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Bossi S, Pizzamiglio L, Paoletti P. Excitatory GluN1/GluN3A glycine receptors (eGlyRs) in brain signaling. Trends Neurosci 2023:S0166-2236(23)00127-3. [PMID: 37248111 DOI: 10.1016/j.tins.2023.05.002] [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: 03/17/2023] [Revised: 04/28/2023] [Accepted: 05/04/2023] [Indexed: 05/31/2023]
Abstract
GluN3A is a glycine-binding subunit belonging to the NMDA receptor (NMDAR) family that can assemble with GluN1 subunits to form unconventional NMDARs insensitive to glutamate and activated by glycine only. The existence of such excitatory glycine receptors (eGlyRs) in the central nervous system (CNS) has long remained elusive. Recently, eGlyRs have been identified in specific brain regions, where they represent a novel neuronal signaling modality by which extracellular glycine tunes neuronal excitability, circuit function, and behavior. In this review, we summarize the emerging knowledge regarding these underappreciated receptors. The existence of eGlyRs reshapes current understanding of NMDAR diversity and of glycinergic signaling, previously thought to be primarily inhibitory. Given that GluN3A expression is concentrated in brain regions regulating emotional responses, eGlyRs are potential new targets of therapeutic interest in neuropsychiatry.
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Affiliation(s)
- Simon Bossi
- Institut de Biologie de l'École Normale Supérieure (IBENS), Ecole Normale Supérieure, Université PSL, CNRS, INSERM, F-75005 Paris, France
| | - Lara Pizzamiglio
- Institut de Biologie de l'École Normale Supérieure (IBENS), Ecole Normale Supérieure, Université PSL, CNRS, INSERM, F-75005 Paris, France
| | - Pierre Paoletti
- Institut de Biologie de l'École Normale Supérieure (IBENS), Ecole Normale Supérieure, Université PSL, CNRS, INSERM, F-75005 Paris, France.
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2
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Brandão-Teles C, Smith BJ, Carregari VC. PTMs: A Missing Piece for Schizophrenia Studies. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2022; 1382:119-127. [DOI: 10.1007/978-3-031-05460-0_9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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3
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Grubisha MJ, Sweet RA, MacDonald ML. Investigating Post-translational Modifications in Neuropsychiatric Disease: The Next Frontier in Human Post-mortem Brain Research. Front Mol Neurosci 2021; 14:689495. [PMID: 34335181 PMCID: PMC8322442 DOI: 10.3389/fnmol.2021.689495] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2021] [Accepted: 06/18/2021] [Indexed: 12/27/2022] Open
Abstract
Gene expression and translation have been extensively studied in human post-mortem brain tissue from subjects with psychiatric disease. Post-translational modifications (PTMs) have received less attention despite their implication by unbiased genetic studies and importance in regulating neuronal and circuit function. Here we review the rationale for studying PTMs in psychiatric disease, recent findings in human post-mortem tissue, the required controls for these types of studies, and highlight the emerging mass spectrometry approaches transforming this research direction.
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Affiliation(s)
- Melanie J. Grubisha
- Department of Psychiatry, University of Pittsburgh, Pittsburgh, PA, United States
| | - Robert A. Sweet
- Department of Psychiatry, University of Pittsburgh, Pittsburgh, PA, United States
| | - Matthew L. MacDonald
- Department of Psychiatry, University of Pittsburgh, Pittsburgh, PA, United States
- Biomedical Mass Spectrometry Center, University of Pittsburgh, Pittsburgh, PA, United States
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4
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Koizumi H, Hiraga T, Oharomari LK, Hata T, Shima T, Yook JS, Okamoto M, Mouri A, Nabeshima T, Soya H. Preventive role of regular low-intensity exercise during adolescence in schizophrenia model mice with abnormal behaviors. Biochem Biophys Res Commun 2020; 534:610-616. [PMID: 33228965 DOI: 10.1016/j.bbrc.2020.11.032] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2020] [Accepted: 11/09/2020] [Indexed: 10/23/2022]
Abstract
Schizophrenia is probably ascribed to perinatal neurodevelopmental deficits, and its onset might be affected by environmental factors. Hypofrontality with glutamatergic and dopaminergic neuronal dysfunction are known factors, but a way to mitigate abnormalities remains unfound. An early enriched environment such as a wheel running in rodents may contribute to the prevention, but its clinical applicability is very limited. From our studies, low-intensity exercise training (LET) based on physiological indices, such as lactate threshold, easily translates to humans and positively affects the brains. Hence, LET during adolescence may ameliorate abnormalities in neurodevelopment and prevent the development of schizophrenia. In the current study, LET prevented sensitization to phencyclidine (PCP) treatment, impairment of cognition, and affective behavioral abnormalities in an animal model of schizophrenia induced by prenatal PCP treatment. Further, LET increased dopamine turnover and attenuated the impairment of phosphorylation of ERK1/2 after exposure to a novel object in the prenatal PCP-treated mice. These results suggest that LET during adolescence completely improves schizophrenia-like abnormal behaviors associated with improved glutamate uptake and the dopamine-induced ERK1/2 signaling pathway in the PFC.
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Affiliation(s)
- Hikaru Koizumi
- Laboratory of Exercise Biochemistry and Neuroendocrinology, Faculty of Health and Sport Sciences, University of Tsukuba, Tsukuba, 305-8574, Ibaraki, Japan; Department of Sport Neuroscience, Advanced Research Initiative for Human High Performance (ARIHHP), Faculty of Health and Sport Sciences, University of Tsukuba, Tsukuba, 305-8574, Ibaraki, Japan
| | - Taichi Hiraga
- Laboratory of Exercise Biochemistry and Neuroendocrinology, Faculty of Health and Sport Sciences, University of Tsukuba, Tsukuba, 305-8574, Ibaraki, Japan; Department of Sport Neuroscience, Advanced Research Initiative for Human High Performance (ARIHHP), Faculty of Health and Sport Sciences, University of Tsukuba, Tsukuba, 305-8574, Ibaraki, Japan
| | - Leandro K Oharomari
- Laboratory of Exercise Biochemistry and Neuroendocrinology, Faculty of Health and Sport Sciences, University of Tsukuba, Tsukuba, 305-8574, Ibaraki, Japan
| | - Toshiaki Hata
- Laboratory of Exercise Biochemistry and Neuroendocrinology, Faculty of Health and Sport Sciences, University of Tsukuba, Tsukuba, 305-8574, Ibaraki, Japan; Department of Sport Neuroscience, Advanced Research Initiative for Human High Performance (ARIHHP), Faculty of Health and Sport Sciences, University of Tsukuba, Tsukuba, 305-8574, Ibaraki, Japan
| | - Takeru Shima
- Laboratory of Exercise Biochemistry and Neuroendocrinology, Faculty of Health and Sport Sciences, University of Tsukuba, Tsukuba, 305-8574, Ibaraki, Japan
| | - Jang Soo Yook
- Laboratory of Exercise Biochemistry and Neuroendocrinology, Faculty of Health and Sport Sciences, University of Tsukuba, Tsukuba, 305-8574, Ibaraki, Japan
| | - Masahiro Okamoto
- Laboratory of Exercise Biochemistry and Neuroendocrinology, Faculty of Health and Sport Sciences, University of Tsukuba, Tsukuba, 305-8574, Ibaraki, Japan; Department of Sport Neuroscience, Advanced Research Initiative for Human High Performance (ARIHHP), Faculty of Health and Sport Sciences, University of Tsukuba, Tsukuba, 305-8574, Ibaraki, Japan
| | - Akihiro Mouri
- Advanced Diagnostic System Research Laboratory, Fujita Health University, Graduate School of Health Sciences, Toyoake, 470-1192, Aichi, Japan; Department of Regulatory Science for Evaluation and Development of Pharmaceuticals and Devices, Fujita Health University, Graduate School of Health Sciences, Toyoake, 470-1192, Aichi, Japan
| | - Toshitaka Nabeshima
- Advanced Diagnostic System Research Laboratory, Fujita Health University, Graduate School of Health Sciences, Toyoake, 470-1192, Aichi, Japan
| | - Hideaki Soya
- Laboratory of Exercise Biochemistry and Neuroendocrinology, Faculty of Health and Sport Sciences, University of Tsukuba, Tsukuba, 305-8574, Ibaraki, Japan; Department of Sport Neuroscience, Advanced Research Initiative for Human High Performance (ARIHHP), Faculty of Health and Sport Sciences, University of Tsukuba, Tsukuba, 305-8574, Ibaraki, Japan.
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5
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Mouri A, Lee HJ, Mamiya T, Aoyama Y, Matsumoto Y, Kubota H, Huang WJ, Chiou LC, Nabeshima T. Hispidulin attenuates the social withdrawal in isolated disrupted-in-schizophrenia-1 mutant and chronic phencyclidine-treated mice. Br J Pharmacol 2020; 177:3210-3224. [PMID: 32133633 DOI: 10.1111/bph.15043] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2019] [Revised: 12/16/2019] [Accepted: 02/13/2020] [Indexed: 12/11/2022] Open
Abstract
BACKGROUND AND PURPOSE Hispidulin is a flavonoid isolated from Clerodendrum inerme that was found to inhibit intractable motor tics. Previously, we found that hispidulin attenuates hyperlocomotion and the disrupted prepulse inhibition induced by methamphetamine and N-methyl-d-aspartate (NMDA) receptor antagonists, two phenotypes of schizophrenia resembling positive symptoms. Hispidulin can inhibit COMT, a dopamine-metabolizing enzyme in the prefrontal cortex (PFC) that is important for social interaction. Here, we investigated whether hispidulin would affect social withdrawal, one of the negative symptoms of schizophrenia. EXPERIMENTAL APPROACH We examined whether acute administration of hispidulin would attenuate social withdrawal in two mice models, juvenile isolated disrupted-in-schizophrenia-1 mutant (mutDISC1) mice and chronic phencyclidine (PCP)-treated naïve mice. KEY RESULTS In chronic PCP-treated mice, hispidulin (10 mg·kg-1 , i.p.) attenuated social withdrawal similar to that observed with dopamine D1 receptor antagonist (SCH-23390, 0.02 mg·kg-1 , i.p.) and was mimicked by the selective COMT inhibitor, OR-486 (10 mg·kg-1 , i.p.). Hispidulin increased extracellular dopamine levels in the PFC of chronic PCP-treated mice. In isolated mutDISC1 mice, hispidulin also reversed social withdrawal. In both models, intra-PFC microinjection of a D1 agonist (SKF-81297: 10 nmol/mouse/bilateral) reversed the impairment of Ser897 phosphorylation at the GluN1 subunit of NMDA receptors, suggesting the association between GluN1 Ser897 -phosphorylation and D1 activation in the PFC exits in both models. CONCLUSIONS AND IMPLICATIONS Hispidulin attenuated social withdrawal by activating D1 receptors indirectly through elevated dopamine levels in the PFC by COMT inhibition. This nature of hispidulin suggests that it a potential novel therapeutic candidate for the treatment of negative symptoms in schizophrenia.
