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Phosphodiesterases PDE2A and PDE10A both change mRNA expression in the human brain with age, but only PDE2A changes in a region-specific manner with psychiatric disease. Cell Signal 2020; 70:109592. [PMID: 32119913 DOI: 10.1016/j.cellsig.2020.109592] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2020] [Revised: 02/26/2020] [Accepted: 02/27/2020] [Indexed: 12/11/2022]
Abstract
Many studies implicate altered cyclic nucleotide signaling in the pathophysiology of major depressive disorder (MDD), bipolar disorder (BPD), and schizophrenia (SCZ). As such, we explored how phosphodiesterases 2A (PDE2A) and 10A (PDE10A)-enzymes that break down cyclic nucleotides-may be altered in brains of these patients. Using autoradiographic in situ hybridization on postmortem brain tissue from the Stanley Foundation Neuropathology Consortium, we measured expression of PDE2 and PDE10 mRNA in multiple brain regions implicated in psychiatric pathophysiology, including cingulate cortex, orbital frontal cortex (OFC), superior temporal gyrus, hippocampus, parahippocampal cortex, amygdala, and the striatum. We also assessed how PDE2A and PDE10A expression changes in these brain regions across development using the Allen Institute for Brain Science Brainspan database. Compared to controls, patients with SCZ, MDD and BPD all showed reduced PDE2A mRNA in the amygdala. In contrast, PDE2A expression changes in frontal cortical regions were only significant in patients with SCZ, while those in caudal entorhinal cortex, hippocampus, and the striatum were most pronounced in patients with BPD. PDE10A expression was only detected in striatum and did not differ by disease group; however, all groups showed significantly less PDE10A mRNA expression in ventral versus dorsal striatum. Across development, PDE2A mRNA increased in these brain regions; whereas, PDE10A mRNA expression decreased in all regions except striatum. Thus, PDE2A mRNA expression changes in both a disorder- and brain region-specific manner, potentially implicating PDE2A as a novel diagnostic and/or patient-selection biomarker or therapeutic target.
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Bergman O, Ben-Shachar D. Mitochondrial Oxidative Phosphorylation System (OXPHOS) Deficits in Schizophrenia: Possible Interactions with Cellular Processes. CANADIAN JOURNAL OF PSYCHIATRY. REVUE CANADIENNE DE PSYCHIATRIE 2016; 61:457-69. [PMID: 27412728 PMCID: PMC4959648 DOI: 10.1177/0706743716648290] [Citation(s) in RCA: 110] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Mitochondria are key players in the generation and regulation of cellular bioenergetics, producing the majority of adenosine triphosphate molecules by the oxidative phosphorylation system (OXPHOS). Linked to numerous signaling pathways and cellular functions, mitochondria, and OXPHOS in particular, are involved in neuronal development, connectivity, plasticity, and differentiation. Impairments in a variety of mitochondrial functions have been described in different general and psychiatric disorders, including schizophrenia (SCZ), a severe, chronic, debilitating illness that heavily affects the lives of patients and their families. This article reviews findings emphasizing the role of OXPHOS in the pathophysiology of SCZ. Evidence accumulated during the past few decades from imaging, transcriptomic, proteomic, and metabolomic studies points at OXPHOS deficit involvement in SCZ. Abnormalities have been reported in high-energy phosphates generated by the OXPHOS, in the activity of its complexes and gene expression, primarily of complex I (CoI). In addition, cellular signaling such as cAMP/protein kinase A (PKA) and Ca(+2), neuronal development, connectivity, and plasticity have been linked to OXPHOS function and are reported to be impaired in SCZ. Finally, CoI has been shown as a site of interaction for both dopamine (DA) and antipsychotic drugs, further substantiating its role in the pathology of SCZ. Understanding the role of mitochondria and the OXPHOS in particular may encourage new insights into the pathophysiology and etiology of this debilitating disorder.
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Affiliation(s)
- Oded Bergman
- Laboratory of Psychobiology, Department of Psychiatry, Rambam Medical Center, Technion-IIT, Haifa, Israel B. Rappaport Faculty of Medicine, Technion-IIT, Haifa, Israel
| | - Dorit Ben-Shachar
- Laboratory of Psychobiology, Department of Psychiatry, Rambam Medical Center, Technion-IIT, Haifa, Israel B. Rappaport Faculty of Medicine, Technion-IIT, Haifa, Israel
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A combined metabonomic and proteomic approach identifies frontal cortex changes in a chronic phencyclidine rat model in relation to human schizophrenia brain pathology. Neuropsychopharmacology 2013; 38:2532-44. [PMID: 23942359 PMCID: PMC3799075 DOI: 10.1038/npp.2013.160] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/06/2013] [Revised: 06/03/2013] [Accepted: 06/14/2013] [Indexed: 01/30/2023]
Abstract
Current schizophrenia (SCZ) treatments fail to treat the broad range of manifestations associated with this devastating disorder. Thus, new translational models that reproduce the core pathological features are urgently needed to facilitate novel drug discovery efforts. Here, we report findings from the first comprehensive label-free liquid-mass spectrometry proteomic- and proton nuclear magnetic resonance-based metabonomic profiling of the rat frontal cortex after chronic phencyclidine (PCP) intervention, which induces SCZ-like symptoms. The findings were compared with results from a proteomic profiling of post-mortem prefrontal cortex from SCZ patients and with relevant findings in the literature. Through this approach, we identified proteomic alterations in glutamate-mediated Ca(2+) signaling (Ca(2+)/calmodulin-dependent protein kinase II, PPP3CA, and VISL1), mitochondrial function (GOT2 and PKLR), and cytoskeletal remodeling (ARP3). Metabonomic profiling revealed changes in the levels of glutamate, glutamine, glycine, pyruvate, and the Ca(2+) regulator taurine. Effects on similar pathways were also identified in the prefrontal cortex tissue from human SCZ subjects. The discovery of similar but not identical proteomic and metabonomic alterations in the chronic PCP rat model and human brain indicates that this model recapitulates only some of the molecular alterations of the disease. This knowledge may be helpful in understanding mechanisms underlying psychosis, which, in turn, can facilitate improved therapy and drug discovery for SCZ and other psychiatric diseases. Most importantly, these molecular findings suggest that the combined use of multiple models may be required for more effective translation to studies of human SCZ.
