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Aishwarya R, Abdullah CS, Morshed M, Remex NS, Bhuiyan MS. Sigmar1's Molecular, Cellular, and Biological Functions in Regulating Cellular Pathophysiology. Front Physiol 2021; 12:705575. [PMID: 34305655 PMCID: PMC8293995 DOI: 10.3389/fphys.2021.705575] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2021] [Accepted: 06/07/2021] [Indexed: 12/11/2022] Open
Abstract
The Sigma 1 receptor (Sigmar1) is a ubiquitously expressed multifunctional inter-organelle signaling chaperone protein playing a diverse role in cellular survival. Recessive mutation in Sigmar1 have been identified as a causative gene for neuronal and neuromuscular disorder. Since the discovery over 40 years ago, Sigmar1 has been shown to contribute to numerous cellular functions, including ion channel regulation, protein quality control, endoplasmic reticulum-mitochondrial communication, lipid metabolism, mitochondrial function, autophagy activation, and involved in cellular survival. Alterations in Sigmar1’s subcellular localization, expression, and signaling has been implicated in the progression of a wide range of diseases, such as neurodegenerative diseases, ischemic brain injury, cardiovascular diseases, diabetic retinopathy, cancer, and drug addiction. The goal of this review is to summarize the current knowledge of Sigmar1 biology focusing the recent discoveries on Sigmar1’s molecular, cellular, pathophysiological, and biological functions.
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Affiliation(s)
- Richa Aishwarya
- Department of Molecular and Cellular Physiology, Louisiana State University Health Sciences Center-Shreveport, Shreveport, LA, United States
| | - Chowdhury S Abdullah
- Department of Pathology and Translational Pathobiology, Louisiana State University Health Sciences Center-Shreveport, Shreveport, LA, United States
| | - Mahboob Morshed
- Department of Pathology and Translational Pathobiology, Louisiana State University Health Sciences Center-Shreveport, Shreveport, LA, United States
| | - Naznin Sultana Remex
- Department of Molecular and Cellular Physiology, Louisiana State University Health Sciences Center-Shreveport, Shreveport, LA, United States
| | - Md Shenuarin Bhuiyan
- Department of Molecular and Cellular Physiology, Louisiana State University Health Sciences Center-Shreveport, Shreveport, LA, United States.,Department of Pathology and Translational Pathobiology, Louisiana State University Health Sciences Center-Shreveport, Shreveport, LA, United States
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Abdullah CS, Alam S, Aishwarya R, Miriyala S, Panchatcharam M, Bhuiyan MAN, Peretik JM, Orr AW, James J, Osinska H, Robbins J, Lorenz JN, Bhuiyan MS. Cardiac Dysfunction in the Sigma 1 Receptor Knockout Mouse Associated With Impaired Mitochondrial Dynamics and Bioenergetics. J Am Heart Assoc 2018; 7:e009775. [PMID: 30371279 PMCID: PMC6474981 DOI: 10.1161/jaha.118.009775] [Citation(s) in RCA: 50] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/14/2018] [Accepted: 09/10/2018] [Indexed: 12/21/2022]
Abstract
Background The Sigma 1 receptor (Sigmar1) functions as an interorganelle signaling molecule and elicits cytoprotective functions. The presence of Sigmar1 in the heart was first reported on the basis of a ligand-binding assay, and all studies to date have been limited to pharmacological approaches using less-selective ligands for Sigmar1. However, the physiological function of cardiac Sigmar1 remains unknown. We investigated the physiological function of Sigmar1 in regulating cardiac hemodynamics using the Sigmar1 knockout mouse (Sigmar1-/-). Methods and Results Sigmar1-/- hearts at 3 to 4 months of age showed significantly increased contractility as assessed by left ventricular catheterization with stimulation by increasing doses of a β1-adrenoceptor agonist. Noninvasive echocardiographic measurements were also used to measure cardiac function over time, and the data showed the development of cardiac contractile dysfunction in Sigmar1 -/- hearts as the animals aged. Histochemistry demonstrated significant cardiac fibrosis, collagen deposition, and increased periostin in the Sigmar1 -/- hearts compared with wild-type hearts. Ultrastructural analysis of Sigmar1-/- cardiomyocytes revealed an irregularly shaped, highly fused mitochondrial network with abnormal cristae. Mitochondrial size was larger in Sigmar1-/- hearts, resulting in decreased numbers of mitochondria per microscopic field. In addition, Sigmar1-/- hearts showed altered expression of mitochondrial dynamics regulatory proteins. Real-time oxygen consumption rates in isolated mitochondria showed reduced respiratory function in Sigmar1-/- hearts compared with wild-type hearts. Conclusions We demonstrate a potential function of Sigmar1 in regulating normal mitochondrial organization and size in the heart. Sigmar1 loss of function led to mitochondrial dysfunction, abnormal mitochondrial architecture, and adverse cardiac remodeling, culminating in cardiac contractile dysfunction.
