/2023] [Indexed: 02/18/2023] Open
Abstract
Epidermal growth factor (EGF) and its homologs, such as neuregulins, bind to ErbB (Her) receptor kinases and regulate glial differentiation and dopaminergic/GABAergic maturation in the brain and are therefore implicated in schizophrenia neuropathology involving these cell abnormalities. In this review, we summarize the biological activities of the EGF family and its neuropathologic association with schizophrenia, mainly overviewing our previous model studies and the related articles. Transgenic mice as well as the rat/monkey models established by perinatal challenges of EGF or its homologs consistently exhibit various behavioral endophenotypes relevant to schizophrenia. In particular, post-pubertal elevation in baseline dopaminergic activity may illustrate the abnormal behaviors relevant to positive and negative symptoms as well as to the timing of this behavioral onset. With the given molecular interaction and transactivation of ErbB receptor kinases with Toll-like receptors (TLRs), EGF/ErbB signals are recruited by viral infection and inflammatory diseases such as COVID-19-mediated pneumonia and poxvirus-mediated fibroma and implicated in the immune-inflammatory hypothesis of schizophrenia. Finally, we also discuss the interaction of clozapine with ErbB receptor kinases as well as new antipsychotic development targeting these receptors.
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Affiliation(s)
- Hidekazu Sotoyama
- Department of Molecular Neurobiology, Brain Research Institute, Niigata University, Niigata 951-8585, Japan
- Department of Physiology, School of Medicine, Niigata University, Niigata 951-8122, Japan
- Correspondence: (H.N.); (H.S.)
| | - Hisaaki Namba
- Department of Molecular Neurobiology, Brain Research Institute, Niigata University, Niigata 951-8585, Japan
- Department of Physiological Sciences, School of Pharmaceutical Sciences, Wakayama Medical University, Wakayama 649-8156, Japan
| | - Manavu Tohmi
- Department of Physiological Sciences, School of Pharmaceutical Sciences, Wakayama Medical University, Wakayama 649-8156, Japan
| | - Hiroyuki Nawa
- Department of Molecular Neurobiology, Brain Research Institute, Niigata University, Niigata 951-8585, Japan
- Department of Physiological Sciences, School of Pharmaceutical Sciences, Wakayama Medical University, Wakayama 649-8156, Japan
- Correspondence: (H.N.); (H.S.)
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Hegarty CE, Ianni AM, Kohn PD, Kolachana B, Gregory M, Masdeu JC, Eisenberg DP, Berman KF. Polymorphism in the ZNF804A Gene and Variation in D 1 and D 2/D 3 Dopamine Receptor Availability in the Healthy Human Brain: A Dual Positron Emission Tomography Study. BIOLOGICAL PSYCHIATRY. COGNITIVE NEUROSCIENCE AND NEUROIMAGING 2023; 8:121-128. [PMID: 33712377 PMCID: PMC10501410 DOI: 10.1016/j.bpsc.2020.12.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/13/2020] [Revised: 12/03/2020] [Accepted: 12/15/2020] [Indexed: 01/11/2023]
Abstract
BACKGROUND The rs1344706 single nucleotide polymorphism in the ZNF804A gene has been associated with risk for psychosis in multiple genome-wide association studies, yet mechanisms underlying this association are not known. Given preclinical work suggesting an impact of ZNF804A on dopamine receptor gene transcription and clinical studies establishing dopaminergic dysfunction in patients with schizophrenia, we hypothesized that the ZNF804A risk single nucleotide polymorphism would be associated with variation in dopamine receptor availability in the human brain. METHODS In this study, 72 healthy individuals genotyped for rs1344706 completed both [18F]fallypride and [11C]NNC-112 positron emission tomography scans to measure D2/D3 and D1 receptor availability, respectively. Genetic effects on estimates of binding potential for each ligand were tested first with canonical subject-specific striatal regions of interest analyses, followed by exploratory whole-brain voxelwise analyses to test for more localized striatal signals and for extrastriatal effects. RESULTS Region of interest analyses revealed significantly less D2/D3 receptor availability in risk-allele homozygotes (TT) compared with non-risk allele carriers (G-allele carrier group: TG and GG) in the associative striatum and sensorimotor striatum, but no significant differences in striatal D1 receptor availability. CONCLUSIONS These data suggest that ZNF804A genotype may be meaningfully linked to dopaminergic function in the human brain. The results also may provide information to guide future studies of ZNF804A-related mechanisms of schizophrenia risk.
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Affiliation(s)
- Catherine E Hegarty
- Clinical and Translational Neuroscience Branch, Intramural Research Program, National Institute of Mental Health, National Institutes of Health, Department of Health and Human Services, Bethesda, Maryland; Neuroscience Graduate Program, Brown University, Providence, Rhode Island
| | - Angela M Ianni
- Clinical and Translational Neuroscience Branch, Intramural Research Program, National Institute of Mental Health, National Institutes of Health, Department of Health and Human Services, Bethesda, Maryland
| | - Philip D Kohn
- Clinical and Translational Neuroscience Branch, Intramural Research Program, National Institute of Mental Health, National Institutes of Health, Department of Health and Human Services, Bethesda, Maryland
| | - Bhaskar Kolachana
- Human Brain Collection Core, Intramural Research Program, National Institute of Mental Health, National Institutes of Health, Department of Health and Human Services, Bethesda, Maryland
| | - Michael Gregory
- Clinical and Translational Neuroscience Branch, Intramural Research Program, National Institute of Mental Health, National Institutes of Health, Department of Health and Human Services, Bethesda, Maryland
| | - Joseph C Masdeu
- Clinical and Translational Neuroscience Branch, Intramural Research Program, National Institute of Mental Health, National Institutes of Health, Department of Health and Human Services, Bethesda, Maryland
| | - Daniel P Eisenberg
- Clinical and Translational Neuroscience Branch, Intramural Research Program, National Institute of Mental Health, National Institutes of Health, Department of Health and Human Services, Bethesda, Maryland
| | - Karen F Berman
- Clinical and Translational Neuroscience Branch, Intramural Research Program, National Institute of Mental Health, National Institutes of Health, Department of Health and Human Services, Bethesda, Maryland.
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Barret O, Zhang L, Alagille D, Constantinescu CC, Sandiego C, Papin C, Sullivan JM, Morley T, Carroll VM, Seibyl J, Chen J, Lee C, Villalobos A, Gray D, McCarthy TJ, Tamagnan G. Dopamine D 1 Receptor Agonist PET Tracer Development: Assessment in Nonhuman Primates. J Nucl Med 2021; 62:1307-1313. [PMID: 33579806 DOI: 10.2967/jnumed.120.256008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2020] [Accepted: 12/22/2020] [Indexed: 11/16/2022] Open
Abstract
Non-catechol-based high-affinity selective dopamine D1 receptor (D1R) agonists were recently described, and candidate PET ligands were selected on the basis of favorable properties. The objective of this study was to characterize in vivo in nonhuman primates 2 novel D1R agonist PET radiotracers, racemic 18F-MNI-800 and its more active atropisomeric (-)-enantiomer, 18F-MNI-968. Methods: Ten brain PET experiments were conducted with 18F-MNI-800 on 2 adult rhesus macaques and 2 adult cynomolgus macaques, and 8 brain PET experiments were conducted with 18F-MNI-968 on 2 adult rhesus macaques and 2 adult cynomolgus macaques. PET data were analyzed with both plasma-input-based methods and reference-region-based methods. Whole-body PET images were acquired with 18F-MNI-800 from 2 adult rhesus macaques for radiation dosimetry estimates. Results: 18F-MNI-800 and 18F-MNI-968 exhibited regional uptake consistent with D1R distribution. Specificity and selectivity were demonstrated by dose-dependent blocking with the D1 antagonist SCH-23390. 18F-MNI-968 showed a 30% higher specific signal than 18F-MNI-800, with a nondisplaceable binding potential of approximately 0.3 in the cortex and approximately 1.1 in the striatum. Dosimetry radiation exposure was favorable, with an effective dose of about 0.023 mSv/MBq. Conclusion: 18F-MNI-968 has significant potential as a D1R agonist PET radiotracer, and further characterization in human subjects is warranted.
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Affiliation(s)
- Olivier Barret
- Invicro, LLC, New Haven, Connecticut; .,Université Paris-Saclay, CEA, CNRS, MIRCen, Laboratoire des Maladies Neurodégénératives, Fontenay-aux-Roses, France
| | - Lei Zhang
- Medicine Design, Medicinal Chemistry, Pfizer Inc., Cambridge, Massachusetts
| | - David Alagille
- Invicro, LLC, New Haven, Connecticut.,Xing Imaging, New Haven, Connecticut
| | | | | | | | | | | | | | | | - Jianqing Chen
- Digital Medicine and Imaging, Early Clinical Development, Pfizer Inc., Cambridge, Massachusetts; and
| | - Chewah Lee
- Medicine Design, Medicinal Chemistry, Pfizer Inc., Cambridge, Massachusetts
| | | | - David Gray
- Medicine Design, Medicinal Chemistry, Pfizer Inc., Cambridge, Massachusetts.,Cerevel Therapeutics, Boston, Massachusetts
| | - Timothy J McCarthy
- Digital Medicine and Imaging, Early Clinical Development, Pfizer Inc., Cambridge, Massachusetts; and
| | - Gilles Tamagnan
- Invicro, LLC, New Haven, Connecticut.,Xing Imaging, New Haven, Connecticut
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4
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Abi-Dargham A, Javitch JA, Slifstein M, Anticevic A, Calkins ME, Cho YT, Fonteneau C, Gil R, Girgis R, Gur RE, Gur RC, Grinband J, Kantrowitz J, Kohler C, Krystal J, Murray J, Ranganathan M, Santamauro N, Van Snellenberg J, Tamayo Z, Wolf D, Gray D, Lieberman J. Dopamine D1R Receptor Stimulation as a Mechanistic Pro-cognitive Target for Schizophrenia. Schizophr Bull 2021; 48:199-210. [PMID: 34423843 PMCID: PMC8781338 DOI: 10.1093/schbul/sbab095] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Decades of research have highlighted the importance of optimal stimulation of cortical dopaminergic receptors, particularly the D1R receptor (D1R), for prefrontal-mediated cognition. This mechanism is particularly relevant to the cognitive deficits in schizophrenia, given the abnormalities in cortical dopamine (DA) neurotransmission and in the expression of D1R. Despite the critical need for D1R-based therapeutics, many factors have complicated their development and prevented this important therapeutic target from being adequately interrogated. Challenges include determination of the optimal level of D1R stimulation needed to improve cognitive performance, especially when D1R expression levels, affinity states, DA levels, and the resulting D1R occupancy by DA, are not clearly known in schizophrenia, and may display great interindividual and intraindividual variability related to cognitive states and other physiological variables. These directly affect the selection of the level of stimulation necessary to correct the underlying neurobiology. The optimal mechanism for stimulation is also unknown and could include partial or full agonism, biased agonism, or positive allosteric modulation. Furthermore, the development of D1R targeting drugs has been complicated by complexities in extrapolating from in vitro affinity determinations to in vivo use. Prior D1R-targeted drugs have been unsuccessful due to poor bioavailability, pharmacokinetics, and insufficient target engagement at tolerable doses. Newer drugs have recently become available, and these must be tested in the context of carefully designed paradigms that address methodological challenges. In this paper, we discuss how a better understanding of these challenges has shaped our proposed experimental design for testing a new D1R/D5R partial agonist, PF-06412562, renamed CVL-562.
