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Torres-Carmona E, Nakajima S, Iwata Y, Ueno F, Stefan C, Song J, Abdolizadeh A, Koizumi MT, Kambari Y, Amaev A, Agarwal SM, Mar W, de Luca V, Remington G, Gerretsen P, Graff-Guerrero A. Clozapine treatment and astrocyte activity in treatment resistant schizophrenia: A proton magnetic resonance spectroscopy study. Schizophr Res 2024; 270:152-161. [PMID: 38909486 DOI: 10.1016/j.schres.2024.06.020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/20/2023] [Revised: 04/17/2024] [Accepted: 06/15/2024] [Indexed: 06/25/2024]
Abstract
Clozapine is the only antipsychotic approved for treating treatment-resistant schizophrenia (TRS), characterized by persistent positive symptoms despite adequate antipsychotic treatment. Unfortunately, clozapine demonstrates clinical efficacy in only ~30-60 % of patients with TRS (clozapine-responders; ClzR+), while the remaining ~40-70 % are left with no pharmacological recourse for improvement (clozapine-resistant; ClzR-). Mechanism(s) underlying clozapine's superior efficacy remain unclear. However, in vitro evidence suggests clozapine may mitigate glutamatergic dysregulations observed in TRS, by modulating astrocyte activity in ClzR+, but not ClzR-. A factor that if proven correct, may help the assessment of treatment response and development of more effective antipsychotics. To explore the presence of clozapine-astrocyte interaction and clinical improvement, we used 3 T proton-magnetic resonance spectroscopy to quantify levels of myo-Inositol, surrogate biomarker of astrocyte activity, in regions related to schizophrenia neurobiology: Dorsal-anterior-cingulate-cortex (dACC), left-dorsolateral-prefrontal-cortex (left-DLPFC), and left-striatum (left-striatum) of 157 participants (ClzR- = 30; ClzR+ = 37; responders = 38; controls = 52). Clozapine treatment was assessed using clozapine to norclozapine plasma levels, 11-12 h after last clozapine dose. Measures for symptom severity (i.e., Positive and Negative Symptoms Scale) and cognition (i.e., Mini-Mental State Examination) were also recorded. Higher levels of myo-Inositol were observed in TRS groups versus responders and controls (dACC (p < 0.001); left-striatum (p = 0.036); left-DLPFC (p = 0.023)). In ClzR+, but not ClzR-, clozapine to norclozapine ratios were positively associated with myo-Inositol levels (dACC (p = 0.004); left-DLPFC (p < 0.001)), and lower positive symptom severity (p < 0.001). Our results support growing in vitro evidence of clozapine-astrocyte interaction in clozapine-responders. Further research may determine the viability of clozapine-astrocyte interactions as an early marker of clozapine response.
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Affiliation(s)
- Edgardo Torres-Carmona
- Centre for Addiction and Mental Health (CAMH), Toronto, ON, Canada; Institute of Medical Sciences, University of Toronto, Toronto, ON, Canada
| | - Shinichiro Nakajima
- Centre for Addiction and Mental Health (CAMH), Toronto, ON, Canada; Department of Neuropsychiatry, Keio University, Minato, Tokyo, Japan
| | - Yusuke Iwata
- Centre for Addiction and Mental Health (CAMH), Toronto, ON, Canada
| | - Fumihiko Ueno
- Centre for Addiction and Mental Health (CAMH), Toronto, ON, Canada; Department of Psychiatry, University of Toronto, Toronto, ON, Canada
| | - Cristiana Stefan
- Centre for Addiction and Mental Health (CAMH), Toronto, ON, Canada
| | - Jianmeng Song
- Centre for Addiction and Mental Health (CAMH), Toronto, ON, Canada; Institute of Medical Sciences, University of Toronto, Toronto, ON, Canada
| | - Ali Abdolizadeh
- Centre for Addiction and Mental Health (CAMH), Toronto, ON, Canada; Institute of Medical Sciences, University of Toronto, Toronto, ON, Canada
| | | | - Yasaman Kambari
- Centre for Addiction and Mental Health (CAMH), Toronto, ON, Canada; Institute of Medical Sciences, University of Toronto, Toronto, ON, Canada
| | - Aron Amaev
- Centre for Addiction and Mental Health (CAMH), Toronto, ON, Canada; Institute of Medical Sciences, University of Toronto, Toronto, ON, Canada
| | - Sri Mahavir Agarwal
- Centre for Addiction and Mental Health (CAMH), Toronto, ON, Canada; Department of Psychiatry, University of Toronto, Toronto, ON, Canada; Campbell Family Mental Health Research Institute, CAMH, Toronto, ON, Canada
| | - Wanna Mar
- Centre for Addiction and Mental Health (CAMH), Toronto, ON, Canada
| | - Vincenzo de Luca
- Centre for Addiction and Mental Health (CAMH), Toronto, ON, Canada; Department of Psychiatry, University of Toronto, Toronto, ON, Canada; Campbell Family Mental Health Research Institute, CAMH, Toronto, ON, Canada
| | - Gary Remington
- Centre for Addiction and Mental Health (CAMH), Toronto, ON, Canada; Department of Psychiatry, University of Toronto, Toronto, ON, Canada; Campbell Family Mental Health Research Institute, CAMH, Toronto, ON, Canada
| | - Philip Gerretsen
- Centre for Addiction and Mental Health (CAMH), Toronto, ON, Canada; Department of Psychiatry, University of Toronto, Toronto, ON, Canada; Campbell Family Mental Health Research Institute, CAMH, Toronto, ON, Canada
| | - Ariel Graff-Guerrero
- Centre for Addiction and Mental Health (CAMH), Toronto, ON, Canada; Department of Psychiatry, University of Toronto, Toronto, ON, Canada; Campbell Family Mental Health Research Institute, CAMH, Toronto, ON, Canada.
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Yu ZX, Pi Y, Chen MK, Dong DJ, Gu Q. Clozapine-Induced Severe Toxicity: Exploring the Pharmacokinetic Profile of Clozapine and Its Significance in Hemodynamic Instability - A Case Report. Int Med Case Rep J 2024; 17:111-120. [PMID: 38348428 PMCID: PMC10860498 DOI: 10.2147/imcrj.s444685] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2023] [Accepted: 02/01/2024] [Indexed: 02/15/2024] Open
Abstract
Hemodynamic instability in patients with clozapine intoxication can indirectly reflect the serum concentration of clozapine.We have described a case of a 32-year-old pregnant woman who developed life-threatening clozapine toxicity at 28 weeks of gestation. The levels of clozapine and norclozapine in the serum were high. We initiated hemoperfusion(HP) and other detoxification therapies to remove the drug. The patient had severely dilated peripheral blood vessels, which led to cardiac symptoms such as fatal hypotension and uncontrollable tachycardia, resulting in very high cardiac output and elevated Central venous oxygen saturation (ScvO2). Pharmacological intervention significantly improved the hemodynamics.In light of our observations in the ongoing case, we posit that evaluating hemodynamic parameters before and after blood detoxification could serve as a valuable means to gauge effectiveness and provide guidance for treatment.
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Affiliation(s)
- Zhu-Xi Yu
- Department of Critical Care Medicine, the Affiliated Drum Tower Hospital of Nanjing University Medical School, Nanjing, Jiangsu, 21008, People’s Republic of China
| | - Yang Pi
- Department of Critical Care Medicine, the Affiliated Drum Tower Hospital of Nanjing University Medical School, Nanjing, Jiangsu, 21008, People’s Republic of China
| | - Mei-Kai Chen
- Department of Critical Care Medicine, the Affiliated Drum Tower Hospital of Nanjing University Medical School, Nanjing, Jiangsu, 21008, People’s Republic of China
| | - Dan-Jiang Dong
- Department of Critical Care Medicine, the Affiliated Drum Tower Hospital of Nanjing University Medical School, Nanjing, Jiangsu, 21008, People’s Republic of China
| | - Qin Gu
- Department of Critical Care Medicine, the Affiliated Drum Tower Hospital of Nanjing University Medical School, Nanjing, Jiangsu, 21008, People’s Republic of China
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Pang TSW, Chun JSW, Wong TY, Chu ST, Ma CF, Honer WG, Chan SKW. A systematic review of neuroimaging studies of clozapine-resistant schizophrenia. SCHIZOPHRENIA (HEIDELBERG, GERMANY) 2023; 9:65. [PMID: 37752161 PMCID: PMC10522657 DOI: 10.1038/s41537-023-00392-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/01/2023] [Accepted: 09/08/2023] [Indexed: 09/28/2023]
Abstract
This systematic review aimed to review neuroimaging studies comparing clozapine-resistant schizophrenia patients with clozapine-responding patients, and with first-line antipsychotic responding (FLR) patients. A total of 19 studies including 6 longitudinal studies were identified. Imaging techniques comprised computerized tomography (CT, n = 3), structural magnetic resonance imaging (MRI, n = 7), magnetic resonance spectroscopy (MRS, n = 5), functional MRI (n = 1), single-photon emission computerized tomography (SPECT, n = 3) and diffusion tensor imaging (DTI, n = 1). The most consistent finding was hypo-frontality in the clozapine-resistant group compared with the clozapine-responding group with possible differences in frontal-striatal-basal ganglia circuitry as well as the GABA level between the two treatment-resistant groups. Additional statistically significant findings were reported when comparing clozapine-resistant patients with the FLR group, including lower cortical thickness and brain volume of multiple brain regions as well as lower Glx/Cr level in the dorsolateral prefrontal cortex. Both treatment-resistant groups were found to have extensive differences in neurobiological features in comparison with the FLR group. Overall results suggested treatment-resistant schizophrenia is likely to be a neurobiological distinct type of the illness. Clozapine-resistant and clozapine-responding schizophrenia are likely to have both shared and distinct neurobiological features. However, conclusions from existing studies are limited, and future multi-center collaborative studies are required with a consensus clinical definition of patient samples, multimodal imaging tools, and longitudinal study designs.