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Affiliation(s)
- Chowdhury S. Abdullah
- Department of Pathology and Translational PathobiologyLouisiana State University Health Sciences CenterShreveportLA
| | - Shafiul Alam
- Department of Pathology and Translational PathobiologyLouisiana State University Health Sciences CenterShreveportLA
| | - Richa Aishwarya
- Department of Molecular and Cellular PhysiologyLouisiana State University Health Sciences CenterShreveportLA
| | - Sumitra Miriyala
- Department of Cellular Biology and AnatomyLouisiana State University Health Sciences CenterShreveportLA
| | - Manikandan Panchatcharam
- Department of Cellular Biology and AnatomyLouisiana State University Health Sciences CenterShreveportLA
| | | | - Jonette M. Peretik
- Department of Pathology and Translational PathobiologyLouisiana State University Health Sciences CenterShreveportLA
| | - A. Wayne Orr
- Department of Pathology and Translational PathobiologyLouisiana State University Health Sciences CenterShreveportLA
- Department of Molecular and Cellular PhysiologyLouisiana State University Health Sciences CenterShreveportLA
- Department of Cellular Biology and AnatomyLouisiana State University Health Sciences CenterShreveportLA
| | - Jeanne James
- Division of Pediatric CardiologyMedical College of WisconsinMilwaukeeWI
| | - Hanna Osinska
- Division of Molecular Cardiovascular BiologyCincinnati Children's HospitalCincinnatiOH
| | - Jeffrey Robbins
- Division of Molecular Cardiovascular BiologyCincinnati Children's HospitalCincinnatiOH
| | - John N. Lorenz
- Department of Molecular and Cellular PhysiologyUniversity of Cincinnati College of MedicineCincinnatiOH
| | - Md. Shenuarin Bhuiyan
- Department of Pathology and Translational PathobiologyLouisiana State University Health Sciences CenterShreveportLA
- Department of Molecular and Cellular PhysiologyLouisiana State University Health Sciences CenterShreveportLA
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Onaolapo OJ, Paul TB, Onaolapo AY. Comparative effects of sertraline, haloperidol or olanzapine treatments on ketamine-induced changes in mouse behaviours. Metab Brain Dis 2017; 32:1475-1489. [PMID: 28508340 DOI: 10.1007/s11011-017-0031-3] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/16/2017] [Accepted: 05/05/2017] [Indexed: 12/19/2022]
Abstract
Effects of sertraline, haloperidol or olanzapine administration on ketamine-induced behaviours in mice were examined. The aim was to ascertain the degree of reversal of such behaviours by sertraline, and compare its effectiveness to haloperidol and olanzapine. Ten-week old mice (N = 120) were equally divided into main groups; 1 (open-field, radial-arm maze and elevated plus maze {EPM} tests), and 2 (social interaction test). Mice in each main group were assigned into six groups of ten (n = 10) each. Group 1 received intraperitoneal (i.p) injection of vehicle, while groups 2-6 received i.p ketamine at 15 mg/kg daily for 10 days. From day 11 to 24, mice in group 1 (vehicle) were given distilled water (i.p at 2 ml/kg and oral at 10 ml/kg), group 2 (ketamine control) received daily i.p ketamine and oral distilled water; while animals in groups 3-6 received daily i.p. ketamine and oral haloperidol (4 mg/kg), olanzapine (2 mg/kg), or one of two doses of sertraline (SERT) (2.5 or 5 mg/kg), respectively. Treatments were administered daily, and behaviours assessed on days 11 and 24. Results showed that repeated ketamine administration caused hyperlocomotion, increased self-grooming, memory loss and social withdrawal. Administration of sertraline (both doses), haloperidol, and olanzapine reversed ketamine-induced behavioural changes. However, in the EPM, sertraline and olanzapine were anxiolytic, while haloperidol was anxiogenic. Sertraline's effect on behaviours tested was comparable to olanzapine and better than haloperidol. In conclusion, this study shows that sertraline's ability to counteract ketamine-induced behavioural changes in mice is comparable to known antipsychotics.