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Affiliation(s)
- Anissa Abi-Dargham
- Department of Psychiatry, Stony Brook Renaissance School of Medicine, Stony Brook, NY, USA,Department of Psychiatry, New York State Psychaitric Institute, Columbia University, New York, NY, USA,Department of Psychiatry, Yale University, New Haven, CT, USA,Department of Psychiatry, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA,Cerevel Therapeutics Research and Development, Boston, MA, USA,To whom correspondence should be addressed; Tel: +(631) 885-0814; e-mail:
| | - Jonathan A Javitch
- Department of Psychiatry, New York State Psychaitric Institute, Columbia University, New York, NY, USA
| | - Mark Slifstein
- Department of Psychiatry, Stony Brook Renaissance School of Medicine, Stony Brook, NY, USA
| | - Alan Anticevic
- Department of Psychiatry, Yale University, New Haven, CT, USA
| | - Monica E Calkins
- Department of Psychiatry, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Youngsun T Cho
- Department of Psychiatry, Yale University, New Haven, CT, USA
| | - Clara Fonteneau
- Department of Psychiatry, Yale University, New Haven, CT, USA
| | - Roberto Gil
- Department of Psychiatry, Stony Brook Renaissance School of Medicine, Stony Brook, NY, USA
| | - Ragy Girgis
- Department of Psychiatry, New York State Psychaitric Institute, Columbia University, New York, NY, USA
| | - Raquel E Gur
- Department of Psychiatry, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Ruben C Gur
- Department of Psychiatry, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Jack Grinband
- Department of Psychiatry, New York State Psychaitric Institute, Columbia University, New York, NY, USA
| | - Joshua Kantrowitz
- Department of Psychiatry, New York State Psychaitric Institute, Columbia University, New York, NY, USA
| | - Christian Kohler
- Department of Psychiatry, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - John Krystal
- Department of Psychiatry, Yale University, New Haven, CT, USA
| | - John Murray
- Department of Psychiatry, Yale University, New Haven, CT, USA
| | | | | | - Jared Van Snellenberg
- Department of Psychiatry, Stony Brook Renaissance School of Medicine, Stony Brook, NY, USA
| | - Zailyn Tamayo
- Department of Psychiatry, Yale University, New Haven, CT, USA
| | - Daniel Wolf
- Department of Psychiatry, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | | | - David Gray
- Cerevel Therapeutics Research and Development, Boston, MA, USA
| | - Jeffrey Lieberman
- Department of Psychiatry, New York State Psychaitric Institute, Columbia University, New York, NY, USA
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16p11.2 deletion is associated with hyperactivation of human iPSC-derived dopaminergic neuron networks and is rescued by RHOA inhibition in vitro. Nat Commun 2021; 12:2897. [PMID: 34006844 PMCID: PMC8131375 DOI: 10.1038/s41467-021-23113-z] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2020] [Accepted: 04/16/2021] [Indexed: 02/03/2023] Open
Abstract
Reciprocal copy number variations (CNVs) of 16p11.2 are associated with a wide spectrum of neuropsychiatric and neurodevelopmental disorders. Here, we use human induced pluripotent stem cells (iPSCs)-derived dopaminergic (DA) neurons carrying CNVs of 16p11.2 duplication (16pdup) and 16p11.2 deletion (16pdel), engineered using CRISPR-Cas9. We show that 16pdel iPSC-derived DA neurons have increased soma size and synaptic marker expression compared to isogenic control lines, while 16pdup iPSC-derived DA neurons show deficits in neuronal differentiation and reduced synaptic marker expression. The 16pdel iPSC-derived DA neurons have impaired neurophysiological properties. The 16pdel iPSC-derived DA neuronal networks are hyperactive and have increased bursting in culture compared to controls. We also show that the expression of RHOA is increased in the 16pdel iPSC-derived DA neurons and that treatment with a specific RHOA-inhibitor, Rhosin, rescues the network activity of the 16pdel iPSC-derived DA neurons. Our data suggest that 16p11.2 deletion-associated iPSC-derived DA neuron hyperactivation can be rescued by RHOA inhibition.
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Boczek T, Mackiewicz J, Sobolczyk M, Wawrzyniak J, Lisek M, Ferenc B, Guo F, Zylinska L. The Role of G Protein-Coupled Receptors (GPCRs) and Calcium Signaling in Schizophrenia. Focus on GPCRs Activated by Neurotransmitters and Chemokines. Cells 2021; 10:cells10051228. [PMID: 34067760 PMCID: PMC8155952 DOI: 10.3390/cells10051228] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Revised: 05/12/2021] [Accepted: 05/14/2021] [Indexed: 01/13/2023] Open
Abstract
Schizophrenia is a common debilitating disease characterized by continuous or relapsing episodes of psychosis. Although the molecular mechanisms underlying this psychiatric illness remain incompletely understood, a growing body of clinical, pharmacological, and genetic evidence suggests that G protein-coupled receptors (GPCRs) play a critical role in disease development, progression, and treatment. This pivotal role is further highlighted by the fact that GPCRs are the most common targets for antipsychotic drugs. The GPCRs activation evokes slow synaptic transmission through several downstream pathways, many of them engaging intracellular Ca2+ mobilization. Dysfunctions of the neurotransmitter systems involving the action of GPCRs in the frontal and limbic-related regions are likely to underly the complex picture that includes the whole spectrum of positive and negative schizophrenia symptoms. Therefore, the progress in our understanding of GPCRs function in the control of brain cognitive functions is expected to open new avenues for selective drug development. In this paper, we review and synthesize the recent data regarding the contribution of neurotransmitter-GPCRs signaling to schizophrenia symptomology.
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Affiliation(s)
- Tomasz Boczek
- Department of Molecular Neurochemistry, Faculty of Health Sciences, Medical University of Lodz, 92215 Lodz, Poland; (T.B.); (J.M.); (M.S.); (J.W.); (M.L.); (B.F.)
| | - Joanna Mackiewicz
- Department of Molecular Neurochemistry, Faculty of Health Sciences, Medical University of Lodz, 92215 Lodz, Poland; (T.B.); (J.M.); (M.S.); (J.W.); (M.L.); (B.F.)
| | - Marta Sobolczyk
- Department of Molecular Neurochemistry, Faculty of Health Sciences, Medical University of Lodz, 92215 Lodz, Poland; (T.B.); (J.M.); (M.S.); (J.W.); (M.L.); (B.F.)
| | - Julia Wawrzyniak
- Department of Molecular Neurochemistry, Faculty of Health Sciences, Medical University of Lodz, 92215 Lodz, Poland; (T.B.); (J.M.); (M.S.); (J.W.); (M.L.); (B.F.)
| | - Malwina Lisek
- Department of Molecular Neurochemistry, Faculty of Health Sciences, Medical University of Lodz, 92215 Lodz, Poland; (T.B.); (J.M.); (M.S.); (J.W.); (M.L.); (B.F.)
| | - Bozena Ferenc
- Department of Molecular Neurochemistry, Faculty of Health Sciences, Medical University of Lodz, 92215 Lodz, Poland; (T.B.); (J.M.); (M.S.); (J.W.); (M.L.); (B.F.)
| | - Feng Guo
- Department of Pharmaceutical Toxicology, School of Pharmacy, China Medical University, Shenyang 110122, China;
| | - Ludmila Zylinska
- Department of Molecular Neurochemistry, Faculty of Health Sciences, Medical University of Lodz, 92215 Lodz, Poland; (T.B.); (J.M.); (M.S.); (J.W.); (M.L.); (B.F.)
- Correspondence:
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Differential effects of d- and l-enantiomers of govadine on distinct forms of cognitive flexibility and a comparison with dopaminergic drugs. Psychopharmacology (Berl) 2021; 238:1069-1085. [PMID: 33432392 DOI: 10.1007/s00213-020-05754-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/22/2020] [Accepted: 12/21/2020] [Indexed: 10/22/2022]
Abstract
RATIONALE There is an urgent need for novel drugs for treating cognitive deficits that are defining features of schizophrenia. The individual d- and l-enantiomers of the tetrahydroprotoberberine (THPB) d,l-govadine have been proposed for the treatment of cognitive deficiencies and positive symptoms of schizophrenia, respectively. OBJECTIVES We examined the effects of d-, l-, or d,l-govadine on two distinct forms of cognitive flexibility perturbed in schizophrenia and compared them to those induced by a selective D1 receptor agonist and D2 receptor antagonist. METHODS Male rats received d-, l-, or d,l-govadine (0.3, 0.5, and 1.0 mg/kg), D1 agonist SKF81297(0.1, 0.3, and 1.0 mg/kg), or D2 antagonist haloperidol (0.1-0.2 mg/kg). Experiment 1 used a strategy set-shifting task (between-subjects). In experiment 2, well-trained rats were tested on a probabilistic reversal task (within-subjects). RESULTS d-Govadine improved set-shifting across all doses, whereas higher doses of l-govadine impaired set-shifting. SKF81297 reduced perseverative errors at the lowest dose. Low/high doses of haloperidol increased/decreased set-shifting errors, the latter "improvement" attributable to impaired retrieval of a previous acquired rule. Probabilistic reversal performance was less affected by these drugs, but d-govadine reduced errors during the first reversal, whereas l-govadine impaired initial discrimination learning. d,l-Govadine had no reliable cognitive effects but caused psychomotor slowing like l-govadine and haloperidol. CONCLUSIONS These findings further highlight differences between two enantiomers of d,l-govadine that may reflect differential modulation of D1 and D2 receptors. These preclinical findings give further impetus to formal clinical evaluation of d-govadine as a treatment for cognitive deficiencies related to schizophrenia.
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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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Tryon VL, Garman HD, Loewy RL, Niendam TA. Links Between Human and Animal Models of Trauma and Psychosis: A Narrative Review. BIOLOGICAL PSYCHIATRY: COGNITIVE NEUROSCIENCE AND NEUROIMAGING 2020; 6:154-165. [PMID: 33309566 DOI: 10.1016/j.bpsc.2020.09.012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Revised: 09/08/2020] [Accepted: 09/16/2020] [Indexed: 11/26/2022]
Abstract
Traumatic experiences during development are associated with an increased risk of developing psychosis. Individuals with psychosis also report a higher rate of past trauma than healthy control subjects and worse outcomes than those who do not have these experiences. It is thought that traumatic experiences negatively impact specific neurobiological processes to confer this increased risk, and that systems affected by trauma are similarly changed in individuals with psychosis. Examining animal models of psychosis and the shared neurobiological changes in response to stressors can offer valuable insight into biological mechanisms that mediate symptoms and targets for intervention. This targeted review highlights a subset of models of psychosis across humans and animals, examines the similarities with the brain's response to stress and traumatic events, and discusses how these models may interact. Suggestions for future research are described.
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Affiliation(s)
- Valerie L Tryon
- Department of Psychiatry and Behavioral Sciences, University of California, Davis, Davis
| | - Heather D Garman
- Department of Psychiatry, Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, California
| | - Rachel L Loewy
- Department of Psychiatry, Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, California
| | - Tara A Niendam
- Department of Psychiatry and Behavioral Sciences, University of California, Davis, Davis.
