401
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Abstract
Depression and suicidal behavior have recently been shown to be associated with disturbances in structural and synaptic plasticity. Brain-derived neurotrophic factor (BDNF), one of the major neurotrophic factors, plays an important role in the maintenance and survival of neurons and in synaptic plasticity. Several lines of evidence suggest that BDNF is involved in depression, such that the expression of BDNF is decreased in depressed patients. In addition, antidepressants up-regulate the expression of BDNF. This has led to the proposal of the "neurotrophin hypothesis of depression". Increasing evidence demonstrates that suicidal behavior is also associated with lower expression of BDNF, which may be independent from depression. Recent genetic studies also support a link of BDNF to depression/suicidal behavior. Not only BDNF, but abnormalities in its cognate receptor tropomycin receptor kinase B (TrkB) and its splice variant (TrkB.T1) have also been reported in depressed/suicidal patients. It has been suggested that epigenetic modulation of the Bdnf and Trkb genes may contribute to their altered expression and functioning. More recently, impairment in the functioning of pan75 neurotrophin receptor has been reported in suicide brain specimens. pan75 neurotrophin receptor is a low-affinity neurotrophin receptor that, when expressed in conjunction with low availability of neurotropins/Trks, induces apoptosis. Overall, these studies suggest the possibility that BDNF and its mediated signaling may participate in the pathophysiology of depression and suicidal behavior. This review focuses on the critical evidence demonstrating the involvement of BDNF in depression and suicide.
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Affiliation(s)
- Yogesh Dwivedi
- Psychiatric Institute, Department of Psychiatry, College of Medicine, University of Illinois at Chicago, Chicago, Illinois, USA.
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402
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Sequeira A, Mamdani F, Ernst C, Vawter MP, Bunney WE, Lebel V, Rehal S, Klempan T, Gratton A, Benkelfat C, Rouleau GA, Mechawar N, Turecki G. Global brain gene expression analysis links glutamatergic and GABAergic alterations to suicide and major depression. PLoS One 2009; 4:e6585. [PMID: 19668376 PMCID: PMC2719799 DOI: 10.1371/journal.pone.0006585] [Citation(s) in RCA: 271] [Impact Index Per Article: 18.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2008] [Accepted: 05/04/2009] [Indexed: 01/19/2023] Open
Abstract
BACKGROUND Most studies investigating the neurobiology of depression and suicide have focused on the serotonergic system. While it seems clear that serotonergic alterations play a role in the pathogenesis of these major public health problems, dysfunction in additional neurotransmitter systems and other molecular alterations may also be implicated. Microarray expression studies are excellent screening tools to generate hypotheses about additional molecular processes that may be at play. In this study we investigated brain regions that are known to be implicated in the neurobiology of suicide and major depression are likely to represent valid global molecular alterations. METHODOLOGY/PRINCIPAL FINDINGS We performed gene expression analysis using the HG-U133AB chipset in 17 cortical and subcortical brain regions from suicides with and without major depression and controls. Total mRNA for microarray analysis was obtained from 663 brain samples isolated from 39 male subjects, including 26 suicide cases and 13 controls diagnosed by means of psychological autopsies. Independent brain samples from 34 subjects and animal studies were used to control for the potential confounding effects of comorbidity with alcohol. Using a Gene Ontology analysis as our starting point, we identified molecular pathways that may be involved in depression and suicide, and performed follow-up analyses on these possible targets. Methodology included gene expression measures from microarrays, Gene Score Resampling for global ontological profiling, and semi-quantitative RT-PCR. We observed the highest number of suicide specific alterations in prefrontal cortical areas and hippocampus. Our results revealed alterations of synaptic neurotransmission and intracellular signaling. Among these, Glutamatergic (GLU) and GABAergic related genes were globally altered. Semi-quantitative RT-PCR results investigating expression of GLU and GABA receptor subunit genes were consistent with microarray data. CONCLUSIONS/SIGNIFICANCE The observed results represent the first overview of global expression changes in brains of suicide victims with and without major depression and suggest a global brain alteration of GLU and GABA receptor subunit genes in these conditions.
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Affiliation(s)
- Adolfo Sequeira
- McGill Group for Suicide Studies, Douglas Mental Health University Institute, McGill University, Montreal, Quebec, Canada
| | - Firoza Mamdani
- McGill Group for Suicide Studies, Douglas Mental Health University Institute, McGill University, Montreal, Quebec, Canada
| | - Carl Ernst
- McGill Group for Suicide Studies, Douglas Mental Health University Institute, McGill University, Montreal, Quebec, Canada
| | - Marquis P. Vawter
- Department of Psychiatry and Human Behavior, School of Medicine, University of California Irvine, Irvine, California, United States of America
| | - William E. Bunney
- Department of Psychiatry and Human Behavior, School of Medicine, University of California Irvine, Irvine, California, United States of America
| | - Veronique Lebel
- McGill Group for Suicide Studies, Douglas Mental Health University Institute, McGill University, Montreal, Quebec, Canada
| | - Sonia Rehal
- McGill Group for Suicide Studies, Douglas Mental Health University Institute, McGill University, Montreal, Quebec, Canada
| | - Tim Klempan
- McGill Group for Suicide Studies, Douglas Mental Health University Institute, McGill University, Montreal, Quebec, Canada
| | - Alain Gratton
- McGill Group for Suicide Studies, Douglas Mental Health University Institute, McGill University, Montreal, Quebec, Canada
| | - Chawki Benkelfat
- Royal Victoria Hospital, McGill University, Montreal, Quebec, Canada
| | - Guy A. Rouleau
- Ste Justine Hospital, Université de Montréal, Montreal, Quebec, Canada
| | - Naguib Mechawar
- McGill Group for Suicide Studies, Douglas Mental Health University Institute, McGill University, Montreal, Quebec, Canada
| | - Gustavo Turecki
- McGill Group for Suicide Studies, Douglas Mental Health University Institute, McGill University, Montreal, Quebec, Canada
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403
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Llorente R, Llorente-Berzal A, Petrosino S, Marco EM, Guaza C, Prada C, López-Gallardo M, Di Marzo V, Viveros MP. Gender-dependent cellular and biochemical effects of maternal deprivation on the hippocampus of neonatal rats: a possible role for the endocannabinoid system. Dev Neurobiol 2009; 68:1334-47. [PMID: 18666205 DOI: 10.1002/dneu.20666] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Adult animals submitted to a single prolonged episode of maternal deprivation (MD) [24 h, postnatal days (PND) 9-10] show behavioral alterations that resemble specific symptoms of schizophrenia. These behavioral impairments may be related to neuronal loss in the hippocampus triggered by elevated glucocorticoids. Furthermore, our previous data suggested functional relationships between MD stress and the endocannabinoid system. In this study, we addressed the effects of MD on hippocampal glial cells and the possible relationship with changes in plasma corticosterone (CORT) levels. In addition, we investigated the putative involvement of the endocannabinoid system by evaluating (a) the effects of MD on hippocampal levels of endocannabinoids (b) The modulation of MD effects by two inhibitors of endocannabinoids inactivation, the fatty acid amide hydrolase inhibitor N-arachidonoyl-serotonin (AA-5-HT), and the endocannabinoid reuptake inhibitor, OMDM-2. Drug treatments were administered once daily from PND 7 to PND 12 at a dose of 5 mg/kg, and the animals were sacrificed at PND 13. MD induced increased CORT levels in both genders. MD males also showed an increased number of astrocytes in CA1 and CA3 areas and a significant increase in hippocampal 2-arachidonoylglycerol. The cannabinoid compounds reversed the endocrine and cellular effects of maternal deprivation. We provide direct evidence for gender-dependent cellular and biochemical effects of MD on developmental hippocampus, including changes in the endocannabinoid system.