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Affiliation(s)
- Akihiro Mouri
- Advanced Diagnostic System Research Laboratory, Fujita Health University, Graduate School of Health Sciences, Toyoake, Japan.,Department of Regulatory Science for Evaluation and Development of Pharmaceuticals and Devices, Fujita Health University, Graduate School of Health Sciences, Toyoake, Japan.,Japanese Drug Organization of Appropriate Use and Research, Nagoya, Japan
| | - Hsin-Jung Lee
- Department of Pharmacology, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Takayoshi Mamiya
- Department of Chemical Pharmacology, Faculty of Pharmacy, Meijo University, Nagoya, Japan
| | - Yuki Aoyama
- Department of Chemical Pharmacology, Faculty of Pharmacy, Meijo University, Nagoya, Japan
| | - Yurie Matsumoto
- Department of Chemical Pharmacology, Faculty of Pharmacy, Meijo University, Nagoya, Japan
| | - Hisayoshi Kubota
- Department of Regulatory Science for Evaluation and Development of Pharmaceuticals and Devices, Fujita Health University, Graduate School of Health Sciences, Toyoake, Japan
| | - Wei-Jan Huang
- Graduate Institute of Pharmacognosy, Taipei Medical University, Taipei, Taiwan
| | - Lih-Chu Chiou
- Department of Pharmacology, College of Medicine, National Taiwan University, Taipei, Taiwan.,Graduate Institute of Brain and Mind Sciences, College of Medicine, National Taiwan University, Taipei, Taiwan.,Graduate Institute of Acupuncture Science, China Medical University, Taichung, Taiwan
| | - Toshitaka Nabeshima
- Advanced Diagnostic System Research Laboratory, Fujita Health University, Graduate School of Health Sciences, Toyoake, Japan.,Department of Chemical Pharmacology, Faculty of Pharmacy, Meijo University, Nagoya, Japan.,Japanese Drug Organization of Appropriate Use and Research, Nagoya, Japan
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6
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Kumar A, Pareek V, Singh HN, Faiq MA, Narayan RK, Raza K, Kumar P. Altered Expression of a Unique Set of Genes Reveals Complex Etiology of Schizophrenia. Front Psychiatry 2019; 10:906. [PMID: 31920755 PMCID: PMC6920214 DOI: 10.3389/fpsyt.2019.00906] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/06/2019] [Accepted: 11/15/2019] [Indexed: 01/26/2023] Open
Abstract
Background: The etiology of schizophrenia is extensively debated, and multiple factors have been contended to be involved. A panoramic view of the contributing factors in a genome-wide study can be an effective strategy to provide a comprehensive understanding of its causality. Materials and Methods: GSE53987 dataset downloaded from GEO-database, which comprised mRNA expression data of post-mortem brain tissue across three regions from control (C) and age-matched subjects (T) of schizophrenia (N = Hippocampus [HIP]: C-15, T-18, Prefrontal cortex [PFC]: C-15, T-19, Associative striatum [STR]: C-18, T-18). Bio-conductor-affy-package used to compute mRNA expression, and further t-test applied to investigate differential gene expression. The analysis of the derived genes performed using the PANTHER Classification System and NCBI database. Further, a protein interactome analysis of the derived gene set was performed using STRING v10 database (https://string-db.org/) Results: A set of 40 genes showed significantly altered (p < 0.01) expression across all three brain regions. The analyses unraveled genes implicated in biological processes and events, and molecular pathways relating basic neuronal functions. Conclusions: The aberrant expression of genes maintaining basic cell machinery explains compromised neuronal processing in SCZ.
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Affiliation(s)
- Ashutosh Kumar
- Department of Anatomy, All India Institute of Medical Sciences (AIIMS), Patna, India
- Department of Anatomy, All India Institute of Medical Sciences (AIIMS), New Delhi, India
- Etiologically Elusive Disorders Research Network (EEDRN), New Delhi, India
| | - Vikas Pareek
- Etiologically Elusive Disorders Research Network (EEDRN), New Delhi, India
- Computational Neuroscience and Neuroimaging Division, National Brain Research Centre (NBRC), Manesar, India
| | - Himanshu N. Singh
- Etiologically Elusive Disorders Research Network (EEDRN), New Delhi, India
- TAGC—Theories and Approaches of Genomic Complexity, Aix Marseille University, Inserm U1090, Marseille, France
| | - Muneeb A. Faiq
- Etiologically Elusive Disorders Research Network (EEDRN), New Delhi, India
- Neuroimaging and Visual Science Laboratory, New York University (NYU) Langone Health Centre, NYU Robert I. Grossman School of Medicine, New York, NY, United States
| | - Ravi K. Narayan
- Department of Anatomy, All India Institute of Medical Sciences (AIIMS), Patna, India
- Etiologically Elusive Disorders Research Network (EEDRN), New Delhi, India
| | - Khursheed Raza
- Department of Anatomy, All India Institute of Medical Sciences (AIIMS), New Delhi, India
- Etiologically Elusive Disorders Research Network (EEDRN), New Delhi, India
| | - Pavan Kumar
- Etiologically Elusive Disorders Research Network (EEDRN), New Delhi, India
- Developmental Neurogenetics Lab, Department of Pediatrics, Medical University of South Carolina, Charleston, SC, United States
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7
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Synaptic Plasticity Shapes Brain Connectivity: Implications for Network Topology. Int J Mol Sci 2019; 20:ijms20246193. [PMID: 31817968 PMCID: PMC6940892 DOI: 10.3390/ijms20246193] [Citation(s) in RCA: 58] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2019] [Revised: 12/02/2019] [Accepted: 12/06/2019] [Indexed: 12/13/2022] Open
Abstract
Studies of brain network connectivity improved understanding on brain changes and adaptation in response to different pathologies. Synaptic plasticity, the ability of neurons to modify their connections, is involved in brain network remodeling following different types of brain damage (e.g., vascular, neurodegenerative, inflammatory). Although synaptic plasticity mechanisms have been extensively elucidated, how neural plasticity can shape network organization is far from being completely understood. Similarities existing between synaptic plasticity and principles governing brain network organization could be helpful to define brain network properties and reorganization profiles after damage. In this review, we discuss how different forms of synaptic plasticity, including homeostatic and anti-homeostatic mechanisms, could be directly involved in generating specific brain network characteristics. We propose that long-term potentiation could represent the neurophysiological basis for the formation of highly connected nodes (hubs). Conversely, homeostatic plasticity may contribute to stabilize network activity preventing poor and excessive connectivity in the peripheral nodes. In addition, synaptic plasticity dysfunction may drive brain network disruption in neuropsychiatric conditions such as Alzheimer's disease and schizophrenia. Optimal network architecture, characterized by efficient information processing and resilience, and reorganization after damage strictly depend on the balance between these forms of plasticity.
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8
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Tong J, Huang J, Luo X, Chen S, Cui Y, An H, Xiu M, Tan S, Wang Z, Yuan Y, Zhang J, Yang F, Li CSR, Hong LE, Tan Y. Elevated serum anti-NMDA receptor antibody levels in first-episode patients with schizophrenia. Brain Behav Immun 2019; 81:213-219. [PMID: 31201848 PMCID: PMC6754783 DOI: 10.1016/j.bbi.2019.06.017] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/30/2018] [Revised: 06/12/2019] [Accepted: 06/12/2019] [Indexed: 02/06/2023] Open
Abstract
Accumulating evidence has shown that N-methyl-D-aspartate (NMDA) glutamate receptors (NMDAR) are implicated in the pathophysiology of neurological and psychiatric disorders, and that patients with NMDAR antibody encephalitis develop psychopathological symptoms. Therefore, we hypothesized that NMDAR antibodies play a key role in the etiology of schizophrenia. In this study, we enrolled 110 first-episode patients with schizophrenia (FEP) and 50 healthy controls (HC). Cognitive function and psychopathology were assessed using the Measurement and Treatment Research to Improve Cognition in Schizophrenia (MATRICS) Consensus Cognitive Battery (MCCB) and Positive and Negative Syndrome Scale (PANSS), respectively. NMDAR antibody levels were measured using enzyme-linked immunosorbent assay. Our results showed that FEP with schizophrenia exhibited cognitive deficits in all domains of the MCCB and had elevated levels of serum anti-NMDAR antibody compared with the healthy controls (9.2 ± 3.5 vs. 7.3 ± 2.9 ng/ml, t = 3.10, p = 0.002). Furthermore, serum antibody levels were positively correlated with PANSS positive, negative and total score, and inversely correlated with performances of verbal learning and memory, working memory, speed of processing and MCCB total score in the patient group. These results indicate that elevated levels of NMDAR antibody may play a role in the pathogenesis of schizophrenia, leading to NMDAR dysfunction, thereby inducing symptoms of psychosis and cognitive impairment. Therefore, NMDAR antibodies may serve as a biomarker and provide a new avenue for treatment of schizophrenia.
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Affiliation(s)
- Jinghui Tong
- Peking University HuiLongGuan Clinical Medical School, Beijing HuiLongGuan Hospital, Beijing, P. R. China
| | - Junchao Huang
- Peking University HuiLongGuan Clinical Medical School, Beijing HuiLongGuan Hospital, Beijing, P. R. China
| | - Xingguang Luo
- Department of Psychiatry, Yale University School of Medicine, New Haven, CT, USA
| | - Song Chen
- Peking University HuiLongGuan Clinical Medical School, Beijing HuiLongGuan Hospital, Beijing, P. R. China
| | - Yimin Cui
- Department of Pharmacy, Peking University First Hospital, Beijing, P.R. China
| | - Huimei An
- Peking University HuiLongGuan Clinical Medical School, Beijing HuiLongGuan Hospital, Beijing, P. R. China
| | - Meihong Xiu
- Peking University HuiLongGuan Clinical Medical School, Beijing HuiLongGuan Hospital, Beijing, P. R. China
| | - Shuping Tan
- Peking University HuiLongGuan Clinical Medical School, Beijing HuiLongGuan Hospital, Beijing, P. R. China
| | - Zhiren Wang
- Peking University HuiLongGuan Clinical Medical School, Beijing HuiLongGuan Hospital, Beijing, P. R. China
| | - Ying Yuan
- School of Foreign Languages and Literature, Tianjin University, Tianjin, P. R. China
| | - Jianxin Zhang
- Peking University HuiLongGuan Clinical Medical School, Beijing HuiLongGuan Hospital, Beijing, P. R. China
| | - Fude Yang
- Peking University HuiLongGuan Clinical Medical School, Beijing HuiLongGuan Hospital, Beijing, P. R. China
| | - Chiang-Shan R. Li
- Department of Psychiatry, Yale University School of Medicine, New Haven, CT, USA
| | - L. Elliot Hong
- Maryland Psychiatric Research Center, Department of Psychiatry, University of Maryland School of Medicine, Baltimore, USA
| | - Yunlong Tan
- Peking University HuiLongGuan Clinical Medical School, Beijing HuiLongGuan Hospital, Beijing, PR China.
