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Dell’Osso L, Bonelli C, Nardi B, Giovannoni F, Pronestì C, Cremone IM, Amatori G, Pini S, Carpita B. Rethinking Clozapine: Lights and Shadows of a Revolutionary Drug. Brain Sci 2024; 14:103. [PMID: 38275523 PMCID: PMC10813979 DOI: 10.3390/brainsci14010103] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2023] [Revised: 01/16/2024] [Accepted: 01/18/2024] [Indexed: 01/27/2024] Open
Abstract
The current literature globally highlights the efficacy of Clozapine in several psychiatric disorders all over the world, with an FDA indication for reducing the risk of repeated suicidal behavior in patients with schizophrenia or schizoaffective disorder. A growing field of research is also stressing a possible broader beneficial effect of Clozapine in promoting neuroprotection and neurotrophism. However, this drug is linked to several life-threatening side effects, such as agranulocytosis, myocarditis and seizures, that limit its use in daily clinical practice. For this work, a search was performed on PubMed using the terms "Clozapine indications", "Clozapine adverse effects", "Clozapine regenerative effects", and "Clozapine neuroplasticity" with the aim of reviewing the scientific literature on Clozapine's treatment indications, adverse effects and potential regenerative role. The results confirmed the efficacy of clozapine in clinical practice, although limited by its adverse effects. It appears crucial to raise awareness among clinicians about the potential benefits of using Clozapine, as well educating medical personnel about its risks and the early identification of possible adverse effects and their management.
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Affiliation(s)
| | - Chiara Bonelli
- Department of Clinical and Experimental Medicine, Section of Psychiatry, University of Pisa, 67 Via Roma, 56126 Pisa, Italy; (L.D.); (B.N.); (F.G.); (C.P.); (I.M.C.); (G.A.); (S.P.); (B.C.)
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2
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Shing N, Walker MC, Chang P. The Role of Aberrant Neural Oscillations in the Hippocampal-Medial Prefrontal Cortex Circuit in Neurodevelopmental and Neurological Disorders. Neurobiol Learn Mem 2022; 195:107683. [PMID: 36174886 DOI: 10.1016/j.nlm.2022.107683] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2022] [Revised: 09/09/2022] [Accepted: 09/20/2022] [Indexed: 11/30/2022]
Abstract
The hippocampus (HPC) and medial prefrontal cortex (mPFC) have well-established roles in cognition, emotion, and sensory processing. In recent years, interests have shifted towards developing a deeper understanding of the mechanisms underlying interactions between the HPC and mPFC in achieving these functions. Considerable research supports the idea that synchronized activity between the HPC and the mPFC is a general mechanism by which brain functions are regulated. In this review, we summarize current knowledge on the hippocampal-medial prefrontal cortex (HPC-mPFC) circuit in normal brain function with a focus on oscillations and highlight several neurodevelopmental and neurological disorders associated with aberrant HPC-mPFC circuitry. We further discuss oscillatory dynamics across the HPC-mPFC circuit as potentially useful biomarkers to assess interventions for neurodevelopmental and neurological disorders. Finally, advancements in brain stimulation, gene therapy and pharmacotherapy are explored as promising therapies for disorders with aberrant HPC-mPFC circuit dynamics.
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Affiliation(s)
- Nathanael Shing
- Department of Clinical and Experimental Epilepsy, Institute of Neurology, University College London, London, WC1N 3BG, UK; Department of Medicine, University of Central Lancashire, Preston, PR17BH, UK
| | - Matthew C Walker
- Department of Clinical and Experimental Epilepsy, Institute of Neurology, University College London, London, WC1N 3BG, UK
| | - Pishan Chang
- Department of Neuroscience, Physiology & Pharmacology, University College London, London, WC1E 6BT.
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3
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Apam-Castillejos DJ, Tendilla-Beltrán H, Vázquez-Roque RA, Vázquez-Hernández AJ, Fuentes-Medel E, García-Dolores F, Díaz A, Flores G. Second-generation antipsychotic olanzapine attenuates behavioral and prefrontal cortex synaptic plasticity deficits in a neurodevelopmental schizophrenia-related rat model. J Chem Neuroanat 2022; 125:102166. [PMID: 36156295 DOI: 10.1016/j.jchemneu.2022.102166] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2022] [Revised: 09/17/2022] [Accepted: 09/20/2022] [Indexed: 11/19/2022]
Abstract
Second-generation antipsychotics are the drugs of choice for the treatment of neurodevelopmental-related mental diseases such as schizophrenia. Despite the effectiveness of these drugs to ameliorate some of the symptoms of schizophrenia, specifically the positive ones, the mechanisms beyond their antipsychotic effect are still poorly understood. Specifically, second-generation antipsychotics are reported to have anti-inflammatory, antioxidant and neuroplastic properties. Using the neonatal ventral hippocampus lesion (nVHL) in the rat, an accepted schizophrenia-related model, we evaluated the effect of the second-generation antipsychotic olanzapine (OLZ) in the behavioral, neuroplastic, and neuroinflammatory alterations exhibited in the nVHL animals. OLZ corrected the hyperlocomotion and impaired working memory of the nVHL animals but failed to enhance social disturbances of these animals. In the prefrontal cortex (PFC), OLZ restored the pyramidal cell structural plasticity in the nVHL rats, enhancing the dendritic arbor length, the spinogenesis and the proportion of mature spines. Moreover, OLZ attenuated astrogliosis as well as some pro-inflammatory, oxidative stress, and apoptosis-related molecules in the PFC. These findings reinforce the evidence of anti-inflammatory, antioxidant, and neurotrophic mechanisms of second-generation antipsychotics in the nVHL schizophrenia-related model, which allows for the possibility of developing more specific drugs for this disorder and thus avoiding the side effects of current schizophrenia treatments.