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Affiliation(s)
- Ricardo Llorente
- Departamento de Fisiología (Fisiología Animal II), Facultad de Biología, Universidad Complutense, Madrid, Spain
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404
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Hercher C, Turecki G, Mechawar N. Through the looking glass: examining neuroanatomical evidence for cellular alterations in major depression. J Psychiatr Res 2009; 43:947-61. [PMID: 19233384 DOI: 10.1016/j.jpsychires.2009.01.006] [Citation(s) in RCA: 112] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/28/2008] [Revised: 01/10/2009] [Accepted: 01/16/2009] [Indexed: 02/03/2023]
Abstract
Alterations in brain plasticity are increasingly thought to play important roles in major depressive disorder (MDD) and suicide. To gain a better understanding of the gross structural changes observed in the brains of major depressed and suicide subjects, a number of recent investigations have scrutinized the cellular integrity of brain regions implicated in mood disorders. The purpose of this review is to summarize the current knowledge on the microscopic features of neuronal and glial cell populations in these different brain regions, namely the prefrontal cortex, hippocampus, amygdala, raphe nucleus and locus coeruleus. In general, evidence from this burgeoning field supports the hypothesis of altered cell plasticity in MDD and suicide occurring mainly in key fronto-limbic areas. Interestingly, reported morphometric and cell density alterations are generally region-specific and implicate several neuromodulatory systems, notably GABAergic, serotonergic, noradrenergic and glutamatergic pathways. Cell-specific changes involve reductions in densities of astrocytes and oligodendrocytes, while increases in microglial densities have also been reported. Furthermore, increases in neuronal densities have been found in subcortical regions. The implication of such findings for our understanding of the cellular and molecular underpinnings of MDD and suicide are discussed, and the strengths and weaknesses of morphological approaches used to analyse human postmortem brain tissues are evaluated.
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Affiliation(s)
- Christa Hercher
- McGill Group for Suicide Studies, Douglas Mental Health University Institute, Québec, Canada
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405
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Machado-Vieira R, Manji HK, Zarate CA. The role of the tripartite glutamatergic synapse in the pathophysiology and therapeutics of mood disorders. Neuroscientist 2009; 15:525-39. [PMID: 19471044 DOI: 10.1177/1073858409336093] [Citation(s) in RCA: 112] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Bipolar disorder and major depressive disorder are common, chronic, and recurrent mood disorders that affect the lives of millions of individuals worldwide. Growing evidence suggests that glutamatergic system dysfunction is directly involved in mood disorders. This article describes the role of the "tripartite glutamatergic synapse," comprising presynaptic and postsynaptic neurons and glial cells, in the pathophysiology and therapeutics of mood disorders. Glutamatergic neurons and glia directly control synaptic and extrasynaptic glutamate levels/ release through integrative effects that target glutamate excitatory amino acid transporters, postsynaptic density proteins, ionotropic receptors (alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid [AMPA], N-methyl-D-aspartate [NMDA], and kainate), and metabotropic receptors. This article also explores the glutamatergic modulators riluzole and ketamine, which are considered valuable proof-of-concept agents for developing the next generation of antidepressants and mood stabilizers. In therapeutically relevant paradigms, ketamine preferentially targets postsynaptic AMPA/NMDA receptors, and riluzole preferentially targets presynaptic voltage-operated channels and glia.
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Affiliation(s)
- Rodrigo Machado-Vieira
- Experimental Therapeutics, Mood and Anxiety Disorders Research Program, NIMH-NIH, Bethesda, Maryland 20892, USA
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406
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Krystal JH, Tolin DF, Sanacora G, Castner SA, Williams GV, Aikins DE, Hoffman RE, D'Souza DC. Neuroplasticity as a target for the pharmacotherapy of anxiety disorders, mood disorders, and schizophrenia. Drug Discov Today 2009; 14:690-7. [PMID: 19460458 DOI: 10.1016/j.drudis.2009.05.002] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2009] [Accepted: 05/08/2009] [Indexed: 12/12/2022]
Abstract
Current treatments for psychiatric disorders were developed with the aim of providing symptomatic relief rather than reversing underlying abnormalities in neuroplasticity or neurodevelopment that might contribute to psychiatric disorders. This review considers the possibility that psychiatric treatments might be developed that target neuroplasticity deficits or that manipulate neuroplasticity in novel ways. These treatments might not provide direct symptomatic relief. However, they might complement or enhance current pharmacotherapies and psychotherapies aimed at the prevention and treatment of psychiatric disorders. In considering neuroplasticity as a target for the treatment of psychiatric disorders, we build on exciting new findings in the areas of anxiety disorders, mood disorders, and schizophrenia.
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Affiliation(s)
- John H Krystal
- Department of Psychiatry, Yale University School of Medicine, New Haven, CT 06510, United States.