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9
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The role of N-methyl-d-aspartate receptors and metabotropic glutamate receptor 5 in the prepulse inhibition paradigms for studying schizophrenia: pharmacology, neurodevelopment, and genetics. Behav Pharmacol 2018; 29:13-27. [DOI: 10.1097/fbp.0000000000000352] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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10
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Forsyth JK, Bachman P, Mathalon DH, Roach BJ, Ye E, Asarnow RF. Effects of Augmenting N-Methyl-D-Aspartate Receptor Signaling on Working Memory and Experience-Dependent Plasticity in Schizophrenia: An Exploratory Study Using Acute d-cycloserine. Schizophr Bull 2017; 43:1123-1133. [PMID: 28338977 PMCID: PMC5581900 DOI: 10.1093/schbul/sbw193] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
Cognitive deficits in schizophrenia have been hypothesized to reflect N-methyl-D-aspartate receptor (NMDAR) dysfunction. However, the mechanisms through which the NMDAR contributes to individual cognitive functions differ. To explore how NMDAR signaling relates to specific cognitive deficits in schizophrenia, we tested the effects of enhancing NMDAR signaling on working memory and experience-dependent plasticity using d-cycloserine (DCS). Plasticity was assessed using an EEG paradigm that utilizes high-frequency visual stimulation (HFvS) to induce neural potentiation, and 2 learning tasks, the information integration (IIT) and weather prediction (WPT) tasks. Working memory was assessed using an N-back task. Forty-five schizophrenia patients were randomized to receive a single 100 mg DCS dose (SZ-DCS; n = 24) or placebo (SZ-PLC; n = 21) in a double-blind, between-groups design. Testing occurred on a single day after placebo or DCS administration; baseline values were not obtained. DCS did not affect plasticity, as indicated by similar neural potentiation, and similar IIT and WPT learning between groups. However, among patients who successfully engaged in the working memory task (ie, performed above chance), SZ-DCS (n = 17) showed superior 2-back performance compared to SZ-PLC (n = 16). Interestingly, SZ-DCS also showed larger pre-HFvS neural responses during the LTP task. Notably, this pattern of DCS effects is the opposite of those found in our prior study of healthy adults. Results are consistent with target engagement of the NMDAR by DCS, but suggest that NMDAR signaling was not translated into synaptic plasticity changes in schizophrenia. Results highlight the importance of considering how distinct NMDAR-associated processes contribute to individual cognitive deficits in schizophrenia.
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Affiliation(s)
- Jennifer K Forsyth
- Department of Psychology, University of California, Los Angeles, Los Angeles, CA
| | - Peter Bachman
- Department of Psychiatry, University of Pittsburgh, Pittsburgh, PA
| | - Daniel H Mathalon
- Department of Psychiatry and Biomedical Sciences, University of California, San Francisco, San Francisco, CA;,San Francisco Veterans Affairs Medical Center, San Francisco, CA
| | - Brian J Roach
- San Francisco Veterans Affairs Medical Center, San Francisco, CA
| | - Elissa Ye
- Department of Psychology, University of California, Los Angeles, Los Angeles, CA
| | - Robert F Asarnow
- Department of Psychology, University of California, Los Angeles, Los Angeles, CA;,Department of Psychiatry and Biobehavioral Sciences, University of California, Los Angeles, Los Angeles, CA,To whom correspondence should be addressed; Department of Psychology, University of California, Los Angeles, 760 Westwood Plaza, Los Angeles, CA 90095; tel: (310) 825-0394, fax: (310) 206-4446, e-mail:
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11
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Forsyth JK, Lewis DA. Mapping the Consequences of Impaired Synaptic Plasticity in Schizophrenia through Development: An Integrative Model for Diverse Clinical Features. Trends Cogn Sci 2017; 21:760-778. [PMID: 28754595 DOI: 10.1016/j.tics.2017.06.006] [Citation(s) in RCA: 95] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2017] [Revised: 05/13/2017] [Accepted: 06/09/2017] [Indexed: 01/19/2023]
Abstract
Schizophrenia is associated with alterations in sensory, motor, and cognitive functions that emerge before psychosis onset; identifying pathogenic processes that can account for this multi-faceted phenotype remains a challenge. Accumulating evidence suggests that synaptic plasticity is impaired in schizophrenia. Given the role of synaptic plasticity in learning, memory, and neural circuit maturation, impaired plasticity may underlie many features of the schizophrenia syndrome. Here, we summarize the neurobiology of synaptic plasticity, review evidence that plasticity is impaired in schizophrenia, and explore a framework in which impaired synaptic plasticity interacts with brain maturation to yield the emergence of sensory, motor, cognitive, and psychotic features at different times during development in schizophrenia. Key gaps in the literature and future directions for testing this framework are discussed.
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Affiliation(s)
- Jennifer K Forsyth
- Department of Psychology, University of California at Los Angeles, Los Angeles, CA, USA; Department of Psychiatry and Biobehavioral Sciences, University of California at Los Angeles, Los Angeles, CA, USA.
| | - David A Lewis
- Department of Psychiatry, University of Pittsburgh, Pittsburgh, PA, USA
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12
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Porcelli S, Balzarro B, Lee SJ, Han C, Patkar AA, Pae CU, Serretti A. PDE7B, NMBR and EPM2A Variants and Schizophrenia: A Case-Control and Pharmacogenetics Study. Neuropsychobiology 2017; 73:160-8. [PMID: 27092952 DOI: 10.1159/000445295] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/28/2015] [Accepted: 03/02/2016] [Indexed: 11/19/2022]
Abstract
BACKGROUND We investigated phosphodiesterase 7B (PDE7B), neuromedin B receptor (NMBR) and epilepsy progressive myoclonus type 2A (EPM2A) genes in schizophrenia (SCZ). To the best of our knowledge, these genes have been poorly investigated in studies of SCZ. METHODS Five hundred and seventy-three SCZ inpatients of Korean ethnicity and 560 healthy controls were genotyped for 2 PDE7B, 3 NMBR and 3 EPM2A polymorphisms. Differences in the allelic and genetic frequencies among healthy subjects and patients were calculated using the x03C7;2 statistics. Repeated-measure ANOVA was used to test possible influences of single-nucleotide polymorphisms on treatment efficacy. In case of positive findings, clinical and demographic variables were added as covariates, in order to investigate possible stratixFB01;cation bias. RESULTS The rs2717 and rs6926279 within the NMBR gene and rs702304 and rs2235481 within the EPM2A gene were associated with SCZ liability. rs1415744 was also associated with Positive and Negative Symptom Scale negative clinical improvement. The results remained the same after inclusion of the covariates and were partially confirmed in the allelic and haplotype analyses. CONCLUSION Our preliminary findings suggest a possible role of NMBR and EPM2A genes in SCZ susceptibility and, for the second one, also in antipsychotic pharmacogenetics. Nonetheless, further research is needed to conxFB01;rm our findings.
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Affiliation(s)
- Stefano Porcelli
- Institute of Psychiatry, Department of Biomedical and Neuromotor Sciences, University of Bologna, Bologna, Italy
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13
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Knox LT, Jing Y, Bawazier-Edgecombe J, Collie ND, Zhang H, Liu P. Effects of withdrawal from repeated phencyclidine administration on behavioural function and brain arginine metabolism in rats. Pharmacol Biochem Behav 2016; 153:45-59. [PMID: 27986516 DOI: 10.1016/j.pbb.2016.12.006] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/10/2016] [Revised: 07/20/2016] [Accepted: 12/12/2016] [Indexed: 12/13/2022]
Abstract
Phencyclidine (PCP) induces behavioural changes in humans and laboratory animals that resemble positive and negative symptoms, and cognitive impairments in schizophrenia. It has been shown repeated treatment of PCP leading to persistent symptoms even after the drug discontinuation, and there is a growing body of evidence implicating altered arginine metabolism in the pathogenesis of schizophrenia. The present study investigated the effects of withdrawal from repeated daily injection of PCP (2mg/kg) for 12 consecutive days on animals'behavioural performance and arginine metabolism in the hippocampus and prefrontal cortex in male young adult rats. Repeated PCP treatment reduced spontaneous alternations in the Y-maze and exploratory and locomotor activities in the open field under the condition of a washout period of 24h, but not 4days. Interestingly, the PCP treated rats also displayed spatial working memory deficits when tested 8-10days after withdrawal from PCP and showed altered levels of arginase activities and eight out of ten l-arginine metabolites in neurochemical- and region-specific manner. Cluster analyses showed altered relationships among l-arginine and its three main metabolites as a function of withdrawal from repeated PCP treatment in a duration-specific manner. Multiple regression analysis revealed significant neurochemical-behavioural correlations. Collectively, the results suggest both the residual and long-term effects of withdrawal from repeated PCP treatment on behavioural function and brain arginine metabolism. These findings demonstrate, for the first time, the influence of the withdrawal duration on animals' behaviour and brain arginine metabolism.
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Affiliation(s)
- Logan T Knox
- Department of Anatomy, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand; Brain Health Research Centre, University of Otago, Dunedin, New Zealand
| | - Yu Jing
- Department of Anatomy, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand; Brain Health Research Centre, University of Otago, Dunedin, New Zealand
| | - Jamal Bawazier-Edgecombe
- Department of Anatomy, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand; Brain Health Research Centre, University of Otago, Dunedin, New Zealand
| | - Nicola D Collie
- Department of Anatomy, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand; Brain Health Research Centre, University of Otago, Dunedin, New Zealand
| | - Hu Zhang
- School of Pharmacy, University of Otago, Dunedin, New Zealand; Brain Health Research Centre, University of Otago, Dunedin, New Zealand
| | - Ping Liu
- Department of Anatomy, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand; Brain Health Research Centre, University of Otago, Dunedin, New Zealand.
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Murphy E, Benítez-Burraco A. Bridging the Gap between Genes and Language Deficits in Schizophrenia: An Oscillopathic Approach. Front Hum Neurosci 2016; 10:422. [PMID: 27601987 PMCID: PMC4993770 DOI: 10.3389/fnhum.2016.00422] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2016] [Accepted: 08/08/2016] [Indexed: 12/11/2022] Open
Abstract
Schizophrenia is characterized by marked language deficits, but it is not clear how these deficits arise from the alteration of genes related to the disease. The goal of this paper is to aid the bridging of the gap between genes and schizophrenia and, ultimately, give support to the view that the abnormal presentation of language in this condition is heavily rooted in the evolutionary processes that brought about modern language. To that end we will focus on how the schizophrenic brain processes language and, particularly, on its distinctive oscillatory profile during language processing. Additionally, we will show that candidate genes for schizophrenia are overrepresented among the set of genes that are believed to be important for the evolution of the human faculty of language. These genes crucially include (and are related to) genes involved in brain rhythmicity. We will claim that this translational effort and the links we uncover may help develop an understanding of language evolution, along with the etiology of schizophrenia, its clinical/linguistic profile, and its high prevalence among modern populations.
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Affiliation(s)
- Elliot Murphy
- Division of Psychology and Language Sciences, University College London London, UK
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Catts VS, Lai YL, Weickert CS, Weickert TW, Catts SV. A quantitative review of the postmortem evidence for decreased cortical N-methyl-d-aspartate receptor expression levels in schizophrenia: How can we link molecular abnormalities to mismatch negativity deficits? Biol Psychol 2016; 116:57-67. [DOI: 10.1016/j.biopsycho.2015.10.013] [Citation(s) in RCA: 73] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2015] [Revised: 10/19/2015] [Accepted: 10/30/2015] [Indexed: 02/06/2023]
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Kobayashi Y, Kulikova SP, Shibato J, Rakwal R, Satoh H, Pinault D, Masuo Y. DNA microarray unravels rapid changes in transcriptome of MK-801 treated rat brain. World J Biol Chem 2015; 6:389-408. [PMID: 26629322 PMCID: PMC4657125 DOI: 10.4331/wjbc.v6.i4.389] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/26/2014] [Revised: 01/20/2015] [Accepted: 08/31/2015] [Indexed: 02/05/2023] Open
Abstract
AIM: To investigate the impact of MK-801 on gene expression patterns genome wide in rat brain regions.
