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Santa C, Rodrigues D, Coelho JF, Anjo SI, Mendes VM, Bessa-Neto D, Dunn MJ, Cotter D, Baltazar G, Monteiro P, Manadas B. Chronic treatment with D2-antagonist haloperidol leads to inhibitory/excitatory imbalance in striatal D1-neurons. Transl Psychiatry 2023; 13:312. [PMID: 37803004 PMCID: PMC10558446 DOI: 10.1038/s41398-023-02609-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/18/2023] [Revised: 09/18/2023] [Accepted: 09/20/2023] [Indexed: 10/08/2023] Open
Abstract
Striatal dysfunction has been implicated in the pathophysiology of schizophrenia, a disorder characterized by positive symptoms such as hallucinations and delusions. Haloperidol is a typical antipsychotic medication used in the treatment of schizophrenia that is known to antagonize dopamine D2 receptors, which are abundantly expressed in the striatum. However, haloperidol's delayed therapeutic effect also suggests a mechanism of action that may go beyond the acute blocking of D2 receptors. Here, we performed proteomic analysis of striatum brain tissue and found more than 400 proteins significantly altered after 30 days of chronic haloperidol treatment in mice, namely proteins involved in glutamatergic and GABAergic synaptic transmission. Cell-type specific electrophysiological recordings further revealed that haloperidol not only reduces the excitability of striatal medium spiny neurons expressing dopamine D2 receptors (D2-MSNs) but also affects D1-MSNs by increasing the ratio of inhibitory/excitatory synaptic transmission (I/E ratio) specifically onto D1-MSNs but not D2-MSNs. Therefore, we propose the slow remodeling of D1-MSNs as a mechanism mediating the delayed therapeutic effect of haloperidol over striatum circuits. Understanding how haloperidol exactly contributes to treating schizophrenia symptoms may help to improve therapeutic outcomes and elucidate the molecular underpinnings of this disorder.
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Affiliation(s)
- Cátia Santa
- CNC-Center for Neuroscience and Cell Biology, University of Coimbra, 3004-504, Coimbra, Portugal
- III - Institute of Interdisciplinary Research, University of Coimbra, 3030-789, Coimbra, Portugal
| | - Diana Rodrigues
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, Braga, Portugal
- ICVS/3B's-PT Government Associate Laboratory, Braga/Guimaraes, Portugal
| | - Joana F Coelho
- CNC-Center for Neuroscience and Cell Biology, University of Coimbra, 3004-504, Coimbra, Portugal
- Faculty of Medicine, University of Coimbra, Coimbra, Portugal
| | - Sandra I Anjo
- CNC-Center for Neuroscience and Cell Biology, University of Coimbra, 3004-504, Coimbra, Portugal
| | - Vera M Mendes
- CNC-Center for Neuroscience and Cell Biology, University of Coimbra, 3004-504, Coimbra, Portugal
| | - Diogo Bessa-Neto
- CICS-UBI - Health Sciences Research Centre, University of Beira Interior, Covilhã, Portugal
| | - Michael J Dunn
- Proteome Research Centre, UCD Conway Institute of Biomolecular and Biomedical Research, School of Medicine, and Medical Sciences, University College Dublin, Dublin, Ireland
| | - David Cotter
- RCSI Psychiatry, Royal College of Surgeons in Ireland, Education and Research Centre Beaumont, Dublin, Ireland
| | - Graça Baltazar
- CICS-UBI - Health Sciences Research Centre, University of Beira Interior, Covilhã, Portugal
| | - Patrícia Monteiro
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, Braga, Portugal.
- ICVS/3B's-PT Government Associate Laboratory, Braga/Guimaraes, Portugal.
- Department of Biomedicine, Faculty of Medicine, University of Porto, 4200-319, Porto, Portugal.
| | - Bruno Manadas
- CNC-Center for Neuroscience and Cell Biology, University of Coimbra, 3004-504, Coimbra, Portugal.
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Oh-Nishi A, Nagai Y, Seki C, Suhara T, Minamimoto T, Higuchi M. Imaging extra-striatal dopamine D2 receptors in a maternal immune activation rat model. Brain Behav Immun Health 2022; 22:100446. [PMID: 35496774 PMCID: PMC9043973 DOI: 10.1016/j.bbih.2022.100446] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2022] [Accepted: 03/04/2022] [Indexed: 11/28/2022] Open
Abstract
Maternal immune activation (MIA) is a risk factor for schizophrenia in the offspring. MIA in pregnant rodents can be induced by injection of synthetic polyriboinosinic-polyribocytidilic acid (Poly I:C), which causes decreased striatal dopamine D2 receptor (D2R) expression and behavioral dysfunction mediated by the dopaminergic system in the offspring. However, previous studies did not determine whether Poly I:C induced cortical dopamine D2R abnormality in an MIA rat model. In this study, we performed micro-positron emission tomography (micro-PET) in vivo imaging and ex vivo neurochemical analyses of cortical D2Rs in MIA. In the micro-PET analyses, the anterior cingulate cortex (ACC) region in the offspring showed significantly reduced binding potential for [11C]FLB457, a high affinity radio-ligand toward D2Rs. Neurochemical analysis showed reduction of D2Rs and augmentation of dopamine turnover in the ACC of the rat offspring. Thus, MIA induces dopaminergic dysfunction in the ACC of offspring, similar to the neuronal pathology reported in patients with schizophrenia. Maternal immune activation (MIA) is a risk factor for schizophrenia. Improving extra-striatal Dopamine D2 receptors(D2Rs) thought to be important for the treatment of schizophrenia. In vivo imaging showed that the anterior cingulate cortex region in MIA model rat had reduced D2Rs density. The findings were similar to those of several publications regarding patients with schizophrenia.
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Affiliation(s)
- Arata Oh-Nishi
- Department of Functional Brain Imaging, National Institutes for Quantum Science and Technology, Chiba, 263-8555, Japan
- Division of Immune-Neuropsychiatry, Faculty of Medicine, Shimane University, Shimane, 693-8501, Japan
- RESVO Inc., Kawasaki, 210-007, Japan
- Corresponding author. Department of Functional Brain Imaging, National Institutes for Quantum Science and Technology, Chiba, 263-8555 Japan.
| | - Yuji Nagai
- Department of Functional Brain Imaging, National Institutes for Quantum Science and Technology, Chiba, 263-8555, Japan
| | - Chie Seki
- Department of Functional Brain Imaging, National Institutes for Quantum Science and Technology, Chiba, 263-8555, Japan
| | - Tetsuya Suhara
- Department of Functional Brain Imaging, National Institutes for Quantum Science and Technology, Chiba, 263-8555, Japan
| | - Takafumi Minamimoto
- Department of Functional Brain Imaging, National Institutes for Quantum Science and Technology, Chiba, 263-8555, Japan
| | - Makoto Higuchi
- Department of Functional Brain Imaging, National Institutes for Quantum Science and Technology, Chiba, 263-8555, Japan
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Brocos-Mosquera I, Gabilondo AM, Meana JJ, Callado LF, Erdozain AM. Spinophilin expression in postmortem prefrontal cortex of schizophrenic subjects: Effects of antipsychotic treatment. Eur Neuropsychopharmacol 2021; 42:12-21. [PMID: 33257116 DOI: 10.1016/j.euroneuro.2020.11.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/15/2020] [Revised: 11/04/2020] [Accepted: 11/11/2020] [Indexed: 10/22/2022]
Abstract
Schizophrenia has been associated with alterations in neurotransmission and synaptic dysfunction. Spinophilin is a multifunctional scaffold protein that modulates excitatory synaptic transmission and dendritic spine morphology. Spinophilin can also directly interact with and regulate several receptors for neurotransmitters, such as dopamine D2 receptors, which play a role in the pathophysiology of schizophrenia and are targets of antipsychotics. Several studies have thus suggested an implication of spinophilin in schizophrenia. In the present study spinophilin protein expression was determined by western blot in the postmortem dorsolateral prefrontal cortex of 24 subjects with schizophrenia (12 antipsychotic-free and 12 antipsychotic-treated subjects) and 24 matched controls. Experiments were performed in synaptosomal membranes (SPM) and in postsynaptic density fractions (PSD). As previously reported, two specific bands for this protein were observed: an upper 120-130 kDa band and a lower 80-95 kDa band. The spinophilin lower band showed a significant decrease in schizophrenia subjects compared to matched controls, both in SPM and PSD fractions (-15%, p = 0.007 and -15%, p = 0.039, respectively). When schizophrenia subjects were divided by the presence or absence of antipsychotics in blood at death, the lower band showed a significant decrease in antipsychotic-treated schizophrenia subjects (-24%, p = 0.003 for SPM and -26%, p = 0.014 for PSD), but not in antipsychotic-free subjects, compared to their matched controls. These results suggest that antipsychotics could produce alterations in spinophilin expression that do not seem to be related to schizophrenia per se. These changes may underlie some of the side effects of antipsychotics.