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Affiliation(s)
- Tiffanie Sze Wing Pang
- Department of Psychiatry, School of Clinical Medicine, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong SAR, China
| | - Johnny Siu Wah Chun
- Department of Psychiatry, School of Clinical Medicine, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong SAR, China
| | - Ting Yat Wong
- Department of Psychology, The Education University of Hong Kong, Hong Kong SAR, China
| | - Sin Ting Chu
- Department of Psychiatry, School of Clinical Medicine, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong SAR, China
| | - Chak Fai Ma
- Department of Psychiatry, School of Clinical Medicine, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong SAR, China
- School of Nursing, The Hong Kong Polytechnic University, Hong Kong SAR, China
| | - William G Honer
- Department of Psychiatry, The University of British Columbia, Vancouver, Canada
| | - Sherry Kit Wa Chan
- Department of Psychiatry, School of Clinical Medicine, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong SAR, China.
- The State Key Laboratory of Brain and Cognitive Sciences, The University of Hong Kong, HKSAR, Hong Kong SAR, China.
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de Bartolomeis A, Ciccarelli M, De Simone G, Mazza B, Barone A, Vellucci L. Canonical and Non-Canonical Antipsychotics' Dopamine-Related Mechanisms of Present and Next Generation Molecules: A Systematic Review on Translational Highlights for Treatment Response and Treatment-Resistant Schizophrenia. Int J Mol Sci 2023; 24:ijms24065945. [PMID: 36983018 PMCID: PMC10051989 DOI: 10.3390/ijms24065945] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2023] [Revised: 03/15/2023] [Accepted: 03/17/2023] [Indexed: 03/30/2023] Open
Abstract
Schizophrenia is a severe psychiatric illness affecting almost 25 million people worldwide and is conceptualized as a disorder of synaptic plasticity and brain connectivity. Antipsychotics are the primary pharmacological treatment after more than sixty years after their introduction in therapy. Two findings hold true for all presently available antipsychotics. First, all antipsychotics occupy the dopamine D2 receptor (D2R) as an antagonist or partial agonist, even if with different affinity; second, D2R occupancy is the necessary and probably the sufficient mechanism for antipsychotic effect despite the complexity of antipsychotics' receptor profile. D2R occupancy is followed by coincident or divergent intracellular mechanisms, implying the contribution of cAMP regulation, β-arrestin recruitment, and phospholipase A activation, to quote some of the mechanisms considered canonical. However, in recent years, novel mechanisms related to dopamine function beyond or together with D2R occupancy have emerged. Among these potentially non-canonical mechanisms, the role of Na2+ channels at the dopamine at the presynaptic site, dopamine transporter (DAT) involvement as the main regulator of dopamine concentration at synaptic clefts, and the putative role of antipsychotics as chaperones for intracellular D2R sequestration, should be included. These mechanisms expand the fundamental role of dopamine in schizophrenia therapy and may have relevance to considering putatively new strategies for treatment-resistant schizophrenia (TRS), an extremely severe condition epidemiologically relevant and affecting almost 30% of schizophrenia patients. Here, we performed a critical evaluation of the role of antipsychotics in synaptic plasticity, focusing on their canonical and non-canonical mechanisms of action relevant to the treatment of schizophrenia and their subsequent implication for the pathophysiology and potential therapy of TRS.
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Affiliation(s)
- Andrea de Bartolomeis
- Section of Psychiatry, Laboratory of Translational and Molecular Psychiatry and Unit of Treatment-Resistant Psychosis, Department of Neuroscience, Reproductive Sciences and Dentistry, University Medical School of Naples "Federico II", 80131 Naples, Italy
| | - Mariateresa Ciccarelli
- Section of Psychiatry, Laboratory of Translational and Molecular Psychiatry and Unit of Treatment-Resistant Psychosis, Department of Neuroscience, Reproductive Sciences and Dentistry, University Medical School of Naples "Federico II", 80131 Naples, Italy
| | - Giuseppe De Simone
- Section of Psychiatry, Laboratory of Translational and Molecular Psychiatry and Unit of Treatment-Resistant Psychosis, Department of Neuroscience, Reproductive Sciences and Dentistry, University Medical School of Naples "Federico II", 80131 Naples, Italy
| | - Benedetta Mazza
- Section of Psychiatry, Laboratory of Translational and Molecular Psychiatry and Unit of Treatment-Resistant Psychosis, Department of Neuroscience, Reproductive Sciences and Dentistry, University Medical School of Naples "Federico II", 80131 Naples, Italy
| | - Annarita Barone
- Section of Psychiatry, Laboratory of Translational and Molecular Psychiatry and Unit of Treatment-Resistant Psychosis, Department of Neuroscience, Reproductive Sciences and Dentistry, University Medical School of Naples "Federico II", 80131 Naples, Italy
| | - Licia Vellucci
- Section of Psychiatry, Laboratory of Translational and Molecular Psychiatry and Unit of Treatment-Resistant Psychosis, Department of Neuroscience, Reproductive Sciences and Dentistry, University Medical School of Naples "Federico II", 80131 Naples, Italy
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5
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Qubad M, Bittner RA. Second to none: rationale, timing, and clinical management of clozapine use in schizophrenia. Ther Adv Psychopharmacol 2023; 13:20451253231158152. [PMID: 36994117 PMCID: PMC10041648 DOI: 10.1177/20451253231158152] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/16/2022] [Accepted: 01/24/2023] [Indexed: 03/31/2023] Open
Abstract
Despite its enduring relevance as the single most effective and important evidence-based treatment for schizophrenia, underutilization of clozapine remains considerable. To a substantial degree, this is attributable to a reluctance of psychiatrists to offer clozapine due to its relatively large side-effect burden and the complexity of its use. This underscores the necessity for continued education regarding both the vital nature and the intricacies of clozapine treatment. This narrative review summarizes all clinically relevant areas of evidence, which support clozapine's wide-ranging superior efficacy - for treatment-resistant schizophrenia (TRS) and beyond - and make its safe use eminently feasible. Converging evidence indicates that TRS constitutes a distinct albeit heterogeneous subgroup of schizophrenias primarily responsive to clozapine. Most importantly, the predominantly early onset of treatment resistance and the considerable decline in response rates associated with its delayed initiation make clozapine an essential treatment option throughout the course of illness, beginning with the first psychotic episode. To maximize patients' benefits, systematic early recognition efforts based on stringent use of TRS criteria, a timely offer of clozapine, thorough side-effect screening and management as well as consistent use of therapeutic drug monitoring and established augmentation strategies for suboptimal responders are crucial. To minimize permanent all-cause discontinuation, re-challenges after neutropenia or myocarditis should be considered. Owing to clozapine's unique efficacy, comorbid conditions including substance use and most somatic disorders should not dissuade but rather encourage clinicians to consider clozapine. Moreover, treatment decisions need to be informed by the late onset of clozapine's full effects, which for reduced suicidality and mortality rates may not even be readily apparent. Overall, the singular extent of its efficacy combined with the high level of patient satisfaction continues to distinguish clozapine from all other available antipsychotics.
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Affiliation(s)
- Mishal Qubad
- Department of Psychiatry, Psychosomatic Medicine and Psychotherapy, University Hospital Frankfurt, Goethe University, Frankfurt am Main, Germany
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6
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Jiao S, Cao T, Cai H. Peripheral biomarkers of treatment-resistant schizophrenia: Genetic, inflammation and stress perspectives. Front Pharmacol 2022; 13:1005702. [PMID: 36313375 PMCID: PMC9597880 DOI: 10.3389/fphar.2022.1005702] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2022] [Accepted: 09/26/2022] [Indexed: 11/16/2022] Open
Abstract
Treatment-resistant schizophrenia (TRS) often results in severe disability and functional impairment. Currently, the diagnosis of TRS is largely exclusionary and emphasizes the improvement of symptoms that may not be detected early and treated according to TRS guideline. As the gold standard, clozapine is the most prescribed selection for TRS. Therefore, how to predict TRS in advance is critical for forming subsequent treatment strategy especially clozapine is used during the early stage of TRS. Although mounting studies have identified certain clinical factors and neuroimaging characteristics associated with treatment response in schizophrenia, the predictors for TRS remain to be explored. Biomarkers, particularly for peripheral biomarkers, show great potential in predicting TRS in view of their predictive validity, noninvasiveness, ease of testing and low cost that would enable their widespread use. Recent evidence supports that the pathogenesis of TRS may be involved in abnormal neurotransmitter systems, inflammation and stress. Due to the heterogeneity of TRS and the lack of consensus in diagnostic criteria, it is difficult to compare extensive results among different studies. Based on the reported neurobiological mechanisms that may be associated with TRS, this paper narratively reviews the updates of peripheral biomarkers of TRS, from genetic and other related perspectives. Although current evidence regarding biomarkers in TRS remains fragmentary, when taken together, it can help to better understand the neurobiological interface of clinical phenotypes and psychiatric symptoms, which will enable individualized prediction and therapy for TRS in the long run.
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Affiliation(s)
- Shimeng Jiao
- Department of Pharmacy, The Second Xiangya Hospital, Central South University, Changsha, China
- Institute of Clinical Pharmacy, Central South University, Changsha, China
- International Research Center for Precision Medicine, Transformative Technology and Software Services, Changsha, Hunan, China
| | - Ting Cao
- Department of Pharmacy, The Second Xiangya Hospital, Central South University, Changsha, China
- Institute of Clinical Pharmacy, Central South University, Changsha, China
- International Research Center for Precision Medicine, Transformative Technology and Software Services, Changsha, Hunan, China
| | - Hualin Cai
- Department of Pharmacy, The Second Xiangya Hospital, Central South University, Changsha, China
- Institute of Clinical Pharmacy, Central South University, Changsha, China
- International Research Center for Precision Medicine, Transformative Technology and Software Services, Changsha, Hunan, China
- *Correspondence: Hualin Cai,
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de Bartolomeis A, Vellucci L, Barone A, Manchia M, De Luca V, Iasevoli F, Correll CU. Clozapine's multiple cellular mechanisms: What do we know after more than fifty years? A systematic review and critical assessment of translational mechanisms relevant for innovative strategies in treatment-resistant schizophrenia. Pharmacol Ther 2022; 236:108236. [PMID: 35764175 DOI: 10.1016/j.pharmthera.2022.108236] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2022] [Revised: 06/21/2022] [Accepted: 06/21/2022] [Indexed: 12/21/2022]
Abstract
Almost fifty years after its first introduction into clinical care, clozapine remains the only evidence-based pharmacological option for treatment-resistant schizophrenia (TRS), which affects approximately 30% of patients with schizophrenia. Despite the long-time experience with clozapine, the specific mechanism of action (MOA) responsible for its superior efficacy among antipsychotics is still elusive, both at the receptor and intracellular signaling level. This systematic review is aimed at critically assessing the role and specific relevance of clozapine's multimodal actions, dissecting those mechanisms that under a translational perspective could shed light on molecular targets worth to be considered for further innovative antipsychotic development. In vivo and in vitro preclinical findings, supported by innovative techniques and methods, together with pharmacogenomic and in vivo functional studies, point to multiple and possibly overlapping MOAs. To better explore this crucial issue, the specific affinity for 5-HT2R, D1R, α2c, and muscarinic receptors, the relatively low occupancy at dopamine D2R, the interaction with receptor dimers, as well as the potential confounder effects resulting in biased ligand action, and lastly, the role of the moiety responsible for lipophilic and alkaline features of clozapine are highlighted. Finally, the role of transcription and protein changes at the synaptic level, and the possibility that clozapine can directly impact synaptic architecture are addressed. Although clozapine's exact MOAs that contribute to its unique efficacy and some of its severe adverse effects have not been fully understood, relevant information can be gleaned from recent mechanistic understandings that may help design much needed additional therapeutic strategies for TRS.