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Guest PC, Urday S, Ma D, Stelzhammer V, Harris LW, Amess B, Pietsch S, Oheim C, Ozanne SE, Bahn S. Proteomic analysis of the maternal protein restriction rat model for schizophrenia: identification of translational changes in hormonal signaling pathways and glutamate neurotransmission. Proteomics 2012; 12:3580-9. [PMID: 23071080 DOI: 10.1002/pmic.201200376] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2012] [Revised: 10/01/2012] [Accepted: 10/01/2012] [Indexed: 11/07/2022]
Abstract
Previous studies have found that some first onset schizophrenia patients show signs of impaired insulin signaling. Also, epidemiological studies have shown that periods of suboptimal nutrition including protein deficiencies during pregnancy can lead to increased incidence of metabolic conditions and psychiatric disorders in the offspring. For these reasons, we have carried out a molecular profiling analysis of blood serum and brain tissues from adult offspring produced by the maternal low protein (LP) rat model. The results showed similar changes to those seen in schizophrenia. Multiplex immunoassay profiling identified changes in the levels of insulin, adiponectin, and leptin along with alterations in inflammatory and vascular system-related proteins such as osteopontin, macrophage colony-stimulating factor 1, and vascular cell adhesion molecule 1. LC-MS(E) proteomic profiling showed that glutamatergic pathways were altered in frontal cortex, while signaling pathways and cytoskeletal proteins involved in hormonal secretion and synaptic remodeling were altered in the hypothalamus. Taken together, these studies indicate that the LP rat model recapitulates several pathophysiological attributes seen in schizophrenia patients. We propose that the LP model may have utility for drug discovery efforts, especially to identify compounds that modulate the metabolic and glutamatergic systems.
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Affiliation(s)
- Paul C Guest
- Department of Chemical Engineering and Biotechnology, University of Cambridge, Cambridge, UK.
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5
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Abstract
Schizophrenia is one of the most common psychiatric disorders, but despite some progress in identifying the genetic factors implicated in its development, the molecular mechanisms underlying its etiology and pathogenesis remain poorly understood. However, accumulating evidence suggests that regardless of the underlying genetic complexity, the mechanisms of the disease may impact a small number of common signaling pathways. In this review, we discuss the evidence for a role of schizophrenia susceptibility genes in intracellular signaling cascades by focusing on three prominent candidate genes: AKT, PPP3CC (calcineurin), and DISC1. We describe the regulation of a number of signaling cascades by AKT and calcineurin through protein phosphorylation and dephosphorylation, and the recently uncovered functions of DISC1 in cAMP and GSK3beta signaling. In addition, we present independent evidence for the involvement of their downstream signaling pathways in schizophrenia. Finally, we discuss evidence supporting an impact of these susceptibility genes on common intracellular signaling pathways and the convergence of their effects on neuronal processes implicated in schizophrenia.
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Affiliation(s)
- Mirna Kvajo
- Department of Physiology and Cellular Biophysics, College of Physicians and Surgeons, Columbia University, New York, NY 10032, USA.
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6
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Matsuzaki S, Tohyama M. Regulation of pituitary adenylyl cyclase-activating polypeptide (PACAP, ADCYAP1: adenylyl cyclase-activating polypeptide 1) in the treatment of schizophrenia. Expert Opin Ther Targets 2008; 12:1097-108. [PMID: 18694377 DOI: 10.1517/14728222.12.9.1097] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
BACKGROUND Deficiency of pituitary adenylyl cyclase-activating polypeptide (PACAP) and its specific receptor, PAC1, causes a schizophrenia-like phenotype in mice. In addition, the relation of the PACAP and PAC1 genes to schizophrenia has been shown by single-nucleotide polymorphism association studies. Furthermore, PACAP is reported to be involved in the function of disrupted-in-schizophrenia 1. OBJECTIVE To summarize briefly the recent evidence relating the PACAP system and schizophrenia and discuss the application of PACAP to the treatment of schizophrenia. RESULTS/CONCLUSION The regulation of PACAPergic signals is an interesting potential treatment for schizophrenia. Further studies of PACAP signals and the association of PACAP signals with schizophrenia should shed the light on the utility of this approach in the treatment of schizophrenia.
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Affiliation(s)
- Shinsuke Matsuzaki
- Osaka University, The Osaka-Hamamatsu Joint Research Center for Child Mental Development, Graduate School of Medicine, Department of Anatomy and Neuroscience, 2-2 Yamadaoka, Suita, Osaka 565-0871, Japan.
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7
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Arranz B, Rosel P, San L, Ramírez N, Dueñas RM, Salavert J, Centeno M, del Moral E. Low baseline serotonin-2A receptors predict clinical response to olanzapine in first-episode schizophrenia patients. Psychiatry Res 2007; 153:103-9. [PMID: 17629952 DOI: 10.1016/j.psychres.2006.12.015] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/09/2006] [Revised: 10/31/2006] [Accepted: 12/16/2006] [Indexed: 10/23/2022]
Abstract
The purpose of this study was to determine whether platelet serotonin-2A (5-HT2A) binding sites and inositol 1,4,5 trisphosphate (IP3) concentrations before treatment can identify olanzapine-responsive patients. The study included 21 never medicated, first-episode schizophrenia patients (antipsychotic-naïve) and 21 patients with a DSM-IV-TR diagnosis of paranoid schizophrenia who had not received depot antipsychotic treatment in the previous 6 months or oral antipsychotic or antidepressant treatment in the previous 2 months (antipsychotic-free). In the antipsychotic-naïve group, olanzapine responders had a significantly lower number of 5-HT2A receptors and lower IP3 concentrations at baseline than non-responders. The combination of baseline 5-HT2A and IP3 values significantly predicted an improvement in negative symptomatology after 6 weeks of treatment with olanzapine. In the antipsychotic-free group, responders had significantly higher positive and lower negative symptomatology at baseline, together with a reduced number of 5-HT2A receptors. However, basal 5-HT2A receptors or IP3 concentrations did not significantly predict positive, negative or general clinical response. The reported results suggest that platelet 5-HT2A binding might be a trait marker that could help to identify those patients likely to show greater improvement in negative symptomatology after olanzapine treatment.
