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Herbert J, Lucassen PJ. Depression as a risk factor for Alzheimer's disease: Genes, steroids, cytokines and neurogenesis - What do we need to know? Front Neuroendocrinol 2016; 41:153-71. [PMID: 26746105 DOI: 10.1016/j.yfrne.2015.12.001] [Citation(s) in RCA: 91] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/21/2015] [Revised: 12/23/2015] [Accepted: 12/27/2015] [Indexed: 01/18/2023]
Abstract
Depression (MDD) is prodromal to, and a component of, Alzheimer's disease (AD): it may also be a trigger for incipient AD. MDD is not a unitary disorder, so there may be particular subtypes of early life MDD that pose independent high risks for later AD, though the identification of these subtypes is problematical. There may either be a common pathological event underlying both MDD and AD, or MDD may sensitize the brain to a second event ('hit') that precipitates AD. MDD may also accelerate brain ageing, including altered DNA methylation, increased cortisol but decreasing DHEA and thus the risk for AD. So far, genes predicting AD (e.g. APOEε4) are not risk factors for MDD, and those implicated in MDD (e.g. SLC6A4) are not risks for AD, so a common genetic predisposition looks unlikely. There is as yet no strong indication that an epigenetic event occurs during some forms of MDD that predisposes to later AD, though the evidence is limited. Glucocorticoids (GCs) are disturbed in some cases of MDD and in AD. GCs have marked degenerative actions on the hippocampus, a site of early β-amyloid deposition, and rare genetic variants of GC-regulating enzymes (e.g. 11β-HSD) predispose to AD. GCs also inhibit hippocampal neurogenesis and plasticity, and thus episodic memory, a core symptom of AD. Disordered GCs in MDD may inhibit neurogenesis, but the contribution of diminished neurogenesis to the onset or progression of AD is still debated. GCs and cytokines also reduce BDNF, implicated in both MDD and AD and hippocampal neurogenesis, reinforcing the notion that those cases of MDD with disordered GCs may be a risk for AD. Cytokines, including IL1β, IL6 and TNFα, are increased in the blood in some cases of MDD. They also reduce hippocampal neurogenesis, and increased cytokines are a known risk for later AD. Inflammatory changes occur in both MDD and AD (e.g. raised CRP, TNFα). Both cytokines and GCs can have pro-inflammatory actions in the brain. Inflammation (e.g. microglial activation) may be a common link, but this has not been systematically investigated. We lack substantial, rigorous and comprehensive follow-up studies to better identify possible subtypes of MDD that may represent a major predictor for later AD. This would enable specific interventions during critical episodes of these subtypes of MDD that should reduce this substantial risk.
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Affiliation(s)
- Joe Herbert
- John van Geest Centre for Brain Repair, Department of Clinical Neurosciences, University of Cambridge, UK.
| | - Paul J Lucassen
- Swammerdam Institute for Life Sciences, Center for Neuroscience, University of Amsterdam, The Netherlands
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152
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Ilies R, Aw SS, Lim VK. A Naturalistic Multilevel Framework for Studying Transient and Chronic Effects of Psychosocial Work Stressors on Employee Health and Well-Being. APPLIED PSYCHOLOGY-AN INTERNATIONAL REVIEW-PSYCHOLOGIE APPLIQUEE-REVUE INTERNATIONALE 2016. [DOI: 10.1111/apps.12069] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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153
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Adolescent mice show anxiety- and aggressive-like behavior and the reduction of long-term potentiation in mossy fiber-CA3 synapses after neonatal maternal separation. Neuroscience 2016; 316:221-31. [DOI: 10.1016/j.neuroscience.2015.12.041] [Citation(s) in RCA: 51] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2015] [Revised: 12/05/2015] [Accepted: 12/21/2015] [Indexed: 11/17/2022]
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154
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Biala G, Pekala K, Boguszewska-Czubara A, Michalak A, Kruk-Slomka M, Budzynska B. Behavioral and Biochemical Interaction Between Nicotine and Chronic Unpredictable Mild Stress in Mice. Mol Neurobiol 2016; 54:904-921. [PMID: 26780460 PMCID: PMC5310564 DOI: 10.1007/s12035-016-9701-0] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2015] [Accepted: 01/05/2016] [Indexed: 11/24/2022]
Abstract
Nicotine, the main component of tobacco smoke, exerts influence on mood, and contributes to physical and psychological dependence. Taking into account frequent concomitance of nicotine abuse and stress, we aimed to research behavioral and biochemical effects associated with nicotine administration in combination with chronic unpredictable mild stress (CUMS). Mice were submitted to the procedure of CUMS for 4 weeks, 2 h per day. Our results revealed that CUMS-exposed animals exhibited behavioral alteration like anxiety disorders in the elevated plus maze (EPM) test, the disturbances in memory in the passive avoidance (PA) test and depressive effects in the forced swim test (FST). Moreover, nicotine (0.05–0.5 mg/kg), after an acute or subchronic administration decreased stress-induced depression- and anxiety-like effect as well as memory deficit. Administration of metyrapone (50 mg/kg), a glucocorticosteroid antagonist, alleviated the depressive effect induced by the CUMS. The biochemical experiments showed decreased values of the total antioxidant status (TAS), activities of superoxide dismutase (SOD) and glutathione peroxidase (GPx) with simultaneously increased in malondialdehyde (MDA) concentration in mice submitted to the CUMS. The same effects were observed after an acute and subchronic nicotine administration within all examined brain structures (i.e., hippocampus, cortex, and cerebellum) and in the whole brain in non-stressed and stressed mice confirming pro-oxidative effect of nicotine. Our study contributes to the understanding of behavioral and biochemical mechanisms involved in stress-induced disorders such as depression, anxiety and memory disturbances as well as dual nicotine-stress interactions on the basis of the development of nicotine dependence.