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407
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Miller AH, Maletic V, Raison CL. Inflammation and its discontents: the role of cytokines in the pathophysiology of major depression. Biol Psychiatry 2009; 65:732-41. [PMID: 19150053 PMCID: PMC2680424 DOI: 10.1016/j.biopsych.2008.11.029] [Citation(s) in RCA: 2597] [Impact Index Per Article: 173.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/23/2008] [Revised: 11/26/2008] [Accepted: 11/26/2008] [Indexed: 02/06/2023]
Abstract
Recognition that inflammation may represent a common mechanism of disease has been extended to include neuropsychiatric disorders including major depression. Patients with major depression have been found to exhibit increased peripheral blood inflammatory biomarkers, including inflammatory cytokines, which have been shown to access the brain and interact with virtually every pathophysiologic domain known to be involved in depression, including neurotransmitter metabolism, neuroendocrine function, and neural plasticity. Indeed, activation of inflammatory pathways within the brain is believed to contribute to a confluence of decreased neurotrophic support and altered glutamate release/reuptake, as well as oxidative stress, leading to excitotoxicity and loss of glial elements, consistent with neuropathologic findings that characterize depressive disorders. Further instantiating the link between inflammation and depression are data demonstrating that psychosocial stress, a well-known precipitant of mood disorders, is capable of stimulating inflammatory signaling molecules, including nuclear factor kappa B, in part, through activation of sympathetic nervous system outflow pathways. Interestingly, depressed patients with increased inflammatory biomarkers have been found to be more likely to exhibit treatment resistance, and in several studies, antidepressant therapy has been associated with decreased inflammatory responses. Finally, preliminary data from patients with inflammatory disorders, as well as medically healthy depressed patients, suggest that inhibiting proinflammatory cytokines or their signaling pathways may improve depressed mood and increase treatment response to conventional antidepressant medication. Translational implications of these findings include the unique opportunity to identify relevant patient populations, apply immune-targeted therapies, and monitor therapeutic efficacy at the level of the immune system in addition to behavior.
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Affiliation(s)
- Andrew H Miller
- Department of Psychiatry and Behavioral Sciences, Emory University School of Medicine, Atlanta, Georgia 30322, USA.
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408
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A potential role for pro-inflammatory cytokines in regulating synaptic plasticity in major depressive disorder. Int J Neuropsychopharmacol 2009; 12:561-78. [PMID: 19224657 PMCID: PMC2771334 DOI: 10.1017/s1461145709009924] [Citation(s) in RCA: 230] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
A growing body of data suggests that hyperactivation of the immune system has been implicated in the pathophysiology of major depressive disorder (MDD). Several pro-inflammatory cytokines, such as tumour necrosis factor-alpha (TNF-alpha) and interleukin-1 (IL-1) have been found to be significantly increased in patients with MDD. This review focuses on these two cytokines based on multiple lines of evidence from genetic, animal behaviour, and clinical studies showing that altered levels of serum TNF-alpha and IL-1 are associated with increased risk of depression, cognitive impairments, and reduced responsiveness to treatment. In addition, recent findings have shown that centrally expressed TNF-alpha and IL-1 play a dual role in the regulation of synaptic plasticity. In this paper, we review and critically appraise the mechanisms by which cytokines regulate synaptic and neural plasticity, and their implications for the pathophysiology and treatment of MDD. Finally, we discuss the therapeutic potential of anti-inflammatory-based approaches for treating patients with severe mood disorders. This is a promising field for increasing our understanding of the mechanistic interaction between the immune system, synaptic plasticity, and antidepressants, and for the ultimate development of novel and improved therapeutics for severe mood disorders.
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409
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Orre K, Wennström M, Tingström A. Chronic lithium treatment decreases NG2 cell proliferation in rat dentate hilus, amygdala and corpus callosum. Prog Neuropsychopharmacol Biol Psychiatry 2009; 33:503-10. [PMID: 19439244 DOI: 10.1016/j.pnpbp.2009.01.015] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/03/2008] [Revised: 01/28/2009] [Accepted: 01/28/2009] [Indexed: 11/18/2022]
Abstract
An increasing number of investigations suggest volumetric changes and glial pathology in several brain regions of patients with bipolar disorder. Lithium, used in the treatment of this disorder, has been reported to be neuroprotective and increase brain volume. Here we investigate the effect of lithium on the proliferation and survival of glial cells positive for the chondroitin sulphate proteoglycan NG2 (NG2 cells); a continuously dividing cell type implicated in remyelination and suggested to be involved in regulation of neuronal signaling and axonal outgrowth. Adult male rats were treated with lithium for four weeks and injected with the proliferation marker bromodeoxyuridine (BrdU) before or at the end of the treatment period. Immunohistochemical analysis of brain sections was performed to estimate the number of newly born (BrdU-labeled) NG2 cells and oligodendrocytes in hippocampus, basolateral nuclei of amygdala and corpus callosum. Lithium significantly decreased the proliferation of NG2 cells in dentate hilus of hippocampus, amygdala and corpus callosum, but not in the molecular layer or the cornu ammonis (CA) regions of hippocampus. The effect was more pronounced in the corpus callosum. No effect of lithium on the survival of newborn cells or the number of newly generated oligodendrocytes could be detected. Our results demonstrate that in both white and gray matter brain regions implicated in the pathophysiology of bipolar disorder, chronic lithium treatment significantly decreases the proliferation rate of NG2 cells; the major proliferating cell type of the adult brain.
