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Abstract
Established treatments for obsessive-compulsive disorder (OCD) are of benefit in approximately 3 of every 4 patients, but refractory disease remains distressingly common, and many treatment responders continue to experience considerable morbidity. This motivates a search for new insights into pathophysiology that may inform novel treatment strategies. Much recent work has focused on the neurotransmitter glutamate. Several lines of neurochemical and genetic evidence suggests that glutamate dysregulation may contribute to OCD, although much remains unclear. The off-label use of a number of pharmacological agents approved for other indications has been investigated in refractory OCD. We summarize investigations of memantine, riluzole, ketamine, D-cycloserine, glycine, N-acetylserine, topiramate, and lamotrigine. Evidence exists for benefit from each of these in some patients; though none has been proven effective with sufficient clarity to be considered part of standard care, these agents are options in individuals whose symptoms are refractory to better-established therapeutic strategies.
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Affiliation(s)
- Christopher Pittenger
- Departments of Psychiatry and Psychology, Child Study Center, and Interdepartmental Neuroscience Program, Yale University School of Medicine
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52
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Decreased thalamic glutamate level in unmedicated adult obsessive-compulsive disorder patients detected by proton magnetic resonance spectroscopy. J Affect Disord 2015; 178:193-200. [PMID: 25819113 DOI: 10.1016/j.jad.2015.03.008] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/30/2014] [Revised: 03/05/2015] [Accepted: 03/05/2015] [Indexed: 01/21/2023]
Abstract
BACKGROUND Previous neuroimaging studies implied that the dysfunction of cortico-striato-thalamo-cortical (CSTC) circuit served as the neural basis for the pathophysiology of obsessive-compulsive disorder (OCD). The imbalances in neuronal metabolite and neurotransmitter within CSTC circuit have been shown as the leading reasons of the OCD onset. The aim of this study is to investigate the metabolic alterations, especially the glutamatergic signal dysfunction within CSTC circuit, and the relationships between neural metabolites and the symptom severity of OCD patients. METHODS Single voxel magnetic resonance spectroscopy (MRS) was conducted in medial prefrontal cortex (mPFC) and bilateral thalamus areas for thirteen unmedicated adult OCD patients with age-, gender-, and education-matched healthy controls. Quantification and multivariate analysis were performed to identify vital metabolic biomarkers for patients and healthy controls group differentiation. Moreover, we performed Spearman׳s rank correlation analysis for OCD patients to examine the relationship between the metabolite concentration level and OCD symptomatology. RESULTS Patients with OCD showed significantly decreased glutamate level in mPFC (p=0.021) and right thalamus (p=0.039), and significantly increased choline compounds in left thalamus (p=0.044).The glutamate in right thalamus was shown as the most important metabolite for group separation from multivariate analysis (Q(2)=0.134) and was significantly correlated with the patients׳ compulsion scores (Spearman r=-0.674, p=0.016). LIMITATIONS Limited sample size, the use of creatine and phosphocreatine (Cr) ratios rather than absolute concentrations and unresolved glutamine (Gln) are limitations of the present study. CONCLUSION Our study results consolidated the hypothesis about glutamatergic signaling dysfunction in OCD. To our knowledge, it is the first finding about a reduced thalamic glutamate level in adult unmedicated OCD patients. The dysregulation of glutamate serves as a potential target for the OCD pharmacotherapy and the detailed mechanisms underlying the glutamate alterations within CSTC circuits merit further investigations.
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Hussain A, Dar MA, Wani RA, Shah MS, Jan MM, Malik YA, Chandel RK, Margoob MA. Role of lamotrigine augmentation in treatment-resistant obsessive compulsive disorder: a retrospective case review from South Asia. Indian J Psychol Med 2015; 37:154-8. [PMID: 25969599 PMCID: PMC4418246 DOI: 10.4103/0253-7176.155613] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
BACKGROUND Resistance to pharmacotherapy is one of the major challenges in the management of obsessive-compulsive disorder (OCD). OCD being a quite prevalent disorder, this resistance adds to the disability. Different strategies are being employed to counter this resistance, one of them being augmentation with glutamatergic modulators. Lamotrigine is being used for same since the recent past with mixed results. OBJECTIVE The aim was to study the role of lamotrigine augmentation in serotonin reuptake inhibitor (SRI) resistant OCD patients. METHODOLOGY AND RESULTS This study was carried by studying the case sheets of SRI resistant cases having already completed the treatment. A total of 22 cases sheets over 2 years met the study criteria with a mean age of mean age of 34.14 years. Over a period of 16 weeks, with a mean lamotrigine dose of 150 mg/day, 20 out of 22 patients had shown a significant response. The mean decrease in Yale-Brown Obsessive Compulsive Scale score was 67.23% with a baseline score of 28.87. There was a similar change on different domains of World Health Organization quality of life (P = 0.00564). CONCLUSION Lamotrigine augmentation to on-going treatment with SRIs may be an effective move in case of SRI resistant OCD patients.
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Affiliation(s)
- Arshad Hussain
- Department of Psychiatry, Government Medical College, Srinagar, Jammu and Kashmir, India
| | - Mansoor Ahmad Dar
- Department of Psychiatry, Government Medical College, Srinagar, Jammu and Kashmir, India
| | - Rayees Ahmad Wani
- Department of Psychiatry, Government Medical College, Srinagar, Jammu and Kashmir, India
| | - Majid Shafi Shah
- Department of Psychiatry, Government Medical College, Srinagar, Jammu and Kashmir, India
| | - Mohd Muzzaffar Jan
- Department of Psychiatry, Government Medical College, Srinagar, Jammu and Kashmir, India
| | - Yasir A Malik
- Department of Psychiatry, Government Medical College, Srinagar, Jammu and Kashmir, India
| | - Rajesh Kumar Chandel
- Department of Psychiatry, Government Medical College, Srinagar, Jammu and Kashmir, India
| | - Mushtaq Ahmad Margoob
- Department of Psychiatry, Government Medical College, Srinagar, Jammu and Kashmir, India
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Serata D, Kotzalidis GD, Rapinesi C, Janiri D, Di Pietro S, Callovini G, Piacentino D, Gasperoni C, Brugnoli R, Ferri VR, Girardi N, Tatarelli R, Ferracuti S, Angeletti G, Girardi P, Del Casale A. Are 5-HT3 antagonists effective in obsessive-compulsive disorder? A systematic review of literature. Hum Psychopharmacol 2015; 30:70-84. [PMID: 25676060 DOI: 10.1002/hup.2461] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/15/2014] [Revised: 11/25/2014] [Accepted: 12/12/2014] [Indexed: 12/18/2022]
Abstract
OBJECTIVE The purpose of this literature database search-based review was to critically consider and evaluate the findings of literature focusing on efficacy and safety of 5-HT3 antagonists in the treatment of obsessive-compulsive disorder (OCD), so as to test whether preclinical data match clinical therapeutic trials. DESIGN The PubMed database has been searched for papers on 5-HT3 antagonists and OCD in humans and for animal models of OCD and 5-HT3 receptors. RESULTS Of the clinically tested 5-HT3 receptor antagonists, ondansetron has been used to treat OCD in five therapeutic studies, whereas granisetron only in one recent trial. Both showed some efficacy in open studies and superiority to placebo in double-blind studies, along with fair safety. No animal OCD model directly implicated 5-HT3 receptors. CONCLUSIONS Overall, results indicate some utility, but the available literature is too scanty to allow for valid conclusions to be drawn. The mismatch between animal models of obsessive-compulsive disorder and clinical data with 5-HT3 antagonists needs more clinical data to ensure that it is not an artefact.