METHODS: Rats were treated with an intraperitoneal injection of MK-801 [0.08 (low-dose) and 0.16 (high-dose) mg/kg] or NaCl (vehicle control). In a first series of experiment, the frontoparietal electrocorticogram was recorded 15 min before and 60 min after injection. In a second series of experiments, the whole brain of each animal was rapidly removed at 40 min post-injection, and different regions were separated: amygdala, cerebral cortex, hippocampus, hypothalamus, midbrain and ventral striatum on ice followed by DNA microarray (4 × 44 K whole rat genome chip) analysis.
RESULTS: Spectral analysis revealed that a single systemic injection of MK-801 significantly and selectively augmented the power of baseline gamma frequency (30-80 Hz) oscillations in the frontoparietal electroencephalogram. DNA microarray analysis showed the largest number (up- and down- regulations) of gene expressions in the cerebral cortex (378), midbrain (376), hippocampus (375), ventral striatum (353), amygdala (301), and hypothalamus (201) under low-dose (0.08 mg/kg) of MK-801. Under high-dose (0.16 mg/kg), ventral striatum (811) showed the largest number of gene expression changes. Gene expression changes were functionally categorized to reveal expression of genes and function varies with each brain region.
CONCLUSION: Acute MK-801 treatment increases synchrony of baseline gamma oscillations, and causes very early changes in gene expressions in six individual rat brain regions, a first report.
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Postsynaptic density levels of the NMDA receptor NR1 subunit and PSD-95 protein in prefrontal cortex from people with schizophrenia. NPJ SCHIZOPHRENIA 2015; 1:15037. [PMID: 27336043 PMCID: PMC4849460 DOI: 10.1038/npjschz.2015.37] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/27/2015] [Revised: 09/14/2015] [Accepted: 09/18/2015] [Indexed: 12/17/2022]
Abstract
Background: There is converging evidence of involvement of N-methyl-d-aspartate (NMDA) receptor hypofunction in the pathophysiology of schizophrenia. Our group recently identified a decrease in total NR1 mRNA and protein expression in the dorsolateral prefrontal cortex in a case-control study of individuals with schizophrenia (n=37/group). The NR1 subunit is critical to NMDA receptor function at the postsynaptic density, a cellular structure rich in the scaffolding protein, PSD-95. The extent to which the NMDA receptor NR1 subunit is altered at the site of action, in the postsynaptic density, is not clear. Aims: To extend our previous results by measuring levels of NR1 and PSD-95 protein in postsynaptic density-enriched fractions of prefrontal cortex from the same individuals in the case-control study noted above. Methods: Postsynaptic density-enriched fractions were isolated from fresh-frozen prefrontal cortex (BA10) and subjected to western blot analysis for NR1 and PSD-95. Results: We found a 20% decrease in NR1 protein (t(66)=−2.874, P=0.006) and a 30% decrease in PSD-95 protein (t(63)=−2.668, P=0.010) in postsynaptic density-enriched fractions from individuals with schizophrenia relative to unaffected controls. Conclusions: Individuals with schizophrenia have less NR1 protein, and therefore potentially fewer functional NMDA receptors, at the postsynaptic density. The associated decrease in PSD-95 protein at the postsynaptic density suggests that not only are glutamate receptors compromised in individuals with schizophrenia, but the overall spine architecture and downstream signaling supported by PSD-95 may also be deficient.
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Sallam HS, Tumurbaatar B, Zhang WR, Tuvdendorj D, Chandalia M, Tempia F, Laezza F, Taglialatela G, Abate N. Peripheral adipose tissue insulin resistance alters lipid composition and function of hippocampal synapses. J Neurochem 2015; 133:125-33. [PMID: 25640170 DOI: 10.1111/jnc.13043] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2014] [Revised: 12/19/2014] [Accepted: 01/14/2015] [Indexed: 12/13/2022]
Abstract
Compelling evidence indicates that type 2 diabetes mellitus, insulin resistance (IR), and metabolic syndrome are often accompanied by cognitive impairment. However, the mechanistic link between these metabolic abnormalities and CNS dysfunction requires further investigations. Here, we evaluated whether adipose tissue IR and related metabolic alterations resulted in CNS changes by studying synapse lipid composition and function in the adipocyte-specific ecto-nucleotide pyrophosphate phosphodiesterase over-expressing transgenic (AtENPP1-Tg) mouse, a model characterized by white adipocyte IR, systemic IR, and ectopic fat deposition. When fed a high-fat diet, AtENPP1-Tg mice recapitulate essential features of the human metabolic syndrome, making them an ideal model to characterize peripherally induced CNS deficits. Using a combination of gas chromatography and western blot analysis, we found evidence of altered lipid composition, including decreased phospholipids and increased triglycerides (TG) and free fatty acid in hippocampal synaptosomes isolated from high-fat diet-fed AtENPP1-Tg mice. These changes were associated with impaired basal synaptic transmission at the Schaffer collaterals to hippocampal cornu ammonis 1 (CA1) synapses, decreased phosphorylation of the GluN1 glutamate receptor subunit, down-regulation of insulin receptor expression, and up-regulation of the free fatty acid receptor 1.
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Affiliation(s)
- Hanaa S Sallam
- Division of Endocrinology, Department of Internal Medicine, University of Texas Medical Branch, Galveston, Texas, USA
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Effects of long-term treatment with the neuroleptics haloperidol, clozapine and olanzapine on immunoexpression of NMDA receptor subunits NR1, NR2A and NR2B in the rat hippocampus. Pharmacol Rep 2015; 67:965-9. [PMID: 26398392 DOI: 10.1016/j.pharep.2015.01.017] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2014] [Revised: 01/28/2015] [Accepted: 01/30/2015] [Indexed: 12/18/2022]
Abstract
BACKGROUND Antagonists of the N-methyl-d-aspartate receptor (NMDA-R) are associated with symptoms of schizophrenia, leading to the hypothesis that NMDA-R hypofunction leads to the pathogenesis of disease. We evaluated the long-term effect of neuroleptic administration on the NMDA subunits via immunohistochemical analysis. METHODS Rats received olanzapine, clozapine and haloperidol before evaluation of the expression of the NR1, NR2A and NR2B subunit proteins in the hippocampal areas of the brain, via a densytometric analysis of immunoexpression in the rat hippocampus. RESULTS All of the neuroleptics examined caused a decrease in the expression of the NR1 subunit, and thus, one can assume that both olanzapine, clozapine and haloperidol decreased the number of NMDA receptors in the CA1 and CA2 areas of the brain. CONCLUSIONS A decrease in hippocampal glutamatergic signalling after long-term neuroleptic administration may cautiously explain the incomplete effectiveness of these drugs in the therapy of schizophrenia-related cognitive disturbances.
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Boeckx C, Benítez-Burraco A. Globularity and language-readiness: generating new predictions by expanding the set of genes of interest. Front Psychol 2014; 5:1324. [PMID: 25505436 PMCID: PMC4243498 DOI: 10.3389/fpsyg.2014.01324] [Citation(s) in RCA: 54] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2014] [Accepted: 10/31/2014] [Indexed: 12/30/2022] Open
Abstract
This study builds on the hypothesis put forth in Boeckx and Benítez-Burraco (2014), according to which the developmental changes expressed at the levels of brain morphology and neural connectivity that resulted in a more globular braincase in our species were crucial to understand the origins of our language-ready brain. Specifically, this paper explores the links between two well-known 'language-related' genes like FOXP2 and ROBO1 implicated in vocal learning and the initial set of genes of interest put forth in Boeckx and Benítez-Burraco (2014), with RUNX2 as focal point. Relying on the existing literature, we uncover potential molecular links that could be of interest to future experimental inquiries into the biological foundations of language and the testing of our initial hypothesis. Our discussion could also be relevant for clinical linguistics and for the interpretation of results from paleogenomics.
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Affiliation(s)
- Cedric Boeckx
- Catalan Institute for Advanced Studies and Research (ICREA)Barcelona, Spain
- Department of Linguistics, Universitat de BarcelonaBarcelona, Spain
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21
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Funk AJ, Haroutunian V, Meador-Woodruff JH, McCullumsmith RE. Increased G protein-coupled receptor kinase (GRK) expression in the anterior cingulate cortex in schizophrenia. Schizophr Res 2014; 159:130-5. [PMID: 25153362 PMCID: PMC4177355 DOI: 10.1016/j.schres.2014.07.040] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/17/2014] [Revised: 07/18/2014] [Accepted: 07/20/2014] [Indexed: 01/11/2023]
Abstract
BACKGROUND Current pharmacological treatments for schizophrenia target G protein-coupled receptors (GPCRs), including dopamine receptors. Ligand-bound GPCRs are regulated by a family of G protein-coupled receptor kinases (GRKs), members of which uncouple the receptor from heterotrimeric G proteins, desensitize the receptor, and induce receptor internalization via the arrestin family of scaffolding and signaling molecules. GRKs initiate the activation of downstream signaling pathways, can regulate receptors and signaling molecules independent of GPCR phosphorylation, and modulate epigenetic regulators like histone deacetylases (HDACs). We hypothesize that the expression of GRK proteins is altered in schizophrenia, consistent with previous findings of alterations upstream and downstream from this family of molecules that facilitate intracellular signaling processes. METHODS In this study, we measured protein expression via Western blot analysis for GRKs 2, 3, 5, and 6 in the anterior cingulate cortex of patients with schizophrenia (n=36) and a comparison group (n=33). To control for antipsychotic treatment, we measured these same targets in haloperidol-treated vs. untreated rats (n=10 for both). RESULTS We found increased levels of GRK5 in schizophrenia. No changes were detected in GRK protein expression in rats treated with haloperidol decanoate for 9 months. CONCLUSION These data suggest that increased GRK5 expression may contribute to the pathophysiology of schizophrenia via abnormal regulation of the cytoskeleton, endocytosis, signaling, GPCRs, and histone modification.