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Affiliation(s)
- Karin Orre
- Molecular Psychiatry Unit, Wallenberg Neuroscience Center, BMC B12, S-221 84 Lund, Sweden
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410
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Venkatraman TN, Krishnan KRR, Steffens DC, Song AW, Taylor WD. Biochemical abnormalities of the medial temporal lobe and medial prefrontal cortex in late-life depression. Psychiatry Res 2009; 172:49-54. [PMID: 19179054 PMCID: PMC2659332 DOI: 10.1016/j.pscychresns.2008.07.001] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/18/2007] [Revised: 05/01/2008] [Accepted: 07/04/2008] [Indexed: 11/24/2022]
Abstract
We utilized single-voxel (1)H magnetic resonance spectroscopy (MRS) to investigate biochemical abnormalities related to late-life depression in the medial prefrontal cortex and medial temporal lobe. Fourteen elderly subjects whose depression responded to treatment and 12 nondepressed subjects were enrolled. Subjects were scanned using a GE 3.0 Tesla whole body MR scanner. Metabolite concentrations were quantified using the LC Model software and adjusted for CSF and ratio of gray to white matter. ANCOVA models tested for group differences while controlling for age and sex. Older previously depressed individuals showed significantly reduced concentrations of total N-acetyl aspartate (NAA), choline, and creatine in the prefrontal cortex and significantly elevated left medial temporal lobe concentrations of NAA and myo-inositol. There were no significant group differences in right temporal metabolite concentrations. The prefrontal cortex observations suggest that reduced neuronal, phospolipid, and energy metabolism is present even in clinically improved depression. In contrast, elevated NAA and myo-inositol concentrations in the left medial temporal lobe could be associated with neuronal and glial cell changes in the amygdala.
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Affiliation(s)
- T. N. Venkatraman
- Department of Radiology, Duke University Medical Center, Durham, NC, The Brain Imaging and Analysis Center, Duke University Medical Center, Durham, NC
| | - K. Ranga R. Krishnan
- Department of Psychiatry, Duke University Medical Center, Durham, NC, The Duke-NUS Graduate Medical School Singapore
| | - David C. Steffens
- Department of Psychiatry, Duke University Medical Center, Durham, NC
| | - Allen W. Song
- Department of Psychiatry, Duke University Medical Center, Durham, NC, Department of Radiology, Duke University Medical Center, Durham, NC, The Brain Imaging and Analysis Center, Duke University Medical Center, Durham, NC
| | - Warren D. Taylor
- Department of Psychiatry, Duke University Medical Center, Durham, NC,Corresponding author: Warren D. Taylor, MD, Department of Psychiatry and Behavioral Sciences, Duke University Medical Center, DUMC Box 3903, Durham, NC 27710, P: (919) 668-7887, F: (919) 681-7668,
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411
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Mayberg HS. Targeted electrode-based modulation of neural circuits for depression. J Clin Invest 2009; 119:717-25. [PMID: 19339763 DOI: 10.1172/jci38454] [Citation(s) in RCA: 318] [Impact Index Per Article: 21.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
During the last 20 years of neuroscience research, we have witnessed a fundamental shift in the conceptualization of psychiatric disorders, with the dominant psychological and neurochemical theories of the past now complemented by a growing emphasis on developmental, genetic, molecular, and brain circuit models. Facilitating this evolving paradigm shift has been the growing contribution of functional neuroimaging, which provides a versatile platform to characterize brain circuit dysfunction underlying specific syndromes as well as changes associated with their successful treatment. Discussed here are converging imaging findings that established a rationale for testing a targeted neuromodulation strategy, deep brain stimulation, for treatment-resistant major depression.
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Affiliation(s)
- Helen S Mayberg
- Department of Psychiatry and Department of Neurology, Emory University School of Medicine, Atlanta, Georgia 30322, USA.
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412
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Valentine GW, Sanacora G. Targeting glial physiology and glutamate cycling in the treatment of depression. Biochem Pharmacol 2009; 78:431-9. [PMID: 19376090 DOI: 10.1016/j.bcp.2009.04.008] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2009] [Revised: 03/23/2009] [Accepted: 04/09/2009] [Indexed: 12/21/2022]
Abstract
Accumulating evidence indicates that dysfunction in amino acid neurotransmission contributes to the pathophysiology of depression. Consequently, the modulation of amino acid neurotransmission represents a new strategy for antidepressant development. While glutamate receptor ligands are known to have antidepressant effects, mechanisms regulating glutamate cycling and metabolism may be viable drug targets as well. In particular, excitatory amino acid transporters (EAATs) that are embedded in glial processes constitute the primary means of clearing extrasynaptic glutamate. Therefore, the decreased glial number observed in preclinical stress models, and in postmortem tissue from depressed patients provides intriguing, yet indirect evidence for a role of disrupted glutamate homeostasis in the pathophysiology of depression. More direct evidence for this hypothesis comes from studies using magnetic resonance spectroscopy (MRS), a technique that non-invasively measures in vivo concentrations of glutamate and other amino acids under different experimental conditions. Furthermore, when combined with the infusion of (13)C-labeled metabolic precursors, MRS can measure flux through discrete metabolic pathways. This approach has recently shown that glial amino acid metabolism is reduced by chronic stress, an effect that provides a link between environmental stress and the decreased EAAT activity observed under conditions of increased oxidative stress in the brain. Furthermore, administration of riluzole, a drug that enhances glutamate uptake through EAATs, reversed this stress-induced change in glial metabolism. Because riluzole has antidepressant effects in both animal models and human subjects, it may represent the prototype for a novel class of antidepressants with the modulation of glial physiology as a primary mechanism of action.
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Affiliation(s)
- Gerald W Valentine
- Yale University, Department of Psychiatry, CNRU, 34 Park Street, New Haven, CT 06508, USA
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413
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Increased phospholipase A2 activity and inflammatory response but decreased nerve growth factor expression in the olfactory bulbectomized rat model of depression: effects of chronic ethyl-eicosapentaenoate treatment. J Neurosci 2009; 29:14-22. [PMID: 19129380 DOI: 10.1523/jneurosci.3569-08.2009] [Citation(s) in RCA: 121] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
An increased inflammatory response and deficient synthesis of neurotrophic factors (NTFs) may contribute to the etiology of depression. However, the interrelationship between inflammation and NTFs is unknown. Recently, ethyl-eicosapentaenoate (EPA) has been used to treat depression. The mechanism by which EPA benefits depression is also unclear. Using the olfactory bulbectomized (OB) rat model of depression, this study evaluated two pathways from bulbectomy to the induction of depression-like changes (the inflammation-hypothalamic-pituitary-adrenal axis-stress response pathway and inflammation-nerve growth factor-memory pathway) and the effect of EPA on these pathways. When compared with sham-operated rats fed a control diet, significantly increased locomotor and rearing activities in an "open field," impaired memory in the Morris water maze, increased expression of corticotrophin-releasing factor (CRF), and increased secretion of corticosterone were found in OB rats. mRNA expression of nerve growth factor (NGF) was significantly lower in the hippocampus, and phospholipase A2 (PLA2) was higher in the hypothalamus; this change was associated with increased interleukin-1beta (IL-1beta) and prostaglandin E2 (PGE2) in the serum and brain. EPA treatments normalized these behavioral impairments and reduced CRF expression and corticosterone secretion. EPA also reduced serum concentrations of IL-1beta and PGE2, but reversed NGF reduction. Similar to the effects of EPA, the anti-inflammatory drug celecoxib significantly reduced blood PGE2, IL-1beta, and corticosterone concentrations and increased NGF expression in OB rats. Furthermore, anti-NGF treatment blocked EPA effects on behavior. These results suggest that an interaction exists between inflammation and NGF in the depression model. EPA may improve depression via its anti-inflammation properties and the upregulation of NGF.