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Affiliation(s)
| | | | | | | | - Estefania Fuentes-Medel
- Facultad de Ciencias Químicas (FCQ), Benemérita Universidad Autónoma de Puebla (BUAP), Mexico
| | - Fernando García-Dolores
- Instituto de Ciencias Forenses del Tribunal Superior de Justicia de la Ciudad de México (TSJCDMX), Mexico
| | - Alfonso Díaz
- Facultad de Ciencias Químicas (FCQ), Benemérita Universidad Autónoma de Puebla (BUAP), Mexico
| | - Gonzalo Flores
- Instituto de Fisiología, Benemérita Universidad Autónoma de Puebla (BUAP), Mexico.
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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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5
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Sasamori H, Ohmura Y, Yoshida T, Yoshioka M. Noradrenaline reuptake inhibition increases control of impulsive action by activating D1-like receptors in the infralimbic cortex. Eur J Pharmacol 2019; 844:17-25. [DOI: 10.1016/j.ejphar.2018.11.041] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2018] [Revised: 11/24/2018] [Accepted: 11/28/2018] [Indexed: 11/24/2022]
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6
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Shikanai H, Oshima N, Kawashima H, Kimura SI, Hiraide S, Togashi H, Iizuka K, Ohkura K, Izumi T. N-methyl-d-aspartate receptor dysfunction in the prefrontal cortex of stroke-prone spontaneously hypertensive rat/Ezo as a rat model of attention deficit/hyperactivity disorder. Neuropsychopharmacol Rep 2018; 38:61-66. [PMID: 30106260 PMCID: PMC7292284 DOI: 10.1002/npr2.12007] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2017] [Revised: 01/10/2018] [Accepted: 01/11/2018] [Indexed: 11/07/2022] Open
Abstract
AIM We previously reported that stroke-prone spontaneously hypertensive rat/Ezo (SHRSP/Ezo) has high validity as an attention deficit/hyperactivity disorder (AD/HD) animal model, based on its behavioral phenotypes, such as inattention, hyperactivity, and impulsivity. Fronto-cortical dysfunction is implicated in the pathogenesis of AD/HD. In this study, we investigated prefrontal cortex (PFC) function in SHRSP/Ezo rats by electrophysiological methods and radioreceptor assay. METHODS We recorded excitatory postsynaptic potential in layer V pyramidal neurons in the PFC by intracellular recording method to assess synaptic plasticity in the form of long-term potentiation (LTP). We also performed N-methyl-d-aspartate acid (NMDA) receptor binding assay in the PFC and hippocampus using radiolabeled NMDA receptor antagonist [3 H]MK-801. RESULTS Theta-burst stimulation induced LTP in the PFC of genetic control, WKY/Ezo, whereas failed to induce LTP in that of SHRSP/Ezo. The Kd value of [3 H]MK-801 binding for NMDA receptors in the PFC of SHRSP/Ezo was higher than in the WKY/Ezo. Neither the Bmax nor Kd of [3 H]MK-801 binding in the SHRSP/Ezo hippocampus was significantly different to WKY/Ezo. CONCLUSION These results suggest that the AD/HD animal model SHRSP/Ezo has NMDA receptor dysfunction in the PFC.
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Affiliation(s)
- Hiroki Shikanai
- Department of Pharmacology, Faculty of Pharmaceutical Sciences, Health Sciences University of Hokkaido, Kanazawa, Ishikari-Tobetsu, Japan
| | - Nobuhiro Oshima
- Department of Biophysical Sciences, Faculty of Pharmaceutical Sciences, Health Sciences University of Hokkaido, Kanazawa, Ishikari-Tobetsu, Japan
| | - Hidekazu Kawashima
- Department of Biophysical Sciences, Faculty of Pharmaceutical Sciences, Health Sciences University of Hokkaido, Kanazawa, Ishikari-Tobetsu, Japan
| | - Shin-Ichi Kimura
- Department of Pharmacology, Faculty of Pharmaceutical Sciences, Health Sciences University of Hokkaido, Kanazawa, Ishikari-Tobetsu, Japan
| | - Sachiko Hiraide
- Department of Pharmacology, Faculty of Pharmaceutical Sciences, Health Sciences University of Hokkaido, Kanazawa, Ishikari-Tobetsu, Japan
| | - Hiroko Togashi
- Department of Pharmacology, Faculty of Pharmaceutical Sciences, Health Sciences University of Hokkaido, Kanazawa, Ishikari-Tobetsu, Japan
| | - Kenji Iizuka
- Department of Pharmacology, Faculty of Pharmaceutical Sciences, Health Sciences University of Hokkaido, Kanazawa, Ishikari-Tobetsu, Japan
| | - Kazue Ohkura
- Department of Biophysical Sciences, Faculty of Pharmaceutical Sciences, Health Sciences University of Hokkaido, Kanazawa, Ishikari-Tobetsu, Japan
| | - Takeshi Izumi
- Department of Pharmacology, Faculty of Pharmaceutical Sciences, Health Sciences University of Hokkaido, Kanazawa, Ishikari-Tobetsu, Japan
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Rame M, Caudal D, Schenker E, Svenningsson P, Spedding M, Jay TM, Godsil BP. Clozapine counteracts a ketamine-induced depression of hippocampal-prefrontal neuroplasticity and alters signaling pathway phosphorylation. PLoS One 2017; 12:e0177036. [PMID: 28472198 PMCID: PMC5417651 DOI: 10.1371/journal.pone.0177036] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2017] [Accepted: 04/20/2017] [Indexed: 01/01/2023] Open