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Affiliation(s)
- Daniele Serata
- Neurosciences, Mental Health, and Sensory Organs (NeSMOS) Department, School of Medicine and Psychology, Sapienza University of Rome, UOC Psychiatry, Sant'Andrea Hospital, Roma, Italy; Department of Neuropsychiatry, Villa Rosa Suore Ospedaliere of the Sacred Heart of Jesus, Viterbo, Italy
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Ortiz AE, Ortiz AG, Falcon C, Morer A, Plana MT, Bargalló N, Lázaro L. 1H-MRS of the anterior cingulate cortex in childhood and adolescent obsessive-compulsive disorder: a case-control study. Eur Neuropsychopharmacol 2015; 25:60-8. [PMID: 25499604 DOI: 10.1016/j.euroneuro.2014.11.007] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/17/2014] [Revised: 10/01/2014] [Accepted: 11/08/2014] [Indexed: 02/08/2023]
Abstract
Abnormal glutamate concentrations in the anterior cingulate cortex (ACC) have been identified in children and adults with obsessive-compulsive disorder (OCD). The purpose of the present study was to measure in vivo (1)H-MRS neurometabolite concentrations in the ACC of children and adolescents with OCD, in order to identify metabolite abnormalities compared to healthy controls and to assess their relationship with clinical variables. 3T proton-magnetic resonance spectroscopy was used to probe ACC biochemistry in 47 paediatric and adolescent OCD patients (11-18 years old) compared to 31 healthy subjects of similar age, sex and estimated intellectual quotient. There were no significant differences in the concentration of glutamate plus glutamine (Glx) adjusted for CSF between OCD patients and healthy controls [F1,74=0.00; P=0.943], but there were significant differences in the concentration of Glx adjusted for CSF in paediatric and adolescent OCD patients according to duration of illness (less than or more than 24 months) [F2,73=3.95; P=0.024]. In addition, we found significantly lower levels of myo-inositol adjusted for CSF in the ACC [F1,74=5.686; P=0.02] in patients compared with controls. The present findings do not confirm the hypothesis of differences in Glx concentrations in the ACC between children and adolescents with OCD and healthy controls; however, the observation of differences in the Glx concentration in children and adolescent OCD patients depending on the duration of illness is of interest.
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Affiliation(s)
- A E Ortiz
- Department of Child and Adolescent Psychiatry and Psychology, Institute of Neurosciences, Hospital Clinic de Barcelona, Spain.
| | - A G Ortiz
- Department of Child and Adolescent Psychiatry and Psychology, Institute of Neurosciences, Hospital Clinic de Barcelona, Spain
| | - C Falcon
- Centro de Investigación Nacional en Red en Bioingeniería, Biomateriales y Nanomedicina, CIBER-BBN, Spain
| | - A Morer
- Department of Child and Adolescent Psychiatry and Psychology, Institute of Neurosciences, Hospital Clinic de Barcelona, Spain; Centro de Investigación Biomédica en Red de Salud Mental CIBERSAM, Spain
| | - M T Plana
- Department of Child and Adolescent Psychiatry and Psychology, Institute of Neurosciences, Hospital Clinic de Barcelona, Spain
| | - N Bargalló
- Image diagnostic Center, Hospital Clinic de Barcelona, Spain; Centro de Investigación Biomédica en Red de Salud Mental CIBERSAM, Spain; Medical Image Core Facility, IDIBAPS (Institut d׳Investigacions Biomèdiques August Pi i Sunyer), Spain
| | - L Lázaro
- Department of Child and Adolescent Psychiatry and Psychology, Institute of Neurosciences, Hospital Clinic de Barcelona, Spain; Centro de Investigación Biomédica en Red de Salud Mental CIBERSAM, Spain; Medical Image Core Facility, IDIBAPS (Institut d׳Investigacions Biomèdiques August Pi i Sunyer), Spain; Department of Psychiatry and Clinical Psychobiology, Health Sciences Division, University of Barcelona, Spain
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56
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Kuo JR, Lin SS, Liu J, Chen SH, Chio CC, Wang JJ, Liu JM. Deep brain light stimulation effects on glutamate and dopamine concentration. BIOMEDICAL OPTICS EXPRESS 2015; 6:23-31. [PMID: 25657871 PMCID: PMC4317125 DOI: 10.1364/boe.6.000023] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/17/2014] [Revised: 11/12/2014] [Accepted: 11/14/2014] [Indexed: 06/04/2023]
Abstract
Compared to deep brain electrical stimulation, which has been applied to treating pathological brain diseases, little work has been done on the effect of deep brain light stimulation. A fiber-coupled laser stimulator at 840 nm wavelength and 130 Hz pulse repetition rate is developed in this work for deep brain light stimulation in a rat model. Concentration changes in glutamate and dopamine in the striatum are observed using a microdialysis probe when the subthalamic nucleus (STN) is stimulated at various optical power levels. Experimental results show that light stimulation causes the concentration of glutamate to decrease while that of dopamine is increased. This suggests that deep brain light stimulation of the STN is a promising therapeutic strategy for dopamine-related diseases such as Parkinson's disease. The stimulator developed for this work is useful for deep brain light stimulation in biomedical research.