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Affiliation(s)
- Iria Brocos-Mosquera
- Department of Pharmacology, University of the Basque Country, UPV/EHU, Spain; Centro de Investigación Biomédica en Red de Salud Mental (CIBERSAM), Spain
| | - Ane M Gabilondo
- Department of Pharmacology, University of the Basque Country, UPV/EHU, Spain; Centro de Investigación Biomédica en Red de Salud Mental (CIBERSAM), Spain; Biocruces Bizkaia Health Research Institute, Barakaldo, Bizkaia, Spain
| | - J Javier Meana
- Department of Pharmacology, University of the Basque Country, UPV/EHU, Spain; Centro de Investigación Biomédica en Red de Salud Mental (CIBERSAM), Spain; Biocruces Bizkaia Health Research Institute, Barakaldo, Bizkaia, Spain
| | - Luis F Callado
- Department of Pharmacology, University of the Basque Country, UPV/EHU, Spain; Centro de Investigación Biomédica en Red de Salud Mental (CIBERSAM), Spain; Biocruces Bizkaia Health Research Institute, Barakaldo, Bizkaia, Spain
| | - Amaia M Erdozain
- Department of Pharmacology, University of the Basque Country, UPV/EHU, Spain; Centro de Investigación Biomédica en Red de Salud Mental (CIBERSAM), Spain.
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Peris-Yague A, Kiemes A, Cash D, Cotel MC, Singh N, Vernon AC, Modinos G. Region-specific and dose-specific effects of chronic haloperidol exposure on [ 3H]-flumazenil and [ 3H]-Ro15-4513 GABA A receptor binding sites in the rat brain. Eur Neuropsychopharmacol 2020; 41:106-117. [PMID: 33153853 PMCID: PMC7731940 DOI: 10.1016/j.euroneuro.2020.10.004] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/15/2020] [Revised: 09/02/2020] [Accepted: 10/16/2020] [Indexed: 11/02/2022]
Abstract
Postmortem studies suggest that schizophrenia is associated with abnormal expression of specific GABAA receptor (GABAAR) α subunits, including α5GABAAR. Positron emission tomography (PET) measures of GABAAR availability in schizophrenia, however, have not revealed consistent alterations in vivo. Animal studies using the GABAAR agonist [3H]-muscimol provide evidence that antipsychotic drugs influence GABAAR availability, in a region-specific manner, suggesting a potential confounding effect of these drugs. No such data, however, are available for more recently developed subunit-selective GABAAR radioligands. To address this, we combined a rat model of clinically relevant antipsychotic drug exposure with quantitative receptor autoradiography. Haloperidol (0.5 and 2 mg/kg/day) or drug vehicle were administered continuously to adult male Sprague-Dawley rats via osmotic mini-pumps for 28 days. Quantitative receptor autoradiography was then performed postmortem using the GABAAR subunit-selective radioligand [3H]-Ro15-4513 and the non-subunit selective radioligand [3H]-flumazenil. Chronic haloperidol exposure increased [3H]-Ro15-4513 binding in the CA1 sub-field of the rat dorsal hippocampus (p<0.01; q<0.01; d=+1.3), which was not dose-dependent. [3H]-flumazenil binding also increased in most rat brain regions (p<0.05; main effect of treatment), irrespective of the haloperidol dose. These data confirm previous findings that chronic haloperidol exposure influences the specific binding of non-subtype selective GABAAR radioligands and is the first to demonstrate a potential effect of haloperidol on the binding of a α1/5GABAAR-selective radioligand. Although caution should be exerted when extrapolating results from animals to patients, our data support a view that exposure to antipsychotics may be a confounding factor in PET studies of GABAAR in the context of schizophrenia.
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Affiliation(s)
- Alba Peris-Yague
- Department of Neuroimaging, Institute of Psychiatry, Psychology and Neuroscience, King's College London, De Crespigny Park, London SE5 8AF, United Kingdom
| | - Amanda Kiemes
- Department of Psychosis Studies, Institute of Psychiatry, Psychology and Neuroscience, King's College London, De Crespingy Park, London SE5 8AF, United Kingdom
| | - Diana Cash
- Department of Neuroimaging, Institute of Psychiatry, Psychology and Neuroscience, King's College London, De Crespigny Park, London SE5 8AF, United Kingdom
| | - Marie-Caroline Cotel
- Department of Basic and Clinical Neuroscience, Institute of Psychiatry, Psychology and Neuroscience, King's College London, Maurice Wohl Clinical Neuroscience Institute, 5 Cutcombe Road, London SE5 9RT, United Kingdom
| | - Nisha Singh
- Department of Neuroimaging, Institute of Psychiatry, Psychology and Neuroscience, King's College London, De Crespigny Park, London SE5 8AF, United Kingdom
| | - Anthony C Vernon
- Department of Basic and Clinical Neuroscience, Institute of Psychiatry, Psychology and Neuroscience, King's College London, Maurice Wohl Clinical Neuroscience Institute, 5 Cutcombe Road, London SE5 9RT, United Kingdom; MRC Centre for Neurodevelopmental Disorders, King's College London, London, United Kingdom.
| | - Gemma Modinos
- Department of Neuroimaging, Institute of Psychiatry, Psychology and Neuroscience, King's College London, De Crespigny Park, London SE5 8AF, United Kingdom; Department of Psychosis Studies, Institute of Psychiatry, Psychology and Neuroscience, King's College London, De Crespingy Park, London SE5 8AF, United Kingdom; MRC Centre for Neurodevelopmental Disorders, King's College London, London, United Kingdom.
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Abstract
Over the past 15 years, postmortem studies of the corticolimbic system in subjects with bipolar disorder (BPD) have demonstrated a variety of abnormalities affecting the gamma aminobutyric acid (GABA)ergic system. Although some of the changes are similar to those seen in individuals with schizophrenia, there are pronounced differences in the regulation of complex networks of genes involved in the expression of GAD67, a key marker for functionally differentiated GABAergic interneurons. Overall, these changes vary not only according to diagnosis, but also subregion and layer, suggesting that the activity of GABA cells in complex neural circuits are differentially affected by the unique extrinsic and intrinsic inputs that they receive at different points along a circuit like the trisynaptic pathway. Our ability to understand the functional implications in terms of complex molecular changes will ultimately influence our ability to develop novel treatments for BPD.
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Benes FM. Increases of Calbindin-Containing Chandelier Cartridges in Schizophrenia: Fact or Artifact? Biol Psychiatry 2017; 82:4-5. [PMID: 28619251 DOI: 10.1016/j.biopsych.2017.05.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/03/2017] [Accepted: 05/03/2017] [Indexed: 11/18/2022]
Affiliation(s)
- Francine M Benes
- Harvard Brain Tissue Resource Center, McLean Hospital, Belmont, Massachusetts.
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Oh-Nishi A, Koga K, Maeda T, Suhara T. A possible serologic biomarker for maternal immune activation-associated neurodevelopmental disorders found in the rat models. Neurosci Res 2016; 113:63-70. [PMID: 27425770 DOI: 10.1016/j.neures.2016.07.003] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2016] [Revised: 06/21/2016] [Accepted: 07/07/2016] [Indexed: 12/26/2022]
Abstract
Epidemiological studies have shown that maternal infection during early pregnancy increases the risk of neurodevelopmental disorders (i.e., schizophrenia or autism) in offspring. Recently, diagnostic/stratification biomarkers for the maternal immune activation background in patients with neurodevelopmental disorders have been energetically searched for in the patient blood. Here, we report a novel serologic marker candidate for the disorders found in the maternal immune activation (MIA) rat model. Serum proteome analysis of the MIA rat showed that the immunoglobulin (Ig) light chain is reproducibly augmented. The Ig light chain in sera takes two forms - free form or bound to the Ig heavy chain. Only the former is an inflammatory disease marker, but pro-inflammatory cytokine levels in the sera of the MIA rats were below detectable limits of the ELISA protocol we used. We thereby carried out serum assays of Ig light chains and pro-inflammatory cytokines of commercially available schizophrenia patient sera for research. Although the number of samples was limited, we found augmentation of free Ig light chains but not pro-inflammatory cytokines in sporadic schizophrenia patient sera. Our findings suggest that Ig light chain assay of the schizophrenia/autism patient sera would be worthy to be validated in larger scale.