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Matheson GJ, Plavén-Sigray P, Louzolo A, Borg J, Farde L, Petrovic P, Cervenka S. Dopamine D1 receptor availability is not associated with delusional ideation measures of psychosis proneness. Schizophr Res 2020; 222:175-184. [PMID: 32616361 DOI: 10.1016/j.schres.2020.06.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/28/2020] [Revised: 05/25/2020] [Accepted: 06/01/2020] [Indexed: 10/24/2022]
Abstract
The dopamine D1 receptor (D1R) is thought to play a role in psychosis and schizophrenia, however positron emission tomography studies comparing patients and controls have been inconsistent. To circumvent some of the limitations of clinical studies, such as antipsychotic exposure, an alternative approach is to examine subclinical psychotic symptoms within the general population, i.e. psychosis proneness traits. In this study, we investigated whether D1R availability is associated with delusional ideation in healthy controls, in four experiments, using [11C]SCH23390 PET (n = 76) and psychometric questionnaires (n = 217). We performed exploratory analyses, direct self-replication, and confirmatory analyses using Bayesian statistical modelling. Collectively, we found strong evidence that there is little to no linear association between delusional ideation and D1R. If hypothesised changes in D1R in drug-naive psychosis patients can be confirmed, our results suggest that they may either occur at disease onset, or that they are associated with specific aspects of psychosis other than delusional ideation.
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Affiliation(s)
- Granville J Matheson
- Department of Clinical Neuroscience, Center for Psychiatry Research, Karolinska Institutet and Stockholm County Council, SE-171 76 Stockholm, Sweden.
| | - Pontus Plavén-Sigray
- Department of Clinical Neuroscience, Center for Psychiatry Research, Karolinska Institutet and Stockholm County Council, SE-171 76 Stockholm, Sweden
| | - Anaïs Louzolo
- Department of Clinical Neuroscience, Karolinska Institutet, SE-171 76 Stockholm, Sweden
| | - Jacqueline Borg
- Department of Clinical Neuroscience, Center for Psychiatry Research, Karolinska Institutet and Stockholm County Council, SE-171 76 Stockholm, Sweden
| | - Lars Farde
- Department of Clinical Neuroscience, Center for Psychiatry Research, Karolinska Institutet and Stockholm County Council, SE-171 76 Stockholm, Sweden; PET Science Centre, Precision Medicine and Genomics, IMED Biotech Unit, AstraZeneca, Karolinska Institutet, Sweden
| | - Predrag Petrovic
- Department of Clinical Neuroscience, Karolinska Institutet, SE-171 76 Stockholm, Sweden
| | - Simon Cervenka
- Department of Clinical Neuroscience, Center for Psychiatry Research, Karolinska Institutet and Stockholm County Council, SE-171 76 Stockholm, Sweden
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Vidal PM, Pacheco R. The Cross-Talk Between the Dopaminergic and the Immune System Involved in Schizophrenia. Front Pharmacol 2020; 11:394. [PMID: 32296337 PMCID: PMC7137825 DOI: 10.3389/fphar.2020.00394] [Citation(s) in RCA: 45] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2019] [Accepted: 03/16/2020] [Indexed: 12/14/2022] Open
Abstract
Dopamine is one of the neurotransmitters whose transmission is altered in a number of neural pathways in the brain of schizophrenic patients. Current evidence indicates that these alterations involve hyperactive dopaminergic transmission in mesolimbic areas, striatum, and hippocampus, whereas hypoactive dopaminergic transmission has been reported in the prefrontal cortex of schizophrenic patients. Consequently, schizophrenia is associated with several cognitive and behavioral alterations. Of note, the immune system has been found to collaborate with the central nervous system in a number of cognitive and behavioral functions, which are dysregulated in schizophrenia. Moreover, emerging evidence has associated schizophrenia and inflammation. Importantly, different lines of evidence have shown dopamine as a major regulator of inflammation. In this regard, dopamine might exert strong regulation in the activity, migration, differentiation, and proliferation of immune cells that have been shown to contribute to cognitive functions, including T-cells, microglial cells, and peripheral monocytes. Thereby, alterations in dopamine levels associated to schizophrenia might affect inflammatory response of immune cells and consequently some behavioral functions, including reference memory, learning, social behavior, and stress resilience. Altogether these findings support the involvement of an active cross-talk between the dopaminergic and immune systems in the physiopathology of schizophrenia. In this review we summarize, integrate, and discuss the current evidence indicating the involvement of an altered dopaminergic regulation of immunity in schizophrenia.
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Affiliation(s)
- Pia M Vidal
- Department of Basic Science, Biomedical Science Research Lab, Faculty of Medicine, Universidad Católica de la Santísima Concepción, Concepción, Chile.,Laboratorio de Neuroinmunología, Fundación Ciencia & Vida, Santiago, Chile
| | - Rodrigo Pacheco
- Laboratorio de Neuroinmunología, Fundación Ciencia & Vida, Santiago, Chile.,Universidad San Sebastián, Santiago, Chile
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12
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McCutcheon RA, Krystal JH, Howes OD. Dopamine and glutamate in schizophrenia: biology, symptoms and treatment. World Psychiatry 2020; 19:15-33. [PMID: 31922684 PMCID: PMC6953551 DOI: 10.1002/wps.20693] [Citation(s) in RCA: 252] [Impact Index Per Article: 63.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Glutamate and dopamine systems play distinct roles in terms of neuronal signalling, yet both have been proposed to contribute significantly to the pathophysiology of schizophrenia. In this paper we assess research that has implicated both systems in the aetiology of this disorder. We examine evidence from post-mortem, preclinical, pharmacological and in vivo neuroimaging studies. Pharmacological and preclinical studies implicate both systems, and in vivo imaging of the dopamine system has consistently identified elevated striatal dopamine synthesis and release capacity in schizophrenia. Imaging of the glutamate system and other aspects of research on the dopamine system have produced less consistent findings, potentially due to methodological limitations and the heterogeneity of the disorder. Converging evidence indicates that genetic and environmental risk factors for schizophrenia underlie disruption of glutamatergic and dopaminergic function. However, while genetic influences may directly underlie glutamatergic dysfunction, few genetic risk variants directly implicate the dopamine system, indicating that aberrant dopamine signalling is likely to be predominantly due to other factors. We discuss the neural circuits through which the two systems interact, and how their disruption may cause psychotic symptoms. We also discuss mechanisms through which existing treatments operate, and how recent research has highlighted opportunities for the development of novel pharmacological therapies. Finally, we consider outstanding questions for the field, including what remains unknown regarding the nature of glutamate and dopamine function in schizophrenia, and what needs to be achieved to make progress in developing new treatments.
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Affiliation(s)
- Robert A McCutcheon
- Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK
- MRC London Institute of Medical Sciences, Imperial College London, Hammersmith Hospital, London, UK
- South London and Maudsley Foundation NHS Trust, Maudsley Hospital, London, UK
| | - John H Krystal
- Department of Radiology and Biomedical Imaging, Yale University School of Medicine, New Haven, CT, USA
- Department of Psychiatry, Yale University School of Medicine, New Haven, CT, USA
- VA National Center for PTSD, VA Connecticut Healthcare System, West Haven, CT, USA
| | - Oliver D Howes
- Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK
- MRC London Institute of Medical Sciences, Imperial College London, Hammersmith Hospital, London, UK
- South London and Maudsley Foundation NHS Trust, Maudsley Hospital, London, UK
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13
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SPECT and PET of the Brain. Clin Nucl Med 2020. [DOI: 10.1007/978-3-030-39457-8_4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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14
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Hansson AC, Gründer G, Hirth N, Noori HR, Spanagel R, Sommer WH. Dopamine and opioid systems adaptation in alcoholism revisited: Convergent evidence from positron emission tomography and postmortem studies. Neurosci Biobehav Rev 2019; 106:141-164. [DOI: 10.1016/j.neubiorev.2018.09.010] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2018] [Revised: 09/08/2018] [Accepted: 09/14/2018] [Indexed: 12/20/2022]
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15
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Schneider ML, Moore CF, Ahlers EO, Barnhart TE, Christian BT, DeJesus OT, Engle JW, Holden JE, Larson JA, Moirano JM, Murali D, Nickles RJ, Resch LM, Converse AK. PET Measures of D1, D2, and DAT Binding Are Associated With Heightened Tactile Responsivity in Rhesus Macaques: Implications for Sensory Processing Disorder. Front Integr Neurosci 2019; 13:29. [PMID: 31379528 PMCID: PMC6652150 DOI: 10.3389/fnint.2019.00029] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2019] [Accepted: 07/02/2019] [Indexed: 01/11/2023] Open
Abstract
Sensory processing disorder (SPD), a developmental regulatory condition characterized by marked under- or over-responsivity to non-noxious sensory stimulation, is a common but poorly understood disorder that can profoundly affect mood, cognition, social behavior and adaptive life skills. Little is known about the etiology and neural underpinnings. Clinical research indicates that children with SPD show greater prevalence of difficulties in complex cognitive behavior including working memory, behavioral flexibility, and regulation of sensory and affective functions, which are related to prefrontal cortex (PFC), striatal, and midbrain regions. Neuroimaging may provide insight into mechanisms underlying SPD, and animal experiments provide important evidence that is not available in human studies. Rhesus monkeys (N = 73) were followed over a 20-year period from birth into old age. We focused on a single sensory modality, the tactile system, measured at 5-7 years, because of its critical importance for nourishment, attachment, and social reward in development. Positron emission tomography imaging was conducted at ages 12-18 years to quantify the availability of the D1 and D2 subtypes of the DA receptor (D1R and D2R), and the DA transporter (DAT). Heightened tactile responsivity was related to (a) elevated D1R in PFC overall, including lateral, ventrolateral, medial, anterior cingulate (aCg), frontopolar, and orbitofrontal (OFC) subregions, as well as nucleus accumbens (Acb), (b) reduced D2R in aCg, OFC, and substantia nigra/ventral tegmental area, and (c) elevated DAT in putamen. These findings suggest a mechanism by which DA pathways may be altered in SPD. These pathways are associated with reward processing and pain regulation, providing top-down regulation of sensory and affective processes. The balance between top-down cognitive control in the PFC-Acb pathway and bottom-up motivational function of the VTA-Acb-PFC pathway is critical for successful adaptive function. An imbalance in these two systems might explain DA-related symptoms in children with SPD, including reduced top-down regulatory function and exaggerated responsivity to stimuli. These results provide more direct evidence that SPD may involve altered DA receptor and transporter function in PFC, striatal, and midbrain regions. More work is needed to extend these results to humans.