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414
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Early maternal deprivation in rats induces gender‐dependent effects on developing hippocampal and cerebellar cells. Int J Dev Neurosci 2009; 27:233-41. [DOI: 10.1016/j.ijdevneu.2009.01.002] [Citation(s) in RCA: 82] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2008] [Revised: 12/31/2008] [Accepted: 01/13/2009] [Indexed: 11/19/2022] Open
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415
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Cytoprotective effect of lithium against spontaneous and induced apoptosis of lymphoid cell line MOLT-4. Folia Histochem Cytobiol 2009; 47:639-46. [PMID: 20430733 DOI: 10.2478/v10042-009-0118-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Lithium (Li) is still useful in the treatment of bipolar disorder. Cellular mechanisms of Li action are not fully understood and include some cytoprotective properties. Data concerning Li effect on the apoptotic mechanisms in cells other than neurons are fragmentary and contradictory. We have investigated anti-apoptotic activity of Li in a lymphoid derived MOLT-4 cell line. Spontaneous and camptothecin-induced apoptosis was analyzed in cells treated with 0-20 mM Li carbonate. Early apoptosis was identified as significant mitochondrial depolarization (JC-1 staining). Later stages of apoptosis were estimated with annexin V binding and by the proportion of cells containing sub-G1 amounts of DNA (PI staining). We have observed a biphasic effect of Li on the proportion of spontaneously apoptotic cells;namely, low (therapeutic) concentrations of Li had a significant effect stabilizing the mitochondrial membrane polarization, while 10 and 20mM Li increased apoptosis. The latter could be seen both as mitochondrial depolarization as well as an increased proportion of sub-G1 cells, accompanied by reduced proportion of S phase cells. Li at concentrations above 2 mM had a significant, dose-dependent, anti-apoptotic effect on the cells undergoing camptothecin induced apoptosis. In conclusion, demonstrated cytoprotective effect of Li is at least partially related to stabilization of mitochondrial membrane potential and to the reduction of DNA damaging effects in proliferating cells; both may form part of the mechanism through which Li is useful in therapy of bipolar disorder, but may have more general consequences.
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416
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Pittenger C, Coric V, Banasr M, Bloch M, Krystal JH, Sanacora G. Riluzole in the treatment of mood and anxiety disorders. CNS Drugs 2008; 22:761-86. [PMID: 18698875 DOI: 10.2165/00023210-200822090-00004] [Citation(s) in RCA: 118] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Recent advances implicate amino acid neurotransmission in the pathophysiology and treatment of mood and anxiety disorders. Riluzole, which is approved and marketed for the treatment of amyotrophic lateral sclerosis, is thought to be neuroprotective through its modulation of glutamatergic neurotransmission. Riluzole has multiple molecular actions in vitro; the two that have been documented to occur at physiologically realistic drug concentrations and are therefore most likely to be clinically relevant are inhibition of certain voltage-gated sodium channels, which can lead to reduced neurotransmitter release, and enhanced astrocytic uptake of extracellular glutamate.Although double-blind, placebo-controlled trials are lacking, several open-label trials have suggested that riluzole, either as monotherapy or as augmentation of standard therapy, reduces symptoms of obsessive-compulsive disorder, unipolar and bipolar depression, and generalized anxiety disorder. In studies of psychiatrically ill patients conducted to date, the drug has been quite well tolerated; common adverse effects include nausea and sedation. Elevation of liver function tests is common and necessitates periodic monitoring, but has been without clinical consequence in studies conducted to date in psychiatric populations. Case reports suggest utility in other conditions, including trichotillomania and self-injurious behaviour associated with borderline personality disorder. Riluzole may hold promise for the treatment of several psychiatric conditions, possibly through its ability to modulate pathologically dysregulated glutamate levels, and merits further investigation.
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Affiliation(s)
- Christopher Pittenger
- Clinical Neuroscience Research Unit, Yale University School of Medicine, New Haven, Connecticut, USA.
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417
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Byne W, Tatusov A, Yiannoulos G, Vong GS, Marcus S. Effects of mental illness and aging in two thalamic nuclei. Schizophr Res 2008; 106:172-81. [PMID: 18835520 PMCID: PMC2629743 DOI: 10.1016/j.schres.2008.08.023] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/06/2008] [Revised: 08/06/2008] [Accepted: 08/11/2008] [Indexed: 12/15/2022]
Abstract
We previously reported a schizophrenia associated reduction of neuronal and oligodendrocyte number in the anterior principal thalamic nucleus (APN) in a cohort of severely impaired elderly subjects with schizophrenia (SZ) relative to age matched nonpsychiatric controls (NCs). The present study was undertaken to determine 1) if those findings could be replicated in an independent sample of less chronically impaired subjects with SZ and NCs stratified across a broader age range; 2) if the findings are specific to SZ or are also seen in unipolar major depressive (MDD) or bipolar disorder (BPD); and 3) if the findings are specific to the APN or also seen in another thalamic nucleus. Computer assisted stereological methods were employed to determine the number of neurons and oligodendrocytes in the APN and centromedian nucleus (CMN) of the Nissl-stained thalamic sections maintained by the Stanley Foundation Brain Bank. This collection includes specimens from NCs and age matched subjects with diagnoses of SZ, MDD, or BPD who died between the ages of 25 and 68. Data were analyzed by mixed-effects linear regressions adjusting for demographic variables and known history of exposure to psychotropic medications. Oligodendrocyte number was decreased in both nuclei relative to NCs in subjects with SZ and in that subset of subjects with BPD who had experienced psychotic episodes. Compared to NCs both of these patient groups also exhibited an attenuation of an age-related increase in the number of oligodendrocytes. Contrary to our previous report, we did not detect a SZ-associated deficit in neuronal number in the APN. A history of exposure to neuroleptics, however, was associated with a decrease in neuronal number in both nuclei, but this decrease did not vary in relation to cumulative lifetime neuroleptic exposure in fluphenazine equivalents. Among subjects with psychiatric diagnoses, exposure to lithium was associated with an increase in the number of oligodendrocytes. No effects were detected for exposure to anticonvulsants or for abuse of alcohol or other substances.