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Affiliation(s)
- G Biala
- Department of Pharmacology and Pharmacodynamics, Medical University of Lublin, Chodzki 4A Street, 20-093, Lublin, Poland.
| | - K Pekala
- Department of Pharmacology and Pharmacodynamics, Medical University of Lublin, Chodzki 4A Street, 20-093, Lublin, Poland
| | - A Boguszewska-Czubara
- Department of Medical Chemistry, Medical University of Lublin, Chodzki 4A Street, 20-093, Lublin, Poland
| | - A Michalak
- Department of Pharmacology and Pharmacodynamics, Medical University of Lublin, Chodzki 4A Street, 20-093, Lublin, Poland
| | - M Kruk-Slomka
- Department of Pharmacology and Pharmacodynamics, Medical University of Lublin, Chodzki 4A Street, 20-093, Lublin, Poland
| | - B Budzynska
- Department of Pharmacology and Pharmacodynamics, Medical University of Lublin, Chodzki 4A Street, 20-093, Lublin, Poland
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155
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Dendritic Spines in Depression: What We Learned from Animal Models. Neural Plast 2016; 2016:8056370. [PMID: 26881133 PMCID: PMC4736982 DOI: 10.1155/2016/8056370] [Citation(s) in RCA: 272] [Impact Index Per Article: 34.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2015] [Accepted: 11/26/2015] [Indexed: 02/07/2023] Open
Abstract
Depression, a severe psychiatric disorder, has been studied for decades, but the underlying mechanisms still remain largely unknown. Depression is closely associated with alterations in dendritic spine morphology and spine density. Therefore, understanding dendritic spines is vital for uncovering the mechanisms underlying depression. Several chronic stress models, including chronic restraint stress (CRS), chronic unpredictable mild stress (CUMS), and chronic social defeat stress (CSDS), have been used to recapitulate depression-like behaviors in rodents and study the underlying mechanisms. In comparison with CRS, CUMS overcomes the stress habituation and has been widely used to model depression-like behaviors. CSDS is one of the most frequently used models for depression, but it is limited to the study of male mice. Generally, chronic stress causes dendritic atrophy and spine loss in the neurons of the hippocampus and prefrontal cortex. Meanwhile, neurons of the amygdala and nucleus accumbens exhibit an increase in spine density. These alterations induced by chronic stress are often accompanied by depression-like behaviors. However, the underlying mechanisms are poorly understood. This review summarizes our current understanding of the chronic stress-induced remodeling of dendritic spines in the hippocampus, prefrontal cortex, orbitofrontal cortex, amygdala, and nucleus accumbens and also discusses the putative underlying mechanisms.