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Affiliation(s)
- Andrea de Bartolomeis
- Section of Psychiatry, Laboratory of Translational and Molecular Psychiatry and Unit of Treatment Resistant Psychosis, Department of Neuroscience, Reproductive Science and Dentistry, University Medical School of Naples "Federico II", Naples, Italy.
| | - Licia Vellucci
- Section of Psychiatry, Laboratory of Translational and Molecular Psychiatry and Unit of Treatment Resistant Psychosis, Department of Neuroscience, Reproductive Science and Dentistry, University Medical School of Naples "Federico II", Naples, Italy
| | - Annarita Barone
- Section of Psychiatry, Laboratory of Translational and Molecular Psychiatry and Unit of Treatment Resistant Psychosis, Department of Neuroscience, Reproductive Science and Dentistry, University Medical School of Naples "Federico II", Naples, Italy
| | - Mirko Manchia
- Section of Psychiatry, Department of Medical Sciences and Public Health, University of Cagliari, Cagliari, Italy; Department of Pharmacology, Dalhousie University, Halifax, Nova Scotia, Canada
| | | | - Felice Iasevoli
- Section of Psychiatry, Laboratory of Translational and Molecular Psychiatry and Unit of Treatment Resistant Psychosis, Department of Neuroscience, Reproductive Science and Dentistry, University Medical School of Naples "Federico II", Naples, Italy
| | - Christoph U Correll
- The Zucker Hillside Hospital, Department of Psychiatry, Northwell Health, Glen Oaks, NY, USA; Donald and Barbara Zucker School of Medicine at Hofstra/Northwell, Department of Psychiatry and Molecular Medicine, Hempstead, NY, USA; Charité Universitätsmedizin Berlin, Department of Child and Adolescent Psychiatry, Berlin, Germany
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Adverse Drug Reactions in Relation to Clozapine Plasma Levels: A Systematic Review. Pharmaceuticals (Basel) 2022; 15:ph15070817. [PMID: 35890117 PMCID: PMC9317288 DOI: 10.3390/ph15070817] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2022] [Revised: 06/22/2022] [Accepted: 06/27/2022] [Indexed: 11/16/2022] Open
Abstract
Clozapine is the gold standard for treatment-resistant schizophrenia. Serious and even life-threatening adverse effects, mostly granulocytopenia, myocarditis, and constipation, are of great clinical concern and constitute a barrier to prescribing clozapine, thus depriving many eligible patients of a lifesaving treatment option. Interestingly, clozapine presents variable pharmacokinetics affected by numerous parameters, leading to significant inter- and intra-individual variation. Therefore, therapeutic drug monitoring of plasma clozapine levels confers a significant benefit in everyday clinical practice by increasing the confidence of the prescribing doctor to the drug and the adherence of the patient to the treatment, mainly by ensuring effective treatment and limited dose-related side effects. In the present systematic review, we aimed at identifying how a full range of adverse effects relates to plasma clozapine levels, using the Jadad grading system for assessing the quality of the available clinical evidence. Our findings indicate that EEG slowing, obsessive-compulsive symptoms, heart rate variability, hyperinsulinemia, metabolic syndrome, and constipation correlate to plasma clozapine levels, whereas QTc, myocarditis, sudden death, leucopenia, neutropenia, sialorrhea, are rather unrelated. Rapid dose escalation at the initiation of treatment might contribute to the emergence of myocarditis, or leucopenia. Strategies for managing adverse effects are different in these conditions and are discussed accordingly.
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A preliminary genetic association study of GAD1 and GABAB receptor genes in patients with treatment-resistant schizophrenia. Mol Biol Rep 2021; 49:2015-2024. [PMID: 34845648 DOI: 10.1007/s11033-021-07019-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2021] [Accepted: 11/24/2021] [Indexed: 02/07/2023]
Abstract
BACKGROUND GABAergic system dysfunction has been implicated in the etiology of schizophrenia and of cognitive impairments in particular. Patients with treatment-resistant schizophrenia (TRS) generally suffer from profound cognitive impairments in addition to severe positive symptoms, suggesting that GABA system dysfunction could be involved more closely in patients with TRS. METHODS AND RESULTS In the present study, exome sequencing was conducted on fourteen TRS patients, whereby four SNPs were identified on GAD1, GABBR1 and GABBR2 genes. An association study for five SNPs including these 4 SNPs and rs3749034 on GAD1 as then performed among 357 patients with TRS, 682 non-TRS patients and 508 healthy controls (HC). The results revealed no significant differences in allelic and/or genetic distributions for any of the five SNPs. However, several subanalyses in comparisons between schizophrenia and HC groups, as well as between the three groups, showed nominal-level significance for rs3749034 on GAD1 and rs10985765/rs3750344 on GABBR2. In particular, in comparisons of female subjects, rigorous analysis for rs3749034 showed a statistical difference between the schizophrenia and HC groups and between the TRS and HC groups. CONCLUSIONS Several positive results in subanalyses suggested that genetic vulnerability in the GABA system to schizophrenia or TRS could be affected by sex or sampling area, and overall, that rs3749034 on GAD1 and rs10985765 on GABBR2 could be related to TRS. In the present study, only a few SNPs were examined; it is possible that other important genetic variants in other regions of GABA-related genes were not captured in this preliminary study.
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Dragoi AM, Radulescu I, Năsui BA, Pop AL, Varlas VN, Trifu S. Clozapine: An Updated Overview of Pharmacogenetic Biomarkers, Risks, and Safety-Particularities in the Context of COVID-19. Brain Sci 2020; 10:E840. [PMID: 33187329 PMCID: PMC7697202 DOI: 10.3390/brainsci10110840] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2020] [Revised: 11/06/2020] [Accepted: 11/08/2020] [Indexed: 12/11/2022] Open
Abstract
BACKGROUND clozapine (CLZ) use is precarious due to its neurological, cardiovascular, and hematological side effects; however, it is the gold standard in therapy-resistant schizophrenia (TRS) in adults and is underused. OBJECTIVE to examine the most recent CLZ data on (a) side effects concerning (b) recent pharmacological mechanisms, (c) therapy benefits, and (d) the particularities of the COVID-19 pandemic. DATA SOURCES a search was performed in two databases (PubMed and Web of Science) using the specific keywords "clozapine" and "schizophrenia", "side effects", "agranulocytosis", "TRS", or "bipolar affective disorder (BAF)" for the last ten years. STUDY ELIGIBILITY CRITERIA clinical trials on adults with acute symptoms of schizophrenia or related disorders. RESULTS we selected 37 studies, randomized controlled trials (RCTs), and clinical case series (CCS), centered on six main topics in the search area: (a) CLZ in schizophrenia, (b) CLZ in bipolar disorder, (c) side effects during the clozapine therapy, (d) CLZ in pregnancy, (e) CLZ in early-onset schizophrenia, and (f) CLZ therapy and COVID-19 infection. LIMITATIONS we considered RCTs and CCS from two databases, limited to the search topics. Conclusions and implications of key findings: (a) clozapine doses should be personalized for each patient based on pharmacogenetics testing when available; the genetic vulnerability postulates predictors of adverse reactions' severity; patients with a lower genetic risk could have less frequent hematological monitoring; (b) a CLZ-associated risk of pulmonary embolism imposes prophylactic measures for venous thromboembolism; (c) convulsive episodes are not an indication for stopping treatment; the plasma concentration of clozapine is a better side effect predictor than the dosage; (d) COVID-19 infection may enhance clozapine toxicity, generating an increased risk of pneumonia. Therapy must be continued with the proper monitoring of the white blood count, and the clozapine dose decreased by half until three days after the fever breaks; psychiatrists and healthcare providers must act together.
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Affiliation(s)
- Ana Miruna Dragoi
- Department of Psychiatry, “Alexandru Obregia” Clinical Hospital for Psychiatry, 10 Berceni St., 041914 Bucharest, Romania;
| | - Ioana Radulescu
- Department of General Medicine, “Carol Davila” University of Medicine and Pharmacy, 37 Dionisie Lupu St., 020021 Bucharest, Romania; (I.R.); (V.N.V.)
| | - Bogdana Adriana Năsui
- Department of Community Health, “Iuliu Hațieganu” University of Medicine and Pharmacy, 6 Louis Pasteur St., 400349 Cluj-Napoca, Romania; or
| | - Anca Lucia Pop
- Department of Clinical Laboratory, Food Safety, “Carol Davila” University of Medicine and Pharmacy, 6 Traian Vuia St., 020945 Bucharest, Romania
| | - Valentin Nicolae Varlas
- Department of General Medicine, “Carol Davila” University of Medicine and Pharmacy, 37 Dionisie Lupu St., 020021 Bucharest, Romania; (I.R.); (V.N.V.)
| | - Simona Trifu
- Department of Clinical Neurosciences, “Carol Davila” University of Medicine and Pharmacy, 37 Dionisie Lupu St., 020021 Bucharest, Romania;
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11
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Binding of clozapine to the GABA B receptor: clinical and structural insights. Mol Psychiatry 2020; 25:1910-1919. [PMID: 32203158 DOI: 10.1038/s41380-020-0709-5] [Citation(s) in RCA: 50] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/14/2019] [Revised: 02/18/2020] [Accepted: 03/02/2020] [Indexed: 12/30/2022]
Abstract
Clozapine is the gold-standard agent for treatment resistant schizophrenia but its mechanism of action remains unclear. There is emerging evidence of the potential role of the GABAB receptor in the pathogenesis of schizophrenia. It has been hypothesised that clozapine can mediate its actions via the GABAB receptor. Baclofen is currently recognised as the prototype GABAB receptor agonist. There are some potential clinical similarities between clozapine and baclofen. Indeed, baclofen has been previously proposed for use as an antipsychotic agent. Our analysis of the X-ray crystal structure of GABAB receptor along with molecular docking calculations, suggests that clozapine could directly bind to the GABAB receptor similar to that of baclofen. This finding could lead to a better understanding of the pharmacological uniqueness of clozapine, potential development of a biomarker for treatment resistant schizophrenia and the development of more targeted treatments leading to personalisation of treatment.