Abstract
Single sub-anesthetic doses of ketamine can exacerbate the symptoms of patients diagnosed with schizophrenia, yet similar ketamine treatments rapidly reduce depressive symptoms in major depression. Acute doses of the atypical antipsychotic drug clozapine have also been shown to counteract ketamine-induced psychotic effects. In the interest of understanding whether these drug effects could be modeled with alterations in neuroplasticity, we examined the impact of acutely-administered ketamine and clozapine on in vivo long-term potentiation (LTP) in the rat’s hippocampus-to-prefrontal cortex (H-PFC) pathway. We found that a low dose of ketamine depressed H-PFC LTP, whereas animals that were co-administrated the two drugs displayed LTP that was similar to a saline-treated control. To address which signaling molecules might mediate such effects, we also examined phosphorylation and total protein levels of GSK3β, GluA1, TrkB, ERK, and mTOR in prefrontal and hippocampal sub-regions. Among the statistically significant effects that were detected (a) both ketamine and clozapine increased the phosphorylation of Ser9-GSK3β throughout the prefrontal cortex and of Ser2481-mTOR in the dorsal hippocampus (DH), (b) clozapine increased the phosphorylation of Ser831-GluA1 throughout the prefrontal cortex and of Ser845-GluA1 in the ventral hippocampus, (c) ketamine treatment increased the phosphorylation of Thr202/Tyr204-ERK in the medial PFC (mPFC), and (d) clozapine treatment was associated with decreases in the phosphorylation of Tyr705-TrkB in the DH and of Try816-TrkB in the mPFC. Further analyses involving phosphorylation effect sizes also suggested Ser831-GluA1 in the PFC displayed the highest degree of clozapine-responsivity relative to ketamine. These results provide evidence for how ketamine and clozapine treatments affect neuroplasticity and signaling pathways in the stress-sensitive H-PFC network. They also demonstrate the potential relevance of H-PFC pathway neuroplasticity for modeling ketamine-clozapine interactions in regards to psychosis.
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Affiliation(s)
- Marion Rame
- Laboratoire de Physiopathologie des Maladies Psychiatriques, UMR_S894 Inserm, Centre de Psychiatrie et Neurosciences, Paris, France
- Université Paris Descartes, Sorbonne Paris Cité, Paris, France
| | - Dorian Caudal
- Department of Clinical Neuroscience, Center for Molecular Medicine, Karolinska Institute, Stockholm, Sweden
| | | | - Per Svenningsson
- Department of Clinical Neuroscience, Center for Molecular Medicine, Karolinska Institute, Stockholm, Sweden
| | - Michael Spedding
- Institut de Recherches Servier, Croissy-sur-Seine, France
- Spedding Research Solutions SAS, Le Vesinet, France
| | - Thérèse M. Jay
- Laboratoire de Physiopathologie des Maladies Psychiatriques, UMR_S894 Inserm, Centre de Psychiatrie et Neurosciences, Paris, France
- Université Paris Descartes, Sorbonne Paris Cité, Paris, France
| | - Bill P. Godsil
- Laboratoire de Physiopathologie des Maladies Psychiatriques, UMR_S894 Inserm, Centre de Psychiatrie et Neurosciences, Paris, France
- Université Paris Descartes, Sorbonne Paris Cité, Paris, France
- * E-mail:
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De Rossi P, Chiapponi C, Spalletta G. Brain Functional Effects of Psychopharmacological Treatments in Schizophrenia: A Network-based Functional Perspective Beyond Neurotransmitter Systems. Curr Neuropharmacol 2016; 13:435-44. [PMID: 26412063 PMCID: PMC4790396 DOI: 10.2174/1570159x13666150507223542] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Psychopharmacological treatments for schizophrenia have always been a matter of debate and a very important issue in public health given the chronic, relapsing and disabling nature of the disorder. A thorough understanding of the pros and cons of currently available pharmacological treatments for schizophrenia is critical to better capture the features of treatment-refractory clinical pictures and plan the developing of new treatment strategies. This review focuses on brain functional changes induced by antipsychotic drugs as assessed by modern functional neuroimaging techniques (i.e. fMRI, PET, SPECT, MRI spectroscopy). The most important papers on this topic are reviewed in order to draw an ideal map of the main functional changes occurring in the brain during antipsychotic treatment. This supports the hypothesis that a network-based perspective and a functional connectivity approach are needed to fill the currently existing gap of knowledge in the field of psychotropic drugs and their mechanisms of action beyond neurotransmitter systems.