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Affiliation(s)
- Arata Oh-Nishi
- Department of Functional Brain Imaging, National Institute of Radiological Sciences, National Institutes for Quantum and Radiological Sciences and Technology, Chiba 263-8555, Japan.
| | - Kaori Koga
- Anatech Corporation, Tokyo 113-0034, Japan
| | - Tadakazu Maeda
- Professor Emeritus, Kitasato University, Kanagawa 252-0373, Japan
| | - Tetsuya Suhara
- Department of Functional Brain Imaging, National Institute of Radiological Sciences, National Institutes for Quantum and Radiological Sciences and Technology, Chiba 263-8555, Japan
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Abstract
In the past century, the finding of ventricular enlargement in structural brain imaging studies of schizophrenia has stimulated interest in the question of whether this disorder may involve an underlying neurodegenerative process. Recent microscopic investigations have revealed a subtle loss of neurons but no gliosis in several corticolimbic regions of schizophrenic brain, a pattern that is not consistent with a typical adult pattern of neuronal degeneration. The fact that a variety of histopathological changes have been found in cortical layer II of schizophrenic subjects has suggested that an early disturbance of neuronal migration may play an etiological role in this disorder. Overall, many investigators now consider schizophrenia to be a neurodevel opmental disorder in which a latent defect present from birth requires normal maturational changes in the brain to trigger the characteristic onset of illness during adolescence and early adulthood. The Neuroscientist 1:104-115, 1995
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Affiliation(s)
- Francine M. Benes
- Laboratory for Structural Neuroscience McLean Hospital
Belmont, Massachusetts Program in Neuroscience and Department of Psychiatry
Harvard Medical School Boston, Massachusetts
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Berretta S, Heckers S, Benes FM. Searching human brain for mechanisms of psychiatric disorders. Implications for studies on schizophrenia. Schizophr Res 2015; 167:91-7. [PMID: 25458567 PMCID: PMC4427537 DOI: 10.1016/j.schres.2014.10.019] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/15/2014] [Revised: 10/10/2014] [Accepted: 10/13/2014] [Indexed: 12/14/2022]
Abstract
In the past 25years, research on the human brain has been providing a clear path toward understanding the pathophysiology of psychiatric illnesses. The successes that have been accrued are matched by significant difficulties identifying and controlling a large number of potential confounding variables. By systematically and effectively accounting for unwanted variance in data from imaging and postmortem human brain studies, meaningful and reliable information regarding the pathophysiology of human brain disorders can be obtained. This perspective paper focuses on postmortem investigations to discuss some of the most challenging sources of variance, including diagnosis, comorbidity, substance abuse and pharmacological treatment, which confound investigations of the human brain.
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Affiliation(s)
- Sabina Berretta
- Translational Neuroscience Laboratory, McLean Hospital, 115 Mill St., Belmont, MA 02478, USA; Department of Psychiatry, Harvard Medical School, 25 Shattuck St., Boston, MA 02115, USA; Program in Neuroscience, Harvard Medical School, 25 Shattuck St., Boston, MA 02115, USA.
| | - Stephan Heckers
- Department of Psychiatry, Vanderbilt University. 161 21st Ave S. #T1217 Nashville, TN, USA
| | - Francine M. Benes
- Dept. of Psychiatry, Harvard Medical School, 25 Shattuck St, Boston, MA 02115, USA,Program in Neuroscience, Harvard Medical School, 25 Shattuck St, Boston, MA 02115, USA,Program in Structural and Molecular Neuroscience, 115 Mill St. Belmont MA, 02478, USA
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10
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Association study of GABAA α2 receptor subunit gene variants in antipsychotic-associated weight gain. J Clin Psychopharmacol 2015; 35:7-12. [PMID: 25514066 DOI: 10.1097/jcp.0000000000000261] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Schizophrenia treatment has been hampered by undesirable adverse effects, including weight gain and associated complications. Recent candidate gene studies have been exploring the appetite regulation pathways in antipsychotic-associated weight gain (AAWG) with some promising leads. Genome-wide association studies of obesity have pointed to a number of potential candidate genes, such as MC4R, that were later found to be shared with AAWG. GABAA α2 receptor subunit (GABRA2) was another potential candidate gene for obesity from genome-wide association studies; however, it has not been explored in AAWG. We examined 9 single nucleotide polymorphisms across the GABRA2 gene. Prospective weight change was assessed for a total of 160 schizophrenia patients of European ancestry. The rs279858 marker was associated with percent weight change, with the patients homozygous for the TT genotype experiencing higher percentage weight gain on average than the C allele carriers (P = 0.009). When we performed the analysis considering each clinical site using a meta-analytic method, the results remained statistically significant (P = 1.4e-4). These findings became even more significant when we considered only patients taking clozapine or olanzapine, the 2 medications with higher risk for weight gain (P < 1e-10). GABRA2 genetic variants may play a role in predicting AAWG. However, replication in larger and independent samples is required.
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Konopaske GT, Bolo NR, Basu AC, Renshaw PF, Coyle JT. Time-dependent effects of haloperidol on glutamine and GABA homeostasis and astrocyte activity in the rat brain. Psychopharmacology (Berl) 2013; 230:57-67. [PMID: 23660600 PMCID: PMC3797182 DOI: 10.1007/s00213-013-3136-3] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/02/2012] [Accepted: 04/28/2013] [Indexed: 10/26/2022]
Abstract
RATIONALE Schizophrenia is a severe, persistent, and fairly common mental illness. Haloperidol is widely used and is effective against the symptoms of psychosis seen in schizophrenia. Chronic oral haloperidol administration decreased the number of astrocytes in the parietal cortex of macaque monkeys (Konopaske et al., Biol Psych 63:759-765, 2008). Since astrocytes play a key role in glutamate metabolism, chronic haloperidol administration was hypothesized to modulate astrocyte metabolic function and glutamate homeostasis. OBJECTIVES This study investigated the effects of chronic haloperidol administration on astrocyte metabolic activity and glutamate, glutamine, and GABA homeostasis. METHODS We used ex vivo ¹³C magnetic resonance spectroscopy along with high-performance liquid chromatography after [1-¹³C]glucose and [1,2-¹³C]acetate administration to analyze forebrain tissue from rats administered oral haloperidol for 1 or 6 months. RESULTS Administration of haloperidol for 1 month produced no changes in ¹³C labeling of glutamate, glutamine, or GABA, or in their total levels. However, a 6-month haloperidol administration increased ¹³C labeling of glutamine by [1,2-¹³C]acetate. Moreover, total GABA levels were also increased. Haloperidol administration also increased the acetate/glucose utilization ratio for glutamine in the 6-month cohort. CONCLUSIONS Chronic haloperidol administration in rats appears to increase forebrain GABA production along with astrocyte metabolic activity. Studies exploring these processes in subjects with schizophrenia should take into account the potential confounding effects of antipsychotic medication treatment.
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Affiliation(s)
- Glenn T. Konopaske
- Department of Psychiatry, Harvard Medical School, Boston, Massachusetts, USA
| | - Nicolas R. Bolo
- Department of Psychiatry, Harvard Medical School, Boston, Massachusetts, USA
| | - Alo C. Basu
- Department of Psychiatry, Harvard Medical School, Boston, Massachusetts, USA
| | - Perry F. Renshaw
- Department of Psychiatry, Harvard Medical School, Boston, Massachusetts, USA,Department of Psychiatry, University of Utah, Salt Lake City, Utah, USA
| | - Joseph T. Coyle
- Department of Psychiatry, Harvard Medical School, Boston, Massachusetts, USA
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Tayoshi S, Nakataki M, Sumitani S, Taniguchi K, Shibuya-Tayoshi S, Numata S, Iga JI, Ueno SI, Harada M, Ohmori T. GABA concentration in schizophrenia patients and the effects of antipsychotic medication: a proton magnetic resonance spectroscopy study. Schizophr Res 2010; 117:83-91. [PMID: 20022731 DOI: 10.1016/j.schres.2009.11.011] [Citation(s) in RCA: 87] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/17/2008] [Revised: 11/18/2009] [Accepted: 11/21/2009] [Indexed: 10/20/2022]
Abstract
Gamma-amino butyric acid (GABA) is thought to play a role in the pathophysiology of schizophrenia. High magnetic field proton magnetic resonance spectroscopy ((1)H-MRS) provides a reliable measurement of GABA in specific regions of the brain. This study measured GABA concentration in the anterior cingulate cortex (ACC) and in the left basal ganglia (ltBG) in 38 patients with chronic schizophrenia and 29 healthy control subjects. There was no significant difference in GABA concentration between the schizophrenia patients and the healthy controls in either the ACC (1.36+/-0.45 mmol/l in schizophrenia patients and 1.52+/-0.54 mmol/l in control subjects) or the ltBG (1.13+/-0.26 mmol/l in schizophrenia patients and 1.18+/-0.20 mmol/l in control subjects). Among the right handed schizophrenia patients, the GABA concentration in the ltBG was significantly higher in patients taking typical antipsychotics (1.25+/-0.24 mmol/l) than in those taking atypical antipsychotics (1.03+/-0.24 mmol/l, p=0.026). In the ACC, the GABA concentration was negatively correlated with the dose of the antipsychotics (rs=-0.347, p=0.035). In the ltBG, the GABA concentration was positively correlated with the dose of the anticholinergics (rs=0.403, p=0.015). To the best of our knowledge, this is the first study to have directly measured GABA concentrations in schizophrenia patients using (1)H-MRS. Our results suggest that there are no differences in GABA concentrations in the ACC or the ltBG of schizophrenia patients compared to healthy controls. Antipsychotic medication may cause changes in GABA concentration, and atypical and typical antipsychotics may have differing effects. It is possible that medication effects conceal inherent differences in GABA concentrations between schizophrenia patients and healthy controls.