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12
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Xu SW, Dong M, Zhang Q, Yang SY, Chen LY, Sim K, He YL, Chiu HF, Sartorius N, Tan CH, Chong MY, Shinfuku N, Lin SK, Ng CH, Ungvari GS, Najoan E, Kallivayalil RA, Jamaluddin R, Javed A, Iida H, Swe T, Zhang B, Xiang YT. Clozapine prescription pattern in patients with schizophrenia in Asia: The REAP survey (2016). Psychiatry Res 2020; 287:112271. [PMID: 30885383 DOI: 10.1016/j.psychres.2019.02.056] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/28/2018] [Revised: 02/20/2019] [Accepted: 02/20/2019] [Indexed: 10/27/2022]
Abstract
Clozapine is an effective antipsychotic medication for treatment resistant schizophrenia and is widely used in Asian countries. This study investigated clozapine prescription patterns and their associated factors in Asian countries and territories based on the database of the Research on Asian Psychotropic prescription study (REAP) conducted in 2016. Demographic and clinical information of 3744 schizophrenia patients in 15 Asian countries and territories was collected with a standardized data collection form. In total, 18.4% of the sample received clozapine, ranging from 2.6% in Japan to 32.3% in Hong Kong. Binary logistic regression analysis revealed that higher antipsychotic dose (OR = 1.002, P < 0.001), less frequent first admission in the sample (OR = 0.6, P < 0.001), more severe negative symptoms (OR = 1.4, P = 0.001) and less first generation antipsychotics (FGAs) (OR = 0.2, P < 0.001) were independently and significantly associated with clozapine prescription. Clozapine is frequently and increasingly prescribed for schizophrenia in Asia, with large variation across countries and territories. Given the diverse prescription patterns of clozapine found in Asian countries/territories, the clinical rationale of clozapine prescription needs careful consideration in Asia with more local input.
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Affiliation(s)
- Shi-Wei Xu
- Department of Psychiatry and Psychology, Southern Medical University Nanfang Hospital, Guangdong, China; Guangdong-Hong Kong-Macao Greater Bay Area Center for Brain Science and Brain-Inspired Intelligence, Guangzhou, China
| | - Min Dong
- Unit of Psychiatry, Institute of Translational Medicine, Faculty of Health Sciences, University of Macau, Avenida da Universidade, Taipa, Macao SAR, China
| | - Qinge Zhang
- The National Clinical Research Center for Mental Disorders & Beijing Key Laboratory of Mental Disorders Beijing Anding Hospital & the Advanced Innovation Center for Human Brain Protection, Capital Medical University, School of Mental Health, Beijing, China
| | - Shu-Yu Yang
- Department of Pharmacy, Taipei City Hospital, Taipei, Taiwan
| | - Lian-Yu Chen
- Taipei City Psychiatric Center, Taipei City Hospital, Taipei, Taiwan
| | - Kang Sim
- Institute of Mental Health, Buangkok Green Medical Park, Singapore
| | - Yan-Ling He
- Department of Psychiatric Epidemiology, Shanghai Mental Health Center, Shanghai, China
| | - Helen Fk Chiu
- Department of Psychiatry, Chinese University of Hong Kong, Hong Kong SAR, China
| | - Norman Sartorius
- Association for the Improvement of Mental Health Programmes, Geneva, Switzerland
| | - Chay-Hoon Tan
- Department of Pharmacology, National University of Singapore, Singapore
| | - Mian-Yoon Chong
- Chiayi Chang Gung Memorial Hospital and School of Medicine, Chang Gung University, Chiayi, Taiwan
| | - Naotaka Shinfuku
- International Center for Medical Research, Kobe University School of Medicine, Kobe, Japan
| | - Shih-Ku Lin
- Department of Psychiatry, School of Medicine, Taipei Medical University, Taipei, Taiwan
| | - Chee H Ng
- Department of Psychiatry, University of Melbourne, Melbourne, Victoria, Australia
| | - Gabor S Ungvari
- University of Notre Dame Australia, Fremantle, Australia; Division of Psychiatry, School of Medicine, University of Western Australia, Perth, Australia
| | | | | | - Ruzita Jamaluddin
- Department of Psychiatry & Mental Health, Hospital Tuanku Fauziah, Kangar, Perlis, Malaysia
| | - Afzal Javed
- Pakistan Psychiatric Research Centre, Fountain House, Lahore, Pakistan
| | - Hitoshi Iida
- Department of Psychiatry, Faculty of Medicine, Fukuoka University, Fukuoka, Japan
| | - Thiha Swe
- Department of Mental Health, University of Medicine, Magway, Myanmar
| | - Bin Zhang
- Department of Psychiatry and Psychology, Southern Medical University Nanfang Hospital, Guangdong, China; Guangdong-Hong Kong-Macao Greater Bay Area Center for Brain Science and Brain-Inspired Intelligence, Guangzhou, China.
| | - Yu-Tao Xiang
- Unit of Psychiatry, Institute of Translational Medicine, Faculty of Health Sciences, University of Macau, Avenida da Universidade, Taipa, Macao SAR, China.
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13
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Kim HK, Blumberger DM, Daskalakis ZJ. Neurophysiological Biomarkers in Schizophrenia-P50, Mismatch Negativity, and TMS-EMG and TMS-EEG. Front Psychiatry 2020; 11:795. [PMID: 32848953 PMCID: PMC7426515 DOI: 10.3389/fpsyt.2020.00795] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/23/2020] [Accepted: 07/24/2020] [Indexed: 12/16/2022] Open
Abstract
Impaired early auditory processing is a well characterized finding in schizophrenia that is theorized to contribute to clinical symptoms, cognitive impairment, and social dysfunction in patients. Two neurophysiological measures of early auditory processing, P50 gating ("P50") and mismatch negativity (MMN), which measure sensory gating and detection of change in auditory stimuli, respectively, are consistently shown to be impaired in patients with schizophrenia. Transcranial magnetic stimulation (TMS) may also be a potential method by which sensory processing can be assessed, since TMS paradigms can be used to measure GABAB-mediated cortical inhibition that is linked with sensory gating. In this review, we examine the potential of P50, MMN and two TMS paradigms, cortical silent period (CSP) and long-interval intracortical inhibition (LICI), as endophenotypes as well as their ability to be used as predictive markers for interventions targeted at cognitive and psychosocial functioning. Studies consistently support a link between MMN, P50, and cognitive dysfunction, with robust evidence for a link between MMN and psychosocial functioning in schizophrenia as well. Importantly, studies have demonstrated that MMN can be used to predict performance in social and cognitive training tasks. A growing body of studies also supports the potential of MMN to be used as an endophenotype, and future studies are needed to determine if MMN can be used as an endophenotype specifically in schizophrenia. P50, however, has weaker evidence supporting its use as an endophenotype. While CSP and LICI are not as extensively investigated, growing evidence is supporting their potential to be used as an endophenotype in schizophrenia. Future studies that assess the ability of P50, MMN, and TMS neurophysiological measures to predict performance in cognitive and social training programs may identify markers that inform clinical decisions in the treatment of neurocognitive impairments in schizophrenia.
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Affiliation(s)
- Helena K Kim
- Department of Psychiatry, University of Toronto, Toronto, ON, Canada
| | - Daniel M Blumberger
- Department of Psychiatry, University of Toronto, Toronto, ON, Canada.,Temerty Centre for Therapeutic Brain Intervention, Centre for Addiction and Mental Health, Department of Psychiatry, University of Toronto, Toronto, ON, Canada
| | - Zafiris J Daskalakis
- Department of Psychiatry, University of Toronto, Toronto, ON, Canada.,Temerty Centre for Therapeutic Brain Intervention, Centre for Addiction and Mental Health, Department of Psychiatry, University of Toronto, Toronto, ON, Canada
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Kim S, Jung WH, Howes OD, Veronese M, Turkheimer FE, Lee YS, Lee JS, Kim E, Kwon JS. Frontostriatal functional connectivity and striatal dopamine synthesis capacity in schizophrenia in terms of antipsychotic responsiveness: an [ 18F]DOPA PET and fMRI study. Psychol Med 2019; 49:2533-2542. [PMID: 30460891 DOI: 10.1017/s0033291718003471] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
BACKGROUND Given that only a subgroup of patients with schizophrenia responds to first-line antipsychotic drugs, a key clinical question is what underlies treatment response. Observations that prefrontal activity correlates with striatal dopaminergic function, have led to the hypothesis that disrupted frontostriatal functional connectivity (FC) could be associated with altered dopaminergic function. Thus, the aim of this study was to investigate the relationship between frontostriatal FC and striatal dopamine synthesis capacity in patients with schizophrenia who had responded to first-line antipsychotic drug compared with those who had failed but responded to clozapine. METHODS Twenty-four symptomatically stable patients with schizophrenia were recruited from Seoul National University Hospital, 12 of which responded to first-line antipsychotic drugs (first-line AP group) and 12 under clozapine (clozapine group), along with 12 matched healthy controls. All participants underwent resting-state functional magnetic resonance imaging and [18F]DOPA PET scans. RESULTS No significant difference was found in the total PANSS score between the patient groups. Voxel-based analysis showed a significant correlation between frontal FC to the associative striatum and the influx rate constant of [18F]DOPA in the corresponding region in the first-line AP group. Region-of-interest analysis confirmed the result (control group: R2 = 0.019, p = 0.665; first-line AP group: R2 = 0.675, p < 0.001; clozapine group: R2 = 0.324, p = 0.054) and the correlation coefficients were significantly different between the groups. CONCLUSIONS The relationship between striatal dopamine synthesis capacity and frontostriatal FC is different between responders to first-line treatment and clozapine treatment in schizophrenia, indicating that a different pathophysiology could underlie schizophrenia in patients who respond to first-line treatments relative to those who do not.