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Affiliation(s)
| | | | - Gianfranco Spalletta
- Neuropsychiatry Laboratory, Department of Clinical and Behavioural Neurology, IRCCS Santa Lucia Foundation, Via Ardeatina, 306, 00179 Rome, Italy.
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Effects of Dopamine and Serotonin Systems on Modulating Neural Oscillations in Hippocampus-Prefrontal Cortex Pathway in Rats. Brain Topogr 2016; 29:539-51. [PMID: 26969669 DOI: 10.1007/s10548-016-0485-3] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2015] [Accepted: 03/07/2016] [Indexed: 10/22/2022]
Abstract
Theta and gamma oscillations are believed to play an important role in cognition and memory, and their phase coupling facilitates the information transmission in hippocampal-cortex network. In a rat model of chronic stress, the phase coupling of both theta and gamma oscillations between ventral hippocampal CA1 (vCA1) and medial prefrontal cortex (mPFC) was found to be disrupted, which was associated with the impaired synaptic plasticity in the pathway. However, little was known about the mechanisms underlying the process. In order to address this issue, both dopamine and serotonin as monoaminergic neurotransmitters were involved in this study, since they were crucial factors in pathological basis of depressive disorder. Local field potentials (LFPs) were recorded simultaneously at both vCA1 and mPFC regions under anesthesia, before and after the injection of dopamine D1 receptor antagonist and 5-HT1A receptor agonist, respectively. The results showed that the blockage of D1 receptor could lead to depression-like decrement on theta phase coupling. In addition, the activation of 5-HT1A receptor enhanced vCA1-mPFC coupling on gamma oscillations, and attenuated CA1 theta-fast gamma cross frequency coupling. These data suggest that the theta phase coupling between vCA1 and mPFC may be modulated by dopamine system that is an underlying mechanism of the cognitive dysfunction in depression. Besides, the serotonergic system is probably involved in the regulation of gamma oscillations coupling in vCA1-mPFC network.
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Price R, Salavati B, Graff-Guerrero A, Blumberger DM, Mulsant BH, Daskalakis ZJ, Rajji TK. Effects of antipsychotic D2 antagonists on long-term potentiation in animals and implications for human studies. Prog Neuropsychopharmacol Biol Psychiatry 2014; 54:83-91. [PMID: 24819820 PMCID: PMC4138225 DOI: 10.1016/j.pnpbp.2014.05.001] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/25/2014] [Revised: 04/29/2014] [Accepted: 05/01/2014] [Indexed: 10/25/2022]
Abstract
In people with schizophrenia, cognitive abilities - including memory - are strongly associated with functional outcome. Long-term potentiation (LTP) is a form of neuroplasticity that is believed to be the physiological basis for memory. It has been postulated that antipsychotic medication can impair long-term potentiation and cognition by altering dopaminergic transmission. Thus, a systematic review was performed in order to assess the relationship between antipsychotics and D2 antagonists on long-term potentiation. The majority of studies on LTP and antipsychotics have found that acute administration of antipsychotics was associated with impairments in LTP in wild-type animals. In contrast, chronic administration and acute antipsychotics in animal models of schizophrenia were not. Typical and atypical antipsychotics and other D2 antagonists behaved similarly, with the exception of clozapine and olanzapine. Clozapine caused potentiation independent of tetanization, while olanzapine facilitated tetanus-induced potentiation. These studies are limited in their ability to model the effects of antipsychotics in patients with schizophrenia as they were largely performed in wild-type animals as opposed to humans with schizophrenia, and assessed after acute rather than chronic treatment. Further studies using patients with schizophrenia receiving chronic antipsychotic treatment are needed to better understand the effects of these medications in this population.
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Affiliation(s)
- Rae Price
- Institute of Medical Science, Faculty of Medicine, University of Toronto,Temerty Centre for Therapeutic Brain Intervention, Centre for Addiction and Mental Health, Toronto
| | - Bahar Salavati
- Institute of Medical Science, Faculty of Medicine, University of Toronto,Temerty Centre for Therapeutic Brain Intervention, Centre for Addiction and Mental Health, Toronto
| | - Ariel Graff-Guerrero
- Institute of Medical Science, Faculty of Medicine, University of Toronto,Department of Psychiatry, Faculty of Medicine, University of Toronto,Geriatric Psychiatry Division, Centre for Addiction and Mental Health, Toronto,Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Toronto
| | - Daniel M. Blumberger
- Institute of Medical Science, Faculty of Medicine, University of Toronto,Department of Psychiatry, Faculty of Medicine, University of Toronto,Temerty Centre for Therapeutic Brain Intervention, Centre for Addiction and Mental Health, Toronto,Geriatric Psychiatry Division, Centre for Addiction and Mental Health, Toronto,Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Toronto
| | - Benoit H. Mulsant
- Institute of Medical Science, Faculty of Medicine, University of Toronto,Department of Psychiatry, Faculty of Medicine, University of Toronto,Geriatric Psychiatry Division, Centre for Addiction and Mental Health, Toronto,Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Toronto
| | - Zafiris J. Daskalakis
- Institute of Medical Science, Faculty of Medicine, University of Toronto,Department of Psychiatry, Faculty of Medicine, University of Toronto,Temerty Centre for Therapeutic Brain Intervention, Centre for Addiction and Mental Health, Toronto,Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Toronto
| | - Tarek K. Rajji
- Institute of Medical Science, Faculty of Medicine, University of Toronto,Department of Psychiatry, Faculty of Medicine, University of Toronto,Temerty Centre for Therapeutic Brain Intervention, Centre for Addiction and Mental Health, Toronto,Geriatric Psychiatry Division, Centre for Addiction and Mental Health, Toronto,Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Toronto,Corresponding author: 80 Workman Way, Room 6312, Toronto, Ontario, Canada M6J 1H4. Phone: +1 416 535 8501 x 33661. Fax: +1 416 583 1307.