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Affiliation(s)
- Jinn-Rung Kuo
- Departments of Neurosurgery, Chi-Mei Medical Center, Tainan,
Taiwan
- Department of Biotechnology, Southern Taiwan University of Science and Technology, Tainan,
Taiwan
| | - Shih-Shian Lin
- Neurophotonics Laboratory, College of Photonics, National Chiao Tung University, Tainan,
Taiwan
| | - Janelle Liu
- Neuroscience Interdepartmental Program, University of California, Los Angeles, Los Angeles, CA,
USA
| | - Shih-How Chen
- Neurophotonics Laboratory, College of Photonics, National Chiao Tung University, Tainan,
Taiwan
| | - Chung-Chin Chio
- Departments of Neurosurgery, Chi-Mei Medical Center, Tainan,
Taiwan
| | - Jhi-Joung Wang
- Medical Research, Chi-Mei Medical Center, Tainan,
Taiwan
| | - Jia-Ming Liu
- Neurophotonics Laboratory, College of Photonics, National Chiao Tung University, Tainan,
Taiwan
- Department of Electrical Engineering, University of California, Los Angeles, Los Angeles, CA,
USA
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57
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Amantadine augmentation therapy for obsessive compulsive patients resistant to SSRIs-an open-label study. Clin Neuropharmacol 2014; 37:79-81. [PMID: 24824662 DOI: 10.1097/wnf.0000000000000029] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND It has been hypothesized that glutamatergic dysfunction may play a role in the development of obsessive compulsive disorder (OCD) and that glutamatergic modulation may ameliorate some of the OC symptoms. We evaluated the effectiveness of amantadine (AMN)- a weak, noncompetitive, antagonist of the N-methyl-D-aspartic acid (NMDA) receptor-as an adjunctive therapy to selective serotonin reuptake inhibitors (SSRIs), and its role in improving OC symptoms in cases refractory to SSRI pharmacotherapy alone. METHODS Eight patients (5 males and 3 females, aged 42.6 ± 13.1 years) that met Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, Text Revision criteria for OCD, scored above 20 points on Yale Brown Obsessive Compulsive Scale (Y-BOCS) and were unresponsive to at least one SSRI, completed an open label study of 6 weeks duration. AMN was added to the current stable SSRI regimen and baseline and endpoint changes in Y-BOCS, depression and anxiety levels were analyzed. RESULTS Significant reductions in total Y-BOCS (28 ± 4.5 vs. 18.8 ± 8.8; P < 0.01; df = 7; t = 2.36), Y-BOCS compulsion sub-scale (15.3 ± 3.2 vs. 10.6 ± 4.7; P < 0.02; df = 7; t = 2.36), and Y-BOCS obsession sub-scale (12.7 ± 3.3 vs. 8.1 ± 5; P < 0.05; df = 7; t = 2.36) scores were obtained at endpoint. The anxiety and depression levels remained unaltered. CONCLUSIONS AMN adjunction to SSRI treatment may lead to a significant reduction in OC symptoms, supporting the hypothesis that transduction of the glutamate signal via NMDA receptor may play a role in OCD. A large scale, double-blind, placebo-controlled study is warranted to confirm our results.
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58
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Cappi C, Hounie AG, Mariani DB, Diniz JB, Silva ART, Reis VNS, Busso AF, Silva AG, Fidalgo F, Rogatto SR, Miguel EC, Krepischi AC, Brentani H. An inherited small microdeletion at 15q13.3 in a patient with early-onset obsessive-compulsive disorder. PLoS One 2014; 9:e110198. [PMID: 25303678 PMCID: PMC4193873 DOI: 10.1371/journal.pone.0110198] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2013] [Accepted: 09/18/2014] [Indexed: 01/22/2023] Open
Abstract
Copy number variations (CNVs) have been previously associated with several different neurodevelopmental psychiatric disorders, such as autism, schizophrenia, and attention deficit hyperactivity disorder (ADHD). The present study consisted of a pilot genome-wide screen for CNVs in a cohort of 16 patients with early-onset obsessive-compulsive disorder (OCD) and 12 mentally healthy individuals, using array-based comparative genomic hybridization (aCGH) on 44K arrays. A small rare paternal inherited microdeletion (∼64 kb) was identified in chromosome 15q13.3 of one male patient with very early onset OCD. The father did not have OCD. The deletion encompassed part of the FMN1 gene, which is involved with the glutamatergic system. This finding supports the hypothesis of a complex network of several genes expressed in the brain contributing for the genetic risk of OCD, and also supports the glutamatergic involvement in OCD, which has been previously reported in the literature.
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Affiliation(s)
- Carolina Cappi
- Institute and Department of Psychiatry, São Paulo University Medical School, São Paulo, Brazil
| | - Ana Gabriela Hounie
- Institute and Department of Psychiatry, São Paulo University Medical School, São Paulo, Brazil
- Federal University of São Paulo-UPIA-UNIFESP, São Paulo, Brazil
| | - Daniel B. Mariani
- Inter-institutional Grad Program on Bioinformatics, Institute of Mathematics and Statistics, São Paulo University, São Paulo, Brazil
| | - Juliana Belo Diniz
- Institute and Department of Psychiatry, São Paulo University Medical School, São Paulo, Brazil
| | - Aderbal R. T. Silva
- Institute and Department of Psychiatry, São Paulo University Medical School, São Paulo, Brazil
| | - Viviane N. S. Reis
- Institute and Department of Psychiatry, São Paulo University Medical School, São Paulo, Brazil
| | - Ariane F. Busso
- International Research Center, AC Camargo Cancer Center, São Paulo, Brazil
| | | | - Felipe Fidalgo
- International Research Center, AC Camargo Cancer Center, São Paulo, Brazil
| | | | - Euripedes C. Miguel
- Institute and Department of Psychiatry, São Paulo University Medical School, São Paulo, Brazil
| | - Ana C. Krepischi
- International Research Center, AC Camargo Cancer Center, São Paulo, Brazil
| | - Helena Brentani
- Institute and Department of Psychiatry, São Paulo University Medical School, São Paulo, Brazil
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59
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Tang R, Noh HJ, Wang D, Sigurdsson S, Swofford R, Perloski M, Duxbury M, Patterson EE, Albright J, Castelhano M, Auton A, Boyko AR, Feng G, Lindblad-Toh K, Karlsson EK. Candidate genes and functional noncoding variants identified in a canine model of obsessive-compulsive disorder. Genome Biol 2014; 15:R25. [PMID: 24995881 PMCID: PMC4038740 DOI: 10.1186/gb-2014-15-3-r25] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2013] [Accepted: 03/14/2014] [Indexed: 12/30/2022] Open
Abstract
BACKGROUND Obsessive-compulsive disorder (OCD), a severe mental disease manifested in time-consuming repetition of behaviors, affects 1 to 3% of the human population. While highly heritable, complex genetics has hampered attempts to elucidate OCD etiology. Dogs suffer from naturally occurring compulsive disorders that closely model human OCD, manifested as an excessive repetition of normal canine behaviors that only partially responds to drug therapy. The limited diversity within dog breeds makes identifying underlying genetic factors easier. RESULTS We use genome-wide association of 87 Doberman Pinscher cases and 63 controls to identify genomic loci associated with OCD and sequence these regions in 8 affected dogs from high-risk breeds and 8 breed-matched controls. We find 119 variants in evolutionarily conserved sites that are specific to dogs with OCD. These case-only variants are significantly more common in high OCD risk breeds compared to breeds with no known psychiatric problems. Four genes, all with synaptic function, have the most case-only variation: neuronal cadherin (CDH2), catenin alpha2 (CTNNA2), ataxin-1 (ATXN1), and plasma glutamate carboxypeptidase (PGCP). In the 2 Mb gene desert between the cadherin genes CDH2 and DSC3, we find two different variants found only in dogs with OCD that disrupt the same highly conserved regulatory element. These variants cause significant changes in gene expression in a human neuroblastoma cell line, likely due to disrupted transcription factor binding. CONCLUSIONS The limited genetic diversity of dog breeds facilitates identification of genes, functional variants and regulatory pathways underlying complex psychiatric disorders that are mechanistically similar in dogs and humans.