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Affiliation(s)
- O J Onaolapo
- Department of Pharmacology, Ladoke Akintola University of Technology, Osogbo, Osun State, Nigeria.
| | - T B Paul
- Department of Anatomy, Ladoke Akintola University of Technology, Ogbomoso, Oyo State, Nigeria
| | - A Y Onaolapo
- Department of Anatomy, Ladoke Akintola University of Technology, Ogbomoso, Oyo State, Nigeria.
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Barnes TRE, Leeson VC, Paton C, Costelloe C, Simon J, Kiss N, Osborn D, Killaspy H, Craig TKJ, Lewis S, Keown P, Ismail S, Crawford M, Baldwin D, Lewis G, Geddes J, Kumar M, Pathak R, Taylor S. Antidepressant Controlled Trial For Negative Symptoms In Schizophrenia (ACTIONS): a double-blind, placebo-controlled, randomised clinical trial. Health Technol Assess 2017; 20:1-46. [PMID: 27094189 DOI: 10.3310/hta20290] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
BACKGROUND Negative symptoms of schizophrenia represent deficiencies in emotional responsiveness, motivation, socialisation, speech and movement. When persistent, they are held to account for much of the poor functional outcomes associated with schizophrenia. There are currently no approved pharmacological treatments. While the available evidence suggests that a combination of antipsychotic and antidepressant medication may be effective in treating negative symptoms, it is too limited to allow any firm conclusions. OBJECTIVE To establish the clinical effectiveness and cost-effectiveness of augmentation of antipsychotic medication with the antidepressant citalopram for the management of negative symptoms in schizophrenia. DESIGN A multicentre, double-blind, individually randomised, placebo-controlled trial with 12-month follow-up. SETTING Adult psychiatric services, treating people with schizophrenia. PARTICIPANTS Inpatients or outpatients with schizophrenia, on continuing, stable antipsychotic medication, with persistent negative symptoms at a criterion level of severity. INTERVENTIONS Eligible participants were randomised 1 : 1 to treatment with either placebo (one capsule) or 20 mg of citalopram per day for 48 weeks, with the clinical option at 4 weeks to increase the daily dosage to 40 mg of citalopram or two placebo capsules for the remainder of the study. MAIN OUTCOME MEASURES The primary outcomes were quality of life measured at 12 and 48 weeks assessed using the Heinrich's Quality of Life Scale, and negative symptoms at 12 weeks measured on the negative symptom subscale of the Positive and Negative Syndrome Scale. RESULTS No therapeutic benefit in terms of improvement in quality of life or negative symptoms was detected for citalopram over 12 weeks or at 48 weeks, but secondary analysis suggested modest improvement in the negative symptom domain, avolition/amotivation, at 12 weeks (mean difference -1.3, 95% confidence interval -2.5 to -0.09). There were no statistically significant differences between the two treatment arms over 48-week follow-up in either the health economics outcomes or costs, and no differences in the frequency or severity of adverse effects, including corrected QT interval prolongation. LIMITATIONS The trial under-recruited, partly because cardiac safety concerns about citalopram were raised, with the 62 participants recruited falling well short of the target recruitment of 358. Although this was the largest sample randomised to citalopram in a randomised controlled trial of antidepressant augmentation for negative symptoms of schizophrenia and had the longest follow-up, the power of statistical analysis to detect significant differences between the active and placebo groups was limited. CONCLUSION Although adjunctive citalopram did not improve negative symptoms overall, there was evidence of some positive effect on avolition/amotivation, recognised as a critical barrier to psychosocial rehabilitation and