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Affiliation(s)
- Belén Arranz
- Department of Psychiatry, Hospital San Rafael, and Department of Clinical Chemistry, Ciutat Sanitaria i Universitaria de Bellvitge, Barcelona, Spain
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8
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Gurguis GN. Psychiatric Disorders. Platelets 2007. [DOI: 10.1016/b978-012369367-9/50806-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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Gould TJ, Bizily SP, Tokarczyk J, Kelly MP, Siegel SJ, Kanes SJ, Abel T. Sensorimotor gating deficits in transgenic mice expressing a constitutively active form of Gs alpha. Neuropsychopharmacology 2004; 29:494-501. [PMID: 14694347 PMCID: PMC3348581 DOI: 10.1038/sj.npp.1300309] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Schizophrenia is a complex disorder characterized by wide-ranging cognitive impairments, including deficits in learning as well as sensory gating. The causes of schizophrenia are unknown, but alterations in intracellular G-protein signaling pathways are among the molecular changes documented in patients with schizophrenia. Using the CaMKIIalpha promoter to drive expression in neurons within the forebrain, we have developed transgenic mice that express a constitutively active form of G(s)alpha (G(s)alpha(*)), the G protein that couples receptors such as the D(1) and D(5) dopamine receptors to adenylyl cyclase. We have also generated mice in which the CaMKIIalpha promoter drives expression of a dominant-negative form of protein kinase A, R(AB). Here, we examine startle responses and prepulse inhibition of the startle reflex (PPI) in these G(s)alpha(*) and R(AB) transgenic mice. G(s)alpha(*) transgenic mice exhibited selective deficits in PPI, without exhibiting alterations in the startle response, whereas no deficit in startle or PPI was found in the R(AB) transgenic mice. Thus, overstimulation of the cAMP/PKA pathway disrupts PPI, but the cAMP/PKA pathway may not be essential for sensorimotor gating. G(s)alpha(*) transgenic mice may provide an animal model of certain endophenotypes of schizophrenia, because of the similarities between them and patients with schizophrenia in G-protein function, hippocampus-dependent learning, and sensorimotor gating.
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Affiliation(s)
- Thomas J Gould
- Department of Psychology, Temple University, Weiss Hall, Philadelphia, PA, USA
| | - Scott P Bizily
- Department of Biology, University of Pennsylvania, Philadelphia, PA, USA
- Division of Neuropsychiatry, University of Pennsylvania, Philadelphia, PA, USA
| | - Jan Tokarczyk
- Division of Neuropsychiatry, University of Pennsylvania, Philadelphia, PA, USA
| | - Michele P Kelly
- Department of Biology, University of Pennsylvania, Philadelphia, PA, USA
- Division of Neuropsychiatry, University of Pennsylvania, Philadelphia, PA, USA
| | - Steven J Siegel
- Division of Neuropsychiatry, University of Pennsylvania, Philadelphia, PA, USA
| | - Stephen J Kanes
- Division of Neuropsychiatry, University of Pennsylvania, Philadelphia, PA, USA
| | - Ted Abel
- Department of Biology, University of Pennsylvania, Philadelphia, PA, USA
- Correspondence: Dr T Abel, Department of Biology, University of Pennsylvania, 319 Leidy Labs, 38th and Hamilton Walk, Philadelphia, PA 19104, USA, Tel: +1 215 898 5614, Fax: +1 215 898 8780,
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10
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Todorova VK, Elbein AD, Kyosseva SV. Increased expression of c-Jun transcription factor in cerebellar vermis of patients with schizophrenia. Neuropsychopharmacology 2003; 28:1506-14. [PMID: 12799614 DOI: 10.1038/sj.npp.1300211] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
In the cerebellar vermis of schizophrenic patients, our previous studies have revealed alterations in the mitogen-activated protein (MAP) kinase signaling cascade and downstream transcription factors within the c-fos promoter. Since the proteins of the Fos and Jun families of immediate-early genes dimerize to form activating protein (AP)-1, the present study was conducted to examine the expression of Jun transcription factors in schizophrenic and control subjects. Using Western blot analysis, we determined the protein levels of c-Jun, Jun B, and Jun D as well as the levels of c-jun mRNA by relative RT-PCR in post-mortem samples from cerebellar vermis. The expression of c-Jun protein and c-jun mRNA was significantly increased in the cerebellar vermis of patients with schizophrenia, whereas no significant differences were found in the expression of Jun B or Jun D proteins. Studies in rats indicated that the abnormal expression of c-Jun transcription factor observed in schizophrenic patients was not related to post-mortem intervals or chronic treatment with antipsychotic medications. This study provides new insights into cerebellar abnormalities of schizophrenia at the level of expression of c-Jun that target key genes associated with the MAP kinase cascade.
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Affiliation(s)
- Valentina K Todorova
- Department of Biochemistry and Molecular Biology, University of Arkansas for Medical Sciences, 4301 West Markham Street, Little Rock, AR 72205, USA
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11
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Abstract
Ontogenetic brain-asymmetry and its reversal in schizophrenia constitute special cases of a more fundamental principle of sensory-motor integration. Transmitted through an immature optical system, asymmetric inputs from the left visual field induce the infant's right hemispheric preference for lower spatial frequencies during early mother-child interaction. The emerging classical features of hemispheric specialisation later in life can be accounted for by a transformation law of the neuronal reference frames based on relativistic non-linear information processing. Accordingly, the asymmetric distributions of the cannabinoid receptor CB1 in the right basal ganglia and the left area of Wernicke reflect the preferences for lateralised posture, positioning, and speech. Epigenetic development of brain asymmetry thus unifies the different aspects related to cradling and breast-feeding, speech- and visuospatial processing, the dimensional conversion of spatiotemporal information and, in the case of a dysbalanced cannabinoid system, its psychotic reversal. The predicted right hemispheric shift and the inverse relationship between Kolmogorov entropy and its dimensional embedding (Shannon entropy) has ultimately been confirmed by non-linear EEG analysis of a fluoro-methyl-anadamide induced model psychosis splitting conscious from unconscious mental processes.
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Affiliation(s)
- M Fritzsche
- Praxis für Innere Medizin, Adliswil, Switzerland.