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156
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Hu F, Ge MM, Chen WH. Effects of lead exposure on dendrite and spine development in hippocampal dentate gyrus areas of rats. Synapse 2016; 70:87-97. [DOI: 10.1002/syn.21873] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2015] [Revised: 10/27/2015] [Accepted: 11/02/2015] [Indexed: 11/07/2022]
Affiliation(s)
- Fan Hu
- School of Biotechnology and Food Engineering; Hefei University of Technology; Hefei Anhui 230009 People's Republic of China
| | - Meng-Meng Ge
- School of Biotechnology and Food Engineering; Hefei University of Technology; Hefei Anhui 230009 People's Republic of China
| | - Wei-Heng Chen
- School of Life Sciences; University of Science and Technology of China; Hefei Anhui 230027 People's Republic of China
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157
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Bozelos P, Stefanou SS, Bouloukakis G, Melachrinos C, Poirazi P. REMOD: A Tool for Analyzing and Remodeling the Dendritic Architecture of Neural Cells. Front Neuroanat 2016; 9:156. [PMID: 26778971 PMCID: PMC4701929 DOI: 10.3389/fnana.2015.00156] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2015] [Accepted: 11/16/2015] [Indexed: 01/05/2023] Open
Abstract
Dendritic morphology is a key determinant of how individual neurons acquire a unique signal processing profile. The highly branched dendritic structure that originates from the cell body, explores the surrounding 3D space in a fractal-like manner, until it reaches a certain amount of complexity. Its shape undergoes significant alterations under various physiological or neuropathological conditions. Yet, despite the profound effect that these alterations can have on neuronal function, the causal relationship between the two remains largely elusive. The lack of a systematic approach for remodeling neural cells and their dendritic trees is a key limitation that contributes to this problem. Such causal relationships can be inferred via the use of large-scale neuronal models whereby the anatomical plasticity of neurons is accounted for, in order to enhance their biological relevance and hence their predictive performance. To facilitate this effort, we developed a computational tool named REMOD that allows the structural remodeling of any type of virtual neuron. REMOD is written in Python and can be accessed through a dedicated web interface that guides the user through various options to manipulate selected neuronal morphologies. REMOD can also be used to extract meaningful morphology statistics for one or multiple reconstructions, including features such as sholl analysis, total dendritic length and area, path length to the soma, centrifugal branch order, diameter tapering and more. As such, the tool can be used both for the analysis and/or the remodeling of neuronal morphologies of any type.
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Affiliation(s)
- Panagiotis Bozelos
- Institute of Molecular Biology and Biotechnology (IMBB), Foundation for Research and Technology-Hellas (FORTH)Crete, Greece; Department of Molecular Biology and Genetics, Democritus University of ThraceCrete, Greece
| | - Stefanos S Stefanou
- Institute of Molecular Biology and Biotechnology (IMBB), Foundation for Research and Technology-Hellas (FORTH)Crete, Greece; Department of Biology, University of CreteCrete, Greece
| | - Georgios Bouloukakis
- Institute of Molecular Biology and Biotechnology (IMBB), Foundation for Research and Technology-Hellas (FORTH)Crete, Greece; Computer Science Department, University of CreteCrete, Greece
| | - Constantinos Melachrinos
- Institute of Molecular Biology and Biotechnology (IMBB), Foundation for Research and Technology-Hellas (FORTH) Crete, Greece
| | - Panayiota Poirazi
- Institute of Molecular Biology and Biotechnology (IMBB), Foundation for Research and Technology-Hellas (FORTH) Crete, Greece
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158
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Animal models of major depression and their clinical implications. Prog Neuropsychopharmacol Biol Psychiatry 2016; 64:293-310. [PMID: 25891248 DOI: 10.1016/j.pnpbp.2015.04.004] [Citation(s) in RCA: 242] [Impact Index Per Article: 30.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/21/2015] [Revised: 03/09/2015] [Accepted: 04/12/2015] [Indexed: 12/12/2022]
Abstract
Major depressive disorder is a common, complex, and potentially life-threatening mental disorder that imposes a severe social and economic burden worldwide. Over the years, numerous animal models have been established to elucidate pathophysiology that underlies depression and to test novel antidepressant treatment strategies. Despite these substantial efforts, the animal models available currently are of limited utility for these purposes, probably because none of the models mimics this complex disorder fully. It is presumable that psychiatric illnesses, such as affective disorders, are related to the complexity of the human brain. Here, we summarize the animal models that are used most commonly for depression, and discuss their advantages and limitations. We discuss genetic models, including the recently developed optogenetic tools and the stress models, such as the social stress, chronic mild stress, learned helplessness, and early-life stress paradigms. Moreover, we summarize briefly the olfactory bulbectomy model, as well as models that are based on pharmacological manipulations and disruption of the circadian rhythm. Finally, we highlight common misinterpretations and often-neglected important issues in this field.