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11
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Subanalgesic ketamine enhances morphine-induced antinociceptive activity without cortical dysfunction in rats. J Anesth 2013; 28:390-8. [DOI: 10.1007/s00540-013-1722-5] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2013] [Accepted: 09/20/2013] [Indexed: 12/26/2022]
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12
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Blot K, Bai J, Otani S. The effect of non-competitive NMDA receptor antagonist MK-801 on neuronal activity in rodent prefrontal cortex: an animal model for cognitive symptoms of schizophrenia. ACTA ACUST UNITED AC 2013; 107:448-51. [PMID: 23603055 DOI: 10.1016/j.jphysparis.2013.04.003] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2013] [Revised: 04/09/2013] [Accepted: 04/11/2013] [Indexed: 11/29/2022]
Abstract
Schizophrenia affects about 1% of the world population and is a major socio-economical problem in ours societies. Cognitive symptoms are particularly resistant to current treatments and are believed to be closely related to an altered function of prefrontal cortex (PFC). Particularly, abnormalities in the plasticity processes in the PFC are a candidate mechanism underlying cognitive symptoms, and the recent evidences in patients are in line with this hypothesis. Animal pharmacological models of cognitive symptoms, notably with non-competitive NMDA receptor antagonists such as MK-801, are commonly used to investigate the underlying cellular and molecular mechanisms of schizophrenia. However, it is still unknown whether in these animal models, impairments in plasticity of PFC neurons are present. In this article, we briefly summarize the current knowledge on the effect of non-competitive NMDA receptor antagonist MK-801 on medial PFC (mPFC) neuronal activity and then introduce a form of plasticity found after acute exposure to MK-801, which was accompanied by cognitive deficits. These observations suggest a potential correlation between cognitive deficits and the aberrant plasticity in the mPFC in the animal model of schizophrenia.
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Affiliation(s)
- Kevin Blot
- INSERM U952/CNRS UMR 7224, Université Pierre et Marie Curie, 9 quai Saint Bernard, 75252 Paris cedex 05, France.
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13
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D'Agostino A, Limosani I, Scarone S. The dreaming brain/mind: a role in understanding complex mental disorders? Front Psychiatry 2012; 3:3. [PMID: 22319501 PMCID: PMC3269040 DOI: 10.3389/fpsyt.2012.00003] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/25/2011] [Accepted: 01/09/2012] [Indexed: 11/18/2022] Open
Affiliation(s)
- Armando D'Agostino
- Department of Medicine, Surgery and Dentistry, Università degli Studi di Milano Milan, Italy
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Abstract
A variety of serotonin (5-HT) receptors, especially 5-HT(2A), 5-HT(1A), 5-HT(6), 5-HT(7), and 5-HT(2C), have been postulated to contribute to the mechanism of action of atypical antipsychotic drugs (APDs), i.e., APDs which cause fewer extrapyramidal side effects (EPS) at clinically optimal doses, in contrast with typical APDs, which are more likely to cause EPS. This advantage, rarely disputed, has made such drugs the preferred treatment for schizophrenia and other indications for APDs. These 5-HT receptors are still of interest as components of novel multireceptor or stand-alone APDs, and potentially to remediate cognitive deficits in schizophrenia. Almost all currently available atypical APDs are 5-HT(2A) receptor inverse agonists, as well as dopamine (DA) D(2) receptor antagonists or partial agonists. Amisulpride, an exceptional atypical APD, has 5-HT(7) antagonism to complement its DA D(2/3) antagonism. Some atypical APDs are also 5-HT(1A) partial agonists, 5-HT(6), or 5-HT(7) antagonists, or some combination of the above. 5-HT(2C) antagonism has been found to contribute to the metabolic side effects of some atypical APDs, whereas 5-HT(2C) agonists have potential as stand-alone APDs and/or cognitive enhancers. This review will provide an update of current preclinical and clinical evidence for the role of these five 5-HT receptors in the actions of current APDs and for the development of novel psychotropic drugs.
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Affiliation(s)
- Herbert Y Meltzer
- Department of Psychiatry and Behavioral Sciences, Northwestern Feinberg School of Medicine, Chicago, IL 60611, USA.