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Affiliation(s)
- Shin'Ya Tayoshi
- Department of Psychiatry, Course of Integrated Brain Sciences, Medical Informatics, Institute of Health Biosciences, The University of Tokushima Graduate School, Japan
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13
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Abstract
Schizophrenia is a disorder in which disturbances in the integration of emotion with cognition plays a central role and probably involves several different regions, including the dorsolateral prefrontal cortex, the rostral anterior cingulate cortex, the hippocampal formation, and basolateral amygdala (BLA). Recent brain imaging studies have reported changes in volume, whereas postmortem studies point to dysfunction of the GABA and glutamate systems in these regions. Microarray-based profiles indicate that complex changes in the expression of genes associated with synaptic transmission and ion channels are involved in GABA cell dysfunction in schizophrenics. Molecular abnormalities vary considerably on the basis of sector and layer, suggesting that the unique connectivity of intrinsic and extrinsic afferents may critical in regulating the activity of genes in specific subpopulations of GABA cells. Projections of the BLA may be of particular importance to the induction of abnormal circuitry in schizophrenia, as their ingrowth during late adolescence and early adulthood may help to 'trigger' the onset of illness in susceptible individuals. A preponderance of cellular and molecular abnormalities has been found in the stratum oriens (SO) of sectors CA3/2 in which BLA afferents provide a robust innervation. These observations have lead to the development of a rodent model for the study of abnormal circuitry in this disorder. For example, single-cell recordings in hippocampal slices exposed to increased activation from the BLA have shown decreases in GABA currents in pyramidal neurons in SO of CA3/2, but not CA1, and support the validity of this model. Overall, the postmortem studies of neural circuitry abnormalities in schizophrenia are beginning to implicate specific cellular, molecular, and electrophysiological mechanism in specific subtypes of cortical neurons defined by their afferent and efferent connectivity within key corticolimbic regions.
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Affiliation(s)
- Francine M Benes
- Program in Structural and Molecular Neuroscience, McLean Hospital, Belmont, MA, USA.
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14
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Benes FM, Lim B, Matzilevich D, Subburaju S, Walsh JP. Circuitry-based gene expression profiles in GABA cells of the trisynaptic pathway in schizophrenics versus bipolars. Proc Natl Acad Sci U S A 2008; 105:20935-40. [PMID: 19104056 PMCID: PMC2606901 DOI: 10.1073/pnas.0810153105] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2008] [Indexed: 01/22/2023] Open
Abstract
Significant reductions in GABAergic cell numbers and/or activity have been demonstrated in the hippocampus of subjects with schizophrenia and bipolar disorder. To understand how different subpopulations of interneurons are regulated, laser microdissection and gene expression profiling have been used to "deconstruct" the trisynaptic pathway, so that subtypes of GABA cells could be defined by their location in various layers of CA3/2 and CA1. The results suggest that the cellular endophenotypes for SZ and BD may be determined by multiple factors that include unique susceptibility genes for the respective disorders and altered integration among hippocampal GABA cells with extrinsic and intrinsic afferent fiber systems. The extensive and intricate data that has come from this study has provided insights into how a complex circuit, like the trisynaptic pathway, may be regulated in human hippocampus in both health and disease.
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Affiliation(s)
- Francine M Benes
- Program in Structural and Molecular Neuroscience, McLean Hospital, Belmont, MA 02478, USA.
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15
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Grund T, Teuchert-Noodt G, Busche A, Neddens J, Brummelte S, Moll GH, Dawirs RR. Administration of oral methylphenidate during adolescence prevents suppressive development of dopamine projections into prefrontal cortex and amygdala after an early pharmacological challenge in gerbils. Brain Res 2007; 1176:124-32. [PMID: 17900540 DOI: 10.1016/j.brainres.2007.06.107] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2007] [Revised: 06/21/2007] [Accepted: 06/30/2007] [Indexed: 12/14/2022]
Abstract
The enduring effects of postweaning subchronic methylphenidate (MP) treatment and/or previous early preweaning methamphetamine (MA) application on dopamine (DA) fiber density were investigated in multiple cortical and subcortical areas of the gerbil brain. The study aimed to explore three questions: (1) is the development of DA fiber innervation in control animals sensitive to a clinically relevant subchronic treatment with MP? (2) Is the development of DA fiber innervation in the forebrain altered by a single early MA challenge? (3) If so, might the subsequent institution of a therapeutically relevant MP application scheme interfere with such early induced alternative developmental trajectories for DA fiber innervation? For this purpose, gerbils pretreated both with saline and MA (50 mg/kg, i.p.) on day 14 received either H(2)O or MP (5 mg/kg) orally on days 30 to 60. On day 90, DA fibers were immunohistochemically detected and quantified. As a result, MP on its own did not have any significant influence on the postnatal development of the DA fiber systems, whereas it prevented a previously MA triggered suppressive development of DA fiber innervation in the prefrontal cortex and amygdala complex (30% less fiber innervation in both areas). Thus, MP prevented previously initiated miswiring of DA fibers from actually being implemented in the gerbil forebrain. During earlier studies, rather complex miswiring has been documented in response to an early preweaning MA challenge. This miswiring was associated with functional deficits resembling some of the symptoms of patients with ADHD. Therefore, morphogenetic properties of MP need further attention.
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Affiliation(s)
- Thorsten Grund
- Department of Neuroanatomy, Faculty of Biology, University of Bielefeld, Bielefeld, Germany
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16
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Benes FM, Gisabella B. Rat modeling for GABA defects in schizophrenia. ADVANCES IN PHARMACOLOGY (SAN DIEGO, CALIF.) 2006; 54:73-93. [PMID: 17175811 DOI: 10.1016/s1054-3589(06)54004-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Affiliation(s)
- Francine M Benes
- Program in Structural and Molecular Neuroscience, McLean Hospital, Belmont, Massachusetts, USA
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17
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Torrey EF, Barci BM, Webster MJ, Bartko JJ, Meador-Woodruff JH, Knable MB. Neurochemical markers for schizophrenia, bipolar disorder, and major depression in postmortem brains. Biol Psychiatry 2005; 57:252-60. [PMID: 15691526 DOI: 10.1016/j.biopsych.2004.10.019] [Citation(s) in RCA: 347] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/25/2004] [Revised: 09/29/2004] [Accepted: 10/28/2004] [Indexed: 10/26/2022]
Abstract
BACKGROUND Previous studies of postmortem neurochemical markers in severe psychiatric disorders have been carried out on different brain collections, making it difficult to compare results. METHODS One hundred RNA, protein, and other neurochemical markers were assessed in a single set of 60 postmortem brains (15 each with schizophrenia, bipolar disorder, major depression without psychosis, and unaffected control subjects) in relation to seven neurochemical systems. Quantitative measures of continuous variables for prefrontal, hippocampus, anterior cingulate, superior temporal cortex, or a combination of these were analyzed from published and unpublished studies by 56 research groups. RESULTS Before correcting for multiple comparisons, 23% of markers (23/100) were abnormal in one or more regions, with most indicating decreased expression. The largest percentage were associated with the developmental/synaptic (10/22) and gamma-aminobutyric acid (GABA; 3/7) systems. Bipolar disorder (20) and schizophrenia (19) had the most abnormalities, with a 65% overlap. When all brain areas were considered together and corrected for multiple comparisons, reelin, parvalbumin, and GAD67 were the most abnormal. CONCLUSIONS Confirming other studies, the GABA and developmental/synaptic neurochemical systems are promising areas for research on schizophrenia and bipolar disorder. Research should include tissue from both diseases, and additional brain areas should be assessed.
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Affiliation(s)
- E Fuller Torrey
- Stanley Medical Research Institute, Uniformed Services University of the Health Sciences, Bethesda, Maryland, USA.
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18
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Brake WG, Zhang TY, Diorio J, Meaney MJ, Gratton A. Influence of early postnatal rearing conditions on mesocorticolimbic dopamine and behavioural responses to psychostimulants and stressors in adult rats. Eur J Neurosci 2004; 19:1863-74. [PMID: 15078560 DOI: 10.1111/j.1460-9568.2004.03286.x] [Citation(s) in RCA: 243] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
While many experiment with drugs, relatively few individuals develop a true addiction. We hypothesized that, in rats, such individual differences in the actions of addictive drugs might be determined by postnatal rearing conditions. To test this idea, we investigated whether stimulant- and stress-induced activation of nucleus accumbens dopamine transmission and dopamine-dependent behaviours might differ among adults rats that had been either repeatedly subjected to prolonged maternal separation or a brief handling procedure or left undisturbed (non-handled) during the first 14 days of life. We found that, in comparison with their handled counterparts, maternally separated and non-handled animals are hyperactive when placed in a novel setting, display a dose-dependent higher sensitivity to cocaine-induced locomotor activity and respond to a mild stressor (tail-pinch) with significantly greater increases in nucleus accumbens dopamine levels. In addition, maternally separated animals were found to sensitize to the locomotor stimulant action of amphetamine when repeatedly stressed under conditions that failed to sensitize handled and non-handled animals. Finally, quantitative receptor autoradiography revealed a lower density of nucleus accumbens-core and striatal dopamine transporter sites in maternally separated animals. Interestingly, we also found greatly reduced D(3) dopamine receptor binding and mRNA levels in the nucleus accumbens-shell of handled animals. Together, these findings provide compelling evidence that disruptions in early postnatal rearing conditions can lead to profound and lasting changes in the responsiveness of mesocorticolimbic dopamine neurons to stress and psychostimulants, and suggest a neurobiological basis for individual differences in vulnerability to compulsive drug taking.