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159
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Abstract
Many patients with depression, anxiety disorders, and other psychiatric disorders are treated with combinations of psychodynamic psychotherapy and medication. Whether this is better than monotherapy is an empirical question that requires much more extensive research than is currently available. When medications were first introduced to treat psychiatric illnesses, some psychopharmacologists insisted that it heralded a new area of "biological psychiatry" that would ultimately render psychotherapy obsolete. Psychodynamic theorists and practitioners, on the other hand, argued that psychopharmacology offered only a superficial approach to treatment. Fortunately, these battles are now largely supplanted by the belief that whatever treatment offers the patient the best outcome should be employed, regardless of the therapist's theoretical outlook. This should motivate more extensive study of the value of combination treatment. So far, the few studies that have been done suggest that the combination of psychodynamic psychotherapy and medication may be superior for the treatment of mood and anxiety disorders, but most of these studies have small sample sizes and involve only short-term psychotherapy. An examination of the neuroscience of mood and anxiety disorders and of the mechanism of action of psychodynamic psychotherapy and of antidepressant medication suggests several routes by which the two treatment modalities could be synergistic: stimulation of hippocampal neurogenesis; epigenetic regulation of gene expression; dendritic remodeling; enhanced prefrontal cortical control of limbic system activity; and action at specific neurohormonal and neurotransmitter targets. The evidence for each of these mechanisms is reviewed with an eye toward potential experiments that might be relevant to them.
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160
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Do (epi)genetics impact the brain in functional neurologic disorders? HANDBOOK OF CLINICAL NEUROLOGY 2016; 139:157-165. [DOI: 10.1016/b978-0-12-801772-2.00014-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
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161
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Vega-Rivera NM, Ortiz-López L, Gómez-Sánchez A, Oikawa-Sala J, Estrada-Camarena EM, Ramírez-Rodríguez GB. The neurogenic effects of an enriched environment and its protection against the behavioral consequences of chronic mild stress persistent after enrichment cessation in six-month-old female Balb/C mice. Behav Brain Res 2015; 301:72-83. [PMID: 26721469 DOI: 10.1016/j.bbr.2015.12.028] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2015] [Revised: 12/10/2015] [Accepted: 12/16/2015] [Indexed: 01/02/2023]
Abstract
Because stress may underlie the presence of depressive episodes, strategies to produce protection against or to reverse the effects of stress on neuroplasticity and behavior are relevant. Preclinical studies showed that exposure to stimuli, such as physical activity and environmental enrichment (ENR), produce beneficial effects against stress causing antidepressant-like effects in rodents. Additionally, ENR induces positive effects on neuroplasticity, neurochemistry and behavior at any age of rodents tested. Here, we analyzed whether ENR exposure prevents the development of depressive-like behavior produced by unpredictable, chronic mild stress (CMS) exposure as well as changes in hippocampal neurogenesis in a six-month-old female Balb/C mice, strain that shows low baseline levels of hippocampal neurogenesis. Mice were assigned to one of four groups: (1) normal housing-normal housing (NH-NH), (2) NH-CMS, (3) ENR-NH, or (4) ENR-CMS. The animals were exposed over 46 days to ENR or NH and subsequently to NH or CMS for 4 weeks. ENR induces long-term effects protecting against CMS induction of anhedonia and hopelessness behaviors. Independent of housing conditions, ENR increased the number of proliferative cells (Ki67), and CMS decreased the number of proliferative cells. ENR increased the newborn cells (BrdU) and mature phenotypes of neurons; these effects were not changed by CMS exposure. Similarly, the number of doublecortin-positive cells was not affected by CMS in ENR mice, which showed more cells with complex dendrite arborizations. Our study suggests that ENR induces protection against the effects of CMS on behavior and neuroplasticity in six-month-old Balb/C mice.
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Affiliation(s)
- Nelly Maritza Vega-Rivera
- Laboratory of Neuropsychopharmacology, Division of Neurosciences, National Institute of Psychiatry "Ramón de la Fuente Muñiz", Calz. México-Xochimilco 101, 14370 México, D.F., Mexico
| | - Leonardo Ortiz-López
- Laboratory of Neurogenesis, Division of Clinical Investigations, National Institute of Psychiatry "Ramón de la Fuente Muñiz", Calzada México-Xochimilco 101, 14370 México, D.F., Mexico
| | - Ariadna Gómez-Sánchez
- Laboratory of Neurogenesis, Division of Clinical Investigations, National Institute of Psychiatry "Ramón de la Fuente Muñiz", Calzada México-Xochimilco 101, 14370 México, D.F., Mexico
| | - Julian Oikawa-Sala
- Laboratory of Neurogenesis, Division of Clinical Investigations, National Institute of Psychiatry "Ramón de la Fuente Muñiz", Calzada México-Xochimilco 101, 14370 México, D.F., Mexico
| | - Erika Monserrat Estrada-Camarena
- Laboratory of Neuropsychopharmacology, Division of Neurosciences, National Institute of Psychiatry "Ramón de la Fuente Muñiz", Calz. México-Xochimilco 101, 14370 México, D.F., Mexico.
| | - Gerardo Bernabé Ramírez-Rodríguez
- Laboratory of Neurogenesis, Division of Clinical Investigations, National Institute of Psychiatry "Ramón de la Fuente Muñiz", Calzada México-Xochimilco 101, 14370 México, D.F., Mexico.