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Affiliation(s)
- Ruqi Tang
- Broad Institute of MIT and Harvard, 7 Cambridge Center, Cambridge, MA 02142, USA
- McGovern Institute for Brain Research and Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
- Renji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai 200127, China
| | - Hyun Ji Noh
- Broad Institute of MIT and Harvard, 7 Cambridge Center, Cambridge, MA 02142, USA
| | - Dongqing Wang
- McGovern Institute for Brain Research and Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Snaevar Sigurdsson
- Broad Institute of MIT and Harvard, 7 Cambridge Center, Cambridge, MA 02142, USA
| | - Ross Swofford
- Broad Institute of MIT and Harvard, 7 Cambridge Center, Cambridge, MA 02142, USA
| | - Michele Perloski
- Broad Institute of MIT and Harvard, 7 Cambridge Center, Cambridge, MA 02142, USA
| | - Margaret Duxbury
- College of Veterinary Medicine, University of Minnesota, St. Paul, MN 55108, USA
| | - Edward E Patterson
- College of Veterinary Medicine, University of Minnesota, St. Paul, MN 55108, USA
| | - Julie Albright
- Department of Clinical Sciences, College of Veterinary Medicine, Cornell University, Ithaca, NY 14853, USA
| | - Marta Castelhano
- Department of Clinical Sciences, College of Veterinary Medicine, Cornell University, Ithaca, NY 14853, USA
| | - Adam Auton
- Department of Genetics, Albert Einstein College of Medicine, 1301 Morris Park Avenue, Van Etten B06, Bronx, NY 10461, USA
| | - Adam R Boyko
- Department of Biomedical Sciences, Cornell University, Ithaca, NY 14853, USA
| | - Guoping Feng
- Broad Institute of MIT and Harvard, 7 Cambridge Center, Cambridge, MA 02142, USA
- McGovern Institute for Brain Research and Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Kerstin Lindblad-Toh
- Broad Institute of MIT and Harvard, 7 Cambridge Center, Cambridge, MA 02142, USA
- Science for Life Laboratory, Department of Medical Biochemistry and Microbiology, Uppsala University, Uppsala 75237, Sweden
| | - Elinor K Karlsson
- Broad Institute of MIT and Harvard, 7 Cambridge Center, Cambridge, MA 02142, USA
- Center for Systems Biology, Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA 02138, USA
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Abstract
PURPOSE OF REVIEW Evidence-based pharmacological interventions for obsessive compulsive disorder (OCD) are targeted mainly at the serotonergic and dopaminergic pathways, and are not always effective. It is timely to review the growing evidence from animal models and clinical research (e.g., brain imaging, genetics) on the role of the glutamatergic system in OCD. RECENT FINDINGS Emerging evidence from both animal models and clinical research (including brain imaging, neurogenetics) supports the glutamatergic system as a potential target for pharmacotherapy in OCD. Although there have been relatively few randomized controlled trials of glutamatergic agents in pediatric or adult OCD to date, there is some work on riluzole, memantine, ketamine, topiramate, lamotrigine, N-acetylcysteine, and D-cycloserine. SUMMARY Given the need for more efficacious treatments in OCD, and given emergent findings on the role of the glutamatergic system in this disorder, there is a need for additional pharmacotherapy trials on glutamatergic agents in OCD. Possible research designs for such trials might include stand-alone approaches, pharmacotherapy augmentation, or psychotherapy augmentation.
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61
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Tanaka K. [Role of glutamate transporters in the pathophysiology of major mental illnesses]. Nihon Yakurigaku Zasshi 2013; 142:291-6. [PMID: 24334928 DOI: 10.1254/fpj.142.291] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Möller M, Du Preez JL, Viljoen FP, Berk M, Harvey BH. N-Acetyl cysteine reverses social isolation rearing induced changes in cortico-striatal monoamines in rats. Metab Brain Dis 2013; 28:687-96. [PMID: 24000072 DOI: 10.1007/s11011-013-9433-z] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/30/2013] [Accepted: 08/22/2013] [Indexed: 12/16/2022]
Abstract
Schizophrenia is causally associated with early-life environmental stress, implicating oxidative stress in its pathophysiology. N-acetyl cysteine (NAC), a glutathione precursor and antioxidant, is emerging as a useful agent in the adjunctive treatment of schizophrenia and other psychiatric illnesses. However, its actions on brain monoamine metabolism are unknown. Social isolation rearing (SIR) in rats presents with face, predictive and construct validity for schizophrenia. This study evaluated the dose-dependent effects of NAC (50, 150 and 250 mg/kg/day × 14 days) on SIR- vs. socially reared induced changes in cortico-striatal levels of dopamine (DA), serotonin (5-HT) noradrenaline (NA) and their associated metabolites. SIR induced significant deficits in frontal cortical DA and its metabolites, 3,4-dihydroxyphenylacetic acid (Dopac) and homovanillic acid (HVA), reduced 5-HT and its metabolite, 5-hydroxyindoleacetic acid (5-HIAA), and reduced levels of the NA metabolite, 3-methoxy-4-hydroxyphenylglycol (MHPG). In addition, significant elevations in frontal cortical NA and striatal DA, Dopac, HVA, 5-HT, 5-HIAA, NA and MHPG were also observed in SIR rats. NAC at 150 and 250 mg/kg reversed all cortico-striatal DA, Dopac, HVA, 5-HT, 5-HIAA and striatal NA alterations in SIR animals, with 250 mg/kg of NAC also reversing alterations in cortico-striatal MHPG. In conclusion, SIR profoundly alters cortico-striatal DA, 5-HT and NA pathways that parallel observations in schizophrenia, while these changes are dose-dependently reversed or abrogated by sub-chronic NAC treatment. A modulatory action on cortico-striatal monoamines may explain NACs' therapeutic use in schizophrenia and possibly other psychiatric disorders, where redox dysfunction or oxidative stress is a causal factor.