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Affiliation(s)
- William Byne
- Division of Basic and Laboratory Research, Bronx Veterans Affairs Medical Center, Bronx, NY 10467, United States.
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418
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Küppers E, Gleiser C, Brito V, Wachter B, Pauly T, Hirt B, Grissmer S. AQP4 expression in striatal primary cultures is regulated by dopamine - implications for proliferation of astrocytes. Eur J Neurosci 2008; 28:2173-82. [DOI: 10.1111/j.1460-9568.2008.06531.x] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
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419
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Banasr M, Duman RS. Glial loss in the prefrontal cortex is sufficient to induce depressive-like behaviors. Biol Psychiatry 2008; 64:863-70. [PMID: 18639237 PMCID: PMC2709733 DOI: 10.1016/j.biopsych.2008.06.008] [Citation(s) in RCA: 442] [Impact Index Per Article: 27.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/29/2007] [Revised: 05/16/2008] [Accepted: 06/12/2008] [Indexed: 02/07/2023]
Abstract
BACKGROUND Postmortem studies have repeatedly found decreased density and number of glia in cortical regions, including the prefrontal and cingulate areas, from depressed patients. However, it is unclear whether this glial loss plays a direct role in the expression of depressive symptoms. METHODS To address this question, we characterized the effects of pharmacologic glial ablation in the prefrontal cortex (PFC) of adult rats on behavioral tests known to be affected by stress or antidepressant treatments: sucrose preference test (SPT), novelty suppressed feeding test (NSFT), forced swim test (FST), and two-way active avoidance test (AAT). We established the dose and time course for the actions of an astrocyte specific toxin, L-alpha-aminoadipic acid (L-AAA), and compared the behavioral effects of this gliotoxin with the effects of an excitotoxic (ibotenate) lesion and to the effects of chronic stress. RESULTS The results demonstrate that L-AAA infusions induced anhedonia in SPT, anxiety in NSFT, and helplessness in FST and AAT. These effects of L-AAA were similar to chronic unpredictable stress (CUS)-induced depressive-like behaviors in these tests. However, ibotenate-induced neurotoxic lesion of the PFC had no effect in these behavioral tests. CONCLUSIONS The results demonstrate that glial ablation in the PFC is sufficient to induce depressive-like behaviors similar to chronic stress and support the hypothesis that loss of glia contributes to the core symptoms of depression.
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420
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Michael-Titus AT, Albert M, Michael GJ, Michaelis T, Watanabe T, Frahm J, Pudovkina O, van der Hart MG, Hesselink MB, Fuchs E, Czéh B. SONU20176289, a compound combining partial dopamine D2 receptor agonism with specific serotonin reuptake inhibitor activity, affects neuroplasticity in an animal model for depression. Eur J Pharmacol 2008; 598:43-50. [DOI: 10.1016/j.ejphar.2008.09.006] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2008] [Revised: 08/23/2008] [Accepted: 09/04/2008] [Indexed: 01/11/2023]
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421
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Gosselin RD, Gibney S, O'Malley D, Dinan TG, Cryan JF. Region specific decrease in glial fibrillary acidic protein immunoreactivity in the brain of a rat model of depression. Neuroscience 2008; 159:915-25. [PMID: 19000745 DOI: 10.1016/j.neuroscience.2008.10.018] [Citation(s) in RCA: 116] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2008] [Revised: 10/03/2008] [Accepted: 10/09/2008] [Indexed: 12/11/2022]
Abstract
A growing body of evidence from human postmortem and animal studies suggests that deficits in glial cell (particularly astrocytes) density and function, in limbic regions of the brain contribute to the etiology of depressive disorders. Despite the widespread use of Wistar-Kyoto (WKY) rat strain as a model of depression and stress susceptibility, there is a paucity of data examining whether alterations in brain astrocytic population are present in the model. In the present study, we investigated the expression of the astrocytic markers glial fibrillary acidic protein (GFAP) in various brain regions in WKY rats in comparison to Sprague-Dawley rats. A significant deficit in GFAP-immunoreactive cells was found in the prefrontal cortex region (infralimbic, prelimbic and anterior cingulate cortex), in the basolateral amygdala as well as in the hippocampus (CA3 and dentate gyrus) in WKY rat brain. No statistical difference was found in the other brain regions analyzed (insular cortex, somatosensory cortex, CA1 and callosal white matter). No difference was found in the total density of astrocytes (assessed by s-100beta immunoreactivity), neurons (determined by NeuN expression) or in the total number of cells in the regions of interest. A slight increase in the intensity of s-100beta immunoreactivity was observed. The lower expression of GFAP in WKY rats was further confirmed by Western-blot analysis. These results suggest that specific astrocytic deficits in GFAP expression in corticolimbic circuits may be a general correlate of depressive-like behavior in animal models in addition to human major depression. Moreover, they suggest that glial physiology may become a therapeutic target in depression and other stress-related conditions.
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Affiliation(s)
- R-D Gosselin
- Laboratory of Neurogastroenterology, Alimentary Pharmabiotic Centre, University College Cork, Cork, Ireland
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422
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McIntyre RS, Vagic D, Swartz SA, Soczynska JK, Woldeyohannes HO, Voruganti LP, Konarski JZ. Insulin, insulin-like growth factors and incretins: neural homeostatic regulators and treatment opportunities. CNS Drugs 2008; 22:443-53. [PMID: 18484789 DOI: 10.2165/00023210-200822060-00001] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Mood disorders may be conceptualized as progressive neurodegenerative disorders associated with cognitive decline. Novel treatments capable of preserving and/or enhancing cognitive function represent an area of priority for research in the future. Insulin, insulin-like growth factor (IGF)-1 and incretins may play a critical role in both physiological and pathophysiological processes of the CNS. An emerging paradigm regarding the pathophysiology of mood disorders posits that alterations in biological networks that mediate stress compromise optimal neuronal and glial function. A growing body of evidence indicates that central administration of insulin may enhance cognitive function in both healthy and cognitively impaired individuals. The neuroactive peptides, insulin, IGF-1 and incretins, or agents that facilitate their central effects (e.g. insulin-sensitizing agents), may constitute novel and possibly disease-modifying neurocognitive treatments.