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Affiliation(s)
- Adam J. Funk
- Department of Psychiatry and Behavioral Neuroscience, University of Cincinnati, CARE 5830, 231 Albert Sabin Way, Cincinnati, OH 45267-0583
| | - Vahram Haroutunian
- Department of Psychiatry, Mount Sinai School of Medicine, One Gustave L. Levy Place, Box 1230, New York, NY 10029
| | - James H. Meador-Woodruff
- Department of Psychiatry and Behavioral Neurobiology, University of Alabama Birmingham, SC 560, 1530 3 Avenue South, Birmingham, AL 35294,Evelyn F. McKnight Brain Institute, University of Alabama Birmingham, Shelby 911, 1530 3 Avenue South, Birmingham, AL 35294
| | - Robert E. McCullumsmith
- Department of Psychiatry and Behavioral Neuroscience, University of Cincinnati, CARE 5830, 231 Albert Sabin Way, Cincinnati, OH 45267-0583
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Effects of acute phencyclidine administration on arginine metabolism in the hippocampus and prefrontal cortex in rats. Neuropharmacology 2014; 81:195-205. [DOI: 10.1016/j.neuropharm.2014.02.004] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2013] [Revised: 01/03/2014] [Accepted: 02/05/2014] [Indexed: 12/19/2022]
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McGuire JL, Hammond JH, Yates SD, Chen D, Haroutunian V, Meador-Woodruff JH, McCullumsmith RE. Altered serine/threonine kinase activity in schizophrenia. Brain Res 2014; 1568:42-54. [PMID: 24780530 DOI: 10.1016/j.brainres.2014.04.029] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2014] [Revised: 04/19/2014] [Accepted: 04/21/2014] [Indexed: 10/25/2022]
Abstract
Converging evidence implicates alterations in multiple signaling pathways in the etiology of schizophrenia. Previously, these studies were limited to the analysis of one or a few phosphoproteins at a time. Here, we use a novel kinase array platform to simultaneously investigate the convergence of multiple signaling cascades implicated in schizophrenia. This technology uses consensus peptide substrates to assess activity levels of a large number (>100) of serine/threonine protein kinases. 19 peptide substrates were differentially phosphorylated (>15% change) in the frontal cortex in schizophrenia. These peptide substrates were examined using Ingenuity Pathway Analysis to group them according to the functions and to identify processes most likely affected in schizophrenia. Pathway analysis placed 14 of the 19 peptides into cellular homeostatic pathways, 10 into pathways governing cytoskeletal organization, and 8 into pathways governing ion homeostasis. These data are the first to simultaneously investigate comprehensive changes in signaling cascades in a severe psychiatric disorder. The examination of kinase activity in signaling pathways may facilitate the identification of novel substrates for drug discovery and the development of safer and more effective pharmacological treatment for schizophrenia.
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Affiliation(s)
- Jennifer L McGuire
- Department of Psychiatry and Behavioral Neuroscience, University of Cincinnati, Cincinnati, OH, USA.
| | - John H Hammond
- Department of Psychiatry and Behavioral Neurobiology, University of Alabama at Birmingham, Birmingham, AL, USA.
| | - Stefani D Yates
- Department of Psychiatry and Behavioral Neurobiology, University of Alabama at Birmingham, Birmingham, AL, USA.
| | - Dongquan Chen
- Division of Preventative Medicine, University of Alabama at Birmingham, Birmingham, AL, USA.
| | - Vahram Haroutunian
- Department of Psychiatry, Mount Sinai School of Medicine, New York, NY, USA.
| | - James H Meador-Woodruff
- Department of Psychiatry and Behavioral Neurobiology, University of Alabama at Birmingham, Birmingham, AL, USA.
| | - Robert E McCullumsmith
- Department of Psychiatry and Behavioral Neuroscience, University of Cincinnati, Cincinnati, OH, USA.
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Effects of chronic electroacupuncture on depression- and anxiety-like behaviors in rats with chronic neuropathic pain. EVIDENCE-BASED COMPLEMENTARY AND ALTERNATIVE MEDICINE 2014; 2014:158987. [PMID: 24795763 PMCID: PMC3984799 DOI: 10.1155/2014/158987] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/15/2014] [Accepted: 02/24/2014] [Indexed: 01/09/2023]
Abstract
Growing evidence indicates that chronic neuropathic pain is frequently accompanied by an array of psychiatric diseases, such as depression and anxiety. Electroacupuncture (EA), as one therapy of traditional Chinese medicine, has displayed potent antidepressant-like effects in numerous clinical studies. The present study was designed to examine the possible effects of EA on the depressive and anxiety disorders induced by neuropathic pain. A classic rat model of neuropathic pain was produced by chronic constriction injury (CCI) of the sciatic nerve. EA was performed on acupoints “Bai-Hui” (GV20) and unilateral “Yang-Ling-Quan” (GB34). The antidepressive and anxiolytic effects of EA treatment were analyzed using the forced swimming test (FST) and the elevated plus maze (EPM) test, respectively. CCI resulted in remarkable depression- and anxiety-like behaviors, whereas the chronic EA treatment significantly improved the behavioral deficits of CCI rats. Moreover, the phosphorylation level of the NMDA receptor type 1 (NR1) subunit was decreased in the hippocampus of CCI rats. Intriguingly, continuous EA treatment effectively blocked this decrease in the levels of pNR1. These results suggested that EA has antidepressive and anxiolytic effects on rats with neuropathic pain and that this might be associated with restoring the phosphorylation of NR1 in the hippocampus.
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McCullumsmith RE, Hammond JH, Shan D, Meador-Woodruff JH. Postmortem brain: an underutilized substrate for studying severe mental illness. Neuropsychopharmacology 2014; 39:65-87. [PMID: 24091486 PMCID: PMC3857666 DOI: 10.1038/npp.2013.239] [Citation(s) in RCA: 81] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/15/2013] [Revised: 07/30/2013] [Accepted: 08/02/2013] [Indexed: 02/08/2023]
Abstract
We propose that postmortem tissue is an underutilized substrate that may be used to translate genetic and/or preclinical studies, particularly for neuropsychiatric illnesses with complex etiologies. Postmortem brain tissues from subjects with schizophrenia have been extensively studied, and thus serve as a useful vehicle for illustrating the challenges associated with this biological substrate. Schizophrenia is likely caused by a combination of genetic risk and environmental factors that combine to create a disease phenotype that is typically not apparent until late adolescence. The complexity of this illness creates challenges for hypothesis testing aimed at understanding the pathophysiology of the illness, as postmortem brain tissues collected from individuals with schizophrenia reflect neuroplastic changes from a lifetime of severe mental illness, as well as treatment with antipsychotic medications. While there are significant challenges with studying postmortem brain, such as the postmortem interval, it confers a translational element that is difficult to recapitulate in animal models. On the other hand, data derived from animal models typically provide specific mechanistic and behavioral measures that cannot be generated using human subjects. Convergence of these two approaches has led to important insights for understanding molecular deficits and their causes in this illness. In this review, we discuss the problem of schizophrenia, review the common challenges related to postmortem studies, discuss the application of biochemical approaches to this substrate, and present examples of postmortem schizophrenia studies that illustrate the role of the postmortem approach for generating important new leads for understanding the pathophysiology of severe mental illness.
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Affiliation(s)
| | - John H Hammond
- Department of Psychiatry and Behavioral Neurobiology, University of Alabama-Birmingham, Birmingham, AL, USA
| | - Dan Shan
- Department of Psychiatry and Behavioral Neurobiology, University of Alabama-Birmingham, Birmingham, AL, USA
| | - James H Meador-Woodruff
- Department of Psychiatry and Behavioral Neurobiology, University of Alabama-Birmingham, Birmingham, AL, USA
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de Bartolomeis A, Latte G, Tomasetti C, Iasevoli F. Glutamatergic postsynaptic density protein dysfunctions in synaptic plasticity and dendritic spines morphology: relevance to schizophrenia and other behavioral disorders pathophysiology, and implications for novel therapeutic approaches. Mol Neurobiol 2013; 49:484-511. [PMID: 23999870 DOI: 10.1007/s12035-013-8534-3] [Citation(s) in RCA: 101] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2013] [Accepted: 08/13/2013] [Indexed: 02/06/2023]
Abstract
Emerging researches point to a relevant role of postsynaptic density (PSD) proteins, such as PSD-95, Homer, Shank, and DISC-1, in the pathophysiology of schizophrenia and autism spectrum disorders. The PSD is a thickness, detectable at electronic microscopy, localized at the postsynaptic membrane of glutamatergic synapses, and made by scaffolding proteins, receptors, and effector proteins; it is considered a structural and functional crossroad where multiple neurotransmitter systems converge, including the dopaminergic, serotonergic, and glutamatergic ones, which are all implicated in the pathophysiology of psychosis. Decreased PSD-95 protein levels have been reported in postmortem brains of schizophrenia patients. Variants of Homer1, a key PSD protein for glutamate signaling, have been associated with schizophrenia symptoms severity and therapeutic response. Mutations in Shank gene have been recognized in autism spectrum disorder patients, as well as reported to be associated to behaviors reminiscent of schizophrenia symptoms when expressed in genetically engineered mice. Here, we provide a critical appraisal of PSD proteins role in the pathophysiology of schizophrenia and autism spectrum disorders. Then, we discuss how antipsychotics may affect PSD proteins in brain regions relevant to psychosis pathophysiology, possibly by controlling synaptic plasticity and dendritic spine rearrangements through the modulation of glutamate-related targets. We finally provide a framework that may explain how PSD proteins might be useful candidates to develop new therapeutic approaches for schizophrenia and related disorders in which there is a need for new biological treatments, especially against some symptom domains, such as negative symptoms, that are poorly affected by current antipsychotics.
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Affiliation(s)
- Andrea de Bartolomeis
- Laboratory of Molecular and Translational Psychiatry, Unit of Treatment Resistant Psychosis, Department of Neuroscience, Reproductive and Odontostomatologic Sciences, Section of Psychiatry, University School of Medicine "Federico II", Via Pansini 5, 80131, Naples, Italy,
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Mouri A, Nagai T, Ibi D, Yamada K. Animal models of schizophrenia for molecular and pharmacological intervention and potential candidate molecules. Neurobiol Dis 2013; 53:61-74. [DOI: 10.1016/j.nbd.2012.10.025] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2012] [Revised: 10/23/2012] [Accepted: 10/28/2012] [Indexed: 12/22/2022] Open
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Abstract
1-42 β-Amyloid (Aβ(1-42)) peptide is a key molecule involved in the development of Alzheimer's disease. Some of its effects are manifested at the neuronal morphological level. These morphological changes involve loss of neurites due to cytoskeleton alterations. However, the mechanism of Aβ(1-42) peptide activation of the neurodegenerative program is still poorly understood. Here, Aβ(1-42) peptide-induced transduction of cellular death signals through the phosphatidylinositol 3-kinase (PI3K)/phosphoinositol-dependent kinase (PDK)/novel protein kinase C (nPKC)/Rac 1 axis is described. Furthermore, pharmacological inhibition of PDK1 and nPKC activities blocks Rac 1 activation and neuronal cell death. Our results provide insights into an unsuspected connection between PDK1, nPKCs and Rac 1 in the same signal-transduction pathway and points out nPKCs and Rac 1 as potential therapeutic targets to block the toxic effects of Aβ(1-42) peptide in neurons.