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Affiliation(s)
- Marisa Möller
- Division of Pharmacology, North-West University, Potchefstroom, South Africa,
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Ghaleiha A, Entezari N, Modabbernia A, Najand B, Askari N, Tabrizi M, Ashrafi M, Hajiaghaee R, Akhondzadeh S. Memantine add-on in moderate to severe obsessive-compulsive disorder: randomized double-blind placebo-controlled study. J Psychiatr Res 2013; 47:175-80. [PMID: 23063327 DOI: 10.1016/j.jpsychires.2012.09.015] [Citation(s) in RCA: 76] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/12/2012] [Revised: 08/17/2012] [Accepted: 09/20/2012] [Indexed: 12/17/2022]
Abstract
There is a growing body of evidence for the efficacy of memantine augmentation in patients with obsessive-compulsive disorder (OCD). However, to date, no double-blind study has addressed this issue. The objective of the present randomized double-blind placebo-controlled study was to evaluate efficacy and tolerability of memantine add-on treatment in patients with moderate to severe OCD. Forty-two patients with the diagnosis of OCD based on DSM-IV-TR who had a Yale-Brown Obsessive Compulsive Scale (Y-BOCS) score of ≥21 were randomly assigned to memantine (10 mg/day for the first week, and 20 mg/day for the rest of the trial) or placebo in addition to fluvoxamine for eight weeks. Patients were assessed using Y-BOCS every two weeks. Thirty-eight patients completed the study. Repeated measure ANOVA showed significant effect for time × treatment interaction in total scale [F (2.096, 75.470) = 5.280, P = 0.006] and obsession [F (2.340, 94.547) = 5.716, P = 0.002] and near significant effect for compulsion subscales [F (2.005, 79.179) = 2.841, P = 0.065]. By week eight, all patients in the memantine group and six (32%) patients in the placebo group [P value of Fisher's exact test <0.001] met the criteria for partial and complete response. At the end of the trial, 17 (89%) patients in the memantine group compared with six (32%) patients in the placebo group achieved remission (χ(2)(1) = 13.328, P < 0.001). Frequency of side-effects was not significantly different between the two groups. In summary, we showed that memantine add-on to fluvoxamine significantly improved short-term outcomes in patients with moderate to severe OCD.
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Affiliation(s)
- Ali Ghaleiha
- Research Center for Behavioral Disorders and Substance Abuse, Hamadan University of Medical Sciences, Hamadan, Iran
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Brennan BP, Rauch SL, Jensen JE, Pope HG. A critical review of magnetic resonance spectroscopy studies of obsessive-compulsive disorder. Biol Psychiatry 2013; 73:24-31. [PMID: 22831979 PMCID: PMC3504626 DOI: 10.1016/j.biopsych.2012.06.023] [Citation(s) in RCA: 94] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/05/2012] [Revised: 06/22/2012] [Accepted: 06/22/2012] [Indexed: 01/07/2023]
Abstract
Functional neuroimaging studies have converged to suggest that cortico-striatal-thalamo-cortical (CSTC) circuit dysfunction is a core pathophysiologic feature of obsessive-compulsive disorder (OCD). Now, complementary approaches examining regional neurochemistry are beginning to yield additional insights with regard to the neurobiology of aberrant CSTC circuitry in OCD. In particular, proton magnetic resonance spectroscopy, which allows for the in vivo quantification of various neurochemicals in the CSTC circuit and other brain regions, has recently been used extensively in studies of OCD patients. In this review, we summarize the diverse and often seemingly inconsistent findings of these studies, consider methodological factors that might help to explain these inconsistencies, and discuss several convergent findings that tentatively seem to be emerging. We conclude with suggestions for possible future proton magnetic resonance spectroscopy studies in OCD.
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Affiliation(s)
- Brian P Brennan
- Biological Psychiatry Laboratory, McLean Hospital, 115 Mill Street, Belmont, MA 02478, USA.
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Welkenhuysen M, Gligorijevic I, Ameye L, Prodanov D, Van Huffel S, Nuttin B. Neuronal activity in the bed nucleus of the stria terminalis in a rat model for obsessive-compulsive disorder. Behav Brain Res 2012. [PMID: 23195114 DOI: 10.1016/j.bbr.2012.11.019] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
In search of a new potential target for deep brain stimulation in patients with obsessive-compulsive disorder (OCD), we evaluated the single-cell activity of neurons in the bed nucleus of the stria terminalis (BST) in urethane-anesthetized rats in an animal model for OCD, the schedule-induced polydipsia (SIP) model, and compared this to the BST activity in control rats and to a third group of rats which were introduced in the model but did not develop the SIP, and thus were considered resistant. We compared the firing rate and firing pattern of BST neurons between these groups, between hemispheres and made a correlation of the firing rate and firing pattern to the position in the BST. The variability of BST neurons in SIP rats was lower and the randomness higher than BST neurons in control rats or resistant rats. The firing rate of BST neurons in SIP rats was significantly higher and the burst index lower than BST neurons in resistant rats but not in control rats. Also, neurons from the right hemisphere in the SIP group had a higher burst index than neurons from the left hemisphere. However, this is opposite in the resistant and control group. Third, we found a higher bursting index with increasing (more ventral) depth of recording. These findings suggest that schedule-induced polydipsia, which models compulsive behavior in humans, induces a change in firing behavior of BST neurons.
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Affiliation(s)
- Marleen Welkenhuysen
- Laboratory of Experimental Functional Neurosurgery, Department of Neurosciences, K.U. Leuven, Provisorium II, Minderbroedersstraat 19 Box 1033, 3000 Leuven, Belgium.
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66
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Real E, Gratacòs M, Labad J, Alonso P, Escaramís G, Segalàs C, Subirà M, López-Solà C, Estivill X, Menchón JM. Interaction of SLC1A1 gene variants and life stress on pharmacological resistance in obsessive-compulsive disorder. THE PHARMACOGENOMICS JOURNAL 2012; 13:470-5. [PMID: 22776887 DOI: 10.1038/tpj.2012.30] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/10/2012] [Revised: 05/07/2012] [Accepted: 05/23/2012] [Indexed: 11/09/2022]
Abstract
Genetic and environmental factors seem to interact and influence both the onset and the course of obsessive-compulsive disorder (OCD), but the role of glutamate transporter variants (SLC1A1) in pharmacological resistance is not known. We aimed to assess whether genetic variants in SLC1A1 and life stress at onset of the disorder interact and modulate pharmacological resistance in OCD. A single-marker association study of several single-nucleotide polymorphisms in the SLC1A1 genomic region was performed in a sample of 238 OCD patients. For the most strongly associated SNP (rs3087879), one copy of the risk allele increased the probability of higher treatment resistance (odds ratio=2.42; 95% confidence interval=1.39-4.21; P=0.0018), but only in OCD patients without life stress at onset of the disorder. These results suggest a gene-by-environment interaction effect on treatment resistance in OCD and strengthen the existing evidence of the role of the glutamatergic system in the phenomenology of OCD.