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12
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Pongrac J, Middleton FA, Lewis DA, Levitt P, Mirnics K. Gene expression profiling with DNA microarrays: advancing our understanding of psychiatric disorders. Neurochem Res 2002; 27:1049-63. [PMID: 12462404 DOI: 10.1023/a:1020904821237] [Citation(s) in RCA: 92] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
DNA microarray transcriptome profiling of the postmortem brain opens novel horizons in understanding molecular changes associated with complex psychiatric disorders. With careful analysis and interpretation of microarray data we are uncovering previously unknown, expression patterns that maybe subject-specific and pivotal in understanding the disease process. In our recent studies, analyses of the prefrontal cortex of subjects with schizophrenia and matched controls uncovered complex changes in the expression of genes related to presynaptic secretory release, GABAergic and glutamatergic transmission, metabolic pathways, myelination, as well as cAMP and phosphoinositol second messenger systems. Our goal will be to integrate this expression data within the context of the relevant anatomical, biochemical, molecular, imaging and clinical findings.
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13
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Avissar S, Roitman G, Schreiber G. Differential effects of the antipsychotics haloperidol and clozapine on G protein measures in mononuclear leukocytes of patients with schizophrenia. Cell Mol Neurobiol 2001; 21:799-811. [PMID: 12043849 DOI: 10.1023/a:1015164423918] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
AIMS Heterotrimeric G proteins play a pivotal role in postreceptor information transduction. These proteins were previously implicated in the pathophysiology and treatment of mood and other neuropsychiatric disorders. Recently we showed that untreated patients with schizophrenia have a significantly elevated dopamine-induced Gs protein function which is correlated with the severity of the psychotic symptoms. In contrast, an inverse picture with reduction in the function and the immunoreactivity of Gs protein was detected in patients with Parkinson's disease. The present study aims at investigating the effect of antipsychotic medications on dopamine-induced Gs protein hyperfunction in schizophrenia comparing the classical antipsychotic haloperidol and the newer antipsychotic clozapine, which is devoid of extrapyramidal side effects, on G protein measures. METHODS G protein functional measurements coupled to beta-adrenergic, muscarinic, and dopamine receptors were undertaken through bacterial toxin sensitive, agonist enhanced [3H]-Gpp(NH)p binding capacity, substantiated by quantitative measures of Gs alpha, Gi alpha, and G beta subunit proteins through immunoblot analysis in mononuclear leukocytes obtained from patients with schizophrenia under haloperidol, or clozapine treatments in comparison with untreated patients with schizophrenia and healthy volunteers. RESULTS Dopamine-induced Gs hyperfunction characteristic of untreated patients with schizophrenia was not detected under antipsychotic treatment with either haloperidol or clozapine. Haloperidol caused a significant decrease in Gs function and immunoreactivity below normal levels. The extend of reduction in Gs function was found to be correlated with the intensity of extrapyramidal side effects. The pattern of G protein subunits levels in patients with schizophrenia under haloperidol treatment resembles the one obtained in patients with Parkinson's disease. CONCLUSIONS In the present study it is shown that G protein measurements in patients with schizophrenia under antipsychotic treatments can be used to biochemically monitor effects of antipsychotic medications in living patients. Moreover, these measurements may be used also for monitoring parkinsonian side effects induced by antipsychotic medications.
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MESH Headings
- Adult
- Antipsychotic Agents/pharmacology
- Binding, Competitive/drug effects
- Binding, Competitive/physiology
- Brain Chemistry/drug effects
- Brain Chemistry/physiology
- Clozapine/pharmacology
- Dopamine/metabolism
- Dopamine Agonists/pharmacology
- Female
- GTP-Binding Proteins/drug effects
- GTP-Binding Proteins/metabolism
- Haloperidol/pharmacology
- Humans
- Leukocytes, Mononuclear/drug effects
- Leukocytes, Mononuclear/metabolism
- Male
- Middle Aged
- Parkinson Disease/metabolism
- Parkinson Disease/physiopathology
- Receptors, Adrenergic, beta/drug effects
- Receptors, Adrenergic, beta/metabolism
- Receptors, Dopamine/drug effects
- Receptors, Dopamine/metabolism
- Receptors, Muscarinic/drug effects
- Receptors, Muscarinic/metabolism
- Schizophrenia/drug therapy
- Schizophrenia/metabolism
- Schizophrenia/physiopathology
- Up-Regulation/drug effects
- Up-Regulation/physiology
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Affiliation(s)
- S Avissar
- Department of Clinical Pharmacology, Ben Gurion University of the Negev, Beer Sheva, Israel.
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14
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Monroy X, Romero G, Pérez MP, Farré AJ, Guitart X. Decrease of adenylyl cyclase activity and expression by a sigma1 receptor ligand and putative atypical antipsychotic. Neuroreport 2001; 12:1989-92. [PMID: 11435935 DOI: 10.1097/00001756-200107030-00042] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
We examined whether changes in the adenylyl cyclase system could be induced by the administration of the sigma1 receptor ligand and putative atypical antipsychotic 4-[4-fluorophenyl]-1,2,3,6-tetrahydro-1-[4-[1,-2,4-triazol-1-il]butyl]pyridine citrate) (E-5842). Repeated (21 days) but not acute (2 h) treatment with E-5842 induced a significant decrease in adenylyl cyclase type I immunoreactivity and adenylyl cyclase activity in rat frontal cortex membranes, with less or no effect in other brain regions such as the hippocampus or the striatum. Changes in immunoreactivity were not observed in other adenylyl cyclases (type V/VI). The reported changes, observed only after a chronic treatment, could be related to the mechanism of action of sigma receptor ligands in general or to that of E-5842 in particular and should be taken into account, given the long duration of treatment in psychiatric patients.