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Affiliation(s)
- Seoyoung Kim
- Department of Neuropsychiatry, Seoul National University Bundang Hospital, Gyeonggi-do, Republic of Korea
| | - Wi Hoon Jung
- Department of Psychology, College of Liberal Arts, Korea University, Seoul, Republic of Korea
| | - Oliver D Howes
- Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK
- Psychiatric Imaging, Medical Research Council Clinical Sciences Centre, Imperial College London, Hammersmith Hospital Campus, London, UK
| | - Mattia Veronese
- Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK
| | - Federico E Turkheimer
- Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK
| | - Yun-Sang Lee
- Department of Nuclear Medicine, College of Medicine, Seoul National University, Seoul, Republic of Korea
| | - Jae Sung Lee
- Department of Nuclear Medicine, College of Medicine, Seoul National University, Seoul, Republic of Korea
- Department of Brain & Cognitive Sciences, College of Natural Sciences, Seoul National University, Seoul, Republic of Korea
| | - Euitae Kim
- Department of Neuropsychiatry, Seoul National University Bundang Hospital, Gyeonggi-do, Republic of Korea
- Department of Psychiatry, College of Medicine, Seoul National University, Seoul, Republic of Korea
| | - Jun Soo Kwon
- Department of Brain & Cognitive Sciences, College of Natural Sciences, Seoul National University, Seoul, Republic of Korea
- Department of Psychiatry, College of Medicine, Seoul National University, Seoul, Republic of Korea
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15
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CSF GABA is reduced in first-episode psychosis and associates to symptom severity. Mol Psychiatry 2018; 23:1244-1250. [PMID: 28289277 PMCID: PMC5984082 DOI: 10.1038/mp.2017.25] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/22/2016] [Revised: 12/09/2016] [Accepted: 01/09/2017] [Indexed: 12/31/2022]
Abstract
Schizophrenia is characterized by a multiplicity of symptoms arising from almost all domains of mental function. γ-Aminobutyric acid (GABA) is the primary inhibitory neurotransmitter in the brain and is increasingly recognized to have a significant role in the pathophysiology of the disorder. In the present study, cerebrospinal fluid (CSF) concentrations of GABA were analyzed in 41 first-episode psychosis (FEP) patients and 21 age- and sex-matched healthy volunteers by high-performance liquid chromatography. We found lower CSF GABA concentration in FEP patients compared with that in the healthy volunteers, a condition that was unrelated to antipsychotic and/or anxiolytic medication. Moreover, lower CSF GABA levels were associated with total and general score of Positive and Negative Syndrome Scale, illness severity and probably with a poor performance in a test of attention. This study offers clinical in vivo evidence for a potential role of GABA in early-stage schizophrenia.
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16
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Plevin D, Mohan T, Bastiampillai T. The role of the GABAergic system in catatonia-Insights from clozapine and benzodiazepines. Asian J Psychiatr 2018; 32:145-146. [PMID: 29272785 DOI: 10.1016/j.ajp.2017.12.008] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/29/2017] [Revised: 12/13/2017] [Accepted: 12/14/2017] [Indexed: 11/29/2022]
Affiliation(s)
- David Plevin
- Flinders Medical Centre, Bedford Park, SA 5042, Australia.
| | - Titus Mohan
- Flinders Medical Centre, Bedford Park, SA 5042, Australia
| | - Tarun Bastiampillai
- South Australian Health and Medical Research Institute (SAHMRI) - Mind and Brain, Adelaide, Australia
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17
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Arumugham SS, Thirthalli J, Andrade C. Efficacy and safety of combining clozapine with electrical or magnetic brain stimulation in treatment-refractory schizophrenia. Expert Rev Clin Pharmacol 2016; 9:1245-52. [DOI: 10.1080/17512433.2016.1200971] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Affiliation(s)
- Shyam Sundar Arumugham
- Department of Psychiatry, National Institute of Mental Health and Neurosciences, Bangalore, India
| | - Jagadisha Thirthalli
- Department of Psychiatry, National Institute of Mental Health and Neurosciences, Bangalore, India
| | - Chittaranjan Andrade
- Department of Psychopharmacology, National Institute of Mental Health and Neurosciences, Bangalore, India
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18
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Kumar SR, Sinha VK, Tikka SK, Goyal N. Gamma activity model for treatment-resistant bipolar psychotic mania. Indian J Pharmacol 2016; 47:215-8. [PMID: 25878386 PMCID: PMC4386135 DOI: 10.4103/0253-7613.153434] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/22/2014] [Revised: 02/09/2015] [Accepted: 02/21/2015] [Indexed: 11/04/2022] Open
Abstract
OBJECTIVES The objective was to investigate the effect of clozapine on spontaneous gamma activity in treatment-resistant bipolar psychotic mania. METHODS Patients with treatment-resistant (TR) bipolar psychotic mania on clozapine monotherapy and nontreatment-resistant bipolar psychotic mania patients receiving lithium were prospectively studied for 6 weeks on severity of psychopathology and 30-49 Hz gamma spectral power. RESULTS Spectral power significantly increased in the lithium group and decreased in the clozapine group; no within group significant difference found. CONCLUSIONS We propose a model highlighting the role of gamma spectral power and modulations of GABAergic neurotransmission in TR bipolar psychotic mania.
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Affiliation(s)
- Shashi Ranjan Kumar
- Department of Psychiatry and K. S. Mani Center for Cognitive Neurosciences, Central Institute of Psychiatry, Ranchi, Jharkhand, India
| | - Vinod Kumar Sinha
- Department of Psychiatry and K. S. Mani Center for Cognitive Neurosciences, Central Institute of Psychiatry, Ranchi, Jharkhand, India
| | - Sai Krishna Tikka
- Department of Psychiatry and K. S. Mani Center for Cognitive Neurosciences, Central Institute of Psychiatry, Ranchi, Jharkhand, India
| | - Nishant Goyal
- Department of Psychiatry and K. S. Mani Center for Cognitive Neurosciences, Central Institute of Psychiatry, Ranchi, Jharkhand, India
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19
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Abdul Wahab NA, Wahab S, Abdul Rahman AH, Sidek D, Zakaria MN. The Hyperactivity of Efferent Auditory System in Patients with Schizophrenia: A Transient Evoked Otoacoustic Emissions Study. Psychiatry Investig 2016; 13:82-8. [PMID: 26766950 PMCID: PMC4701690 DOI: 10.4306/pi.2016.13.1.82] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/11/2015] [Revised: 05/18/2015] [Accepted: 05/30/2015] [Indexed: 02/07/2023] Open
Abstract
OBJECTIVE Electrophysiological studies, which are mostly focused on afferent pathway, have proven that auditory processing deficits exist in patients with schizophrenia. Nevertheless, reports on the suppressive effect of efferent auditory pathway on cochlear outer hair cells among schizophrenia patients are limited. The present, case-control, study examined the contralateral suppression of transient evoked otoacoustic emissions (TEOAEs) in patients with schizophrenia. METHODS Participants were twenty-three healthy controls and sixteen schizophrenia patients with normal hearing, middle ear and cochlear outer hair cells function. Absolute non-linear and linear TEOAEs were measured in both ears by delivering clicks stimuli at 80 dB SPL and 60 dB SPL respectively. Subsequently, contralateral suppression was determined by subtracting the absolute TEOAEs response obtained at 60 dBpe SPL during the absence and presence of contralateral white noise delivered at 65 dB HL. No attention tasks were conducted during measurements. RESULTS We found no significant difference in absolute TEOAEs responses at 80 dB SPL, in either diagnosis or ear groups (p>0.05). However, the overall contralateral suppression was significantly larger in schizophrenia patients (p<0.05). Specifically, patients with schizophrenia demonstrated significantly increased right ear contralateral suppression compared to healthy control (p<0.05). CONCLUSION The present findings suggest increased inhibitory effect of efferent auditory pathway especially on the right cochlear outer hair cells. Further studies to investigate increased suppressive effects are crucial to expand the current understanding of auditory hallucination mechanisms in schizophrenia patients.
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Affiliation(s)
- Noor Alaudin Abdul Wahab
- Audiology Programme, School of Health Sciences, Universiti Sains Malaysia, Kelantan, Malaysia
- Audiology Programme, School of Rehabilitation Sciences, Faculty of Health Sciences, Universiti Kebangsaan Malaysia, Wilayah Persekutuan, Malaysia
| | - Suzaily Wahab
- Department of Psychiatry, Faculty of Medicine, Universiti Kebangsaan Malaysia Medical Center, Wilayah Persekutuan, Malaysia
| | - Abdul Hamid Abdul Rahman
- Department of Psychiatry, Faculty of Medicine, Universiti Kebangsaan Malaysia Medical Center, Wilayah Persekutuan, Malaysia
| | - Dinsuhaimi Sidek
- Department of Otorhinolaryngology, School of Medicine, Universiti Sains Malaysia, Kelantan, Malaysia
| | - Mohd. Normani Zakaria
- Audiology Programme, School of Health Sciences, Universiti Sains Malaysia, Kelantan, Malaysia
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Zink M, Correll CU. Glutamatergic agents for schizophrenia: current evidence and perspectives. Expert Rev Clin Pharmacol 2015; 8:335-52. [PMID: 25916667 DOI: 10.1586/17512433.2015.1040393] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Suboptimal outcomes in schizophrenia are a consequence of lacking insight into the etiology, biomarkers and treatment-relevant subgroups, the therapeutic restriction to dopaminergic-modulating antipsychotics that fail to significantly improve negative and cognitive symptoms, non-adherence, and, in the case of treatment-resistance, the underutilization of clozapine. Evidence suggests additional, extra-dopaminergic abnormalities in amino acid neurotransmission, particularly the glutamatergic system. Antidopaminergic antipsychotics modulate this system on several levels, as do mood stabilizers, including lamotrigine, topiramate and pregabaline. Recently, agonists at metabotropic glutamate receptors and glycine uptake inhibitors failed in large placebo-controlled trials for schizophrenia. Problems to overcome for successfully leveraging glutamatergic agents for schizophrenia are patient selection, focus on positive symptoms and late disease stages, and dose-response relationships. Because glutamate guides processes of brain development and maturation, clinical research should focus on the at-risk mental state or first-episode psychosis, address cognition and negative symptoms and use monotherapy designs in parallel to augmentation strategies.