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Affiliation(s)
- E Real
- 1] Neuroscience Group-IDIBELL (Institut d'Investigació Biomèdica de Bellvitge), CIBERSAM (Centro de Investigación en Red de Salud Mental-Instituto de Salud Carlos III), L'Hospitalet de Llobregat, Barcelona, Spain [2] OCD Clinical and Research Unit, Department of Psychiatry, Bellvitge Hospital, Feixa Llarga s/n, L'Hospitalet de Llobregat, Barcelona, Spain
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67
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Alonso P, Gratacós M, Segalàs C, Escaramís G, Real E, Bayés M, Labad J, López-Solà C, Estivill X, Menchón JM. Association between the NMDA glutamate receptor GRIN2B gene and obsessive-compulsive disorder. J Psychiatry Neurosci 2012; 37:273-81. [PMID: 22433450 PMCID: PMC3380099 DOI: 10.1503/jpn.110109] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/17/2011] [Revised: 11/14/2011] [Accepted: 12/20/2011] [Indexed: 11/01/2022] Open
Abstract
BACKGROUND Recent data from neuroimaging, genetic and clinical trials and animal models suggest a role for altered glutamatergic neuro transmission in the pathogenesis of obsessive-compulsive disorder (OCD). The aim of this study was to investigate whether variants in the GRIN2B gene, the gene encoding the NR2 subunit of the N-methyl-D-aspartate (NMDA) glutamate receptor, may contribute to genetic susceptibility to OCD or to different OCD subphenotypes. METHODS Between 2003 and 2008, we performed a case-control association study in which we genotyped 10 tag single-nucleotide polymorphisms (SNPs) in the 3' untranslated region (3' UTR) of GRIN2B. We performed SNP association and haplotype analysis considering the OCD diagnosis and different OCD subphenotypes: early-onset OCD, comorbid tic disorders and OCD clinical symptom dimensions. RESULTS We enrolled 225 patients with OCD and 279 controls recruited from the OCD Clinic at Bellvitge Hospital (Barcelona, Spain). No significant difference in the distribution of alleles or genotypes was detected between patients with OCD and controls. Nonetheless, on analyzing OCD subphenotypes, the rs1805476 SNP in male patients (95% confidence interval [CI] 1.37-4.22, p = 0.002) and a 4-SNP haplotype in the whole sample (rs1805476, rs1805501, rs1805502 and rs1805477; odds ratio 1.92, 95% CI 1.22-3.01; permutation p = 0.023) were significantly associated with the presence of contamination obsessions and cleaning compulsions. LIMITATIONS Study limitations included the risk of population stratification associated with the case-control design, use of psychiatrically unscreened blood donors as the control group, reduced sample size of participants with certain OCD subphenotypes and tested polymorphisms limited to 3' UTR and exon 13 of GRIN2B. CONCLUSION Our results converge with recent data suggesting a possible contribution of glutamatergic variants to the genetic vulnerability to OCD or at least to certain OCD manifestations. The dissection of OCD into more homogeneous subphenotypes may constitute a useful tool to disentangle the complex genetic basis of the disorder.
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Affiliation(s)
- Pino Alonso
- OCD Clinical and Research Unit, Psychiatry Department, Hospital Universitari de Bellvitge, Barcelona, Spain.
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68
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Wu PL, Lane HY, Tang HS, Tsai GE. Glutamate theory in developing novel pharmacotherapies for obsessive compulsive disorder: Focusing on N-methyl-D-aspartate signaling. Biomedicine (Taipei) 2012. [DOI: 10.1016/j.biomed.2012.04.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022] Open
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69
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Decision time and perseveration of adolescent rats in the T-maze are affected differentially by buspirone and independent of 5-HT-1A expression. Pharmacol Biochem Behav 2012; 102:58-63. [PMID: 22494991 DOI: 10.1016/j.pbb.2012.03.024] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/21/2011] [Revised: 03/19/2012] [Accepted: 03/25/2012] [Indexed: 12/22/2022]
Abstract
Disruption of spontaneous alternation behavior (SAB) by the serotonin 1A (5-HT-1A) receptor agonist, 8-hydroxy-dipropylaminotetraline (8-OH-DPAT), results in repetitive behaviors that have been used to model the perseveration and indecisiveness of human obsessive-compulsive disorder (OCD). In the present study, we compared the effects of buspirone to those of 8-OH-DPAT in two strains of adolescent rats and analyzed repetitive choices of arms of the maze and prolonged apparent decision time due to induction of vicarious trial and error (VTE) behavior. In adolescent Sprague-Dawley (SD) rats, 8-OH-DPAT induced repetitive choices of arms of the maze (perseveration) and increased the apparent decision time. Buspirone induced VTE behavior and increased apparent decision time without perseveration. This distinct effect of buspirone was seen in SD adolescents but not in Long-Evans (LE) adolescents which appeared to be insensitive to buspirone. Lack of responsiveness to buspirone was dependent on the developmental stage because buspirone induced VTE behavior and prolonged decision time in LE adults. Western blotting of brain 5-HT-1A receptors showed expression of receptor protein in adolescent LE brain was comparable to that of adolescent SD and adult LE. The 5-HT-1A antagonist WAY 100365 blocked the effect 8-OH-DPAT on repetitive choice of arms but not the effect of buspirone on VTE behavior. We conclude that the adolescent LE rat has normal levels of 5-HT-1A receptor and that the effect of buspirone on VTE behavior is not mediated by the 5-HT-1A receptor. The LE strain may provide a useful system for further study of the adolescent brain and potential genetic differences in induction of repetitive behaviors.
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Proenca CC, Gao KP, Shmelkov SV, Rafii S, Lee FS. Slitrks as emerging candidate genes involved in neuropsychiatric disorders. Trends Neurosci 2012; 34:143-53. [PMID: 21315458 DOI: 10.1016/j.tins.2011.01.001] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2010] [Revised: 01/09/2011] [Accepted: 01/10/2011] [Indexed: 02/06/2023]
Abstract
Slitrks are a family of structurally related transmembrane proteins belonging to the leucine-rich repeat (LRR) superfamily. Six family members exist (Slitrk1-6) and all are highly expressed in the central nervous system (CNS). Slitrks have been implicated in mediating basic neuronal processes, ranging from neurite outgrowth and dendritic elaboration to neuronal survival. Recent studies in humans and genetic mouse models have led to the identification of Slitrks as candidate genes that might be involved in the development of neuropsychiatric conditions, such as obsessive compulsive spectrum disorders and schizophrenia. Although these system-level approaches have suggested that Slitrks play prominent roles in CNS development, key questions remain regarding the molecular mechanisms through which they mediate neuronal signaling and connectivity.