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Affiliation(s)
- X Monroy
- Department of Neuropharmacology, Research Center, Laboratoris Esteve, S.A., Verge de Montserrat 221, 08041-Barcelona, Spain
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15
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Perera T, Lisanby SH, Sackheim HA. Protein kinase a in major depression: the link between hypothalamic-pituitary-adrenal axis hyperactivity and neurogenesis. CNS Spectr 2001; 6:565-8, 571-2. [PMID: 15573020 DOI: 10.1017/s1092852900002108] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
The latest and most generative biological theories of major depression center on two major hypotheses. The first focuses on the concept that hyperactivity of the hypothalamic-pituitary-adrenal (HPA) axis leads to many of the pathological changes in the brain that accompany major depression. The second posits that neurogenesis leads to the repair of depression-related injuries. These two hypotheses are complementary: the former alludes to the etiology or consequences of depression, while the latter suggests mechanisms of antidepressant action. Significant crosstalk occurs between these two systems at many levels. Protein kinase A (PKA) may play an important role in this crosstalk at the intracellular level of signaling cascades. PKA is involved in the formation of long-term potentiation and fear conditioning in response to stress. Chronic stress leads to the suppression of hippocampal activity, which may cause the hyperactivity of the HPA axis during melancholic depression. PKA is also involved in the stimulation of hippocampal neurogenesis after antidepressant treatment. In theory, neurogenesis may lead to the restoration of hippocampal function, and this may be the mechanism that leads to antidepressant-mediated normalization of HPA hyperactivity. Thus, PKA is active during processes that potentially lead to depression and other processes that lead to the resolution of the illness. These opposing processes may be mediated by separate PKA isozymes that activate two distinct pathways. This review highlights the dual role of this enzyme in two biological hypotheses pertaining to depression and its treatment.
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Affiliation(s)
- T Perera
- Department of Psychiatry, Columbia University, New York, NY, USA.
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16
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Mirnics K, Middleton FA, Stanwood GD, Lewis DA, Levitt P. Disease-specific changes in regulator of G-protein signaling 4 (RGS4) expression in schizophrenia. Mol Psychiatry 2001; 6:293-301. [PMID: 11326297 DOI: 10.1038/sj.mp.4000866] [Citation(s) in RCA: 320] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/21/2000] [Revised: 12/12/2000] [Accepted: 12/14/2000] [Indexed: 11/09/2022]
Abstract
Complex defects in neuronal signaling may underlie the dysfunctions that characterize schizophrenia. Using cDNA microarrays, we discovered that the transcript encoding regulator of G-protein signaling 4 (RGS4) was the most consistently and significantly decreased in the prefrontal cortex of all schizophrenic subjects examined. The expression levels of ten other RGS family members represented on the microarrays were unchanged and hierarchical data analysis revealed that as a group, 274 genes associated with G-protein signaling were unchanged. Quantitative in situ hybridization verified the microarray RGS4 data, and demonstrated highly correlated decreases in RGS4 expression across three cortical areas of ten subjects with schizophrenia. RGS4 expression was not altered in the prefrontal cortex of subjects with major depressive disorder or in monkeys treated chronically with haloperidol. Interestingly, targets for 70 genes mapped to the major schizophrenia susceptibility locus 1q21--22 were present on the microarrays, of which only RGS4 gene expression was consistently altered. The combined data indicate that a decrease in RGS4 expression may be a common and specific feature of schizophrenia, which could be due either to genetic factors or a disease- specific adaptation, both of which could affect neuronal signaling.
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Affiliation(s)
- K Mirnics
- Department of Neurobiology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, USA. karoly+@pitt.edu
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17
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Shirakawa O, Kitamura N, Lin XH, Hashimoto T, Maeda K. Abnormal neurochemical asymmetry in the temporal lobe of schizophrenia. Prog Neuropsychopharmacol Biol Psychiatry 2001; 25:867-77. [PMID: 11383982 DOI: 10.1016/s0278-5846(01)00149-x] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Neuroanatomical asymmetries are known to be present in the human brain, and loss of reversal of these asymmetries, particularly through changes in the left temporal lobe, have been found in the brains of patients with schizophrenia. In addition to disturbed neuroanatomical asymmetries, disturbed neurochemical asymmetries have also been reported in the brains of patients with schizophrenia. However, in the temporal lobe, the laterality of most of these neurochemical changes has not been specifically evaluated. Few neurochemical studies have addressed left-right differences in the superior temporal gyrus (STG). A deteriorated serotonin2A receptor-G protein qalpha (Gqalpha)-phosphoinositide-specific phospholipase C beta1(PLC beta1) cascade has been found in the left, but not right, STG of patients with schizophrenia. Not only neuroanatomical but also neurochemical evidence supports the loss or reversal of normal asymmetry of the temporal lobe in schizophrenia, which might be due to a disruption of the neurodevelopmental processes involved in hemispheric lateralization.
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Affiliation(s)
- O Shirakawa
- Department of Psychiatry and Neurology, Kobe University School of Medicine, Japan
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18
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Perez J, Tardito D. Implications of the cAMP signaling pathway in psychiatric disorders: a systematic review of the evidence. CNS Spectr 2001; 6:294-305. [PMID: 16113628 DOI: 10.1017/s1092852900022008] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
The last decade has seen a shift in the theoretical framework addressing the pathophysiology of psychiatric disorders. During this period, research endeavors have been directed toward investigating the biochemical mechanisms involved in the transduction of information from the cell surface to the cell interior. The emerging picture, supported by growing evidence, is that in addition to neurotransmitters and their receptors, various signal transduction pathways may be linked to the pathophysiology of major psychiatric disorders. In this review, the role of one such pathway--the cyclic adenosine monophosphate (cAMP) signaling pathway--will be highlighted. We review data suggesting the involvement of the upstream and downstream components of this system in the pathophysiology of psychiatric disorders.
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Affiliation(s)
- J Perez
- Department of Neuropsychiatric Sciences, Instituto Scientifico H. San Raffaele, University Vita e Salute, Milan, Italy.
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19
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Avissar S, Barki-Harrington L, Nechamkin Y, Roitman G, Schreiber G. Elevated dopamine receptor-coupled G(s) protein measures in mononuclear leukocytes of patients with schizophrenia. Schizophr Res 2001; 47:37-47. [PMID: 11163543 DOI: 10.1016/s0920-9964(00)00038-4] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Heterotrimeric G proteins play a pivotal role in post-receptor information transduction and were previously implicated in the pathophysiology and treatment of mood disorders. Changes previously detected in G protein levels in post-mortem brain of patients with schizophrenia could reflect effects of antipsychotic medication. The present study aims at quantitatively and functionally evaluating receptor-coupled G proteins in mononuclear leukocytes obtained from 23 untreated patients with schizophrenia and 30 healthy subjects in an attempt to unravel a pattern of G protein measures in schizophrenia distinctive from patterns previously obtained in mood disorders. Dopamine-enhanced guanine nucleotide binding capacity to G(s) protein through D1/D5 receptor in mononuclear leukocytes of untreated patients with schizophrenia was significantly increased in comparison with healthy subjects, and positively correlated with both the total PANSS score and the positive subscale. beta-Adrenergic and muscarinic receptor-coupled G protein functions, as well as G(s)alpha, G(i)alpha and Gbeta immunoreactivities, were similar to healthy subjects. These findings, distinctive for schizophrenia, unrelated to drug treatment, and differential from previous findings in mania and depression, may potentially help to differentially diagnose, after the first psychotic episode, between the major psychoses: schizophrenia and manic-depressive illness.