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Affiliation(s)
- Mary L Schneider
- Occupational Therapy Program, Department of Kinesiology, University of Wisconsin-Madison, Madison, WI, United States.,Harlow Center for Biological Psychology, University of Wisconsin-Madison, Madison, WI, United States
| | - Colleen F Moore
- Department of Psychology, University of Wisconsin-Madison, Madison, WI, United States.,Department of Psychology, Montana State University, Bozeman, MT, United States
| | - Elizabeth O Ahlers
- Waisman Center, University of Wisconsin-Madison, Madison, WI, United States
| | - Todd E Barnhart
- Department of Medical Physics, University of Wisconsin-Madison, Madison, WI, United States
| | - Bradley T Christian
- Department of Medical Physics, University of Wisconsin-Madison, Madison, WI, United States
| | - Onofre T DeJesus
- Department of Medical Physics, University of Wisconsin-Madison, Madison, WI, United States
| | - Jonathan W Engle
- Department of Medical Physics, University of Wisconsin-Madison, Madison, WI, United States
| | - James E Holden
- Department of Medical Physics, University of Wisconsin-Madison, Madison, WI, United States
| | - Julie A Larson
- Occupational Therapy Program, Department of Kinesiology, University of Wisconsin-Madison, Madison, WI, United States.,Harlow Center for Biological Psychology, University of Wisconsin-Madison, Madison, WI, United States
| | - Jeffrey M Moirano
- Department of Medical Physics, University of Wisconsin-Madison, Madison, WI, United States
| | - Dhanabalan Murali
- Department of Medical Physics, University of Wisconsin-Madison, Madison, WI, United States
| | - Robert J Nickles
- Department of Medical Physics, University of Wisconsin-Madison, Madison, WI, United States
| | - Leslie M Resch
- Occupational Therapy Program, Department of Kinesiology, University of Wisconsin-Madison, Madison, WI, United States.,Harlow Center for Biological Psychology, University of Wisconsin-Madison, Madison, WI, United States
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16
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Nikolaus S, Mamlins E, Hautzel H, Müller HW. Acute anxiety disorder, major depressive disorder, bipolar disorder and schizophrenia are related to different patterns of nigrostriatal and mesolimbic dopamine dysfunction. Rev Neurosci 2019; 30:381-426. [PMID: 30269107 DOI: 10.1515/revneuro-2018-0037] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2018] [Accepted: 06/30/2018] [Indexed: 11/15/2022]
Abstract
Dopamine (DA) receptor and transporter dysfunctions play a major role in the pathophysiology of neuropsychiatric diseases including anxiety disorder (AD), major depressive disorder (MDD), bipolar disorder (BD) in the manic (BDman) or depressive (BDdep) state and schizophrenia (SZ). We performed a PUBMED search, which provided a total of 239 in vivo imaging studies with either positron emission tomography (PET) or single-proton emission computed tomography (SPECT). In these studies, DA transporter binding, D1 receptor (R) binding, D2R binding, DA synthesis and/or DA release in patients with the primary diagnosis of acute AD (n=310), MDD (n=754), BDman (n=15), BDdep (n=49) or SZ (n=1532) were compared to healthy individuals. A retrospective analysis revealed that AD, MDD, BDman, BDdep and SZ differed as to affected brain region(s), affected synaptic constituent(s) and extent as well as direction of dysfunction in terms of either sensitization or desensitization of transporter and/or receptor binding sites. In contrast to AD and SZ, in MDD, BDman and BDdep, neostriatal DA function was normal, whereas MDD, BDman, and BDdep were characterized by the increased availability of prefrontal and frontal DA. In contrast to AD, MDD, BDman and BDdep, DA function in SZ was impaired throughout the nigrostriatal and mesolimbocortical system with an increased availability of DA in the striatothalamocortical and a decreased availability in the mesolimbocortical pathway.
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Affiliation(s)
- Susanne Nikolaus
- Clinic of Nuclear Medicine, University Hospital Düsseldorf, Heinrich Heine University, Moorenstr. 5, D-40225 Düsseldorf, Germany
| | - Eduards Mamlins
- Clinic of Nuclear Medicine, University Hospital Düsseldorf, Heinrich Heine University, Moorenstr. 5, D-40225 Düsseldorf, Germany
| | - Hubertus Hautzel
- Clinic of Nuclear Medicine, University Hospital Düsseldorf, Heinrich Heine University, Moorenstr. 5, D-40225 Düsseldorf, Germany
| | - Hans-Wilhelm Müller
- Clinic of Nuclear Medicine, University Hospital Düsseldorf, Heinrich Heine University, Moorenstr. 5, D-40225 Düsseldorf, Germany
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17
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Stenkrona P, Matheson GJ, Halldin C, Cervenka S, Farde L. D1-Dopamine Receptor Availability in First-Episode Neuroleptic Naive Psychosis Patients. Int J Neuropsychopharmacol 2019; 22:415-425. [PMID: 30958880 PMCID: PMC6600463 DOI: 10.1093/ijnp/pyz017] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/10/2019] [Revised: 03/12/2019] [Accepted: 04/05/2019] [Indexed: 01/02/2023] Open
Abstract
BACKGROUND Positron emission tomography studies examining differences in D1-dopamine receptor binding between control subjects and patients with schizophrenia have been inconsistent, reporting higher, lower, and no difference in the frontal cortex. Exposure to antipsychotic medication has been suggested to be a likely source of this heterogeneity, and thus there is a need for studies of patients at early stages of the disorder who have not been exposed to such drugs. METHODS Here, we compared 17 healthy control subjects and 18 first-episode neuroleptic naive patients with schizophrenia or schizophreniform psychosis using positron emission tomography and the D1-dopamine receptor radioligand [11C]SCH23390. RESULTS We observed a statistically significant difference in the dorsolateral prefrontal cortex. Contrary to our expectations, patients had less D1-dopamine receptor availability with a moderate effect size. In a Bayesian analysis, we show that the data are over 50 times more likely to have occurred under the decrease as opposed to the increase hypothesis. This effect was not global, as our analysis showed that the null hypothesis was preferred over either hypothesis in the striatum. CONCLUSIONS This investigation represents the largest single sample of neuroleptic-naive patients examined for D1-dopamine receptor availability using PET and suggests a reduction of prefrontal D1-dopamine receptor density in the pathophysiology of schizophrenia. However, further work will be required to reach a consensus.
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Affiliation(s)
- Per Stenkrona
- Department of Clinical Neuroscience, Centre for Psychiatry Research, Karolinska Institutet and Stockholm County Council, Stockholm, Sweden,Correspondence: Per Stenkrona, MD, Karolinska Institutet, Department of Clinical Neuroscience Karolinska University Hospital, R5:02 SE-171 76 Stockholm, Sweden ()
| | - Granville J Matheson
- Department of Clinical Neuroscience, Centre for Psychiatry Research, Karolinska Institutet and Stockholm County Council, Stockholm, Sweden
| | - Christer Halldin
- Department of Clinical Neuroscience, Centre for Psychiatry Research, Karolinska Institutet and Stockholm County Council, Stockholm, Sweden
| | - Simon Cervenka
- Department of Clinical Neuroscience, Centre for Psychiatry Research, Karolinska Institutet and Stockholm County Council, Stockholm, Sweden
| | - Lars Farde
- Department of Clinical Neuroscience, Centre for Psychiatry Research, Karolinska Institutet and Stockholm County Council, Stockholm, Sweden,PET Science Centre, Precision Medicine, R&D Oncology, AstraZeneca, Karolinska Institutet, Sweden
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18
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Rao N, Northoff G, Tagore A, Rusjan P, Kenk M, Wilson A, Houle S, Strafella A, Remington G, Mizrahi R. Impaired Prefrontal Cortical Dopamine Release in Schizophrenia During a Cognitive Task: A [11C]FLB 457 Positron Emission Tomography Study. Schizophr Bull 2019; 45:670-679. [PMID: 29878197 PMCID: PMC6483585 DOI: 10.1093/schbul/sby076] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Evidence from several lines of research suggests decreased dopamine release in the prefrontal cortex as the neurochemical correlates of cognitive deficits in schizophrenia (SCZ). However, in vivo examination of cortical hypodopaminergia using positron emission tomography (PET) during cognitive task performance in SCZ remains to be investigated. We examined dopamine release in anterior cingulate cortex (ACC) and dorsolateral prefrontal cortex (DLPFC), using PET while participants were performing a cognitive task. Thirteen drug-free patients with SCZ and 13 healthy volunteers (HV) matched for age and sex participated in the study. Data were acquired between 2011 and 2015. Two PET scans with [11C]FLB 457 were acquired while the participants were performing the Wisconsin Card Sorting Test (WCST) and a sensorimotor control task (SMCT). A magnetic resonance image was acquired for anatomical delineation. Differences in cortical dopamine release between SCZ and HV, indexed as percentage change in binding potential between WCST and SMCT (ΔBPND), were calculated in ACC and DLPFC. We observed significant differences in the ΔBPND in ACC (HV = 4.40 ± 6.00; SCZ = -11.48 ± 15.08; t = 3.52; P = .003) and a trend-level difference in ΔBPND in DLPFC (HV = -0.58 ± 8.45; SCZ = -7.79 ± 11.28; t = 1.84; P = .079), suggesting dopamine depletion in cortical brain regions in patients with SCZ while performing a cognitive task. These results provide the first in vivo evidence for reduced dopamine release or even dopamine depletion while performing cognitive task in ACC and DLPFC in patients with SCZ. The present results provide support for the frontal hypodopaminergia hypothesis of cognitive symptoms in SCZ.
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Affiliation(s)
- Naren Rao
- Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, ON, Canada,Department of Psychiatry, National Institute of Mental Health and Neurosciences, Bengaluru, Karnataka, India
| | - Georg Northoff
- Institute of Mental Health Research: Mind, Brain Imaging and Neuroethics, University of Ottawa, Ottawa, ON, Canada
| | - Abanti Tagore
- Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, ON, Canada
| | - Pablo Rusjan
- Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, ON, Canada
| | - Miran Kenk
- Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, ON, Canada
| | - Alan Wilson
- Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, ON, Canada
| | - Sylvain Houle
- Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, ON, Canada
| | - Antonio Strafella
- Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, ON, Canada
| | - Gary Remington
- Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, ON, Canada
| | - Romina Mizrahi
- Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, ON, Canada,To whom correspondence should be addressed; University of Toronto, Focus on Youth Psychosis Prevention (FYPP), Centre for Addiction and Mental Health, 250 College Street, Toronto, ON M5T 1R8 Canada; tel: 416-535-8501 ext. 34508, fax: 416-979-4656, e-mail:
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19
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Stenkrona P, Matheson GJ, Cervenka S, Sigray PP, Halldin C, Farde L. [ 11C]SCH23390 binding to the D 1-dopamine receptor in the human brain-a comparison of manual and automated methods for image analysis. EJNMMI Res 2018; 8:74. [PMID: 30069645 PMCID: PMC6070454 DOI: 10.1186/s13550-018-0416-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2018] [Accepted: 06/27/2018] [Indexed: 11/22/2022] Open
Abstract
Background The D1-dopamine receptor radioligand [11C]SCH23390 has been frequently used in PET studies. In drug-naïve patients with schizophrenia, the findings have been inconsistent, with decreases, increases, and no change in the frontal cortex D1-dopamine receptors. While these discrepancies are likely primarily due to a lack of statistical power in these studies, we speculated that an additional explanation may be the differences due to methods of image analysis between studies, affecting reliability as well as bias between groups. Methods Fifteen healthy subjects underwent two PET measurements with [11C]SCH23390 on the same day. The binding potential (BPND) was compared using a 95% confidence interval following manual and automated delineation of a region of interest (ROI) as well as with and without frame-by-frame realignment. Results Automated target region delineation produced lower BPND values, while automated delineation of the reference region yielded higher BPND values. However, no significant differences were observed for repeatability using automated and manual delineation methods. Frame-by-frame realignment generated higher BPND values and improved repeatability. Conclusions The results suggest that the choice of ROI delineation method is not an important factor for reliability, whereas the improved results following movement correction confirm its importance in PET image analysis. Realignment is therefore especially important for measurements in patient populations such as schizophrenia or Parkinson’s disease, where motion artifacts may be more prevalent. Electronic supplementary material The online version of this article (10.1186/s13550-018-0416-2) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Per Stenkrona
- Department of Clinical Neuroscience, Centre for Psychiatry Research, Karolinska University Hospital, Karolinska Institutet, R5:02, S-171 76, Stockholm, Sweden. .,Stockholm County Council, Stockholm, Sweden.