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Affiliation(s)
- Catia C Proenca
- Department of Psychiatry, Weill Cornell Medical College of Cornell University, New York, NY 10065, USA.
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71
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Wu K, Hanna GL, Rosenberg DR, Arnold PD. The role of glutamate signaling in the pathogenesis and treatment of obsessive-compulsive disorder. Pharmacol Biochem Behav 2011; 100:726-35. [PMID: 22024159 DOI: 10.1016/j.pbb.2011.10.007] [Citation(s) in RCA: 141] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/28/2011] [Revised: 09/23/2011] [Accepted: 10/03/2011] [Indexed: 01/16/2023]
Abstract
Obsessive-compulsive disorder (OCD) is a common and often debilitating neuropsychiatric condition characterized by persistent intrusive thoughts (obsessions), repetitive ritualistic behaviors (compulsions) and excessive anxiety. While the neurobiology and etiology of OCD has not been fully elucidated, there is growing evidence that disrupted neurotransmission of glutamate within corticalstriatal-thalamocortical (CSTC) circuitry plays a role in OCD pathogenesis. This review summarizes the findings from neuroimaging, animal model, candidate gene and treatment studies in the context of glutamate signaling dysfunction in OCD. First, studies using magnetic resonance spectroscopy are reviewed demonstrating altered glutamate concentrations in the caudate and anterior cingulate cortex of patients with OCD. Second, knockout mouse models, particularly the DLGAP3 and Sltrk5 knockout mouse models, display remarkably similar phenotypes of compulsive grooming behavior associated with glutamate signaling dysfunction. Third, candidate gene studies have identified associations between variants in glutamate system genes and OCD, particularly for SLC1A1 which has been shown to be associated with OCD in five independent studies. This converging evidence for a role of glutamate in OCD has led to the development of novel treatment strategies involving glutamatergic compounds, particularly riluzole and memantine. We conclude the review by outlining a glutamate hypothesis for OCD, which we hope will inform further research into etiology and treatment for this severe neuropsychiatric condition.
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Affiliation(s)
- Ke Wu
- Program in Genetics and Genomic Biology, Hospital for Sick Children, Toronto, ON, Canada M5G 1X8
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72
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Glutamate abnormalities in obsessive compulsive disorder: neurobiology, pathophysiology, and treatment. Pharmacol Ther 2011; 132:314-32. [PMID: 21963369 DOI: 10.1016/j.pharmthera.2011.09.006] [Citation(s) in RCA: 222] [Impact Index Per Article: 17.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2011] [Accepted: 08/29/2011] [Indexed: 11/22/2022]
Abstract
Obsessive compulsive disorder is prevalent, disabling, incompletely understood, and often resistant to current therapies. Established treatments consist of specialized cognitive-behavioral psychotherapy and pharmacotherapy with medications targeting serotonergic and dopaminergic neurotransmission. However, remission is rare, and more than a quarter of OCD sufferers receive little or no benefit from these approaches, even when they are optimally delivered. New insights into the disorder, and new treatment strategies, are urgently needed. Recent evidence suggests that the ubiquitous excitatory neurotransmitter glutamate is dysregulated in OCD, and that this dysregulation may contribute to the pathophysiology of the disorder. Here we review the current state of this evidence, including neuroimaging studies, genetics, neurochemical investigations, and insights from animal models. Finally, we review recent findings from small clinical trials of glutamate-modulating medications in treatment-refractory OCD. The precise role of glutamate dysregulation in OCD remains unclear, and we lack blinded, well-controlled studies demonstrating therapeutic benefit from glutamate-modulating agents. Nevertheless, the evidence supporting some important perturbation of glutamate in the disorder is increasingly strong. This new perspective on the pathophysiology of OCD, which complements the older focus on monoaminergic neurotransmission, constitutes an important focus of current research and a promising area for the ongoing development of new therapeutics.
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73
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Glutamate, obsessive-compulsive disorder, schizophrenia, and the stability of cortical attractor neuronal networks. Pharmacol Biochem Behav 2011; 100:736-51. [PMID: 21704646 DOI: 10.1016/j.pbb.2011.06.017] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/22/2010] [Revised: 05/25/2011] [Accepted: 06/09/2011] [Indexed: 12/31/2022]
Abstract
A computational neuroscience approach to the symptoms of obsessive-compulsive disorder based on a stochastic neurodynamical framework is described. An increased depth in the basins of attraction of attractor neuronal network states in the brain makes each state too stable, so that it tends to remain locked in that state, and cannot easily be moved on to another state. It is suggested that the different symptoms that may be present in obsessive--compulsive disorder could be related to changes of this type in different brain regions. In integrate-and-fire network simulations, an increase in the NMDA and/or AMPA receptor conductances, which increases the depth of the attractor basins, increases the stability of attractor networks, and makes them less easily moved on to another state by a new stimulus. Increasing GABA-receptor activated currents can partly reverse this overstability. There is now some evidence for overactivity in glutamate transmitter systems in obsessive-compulsive disorder, and the hypothesis presented here shows how some of the symptoms of obsessive-compulsive disorder could be produced by the increase in the stability of attractor networks that is produced by increased glutamatergic activity. In schizophrenia, a reduction of the firing rates of cortical neurons caused for example by reduced NMDA receptor function, present in schizophrenia, can lead to instability of the high firing rate attractor states that normally implement short-term memory and attention, contributing to the cognitive and negative symptoms of schizophrenia. Reduced cortical inhibition caused by a reduction of GABA neurotransmission, present in schizophrenia, can lead to instability of the spontaneous firing states of cortical networks, leading to a noise-induced jump to a high firing rate attractor state even in the absence of external inputs, contributing to the positive symptoms of schizophrenia.