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Affiliation(s)
- S Avissar
- Department of Clinical Pharmacology, Ben-Gurion University of the Negev, Beer-Sheva 84105, Israel.
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20
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Perez J, Tardito D, Mori S, Racagni G, Smeraldi E, Zanardi R. Abnormalities of cAMP signaling in affective disorders: implication for pathophysiology and treatment. Bipolar Disord 2000; 2:27-36. [PMID: 11254016 DOI: 10.1034/j.1399-5618.2000.020104.x] [Citation(s) in RCA: 45] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
OBJECTIVE During the last decade, much attention has been given to the role of signal transduction pathways in affective disorders. This review describes the possible role of the cAMP signaling in such disorders. METHODS Among the components of cAMP signaling, this review focuses on the cAMP-dependent phosphorylation system. We analyzed the basic components of the cAMP-dependent phosphorylation system and the preclinical evidence supporting their involvement in the biochemical action of antidepressants and mood stabilizers. The clinical data available until now, concerning the possible link between the cAMP-dependent phosphorylation system and the pathophysiology of affective disorders, are also reviewed. RESULTS The studies herein presented demonstrated that the levels and the activity of cAMP-dependent protein kinase are altered by antidepressants and mood stabilizers. Furthermore. these medications are able to modify the phosphorylation state, as well as the levels of some of the cAMP-dependent protein kinase substrates. More recently, clinical studies have reported abnormalities in the cAMP-dependent phosphorylation system in both peripheral cells and the postmortem brain of patients with affective disorders. CONCLUSIONS Overall, these studies support an involvement of cAMP signaling in affective disorders. The precise knowledge of the findings has the potential to improve the understanding of pharmacotherapy and to provide directions for the development of novel biochemical and genetic research strategies on the pathogenesis of affective disorders.
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Affiliation(s)
- J Perez
- Istituto Scientifico H. San Raffaele, Department of Neuropsychiatric Sciences, School of Medicine, University of Milan, Italy.
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21
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Garzón J, Rodríguez-Díaz M, DeAntonio I, DeFelipe J, Rodríguez JR, Sánchez-Blázquez P. Myr+-Gi2 alpha and Go alpha subunits restore the efficacy of opioids, clonidine and neurotensin giving rise to antinociception in G-protein knock-down mice. Neuropharmacology 1999; 38:1861-73. [PMID: 10608281 DOI: 10.1016/s0028-3908(99)00070-2] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
In mice whose Gi/o-protein function had been impaired by antisense 'knock-down' or pertussis toxin treatment, i.c.v. injection of myr+-Gi/o alpha subunits restored the effectiveness of beta-endorphin, morphine, DPDPE, clonidine and neurotensin to produce antinociception. Myr+-G alpha subunits of the class of G-proteins actually impaired were more effective than unlike but related myr+-G alpha subunits. Selectivity was noted in that only exogenous myr+-G alpha subunits affected (enhanced) the activity of agonists in G alpha-deficient signalling systems. This treatment had little effect on agonist potency when the impairment resided at the receptor level. The potential of the opioids, clonidine and R-PIA to increase G alpha-related in vitro hydrolysis of GTP was also re-established after injecting myr+-Gi2 alpha subunits into Gi2-knocked-down mice. Myr+-Gi2 alpha subunits pre-incubated with GTPgammaS or GDPbetaS before i.c.v. injection did not improve the activity of agonists in vivo (antinociception) or in vitro (regulation of low Km GTPase). After impairing the function of PKCbeta1 by antisense treatment or with the inhibitor H7, the effect of myr+-G alpha subunits on agonist potency was prevented. Electron microscope analysis showed the entry of gold-conjugated myr+-G alpha subunits into neural cells. These particles were found in the cytoplasm, associated with the plasma membranes of different neuronal processes and also in synaptic junctions. In cultured neurons and astrocytes myr+-Gi2 alpha-associated fluorescence was internalised in a dose-dependent manner and distributed in the plasma membrane and cytosol, as well as in nuclei of dividing astrocytes. Thus, G alpha subunits in CSF enter into neurons and functionally couple to the receptor-triggered signalling cascade. As G-proteins have been implicated in the pathophysiology of several neural disorders, this finding may be valuable in the therapy of such dysfunctions.
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Affiliation(s)
- J Garzón
- Instituto de Neurobiologia Santiago Ramón y Cajal, Consejo Superior de Investigaciones Cientificas, Madrid, Spain.
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22
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Kaplan GB, Leite-Morris KA, Keith DJ. Differential effects of treatment with typical and atypical antipsychotic drugs on adenylyl cyclase and G proteins. Neurosci Lett 1999; 273:147-50. [PMID: 10515180 DOI: 10.1016/s0304-3940(99)00610-2] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
We examined the effects of chronic in vivo antipsychotic drug treatments on G protein function and regulation. Mice were treated with typical antipsychotic haloperidol (6 mg/kg per day) and atypical agent olanzapine (20 mg/kg per day) for 14 days via mini-osmotic pumps. G protein-activated adenylyl cyclase activity in brain tissues was measured in the presence of guanine nucleotide analogue guanosine-5'-O(3-thiotriphosphate) tetralithium salt, or GTPgammaS. In frontal cortex, haloperidol treatment produced 21% increases in the GTPgammaS -mediated adenylyl cyclase Emax value (vs. vehicle controls) while olanzapine produced 20% reductions in this value (vs. controls); these effects were significant. In striatum, olanzapine treatment produced significant 31 and 27% decreases in Emax values compared with vehicle and haloperidol treatment, respectively. Chronic haloperidol treatment produced significant 24% reductions in the immunoreactivity of cortical, but not striatal, Gialpha1,2 subunits. There were no effects of chronic olanzapine treatment on G(i)alpha1,2 levels and no effects of either antipsychotic on G(s)alpha, levels. Chronic haloperidol and olanzapine treatments differentially regulate G protein-mediated adenylyl cyclase responses in brain regions possibly relating to their unique effects on G protein-coupled receptors.