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162
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Castro-Gomes V, Bergstrom HC, McGuire JL, Parker CC, Coyner J, Landeira-Fernandez J, Ursano RJ, Palmer AA, Johnson LR. A dendritic organization of lateral amygdala neurons in fear susceptible and resistant mice. Neurobiol Learn Mem 2015; 127:64-71. [PMID: 26642919 DOI: 10.1016/j.nlm.2015.11.010] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2015] [Revised: 11/17/2015] [Accepted: 11/21/2015] [Indexed: 01/05/2023]
Abstract
Subtle differences in neuronal microanatomy may be coded in individuals with genetic susceptibility for neuropsychiatric disorders. Genetic susceptibility is a significant risk factor in the development of anxiety disorders, including post-traumatic stress disorder (PTSD). Pavlovian fear conditioning has been proposed to model key aspects of PTSD. According to this theory, PTSD begins with the formation of a traumatic memory which connects relevant environmental stimuli to significant threats to life. The lateral amygdala (LA) is considered to be a key network hub for the establishment of Pavlovian fear conditioning. Substantial research has also linked the LA to PTSD. Here we used a genetic mouse model of fear susceptibility (F-S) and resistance (F-R) to investigate the dendritic and spine structure of principal neurons located in the LA. F-S and F-R lines were bi-directionally selected based on divergent levels of contextual and cued conditioned freezing in response to fear-evoking footshocks. We examined LA principal neuron dendritic and spine morphology in the offspring of experimentally naive F-S and F-R mice. We found differences in the spatial distribution of dendritic branch points across the length of the dendrite tree, with a significant increase in branch points at more distal locations in the F-S compared with F-R line. These results suggest a genetic predisposition toward differences in fear memory strength associated with a dendritic branch point organization of principal neurons in the LA. These micro-anatomical differences in neuron structure in a genetic mouse model of fear susceptibility and resistance provide important insights into the cellular mechanisms of pathophysiology underlying genetic predispositions to anxiety and PTSD.
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Affiliation(s)
- Vitor Castro-Gomes
- Program in Neuroscience and Department of Psychiatry, Uniformed Services University (USU), School of Medicine, Bethesda, MD 20814, USA; Department of Biosystems Engineering, Federal University of São João del Rei (UFSJ), São João del Rei, MG 36307-352, Brazil
| | - Hadley C Bergstrom
- Program in Neuroscience and Department of Psychiatry, Uniformed Services University (USU), School of Medicine, Bethesda, MD 20814, USA; Department of Psychology and Neuroscience and Behavior Program, Vassar College, Poughkeepsie, NY 12603, USA
| | - Jennifer L McGuire
- Program in Neuroscience and Department of Psychiatry, Uniformed Services University (USU), School of Medicine, Bethesda, MD 20814, USA
| | - Clarissa C Parker
- Department of Psychology and Program in Neuroscience, Middlebury College, Middlebury, VT 05753, USA
| | - Jennifer Coyner
- Program in Neuroscience and Department of Psychiatry, Uniformed Services University (USU), School of Medicine, Bethesda, MD 20814, USA
| | - J Landeira-Fernandez
- Department of Psychology, Pontifical Catholic University of Rio de Janeiro (PUC-Rio), Rio de Janeiro, RJ 22451-900, Brazil
| | - Robert J Ursano
- Program in Neuroscience and Department of Psychiatry, Uniformed Services University (USU), School of Medicine, Bethesda, MD 20814, USA; Center for the Study of Traumatic Stress (CSTS), Bethesda, MD 20814, USA
| | - Abraham A Palmer
- Department of Human Genetics, University of Chicago, IL 60637, USA; Department of Psychiatry and Behavioral Neuroscience, University of Chicago, IL 60637, USA
| | - Luke R Johnson
- Program in Neuroscience and Department of Psychiatry, Uniformed Services University (USU), School of Medicine, Bethesda, MD 20814, USA; Center for the Study of Traumatic Stress (CSTS), Bethesda, MD 20814, USA; School of Psychology and Counseling, Queensland University of Technology (QUT), Brisbane, QLD 4059, Australia; Translational Research Institute (TRI), Brisbane, QLD 4102, Australia.