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Abstract
BACKGROUND Several lines of evidence implicate glutamatergic neurotransmission in the pathophysiology of obsessive compulsive disorder (OCD). Sarcosine is an endogenous antagonist of glycine transporter-1. By blocking glycine uptake, sarcosine may increase the availability of synaptic glycine and enhance N-methyl-d-aspartate (NMDA) subtype glutamatergic neurotransmission. In this 10-week open-label trial, we examined the potential benefit of sarcosine treatment in OCD patients. METHOD Twenty-six outpatients with OCD and baseline Yale-Brown Obsessive Compulsive Scale (YBOCS) scores higher than 16 were enrolled. Drug-naive subjects (group 1, n = 8) and those who had discontinued serotonin reuptake inhibitors for at least 8 weeks at study entry (group 2, n = 6) received sarcosine monotherapy. The other subjects (group 3, n = 12) received sarcosine as adjunctive treatment. A flexible dosage schedule of sarcosine 500 to 2000 mg/d was applied. The primary outcome measures were Y-BOCS and Hamilton Anxiety Inventory, rated at weeks 0, 2, 4, 6, 8, and 10. Results were analyzed by repeated-measures analysis of variance. RESULTS Data of 25 subjects were eligible for analysis. The mean ± SD Y-BOCS scores decreased from 27.6 ± 5.8 to 22.7 ± 8.7, indicating a mean decrease of 19.8% ± 21.7% (P = 0.0035). Eight (32%) subjects were regarded as responders with greater than 35% reduction of Y-BOCS scores. Five of the responders achieved the good response early by week 4. Although not statistically significant, drug-naive (group 1) subjects had more profound and sustained improvement and more responders than the subjects who had received treatment before (groups 2 and 3). Sarcosine was tolerated well; only one subject withdrew owing to transient headache. CONCLUSION Sarcosine treatment can achieve a fast therapeutic effect in some OCD patients, particularly those who are treatment naive. The study supports the glycine transporter-1 as a novel target for developing new OCD treatment. Large-series placebo-controlled, double-blind studies are recommended.
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Ting JT, Feng G. Neurobiology of obsessive-compulsive disorder: insights into neural circuitry dysfunction through mouse genetics. Curr Opin Neurobiol 2011; 21:842-8. [PMID: 21605970 DOI: 10.1016/j.conb.2011.04.010] [Citation(s) in RCA: 91] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2011] [Revised: 04/11/2011] [Accepted: 04/26/2011] [Indexed: 02/07/2023]
Abstract
The precise causal factors for obsessive-compulsive disorder (OCD) are not known, although, decades of research have honed in on the cortico-striatal-thalamo-cortical (CSTC) circuitry in the brain as a critical pathway involved in obsessions and the intimately linked compulsive-repetitive behaviors. Recent progress in human and mouse genetics have led to the identification of novel candidate susceptibility genes, which in turn have facilitated a more focused approach to unraveling the nature of circuitry dysfunction in OCD. The ability to perform invasive techniques in genetic animal models of OCD will be crucial for rapid advances in this field, and as such we review the most recent developments and highlight the importance of searching out common circuitry defects underlying compulsive-repetitive behaviors.
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Affiliation(s)
- Jonathan T Ting
- Department of Neurobiology, Duke University Medical Center, Durham, NC 27710, USA
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76
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Robertson HR, Feng G. Annual Research Review: Transgenic mouse models of childhood-onset psychiatric disorders. J Child Psychol Psychiatry 2011; 52:442-75. [PMID: 21309772 PMCID: PMC3075087 DOI: 10.1111/j.1469-7610.2011.02380.x] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Childhood-onset psychiatric disorders, such as attention deficit hyperactivity disorder (ADHD), autism spectrum disorder (ASD), mood disorders, obsessive compulsive spectrum disorders (OCSD), and schizophrenia (SZ), affect many school-age children, leading to a lower quality of life, including difficulties in school and personal relationships that persist into adulthood. Currently, the causes of these psychiatric disorders are poorly understood, resulting in difficulty diagnosing affected children, and insufficient treatment options. Family and twin studies implicate a genetic contribution for ADHD, ASD, mood disorders, OCSD, and SZ. Identification of candidate genes and chromosomal regions associated with a particular disorder provide targets for directed research, and understanding how these genes influence the disease state will provide valuable insights for improving the diagnosis and treatment of children with psychiatric disorders. Transgenic mouse models are one important approach in the study of human diseases, allowing for the use of a variety of experimental approaches to dissect the contribution of a specific chromosomal or genetic abnormality in human disorders. While it is impossible to model an entire psychiatric disorder in a single mouse model, these models can be extremely valuable in dissecting out the specific role of a gene, pathway, neuron subtype, or brain region in a particular abnormal behavior. In this review we discuss existing transgenic mouse models for childhood-onset psychiatric disorders. We compare the strength and weakness of various transgenic mouse models proposed for each of the common childhood-onset psychiatric disorders, and discuss future directions for the study of these disorders using cutting-edge genetic tools.
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Affiliation(s)
- Holly R. Robertson
- Duke University, Neurobiology Department Durham, N.C.,Massachusetts Institute of Technology, Brain and Cognitive Sciences Department Cambridge, M.A
| | - Guoping Feng
- Duke University, Neurobiology Department Durham, N.C.,Massachusetts Institute of Technology, Brain and Cognitive Sciences Department Cambridge, M.A
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Gomes FV, Casarotto PC, Resstel LBM, Guimarães FS. Facilitation of CB1 receptor-mediated neurotransmission decreases marble burying behavior in mice. Prog Neuropsychopharmacol Biol Psychiatry 2011; 35:434-8. [PMID: 21111767 DOI: 10.1016/j.pnpbp.2010.11.027] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/25/2010] [Revised: 11/02/2010] [Accepted: 11/18/2010] [Indexed: 10/18/2022]
Abstract
Obsessive-compulsive disorder (OCD) is a common psychiatric disorder characterized by the occurrence of obsessions and compulsions. Glutamatergic abnormalities have been related to the pathophysiology of OCD. Cannabinoids inhibit glutamate release in the central nervous system, but the involvement of drugs targeting the endocannabinoid system has not yet been tested in animal models of repetitive behavior. Thus, the aim of the present study was to verify the effects of the CB1 receptor agonist WIN55,212-2, the inhibitor of anandamide uptake AM404 and the anandamide hydrolysis inhibitor URB597, on compulsive-associate behavior in male C57BL/6J mice submitted to the marble burying test (MBT), an animal model used for anti-compulsive drug screening. WIN55,212-2 (1 and 3 mg/kg), AM404 (1 and 3 mg/kg) and URB597 (0.1, 0.3 and 1 mg/kg) induced a significant decrease in the number of buried marbles compared to controls. Pretreatment with the CB1 receptor antagonist, AM251, prevented both WIN55,212-2 and URB597 effects. These results suggest a potential role for drugs acting on the cannabinoid system in modulating compulsive behavior.
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Affiliation(s)
- Felipe V Gomes
- Department of Pharmacology, School of Medicine of Ribeirão Preto, University of São Paulo, Bandeirantes Avenue 3900, Ribeirão Preto, SP, 14049-900, Brazil
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