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Affiliation(s)
- G B Kaplan
- Mental Health and Behavioral Sciences Service, Veterans Affairs Medical Center, Providence, RI 02908, USA.
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23
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Shimon H, Sobolev Y, Davidson M, Haroutunian V, Belmaker RH, Agam G. Inositol levels are decreased in postmortem brain of schizophrenic patients. Biol Psychiatry 1998; 44:428-32. [PMID: 9777173 DOI: 10.1016/s0006-3223(98)00071-7] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
BACKGROUND A previous study reported decreased levels of inositol in frontal cortex of postmortem brain from bipolar patients and suicide victims. The aim of the present study was to test the specificity of this finding. METHODS Inositol and the enzyme that synthesizes it, inositol monophosphatase, were measured in postmortem brain tissue from frontal and occipital cortex and cerebellum from 10 schizophrenic patients and the previously reported controls. Inositol levels were assayed gas-chromatographically as trimethylsilyl derivatives with mannitol as an internal standard. Inositol monophosphatase activity in brain homogenates was measured as the difference between phosphate release from inositol-l-phosphate in the absence and in the presence of Li+. RESULTS Inositol was significantly reduced in all three areas in the schizophrenic patient' brains: inositol monophosphatase was unchanged. Postmortem interval did not correlate with inositol levels and did not differ between control group and schizophrenic patients. CONCLUSIONS These results suggest an abnormality of second messenger precursor availability in common with schizophrenia and affective psychopathology.
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Affiliation(s)
- H Shimon
- Ministry of Health Mental Health Center, Beersheva, Israel
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Dean B, Opeskin K, Pavey G, Hill C, Keks N. Changes in protein kinase C and adenylate cyclase in the temporal lobe from subjects with schizophrenia. J Neural Transm (Vienna) 1998; 104:1371-81. [PMID: 9503283 DOI: 10.1007/bf01294738] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Changes in G-protein linked neurotransmitter receptors have been reported in a number of regions of the brain of schizophrenic subjects. These changes, if functional, could cause a change in proteins such as protein kinase C (PKC) and adenylate cyclase (AC) which are important components of the G-protein linked second messenger cascades. We therefore used autoradiography to measure the distribution and density of [3H]phorbol ester binding to PKC and [3H]forskolin binding to AC in tissue obtained at autopsy from schizophrenic and non-schizophrenic subjects (Controls). There were significant decreases in the density of PKC in the parahippocampal gyrus (687 +/- 60 vs. 885 +/- 51 fmol/mg TE; mean +/- SEM; p < 0.01) and in AC in the dentate gyrus (75 +/- 4.9 vs. 92 +/- 6.5, p < 0.05) from the schizophrenic subjects. These data could indicate that changes in neurotransmitter receptors in the hippocampus from subjects with schizophrenia could have resulted in a change in their associated second messenger systems.
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Affiliation(s)
- B Dean
- Mental Health Research Institute of Victoria, Parkville, Australia
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25
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Kitamura N, Nishino N, Hashimoto T, Kajimoto Y, Shirai Y, Murakami N, Yang CQ, Lin XH, Yamamoto H, Nakai T, Mita T, Komure O, Shirakawa O, Nakai H. Asymmetrical changes in the fodrin alpha subunit in the superior temporal cortices in schizophrenia. Biol Psychiatry 1998; 43:254-62. [PMID: 9513734 DOI: 10.1016/s0006-3223(97)00032-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
BACKGROUND We examined possible abnormalities in neural structural proteins that may underlie morphometric changes reported in the left superior temporal cortices (Brodmann's area 22) of schizophrenics. METHODS Particulate proteins of the superior temporal cortices taken at autopsy from 11 schizophrenic and 9 control brains were fractionated by gel electrophoresis. Target proteins, identified by reading their amino acid sequences, were immunoquantified using the specific antibody. RESULTS Amino acid sequences of the 150-kDa proteins on sodium dodecyl sulfate/polyacrylamide gel electrophoresis, which were significantly increased on the left side of schizophrenic superior temporal cortices, revealed that they were proteolytic fragments of the alpha subunit of fodrin, a major cytoskeletal protein underlying the plasma membrane. Immunoquantification using the specific antibodies against alpha and beta subunits of fodrin indicated that there exist concomitant decreases in the full-length 240-kDa form and increases in the 150-kDa form of alpha-fodrin with no changes of the 235-kDa form of beta-fodrin in the left superior temporal cortices of the schizophrenic brains. CONCLUSIONS The findings may be a possible molecular basis for linking morphometric changes to neurochemical pathophysiology in schizophrenia.
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Affiliation(s)
- N Kitamura
- Department of Psychiatry, Shinko Hospital, Kobe, Japan
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26
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Yang CQ, Kitamura N, Nishino N, Shirakawa O, Nakai H. Isotype-specific G protein abnormalities in the left superior temporal cortex and limbic structures of patients with chronic schizophrenia. Biol Psychiatry 1998; 43:12-9. [PMID: 9442339 DOI: 10.1016/s0006-3223(97)80250-8] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
BACKGROUND The potential role of signal transducing guanine nucleotide-binding regulatory protein (G protein) in schizophrenia is largely unknown. METHODS We immunoquantified isotypes of G protein using specific antisera against alpha and beta subunits of G protein in the superior temporal, prefrontal, and entorhinal cortices as well as the nucleus accumbens and amygdala of postmortem brains from 19 schizophrenic and 28 control subjects. RESULTS In the left hemisphere of schizophrenics, the amount of Gi alpha, Go alpha, and Gq alpha but not that of Gs alpha or G beta decreased in the superior temporal cortex by 27%, 27%, and 16%, respectively, as compared with the values in ipsilateral controls; the amount of any G protein isotype in the prefrontal and entorhinal cortices was not changed. In the nucleus accumbens and amygdala, the paranoid type schizophrenics showed a smaller amount of Gi alpha and Go alpha than the disorganized type schizophrenics. In the right superior temporal cortex, the isotype amount did not differ between the schizophrenic and control groups. CONCLUSIONS The decreased Gq alpha immunoreactivity in the schizophrenic left superior temporal cortex may reflect the down-regulation of Gq alpha, resulting from chronic stimulation of Gq alpha-coupled receptors, while the decreased Gi alpha and Go alpha in the nucleus accumbens and amygdala of paranoid type schizophrenics may be related to the dopaminergic hyperactivity via dopamine D2 receptors.