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Affiliation(s)
- Wayne G Brake
- Department of Psychology, University of California Santa Barbara, CA 93106, USA
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19
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Molina V, Reig S, Desco M, Gispert JD, Sanz J, Sarramea F, Pascau J, Benito C, Martínez-Lázaro R, Luque R, Aragües M, Misiego JM, Corral IL, Palomo T. Multimodal neuroimaging studies and neurodevelopment and neurodegeneration hypotheses of schizophrenia. Neurotox Res 2002; 4:437-451. [PMID: 12754158 DOI: 10.1080/10298420290031397] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
The interpretation of the huge number of results in schizophrenia research using neuroimaging is uncertain. However, the simultaneous use of complimentary data obtained with these techniques may yield more relevant information in this regard. In this paper we present a series of studies performed by our group in two schizophrenic samples with the use of structural (magnetic resonance imaging, MRI), functional [glucose positron emission tomography (PET) and N-acetyl-aspartate (NAA) magnetic resonance spectrocopy] and neurophysiological techniques (the P300 event-related potential). Transversal and longitudinal measurements were performed.The integrated vision of the results so obtained allows us to propose the hypothesis of a neurodevelopmentally determined state of prefrontal disinihibition, in which the degree of atrophy would directly relate to the metabolic rate. This state would already be present in the first stages of illness and could have neurotoxic consequences in the long term. This would explain the findings of an association between sulcal cerebrospinal fluid (CSF) and illness duration and decreased NAA levels in chronic but not in recent-onset cases. The prefrotnal disinhibition would overstimulate the limbic system and the hippocampus would become overactivated, the metabolic rate at this level being inversely related to P300 amplitude. Clozapine showed a more selective and intense action on that hyperactive metabolic tone than haloperidol.
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Affiliation(s)
- Vicente Molina
- Dept of Psychiatry, Hospital 12 de Octubre, Edificio de Medicina Comunitaria, Avda de Córdoba, km 5.4, 28041, Madrid, Spain
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20
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Abstract
OBJECTIVE We have analysed pharmacologically induced perturbation of functional and structural neurogenesis in the prefrontal cortex (PFC) and hippocampus. METHOD Juvenile gerbils received a single dose of methamphetamine (METH, 50 mg/kg, i.p.). In adults the following parameters were quantitatively investigated: prefrontal dopaminergic and GABAergic innervation densities (immunocytochemistry), morphogenesis of pyramidal cells (Golgi), dentate granule cell proliferation (BrdU-labelling), working memory and behavioural inhibition (delayed response, open-field). RESULT A single challenge of METH continuously suppresses granule cell proliferation in adult gerbils and initiates rewiring of neuronal networks in the PFC which run concurrently with the development of severe deficits in PFC-related behaviours. CONCLUSION It appears that a continuous remodelling of neuronal circuits is an inherent property of the brain, the biological significance of which seems to be to ascertain adaptive interaction between brain and environment. Learning more about drug-induced neuronal reorganization might be basic for understanding the genesis of psychotic conditions in the brain. This presentation is based both on own research and on a review of the literature.
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Affiliation(s)
- R R Dawirs
- University of Bielefeld, Faculty of Biology, Department of Neuroanatomy, Germany
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21
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Kalus P, Bondzio J, Federspiel A, Müller TJ, Zuschratter W. Cell-type specific alterations of cortical interneurons in schizophrenic patients. Neuroreport 2002; 13:713-7. [PMID: 11973476 DOI: 10.1097/00001756-200204160-00035] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
In the human brain, cortical GABAergic interneurons represent an important population of local circuit neurons responsible for the intrinsic modulation of neuronal information and have been supposed to be involved in the pathophysiology of schizophrenia. We conducted a quantitative study on the differentiated three-dimensional morphological structure of two types of parvalbumin-immunoreactive interneurons in the anterior cingulate cortex (ACC) of schizophrenic patients versus controls. While type A interneurons ('small bipolar cells') showed a significant reduction of their soma size in schizophrenics, type B interneurons ('small multipolar cells') of schizophrenic patients exhibited a marked decrease in the extent of their dendritic system. These results further support the assumption of a considerable significance of the ACC, an important limbic relay centre, for the etiopathogenesis of schizophrenic psychoses.
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Affiliation(s)
- Peter Kalus
- University Hospital of Clinical Psychiatry Bern, Bolligenstrasse 111, CH-3000 Bern 60, Switzerland
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22
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Murphy CA, Feldon J. Interactions between environmental stimulation and antipsychotic drug effects on forebrain c-fos activation. Neuroscience 2001; 104:717-30. [PMID: 11440804 DOI: 10.1016/s0306-4522(01)00110-5] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
The immediate-early gene product Fos is differentially induced in the rat brain by the antipsychotic drugs haloperidol and clozapine. It is often claimed that although both drugs induce Fos in the nucleus accumbens, haloperidol but not clozapine increases Fos-like immunoreactivity in the striatum, whereas clozapine but not haloperidol increases Fos-like immunoreactivity in prefrontal cortex. Investigations of antipsychotic drug effects on Fos have typically administered high doses with pronounced sedative effects to behaviorally naive animals. In the present study, we compared the effects of low doses of haloperidol (0.1 mg/kg) and clozapine (5 mg/kg) on Fos-like immunoreactivity in rats which were either behaviorally naive, exposed to a novel environment or tested for two-way active avoidance. We determined that haloperidol increased Fos in the striatum and nucleus accumbens regardless of testing condition whereas clozapine markedly reduced the induction of Fos by behavioral testing in these regions; moreover, haloperidol dramatically increased prefrontal cortical Fos expression in animals placed in a novel environment, but not in testing-naive controls. From these results we suggest that antipsychotic drug-induced patterns of Fos expression in the rat are highly dependent on animals' concurrent behavioral status, perhaps reflecting neuroanatomically specific interactions between antipsychotic drugs and environmental stressors which also may occur in the schizophrenic condition.
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Affiliation(s)
- C A Murphy
- Behavioral Neurobiology Laboratory, Swiss Federal Institute of Technology (ETH-Zurich), Schorenstrasse 16, CH-8603, Schwerzenbach, Switzerland.
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23
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Berretta S, Munno DW, Benes FM. Amygdalar activation alters the hippocampal GABA system: "partial" modelling for postmortem changes in schizophrenia. J Comp Neurol 2001; 431:129-38. [PMID: 11169995 DOI: 10.1002/1096-9861(20010305)431:2<129::aid-cne1060>3.0.co;2-6] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Abnormalities in amygdala and hippocampus have been shown to coexist in schizophrenia (SZ). In the hippocampus, compelling evidence suggests that a disruption of GABA neurotransmission is present mainly in sectors CA4, CA3, and CA2. The amygdala sends important inputs to the hippocampus and is also believed to have a defective GABA system in schizophrenia. To explore the possibility that changes in the hippocampal GABAergic system could be related to an increased inflow of activity originating in the amygdala, a "partial" animal model has been developed. In awake, freely moving, rats a GABA(A) receptor antagonist was infused locally into the basolateral nuclear complex of the amygdala (BLn). Within 2 hours, a decreased density of both the 65- and 67-kDa isoforms of glutamate decarboxylase (GAD(65) and GAD(67)) -immunoreactive (IR) terminals was detected on neuron somata in sectors CA3 and CA2, but not in CA1, CA3, or dentate gyrus. An increase of GAD(67)-IR somata was also found in the dentate gyrus and CA4. In anterograde tracer studies, amygdalo-hippocampal projection fibers were exclusively found in CA3 and CA2, but not CA1. Taken together, these results indicate that activation of amygdalo-hippocampal afferents is associated with the induction of significant changes in the GABA system of the hippocampus, with a subregional distribution that is remarkably similar to that found in SZ. Under pathologic conditions, an excessive discharge of excitatory activity emanating from the amygdala could be capable of altering inhibitory modulation along the trisynaptic pathway. This mechanism may potentially contribute to disturbances of GABAergic function in the major psychoses. Such "partial" rodent modelling provides an important strategy for deciphering the effect of altered cortico-limbic circuits in SZ.
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Affiliation(s)
- S Berretta
- Laboratory for Structural Neuroscience, Mailman Research Center, McLean Hospital, 115 Mill Street, Belmont, MA 02478, USA
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24
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Lidow MS, Song ZM, Castner SA, Allen PB, Greengard P, Goldman-Rakic PS. Antipsychotic treatment induces alterations in dendrite- and spine-associated proteins in dopamine-rich areas of the primate cerebral cortex. Biol Psychiatry 2001; 49:1-12. [PMID: 11163774 DOI: 10.1016/s0006-3223(00)01058-1] [Citation(s) in RCA: 62] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
BACKGROUND Mounting evidence indicates that long-term treatment with antipsychotic medications can alter the morphology and connectivity of cellular processes in the cerebral cortex. The cytoskeleton plays an essential role in the maintenance of cellular morphology and is subject to regulation by intracellular pathways associated with neurotransmitter receptors targeted by antipsychotic drugs. METHODS We have examined whether chronic treatment with the antipsychotic drug haloperidol interferes with phosphorylation state and tissue levels of a major dendritic cytoskeleton-stabilizing agent, microtubule-associated protein 2 (MAP2), as well as levels of the dendritic spine-associated protein spinophilin and the synaptic vesicle-associated protein synaptophysin in various regions of the cerebral cortex of rhesus monkeys. RESULTS Among the cortical areas examined, the prefrontal, orbital, cingulate, motor, and entorhinal cortices displayed significant decreases in levels of spinophilin, and with the exception of the motor cortex, each of these regions also exhibited increases in the phosphorylation of MAP2. No changes were observed in either spinophilin levels or MAP2 phosphorylation in the primary visual cortex. Also, no statistically significant changes were found in tissue levels of MAP2 or synaptophysin in any of the cortical regions examined. CONCLUSIONS Our findings demonstrate that long-term haloperidol exposure alters neuronal cytoskeleton- and spine-associated proteins, particularly in dopamine-rich regions of the primate cerebral cortex, many of which have been implicated in the psychopathology of schizophrenia. The ability of haloperidol to regulate cytoskeletal proteins should be considered in evaluating the mechanisms of both its palliative actions and its side effects.