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Mouaffak F, Kebir O, Bellon A, Gourevitch R, Tordjman S, Viala A, Millet B, Jaafari N, Olié JP, Krebs MO. Association of an UCP4 (SLC25A27) haplotype with ultra-resistant schizophrenia. Pharmacogenomics 2011; 12:185-93. [PMID: 21332312 DOI: 10.2217/pgs.10.179] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
AIMS Neuronal uncoupling proteins are involved in the regulation of reactive oxygen species production and intracellular calcium homeostasis, and thus, play a neuroprotective role. In order to explore the potential consequences of neuronal uncoupling proteins variants we examined their association in a sample of Caucasian patients suffering from schizophrenia and phenotyped them according to antipsychotic response. MATERIALS & METHODS Using a case-control design, we compared the frequencies of 15 genetic variants spanning UCP2, UCP4 and UCP5 in 106 French Caucasian patients suffering from schizophrenia and 127 healthy controls. In addition, patients with schizophrenia who responded to antipsychotic treatment were compared with patients with ultra-resistant schizophrenia (URS). This latter population presented no clinical, social and/or occupational remission despite at least two periods of treatment with conventional or atypical antipsychotic drugs and also with clozapine. RESULTS There were no differences in the distribution of the respective alleles between URS and responding patients. However, one haplotype spanning UCP4 was found to be significantly under-represented in URS patients. This relationship remained significant after multiple testing corrections. CONCLUSION Although our sample is of limited size and not representative of schizophrenia as a whole, the association found between the URS group and the UCP4 haplotype is noteworthy as it may influence treatment outcome in schizophrenia.
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Affiliation(s)
- Fayçal Mouaffak
- INSERM, Laboratoire de Physiopathologie des Maladies Psychiatriques, U894 Centre de Psychiatrie et Neurosciences, Paris, France
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Kamiyama H, Matsumoto M, Otani S, Kimura SI, Shimamura KI, Ishikawa S, Yanagawa Y, Togashi H. Mechanisms underlying ketamine-induced synaptic depression in rat hippocampus-medial prefrontal cortex pathway. Neuroscience 2010; 177:159-69. [PMID: 21163337 DOI: 10.1016/j.neuroscience.2010.12.012] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2010] [Revised: 12/07/2010] [Accepted: 12/08/2010] [Indexed: 02/02/2023]
Abstract
The non-competitive N-methyl-D-aspartate NMDA receptor antagonist ketamine, a dissociative anesthetic capable of inducing analgesia, is known to have psychotomimetic actions, but the detailed mechanisms remain unclear because of its complex properties. The present study elucidated neural mechanisms of the effect of ketamine, at doses that exert psychotomimetic effects without anesthetic and analgesic effects, by evaluating cortical synaptic responses in vivo. Systemic administration (i.p.) of low (1 and 5 mg/kg), subanesthetic (25 mg/kg) and anesthetic (100 mg/kg) doses of ketamine dose-dependently decreased hippocampal stimulation-evoked potential in the medial prefrontal cortex (mPFC) in freely moving rats. The behavioral analysis assessed by prepulse inhibition (PPI) of acoustic startle response showed that ketamine (5 and 25 mg/kg, i.p.) produced PPI deficit. Thus, the psychotomimetic effects observed in ketamine-treated groups (5 and 25 mg/kg, i.p.) are associated with the induction of synaptic depression in the hippocampus-mPFC neural pathway. Based on these results, we further examined the underlying mechanisms of the ketamine-induced synaptic depression under anesthesia. Ketamine (5 and 25 mg/kg, i.p.) caused increases in dialysate dopamine in the mPFC in anesthetized rats. Moreover, the ketamine-induced decreases in the evoked potential, at the dose 5 mg/kg which has no anesthetic and analgesic effects, were indeed absent in dopamine-lesioned rats pretreated with 6-hydroxydopamine (6-OHDA; 150 μg/rat, i.c.v.). Ketamine (5 mg/kg, i.p.)-induced synaptic depression was blocked by pretreatment with dopamine D1 receptor antagonist SCH 23390 (10 μg/rat, i.c.v.) but not dopamine D2 receptor antagonist haloperidol (1.5 mg/kg, i.p.), suggesting that dopaminergic modulation mediated via D1 receptors are involved in the synaptic effects of ketamine. Furthermore, ketamine (5 mg/kg, i.p.)-induced synaptic depression was prevented also by GABAA receptor antagonist bicuculline (0.2 or 2 μg/rat, i.c.v.). These findings suggest that ketamine at the dose that exerts psychotomimetic symptoms depresses hippocampus-mPFC synaptic transmission through mechanisms involving dopaminergic modulation mediated via D1 receptors, which may lead to a net augmentation of synaptic inhibition mediated via GABAA receptors.
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Affiliation(s)
- H Kamiyama
- Department of Pharmacology, School of Pharmaceutical Sciences, Health Sciences University of Hokkaido, Ishikari-Tobetsu, 061-0293, Japan
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Lavergne F, Jay TM. A new strategy for antidepressant prescription. Front Neurosci 2010; 4:192. [PMID: 21151361 PMCID: PMC2995552 DOI: 10.3389/fnins.2010.00192] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2010] [Accepted: 11/01/2010] [Indexed: 11/16/2022] Open
Abstract
From our research and literature search we propose an understanding of the mechanism of action of antidepressants treatments (ADTs) that should lead to increase efficacy and tolerance. We understand that ADTs promote synaptic plasticity and neurogenesis. This promotion is linked with stimulation of dopaminergic receptors. Previous evidence shows that all ADTs (chemical, electroconvulsive therapy, repetitive transcranial magnetic stimulation, sleep deprivation) increase at least one monoamine neurotransmitter serotonin (5-HT), noradrenaline (NA) or dopamine (DA); this article focuses on DA release or turn-over in the frontal cortex. DA increased dopaminergic activation promotes synaptic plasticity with an inverted U shape dose–response curve. Specific interaction between DA and glutamate is mediated by D1 receptor subtypes and Glutamate (NMDA) receptors with neurotrophic factors likely to play a modulatory role. With the understanding that all ADTs have a common, final, DA-ergic stimulation that promotes synaptic plasticity we can predict that (1) AD efficiency is related to the compound strength for inducing DA-ergic stimulation. (2) ADT efficiency presents a therapeutic window that coincides with the inverted U shape DA response curve. (3) ADT delay of action is related to a “synaptogenesis and neurogenesis delay of action.” (4) The minimum efficient dose can be found by starting at a low dosage and increasing up to the patient response. (5) An increased tolerance requires a concomitant prescription of a few ADTs, with different or opposite adverse effects, at a very low dose. (6) ADTs could improve all diseases with cognitive impairments and synaptic depression by increasing synaptic plasticity and neurogenesis.