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163
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Overexpression of Mineralocorticoid Receptors Partially Prevents Chronic Stress-Induced Reductions in Hippocampal Memory and Structural Plasticity. PLoS One 2015; 10:e0142012. [PMID: 26600250 PMCID: PMC4658081 DOI: 10.1371/journal.pone.0142012] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2015] [Accepted: 09/11/2015] [Indexed: 12/02/2022] Open
Abstract
Exposure to chronic stress is a risk factor for cognitive decline and psychopathology in genetically predisposed individuals. Preliminary evidence in humans suggests that mineralocorticoid receptors (MRs) may confer resilience to these stress-related changes. We specifically tested this idea using a well-controlled mouse model for chronic stress in combination with transgenic MR overexpression in the forebrain. Exposure to unpredictable stressors for 21 days in adulthood reduced learning and memory formation in a low arousing hippocampus-dependent contextual learning task, but enhanced stressful contextual fear learning. We found support for a moderating effect of MR background on chronic stress only for contextual memory formation under low arousing conditions. In an attempt to understand potentially contributing factors, we studied structural plasticity. Chronic stress altered dendritic morphology in the hippocampal CA3 area and reduced the total number of doublecortin-positive immature neurons in the infrapyramidal blade of the dentate gyrus. The latter reduction was absent in MR overexpressing mice. We therefore provide partial support for the idea that overexpression of MRs may confer resilience to the effects of chronic stress on hippocampus-dependent function and structural plasticity.
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164
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Daskalakis NP, De Kloet ER, Yehuda R, Malaspina D, Kranz TM. Early Life Stress Effects on Glucocorticoid-BDNF Interplay in the Hippocampus. Front Mol Neurosci 2015; 8:68. [PMID: 26635521 PMCID: PMC4644789 DOI: 10.3389/fnmol.2015.00068] [Citation(s) in RCA: 100] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2015] [Accepted: 10/27/2015] [Indexed: 11/19/2022] Open
Abstract
Early life stress (ELS) is implicated in the etiology of multiple psychiatric disorders. Important biological effects of ELS are manifested in stress-susceptible regions of the hippocampus and are partially mediated by long-term effects on glucocorticoid (GC) and/or neurotrophin signaling pathways. GC-signaling mediates the regulation of stress response to maintain homeostasis, while neurotrophin signaling plays a key role in neuronal outgrowth and is crucial for axonal guidance and synaptic integrity. The neurotrophin and GC-signaling pathways co-exist throughout the central nervous system (CNS), particularly in the hippocampus, which has high expression levels of glucocorticoid-receptors (GR) and mineralocorticoid-receptors (MR) as well as brain-derived neurotrophic factor (BDNF) and its receptor, tropomyosin-related kinase receptor B (TrkB). This review addresses the effects of ELS paradigms on GC- and BDNF-dependent mechanisms and their crosstalk in the hippocampus, including potential implications for the pathogenesis of common stress-related disorders.
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Affiliation(s)
- Nikolaos P Daskalakis
- Traumatic Stress Studies Division and Laboratory of Molecular Neuropsychiatry, Department of Psychiatry, Icahn School of Medicine at Mount Sinai New York, NY, USA ; Mental Health Patient Care Center, James J. Peters Veterans Affairs Medical Center Bronx, NY, USA
| | - Edo Ronald De Kloet
- Department of Medical Pharmacology, Leiden Academic Centre for Drug Research Leiden, Netherlands ; Department of Endocrinology and Metabolism, Leiden University Medical Center, Leiden University Leiden, Netherlands
| | - Rachel Yehuda
- Traumatic Stress Studies Division and Laboratory of Molecular Neuropsychiatry, Department of Psychiatry, Icahn School of Medicine at Mount Sinai New York, NY, USA ; Mental Health Patient Care Center, James J. Peters Veterans Affairs Medical Center Bronx, NY, USA ; Department of Neuroscience, Icahn School of Medicine at Mount Sinai New York, NY, USA
| | - Dolores Malaspina
- Department of Psychiatry, New York University School of Medicine New York, NY, USA
| | - Thorsten M Kranz
- Departments of Cell Biology, Physiology and Neuroscience, and Psychiatry, Skirball Institute of Biomolecular Medicine, New York University New York, NY, USA
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165
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Maiti P, Manna J, Ilavazhagan G, Rossignol J, Dunbar GL. Molecular regulation of dendritic spine dynamics and their potential impact on synaptic plasticity and neurological diseases. Neurosci Biobehav Rev 2015; 59:208-37. [PMID: 26562682 DOI: 10.1016/j.neubiorev.2015.09.020] [Citation(s) in RCA: 83] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2015] [Revised: 08/20/2015] [Accepted: 09/07/2015] [Indexed: 12/12/2022]
Abstract
The structure and dynamics of dendritic spines reflect the strength of synapses, which are severely affected in different brain diseases. Therefore, understanding the ultra-structure, molecular signaling mechanism(s) regulating dendritic spine dynamics is crucial. Although, since last century, dynamics of spine have been explored by several investigators in different neurological diseases, but despite countless efforts, a comprehensive understanding of the fundamental etiology and molecular signaling pathways involved in spine pathology is lacking. The purpose of this review is to provide a contextual framework of our current understanding of the molecular mechanisms of dendritic spine signaling, as well as their potential impact on different neurodegenerative and psychiatric diseases, as a format for highlighting some commonalities in function, as well as providing a format for new insights and perspectives into this critical area of research. Additionally, the potential strategies to restore spine structure-function in different diseases are also pointed out. Overall, these informations should help researchers to design new drugs to restore the structure-function of dendritic spine, a "hot site" of synaptic plasticity.