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Affiliation(s)
- Mathias Zink
- Department of Psychiatry and Psychotherapy, Central Institute of Mental Health, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
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Association studies of genomic variants with treatment response to risperidone, clozapine, quetiapine and chlorpromazine in the Chinese Han population. THE PHARMACOGENOMICS JOURNAL 2015; 16:357-65. [PMID: 26282453 DOI: 10.1038/tpj.2015.61] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Received: 04/13/2015] [Revised: 06/08/2015] [Accepted: 07/14/2015] [Indexed: 01/01/2023]
Abstract
Schizophrenia is a widespread mental disease with a prevalence of about 1% in the world population. Continuous long-term treatment is required to maintain social functioning and prevent symptom relapse of schizophrenia patients. However, there are considerable individual differences in response to the antipsychotic drugs. There is a pressing need to identify more drug-response-related markers. But most pharmacogenomics of schizophrenia have typically focused on a few candidate genes in small sample size. In this study, 995 subjects were selected for discovering the drug-response-related markers. A total of 77 single-nucleotide polymorphisms of 25 genes have been investigated for four commonly used antipsychotic drugs in China: risperidone, clozapine, quetiapine, and chlorpromazine. Significant associations with treatment response for several genes, such as CYP2D6, CYP2C19, COMT, ABCB1, DRD3 and HTR2C have been verified in our study. Also, we found several new candidate genes (TNIK, RELN, NOTCH4 and SLC6A2) and combinations (haplotype rs1544325-rs5993883-rs6269-rs4818 in COMT) that are associated with treatment response to the four drugs. Also, multivariate interactions analysis demonstrated the combination of rs6269 in COMT and rs3813929 in HTR2C may work as a predictor to improve the clinical antipsychotic response. So our study is of great significance to improve current knowledge on the pharmacogenomics of schizophrenia, thus promoting the implementation of personalized medicine in schizophrenia.The Pharmacogenomics Journal advance online publication, 18 August 2015; doi:10.1038/tpj.2015.61.
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Rogasch NC, Daskalakis ZJ, Fitzgerald PB. Cortical inhibition of distinct mechanisms in the dorsolateral prefrontal cortex is related to working memory performance: A TMS–EEG study. Cortex 2015; 64:68-77. [DOI: 10.1016/j.cortex.2014.10.003] [Citation(s) in RCA: 76] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2014] [Revised: 08/23/2014] [Accepted: 10/07/2014] [Indexed: 10/24/2022]
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Monga V, Broucek M, Amani M, Ramaswamy S. Clozapine and concomitant chemotherapy in a patient with schizophrenia and new onset esophageal cancer. Psychooncology 2015; 24:971-2. [DOI: 10.1002/pon.3744] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2014] [Accepted: 12/10/2014] [Indexed: 11/10/2022]
Affiliation(s)
- Varun Monga
- Department of Psychiatry; Creighton University; Omaha NE USA
| | - Marin Broucek
- Department of Psychiatry; Creighton University; Omaha NE USA
| | - Mojgan Amani
- Department of Psychiatry; Creighton University; Omaha NE USA
| | - Sriram Ramaswamy
- Nebraska Western Iowa VA Healthcare System; Creighton University; Omaha NE USA
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Vukadinovic Z. Elevated striatal dopamine attenuates nigrothalamic inputs and impairs transthalamic cortico-cortical communication in schizophrenia: A hypothesis. Med Hypotheses 2015; 84:47-52. [DOI: 10.1016/j.mehy.2014.11.014] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2014] [Revised: 10/28/2014] [Accepted: 11/11/2014] [Indexed: 12/12/2022]
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Antipsychotic treatment modulates glutamate transport and NMDA receptor expression. Eur Arch Psychiatry Clin Neurosci 2014; 264 Suppl 1:S67-82. [PMID: 25214389 DOI: 10.1007/s00406-014-0534-4] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/02/2014] [Accepted: 09/02/2014] [Indexed: 12/21/2022]
Abstract
Schizophrenia patients often suffer from treatment-resistant cognitive and negative symptoms, both of which are influenced by glutamate neurotransmission. Innovative therapeutic strategies such as agonists at metabotropic glutamate receptors or glycin reuptake inhibitors try to modulate the brain's glutamate network. Interactions of amino acids with monoamines have been described on several levels, and first- and second-generation antipsychotic agents (FGAs, SGAs) are known to exert modulatory effects on the glutamatergic system. This review summarizes the current knowledge on effects of FGAs and SGAs on glutamate transport and receptor expression derived from pharmacological studies. Such studies serve as a control for molecular findings in schizophrenia brain tissue and are clinically relevant. Moreover, they may validate animal models for psychosis, foster basic research on antipsychotic substances and finally lead to a better understanding of how monoaminergic and amino acid neurotransmissions are intertwined. In the light of these results, important differences dependent on antipsychotic substances, dosage and duration of treatment became obvious. While some post-mortem findings might be confounded with multifold drug effects, others are unlikely to be influenced by antipsychotic treatment and could represent important markers of schizophrenia pathophysiology. In similarity to the convergence of toxic and psychotomimetic effects of dopaminergic, serotonergic and anti-glutamatergic substances, the therapeutic mechanisms of SGAs might merge on a yet to be defined molecular level. In particular, serotonergic effects of SGAs, such as an agonism at 5HT1A receptors, represent important targets for further clinical research.
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27
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Frau R, Bini V, Pillolla G, Malherbe P, Pardu A, Thomas AW, Devoto P, Bortolato M. Positive allosteric modulation of GABAB receptors ameliorates sensorimotor gating in rodent models. CNS Neurosci Ther 2014; 20:679-84. [PMID: 24703381 DOI: 10.1111/cns.12261] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2014] [Revised: 03/07/2014] [Accepted: 03/08/2014] [Indexed: 12/14/2022] Open
Abstract
BACKGROUND Converging evidence points to the involvement of γ-amino-butyric acid B receptors (GABABRs) in the regulation of information processing. We previously showed that GABABR agonists exhibit antipsychotic-like properties in rodent models of sensorimotor gating deficits, as measured by the prepulse inhibition (PPI) of the acoustic startle reflex. The therapeutic potential of these agents, however, is limited by their neuromuscular side effects; thus, in this study, we analyzed whether rac-BHFF, a potent GABABR-positive allosteric modulator (PAM), could counter spontaneous and pharmacologically induced PPI deficits across various rodent models. METHODS We tested the antipsychotic effects of rac-BHFF on the PPI deficits caused by the N-methyl-D-aspartate glutamate receptor antagonist dizocilpine, in Sprague-Dawley rats and C57BL/6 mice. Furthermore, we verified whether rac-BHFF ameliorated the spontaneous PPI impairments in DBA/2J mice. RESULTS rac-BHFF dose-dependently countered the PPI deficits across all three models, in a fashion akin to the GABABR agonist baclofen and the atypical antipsychotic clozapine; in contrast with these compounds, however, rac-BHFF did not affect startle magnitude. CONCLUSIONS The present data further support the implication of GABABRs in the modulation of sensorimotor gating and point to their PAMs as a novel promising tool for antipsychotic treatment, with fewer side effects than GABABR agonists.
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Affiliation(s)
- Roberto Frau
- "Guy Everett" Laboratory, Department of Biomedical Sciences, University of Cagliari, Cagliari, Italy; Tourette Syndrome Center, University of Cagliari, Cagliari, Italy
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Fatemi SH, Folsom TD, Rooney RJ, Thuras PD. Expression of GABAA α2-, β1- and ε-receptors are altered significantly in the lateral cerebellum of subjects with schizophrenia, major depression and bipolar disorder. Transl Psychiatry 2013; 3:e303. [PMID: 24022508 PMCID: PMC3784760 DOI: 10.1038/tp.2013.64] [Citation(s) in RCA: 88] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/22/2013] [Revised: 06/17/2013] [Accepted: 07/10/2013] [Indexed: 12/15/2022] Open
Abstract
There is abundant evidence that dysfunction of the γ-aminobutyric acid (GABA)ergic signaling system is implicated in the pathology of schizophrenia and mood disorders. Less is known about the alterations in protein expression of GABA receptor subunits in brains of subjects with schizophrenia and mood disorders. We have previously demonstrated reduced expression of GABA(B) receptor subunits 1 and 2 (GABBR1 and GABBR2) in the lateral cerebella of subjects with schizophrenia, bipolar disorder and major depressive disorder. In the current study, we have expanded these studies to examine the mRNA and protein expression of 12 GABA(A) subunit proteins (α1, α2, α3, α5, α6, β1, β2, β3, δ, ε, γ2 and γ3) in the lateral cerebella from the same set of subjects with schizophrenia (N=9-15), bipolar disorder (N=10-15) and major depression (N=12-15) versus healthy controls (N=10-15). We found significant group effects for protein levels of the α2-, β1- and ε-subunits across treatment groups. We also found a significant group effect for mRNA levels of the α1-subunit across treatment groups. New avenues for treatment, such as the use of neurosteroids to promote GABA modulation, could potentially ameliorate GABAergic dysfunction in these disorders.