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Affiliation(s)
- Francis Lavergne
- Physiopathologie des Maladies Psychiatriques, Centre de Psychiatrie et Neurosciences, INSERM U894, Centre Hospitalier Sainte-Anne Paris, France
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Shohamy D, Mihalakos P, Chin R, Thomas B, Wagner AD, Tamminga C. Learning and generalization in schizophrenia: effects of disease and antipsychotic drug treatment. Biol Psychiatry 2010; 67:926-32. [PMID: 20034612 PMCID: PMC4023678 DOI: 10.1016/j.biopsych.2009.10.025] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/05/2009] [Revised: 09/24/2009] [Accepted: 10/13/2009] [Indexed: 11/30/2022]
Abstract
BACKGROUND Schizophrenia involves alterations in hippocampal function. The implications of these alterations for memory function in the illness remain poorly understood. Furthermore, it remains unknown how memory is impacted by drug treatments for schizophrenia. The goal of this study was to delineate specific memory processes that are disrupted in schizophrenia and explore how they are affected by medication. We specifically focus on memory generalization--the ability to flexibly generalize memories in novel situations. METHODS Individuals with schizophrenia (n = 56) and healthy control subjects (n = 20) were tested on a computerized memory generalization paradigm. Participants first engaged in trial-by-error associative learning. They were then asked to generalize what they learned by responding to novel stimulus combinations. Individuals with schizophrenia were tested on or off antipsychotic medication, using a between-subject design in order to eliminate concerns about learning-set effects. RESULTS Individuals with schizophrenia were selectively impaired in their ability to generalize knowledge, despite having intact learning and memory accuracy. This impairment was found only in individuals tested off medication. Individuals tested on medication generalized almost as well as healthy control subjects. This between-group difference was selective to memory generalization. CONCLUSIONS These findings suggest that individuals with schizophrenia have a selective alteration in the ability to flexibly generalize past experience toward novel learning environments. This alteration is unaccompanied by global memory impairments. Additionally, the results indicate a robust generalization difference on the basis of medication status. These results suggest that hippocampal abnormalities in schizophrenia might be alleviated with antipsychotic medication, with important implications for understanding adaptive memory-guided behavior.
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Affiliation(s)
- Daphna Shohamy
- Department of Psychology, Columbia University, New York, New York 10027, USA.
| | - Perry Mihalakos
- Department of Psychiatry, University of Texas Southwestern Medical School, Dallas TX
| | - Ronald Chin
- Department of Psychiatry, University of Texas Southwestern Medical School, Dallas TX
| | - Binu Thomas
- Department of Psychiatry, University of Texas Southwestern Medical School, Dallas TX
| | | | - Carol Tamminga
- Department of Psychiatry, University of Texas Southwestern Medical School, Dallas TX
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Ohmura Y, Izumi T, Yamaguchi T, Tsutsui-Kimura I, Yoshida T, Yoshioka M. The serotonergic projection from the median raphe nucleus to the ventral hippocampus is involved in the retrieval of fear memory through the corticotropin-releasing factor type 2 receptor. Neuropsychopharmacology 2010; 35:1271-8. [PMID: 20072117 PMCID: PMC3055345 DOI: 10.1038/npp.2009.229] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Several different studies have separately established that serotonin, corticotropin-releasing factor (CRF) receptors, and the hippocampus are involved in fear memory retrieval. The main aim of this study is to connect these separate studies. To assess the levels of anxiety/fear, we used the contextual fear-conditioning test and the elevated plus maze test as memory-dependent and memory-independent tasks, respectively. We injected CRF receptor antagonists or vehicle into the median raphe nucleus (MRN) 10 min before behavioral tests. As a result, 1000 ng of astressin 2B (CRF(2) receptor antagonist), but not 250 ng of antalarmin (CRF(1) receptor antagonist), significantly suppressed the expression rate of freezing behavior in the contextual fear-conditioning test. However, in the elevated plus maze test, there was no difference between astressin 2B-injected rats and saline-injected rats in the time spent in open arms. Neither the amount of exploratory behavior nor the moving distance in the EPM of astressin 2B-injected rats differed from that of vehicle-injected rats. Moreover, when we assessed the extracellular serotonin release in the ventral hippocampus in freely moving rats through in vivo microdialysis, it was shown that the blockade of the CRF(2) receptor in the MRN suppressed serotonin release in the ventral hippocampus during fear memory retrieval. These results indicated that endogenous CRF and/or related ligands that were released in the MRN could activate the CRF(2) receptor and stimulate serotonin release in the ventral hippocampus, thereby inducing fear memory retrieval.