achieving better social and community functional outcomes. Comprehensive assessment of side-effect burden did not identify any serious safety or tolerability issues. The addition of citalopram as a long-term prescribing strategy for the treatment of negative symptoms may merit further investigation in larger studies. FUTURE WORK Further studies of the viability of adjunctive antidepressant treatment for negative symptoms in schizophrenia should include appropriate safety monitoring and use rating scales that allow for evaluation of avolition/amotivation as a discrete negative symptom domain. Overcoming the barriers to recruiting an adequate sample size will remain a challenge. TRIAL REGISTRATION European Union Drug Regulating Authorities Clinical Trials (EudraCT) number 2009-009235-30 and Current Controlled Trials ISRCTN42305247. FUNDING This project was funded by the NIHR Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 20, No. 29. See the NIHR Journals Library website for further project information.
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Affiliation(s)
- Thomas R E Barnes
- Centre for Mental Health, Imperial College London, London, UK.,West London Mental Health NHS Trust, London, UK
| | - Verity C Leeson
- Centre for Mental Health, Imperial College London, London, UK
| | - Carol Paton
- Centre for Mental Health, Imperial College London, London, UK.,Oxleas NHS Foundation Trust, Dartford, UK
| | - Céire Costelloe
- National Institute for Health Research (NIHR) Health Protection Research Unit in Healthcare Associated Infections and Antimicrobial Resistance, Imperial College London, London, UK
| | - Judit Simon
- Department of Health Economics, Centre for Public Health, Medical University of Vienna, Vienna, Austria
| | - Noemi Kiss
- Department of Health Economics, Centre for Public Health, Medical University of Vienna, Vienna, Austria
| | - David Osborn
- Division of Psychiatry, University College London, UK.,Camden and Islington NHS Foundation Trust, London, UK
| | - Helen Killaspy
- Division of Psychiatry, University College London, UK.,Camden and Islington NHS Foundation Trust, London, UK
| | - Tom K J Craig
- Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK
| | - Shôn Lewis
- Institute of Brain, Behaviour and Mental Health, University of Manchester, Manchester, UK
| | - Patrick Keown
- Northumberland Tyne and Wear NHS Foundation Trust, Newcastle upon Tyne, UK
| | - Shajahan Ismail
- Sheffield Health and Social Care NHS Foundation Trust, Sheffield, UK
| | - Mike Crawford
- Centre for Mental Health, Imperial College London, London, UK
| | - David Baldwin
- Mental Health Group, University of Southampton Faculty of Medicine, Southampton, UK
| | - Glyn Lewis
- Division of Psychiatry, University College London, UK.,Camden and Islington NHS Foundation Trust, London, UK
| | - John Geddes
- Department of Psychiatry, University of Oxford, Oxford, UK
| | - Manoj Kumar
- South Staffordshire and Shropshire Healthcare NHS Foundation Trust, Stafford, UK
| | - Rudresh Pathak
- Lincolnshire Partnership NHS Foundation Trust, Lincoln, UK
| | - Simon Taylor
- Derbyshire Healthcare NHS Foundation Trust, Derby, UK
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Schoonover KE, McCollum LA, Roberts RC. Protein Markers of Neurotransmitter Synthesis and Release in Postmortem Schizophrenia Substantia Nigra. Neuropsychopharmacology 2017; 42:540-550. [PMID: 27550734 PMCID: PMC5399235 DOI: 10.1038/npp.2016.164] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/29/2016] [Revised: 07/15/2016] [Accepted: 08/13/2016] [Indexed: 12/30/2022]
Abstract