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Affiliation(s)
- Panchanan Maiti
- Field Neurosciences Institute, St. Mary's of Michigan, Saginaw, MI, USA; Department of Psychology and Neurosciences Program, Central Michigan University, Mt. Pleasant, MI, USA.
| | - Jayeeta Manna
- Department of Physiology, University of Tennessee Health Science Center, Memphis, TN, USA.
| | - G Ilavazhagan
- Hindustan University, Rajiv Gandhi Salai (OMR), Padur, Kelambakam, Chennai, TN, India.
| | - Julien Rossignol
- Department of Psychology and Neurosciences Program, Central Michigan University, Mt. Pleasant, MI, USA; College of Medicine, Central Michigan University, Mt. Pleasant, MI, USA.
| | - Gary L Dunbar
- Field Neurosciences Institute, St. Mary's of Michigan, Saginaw, MI, USA; Department of Psychology and Neurosciences Program, Central Michigan University, Mt. Pleasant, MI, USA.
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166
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Farrell MR, Gruene TM, Shansky RM. The influence of stress and gonadal hormones on neuronal structure and function. Horm Behav 2015; 76:118-24. [PMID: 25819727 PMCID: PMC4583315 DOI: 10.1016/j.yhbeh.2015.03.003] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/16/2014] [Revised: 03/11/2015] [Accepted: 03/19/2015] [Indexed: 11/27/2022]
Abstract
This article is part of a Special Issue "SBN 2014". The brain is highly plastic, allowing us to adapt and respond to environmental and physiological challenges and experiences. In this review, we discuss the relationships among alterations in dendritic arborization, spine morphology, and behavior due to stress exposure, endogenous hormone fluctuation, or exogenous hormonal manipulation. Very few studies investigate structure-function associations directly in the same cohort of animals, and there are notable inconsistencies in evidence of structure-function relationships in the prefrontal cortex and hippocampus. Moreover, little work has been done to probe the causal relationship between dendritic morphology and neuronal excitability, leaving only speculation about the adaptive versus maladaptive nature of experience-dependent dendritic remodeling. We propose that future studies combine electrophysiology with a circuit-level approach to better understand how dendritic structure contributes to neuronal functional properties and behavioral outcomes.
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Affiliation(s)
| | - Tina M Gruene
- Department of Psychology, Northeastern University, USA
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167
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Parésys L, Hoffmann K, Froger N, Bianchi M, Villey I, Baulieu EE, Fuchs E. Effects of the Synthetic Neurosteroid: 3β-Methoxypregnenolone (MAP4343) on Behavioral and Physiological Alterations Provoked by Chronic Psychosocial Stress in Tree Shrews. Int J Neuropsychopharmacol 2015; 19:pyv119. [PMID: 26476437 PMCID: PMC4851265 DOI: 10.1093/ijnp/pyv119] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/22/2015] [Accepted: 10/14/2015] [Indexed: 02/04/2023] Open
Abstract
BACKGROUND Most currently available active antidepressant drugs are selective serotonin/noradrenaline reuptake inhibitors. However, as their clinical efficacy is not immediate, long-term administration is often accompanied by substantial side effects, and numerous patients remain non- or partial responders. We have recently found that the synthetic neurosteroid derivative 3β-methoxypregnenolone, which binds to the microtubule-associated protein-2, can provide a novel therapeutic approach in experimental model of depressive disorders in rats. To further validate the antidepressant-like efficacy of 3β-methoxypregnenolone, we investigated effects of a longer treatment (4-week oral administration; 50mg/kg/d) in a nonrodent species, the tree shrew, exposed to psychosocial stress that elicits close-to-human alterations observed in patients with depressive disorders. METHODS During the experimental period, physiological parameters were registered, including core body temperature and electroencephalogram, while animals were videotaped to analyze their avoidance behavior. Morning urine samples were collected for measurements of cortisol and noradrenaline levels. RESULTS We found that treatment with 3β-methoxypregnenolone abolished stress-triggered avoidance behavior and prevented hormone hypersecretion, hypothermia, and sleep disturbances, further suggesting its antidepressant-like efficacy. Comparative treatment with fluoxetine also prevented some of the physiological alterations, while the hypersecretion of cortisol and sleep disturbances were not or partially restored by fluoxetine, suggesting a better efficacy of 3β-methoxypregnenolone. Alpha-tubulin isoforms were measured in hippocampi: we found that 3β-methoxypregnenolone reversed the specific decrease in acetylation of α-tubulin induced by psychosocial stress, while it did not modify the psychosocial stress-elicited reduction of tyrosinated α-tubulin. CONCLUSIONS Taken together, these data strongly suggest a potent antidepressant-like effect of 3β-methoxypregnenolone on translational parameters.