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Affiliation(s)
- C Q Yang
- Department of Psychiatry and Neurology, Kobe University School of Medicine, Japan
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27
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Abstract
Neurobiological research in schizophrenia has been hampered by several confounding factors such as the heterogeneity of the illness and the paucity of biological markers. Recent progress in research methods, however, has enabled the improvement in our understanding its pathophysiology. This paper reviews recent neurochemical investigations of schizophrenia and its animal models which were conducted in Japan in the last decade. The research areas reviewed are (i) monoamine and their metabolites in body fluids, (ii) phospholipids and prostaglandins, (iii) neurochemistry in autopsy brains, (iv) immunological measures, (v) magnetic resonance spectroscopy, (vi) regional cerebral blood flows (rCBF), (vii) molecular genetics, and (viii) animal models. It is worth noting that there exist abnormalities of amino acidergic (glutamatergic and GABAergic) neurotransmission as well as monoaminergic (dopaminergic and serotonergic) one in postmortem schizophrenic brains. These abnormalities and also the findings of altered rCBF indicate the existence of disturbed neuronal circuits that contribute to the diverse symptoms of schizophrenia. Also, dysfunction of membrane phospholipids derived from studies on magnetic resonance spectroscopy may underlie negative symptoms in schizophrenia. Given that schizophrenia is considered to comprise a group of disorders with a diverse heterogeneity of etiologies, research in the next decade is expected to identify putative genes that are involved in vulnerability to schizophrenic phenotype.
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Affiliation(s)
- S Otsuki
- Zikei Institute of Psychiatry, Okayama, Japan
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Lowther S, Katona CL, Crompton MR, Horton RW. Brain [3H]cAMP binding sites are unaltered in depressed suicides, but decreased by antidepressants. Brain Res 1997; 758:223-8. [PMID: 9203552 DOI: 10.1016/s0006-8993(97)00232-1] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Saturation binding of [3H]cAMP to the regulatory subunit of cAMP-dependent protein kinase (PKA) was measured in the soluble fraction of brain samples, obtained at post-mortem, from suicides with a firm retrospective diagnosis of depression and individually matched controls. Suicides were subdivided into those who had been free of antidepressant drugs for at least 3 months and those in whom prescription of antidepressants was clearly documented. In antidepressant-free suicides, we found no significant differences in the number or affinity of [3H]cAMP binding sites in the five regions studied. In antidepressant-treated suicides however, Bmax values were lower in all regions, reaching statistical significance in parietal cortex and amygdala. Kd values for antidepressant-treated suicides were significantly higher in parietal cortex, temporal cortex and amygdala. These results suggest the regulatory subunit of PKA is unaltered in depression, but is influenced by antidepressant drugs.
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Affiliation(s)
- S Lowther
- Department of Pharmacology and Clinical Pharmacology, St. George's Hospital Medical School, London, UK.
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Opeskin K, Dean B, Pavey G, Hill C, Keks N, Copolov D. Neither protein kinase C nor adenylate cyclase are altered in the striatum from subjects with schizophrenia. Schizophr Res 1996; 22:159-64. [PMID: 8958600 DOI: 10.1016/s0920-9964(96)00065-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Dopamine (DA) D2 receptors which act by modulating second messenger pathways that include protein kinase C (PKC) and adenylate cyclase (AC) have been repeatedly shown to be increased in striatum from subjects with schizophrenia. Therefore it seemed possible that chronic up-regulation of DA-D2 receptors in the schizophrenic brain could result in a change in either of these two proteins. Hence we measured PKC and AC in striatum from 20 schizophrenic subjects and 20 non-schizophrenic subjects by quantitative autoradiography and could show no difference in the density of either PKC (436 +/- 35 vs. 485 +/- 29 fmol/mg tissue equivalents (TE), mean +/- SEM) or AC (77 +/- 9 vs. 80 +/- 7 fmol/mg TE) in the tissue from schizophrenic compared to the non-schizophrenic subjects. Thus, these data do not support the hypothesis that PKC or AC are changed in the schizophrenic brain.
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Affiliation(s)
- K Opeskin
- Rebecca L. Cooper Laboratories, Mental Health Research Institute of Victoria, Parkville, Australia
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30
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Okada F, Tokumitsu Y, Takahashi N, Crow TJ, Roberts GW. Reduced concentrations of the alpha-subunit of GTP-binding protein Go in schizophrenic brain. J Neural Transm (Vienna) 1994; 95:95-104. [PMID: 7865171 DOI: 10.1007/bf01276428] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Concentrations of the alpha-subunits of GTP-binding protein, Go (Go alpha) and of Gi2 (Gi2 alpha) in 6 areas (the hippocampus, parahippocampus, putamen, caudate head, orbital frontal cortex, and lateral temporal cortex) of control and schizophrenic postmortem brains were investigated using the highly sensitive enzyme immunoassay method. There was a significant decrease in Go alpha in the hippocampus and caudate head of the right hemisphere in schizophrenic patients compared to controls; the ANOVA (a general linear model; SAS Type II) demonstrated a significant diagnosis x side interaction only in the hippocampus. In other areas of the brain, analysis by grouping under diagnosis, side, age, gender, and postmortem delay showed no significant deviations in Go alpha between controls and schizophrenics. The concentrations of Gi2 alpha did not differ significantly in any area. These findings contrasted with the results yielded by ADP-ribosylation, which showed decreased pertussis toxin ADP-ribosylated amounts in the hippocampus and putamen of the contralateral (left) hemisphere. Some abnormal receptor-Go or Gi 1 signalling in hippocampus, putamen or caudate head may be involved in the pathogenesis of schizophrenia.
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Affiliation(s)
- F Okada
- Health Administration Center, Sapporo, Japan
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