The substantia nigra (SN) provides the largest dopaminergic input to the brain, projects to the striatum (the primary locus of action for antipsychotic medication), and receives GABAergic and glutamatergic inputs. This study used western blot analysis to compare protein levels of tyrosine hydroxylase (TH), glutamate decarboxylase (GAD67), and vesicular glutamate transporters (vGLUT1 and vGLUT2) in postmortem human SN in schizophrenia subjects (n=13) and matched controls (n=12). As a preliminary analysis, the schizophrenia group was subdivided by (1) treatment status: off medication (n=4) or on medication (n=9); or (2) treatment response: treatment resistant (n=5) or treatment responsive (n=4). The combined schizophrenia group had higher TH and GAD67 protein levels than controls (an increase of 69.6%, P=0.01 and 19.5%, P=0.004, respectively). When subdivided by medication status, these increases were found in the on-medication subjects (TH 88.3%, P=0.008; GAD67 40.6%, P=0.003). In contrast, unmedicated schizophrenia subjects had higher vGLUT2 levels than controls (an increase of 28.7%, P=0.041), but vGLUT2 levels were similar between medicated schizophrenia subjects and controls. Treatment-resistant subjects had significantly higher TH and GAD67 levels than controls (an increase of 121.0%, P=0.0003 and 58.7%, P=0.004, respectively). These data suggest increases in dopamine and GABA transmission in the SN in schizophrenia, with a potential relation to treatment and response.
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Affiliation(s)
- Kirsten E Schoonover
- Department of Psychology and Behavioral Neuroscience, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Lesley A McCollum
- Department of Psychiatry and Behavioral Neurobiology, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Rosalinda C Roberts
- Department of Psychiatry and Behavioral Neurobiology, University of Alabama at Birmingham, Birmingham, AL, USA
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Intracellular pathways of antipsychotic combined therapies: implication for psychiatric disorders treatment. Eur J Pharmacol 2013; 718:502-23. [PMID: 23834777 DOI: 10.1016/j.ejphar.2013.06.034] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2013] [Revised: 06/11/2013] [Accepted: 06/21/2013] [Indexed: 01/06/2023]
Abstract
Dysfunctions in the interplay among multiple neurotransmitter systems have been implicated in the wide range of behavioral, emotional and cognitive symptoms displayed by major psychiatric disorders, such as schizophrenia, bipolar disorder or major depression. The complex clinical presentation of these pathologies often needs the use of multiple pharmacological treatments, in particular (1) when monotherapy provides insufficient improvement of the core symptoms; (2) when there are concurrent additional symptoms requiring more than one class of medication and (3) in order to improve tolerability, by using two compounds below their individual dose thresholds to limit side effects. To date, the choice of drug combinations is based on empirical paradigm guided by clinical response. Nonetheless, several preclinical studies have demonstrated that drugs commonly used to treat psychiatric disorders may impact common intracellular target molecules (e.g. Akt/GSK-3 pathway, MAP kinases pathway, postsynaptic density proteins). These findings support the hypothesis that convergence at crucial steps of transductional pathways could be responsible for synergistic effects obtained in clinical practice by the co-administration of those apparently heterogeneous pharmacological compounds. Here we review the most recent evidence on the molecular crossroads in antipsychotic combined therapies with antidepressants, mood stabilizers, and benzodiazepines, as well as with antipsychotics. We first discuss clinical clues and efficacy of such combinations. Then we focus on the pharmacodynamics and on the intracellular pathways underpinning the synergistic, or concurrent, effects of each therapeutic add-on strategy, as well as we also critically appraise how pharmacological research may provide new insights on the putative molecular mechanisms underlying major psychiatric disorders.