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Affiliation(s)
- M S Lidow
- University of Maryland, Department of Oral and Craniofacial Biological Sciences, Room 5-A-12, HHH, 666 W. Baltimore Street, Baltimore, MD 21201, USA
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25
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Dawson NM, Hamid EH, Egan MF, Meredith GE. Changes in the pattern of brain-derived neurotrophic factor immunoreactivity in the rat brain after acute and subchronic haloperidol treatment. Synapse 2001; 39:70-81. [PMID: 11071712 DOI: 10.1002/1098-2396(20010101)39:1<70::aid-syn10>3.0.co;2-j] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Our earlier work has shown that repeated administration of classical neuroleptic drugs gives rise to structural alterations in target regions of the mesolimbic pathway, most notably, nucleus accumbens. Such changes could be responsible for the efficacious or motor side effects associated with these drugs. Growth factors such as brain-derived neurotrophic factor (BDNF) provide trophic support for dopaminergic neurons during development and mediate synaptic and morphological plasticity in numerous regions of the adult CNS. The present study examines whether BDNF is altered in the mesolimbic pathway by classical neuroleptic treatment. Animals were administered haloperidol, 0.5 mg/kg, or vehicle, i.p., for either 3 or 21 days, followed by transcardiac perfusion with fixative. Three days of haloperidol administration dramatically decreased BDNF immunostaining in the neurons and fibers of the prefrontal cortex, hippocampus (dentate gyrus, CA2, and CA3), extended amygdala, and ventral tegmental area. BDNF-immunoreactive fibers virtually disappeared from the neostriatum and nucleus accumbens. Subchronic (21 days) treatment led to a rebound in BDNF immunoreactivity in most cell bodies but not in fibers. These results show that blockade of dopaminergic receptors with haloperidol rapidly downregulates BDNF in reward and emotional centers of the brain. Such rapid inactivation and subsequent reappearance of BDNF immunoreactivity could affect synaptic strength and plasticity and therefore be important preliminary steps in the cascade of neuronal events that lead to the efficacious or detrimental side effects of classical neuroleptic drugs.
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Affiliation(s)
- N M Dawson
- Department of Human Anatomy and Physiology, University College Dublin, National University of Ireland, Dublin, Ireland
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26
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Benes FM, Todtenkopf MS, Logiotatos P, Williams M. Glutamate decarboxylase(65)-immunoreactive terminals in cingulate and prefrontal cortices of schizophrenic and bipolar brain. J Chem Neuroanat 2000; 20:259-69. [PMID: 11207424 DOI: 10.1016/s0891-0618(00)00105-8] [Citation(s) in RCA: 94] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Recent postmortem studies have been suggesting that a defect of GABAergic neurotransmission might occur in the corticolimbic system of subjects with schizophrenia and bipolar disorder. To explore this possibility, a method for immunolocalizing the 65 kdalton isoform of glutamate decarboxylase (GAD(65)) has been developed and applied to the anterior cingulate (ACCx) and prefrontal (PFCx) cortices of 12 normal controls (CONs), 12 schizophrenics (SZs) and 5 manic depressive (MDs) subjects. A computer-assisted technique was employed under strictly blind conditions to determine the density of GAD(65)-IR terminals in apposition with pyramidal (PNs) and nonpyramidal (NPs) neurons and in neuropil (NPL) of layers II, III, V and VI of each cortical region. For SZs, no difference in the numerical density of GAD(65)-IR terminals in contact with either PNs or NPs or in NPL of layers II-VI in ACCx or PFCx was detected. There were also no differences in the size of either PNs and NPs that could have influenced the nature of these findings. Using a pixel count analysis, the size of IR terminals was, however, found to be increased in layers II (10.3%) and III (15.8%) of SZs, but only in subjects treated with neuroleptic drugs. For MDs, the density of GAD(65)-IR terminals was significantly reduced in all four layers of ACCx, but these differences were most significant in layers II (27.8%) and III (37.2%), whether or not the subjected were treated with neuroleptics. In PFCx, the MDs showed similar differences in terminal density for PNs and NPs but not neuropil in the four laminae examined. The MD group showed no differences in either the size of cell bodies or IR terminals. Age and PMI did not account for any of the differences between the CONs vs SZs and MDs. Overall, the results of this study, though preliminary, suggest that there may be complex changes in GABAergic terminals in SZ and MD, ones that may vary with respect to primary diagnosis and neuroleptic exposure.
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Affiliation(s)
- F M Benes
- Laboratory of Structural Neuroscience, McLean Hospital, 115 Mill Street, Belmont, MA 02178, USA.
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27
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Benes FM, Berretta S. Amygdalo-entorhinal inputs to the hippocampal formation in relation to schizophrenia. Ann N Y Acad Sci 2000; 911:293-304. [PMID: 10911881 DOI: 10.1111/j.1749-6632.2000.tb06733.x] [Citation(s) in RCA: 59] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
This chapter reviews recent postmortem studies of schizophrenic brain and discusses the potential role of the amygdala in the induction of hippocampal abnormalities in this disorder. Based on available evidence, sectors CA4, CA3, and CA2, but not CA1, show preferential changes in schizophrenic subjects, although the most pronounced changes have been found in CA3 and CA2. It seems likely that the amygdala would contribute in some way to the induction of abnormalities along the trisynaptic pathway via its direct input to sectors CA3 and CA2, as well as an indirect one that involves the entorhinal cortex and its perforant path projection to the area dentata. The postmortem findings reported to date have been integrated into a working model in which decreases of inhibitory GABAergic modulation are invoked to explain the observation from a recent PET scan study (Heckers et al., 1999) that baseline metabolic activity in the hippocampus of schizophrenics is increased. In addition, however, the apparent inability of schizophrenics to increase metabolic activity in the hippocampus when challenged with a memory retrieval task may reflect a disturbance of disinhibitory modulation postulated herein to occur in sector CA3, a key relay point along the trisynaptic pathway. Overall, it seems plausible that an increase of excitatory activity entering the hippocampus from the basolateral complex via both direct and indirect pathways may make a significant contribution to the pathophysiology of schizophrenia.
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Affiliation(s)
- F M Benes
- Laboratory for Structural Neuroscience, McLean Hospital, Belmont, Massachusetts, USA.
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28
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Chronwall BM, Hasan DS, Sands SA. Axonal plasticity in the rat pituitary intermediate lobe following chronic D2 receptor modulation. Ann N Y Acad Sci 2000; 897:415-9. [PMID: 10676467 DOI: 10.1111/j.1749-6632.1999.tb07910.x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- B M Chronwall
- School of Biological Sciences, University of Missouri-Kansas City 64110, USA.
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29
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Abstract
In addition to their neurochemical effects, antipsychotic (neuroleptic) drugs produce structural brain changes. This property is relevant not only for understanding the drugs' mode of action, but because it complicates morphological studies of schizophrenia. Here the histological neuropathological effects of antipsychotics are reviewed, together with brief mention of those produced by other treatments sometimes used in schizophrenia (electroconvulsive shock, lithium and antidepressants). Most data come from drug-treated rats, though there are also some human post-mortem studies with broadly congruent findings. The main alteration associated with antipsychotic medication concerns the ultrastructure and proportion of synaptic subpopulations in the caudate nucleus. In rats, synapses and dendrites in lamina VI of the prefrontal cortex are also affected. The changes are indicative of a drug-induced synaptic plasticity, although the underlying mechanisms are poorly understood. Similarly, it is unclear whether the neuropathological features relate primarily to the therapeutic action of antipsychotics or, more likely, to their predisposition to cause tardive dyskinesia and other motor side-effects. Clozapine seems to cause lesser and somewhat different alterations than do typical antipsychotics, albeit based on few data. There is no good evidence that antipsychotics cause neuronal loss or gliosis, nor that they promote neurofibrillary tangle formation or other features of Alzheimer's disease.
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Affiliation(s)
- P J Harrison
- University Department of Psychiatry, Warneford Hospital, Oxford, UK.