| | - Granville J Matheson
- Department of Clinical Neuroscience, Centre for Psychiatry Research, Karolinska University Hospital, Karolinska Institutet, R5:02, S-171 76, Stockholm, Sweden.,Stockholm County Council, Stockholm, Sweden
| | - Simon Cervenka
- Department of Clinical Neuroscience, Centre for Psychiatry Research, Karolinska University Hospital, Karolinska Institutet, R5:02, S-171 76, Stockholm, Sweden.,Stockholm County Council, Stockholm, Sweden
| | - Pontus Plavén Sigray
- Department of Clinical Neuroscience, Centre for Psychiatry Research, Karolinska University Hospital, Karolinska Institutet, R5:02, S-171 76, Stockholm, Sweden.,Stockholm County Council, Stockholm, Sweden
| | - Christer Halldin
- Department of Clinical Neuroscience, Centre for Psychiatry Research, Karolinska University Hospital, Karolinska Institutet, R5:02, S-171 76, Stockholm, Sweden.,Stockholm County Council, Stockholm, Sweden
| | - Lars Farde
- PET Science Centre, Precision Medicine and Genomics, IMED Biotech Unit, AstraZeneca, Karolinska Institutet, Stockholm, Sweden
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20
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Dopamine D1 receptor subtype mediates acute stress-induced dendritic growth in excitatory neurons of the medial prefrontal cortex and contributes to suppression of stress susceptibility in mice. Mol Psychiatry 2018; 23:1717-1730. [PMID: 28924188 DOI: 10.1038/mp.2017.177] [Citation(s) in RCA: 71] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/07/2017] [Revised: 06/18/2017] [Accepted: 07/28/2017] [Indexed: 12/12/2022]
Abstract
Dopamine in prefrontal cortices is implicated in cognitive and emotional functions, and the dysfunction of prefrontal dopamine has been associated with cognitive and emotional deficits in mental illnesses. These findings have led to clinical trials of dopamine-targeting drugs and brain imaging of dopamine receptors in patients with mental illnesses. Rodent studies have suggested that dopaminergic pathway projecting to the medial prefrontal cortex (mPFC) suppresses stress susceptibility. Although various types of mPFC neurons express several dopamine receptor subtypes, previous studies neither isolated a role of dopamine receptor subtype nor identified the site of its action in mPFC. Using social defeat stress (SDS) in mice, here we identified a role of dopamine D1 receptor subtype in mPFC excitatory neurons in suppressing stress susceptibility. Repeated social defeat stress (R-SDS) reduces the expression of D1 receptor subtype in mPFC of mice susceptible to R-SDS. Knockdown of D1 receptor subtype in whole neuronal populations or excitatory neurons in mPFC facilitates the induction of social avoidance by SDS. Single social defeat stress (S-SDS) induces D1 receptor-mediated extracellular signal-regulated kinase phosphorylation and c-Fos expression in mPFC neurons. Whereas R-SDS reduces dendritic lengths of mPFC layer II/III pyramidal neurons, S-SDS increases arborization and spines of apical dendrites of these neurons in a D1 receptor-dependent manner. Collectively, our findings show that D1 receptor subtype and related signaling in mPFC excitatory neurons mediate acute stress-induced dendritic growth of these neurons and contribute to suppression of stress susceptibility. Therefore, we propose that D1 receptor-mediated dendritic growth in mPFC excitatory neurons suppresses stress susceptibility.
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Abstract
The dopamine (DA) system is considered to be centrally involved in the pathophysiology of several major psychiatric disorders. Using positron emission tomography (PET), aberrations in dopamine D2/D3-receptors (D2-R) levels and uptake of the DA precursor FDOPA have been shown for schizophrenia, substance abuse and depression. Radioligands for the dopamine D1-receptor (D1-R) have been available for more than three decades, however this receptor subtype has received much less attention in psychiatry research. Here, studies investigating D1-R in psychiatric patients in comparison to healthy control subjects are summarized. Although small sample sizes, medication effects and heterogeneous methods of quantification limit the conclusions that can be drawn, the data is suggestive of higher levels of cortical D1-R in drug naïve patients with psychosis, and lower D1-R in patients with affective disorders. Data sharing and reanalysis using harmonized methodology are important next steps towards clarifying the role of D1-R in these disorders.
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Affiliation(s)
- Simon Cervenka
- Department of Clinical Neuroscience, Center for Psychiatry Research, Karolinska Institutet and Stockholm County Council, SE-171 76 Stockholm, Sweden.
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22
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23
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Weinstein JJ, Chohan MO, Slifstein M, Kegeles LS, Moore H, Abi-Dargham A. Pathway-Specific Dopamine Abnormalities in Schizophrenia. Biol Psychiatry 2017; 81:31-42. [PMID: 27206569 PMCID: PMC5177794 DOI: 10.1016/j.biopsych.2016.03.2104] [Citation(s) in RCA: 186] [Impact Index Per Article: 26.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/27/2015] [Revised: 03/21/2016] [Accepted: 03/25/2016] [Indexed: 02/08/2023]
Abstract
In light of the clinical evidence implicating dopamine in schizophrenia and the prominent hypotheses put forth regarding alterations in dopaminergic transmission in this disease, molecular imaging has been used to examine multiple aspects of the dopaminergic system. We review the imaging methods used and compare the findings across the different molecular targets. Findings have converged to suggest early dysregulation in the striatum, especially in the rostral caudate, manifesting as excess synthesis and release. Recent data showed deficit extending to most cortical regions and even to other extrastriatal subcortical regions not previously considered to be "hypodopaminergic" in schizophrenia. These findings yield a new topography for the dopaminergic dysregulation in schizophrenia. We discuss the dopaminergic innervation within the individual projection fields to provide a topographical map of this dual dysregulation and explore potential cellular and circuit-based mechanisms for brain region-dependent alterations in dopaminergic parameters. This refined knowledge is essential to better guide translational studies and efforts in early drug development.
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Affiliation(s)
- Jodi J. Weinstein
- Columbia University Department of Psychiatry, New York, NY,New York State Psychiatric Institute Division of Translational Imaging,Corresponding author: Jodi Weinstein, New York State Psychiatric Institute, 1051 Riverside Drive, Unit 31, New York, New York 10032, +1-646-774-8123,
| | - Muhammad O. Chohan
- New York State Psychiatric Institute Division of Integrative Neuroscience
| | - Mark Slifstein
- Columbia University Department of Psychiatry, New York, NY,New York State Psychiatric Institute Division of Translational Imaging
| | - Lawrence S. Kegeles
- Columbia University Department of Psychiatry, New York, NY,New York State Psychiatric Institute Division of Translational Imaging
| | - Holly Moore
- Columbia University Department of Psychiatry, New York, NY,New York State Psychiatric Institute Division of Integrative Neuroscience
| | - Anissa Abi-Dargham
- Columbia University Department of Psychiatry, New York, NY,New York State Psychiatric Institute Division of Translational Imaging
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24
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Goto Y, Lee YA, Yamaguchi Y, Jas E. Biological mechanisms underlying evolutionary origins of psychotic and mood disorders. Neurosci Res 2016; 111:13-24. [PMID: 27230505 DOI: 10.1016/j.neures.2016.04.007] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2015] [Revised: 04/14/2016] [Accepted: 04/22/2016] [Indexed: 02/07/2023]
Abstract
Psychotic and mood disorders are brain dysfunctions that are caused by gene environment interactions. Although these disorders are disadvantageous and involve behavioral phenotypes that decrease the reproductive success of afflicted individuals in the modern human society, the prevalence of these disorders have remained constant in the population. Here, we propose several biological mechanisms by which the genes associated with psychotic and mood disorders could be selected for in specific environmental conditions that provide evolutionary bases for explanations of when, why, and where these disorders emerged and have been maintained in humans. We discuss the evolutionary origins of psychotic and mood disorders with specific focuses on the roles of dopamine and serotonin in the conditions of social competitiveness/hierarchy and maternal care and other potential mechanisms, such as social network homophily and symbiosis.
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Affiliation(s)
- Yukiori Goto
- Cognition and Learning Section, Department of Cognitive Science, Primate Research Institute, Kyoto University, Inuyama, Aichi, 484-8506, Japan.
| | - Young-A Lee
- Department of Food Science & Nutrition, Catholic University of Daegu, Gyeongsan, Gyeongbuk, 712-702, Republic of Korea
| | - Yoshie Yamaguchi
- Cognition and Learning Section, Department of Cognitive Science, Primate Research Institute, Kyoto University, Inuyama, Aichi, 484-8506, Japan
| | - Emanuel Jas
- Graduate School of Natural Sciences, Utrecht University, Princetonplein 5, 3584 CC, Utrecht, The Netherlands
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25
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Abstract
The glutamate and dopamine hypotheses are leading theories of the pathoaetiology of schizophrenia. Both were initially based on indirect evidence from pharmacological studies supported by post-mortem findings, but have since been substantially advanced by new lines of evidence from in vivo imaging studies. This review provides an update on the latest findings on dopamine and glutamate abnormalities in schizophrenia, focusing on in vivo neuroimaging studies in patients and clinical high-risk groups, and considers their implications for understanding the biology and treatment of schizophrenia. These findings have refined both the dopamine and glutamate hypotheses, enabling greater anatomical and functional specificity, and have been complemented by preclinical evidence showing how the risk factors for schizophrenia impact on the dopamine and glutamate systems. The implications of this new evidence for understanding the development and treatment of schizophrenia are considered, and the gaps in current knowledge highlighted. Finally, the evidence for an integrated model of the interactions between the glutamate and dopamine systems is reviewed, and future directions discussed.
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Affiliation(s)
- Oliver Howes
- Psychiatric Imaging, MRC Clinical Sciences Centre, Hammersmith Hospital, London, UK Institute of Psychiatry, King's College London, London, UK
| | - Rob McCutcheon
- Psychiatric Imaging, MRC Clinical Sciences Centre, Hammersmith Hospital, London, UK Institute of Psychiatry, King's College London, London, UK
| | - James Stone
- Psychiatric Imaging, MRC Clinical Sciences Centre, Hammersmith Hospital, London, UK Institute of Psychiatry, King's College London, London, UK
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26
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Wu X, Cai H, Ge R, Li L, Jia Z. Recent progress of imaging agents for Parkinson's disease. Curr Neuropharmacol 2014; 12:551-63. [PMID: 25977680 PMCID: PMC4428027 DOI: 10.2174/1570159x13666141204221238] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2014] [Revised: 11/22/2014] [Accepted: 12/02/2014] [Indexed: 02/05/2023] Open
Abstract
Parkinson's disease (PD) is a common progressive, neurodegenerative brain disease that is promoted by mitochondrial dysfunction, oxidative stress, protein aggregation and proteasome dysfunction in the brain. Compared with computer tomography (CT) or magnetic resonance imaging (MRI), non-invasive nuclear radiopharmaceuticals have great significance for the early diagnosis of PD due to their high sensitivity and specificity in atypical and preclinical cases. Based on the development of coordination chemistry and chelator design, radionuclides may be delivered to lesions by attaching to PD-related transporters and receptors, such as dopamine, serotonin, and others. In this review, we comprehensively detailed the current achievements in radionuclide imaging in Parkinson's disease.