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Is poor research the cause of the declining productivity of the pharmaceutical industry? An industry in need of a paradigm shift. Drug Discov Today 2012; 18:211-7. [PMID: 23131208 DOI: 10.1016/j.drudis.2012.10.010] [Citation(s) in RCA: 75] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2012] [Revised: 09/29/2012] [Accepted: 10/26/2012] [Indexed: 01/18/2023]
Abstract
For the past 20 years target-based drug discovery has been the main research paradigm used by the pharmaceutical industry and billions of dollars have been invested into this approach. However, recent industry data strongly indicate that the target-based approach is not an effective drug discovery paradigm and is likely to be the cause of the productivity crisis the industry is experiencing. However, from a theoretical and scientific perspective the target-based approach appears sound, so why is it not more successful? The purpose of this paper is first to analyse the real-life implementation of the target-based approach to identify possible reasons for the high failure rate and second to suggest changes to the drug discovery approach, which can improve productivity.
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Vulink NCC, Westenberg HGM, van Nieuwerburgh F, Deforce D, Fluitman SBAHA, Meinardi JSC, Denys D. Catechol-O-methyltranferase gene expression is associated with response to citalopram in obsessive-compulsive disorder. Int J Psychiatry Clin Pract 2012; 16:277-83. [PMID: 22414277 DOI: 10.3109/13651501.2011.653375] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
OBJECTIVE To determine whether polymorphisms of the dopamine D(2) receptor (DRD2) and catechol-O-methyl-transferase (COMT) receptor genes affect the efficacy of quetiapine addition to citalopram in patients with OCD. METHODS Sixty-four drug-free or drug-naïve patients meeting DSM-IV criteria for OCD were randomized to 10 weeks double-blind treatment with citalopram (60 mg/day) with quetiapine (300 -450 mg/day) or with placebo. The change from baseline to endpoint on the total Yale-Brown Obsessive-Compulsive Scale (Y-BOCS) and the response to treatment were the primary outcome measures. Response was defined as a 25% decrease in Y-BOCS score. Responders and nonresponders were stratified according to DRD2 TaqI A and COMT Val(158)Met genotypes. RESULTS No significant differences in genotype distribution or allele frequencies of the COMT or DRD2 receptor were found between responders and nonresponders to citalopram with quetiapine. However, nearly half of responders to citalopram with placebo carried the Met/Met (48%) genotype of the COMT polymorphism compared to none of the nonresponders (χ(2) = 10.06, df = 2, P = 0.007). CONCLUSIONS The Met allele load of the COMT receptor gene was associated with response to 10 weeks of treatment with citalopram in drug-free or drug-naïve OCD patients.
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Affiliation(s)
- Nienke C C Vulink
- Department of Psychiatry, AMC, University of Amsterdam, Amsterdam, The Netherlands
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Voronkov DN, Dovedova EL, Khudoerkov RM. Interactions between neurotransmitter systems in nigrostriatal structures of rat brain after long-term administration of reserpine and haloperidol. NEUROCHEM J+ 2012. [DOI: 10.1134/s1819712412010102] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Intracerebroventricular administration of ouabain, a Na/K-ATPase inhibitor, activates tyrosine hydroxylase through extracellular signal-regulated kinase in rat striatum. Neurochem Int 2011; 59:779-86. [DOI: 10.1016/j.neuint.2011.08.011] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2011] [Revised: 08/08/2011] [Accepted: 08/10/2011] [Indexed: 01/28/2023]
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The involvement of GABA(A) receptor in the molecular mechanisms of combined selective serotonin reuptake inhibitor-antipsychotic treatment. Int J Neuropsychopharmacol 2011; 14:143-55. [PMID: 20181299 DOI: 10.1017/s1461145710000106] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