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Abnormal activity of the MAPK- and cAMP-associated signaling pathways in frontal cortical areas in postmortem brain in schizophrenia. Neuropsychopharmacology 2012; 37:896-905. [PMID: 22048463 PMCID: PMC3280643 DOI: 10.1038/npp.2011.267] [Citation(s) in RCA: 113] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Recent evidence suggests that schizophrenia may result from alterations of integration of signaling mediated by multiple neurotransmitter systems. Abnormalities of associated intracellular signaling pathways may contribute to the pathophysiology of schizophrenia. Proteins and phospho-proteins comprising mitogen activated protein kinase (MAPK) and 3'-5'-cyclic adenosine monophosphate (cAMP)-associated signaling pathways may be abnormally expressed in the anterior cingulate (ACC) and dorsolateral prefrontal cortex (DLPFC) in schizophrenia. Using western blot analysis we examined proteins of the MAPK- and cAMP-associated pathways in these two brain regions. Postmortem samples were used from a well-characterized collection of elderly patients with schizophrenia (ACC=36, DLPFC=35) and a comparison (ACC=33, DLPFC=31) group. Near-infrared intensity of IR-dye labeled secondary antisera bound to targeted proteins of the MAPK- and cAMP-associated signaling pathways was measured using LiCor Odyssey imaging system. We found decreased expression of Rap2, JNK1, JNK2, PSD-95, and decreased phosphorylation of JNK1/2 at T183/Y185 and PSD-95 at S295 in the ACC in schizophrenia. In the DLPFC, we found increased expression of Rack1, Fyn, Cdk5, and increased phosphorylation of PSD-95 at S295 and NR2B at Y1336. MAPK- and cAMP-associated molecules constitute ubiquitous intracellular signaling pathways that integrate extracellular stimuli, modify receptor expression and function, and regulate cell survival and neuroplasticity. These data suggest abnormal activity of the MAPK- and cAMP-associated pathways in frontal cortical areas in schizophrenia. These alterations may underlie the hypothesized hypoglutamatergic function in this illness. Together with previous findings, these data suggest that abnormalities of intracellular signaling pathways may contribute to the pathophysiology of schizophrenia.
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Psychopharmacological treatment of schizophrenia: What do we have, and what could we get? Neuropharmacology 2012; 62:1371-80. [DOI: 10.1016/j.neuropharm.2011.03.013] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2011] [Revised: 03/07/2011] [Accepted: 03/10/2011] [Indexed: 12/20/2022]
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Wiescholleck V, Manahan-Vaughan D. PDE4 inhibition enhances hippocampal synaptic plasticity in vivo and rescues MK801-induced impairment of long-term potentiation and object recognition memory in an animal model of psychosis. Transl Psychiatry 2012; 2:e89. [PMID: 22832854 PMCID: PMC3309535 DOI: 10.1038/tp.2012.17] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Inhibition of phosphodiesterase type 4 (PDE4) by rolipram (4-(3-(cyclopentyloxy)-4-methoxyphenyl)-pyrrolidin-2-one) has been the focus of many behavioral and molecular studies in the recent years. Rolipram exhibits memory-enhancing effects in rodents. In vitro studies have shown that long-term potentiation (LTP), which may comprise a cellular substrate for learning, is also enhanced by rolipram. However, effects have not been assessed in vivo. Rolipram has antipsychotic properties. Psychosis affects cognition and in animal models of psychosis LTP is impaired. In this study, we investigated if PDE4 inhibition improves LTP in healthy animals in vivo and if PDE4 inhibition rescues impaired LTP and prevents object recognition memory deficits in an animal model of psychosis. Recordings were made from the hippocampus of adult, freely behaving Wistar rats. Thirty minutes after treatment with rolipram or vehicle, a tetanus was applied to the medial perforant path to elicit short-term potentiation (STP) in the dentate gyrus. At this time-point, radioimmunoassay revealed that rolipram significantly elevated cyclic adenosine monophosphate levels in the dorsal hippocampus, in line with reports by others that rolipram mediates decreased PDE4 activity. In healthy animals, both intracerebroventricular and subcutaneous treatment with rolipram facilitated STP into LTP, suggesting that PDE4 inhibition may have a permissive role in plasticity mechanisms that are relevant for learning and memory. One week after a single systemic treatment with the irreversible N-methyl-D-aspartate antagonist, MK801, LTP and object recognition memory were significantly impaired, but could be rescued by PDE4 inhibition. These data suggest that the relief of cognitive disturbances in psychosis models by rolipram may be mediated in part by a rescue of hippocampal LTP.
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Affiliation(s)
- V Wiescholleck
- Medical Faculty, Department of Neurophysiology, Ruhr University Bochum, Bochum, Germany,International Graduate School of Neuroscience, Ruhr University Bochum, Bochum, Germany
| | - D Manahan-Vaughan
- Medical Faculty, Department of Neurophysiology, Ruhr University Bochum, Bochum, Germany,International Graduate School of Neuroscience, Ruhr University Bochum, Bochum, Germany,Medical Faculty, Department of Neurophysiology, Ruhr University Bochum, MA 4/149, Universitaetsstr. 150, 44780 Bochum, Germany. E-mail:
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Schwarz E, VanBeveren NJM, Guest PC, Izmailov R, Bahn S. The application of multiplexed assay systems for molecular diagnostics. INTERNATIONAL REVIEW OF NEUROBIOLOGY 2011; 101:259-278. [PMID: 22050855 DOI: 10.1016/b978-0-12-387718-5.00010-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
For decades, the diagnosis of schizophrenia and other psychiatric disorders has relied on subjective assessments such as Diagnostic and Statistical Manual criteria. There is now increasing interest in the identification of altered molecular patterns in blood and other accessible body fluids that can be used to help identify, stratify, and monitor psychiatric patients. Since shorter periods of psychosis are associated with a better prognosis, an accurate molecular test may lead to early intervention and thereby improve patient outcomes. In addition, such a test would open up the possibility to stratify more accurately the disease and could represent a novel translational medicine tool, which is crucial for the discovery and development of more efficacious therapies.
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Affiliation(s)
- Emanuel Schwarz
- Department of Chemical Engineering and Biotechnology, University of Cambridge, Cambridge, United Kingdom
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Fumagalli F, Cattaneo A, Caffino L, Ibba M, Racagni G, Carboni E, Gennarelli M, Riva MA. Sub-chronic exposure to atomoxetine up-regulates BDNF expression and signalling in the brain of adolescent spontaneously hypertensive rats: comparison with methylphenidate. Pharmacol Res 2010; 62:523-9. [PMID: 20691787 DOI: 10.1016/j.phrs.2010.07.009] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/28/2010] [Revised: 07/28/2010] [Accepted: 07/28/2010] [Indexed: 01/05/2023]
Abstract
The stimulant methylphenidate and the non-stimulant atomoxetine are widely used for the treatment of Attention-Deficit/Hyperactivity Disorder (ADHD), but the molecular mechanisms of their therapeutic action are not fully understood. The aim of our study was to investigate, in adolescent rats, the sub-chronic effect of these two drugs on neuronal plasticity, through a detailed analysis of BDNF expression and signalling in order to establish the contribution of these mechanisms in the pharmacotherapy of ADHD. Atomoxetine (ATX) up-regulated BDNF mRNA levels in the hippocampus whereas methylphenidate (MPH) increased BDNF gene expression in the nucleus accumbens and caudate-putamen. Opposite effects were seen in the prefrontal cortex, a critical region in attention disorders, where ATX increased while MPH reduced total and exon IV BDNF mRNA levels. Analysis of BDNF-mediated signalling in the prefrontal cortex revealed that ATX enhanced AKT and GSK3β phosphorylation whereas MPH reduced the synaptic levels of trkB, the high-affinity BDNF receptor, and ERK1/2 activation. Our findings show that ATX and MPH exert an opposite modulation of the BDNF system, primarily in prefrontal cortex that, independently from the behavioral control exerted by the two drugs, may be important for long-term consequences on cognitive function.
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Affiliation(s)
- Fabio Fumagalli
- Center of Neuropharmacology, Department of Pharmacological Sciences, Università degli Studi di Milano, Via Balzaretti 9, 20133 Milan, Italy
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Prenatal exposure to phencyclidine produces abnormal behaviour and NMDA receptor expression in postpubertal mice. Int J Neuropsychopharmacol 2010; 13:877-89. [PMID: 19835658 DOI: 10.1017/s1461145709990757] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
Several studies have shown the disruptive effects of non-competitive N-methyl-d-aspartate (NMDA) receptor antagonists on neurobehavioural development. Based on the neurodevelopment hypothesis of schizophrenia, there is growing interest in animal models treated with NMDA antagonists at developing stages to investigate the pathogenesis of psychological disturbances in humans. Previous studies have reported that perinatal treatment with phencyclidine (PCP) impairs the development of neuronal systems and induces schizophrenia-like behaviour. However, the adverse effects of prenatal exposure to PCP on behaviour and the function of NMDA receptors are not well understood. This study investigated the long-term effects of prenatal exposure to PCP in mice. The prenatal PCP-treated mice showed hypersensitivity to a low dose of PCP in locomotor activity and impairment of recognition memory in the novel object recognition test at age 7 wk. Meanwhile, the prenatal exposure reduced the phosphorylation of NR1, although it increased the expression of NR1 itself. Furthermore, these behavioural changes were attenuated by atypical antipsychotic treatment. Taken together, prenatal exposure to PCP produced long-lasting behavioural deficits, accompanied by the abnormal expression and dysfunction of NMDA receptors in postpubertal mice. It is worth investigating the influences of disrupted NMDA receptors during the prenatal period on behaviour in later life.
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Yasuhara A, Chaki S. Metabotropic glutamate receptors: potential drug targets for psychiatric disorders. THE OPEN MEDICINAL CHEMISTRY JOURNAL 2010; 4:20-36. [PMID: 21160908 PMCID: PMC3002053 DOI: 10.2174/1874104501004020020] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/10/2009] [Revised: 10/23/2009] [Accepted: 10/30/2009] [Indexed: 11/22/2022]
Abstract
Metabotropic glutamate receptors (mGlu receptors) have emerged as new therapeutic targets for psychiatric disorders, such as schizophrenia, depression and anxiety with their regulatory roles in glutamatergic transmissions. To date, several ligands selective for each mGlu receptor have been synthesized, and pharmacological significances of these ligands have been demonstrated in animal models. Among them, mGlu2/3 receptor agonists have been proven to be effective for treating schizophrenia and anxiety disorders in clinical studies, which may prove utilities of mGlu receptor ligands for the treatment of psychiatric disorders. This article reviews recent advances in development of each mGlu receptor ligands and their therapeutic potential.
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Affiliation(s)
- Akito Yasuhara
- Medicinal Chemistry Laboratories, Taisho Pharmaceutical Co., Ltd
| | - Shigeyuki Chaki
- Molecular Function and Pharmacology, Taisho Pharmaceutical Co., Ltd. Yoshino-cho, 1-403, kita-ku, Satitama 331-9530, Japan
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Castillo MA, Ghose S, Tamminga CA, Ulery-Reynolds PG. Deficits in syntaxin 1 phosphorylation in schizophrenia prefrontal cortex. Biol Psychiatry 2010; 67:208-16. [PMID: 19748077 DOI: 10.1016/j.biopsych.2009.07.029] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/10/2008] [Revised: 07/27/2009] [Accepted: 07/28/2009] [Indexed: 11/25/2022]
Abstract
BACKGROUND Schizophrenia has been described as a disease of the synapse. On the basis of previous studies reporting reductions in the levels and activity of CK2 (also know as casein kinase 2 or II) in the brain of subjects with schizophrenia, we hypothesized that CK2-mediated phosphorylation of the presynaptic protein syntaxin 1 (Stx 1) is deficient in schizophrenia. This in turn could affect the binding of Stx 1 to its protein partners and result in abnormal neurotransmitter release and synaptic transmission. METHODS We analyzed post mortem prefrontal cortex samples from 15 schizophrenia cases and matched controls by quantitative immunoblotting. RESULTS In addition to replicating previous findings of reduced CK2 levels, we show that as predicted, the deficit in CK2 correlates with a deficit in phospho-Stx 1. In contrast, we find that these deficits are not present in depression cases. Further, we show that the reduced levels of CK2 and phospho-Stx 1 are not due to treatment with antipsychotic drugs (APDs). In fact, APDs seem to increase both CK2 and phospho-Stx 1, suggesting that their therapeutic action may be associated with the reversal of these deficits. Finally, we show that lower phospho-Stx 1 levels are associated with reduced binding of Stx 1 to SNAP-25 and MUNC18 and decreased SNARE complex formation. CONCLUSIONS Our findings constitute the first report of altered phosphorylation of a key component for neurotransmitter release in humans and suggest that regulation of Stx 1 by CK2-mediated phosphorylation could play a role in the pathophysiology of schizophrenia.