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Affiliation(s)
- Roger S McIntyre
- Department of Psychiatry, University of Toronto, Toronto, Ontario, Canada.
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423
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Ekstrand J, Hellsten J, Tingström A. Environmental enrichment, exercise and corticosterone affect endothelial cell proliferation in adult rat hippocampus and prefrontal cortex. Neurosci Lett 2008; 442:203-7. [DOI: 10.1016/j.neulet.2008.06.085] [Citation(s) in RCA: 90] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2008] [Revised: 06/11/2008] [Accepted: 06/26/2008] [Indexed: 01/29/2023]
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424
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Cunha RA, Ferré S, Vaugeois JM, Chen JF. Potential therapeutic interest of adenosine A2A receptors in psychiatric disorders. Curr Pharm Des 2008; 14:1512-24. [PMID: 18537674 DOI: 10.2174/138161208784480090] [Citation(s) in RCA: 138] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The interest on targeting adenosine A(2A) receptors in the realm of psychiatric diseases first arose based on their tight physical and functional interaction with dopamine D(2) receptors. However, the role of central A(2A) receptors is now viewed as much broader than just controlling D(2) receptor function. Thus, there is currently a major interest in the ability of A(2A) receptors to control synaptic plasticity at glutamatergic synapses. This is due to a combined ability of A(2A) receptors to facilitate the release of glutamate and the activation of NMDA receptors. Therefore, A(2A) receptors are now conceived as a normalizing device promoting adequate adaptive responses in neuronal circuits, a role similar to that fulfilled, in essence, by dopamine. This makes A(2A) receptors particularly attractive targets to manage psychiatric disorders since adenosine may act as go-between glutamate and dopamine, two of the key players in mood processing. Furthermore, A(2A) receptors also control glia function and brain metabolic adaptation, two other emerging mechanisms to understand abnormal processing of mood, and A(2A) receptors are important players in controlling the demise of neurodegeneration, considered an amplificatory loop in psychiatric disorders. Current data only provide an indirect confirmation of this putative role of A(2A) receptors, based on the effects of caffeine (an antagonist of both A(1) and A(2A) receptors) in psychiatric disorders. However, the introduction of A(2A) receptors antagonists in clinics as anti-parkinsonian agents is hoped to bolster our knowledge on the role of A(2A) receptors in mood disorders in the near future.
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Affiliation(s)
- Rodrigo A Cunha
- Center for Neuroscience of Coimbra, Institute of Biochemistry, Faculty of Medicine, University of Coimbra, Portugal.
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425
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Abstract
Methamphetamine is a popular addictive drug whose use is associated with multiple neuropsychiatric adverse events and toxic to the dopaminergic and serotonergic systems of the brain. Methamphetamine-induced neuropathology is associated with increased expression of microglial cells that are thought to participate in either pro-toxic or protective mechanisms in the brain. Although reactive microgliosis has been observed in animal models of methamphetamine neurotoxicity, no study has reported on the status of microglial activation in human methamphetamine abusers. The present study reports on 12 abstinent methamphetamine abusers and 12 age-, gender-, and education-matched control subjects who underwent positron emission tomography using a radiotracer for activated microglia, [(11)C](R)-(1-[2-chlorophenyl]-N-methyl-N-[1-methylpropyl]-3-isoquinoline carboxamide) ([(11)C](R)-PK11195). Compartment analysis was used to estimate quantitative levels of binding potentials of [(11)C](R)-PK11195 in brain regions with dopaminergic and/or serotonergic innervation. The mean levels of [(11)C](R)-PK11195 binding were higher in methamphetamine abusers than those in control subjects in all brain regions (>250% higher; p < 0.01 for all). In addition, the binding levels in the midbrain, striatum, thalamus, and orbitofrontal and insular cortices (p < 0.05) correlated inversely with the duration of methamphetamine abstinence. These results suggest that chronic self-administration of methamphetamine can cause reactive microgliosis in the brains of human methamphetamine abusers, a level of activation that appears to subside over longer periods of abstinence.
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426
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Czéh B, Perez-Cruz C, Fuchs E, Flügge G. Chronic stress-induced cellular changes in the medial prefrontal cortex and their potential clinical implications: Does hemisphere location matter? Behav Brain Res 2008; 190:1-13. [DOI: 10.1016/j.bbr.2008.02.031] [Citation(s) in RCA: 78] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2008] [Accepted: 02/16/2008] [Indexed: 01/10/2023]
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427
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428
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Abstract
Multiple lines of evidence suggest that inflammation and glutamate dysfunction contribute to the pathophysiology of depression. In this review we provide an overview of how these two systems may interact. Excess levels of inflammatory mediators occur in a subgroup of depressed patients. Studies of acute experimental activation of the immune system with endotoxin and of chronic activation during interferon-alpha treatment show that inflammation can cause depression. Peripheral inflammation leads to microglial activation which could interfere with excitatory amino acid metabolism leading to inappropriate glutamate receptor activation. Loss of astroglia, a feature of depression, upsets the balance of anti- and pro-inflammatory mediators and further impairs the removal of excitatory amino acids. Microglia activated by excess inflammation, astroglial loss, and inappropriate glutamate receptor activation ultimately disrupt the delicate balance of neuroprotective versus neurotoxic effects in the brain, potentially leading to depression.