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30
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Ohnuma T, Augood SJ, Arai H, McKenna PJ, Emson PC. Measurement of GABAergic parameters in the prefrontal cortex in schizophrenia: focus on GABA content, GABA(A) receptor alpha-1 subunit messenger RNA and human GABA transporter-1 (HGAT-1) messenger RNA expression. Neuroscience 1999; 93:441-8. [PMID: 10465426 DOI: 10.1016/s0306-4522(99)00189-x] [Citation(s) in RCA: 120] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The hypothesis that the pathophysiology of schizophrenia may be associated with a dysfunction in GABA transmission in the human prefrontal cortex was investigated. Human post mortem brain tissue from 10 control cases and six cases of schizophrenia were processed for amino acid analysis and for radioactive in situ hybridization. Laminae III and V of three prefrontal cortical areas were examined in detail, namely Brodmann areas 9, 10 and 11. Of these three areas significant changes in GABAergic markers were found only in areas 9 and 10. Of note, a significant decrease in the tissue content of GABA was observed and this was accompanied by a marked increase in the cellular expression of the GABA(A) receptor alpha-1 subunit messenger RNA and a marked decrease in the expression of human GABA transporter-1, the messenger RNA encoding the neuronal GABA transporter protein. The amino acid analysis data provided in this study coupled with the detailed cellular study of several GABAergic markers in the human prefrontal cortex provide direct evidence in support of a disturbance in GABA transmission in the prefrontal cortex, which may be loosely termed "hypofrontality".
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Affiliation(s)
- T Ohnuma
- Department of Psychiatry, Juntendo University School of Medicine, Tokyo, Japan
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31
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Selemon LD, Lidow MS, Goldman-Rakic PS. Increased volume and glial density in primate prefrontal cortex associated with chronic antipsychotic drug exposure. Biol Psychiatry 1999; 46:161-72. [PMID: 10418690 DOI: 10.1016/s0006-3223(99)00113-4] [Citation(s) in RCA: 119] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
BACKGROUND Long term medication with antipsychotic drugs is known to produce changes in neurotransmitter levels and receptor sensitivity in the cortex; however, the anatomic consequences of chronic antipsychotic exposure are not well established. METHODS Accordingly, rhesus monkeys were given daily oral doses of typical or atypical antipsychotic drugs (TAP or AAP) or a placebo for 6 months. After treatment, a stereologic method was used to assess neuronal and glial density and cortical thickness in prefrontal area 46. RESULTS Neuronal density in drug-treated monkeys and controls did not differ in any cortical layer. Glial density was elevated in monkeys that received antipsychotic medications: as much as 33% in layers that receive dense excitatory afferents (layers I in TAP monkeys and IV in AAP monkeys). In addition, layer V was wider in all drug-treated monkeys. CONCLUSIONS Our findings indicate that glial proliferation and hypertrophy of the cerebral cortex is a common response to antipsychotic drugs. We hypothesize that these responses play a regulatory role in adjusting neurotransmitter levels or metabolic processes. Finally, the negative results with respect to neuronal density indicate that the elevated neuronal density found in the schizophrenic cortex is unlikely to be a medication effect.
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Affiliation(s)
- L D Selemon
- Section of Neurobiology, Yale University School of Medicine, New Haven, Connecticut 06510, USA
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Doherty MD, Gratton A. Effects of medial prefrontal cortical injections of GABA receptor agonists and antagonists on the local and nucleus accumbens dopamine responses to stress. Synapse 1999; 32:288-300. [PMID: 10332804 DOI: 10.1002/(sici)1098-2396(19990615)32:4<288::aid-syn5>3.0.co;2-u] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Stress stimulates dopamine (DA) release in nucleus accumbens (NAcc) but will do so more strongly in medial prefrontal cortex (PFC). Evidence indicates, however, that the cortical DA response to stress acts to dampen the concurrent increase in NAcc DA release. In the present study, we used voltammetry to investigate the role of PFC GABA in regulating the NAcc DA response to stress. The results of Experiment 1 show that the NAcc stress response is inhibited following bilateral cortical microinjections of baclofen (GABAB receptor agonist). While phaclofen (GABAB receptor antagonist) blocked the effect of baclofen, it had no significant effect of its own. Intra-PFC injections of muscimol (GABAA receptor agonist) and bicuculline (GABAA receptor antagonist) had no effect on the DA stress response in NAcc. In Experiment 2, we explored the possibility that GABA influences the NAcc DA stress response indirectly by modulating stress-induced DA release in PFC. None of the drugs tested had an effect on the PFC stress response at a dose (1 nmol) that produced reliable effects on the NAcc stress response. At an order of magnitude higher dose, however, locally applied phaclofen and muscimol enhanced and attenuated, respectively, the DA stress response in PFC. These results were validated in Experiment 3 by showing that intra-PFC injections of GBR-12395 (DA uptake blocker) and quinpirole (D2/D3 receptor agonist) dose-dependently enhanced and inhibited, respectively, the local DA stress response. Together, these findings indicate that increased GABA transmission in PFC exerts an inhibitory influence on the NAcc DA response to stress, and that this action is mediated primarily but not exclusively by GABAB receptors which may be located both on cortical output neurons and on DA terminals.
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Affiliation(s)
- M D Doherty
- Douglas Hospital Research Center, Department of Psychiatry, McGill University, Verdun, Québec, Canada
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The Anatomy of Dementias. Cereb Cortex 1999. [DOI: 10.1007/978-1-4615-4885-0_9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
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Storozhuk VM, Sanzharovsky AV, Busel BI. Interaction between dopamine and glutamate in the sensorimotor cortex during conditioned placing reaction. Neuroscience 1998; 85:347-59. [PMID: 9622235 DOI: 10.1016/s0306-4522(97)00643-x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Changes in impulse activity of sensorimotor cortex neurons associated with interaction of glutamate and dopamine during conditioned placing reaction were investigated in experiments on cats. Application of either glutamate or levodopa as a dopamine precursor increased background and evoked impulse activity in many of sensorimotor cortex neurons. It occurred occasionally that an increased impulse activity of cortical neurons produced by joint application of glutamate and levodopa could be much more intense than that produced by one of these substances. Amphetamine acted on cortical neurons in a similar way as levodopa. Haloperidol, a non-selective blocker of dopamine1 and dopamine2 receptors, increased or did not change background and evoked impulse activity in some cortical neurons. In contrast to application of glutamate alone, simultaneous application of glutamate and haloperidol to the neocortex depressed neuronal responses connected with conditioned movement. Thus, glutamate cannot exert its potentiating effect on evoked neuronal activity due to the depressing action of haloperidol. This means that glutamate potentiation is realized to a great extent through molecular mechanisms common for glutamate and dopamine, possibly through G-proteins which are common for glutamate metabotropic and dopamine receptors.
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Affiliation(s)
- V M Storozhuk
- Department of Brain Physiology, A. A. Bogomoletz Institute of Physiology, National Academy of Sciences of Ukraine, Kiev
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35
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Simpson MD, Slater P, Deakin JF, Gottfries CG, Karlsson I, Grenfeldt B, Crow TJ. Absence of basal ganglia amino acid neuron deficits in schizophrenia in three collections of brains. Schizophr Res 1998; 31:167-75. [PMID: 9689721 DOI: 10.1016/s0920-9964(98)00020-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Amino acid (glutamatergic, GABAergic) neuron deficiency theories of schizophrenia offer plausible explanations of pathogenesis. However, reports of disease-related reductions in amino acid synthesizing enzymes in post-mortem brains are contradictory. We measured neuronal uptake sites for gamma-aminobutyric acid (GABA; [3H]nipecotic acid binding) and nerve terminal/glial uptake sites for L-glutamate (D-[3H aspartate binding) in three independent groups of post-mortem brains from patients with schizophrenia and control subjects. Measurements were also made of the phencyclidine site of the glutamate N-methyl-D-aspartate (NMDA) receptor. Samples from patients showed no reductions in the binding of [3H]nipecotic acid or D-[3H]aspartate in caudate, putamen or globus pallidus. On the contrary, some increased binding of both ligands was observed in patients in many comparisons with controls. There were no clear-cut changes in NMDA receptor binding. The most consistent change in the brain sets was increased [3H]nipecotic acid binding in caudate-putamen. This could be due to neuroleptic treatment. The findings produce no evidence that schizophrenia involves major loss of GABA neuron terminals in the basal ganglia or losses of corticostriatal glutamatergic projections.
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Affiliation(s)
- M D Simpson
- School of Biological Sciences, Neuroscience Division, University of Manchester, UK
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Farnbach-Pralong D, Bradbury R, Copolov D, Dean B. Clozapine and olanzapine treatment decreases rat cortical and limbic GABA(A) receptors. Eur J Pharmacol 1998; 349:R7-8. [PMID: 9671088 DOI: 10.1016/s0014-2999(98)00285-4] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
The density of GABA(A) receptors in the hippocampus and the temporal cortex from rats treated for 28 days with either haloperidol, chlorpromazine, clozapine or olanzapine was measured. Compared to haloperidol (0.01 and 0.1 mg kg(-1) day(-1)) and chlorpromazine (0.1 and 1 mg kg(-1) day(-1)), clozapine and olanzapine (0.1 and 1 mg kg(-1) day(-1)) markedly decreased the density of GABA(A) receptors in these two brain regions. These data suggest that modulation of GABAergic transmission could be an important action of some antipsychotic drugs.
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Affiliation(s)
- D Farnbach-Pralong
- The Rebecca L. Cooper Research Laboratories, The Molecular Schizophrenia Division, The Mental Health Research Institute, Parkville, Victoria, Australia.