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Affiliation(s)
- Max A Castillo
- Department of Neurology, The University of Texas, Southwestern Medical Center, Dallas, Texas, USA
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Henson MA, Roberts AC, Pérez-Otaño I, Philpot BD. Influence of the NR3A subunit on NMDA receptor functions. Prog Neurobiol 2010; 91:23-37. [PMID: 20097255 DOI: 10.1016/j.pneurobio.2010.01.004] [Citation(s) in RCA: 100] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2009] [Revised: 12/02/2009] [Accepted: 01/14/2010] [Indexed: 10/19/2022]
Abstract
Various combinations of subunits assemble to form the NMDA-type glutamate receptor (NMDAR), generating diversity in its functions. Here we review roles of the unique NMDAR subunit, NR3A, which acts in a dominant-negative manner to suppress receptor activity. NR3A-containing NMDARs display striking regional and temporal expression specificity, and, unlike most other NMDAR subtypes, they have a low conductance, are only modestly permeable to Ca(2+), and pass current at hyperpolarized potentials in the presence of magnesium. While glutamate activates triheteromeric NMDARs composed of NR1/NR2/NR3A subunits, glycine is sufficient to activate diheteromeric NR1/NR3A-containing receptors. NR3A dysfunction may contribute to neurological disorders involving NMDARs, and the subunit offers an attractive therapeutic target given its distinct pharmacological and structural properties.
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Affiliation(s)
- Maile A Henson
- Curriculum in Neurobiology, Neuroscience Center, Neurodevelopmental Disorders Research Center, Chapel Hill, NC 27599, USA
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Pakkenberg B, Scheel-Krüger J, Kristiansen LV. Schizophrenia; from structure to function with special focus on the mediodorsal thalamic prefrontal loop. Acta Psychiatr Scand 2009; 120:345-54. [PMID: 19807715 DOI: 10.1111/j.1600-0447.2009.01447.x] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
OBJECTIVE To describe structural and biochemical evidence from postmortem brains that implicates the reciprocal connections between the mediodorsal thalamic nucleus and the prefrontal cortex in cognitive symptoms of schizophrenia. METHOD The estimation of the regional volumes and cell numbers was obtained using stereological methods. The biochemical analyses of molecular expression in postmortem brain involve quantitative measurement of transcripts and proteins by in-situ (RNA) or Western blot/autoradiography in brains from patients with schizophrenia and comparison subjects. RESULTS Stereological studies in postmortem brain from patients with schizophrenia have reported divergent and often opposing findings in the total number of neurons and volume of the mediodorsal (MD) thalamic nucleus, and to a lesser degree in its reciprocally associated areas of the prefrontal cortex. Similarly, quantitative molecular postmortem studies have found large inter-subject and between-study variance at both the transcript and protein levels for receptors and their interacting molecules of several neurotransmitter systems in these interconnected anatomical regions. Combined, large variation in stereological and molecular studies indicates a complex and heterogeneous involvement of the MD thalamic-prefrontal loop in schizophrenia. CONCLUSION Based on a considerable heterogeneity in patients suffering from schizophrenia, large variation in postmortem studies, including stereological and molecular postmortem studies of the MD thalamus and frontal cortex, might be expected and may in fact partly help to explain the variable endophenotypic traits associated with this severe psychiatric illness.
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Affiliation(s)
- B Pakkenberg
- Research Laboratory for Stereology and Neuroscience, Bispebjerg University Hospital, Copenhagen, Denmark.
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NMDA receptor phosphorylation at a site affected in schizophrenia controls synaptic and behavioral plasticity. J Neurosci 2009; 29:11965-72. [PMID: 19776282 DOI: 10.1523/jneurosci.2109-09.2009] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Phosphorylation of the NR1 subunit of NMDA receptors (NMDARs) at serine (S) 897 is markedly reduced in schizophrenia patients. However, the role of NR1 S897 phosphorylation in normal synaptic function and adaptive behaviors are unknown. To address these questions, we generated mice in which the NR1 S897 is replaced with alanine (A). This knock-in mutation causes severe impairment in NMDAR synaptic incorporation and NMDAR-mediated synaptic transmission. Furthermore, the phosphomutant animals have reduced AMPA receptor (AMPAR)-mediated synaptic transmission, decreased AMPAR GluR1 subunit in the synapse, and impaired long-term potentiation. Finally, the mutant mice exhibit behavioral deficits in social interaction and sensorimotor gating. Our results suggest that an impairment in NR1 phosphorylation leads to glutamatergic hypofunction that can contribute to behavioral deficits associated with psychiatric disorders.
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Asenapine elevates cortical dopamine, noradrenaline and serotonin release. Evidence for activation of cortical and subcortical dopamine systems by different mechanisms. Psychopharmacology (Berl) 2009; 204:251-64. [PMID: 19198810 DOI: 10.1007/s00213-008-1456-5] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/25/2008] [Accepted: 12/26/2008] [Indexed: 11/27/2022]
Abstract
RATIONALE Asenapine, a psychopharmacologic agent developed for schizophrenia and bipolar disorder, has higher affinity for 5-HT(2A/C,6,7) and alpha(2) adrenergic receptors than for D(2) receptors. Asenapine exhibits potent antipsychotic-like effects without inducing catalepsy, increases cortical and subcortical dopamine release, and facilitates cortical glutamatergic transmission in rats. In this study, we further analyzed the effects of asenapine on dopaminergic, noradrenergic, and serotonergic systems in the rat brain. MATERIALS AND METHODS We studied the effects of asenapine on (1) dopaminergic neurons in the ventral tegmental area (VTA) and noradrenergic neurons in the locus coeruleus using in vivo single cell recording, (2) release of dopamine and noradrenaline (medial prefrontal cortex), serotonin (frontal cortex), and dopamine (nucleus accumbens), using in vivo microdialysis. RESULTS Systemic asenapine increased dopaminergic (0.001-0.2 mg/kg, i.v.) and noradrenergic (0.025-0.05 mg/kg i.v.) neuronal firing, and asenapine (0.1-0.2 mg/kg, s.c) increased cortical noradrenaline and serotonin output. Local asenapine administration increased all three monoamines in the cortex but did not affect accumbal dopamine output. Intra-VTA tetrodotoxin perfusion blocked asenapine-induced accumbal but not cortical dopamine outflow. CONCLUSION Asenapine at doses associated with antipsychotic activity enhanced cortical monoamine efflux. Whereas the asenapine-induced dopamine increase in nucleus accumbens is dependent on activation of dopaminergic neurons in the VTA, the increase of cortical dopamine outflow involves largely a local action at nerve terminals. Our data provide further insight on the pharmacologic characteristics of asenapine that may have bearing on its clinical efficacy in the treatment of schizophrenia and bipolar disorder.
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Elevated levels of kynurenic acid change the dopaminergic response to amphetamine: implications for schizophrenia. Int J Neuropsychopharmacol 2009; 12:501-12. [PMID: 18796185 DOI: 10.1017/s1461145708009383] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Kynurenic acid (KYNA) is an endogenous compound implicated in the pathophysiology of schizophrenia. This tryptophan metabolite antagonizes both the N-methyl-D-aspartate (NMDA) receptors and the nicotinic alpha7* receptors at micromolar concentrations. In the present study the effects of amphetamine on dopamine (DA) release in the nucleus accumbens and on firing of DA neurons in the ventral tegmental area (VTA) were investigated in rats treated with kynurenine, the precursor of KYNA, in order to elevate brain KYNA levels. In rats subchronically treated with kynurenine (90 mg/kg x d for 6 d via osmotic minipumps, resulting in a 2-fold increase in whole-brain KYNA), the amphetamine-induced (2 mg/kg i.p.) increase in accumbal DA release was clearly enhanced compared to controls. Furthermore, subchronic treatment with kynurenine reduced the inhibitory action of amphetamine (0.2-25.6 mg/kg i.v.) on firing rate and burst firing activity of VTA DA neurons. A single dose of kynurenine (5 mg/kg s.c., 60 min, resulting in a 3-fold increase in whole-brain KYNA) did not alter the amphetamine-induced effects on DA neurotransmission compared to control rats. Present data are in agreement with the increased striatal DA release by amphetamine as observed by brain-imaging studies in patients with schizophrenia. Thus, subchronic elevation of rat brain KYNA, may rationally serve as an animal model similar to a pathophysiological condition of schizophrenia. It is proposed that the reduced responsivity of VTA DA neurons to the inhibitory action of amphetamine observed in rats with subchronically elevated KYNA levels may partly account for the increase in terminal DA release.
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Lei G, Anastasio NC, Fu Y, Neugebauer V, Johnson KM. Activation of dopamine D1 receptors blocks phencyclidine-induced neurotoxicity by enhancing N-methyl-D-aspartate receptor-mediated synaptic strength. J Neurochem 2009; 109:1017-30. [PMID: 19519774 DOI: 10.1111/j.1471-4159.2009.06030.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Early postnatal blockade of NMDA receptors by phencyclidine (PCP) causes cortical apoptosis in animals. This is associated with the development of schizophrenia-like behaviors in rats later in life. Recent studies show that the mechanism involves a loss of neurotrophic support from the phosphoinositol-3 kinase/Akt pathway, which is normally maintained by synaptic NMDA receptor activation. Here we report that activation of dopamine D1 receptors (D1R) with dihydrexidine (DHX) prevents PCP-induced neurotoxicity in cortical neurons by enhancing the efficacy of NMDAergic synapses. DHX increases serine phosphorylation of the NR1 subunit through protein kinase A activation and tyrosine phosphorylation of the NR2B subunit via Src kinase. DHX enhances recruitment of NR1 and NR2B, but not NR2A, into synapses. DHX also facilitated the synaptic response in cortical slices and this was blocked by an NR2B antagonist. DHX pre-treatment of rat pups prior to PCP on postnatal days 7, 9 and 11 inhibited PCP-induced caspase-3 activation on PN11 and deficits in pre-pulse inhibition of acoustic startle measured on PN 26-28. In summary, these data demonstrate that PCP-induced deficits in NMDA receptor function, neurotoxicity and subsequent behavioral deficits may be prevented by D1R activation in the cortex and further, it is suggested that D1R activation may be beneficial in treating schizophrenia.