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Affiliation(s)
- Xiaoai Wu
- Department of Nuclear Medicine, West China Hospital of Sichuan University, Chengdu, P.R. China
| | - Huawei Cai
- Department of Nuclear Medicine, West China Hospital of Sichuan University, Chengdu, P.R. China
| | - Ran Ge
- Department of Nuclear Medicine, Fujian Medical University Union Hospital, Fuzhou, P.R. China
| | - Lin Li
- Department of Nuclear Medicine, West China Hospital of Sichuan University, Chengdu, P.R. China
| | - Zhiyun Jia
- Department of Nuclear Medicine, West China Hospital of Sichuan University, Chengdu, P.R. China
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27
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Simpson EH, Winiger V, Biezonski DK, Haq I, Kandel ER, Kellendonk C. Selective overexpression of dopamine D3 receptors in the striatum disrupts motivation but not cognition. Biol Psychiatry 2014; 76:823-31. [PMID: 24387821 PMCID: PMC4047204 DOI: 10.1016/j.biopsych.2013.11.023] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/06/2013] [Revised: 11/01/2013] [Accepted: 11/18/2013] [Indexed: 01/24/2023]
Abstract
BACKGROUND Evidence indicating an increase in dopamine D2 receptor (D2R) density and occupancy in patients with schizophrenia comes from positron emission tomography studies using ligands that bind both D2Rs and dopamine D3 receptors (D3Rs), questioning the role of D3Rs in the pathophysiology of the disease. Dopamine D3 receptor positron emission tomography ligands have recently been developed and antagonists with preferential affinity for D3R versus D2R are undergoing clinical evaluation. To determine if an increase in D3Rs in the striatum could produce phenotypes relevant to schizophrenia, we generated a transgenic model of striatal D3R overexpression. METHODS A bi-transgenic system was used to generate mice with increased D3Rs selectively in the striatum. Mice with overexpression of D3R were subjected to an extensive battery of behavioral tests, including several relevant to schizophrenia. Ligand binding and quantitative reverse transcription polymerase chain reaction methods were used to quantify the effect of D3R overexpression on dopamine D1 receptors (D1Rs) in the striatum. RESULTS Mice with overexpression of D3R show no abnormalities in basic behavioral functions or cognitive tests but do display a deficit in incentive motivation. This was associated with a reduction in striatal D1R ligand binding, driven by a downregulation at the level of transcription. Both motivation and D1R expression were rescued by switching off the transgene in adulthood. CONCLUSIONS Overexpression of D3Rs in the striatum of mice does not elicit cognitive deficits but disrupts motivation, suggesting that changes in D3Rs may be involved in the negative symptoms of schizophrenia. These data imply that it will be important to evaluate the effects of D3R antagonists on motivational symptoms, which are not improved by currently available antipsychotic medications.
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28
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Thompson JL, Rosell DR, Slifstein M, Girgis RR, Xu X, Ehrlich Y, Kegeles LS, Hazlett EA, Abi-Dargham A, Siever LJ. Prefrontal dopamine D1 receptors and working memory in schizotypal personality disorder: a PET study with [¹¹C]NNC112. Psychopharmacology (Berl) 2014; 231:4231-40. [PMID: 24781514 PMCID: PMC4194223 DOI: 10.1007/s00213-014-3566-6] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/02/2013] [Accepted: 03/31/2014] [Indexed: 10/25/2022]
Abstract
RATIONALE Schizotypal personality disorder (SPD) is associated with working memory (WM) impairments that are similar to those observed in schizophrenia. Imaging studies have suggested that schizophrenia is associated with alterations in dopamine D1 receptor availability in the prefrontal cortex (PFC) that may be related to the WM impairments that characterize this disorder. OBJECTIVES The aim of this study was to characterize prefrontal D1 receptor availability and its relation to WM performance in SPD. METHODS We used positron emission tomography (PET) and the radiotracer [(11)C]NNC112 with 18 unmedicated SPD and 21 healthy control participants; as an index of D1 receptor availability, binding potential (BP) measures (BPF, BPND, and BPP) were calculated for prefrontal and striatal subregions. To assess WM, SPD participants completed the 2-back and Paced Auditory Serial Addition Test (PASAT). RESULTS There were no significant group differences in PFC BP. BPF and BPP in the medial PFC were significantly negatively related to PASAT performance (r s = -0.551, p = .022 and r s = -0.488, p = .047, respectively), but BP was not related to 2-back performance. CONCLUSIONS In contrast to what has been found in schizophrenia, SPD was not associated with significant alterations in prefrontal D1 receptor availability. Similar to previous schizophrenia findings, however, higher prefrontal D1 receptor availability was associated with poorer WM performance (as measured by the PASAT) in SPD. These findings suggest that schizophrenia and SPD may share a common pathophysiological feature related to prefrontal dopamine functioning that contributes to WM dysfunction, but that in SPD, alterations in D1 may occur only in a subset of individuals and/or to an extent that is minor relative to what occurs in schizophrenia.
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Affiliation(s)
- Judy L. Thompson
- Department of Psychiatry, Columbia University College of Physicians and
Surgeons, New York, NY, 10032
| | - Daniel R. Rosell
- Department of Psychiatry, Mount Sinai School of Medicine, New York, NY,
10029,James J. Peters Veterans Affairs Medical Center, Bronx, NY, 10468
| | - Mark Slifstein
- Department of Psychiatry, Columbia University College of Physicians and
Surgeons, New York, NY, 10032
| | - Ragy R. Girgis
- Department of Psychiatry, Columbia University College of Physicians and
Surgeons, New York, NY, 10032
| | - Xiaoyan Xu
- Department of Psychiatry, Columbia University College of Physicians and
Surgeons, New York, NY, 10032
| | - Yosefa Ehrlich
- Department of Psychiatry, Mount Sinai School of Medicine, New York, NY,
10029,James J. Peters Veterans Affairs Medical Center, Bronx, NY, 10468
| | - Lawrence S. Kegeles
- Department of Psychiatry, Columbia University College of Physicians and
Surgeons, New York, NY, 10032,Department of Radiology, Columbia University College of Physicians and
Surgeons, New York, NY, 10032
| | - Erin A. Hazlett
- Department of Psychiatry, Mount Sinai School of Medicine, New York, NY,
10029,James J. Peters Veterans Affairs Medical Center, Bronx, NY, 10468
| | - Anissa Abi-Dargham
- Department of Psychiatry, Columbia University College of Physicians and
Surgeons, New York, NY, 10032,Department of Radiology, Columbia University College of Physicians and
Surgeons, New York, NY, 10032
| | - Larry J. Siever
- Department of Psychiatry, Mount Sinai School of Medicine, New York, NY,
10029,James J. Peters Veterans Affairs Medical Center, Bronx, NY, 10468
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29
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Brunelin J, Fecteau S, Suaud-Chagny MF. Abnormal striatal dopamine transmission in schizophrenia. Curr Med Chem 2014; 20:397-404. [PMID: 23157632 PMCID: PMC3866953 DOI: 10.2174/0929867311320030011] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2012] [Revised: 09/05/2012] [Accepted: 09/26/2012] [Indexed: 11/23/2022]
Abstract
Despite numerous revisions and reformulations, dopamine (DA) hypothesis of schizophrenia remains a pivotal neurochemical hypothesis of this illness. The aim of this review is to expose and discuss findings from positron emission tomography (PET) or single-photon-emission computed tomography (SPECT) studies investigating DA function in the striatum of medicated, drug-naïve or drug-free patients with schizophrenia and in individuals at risk compared with healthy volunteers.
DA function was studied at several levels: i) at a presynaptic level where neuroimaging studies investigating DOPA uptake capacity clearly show an increase of DA synthesis in patients with schizophrenia; ii) at a synaptic level where neuroimaging studies investigating dopamine transporter availability (DAT) does not bring any evidence of dysfunction; iii) and finally, neuroimaging studies investigating DA receptor density show a mild increase of D2 receptor density in basic condition and, an hyperreactivity of DA system in dynamic condition.
These results are discussed regarding laterality, sub-regions of striatum and implications for the at-risk population. Striatal DA abnormalities are now clearly demonstrated in patients with schizophrenia and at risk population and could constitute an endophenotype of schizophrenia. Subtle sub-clinical striatal DA abnormalities in at risk population could be a biomarker of transition from a vulnerability state to the expression of frank psychosis.
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Affiliation(s)
- Jerome Brunelin
- Université de Lyon, Université Lyon 1, F-69003, Lyon, France.
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30
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Takahashi H. PET neuroimaging of extrastriatal dopamine receptors and prefrontal cortex functions. ACTA ACUST UNITED AC 2013; 107:503-9. [PMID: 23851135 DOI: 10.1016/j.jphysparis.2013.07.001] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2013] [Revised: 06/27/2013] [Accepted: 07/01/2013] [Indexed: 12/12/2022]
Abstract
The role of prefrontal dopamine D1 receptors in prefrontal cortex (PFC) functions, including working memory, is widely investigated. However, human (healthy volunteers and schizophrenia patients) positron emission tomography (PET) studies about the relationship between prefrontal D1 receptors and PFC functions are somewhat inconsistent. We argued that several factors including an inverted U-shaped relationship between prefrontal D1 receptors and PFC functions might be responsible for these inconsistencies. In contrast to D1 receptors, relatively less attention has been paid to the role of D2 receptors in PFC functions. Several animal and human pharmacological studies have reported that the systemic administration of D2 receptor agonist/antagonist modulates PFC functions, although those studies do not tell us which region(s) is responsible for the effect. Furthermore, while prefrontal D1 receptors are primarily involved in working memory, other PFC functions such as set-shifting seem to be differentially modulated by dopamine. PET studies of extrastriatal D2 receptors including ours suggested that orchestration of prefrontal dopamine transmission and hippocampal dopamine transmission might be necessary for a broad range of normal PFC functions. In order to understand the complex effects of dopamine signaling on PFC functions, measuring a single index related to basic dopamine tone is not sufficient. For a better understanding of the meanings of PET indices related to neurotransmitters, comprehensive information (presynaptic, postsynaptic, and beyond receptor signaling) will be required. Still, an interdisciplinary approach combining molecular imaging techniques with cognitive neuroscience and clinical psychiatry will provide new perspectives for understanding the neurobiology of neuropsychiatric disorders and their innovative drug developments.
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Affiliation(s)
- Hidehiko Takahashi
- Department of Psychiatry, Kyoto University Graduate School of Medicine, 54 Shogoin-Kawara-cho, Sakyo-ku, Kyoto 606-8507, Japan.