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Wu LC, D'Amelio F, Fox RA, Polyakov I, Daunton NG. Light microscopic image analysis system to quantify immunoreactive terminal area apposed to nerve cells. J Neurosci Methods 1997; 74:89-96. [PMID: 9210578 DOI: 10.1016/s0165-0270(97)02266-8] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The present report describes a desktop computer-based method for the quantitative assessment of the area occupied by immunoreactive terminals in close apposition to nerve cells in relation to the perimeter of the cell soma. This method is based on Fast Fourier Transform (FFT) routines incorporated in NIH-Image public domain software. Pyramidal cells of layer V of the somatosensory cortex outlined by GABA immunolabeled terminals were chosen for our analysis. A Leitz Diaplan light microscope was employed for the visualization of the sections. A Sierra Scientific Model 4030 CCD camera was used to capture the images into a Macintosh Centris 650 computer. After preprocessing, filtering was performed on the power spectrum in the frequency domain produced by the FFT operation. An inverse FFT with filter procedure was employed to restore the images to the spatial domain. Pasting of the original image to the transformed one using a Boolean logic operation called 'AND'ing produced an image with the terminals enhanced. This procedure allowed the creation of a binary image using a well-defined threshold of 128. Thus, the terminal area appears in black against a white background. This methodology provides an objective means of measurement of area by counting the total number of pixels occupied by immunoreactive terminals in light microscopic sections in which the difficulties of labeling intensity, size, shape and numerical density of terminals are avoided.
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Affiliation(s)
- L C Wu
- San José State University Foundation, CA 95192, USA
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Honer WG, Falkai P, Young C, Wang T, Xie J, Bonner J, Hu L, Boulianne GL, Luo Z, Trimble WS. Cingulate cortex synaptic terminal proteins and neural cell adhesion molecule in schizophrenia. Neuroscience 1997; 78:99-110. [PMID: 9135092 DOI: 10.1016/s0306-4522(96)00489-7] [Citation(s) in RCA: 111] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The neuronal organization and patterns of afferent innervation are abnormal in the cingulate cortex in schizophrenia, and associated changes in synaptic terminals could be present. A panel of monoclonal antibodies was defined with biochemical and fusion protein studies as detecting syntaxin (antibody SP6), synaptophysin (antibody SP4) and synaptosomal-associated protein-25 (antibody SP12). These antibodies and a polyclonal antibody reactive with neural cell adhesion molecule were used to investigate the cingulate cortex in schizophrenia. Immunocytochemistry indicated that syntaxin immunoreactivity had a considerably wider distribution than synaptophysin. Overall, multivariate analysis indicated increased synaptic terminal protein immunoreactivity in schizophrenia compared to controls (P=0.004). Controlled for age and post mortem interval, syntaxin immunoreactivity was significantly elevated in schizophrenia (P=0.004), and neural cell adhesion molecule immunoreactivity was also elevated (P=0.05). The neural cell adhesion molecule to synaptophysin ratio was increased (P=0.005), possibly indicating the presence of less mature synapses in schizophrenia. Elevated syntaxin immunoreactivity is consistent with increased glutamatergic afferents to the cingulate cortex in schizophrenia, and combined with the neural cell adhesion molecule to synaptophysin ratio results suggests that synaptic function in this region in schizophrenia may be abnormal.
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Affiliation(s)
- W G Honer
- Department of Psychiatry, University of British Columbia, Vancouver, Canada
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39
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Abstract
This chapter recounts efforts to dissect the cellular and circuit basis of a memory system in the primate cortex with the goal of extending the insights gained from the study of normal brain organization in animal models to an understanding of human cognition and related memory disorders. Primates and humans have developed an extraordinary capacity to process information "on line," a capacity that is widely considered to underlay comprehension, thinking, and so-called executive functions. Understanding the interactions between the major cellular constituents of cortical circuits-pyramidal and nonpyramidal cells-is considered a necessary step in unraveling the cellular mechanisms subserving working memory mechanisms and, ultimately, cognitive processes. Evidence from a variety of sources is accumulating to indicate that dopamine has a major role in regulating the excitability of the cortical circuitry upon which the working memory function of prefrontal cortex depends. Here, I describe several direct and indirect intercellular mechanisms for modulating working memory function in prefrontal cortex based on the localization of dopamine receptors on the distal dendrites and spines of pyramidal cells and on interneurons in the prefrontal cortex. Interactions between monoamines and a compromised cortical circuitry may hold the key to understanding the variety of memory disorders associated with aging and disease.
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Affiliation(s)
- P S Goldman-Rakic
- Section of Neurobiology, Yale University School of Medicine, New Haven, CT 06510, USA
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Mijnster MJ, Ingham CA, Meredith GE, Docter GJ, Arbuthnott GW. Morphological changes in met(5)-enkephalin-immunoreactive synaptic boutons in the rat neostriatum after haloperidol decanoate treatment. Eur J Neurosci 1996; 8:716-26. [PMID: 9081623 DOI: 10.1111/j.1460-9568.1996.tb01257.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The morphological plasticity of an identified population of synaptic boutons in the rat neostriatum was investigated 24 h (short-term treatment) or 14 days (long-term treatment) after administration of the depot neuroleptic, haloperidol decanoate. Specific methionine(5)-enkephalin antiserum was used to label bouton profiles in the dorsal neostriatum. The size and shape of these boutons was subsequently analysed with quantitative methods at the ultrastructural level. Immunoreactive synaptic bouton profiles were found to have a larger cross-sectional area, to be less circular in shape and to have a longer maximum diameter after long-term neuroleptic treatment. These parameters were not significantly affected by short-term neuroleptic treatment. The morphological parameters indicate that methionine(5)-enkephalin-immunoreactive boutons become enlarged, probably by elongating. This suggests that boutons containing methionine(5)-enkephalin increase their potential synaptic efficacy in the long term after neuroleptic treatment.
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Affiliation(s)
- M J Mijnster
- Research Institute of Neuroscience, Vrije Universiteit, Department of Anatomy and Embryology, Amsterdam, The Netherlands
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Dawirs RR, Teuchert-Noodt G, Czaniera R. Ontogeny of PFC-related behaviours is sensitive to a single non-invasive dose of methamphetamine in neonatal gerbils (Meriones unguiculatus). J Neural Transm (Vienna) 1996; 103:1235-45. [PMID: 9013410 DOI: 10.1007/bf01271184] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
A single dose of methamphetamine (50 mg/kg; i.p.) was administered to neonatal male gerbils (Meriones unguiculatus) aged 14 days, and adult prefrontal cortex (PFC)-related behaviours were analysed and compared with saline-treated controls at the age of postnatal day 90. For that purpose, animals were tested for open-field activities and y-maze delayed alternation. This solitary and non-invasive drug challenge, which has recently been found to initiate serious restraint in maturation of the mesoprefrontal dopamine (DA)-system (Dawirs et al., 1994), induces a significant delayed alternation impairment as well as significant increases in open-field motor activity and emotionality. Since an undisturbed development of the prefrontal DA-innervation seems to be a precondition for the maturation of normal PFC-related behaviours, a single early methamphetamine impact may be a suitable animal model for further investigation of structural and functional aspects of non-invasively induced behavioural deficits in rodents. The present results are discussed with regard to the assumption that hypofunctional mesoprefrontal DA-systems might be basic to schizophrenic behaviours in man.
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Affiliation(s)
- R R Dawirs
- Department of Neuroanatomy, Faculty of Biology, University of Bielefeld, Federal Republic of Germany
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42
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Roberts RC, Gaither LA, Gao XM, Kashyap SM, Tamminga CA. Ultrastructural correlates of haloperidol-induced oral dyskinesias in rat striatum. Synapse 1995; 20:234-43. [PMID: 7570355 DOI: 10.1002/syn.890200307] [Citation(s) in RCA: 66] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Neuroleptics given chronically to rats induce behavioral sequelae which mimic tardive dyskinesia in some respects. The intent of this study was to investigate the ultrastructural correlates of oral dyskinesias (vacuous chewing movements [VCMs]), induced by chronic haloperidol treatment. After 6 months of treatment, rats were divided into low or high VCM groups. Rats in the high VCM group were either sacrificed on drug or were withdrawn from drug for 4 weeks. Ultrastructural analyses of the striatum indicated that synaptic density: 1) was significantly decreased in both the low and high VCM groups compared to normal controls; 2) was more profoundly decreased in the high VCM group as compared to the low VCM group; and 3) recovered to normal following drug withdrawal. Compared to controls, the density of asymmetric synapses was reduced by a similar magnitude in both the low and high VCM groups, suggesting that this change is a result of haloperidol treatment and independent of VCMs. Conversely, the density of symmetric synapses was reduced compared to normal, only in the high VCM group, suggesting that this change is specifically related to the expression of VCMs. In addition, mitochondrial profiles were hypertrophied and less frequent in the high VCM group in comparison to controls; size, but not number, recovered following drug withdrawal. These results identify distinct ultrastructural correlates of chronic haloperidol treatment that are unique to rats that develop VCMs and suggest that these ultrastructural features may play a role in the pathophysiology of oral dyskinesias in rats.
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Affiliation(s)
- R C Roberts
- Maryland Psychiatric Research Center, Department of Psychiatry, University of Maryland School of Medicine, Baltimore 21228, USA
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