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Affiliation(s)
- Gang Lei
- Department of Pharmacology and Toxicology, University of Texas Medical Branch, Galveston, Texas 77555-1031, USA
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Lieberman JA, Bymaster FP, Meltzer HY, Deutch AY, Duncan GE, Marx CE, Aprille JR, Dwyer DS, Li XM, Mahadik SP, Duman RS, Porter JH, Modica-Napolitano JS, Newton SS, Csernansky JG. Antipsychotic drugs: comparison in animal models of efficacy, neurotransmitter regulation, and neuroprotection. Pharmacol Rev 2009; 60:358-403. [PMID: 18922967 DOI: 10.1124/pr.107.00107] [Citation(s) in RCA: 172] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Various lines of evidence indicate the presence of progressive pathophysiological processes occurring within the brains of patients with schizophrenia. By modulating chemical neurotransmission, antipsychotic drugs may influence a variety of functions regulating neuronal resilience and viability and have the potential for neuroprotection. This article reviews the current literature describing preclinical and clinical studies that evaluate the efficacy of antipsychotic drugs, their mechanism of action and the potential of first- and second-generation antipsychotic drugs to exert effects on cellular processes that may be neuroprotective in schizophrenia. The evidence to date suggests that although all antipsychotic drugs have the ability to reduce psychotic symptoms via D(2) receptor antagonism, some antipsychotics may differ in other pharmacological properties and their capacities to mitigate and possibly reverse cellular processes that may underlie the pathophysiology of schizophrenia.
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Affiliation(s)
- Jeffrey A Lieberman
- Department of Psychiatry, Columbia University College of Physicians and Surgeons and the New York State Psychiatric Institute, 1051 Riverside Dr., Unit 4, New York, NY 10032, USA.
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Improvement of phencyclidine-induced social behaviour deficits in rats: Involvement of 5-HT1A receptors. Behav Brain Res 2008; 191:26-31. [DOI: 10.1016/j.bbr.2008.03.018] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2008] [Revised: 02/25/2008] [Accepted: 03/03/2008] [Indexed: 11/23/2022]
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Shuffling the Deck Anew: How NR3 Tweaks NMDA Receptor Function. Mol Neurobiol 2008; 38:16-26. [DOI: 10.1007/s12035-008-8029-9] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2008] [Accepted: 05/16/2008] [Indexed: 10/21/2022]
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Blanke ML, VanDongen AMJ. The NR1 M3 domain mediates allosteric coupling in the N-methyl-D-aspartate receptor. Mol Pharmacol 2008; 74:454-65. [PMID: 18483226 DOI: 10.1124/mol.107.044115] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
N-Methyl-D-aspartate (NMDA) receptors play a critical role in both development of the central nervous system and adult neuroplasticity. However, although the NMDA receptor presents a valuable therapeutic target, the relationship between its structure and functional properties has yet to be fully elucidated. To further explore the mechanism of receptor activation, we characterized two gain-of-function mutations within the NR1 M3 segment, a transmembrane domain proposed to couple ligand binding and channel opening. Both mutants (A7Q and A7Y) displayed significant glycine-independent currents, indicating that their M3 domains may preferentially adopt a more activated conformation. Substituted cysteine modification experiments revealed that the glycine binding clefts of both A7Q and A7Y are inaccessible to modifying reagents and resistant to competitive antagonism. These data suggest that perturbation of M3 can stabilize the ligand binding domain in a closed cleft conformation, even in the absence of agonist. Both mutants also displayed significant glutamate-independent current and insensitivity to glutamate-site antagonism, indicating partial activation by either glycine or glutamate alone. Furthermore, A7Q and A7Y increased accessibility of the NR2 M3 domain, providing evidence for intersubunit coupling at the transmembrane level and suggesting that these NR1 mutations dominate the properties of the intact heteromeric receptor. The equivalent mutations in NR2 did not exhibit comparable phenotypes, indicating that the NR1 and NR2 M3 domains may play different functional roles. In summary, our data demonstrate that the NR1 M3 segment is functionally coupled to key structural domains in both the NR1 and NR2 subunits.
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Affiliation(s)
- Marie L Blanke
- Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, North Carolin, USA
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Blanke ML, VanDongen AMJ. Constitutive activation of the N-methyl-D-aspartate receptor via cleft-spanning disulfide bonds. J Biol Chem 2008; 283:21519-29. [PMID: 18450751 DOI: 10.1074/jbc.m709190200] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Although the N-methyl-D-aspartate (NMDA) receptor plays a critical role in the central nervous system, many questions remain regarding the relationship between its structure and functional properties. In particular, the involvement of ligand-binding domain closure in determining agonist efficacy, which has been reported in other glutamate receptor subtypes, remains unresolved. To address this question, we designed dual cysteine point mutations spanning the NR1 and NR2 ligand-binding clefts, aiming to stabilize these domains in closed cleft conformations. Two mutants, E522C/I691C in NR1 (EI) and K487C/N687C in NR2 (KN) were found to exhibit significant glycine- and glutamate-independent activation, respectively, and co-expression of the two subunits produced a constitutively active channel. However, both individual mutants could be activated above constitutive levels in a concentration-dependent manner, indicating that cleft closure does not completely prevent agonist association. Interestingly, whereas the NR2 KN disulfide was found to potentiate channel gating and M3 accessibility, NR1 EI exhibited the opposite phenotype, suggesting that the EI disulfide may trap the NR1 ligand-binding domain in a lower efficacy conformation. Furthermore, both mutants affected agonist sensitivity at the opposing subunit, suggesting that closed cleft stabilization may contribute to coupling between the subunits. These results support a correlation between cleft stability and receptor activation, providing compelling evidence for the Venus flytrap mechanism of glutamate receptor domain closure.
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Affiliation(s)
- Marie L Blanke
- Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, NC 27710, USA
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Bubeníková-Valesová V, Horácek J, Vrajová M, Höschl C. Models of schizophrenia in humans and animals based on inhibition of NMDA receptors. Neurosci Biobehav Rev 2008; 32:1014-23. [PMID: 18471877 DOI: 10.1016/j.neubiorev.2008.03.012] [Citation(s) in RCA: 239] [Impact Index Per Article: 14.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2007] [Revised: 03/18/2008] [Accepted: 03/28/2008] [Indexed: 01/17/2023]
Abstract
The research of the glutamatergic system in schizophrenia has advanced with the use of non-competitive antagonists of glutamate NMDA receptors (phencyclidine, ketamine, and dizocilpine), which change both human and animal behaviour and induce schizophrenia-like manifestations. Models based on both acute and chronic administration of these substances in humans and rats show phenomenological validity and are suitable for searching for new substances with antipsychotic effects. Nevertheless, pathophysiology of schizophrenia remains unexplained. In the light of the neurodevelopmental model of schizophrenia based on early administration of NMDA receptor antagonists it seems that increased cellular destruction by apoptosis or changes in function of glutamatergic NMDA receptors in the early development of central nervous system are decisive for subsequent development of psychosis, which often does not manifest itself until adulthood. Chronic administration of antagonists initializes a number of adaptation mechanisms, which correlate with findings obtained in patients with schizophrenia; therefore, this model is also suitable for research into pathophysiology of this disease.
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Frånberg O, Wiker C, Marcus MM, Konradsson A, Jardemark K, Schilström B, Shahid M, Wong EHF, Svensson TH. Asenapine, a novel psychopharmacologic agent: preclinical evidence for clinical effects in schizophrenia. Psychopharmacology (Berl) 2008; 196:417-29. [PMID: 17940749 DOI: 10.1007/s00213-007-0973-y] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/16/2007] [Accepted: 10/01/2007] [Indexed: 11/29/2022]
Abstract
RATIONALE Asenapine is a novel psychopharmacologic agent being developed for the treatment of schizophrenia and bipolar disorder. MATERIALS AND METHODS The present study was undertaken to investigate the effects of asenapine using animal models predictive of antipsychotic efficacy (conditioned avoidance response [CAR]) and extrapyramidal side effects (EPS; catalepsy). In parallel, the effects of asenapine on regional dopamine output using in vivo microdialysis in freely moving rats, dopamine output in the core and shell subregions of nucleus accumbens (NAc) using in vivo voltammetry in anesthetized rats, and N-methyl-D: -aspartate (NMDA)-induced currents in pyramidal neurons of the medial prefrontal cortex (mPFC) using the electrophysiological technique intracellular recording in vitro were assessed. RESULTS Asenapine (0.05-0.2 mg/kg, subcutaneous [s.c.]) induced a dose-dependent suppression of CAR (no escape failures recorded) and did not induce catalepsy. Asenapine (0.05-0.2 mg/kg, s.c.) increased dopamine efflux in both the mPFC and the NAc. Low-dose asenapine (0.01 mg/kg, intravenous [i.v.]) increased dopamine efflux preferentially in the shell compared to the core of NAc, whereas at a higher dose (0.05 mg/kg, i.v.), the difference disappeared. Finally, like clozapine (100 nM), but at a considerably lower concentration (5 nM), asenapine significantly potentiated the NMDA-induced responses in pyramidal cells of the mPFC. CONCLUSIONS These preclinical data suggest that asenapine may exhibit highly potent antipsychotic activity with very low EPS liability. Its ability to increase both dopaminergic and glutamatergic activity in rat mPFC suggests that asenapine may possess an advantageous effect not only on positive symptoms in patients with schizophrenia, but also on negative and cognitive symptoms.
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Affiliation(s)
- Olivia Frånberg
- Department of Physiology and Pharmacology, Karolinska Institutet, Nanna Svartz väg 2, 171 77, Stockholm, Sweden
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Ishikawa M, Mizukami K, Iwakiri M, Asada T. Immunohistochemical and immunoblot analysis of Dopamine and cyclic AMP-regulated phosphoprotein, relative molecular mass 32,000 (DARPP-32) in the prefrontal cortex of subjects with schizophrenia and bipolar disorder. Prog Neuropsychopharmacol Biol Psychiatry 2007; 31:1177-81. [PMID: 17521792 DOI: 10.1016/j.pnpbp.2007.04.013] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/27/2006] [Revised: 03/24/2007] [Accepted: 04/16/2007] [Indexed: 11/17/2022]
Abstract
Dopamine and cyclic adenosine 3':5'-monophosphate (AMP)-regulated phosphoprotein, relative molecular mass 32,000 (DARPP-32), plays an important role in modulating the functions of various neurotransmitter systems. To explore the alterations in DARPP-32 in subjects with schizophrenia and bipolar disorder, we employed immunohistochemical and Western blotting techniques and examined the distribution and expression of DARPP-32 in the postmortem dorsolateral prefrontal cortex (DLPFC) from 12 subjects with schizophrenia, 10 subjects with bipolar disorder, and 11 control subjects. Immunohistochemical study demonstrated that DARPP-32 immunolabeling in the neuronal soma from subjects with schizophrenia and bipolar disorder was lower than in that from the controls. The results of the immunoblot analysis were consistent with those of the immunohistochemistry, and the amount of DARPP-32 in subjects with schizophrenia and bipolar disorder was found to be lower than that in the control subjects. The present study suggests that DARPP-32 decreases in the DLPFC of patients with schizophrenia and bipolar disorder, and further suggests that this decrease is associated with dysfunction of dopaminoceptive neurons in the DLPFC of patients affected by these two mental disorders.
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Affiliation(s)
- Masanori Ishikawa
- Department of Psychiatry, Institute of Clinical Medicine, University of Tsukuba, 1-1-1 Tennodai, Tsukuba City, Ibaraki 305-8575, Japan
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