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Affiliation(s)
- Yu Ohmura
- Department of Neuropharmacology, Hokkaido University Graduate School of Medicine, Sapporo, Japan,Department of Pharmacology, University of Michigan, Ann Arbor, MI, USA
| | - Takeshi Izumi
- Department of Neuropharmacology, Hokkaido University Graduate School of Medicine, Sapporo, Japan
| | - Taku Yamaguchi
- Department of Neuropharmacology, Hokkaido University Graduate School of Medicine, Sapporo, Japan
| | - Iku Tsutsui-Kimura
- Department of Neuropharmacology, Hokkaido University Graduate School of Medicine, Sapporo, Japan
| | - Takayuki Yoshida
- Department of Neuropharmacology, Hokkaido University Graduate School of Medicine, Sapporo, Japan
| | - Mitsuhiro Yoshioka
- Department of Neuropharmacology, Hokkaido University Graduate School of Medicine, Sapporo, Japan,Department of Neuropharmacology, Hokkaido University Graduate School of Medicine, N15 W7, Kita-ku, Sapporo, Hokkaido, 060-8638, Japan. Tel: +81 11 706 5059; Fax: +81 11 706 7872; E-mail:
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Hill SK, Bishop JR, Palumbo D, Sweeney JA. Effect of second-generation antipsychotics on cognition: current issues and future challenges. Expert Rev Neurother 2010; 10:43-57. [PMID: 20021320 DOI: 10.1586/ern.09.143] [Citation(s) in RCA: 162] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Generalized cognitive impairments are stable deficits linked to schizophrenia and key factors associated with functional disability in the disorder. Preclinical data suggest that second-generation antipsychotics could potentially reduce cognitive impairments; however, recent large clinical trials indicate only modest cognitive benefits relative to first-generation antipsychotics. This might reflect a limited drug effect in humans, a differential drug effect due to brain alterations associated with schizophrenia, or limited sensitivity of the neuropsychological tests for evaluating cognitive outcomes. New adjunctive procognitive drugs may be needed to achieve robust cognitive and functional improvement. Drug discovery may benefit from greater utilization of translational neurocognitive biomarkers to bridge preclinical and clinical proof-of-concept studies, to optimize assay sensitivity, enhance cost efficiency, and speed progress in drug development.
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Affiliation(s)
- S Kristian Hill
- Center for Cognitive Medicine (M/C 913), University of Illinois at Chicago, 912 South Wood Street, Suite 235, Chicago, IL 60612, USA.
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Goto Y, Yang CR, Otani S. Functional and dysfunctional synaptic plasticity in prefrontal cortex: roles in psychiatric disorders. Biol Psychiatry 2010; 67:199-207. [PMID: 19833323 DOI: 10.1016/j.biopsych.2009.08.026] [Citation(s) in RCA: 227] [Impact Index Per Article: 16.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/15/2009] [Revised: 08/19/2009] [Accepted: 08/20/2009] [Indexed: 12/12/2022]
Abstract
Prefrontal cortex (PFC) mediates an assortment of cognitive functions including working memory, behavioral flexibility, attention, and future planning. Unlike the hippocampus, where induction of synaptic plasticity in the network is well-documented in relation to long-term memory, cognitive functions mediated by the PFC have been thought to be independent of long-lasting neuronal adaptation of the network. Nonetheless, accumulating evidence suggests that prefrontal cortical neurons possess the cellular machinery of synaptic plasticity and exhibit lasting changes of neural activity associated with various cognitive processes. Moreover, deficits in the mechanisms of synaptic plasticity induction in the PFC might be involved in the pathophysiology of psychiatric and neurological disorders such as schizophrenia, drug addiction, mood disorders, and Alzheimer's disease.
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Affiliation(s)
- Yukiori Goto
- Department of Psychiatry, McGill University, Montreal, Quebec H3A 1A1, Canada.
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Clozapine inhibits strychnine-sensitive glycine receptors in rat hippocampal neurons. Brain Res 2009; 1278:27-33. [PMID: 19409375 DOI: 10.1016/j.brainres.2009.04.043] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2008] [Revised: 04/20/2009] [Accepted: 04/22/2009] [Indexed: 11/20/2022]
Abstract
Seizure is one kind of severe side effects during clozapine (Clo) treatment. However, the mechanism of seizure associated with Clo therapy is not completely clear. Strychnine-sensitive glycine receptors (GlyRs) play an important role in regulating the excitability in the hippocampus. In the present study, we investigated the effect of Clo on GlyRs in cultured hippocampal neurons of rats. Clo reversibly inhibited the glycine-induced chloride currents (I(Gly)) in a concentration-dependent manner. The half-maximal effect concentration (EC(50)) for glycine alone was 25.6+/-0.7 microM with the Hill coefficient 1.5+/-0.1; in the presence of Clo, the EC(50) and the Hill coefficient were 28.9+/-6.3 microM and 1.2+/-0.3 respectively, which were not significantly affected by Clo. In addition, Clo inhibition of I(Gly) was not influenced by blocking D(1) and D(2) dopamine receptors with haloperidol (Hal). Taken together, these results suggest that Clo is a non-competitive antagonist of GlyR independent of its activation of dopamine receptors, which may contribute to seizure associated with Clo therapy.
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