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31
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In vivo binding of the dopamine-1 receptor PET tracers [¹¹C]NNC112 and [¹¹C]SCH23390: a comparison study in individuals with schizophrenia. Psychopharmacology (Berl) 2013; 228:167-74. [PMID: 23460265 DOI: 10.1007/s00213-013-3026-8] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/13/2012] [Accepted: 02/03/2013] [Indexed: 10/27/2022]
Abstract
RATIONALE A deficit in dopamine-1 (D1) receptor function in the prefrontal cortex is suggested to play a role in the cognitive dysfunction observed in patients with schizophrenia. However, the results from positron emission tomography imaging studies of D1 receptor levels in individuals with schizophrenia are mixed. OBJECTIVES The aim of this investigation was to determine whether the in vivo characteristics of the different D1 receptor tracers used in previous reports, [(11)C]SCH23390 and [(11)C]NNC112, may have contributed to these discrepancies reported in the literature. METHODS Eight patients with schizophrenia and 12 healthy control subjects were scanned with both [(11)C]SCH23390 and [(11)C]NNC112. RESULTS [(11)C]SCH23390 and [(11)C]NNC112 binding potentials in both patients and control subjects were compared and no tracer by diagnosis interactions were observed. CONCLUSIONS The results of this study suggest that differences in the binding of [(11)C]SCH23390 and [(11)C]NNC112 observed in previous studies are not due to differences in the in vivo behavior of these tracers.
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32
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Chana G, Bousman CA, Money TT, Gibbons A, Gillett P, Dean B, Everall IP. Biomarker investigations related to pathophysiological pathways in schizophrenia and psychosis. Front Cell Neurosci 2013; 7:95. [PMID: 23805071 PMCID: PMC3693064 DOI: 10.3389/fncel.2013.00095] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2013] [Accepted: 06/03/2013] [Indexed: 12/28/2022] Open
Abstract
Post-mortem brain investigations of schizophrenia have generated swathes of data in the last few decades implicating candidate genes and protein. However, the relation of these findings to peripheral biomarker indicators and symptomatology remain to be elucidated. While biomarkers for disease do not have to be involved with underlying pathophysiology and may be largely indicative of diagnosis or prognosis, the ideal may be a biomarker that is involved in underlying disease processes and which is therefore more likely to change with progression of the illness as well as potentially being more responsive to treatment. One of the main difficulties in conducting biomarker investigations for major psychiatric disorders is the relative inconsistency in clinical diagnoses between disorders such as bipolar and schizophrenia. This has led some researchers to investigate biomarkers associated with core symptoms of these disorders, such as psychosis. The aim of this review is to evaluate the contribution of post-mortem brain investigations to elucidating the pathophysiology pathways involved in schizophrenia and psychosis, with an emphasis on major neurotransmitter systems that have been implicated. This data will then be compared to functional neuroimaging findings as well as findings from blood based gene expression investigations in schizophrenia in order to highlight the relative overlap in pathological processes between these different modalities used to elucidate pathogenesis of schizophrenia. In addition we will cover some recent and exciting findings demonstrating microRNA (miRNA) dysregulation in both the blood and the brain in patients with schizophrenia. These changes are pertinent to the topic due to their known role in post-transcriptional modification of gene expression with the potential to contribute or underlie gene expression changes observed in schizophrenia. Finally, we will discuss how post-mortem studies may aid future biomarker investigations.
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Affiliation(s)
- Gursharan Chana
- Department of Psychiatry, Melbourne Brain Centre, The University of Melbourne Parkville, VIC, Australia
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33
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Catts VS, Fung SJ, Long LE, Joshi D, Vercammen A, Allen KM, Fillman SG, Rothmond DA, Sinclair D, Tiwari Y, Tsai SY, Weickert TW, Shannon Weickert C. Rethinking schizophrenia in the context of normal neurodevelopment. Front Cell Neurosci 2013; 7:60. [PMID: 23720610 PMCID: PMC3654207 DOI: 10.3389/fncel.2013.00060] [Citation(s) in RCA: 144] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2013] [Accepted: 04/16/2013] [Indexed: 01/11/2023] Open
Abstract
The schizophrenia brain is differentiated from the normal brain by subtle changes, with significant overlap in measures between normal and disease states. For the past 25 years, schizophrenia has increasingly been considered a neurodevelopmental disorder. This frame of reference challenges biological researchers to consider how pathological changes identified in adult brain tissue can be accounted for by aberrant developmental processes occurring during fetal, childhood, or adolescent periods. To place schizophrenia neuropathology in a neurodevelopmental context requires solid, scrutinized evidence of changes occurring during normal development of the human brain, particularly in the cortex; however, too often data on normative developmental change are selectively referenced. This paper focuses on the development of the prefrontal cortex and charts major molecular, cellular, and behavioral events on a similar time line. We first consider the time at which human cognitive abilities such as selective attention, working memory, and inhibitory control mature, emphasizing that attainment of full adult potential is a process requiring decades. We review the timing of neurogenesis, neuronal migration, white matter changes (myelination), and synapse development. We consider how molecular changes in neurotransmitter signaling pathways are altered throughout life and how they may be concomitant with cellular and cognitive changes. We end with a consideration of how the response to drugs of abuse changes with age. We conclude that the concepts around the timing of cortical neuronal migration, interneuron maturation, and synaptic regression in humans may need revision and include greater emphasis on the protracted and dynamic changes occurring in adolescence. Updating our current understanding of post-natal neurodevelopment should aid researchers in interpreting gray matter changes and derailed neurodevelopmental processes that could underlie emergence of psychosis.
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Affiliation(s)
- Vibeke S. Catts
- Schizophrenia Research Laboratory, Schizophrenia Research InstituteSydney, NSW, Australia
- Neuroscience Research AustraliaSydney, NSW, Australia
- School of Psychiatry, University of New South WalesSydney, NSW, Australia
| | - Samantha J. Fung
- Schizophrenia Research Laboratory, Schizophrenia Research InstituteSydney, NSW, Australia
- Neuroscience Research AustraliaSydney, NSW, Australia
- School of Psychiatry, University of New South WalesSydney, NSW, Australia
| | - Leonora E. Long
- Schizophrenia Research Laboratory, Schizophrenia Research InstituteSydney, NSW, Australia
- Neuroscience Research AustraliaSydney, NSW, Australia
- School of Medical Sciences, University of New South WalesSydney, NSW, Australia
| | - Dipesh Joshi
- Schizophrenia Research Laboratory, Schizophrenia Research InstituteSydney, NSW, Australia
- Neuroscience Research AustraliaSydney, NSW, Australia
- School of Psychiatry, University of New South WalesSydney, NSW, Australia
| | - Ans Vercammen
- Schizophrenia Research Laboratory, Schizophrenia Research InstituteSydney, NSW, Australia
- Neuroscience Research AustraliaSydney, NSW, Australia
- School of Psychiatry, University of New South WalesSydney, NSW, Australia
- School of Psychology, Australian Catholic UniversitySydney, NSW, Australia
| | - Katherine M. Allen
- Schizophrenia Research Laboratory, Schizophrenia Research InstituteSydney, NSW, Australia
- Neuroscience Research AustraliaSydney, NSW, Australia
- School of Psychiatry, University of New South WalesSydney, NSW, Australia
| | - Stu G. Fillman
- Schizophrenia Research Laboratory, Schizophrenia Research InstituteSydney, NSW, Australia
- Neuroscience Research AustraliaSydney, NSW, Australia
- School of Psychiatry, University of New South WalesSydney, NSW, Australia
| | - Debora A. Rothmond
- Schizophrenia Research Laboratory, Schizophrenia Research InstituteSydney, NSW, Australia
- Neuroscience Research AustraliaSydney, NSW, Australia
| | - Duncan Sinclair
- Schizophrenia Research Laboratory, Schizophrenia Research InstituteSydney, NSW, Australia
- Neuroscience Research AustraliaSydney, NSW, Australia
- School of Psychiatry, University of New South WalesSydney, NSW, Australia
| | - Yash Tiwari
- Schizophrenia Research Laboratory, Schizophrenia Research InstituteSydney, NSW, Australia
- Neuroscience Research AustraliaSydney, NSW, Australia
- School of Medical Sciences, University of New South WalesSydney, NSW, Australia
| | - Shan-Yuan Tsai
- Schizophrenia Research Laboratory, Schizophrenia Research InstituteSydney, NSW, Australia
- Neuroscience Research AustraliaSydney, NSW, Australia
- School of Psychiatry, University of New South WalesSydney, NSW, Australia
| | - Thomas W. Weickert
- Schizophrenia Research Laboratory, Schizophrenia Research InstituteSydney, NSW, Australia
- Neuroscience Research AustraliaSydney, NSW, Australia
- School of Psychiatry, University of New South WalesSydney, NSW, Australia
| | - Cynthia Shannon Weickert
- Schizophrenia Research Laboratory, Schizophrenia Research InstituteSydney, NSW, Australia
- Neuroscience Research AustraliaSydney, NSW, Australia
- School of Psychiatry, University of New South WalesSydney, NSW, Australia
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34
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Urigüen L, Gil-Pisa I, Munarriz-Cuezva E, Berrocoso E, Pascau J, Soto-Montenegro ML, Gutiérrez-Adán A, Pintado B, Madrigal JLM, Castro E, Sánchez-Blázquez P, Ortega JE, Guerrero MJ, Ferrer-Alcon M, García-Sevilla JA, Micó JA, Desco M, Leza JC, Pazos Á, Garzón J, Meana JJ. Behavioral, neurochemical and morphological changes induced by the overexpression of munc18-1a in brain of mice: relevance to schizophrenia. Transl Psychiatry 2013; 3:e221. [PMID: 23340504 PMCID: PMC3566728 DOI: 10.1038/tp.2012.149] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
Overexpression of the mammalian homolog of the unc-18 gene (munc18-1) has been described in the brain of subjects with schizophrenia. Munc18-1 protein is involved in membrane fusion processes, exocytosis and neurotransmitter release. A transgenic mouse strain that overexpresses the protein isoform munc18-1a in the brain was characterized. This animal displays several schizophrenia-related behaviors, supersensitivity to hallucinogenic drugs and deficits in prepulse inhibition that reverse after antipsychotic treatment. Relevant brain areas (that is, cortex and striatum) exhibit reduced expression of dopamine D(1) receptors and dopamine transporters together with enhanced amphetamine-induced in vivo dopamine release. Magnetic resonance imaging demonstrates decreased gray matter volume in the transgenic animal. In conclusion, the mouse overexpressing brain munc18-1a represents a new valid animal model that resembles functional and structural abnormalities in patients with schizophrenia. The animal could provide valuable insights into phenotypic aspects of this psychiatric disorder.