There is evidence that combining selective serotonin reuptake inhibitor (SSRI) antidepressant and antipsychotic drugs may improve negative symptoms in schizophrenia and resistant symptoms in obsessive-compulsive and affective disorders. To examine the mechanism of action of this treatment we investigated the molecular modulation of γ-aminobutyric acid-A (GABA(A)) receptor components and biochemical pathways associated with GABA(A) receptor function following administration of the SSRI fluvoxamine (Flu) combined with the first-generation antipsychotic haloperidol (Hal) and compared it to the individual drugs and the atypical antipsychotic clozapine (Clz). We analysed prefrontal cortices of Sprague-Dawley rats injected intraperitoneally (i.p.) with the combination of Flu (10 mg/kg) and Hal (1 mg/kg), each drug alone, or Clz (10 mg/kg) after 30 min and 1 h. We found that haloperidol plus fluvoxamine (Hal-Flu) co-administration, and Clz, decreased the level of GABAAβ2/3 receptor subunit in the cytosolic fraction, and increased it in the membrane compartment in rat PFC. Flu or Hal alone did not produce changes in GABAAβ2/3 receptor protein expression. Additionally, Hal-Flu and Clz regulated molecular signalling pathways that modulate GABA(A) receptor function, including protein kinase C (PKC) and extracellular signal-regulated kinase-2 (ERK2). In primary cortical culture, short-term treatment (15 min) with Hal-Flu combination and Clz increased GABAAβ subunit phosphorylation levels. Pretreatment of the cells with PKC inhibitor abolished the effect of the combined treatment, or Clz on phosphorylation of GABA(A) receptor. Inhibition of ERK2 did not alter the effect of drugs on GABA(A) receptor phosphorylation levels. Our findings provide evidence that the combined treatment regulates GABA(A) receptor function and does so via a PKC-dependent pathway.
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Molecular mechanisms underlying synergistic effects of SSRI–antipsychotic augmentation in treatment of negative symptoms in schizophrenia. J Neural Transm (Vienna) 2009; 116:1529-41. [DOI: 10.1007/s00702-009-0255-4] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2008] [Accepted: 06/05/2009] [Indexed: 01/08/2023]
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Silver H, Chertkow Y, Weinreb O, Danovich L, Youdim M. Multifunctional pharmacotherapy: what can we learn from study of selective serotonin reuptake inhibitor augmentation of antipsychotics in negative-symptom schizophrenia? Neurotherapeutics 2009; 6:86-93. [PMID: 19110201 PMCID: PMC5084258 DOI: 10.1016/j.nurt.2008.10.034] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Many patients suffering from major psychiatric disorders do not respond adequately to monotherapy and require additional drugs. To date, there are no objective guidelines for deciding which combination may be effective, and the choice is based on previous clinical experience and on trial and error. Even when combination drugs are effective, the biochemical mechanisms responsible for the value-added effect are unknown. Understanding the mechanism of such synergism may provide a rational basis for choosing drug combinations and for developing more effective drugs. In schizophrenia, negative symptoms respond poorly to antipsychotics, but may improve when these are augmented with selective serotonin reuptake inhibitors (SSRI). This augmenting effect cannot be explained by summating the pharmacological effects of the individual drugs. We proposed that the study of SSRI augmentation can serve as a window to understanding the biochemical mechanisms of clinically effective drug synergism. In a series of studies we identified unique biochemical effects of the combination, different from each individual drug, and proposed that some of these are involved in mediating the clinical effect. Here we review some of the findings and propose that the mechanism of action involves regionally selective modulation of the GABA system. The evidence indicates that the SSRI antidepressant-antipsychotic combination may be a useful paradigm for studying therapeutically effective synergistic drug interactions in schizophrenia. Although as yet limited in scope, the findings of definable molecular targets for synergistic SSRI-antipsychotic interaction provide new directions to inform future research and provide novel bio-molecular targets for drug development.
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Affiliation(s)
- Henry Silver
- Molecular Neuropsychiatry Unit, Brain Behavior Laboratory, Shaar Menashe Mental Health Center, and Technion-Faculty of Medicine, Haifa 32000, Israel.
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14
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Serotonergic approaches in the development of novel antipsychotics. Neuropharmacology 2008; 55:1056-65. [DOI: 10.1016/j.neuropharm.2008.05.025] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2008] [Revised: 05/24/2008] [Accepted: 05/27/2008] [Indexed: 01/23/2023]
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