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Affiliation(s)
- S H Fatemi
- Division of Neuroscience Research, Department of Psychiatry, University of Minnesota Medical School, Minneapolis, MN, USA,Department of Pharmacology, University of Minnesota Medical School, Minneapolis, MN, USA,Department of Neuroscience, University of Minnesota Medical School, Minneapolis, MN, USA,Division of Neuroscience Research, Department of Psychiatry, University of Minnesota Medical School, 420 Delaware St SE, MMC 392, Minneapolis, MN 55455, USA. E-mail:
| | - T D Folsom
- Division of Neuroscience Research, Department of Psychiatry, University of Minnesota Medical School, Minneapolis, MN, USA
| | | | - P D Thuras
- Department of Psychiatry, VA Medical Center Minneapolis, MN, USA
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Kohlmeier KA, Vardar B, Christensen MH. γ-Hydroxybutyric acid induces actions via the GABAB receptor in arousal and motor control-related nuclei: implications for therapeutic actions in behavioral state disorders. Neuroscience 2013; 248:261-77. [PMID: 23791974 DOI: 10.1016/j.neuroscience.2013.06.011] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2013] [Revised: 05/22/2013] [Accepted: 06/07/2013] [Indexed: 10/26/2022]
Abstract
γ-Hydroxybutyric acid (GHB) is used as an effective therapeutic for reducing the hypersomnolence and cataplexy (loss of motor control) of the sleeping disorder, narcolepsy, with an immediate pharmacologic behavioral action of inducing a natural sleep-like state. Despite its clinical use, few studies have examined the cellular actions of this drug on behavioral state-related neurons. Therefore, we monitored GHB-induced responses using calcium imaging within the laterodorsal tegmentum (LDT) and the dorsal raphe (DR), two pontine nuclei important in state and motor control. In addition, we recorded GHB-induced membrane responses using whole cell, patch clamp electrophysiology of immunohistochemically-identified principal neurons within these nuclei. GHB induced GABAB receptor-mediated rises in calcium in neurons of the LDT and the DR. However, the pattern and amplitude of calcium rises differed greatly between these two nuclei. GHB induced GABAB receptor antagonist-sensitive outward currents/hyperpolarizations in immunohistochemically-identified cholinergic LDT and serotonergic DR neurons. However, GHB had this action in a greater proportion of DR cells than LDT neurons. Further, larger inhibitory currents were induced in DR cells when compared to the amplitude of GHB-induced current in LDT-responding cells. Finally, NCS-382 and HOCPCA, a reported antagonist and agonist specific to activity at the putative GHB receptor, respectively, with no demonstrated binding at the GABAB receptor, failed to block GHB-induced effects or elicit any discernible electrophysiological action when applied alone, indicating a lack of involvement of a GHB receptor in mediating GHB actions. Taken together, our data support the conclusion that GHB may be exerting its actions on state and motor control, in part, via an acutely mediated strong inhibition of serotonergic DR neurons and a more modest inhibitory action on a smaller proportion of LDT cholinergic neurons. Given the roles played by these nuclei, these actions are consistent with acute pharmacologic effects of GHB: hypotonia and promotion of sleep, including presence of REM, a sub-state of sleep. Differences in GHB-mediated calcium suggest differential regulation of calcium-dependent processes, which may also contribute to functioning of the LDT and DR in state and motor control and the therapeutic pharmacologic actions of GHB, which develop following chronic administration. These findings add to knowledge of cellular actions of GHB and it is hoped that, combined with findings from other studies examining GHB neurotransmission, these data can contribute to development of highly targeted therapeutics at the GABAB receptor for management of human disorders presenting with alterations in motor and arousal control.
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Affiliation(s)
- K A Kohlmeier
- Department of Drug Design and Pharmacology, Faculty of Health Sciences, Universitsparken 2, University of Copenhagen, Copenhagen 2100, Denmark.
| | - B Vardar
- Department of Drug Design and Pharmacology, Faculty of Health Sciences, Universitsparken 2, University of Copenhagen, Copenhagen 2100, Denmark
| | - M H Christensen
- Department of Drug Design and Pharmacology, Faculty of Health Sciences, Universitsparken 2, University of Copenhagen, Copenhagen 2100, Denmark
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Peselmann N, Schmitt A, Gebicke-Haerter PJ, Zink M. Aripiprazole differentially regulates the expression of Gad67 and γ-aminobutyric acid transporters in rat brain. Eur Arch Psychiatry Clin Neurosci 2013; 263:285-97. [PMID: 22968646 DOI: 10.1007/s00406-012-0367-y] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/22/2012] [Accepted: 08/29/2012] [Indexed: 12/13/2022]
Abstract
The molecular etiology of schizophrenia comprises abnormal neurotransmission of the amino acid GABA (γ-aminobutyric acid). Neuropathological studies convincingly revealed reduced expression of glutamic acid decarboxylase (Gad67) in GABAergic interneurons. Several antipsychotics influence the expression of GABAergic genes, but aripiprazole (APZ), a partial dopaminergic and serotonergic receptor agonist, has not been involved into these studies so far. We treated Sprague-Dawley rats for 4 weeks or 4 months with APZ suspended in drinking water and doses of 10 and 40 mg per kg body weight. Gene expression of Gad67, the vesicular GABA transporter Slc32a1 (solute carrier family, Vgat), the transmembrane transporters Slc6a1 (Gat1) and Slc6a11 (Gat3) was assessed by semiquantitative radioactive in situ hybridization. APZ treatment resulted in time- and dose-dependent effects with qualitative differences between brain regions. In the 10-mg group, Slc6a1 was strongly induced after 4 weeks in the hippocampus, amygdala, and cerebral cortex, followed by an induction of Gad67 in the same regions after 4 months, while frontocortical regions as well as basal ganglia showed dose-dependent reductions of Gad67 expression after 4 months. In several frontocortical and subcortical regions, we observed a decrease of Slc32a1 and an increase of Slc6a11 expression. In conclusion, APZ modulates gene expression of GABAergic marker genes involved into pathogenetic theories of schizophrenia. APZ only partially mirrors the effects of other antipsychotics with some important differences regarding brain regions. The findings might be explained by regulatory connections between serotonergic, GABAergic, and dopaminergic neurotransmission and should be validated in behavioral animal models of psychotic disorders.
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Affiliation(s)
- Nina Peselmann
- Department of Psychiatry and Psychotherapy, Central Institute of Mental Health, Medical Faculty Mannheim, University of Heidelberg, J5, 68159 Mannheim, Germany
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Li X, Hartwell KJ, Owens M, Lematty T, Borckardt JJ, Hanlon CA, Brady KT, George MS. Repetitive transcranial magnetic stimulation of the dorsolateral prefrontal cortex reduces nicotine cue craving. Biol Psychiatry 2013; 73:714-20. [PMID: 23485014 PMCID: PMC3615051 DOI: 10.1016/j.biopsych.2013.01.003] [Citation(s) in RCA: 146] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/21/2012] [Revised: 01/04/2013] [Accepted: 01/04/2013] [Indexed: 11/21/2022]
Abstract
BACKGROUND Repetitive transcranial magnetic stimulation (rTMS) can noninvasively stimulate the brain and transiently amplify or block behaviors mediated through a region. We hypothesized that a single high-frequency rTMS session over the left dorsolateral prefrontal cortex (DLPFC) would reduce cue craving for cigarettes compared with a sham TMS session. METHODS Sixteen non-treatment-seeking, nicotine-dependent participants were randomized to receive either real high-frequency rTMS (10 Hz, 100% resting motor threshold, 5-sec on, 10-sec off for 15 min; 3000 pulses) or active sham (eSham) TMS over the DLPFC in two visits with 1 week between visits. The participants received cue exposure before and after rTMS and rated their craving after each block of cue presentation. RESULTS Stimulation of the left DLFPC with real, but not sham, rTMS reduced craving significantly from baseline (64.1±5.9 vs. 45.7±6.4, t = 2.69, p = .018). When compared with neutral cue craving, the effect of real TMS on cue craving was significantly greater than the effect of sham TMS (12.5±10.4 vs. -9.1±10.4; t = 2.07, p = .049). More decreases in subjective craving induced by TMS correlated positively with higher Fagerström Test for Nicotine Dependence score (r = .58, p = .031) and more cigarettes smoked per day (r = .57, p = .035). CONCLUSIONS One session of high-frequency rTMS (10 Hz) of the left DLPFC significantly reduced subjective craving induced by smoking cues in nicotine-dependent participants. Additional studies are needed to explore rTMS as an aid to smoking cessation.
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Affiliation(s)
- Xingbao Li
- Medical University of South Carolina, Charleston, SC 29425, USA.
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Ferrarelli F, Sarasso S, Guller Y, Riedner BA, Peterson MJ, Bellesi M, Massimini M, Postle BR, Tononi G. Reduced natural oscillatory frequency of frontal thalamocortical circuits in schizophrenia. ACTA ACUST UNITED AC 2012; 69:766-74. [PMID: 22474071 DOI: 10.1001/archgenpsychiatry.2012.147] [Citation(s) in RCA: 105] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
CONTEXT Converging evidence from electrophysiological studies suggests that in individuals with schizophrenia, electroencephalographic frontal fast oscillations are reduced. It is still unclear whether this reduction reflects an intrinsic deficit of underlying cortical/thalamocortical circuits and whether this deficit is specific for frontal regions. Recent electrophysiological studies in healthy individuals have established that, when perturbed, different brain regions oscillate at a specific, intrinsically generated dominant frequency, the natural frequency. OBJECTIVE To assess the natural frequency of the posterior parietal, motor, premotor, and prefrontal cortices in patients with schizophrenia and healthy control subjects. DESIGN High-density electroencephalographic recordings during transcranial magnetic stimulation of 4 cortical areas were performed. Several transcranial magnetic stimulation–evoked electroencephalographic oscillation parameters, including synchronization, amplitude, and natural frequency, were compared across the schizophrenia and healthy control groups. SETTING Wisconsin Psychiatric Institute and Clinic, University of Wisconsin–Madison. PARTICIPANTS Twenty patients with schizophrenia and 20 age-matched healthy control subjects. MAIN OUTCOME MEASURES High-density electroencephalographic measurements of transcranial magnetic stimulation–evoked activity in 4 cortical areas, scores on the Positive and Negative Syndrome Scale, and performance scores (reaction time, accuracy) on 2 computerized tasks (word memory [Penn Word Recognition Test] and facial memory [Penn Facial Memory Test]). RESULTS Patients with schizophrenia showed a slowing in the natural frequency of the frontal/prefrontal regions compared with healthy control subjects (from an average of a 2-Hz decrease for the motor area to an almost 10-Hz decrease for the prefrontal cortex). The prefrontal natural frequency of individuals with schizophrenia was slower than in any healthy comparison subject and correlated with both positive Positive and Negative Syndrome Scale scores and reaction time on the Penn Word Recognition Test. CONCLUSIONS These findings suggest that patients with schizophrenia have an intrinsic slowing in the natural frequency of frontal cortical/thalamocortical circuits, that this slowing is not present in parietal areas, and that the prefrontal natural frequency can predict some of the symptoms as well as the cognitive dysfunctions of schizophrenia.