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Affiliation(s)
- L Urigüen
- Centro de Investigación Biomédica en Red de Salud Mental CIBERSAM, Spain,Department of Pharmacology, University of the Basque Country UPV/EHU Leioa, Bizkaia, Spain,BioCruces Health Research Institute, Bizkaia, Spain
| | - I Gil-Pisa
- Centro de Investigación Biomédica en Red de Salud Mental CIBERSAM, Spain,Department of Pharmacology, University of the Basque Country UPV/EHU Leioa, Bizkaia, Spain
| | - E Munarriz-Cuezva
- Centro de Investigación Biomédica en Red de Salud Mental CIBERSAM, Spain,Department of Pharmacology, University of the Basque Country UPV/EHU Leioa, Bizkaia, Spain
| | - E Berrocoso
- Centro de Investigación Biomédica en Red de Salud Mental CIBERSAM, Spain,Department of Neuroscience, University of Cádiz, Cádiz, Spain
| | - J Pascau
- Centro de Investigación Biomédica en Red de Salud Mental CIBERSAM, Spain,Department of Experimental Medicine and Surgery, General Hospital Gregorio Marañón, Madrid, Spain
| | - M L Soto-Montenegro
- Centro de Investigación Biomédica en Red de Salud Mental CIBERSAM, Spain,Department of Experimental Medicine and Surgery, General Hospital Gregorio Marañón, Madrid, Spain
| | | | - B Pintado
- Department of Animal Reproduction, INIA, Madrid, Spain
| | - J L M Madrigal
- Centro de Investigación Biomédica en Red de Salud Mental CIBERSAM, Spain,Department of Pharmacology, Faculty of Medicine, Complutense University, Madrid, Spain
| | - E Castro
- Centro de Investigación Biomédica en Red de Salud Mental CIBERSAM, Spain,Department of Physiology and Pharmacology, University of Cantabria, Institute of Biomedicine and Biotechnology of Cantabria IBBTEC), Santander, Spain
| | - P Sánchez-Blázquez
- Centro de Investigación Biomédica en Red de Salud Mental CIBERSAM, Spain,Cajal Institute, CSIC, Madrid, Spain
| | - J E Ortega
- Centro de Investigación Biomédica en Red de Salud Mental CIBERSAM, Spain,Department of Pharmacology, University of the Basque Country UPV/EHU Leioa, Bizkaia, Spain,BioCruces Health Research Institute, Bizkaia, Spain
| | | | | | - J A García-Sevilla
- Neuropharmacology Laboratory, IUNICS, University of Balearic Islands, Palma de Mallorca and Redes Temáticas de Investigación Cooperativa en Salud, Red de Trastornos Adictivos (RETICS-RTA), Spain
| | - J A Micó
- Centro de Investigación Biomédica en Red de Salud Mental CIBERSAM, Spain,Department of Neuroscience, University of Cádiz, Cádiz, Spain
| | - M Desco
- Centro de Investigación Biomédica en Red de Salud Mental CIBERSAM, Spain,Department of Experimental Medicine and Surgery, General Hospital Gregorio Marañón, Madrid, Spain,Department of Bioengineering and Aerospace Engineering, Carlos III University, Madrid, Spain
| | - J C Leza
- Centro de Investigación Biomédica en Red de Salud Mental CIBERSAM, Spain,Department of Pharmacology, Faculty of Medicine, Complutense University, Madrid, Spain
| | - Á Pazos
- Centro de Investigación Biomédica en Red de Salud Mental CIBERSAM, Spain,Department of Physiology and Pharmacology, University of Cantabria, Institute of Biomedicine and Biotechnology of Cantabria IBBTEC), Santander, Spain
| | - J Garzón
- Centro de Investigación Biomédica en Red de Salud Mental CIBERSAM, Spain,Cajal Institute, CSIC, Madrid, Spain
| | - J J Meana
- Centro de Investigación Biomédica en Red de Salud Mental CIBERSAM, Spain,Department of Pharmacology, University of the Basque Country UPV/EHU Leioa, Bizkaia, Spain,BioCruces Health Research Institute, Bizkaia, Spain,Department of Pharmacology, University of the Basque Country (UPV/EHU), Leioa, Bizkaia 48940, Spain. E-mail:
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35
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Horiguchi M, Hannaway KE, Adelekun AE, Huang M, Jayathilake K, Meltzer HY. D(1) receptor agonists reverse the subchronic phencyclidine (PCP)-induced novel object recognition (NOR) deficit in female rats. Behav Brain Res 2012; 238:36-43. [PMID: 23018127 DOI: 10.1016/j.bbr.2012.09.030] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2012] [Revised: 09/14/2012] [Accepted: 09/18/2012] [Indexed: 12/26/2022]
Abstract
Development of dopamine (DA) D(1) receptor agonists is a priority to improve cognitive impairment in schizophrenia (CIS). This study examined the dose-response relationship of the selective D(1) agonist, SKF38393 (0.5-40 mg/kg), to reverse the deficit in novel object recognition (NOR), an analog of declarative memory in man, produced by subchronic phencyclidine (PCP), an N-methyl-D-aspartate (NMDA) receptor non-competitive antagonist, and the ability of the D(1) antagonists, SCH23390 (0.05 mg/kg) and SKF83566 (0.15 mg/kg), to impair NOR in normal Long-Evans female rats. We also examined the ability of tandospirone, a serotonin (5-HT)(1A) receptor partial agonist, and LY341495, a mGluR2/3 receptor antagonist, to potentiate or block the effects of SKF38393 on NOR, respectively. SKF38393 reversed the persistent NOR deficit produced by subchronic PCP; the dose-response curve for SKF38393 was an inverted U-shape, with the peak effect at 6 mg/kg. SKF83566 and SCH23390 impaired NOR in normal rats. Co-administration of sub-effective doses of SKF38393 (0.25 mg/kg) and tandospirone (0.2 mg/kg) improved the PCP-induced NOR deficit, while LY341495 (1 mg/kg) blocked the ameliorating effect of SKF38393 (6 mg/kg), respectively. These data provide the first evidence that the reversal of the PCP-induced NOR deficit by D(1) agonism has an inverted U-shaped dose-response curve and that 5-HT(1A) and mGluR2/3 receptor signalling facilitates the efficacy of D(1) agonism to improve these deficits. These data suggest that although D(1) agonists may be useful to improve CIS, these agents, particularly higher doses, may also worsen cognitive function in some patients, because of an inverted U-shaped dose response curve.
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Affiliation(s)
- Masakuni Horiguchi
- Division of Psychopharmacology, Vanderbilt University Medical Center, Nashville, TN 37212, USA
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Takahashi H, Yamada M, Suhara T. Functional significance of central D1 receptors in cognition: beyond working memory. J Cereb Blood Flow Metab 2012; 32:1248-58. [PMID: 22234338 PMCID: PMC3390810 DOI: 10.1038/jcbfm.2011.194] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The role of dopamine D1 receptors in prefrontal cortex function, including working memory, is well acknowledged. However, relatively little is known about their role in other cognitive or emotional functions. We measured both D1 and D2 receptors in the brain using positron emission tomography in healthy subjects, with the aim of elucidating how regional D1 and D2 receptors are differentially involved in cognitive and emotional functions beyond working memory. We found an inverted U-shaped relation between prefrontal D1 receptor availability and Wisconsin Card Sorting Test performance, indicating that too little or too much D1 receptor stimulation impairs working memory or set shifting. In addition, variability of D1 receptor availability in the amygdala and striatum was related to individual differences in emotional responses and decision-making processes, respectively. These observations suggest that the variability of available D1 receptors might be associated with individual differences in brain functions that require phasic dopamine release. An interdisciplinary approach combining molecular imaging of dopamine neurotransmission with cognitive neuroscience and clinical psychiatry will provide new perspectives for understanding the neurobiology of neuropsychiatric disorders such as schizophrenia, addiction and Parkinson's disease, as well as novel therapeutics for cognitive impairments observed in them.
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Affiliation(s)
- Hidehiko Takahashi
- Department of Psychiatry, Kyoto University Graduate School of Medicine, Kyoto, Japan.
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Abstract
The results of imaging studies have played an important role in the formulation of hypotheses regarding the etiology of psychosis and schizophrenia, as well as in our understanding of the mechanisms of action of antipsychotics. Since this volume is primarily directed to molecular aspects of psychosis and antipsychotics, only the results of molecular imaging techniques addressing these topics will be discussed here.One of the most consistent findings of molecular imaging studies in schizophrenia is an increased uptake of DOPA in the striatum, which may be interpreted as an increased synthesis of L-DOPA. Also, several studies reported an increased release of dopamine induced by amphetamine in schizophrenia patients. These findings played an important role in reformulating the dopamine hypothesis of schizophrenia. To study the roles of the neurotransmitters γ-aminobutyric acid (GABA) and glutamate in schizophrenia, SPECT as well as MR spectroscopy have been used. The results of preliminary SPECT studies are consistent with the hypothesis of NMDA receptor dysfunction in schizophrenia. Regarding the GABA deficit hypothesis of schizophrenia, imaging results are inconsistent. No changes in serotonin transporters were demonstrated in imaging studies in schizophrenia, but studies of several serotonin receptors showed conflicting results. The lack of selective radiotracers for muscarinic receptors may have hampered examination of this system in schizophrenia as well as its role in the induction of side effects of antipsychotics. Interestingly, preliminary molecular imaging studies on the cannabinoid-1 receptor and on neuroinflammatory processes in schizophrenia have recently been published. Finally, a substantial number of PET/SPECT studies have examined the occupancy of receptors by antipsychotics and an increasing number of studies is now focusing on the effects of these drugs using techniques like spectroscopy and pharmacological MRI.
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Remington G, Agid O, Foussias G. Schizophrenia as a disorder of too little dopamine: implications for symptoms and treatment. Expert Rev Neurother 2011; 11:589-607. [PMID: 21469931 DOI: 10.1586/ern.10.191] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Antipsychotics represent the first effective therapy for schizophrenia, with their benefits linked to dopamine D2 blockade. Schizophrenia was soon identified as a hyperdopaminergic disorder, and antipsychotics proved to be reasonably effective in controlling positive symptoms. However, over the years, schizophrenia has been reconceptualized more broadly, now defined as a heterogeneous disorder with multiple symptom domains. Negative and cognitive features, not particularly responsive to antipsychotic therapy, have taken on increased importance--current thinking suggests that these domains predate the onset of positive symptoms and are more closely tied to functional outcome. That they are better understood in the context of decreased dopamine activity suggests that schizophrenia may fundamentally represent a hypodopaminergic disorder. This shift in thinking has important theoretical implications from the standpoint of etiology and pathophysiology, but also clinically in terms of treatment and drug development.
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Hirvonen J, Hietala J. Dysfunctional brain networks and genetic risk for schizophrenia: specific neurotransmitter systems. CNS Neurosci Ther 2010; 17:89-96. [PMID: 21199447 DOI: 10.1111/j.1755-5949.2010.00223.x] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Multiple neurotransmitter circuits are disturbed in schizophrenia, and the dopamine hypothesis of schizophrenia prevails as the hypothesis with most empirical support. On the other hand, schizophrenia is highly heritable with a pattern consistent with both common and rare allelic variants and gene × environment interaction. Advances in the field of neuroimaging have expanded our knowledge of intermediate phenotypes, the neurobiological processes that convey the risk from the genes to the complex phenotype. In this article, we review the recent and continuously accumulating evidence from in vivo imaging studies aiming at characterizing neurochemical intermediate phenotypes of schizophrenia. Dopaminergic alterations in schizophrenia are shared by individuals at genetic risk who do not express the illness, suggesting a "dopamine hypothesis of schizophrenia vulnerability." This hypothesis has the potential to help us better understand the dopaminergic dysfunction in the context of the complex pathophysiological process leading to schizophrenia. In the future, neurotransmitter imaging studies should investigate the gene × environment interaction in schizophrenia, and try to identify neurobiological correlates of heightened sensitivity to environmental stressors (e.g., cannabis, childhood trauma, and other psychosocial stress) in genetically vulnerable individuals.
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Affiliation(s)
- Jussi Hirvonen
- Department of Radiology, Turku University Hospital and University of Turku, Turku, Finland.
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