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429
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Targeting the glutamatergic system to develop novel, improved therapeutics for mood disorders. Nat Rev Drug Discov 2008; 7:426-37. [PMID: 18425072 DOI: 10.1038/nrd2462] [Citation(s) in RCA: 649] [Impact Index Per Article: 40.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Mood disorders are common, chronic, recurrent mental illnesses that affect the lives of millions of individuals worldwide. To date, the monoaminergic systems (serotonergic, noradrenergic and dopaminergic) in the brain have received the greatest attention in neurobiological studies of mood disorders, and most therapeutics target these systems. However, there is growing evidence that the glutamatergic system is central to the neurobiology and treatment of these disorders. Here, we review data supporting the involvement of the glutamatergic system in mood-disorder pathophysiology as well as the efficacy of glutamatergic agents in mood disorders. We also discuss exciting new prospects for the development of improved therapeutics for these devastating disorders.
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430
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Balu DT, Hoshaw BA, Malberg JE, Rosenzweig-Lipson S, Schechter LE, Lucki I. Differential regulation of central BDNF protein levels by antidepressant and non-antidepressant drug treatments. Brain Res 2008; 1211:37-43. [PMID: 18433734 DOI: 10.1016/j.brainres.2008.03.023] [Citation(s) in RCA: 142] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2008] [Revised: 03/10/2008] [Accepted: 03/13/2008] [Indexed: 01/18/2023]
Abstract
Antidepressant treatments have been proposed to produce their therapeutic effects, in part, through increasing neurotrophin levels in the brain. The current experiments investigated the effects of acute and chronic treatment with different pharmacologic and somatic antidepressant treatments on protein levels of BDNF in several brain regions associated with depression in the rat. Repeated applications (10 days) of electroconvulsive shock (ECS), but not a single treatment (1 day), produced 40-100% increases of BDNF protein in the hippocampus, frontal cortex, amygdala, and brainstem. Chronic (21 days), but not acute (1 day), treatment with the tricyclic antidepressant (TCA) desipramine (10 mg/kg), the selective serotonin reuptake inhibitor (SSRI) fluoxetine (10 mg/kg), and the monoamine oxidase inhibitor (MAOI) phenelzine (10 mg/kg) increased BDNF protein levels in the frontal cortex (10-30%), but not in the hippocampus, amygdala, olfactory bulb, and brain stem. To determine whether the regulation of BDNF was unique to antidepressant treatments, drugs used to treat schizophrenia and anxiety were also studied. Chronic administration of the typical antipsychotic haloperidol (1 mg/kg) and the atypical antipsychotic clozapine (20 mg/kg) increased BDNF levels by only 8-10% in the frontal cortex. Haloperidol also elevated BDNF levels in the amygdala, while clozapine decreased BDNF in the olfactory bulb. Acute or chronic treatment with the benzodiazepine chlordiazepoxide (10 mg/kg) did not alter BDNF levels. These results suggest that diverse pharmacologic and somatic antidepressant treatments, as well as antipsychotics, increase levels of BDNF protein in the frontal cortex, even though they have different mechanisms of action at neurotransmitter systems.
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Affiliation(s)
- Darrick T Balu
- Department of Pharmacology, University of Pennsylvania, Philadelphia, PA 19104, USA
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431
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Molecular interaction between prion protein and GFAP both in native and recombinant forms in vitro. Med Microbiol Immunol 2007; 197:361-8. [DOI: 10.1007/s00430-007-0071-0] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2007] [Indexed: 11/25/2022]
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432
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Abstract
AIMS The objectives of the present review were to summarise the key findings from the clinical literature regarding the neurobiology of major depressive disorder (MDD) and their implications for maximising treatment outcomes. Several neuroanatomical structures in the prefrontal and limbic areas of the brain are involved in affective regulation. In patients with MDD, alterations in the dynamic patterns of activity among these structures have profound implications for the pathogenesis of this illness. DISCUSSION The present work reviews the evidence for the progressive nature of MDD along with associated changes in neuroanatomical structure and function, especially for the hippocampus. The role of glucocorticoids, inflammatory cytokines and brain-derived growth factors are discussed as mediators of these pathological alterations. From this integrated model, the role of antidepressant therapy in restoring normative processes is examined along with additional treatment guidelines. CONCLUSION Major depressive disorder is an illness with significant neurobiological consequences involving structural, functional and molecular alterations in several areas of the brain. Antidepressant pharmacotherapy is associated with restoration of the underlying physiology. Clinicians are advised to intervene with MDD using an early, comprehensive treatment approach that has remission as the goal.
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Affiliation(s)
- V Maletic
- School of Medicine, University of South Carolina, Greer, SC 29650, USA.
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433
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Kondziella D, Alvestad S, Vaaler A, Sonnewald U. Which clinical and experimental data link temporal lobe epilepsy with depression? J Neurochem 2007; 103:2136-52. [PMID: 17887964 DOI: 10.1111/j.1471-4159.2007.04926.x] [Citation(s) in RCA: 76] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
The association of temporal lobe epilepsy with depression and other neuropsychiatric disorders has been known since the early beginnings of neurology and psychiatry. However, only recently have in vivo and ex vivo techniques such as Positron Emission Tomography, Magnetic Resonance Imaging and Magnetic Resonance Spectroscopy in combination with refined animal models and behavioral tests made it possible to identify an emerging pattern of common pathophysiological mechanisms. We now have growing evidence that in both disorders altered interaction of serotonergic and noradrenergic neurons with glutamatergic systems is associated with abnormal neuronal circuits and hyperexcitability. Neuronal hyperexcitability can possibly evoke seizure activity as well as disturbed emotions. Moreover, decreased synaptic levels of neurotransmitters and high glucocorticoid levels influence intracellular signaling pathways such as cAMP, causing disturbances of brain-derived and other neurotrophic factors. These may be associated with hippocampal atrophy seen on Magnetic Resonance Imaging and memory impairment as well as altered fear processing and transient hypertrophy of the amygdala. Positron Emission Tomography studies additionally suggest hypometabolism of glucose in temporal and frontal lobes. Last, but not least, in temporal lobe epilepsy and depression astrocytes play a role that reaches far beyond their involvement in hippocampal sclerosis and ultimately, therapeutic regulation of glial-neuronal interactions may be a target for future research. All these mechanisms are strongly intertwined and probably bidirectional such that the structural and functional alterations from one disease increase the risk for developing the other. This review provides an integrative update of the most relevant experimental and clinical data on temporal lobe epilepsy and its association with depression.
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Affiliation(s)
- Daniel Kondziella
- Department of Neuroscience, Norwegian University of Science and Technology, Trondheim, Norway.
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