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Rajji TK, Chow TW, Voineskos AN, Links KA, Miranda D, Mamo DC, Ismail Z, Pollock BG, Mulsant BH. Cholinergic pathways and cognition in patients with schizophrenia: a pilot study. Schizophr Res 2012; 139:46-52. [PMID: 22727706 DOI: 10.1016/j.schres.2012.06.006] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/02/2012] [Revised: 05/31/2012] [Accepted: 06/04/2012] [Indexed: 11/30/2022]
Abstract
BACKGROUND Cognitive deficits are core features in schizophrenia. Disruption in cholinergic neurotransmission has been associated with executive dysfunction in animals and humans. The objective of this study was to evaluate the impact of compromised cholinergic pathways on executive versus non-executive cognitive functions of patients with schizophrenia. METHODS 62 patients with schizophrenia and 62 age- and sex-matched non-psychiatric control subjects ("controls") were assessed and compared using: clinical measures, cognitive measures of global cognition, executive function, and memory; and an MRI-based visual rating scale that assesses damage strategically localized within the cholinergic pathways. RESULTS 11 of the 62 patients with schizophrenia (17.7%) and 6 of the 62 controls (9.7%) had compromised cholinergic pathways. These proportions were not statistically significant. Patients and controls with compromised cholinergic pathways were more impaired on measures related to executive function than patients or controls without compromised pathways. CONCLUSIONS Patients with schizophrenia have worse executive function than controls. Compromised cholinergic pathways appear to worsen the executive dysfunction observed in schizophrenia. If these preliminary findings are replicated, they could lead to the identification of a subgroup of patients with schizophrenia who could specifically benefit from interventions enhancing cholinergic neurotransmission.
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Affiliation(s)
- Tarek K Rajji
- Geriatric Mental Health Program, Centre for Addiction and Mental Health, Toronto, Canada
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Association study of 27 annotated genes for clozapine pharmacogenetics: validation of preexisting studies and identification of a new candidate gene, ABCB1, for treatment response. J Clin Psychopharmacol 2012; 32:441-8. [PMID: 22722500 DOI: 10.1097/jcp.0b013e31825ac35c] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
OBJECTIVE Pharmacogenetic studies on clozapine (CLZ) have provided meaningful insights but have shown redundancies owing to wide interindividual variability and insufficient replication. The present study was designed to validate hitherto suggested candidate genes on CLZ pharmacokinetics and pharmacodynamics and explore new markers through an integrative study. METHODS Based on a literature review, a total of 127 variations in 27 candidate genes were selected and analyzed. Ninety-six schizophrenic patients of Korean ethnicity with constant CLZ dosing were recruited, and information on body weight and smoking habits was gathered, as well as plasma drug levels and treatment responses. RESULTS Among the pharmacokinetic-related single nucleotide polymorphisms, rs2069521 and rs2069522 in CYP1A2 for CLZ/(dose/weight) and norclozapine/(dose/weight) and rs1135840 in CYP2D6 for norclozapine/CLZ showed borderline associations that were insignificant after correction for multiple testing. Regarding treatment response, significant associations were exhibited in rs7787082 and rs10248420 of ABCB1 (P = 0.0005 and P = 0.0013, respectively) even after correction, and the rs7787082 G and rs10248420 A alleles in ABCB1 were more frequently observed in nonresponders. We also observed a trend in the associations of rs13064530 in HRH1 and rs4938013 in DRD2/ANKK1 with treatment response. CONCLUSIONS We could not convincingly replicate most of the previous studies, a result that is possibly due to modest association between the suggested genes. Rather, we found a new candidate gene, ABCB1, for treatment response, which may provide a hypothesis on the relationship between the blood-brain distribution of CLZ and its clinical efficacy.
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Abstract
Neurophysiological studies suggest that clozapine may facilitate γ-aminobutyric acid (GABAergic) neurotransmission. Therefore, we studied the interaction between clozapine and the GABAB receptor (GABABR). We showed that clozapine, and not N-desmethylclozapine, which is a metabolite of clozapine, increased the binding of the GABABR antagonist, [³H]-CGP54626A, at GABABRs. Linear regression analysis showed that the correlation between the dose of clozapine and the increase of [³H]-CGP54626A binding was significant. The curve of specific [³H]-CGP54626A binding in competition with different concentrations of GABA was left shifted in the presence of clozapine. With HEK293 cells overexpressing GABABR, we showed that clozapine had a significant increase of [³H]-CGP54626A binding at GABABR1 subunit, which provided a clue of the potential therapeutic target of clozapine.
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Wing VC, Wass CE, Soh DW, George TP. A review of neurobiological vulnerability factors and treatment implications for comorbid tobacco dependence in schizophrenia. Ann N Y Acad Sci 2011; 1248:89-106. [DOI: 10.1111/j.1749-6632.2011.06261.x] [Citation(s) in RCA: 78] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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Vukadinovic Z, Rosenzweig I. Abnormalities in thalamic neurophysiology in schizophrenia: could psychosis be a result of potassium channel dysfunction? Neurosci Biobehav Rev 2011; 36:960-8. [PMID: 22138503 DOI: 10.1016/j.neubiorev.2011.11.005] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2011] [Revised: 11/11/2011] [Accepted: 11/20/2011] [Indexed: 10/14/2022]
Abstract
Psychosis in schizophrenia is associated with source-monitoring deficits whereby self-initiated behaviors become attributed to outside sources. One of the proposed functions of the thalamus is to adjust sensory responsiveness in accordance with the behavioral contextual cues. The thalamus is markedly affected in schizophrenia, and thalamic dysfunction may here result in reduced ability to adjust sensory responsiveness to ongoing behavior. One of the ways in which the thalamus accomplishes the adjustment of sensory processing is by a neurophysiological shift to post-inhibitory burst firing mode prior to and during certain exploratory actions. Reduced amount of thalamic burst firing may result from increased neuronal excitability secondary to a reported potassium channel dysfunction in schizophrenia. Pharmacological agents that reduce the excitability of thalamic cells and thereby promote burst firing by and large tend to have antipsychotic effects.
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Affiliation(s)
- Zoran Vukadinovic
- Montefiore Medical Center, Albert Einstein College of Medicine, Department of Psychiatry and Behavioral Sciences, 111 E 210th Street, Bronx, NY 10467, USA.
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Fatemi SH, Folsom TD, Thuras PD. Deficits in GABA(B) receptor system in schizophrenia and mood disorders: a postmortem study. Schizophr Res 2011; 128:37-43. [PMID: 21303731 PMCID: PMC3085603 DOI: 10.1016/j.schres.2010.12.025] [Citation(s) in RCA: 99] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/29/2010] [Revised: 12/14/2010] [Accepted: 12/20/2010] [Indexed: 11/15/2022]
Abstract
Postmortem and genetic studies have clearly demonstrated changes in GABA(B) receptors in neuropsychiatric disorders such as autism, bipolar disorder, major depression, and schizophrenia. Moreover, a number of recent studies have stressed the importance of cerebellar dysfunction in these same disorders. In the current study, we examined protein levels of the two GABA(B) receptor subunits GABBR1 and GABBR2 in lateral cerebella from a well-characterized cohort of subjects with schizophrenia (n=15), bipolar disorder (n=14), major depression (n=13) and healthy controls (n=12). We found significant reductions in protein for both GABBR1 and GABBR2 in lateral cerebella from subjects with schizophrenia, bipolar disorder and major depression when compared with controls. These results provide further evidence of GABAergic dysfunction in these three disorders as well as identify potential targets for therapeutic intervention.
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Affiliation(s)
- S. Hossein Fatemi
- Department of Psychiatry, Division of Neuroscience Research, University of Minnesota Medical School, 420 Delaware St SE, MMC 392, Minneapolis, MN 55455
- Department of Pharmacology, University of Minnesota Medical School, 310 Church St. SE, Minneapolis, MN 55455
- Department of Neuroscience, University of Minnesota Medical School, 310 Church St. SE, Minneapolis, MN 55455
| | - Timothy D. Folsom
- Department of Psychiatry, Division of Neuroscience Research, University of Minnesota Medical School, 420 Delaware St SE, MMC 392, Minneapolis, MN 55455
| | - Paul D. Thuras
- VA Medical Center, Department of Psychiatry, 1 Veterans Drive, Minneapolis, MN 55417
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Minimal Dose for Severe Poisoning and Influencing Factors in Acute Human Clozapine Intoxication. Clin Neuropharmacol 2010; 33:230-4. [DOI: 10.1097/wnf.0b013e3181f0ec55] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Zunner D, Deschermeier C, Kornau HC. GABA(B) receptor subunit 1 binds to proteins affected in 22q11 deletion syndrome. Biochem Biophys Res Commun 2010; 393:185-9. [PMID: 20036641 DOI: 10.1016/j.bbrc.2009.12.120] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2009] [Accepted: 12/20/2009] [Indexed: 01/08/2023]
Abstract
GABA(B) receptors mediate slow inhibitory effects of the neurotransmitter gamma-aminobutyric acid (GABA) on synaptic transmission in the central nervous system. They function as heterodimeric G-protein-coupled receptors composed of the seven-transmembrane domain proteins GABA(B1) and GABA(B2), which are linked through a coiled-coil interaction. The ligand-binding subunit GABA(B1) is at first retained in the endoplasmic reticulum and is transported to the cell surface only upon assembly with GABA(B2). Here, we report that GABA(B1), via the coiled-coil domain, can also bind to soluble proteins of unknown function, that are affected in 22q11 deletion/DiGeorge syndrome and are therefore referred to as DiGeorge critical region 6 (DGCR6). In transfected neurons the GABA(B1)-DGCR6 association resulted in a redistribution of both proteins into intracellular clusters. Furthermore, the C-terminus of GABA(B2) interfered with the novel interaction, consistent with heterodimer formation overriding transient DGCR6-binding to GABA(B1). Thus, sequential coiled-coil interactions may direct GABA(B1) into functional receptors.
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Affiliation(s)
- Dagmar Zunner
- Center for Molecular Neurobiology, University of Hamburg, Germany
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Nitsche MA, Monte-Silva K, Kuo MF, Paulus W. Dopaminergic Impact on Cortical Excitability in Humans. Rev Neurosci 2010; 21:289-98. [DOI: 10.1515/revneuro.2010.21.4.289] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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Brain and disease: the long path to discovery and treatment. Clin Pharmacol Ther 2009; 86:343-6. [PMID: 19763109 DOI: 10.1038/clpt.2009.168] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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