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Affiliation(s)
| | | | - Nicolas Froger
- MAPREG SAS, Le Kremlin-Bicêtre, France (Drs Parésys, Froger, Bianchi, Villey, and Baulieu); German Primate Center, Göttingen, Germany (Drs Hoffmann and Fuchs).
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168
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Abstract
Abstract. For many years, Tupaia (family Tupaiidae), most commonly known as tree shrews, have been studied almost exclusively by zoologists resulting in a controversial debate on their taxonomic status among mammals. Today, tree shrews are placed in the order Scandentia; they are valuable, widely accepted and increasingly used model animals as an alternative to rodents and non-human primates in biomedical research. After a brief description on how tree shrews entered science and their taxonomic odyssey, the present article describes the history of the tree shrew (Tupaia belangeri) colony at the German Primate Center and selected aspects of our work with special emphasis on the psychosocial stress model in these animals.
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169
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Xu Y, Cheng X, Cui X, Wang T, Liu G, Yang R, Wang J, Bo X, Wang S, Zhou W, Zhang Y. Effects of 5-h multimodal stress on the molecules and pathways involved in dendritic morphology and cognitive function. Neurobiol Learn Mem 2015; 123:225-38. [DOI: 10.1016/j.nlm.2015.06.011] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2015] [Revised: 06/17/2015] [Accepted: 06/23/2015] [Indexed: 11/25/2022]
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170
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Duman CH, Duman RS. Spine synapse remodeling in the pathophysiology and treatment of depression. Neurosci Lett 2015; 601:20-9. [PMID: 25582786 PMCID: PMC4497940 DOI: 10.1016/j.neulet.2015.01.022] [Citation(s) in RCA: 183] [Impact Index Per Article: 20.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2014] [Revised: 01/07/2015] [Accepted: 01/08/2015] [Indexed: 12/21/2022]
Abstract
Clinical brain imaging and postmortem studies provide evidence of structural and functional abnormalities of key limbic and cortical structures in depressed patients, suggesting that spine synapse connectivity is altered in depression. Characterization of the cellular determinants underlying these changes in patients are limited, but studies in rodent models demonstrate alterations of dendrite complexity and spine density and function that could contribute to the morphological and functional alterations observed in humans. Rodent studies demonstrate region specific effects in chronic stress models of depression, including reductions in dendrite complexity and spine density in the hippocampus and prefrontal cortex (PFC) but increases in the basolateral amygdala and nucleus accumbens. Alterations of spine synapse connectivity in these regions are thought to contribute to the behavioral symptoms of depression, including disruption of cognition, mood, emotion, motivation, and reward. Studies of the mechanisms underlying these effects demonstrate a role for altered brain derived neurotrophic factor (BDNF) signaling that regulates synaptic protein synthesis. In contrast, there is evidence that chronic antidepressant treatment can block or reverse the spine synapse alterations caused by stress. Notably, the new fast acting antidepressant ketamine, which produces rapid therapeutic actions in treatment resistant MDD patients, rapidly increases spine synapse number in the PFC of rodents and reverses the effects of chronic stress. The rapid synaptic and behavioral actions of ketamine occur via increased BDNF regulation of synaptic protein synthesis. Together these studies provide evidence for a neurotophic and synaptogenic hypothesis of depression and treatment response and indicate that spine synapse connectivity in key cortical and limbic brain regions is critical for control of mood and emotion.
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Affiliation(s)
- Catharine H Duman
- Laboratory of Molecular Psychiatry, Department of Psychiatry, Yale University School of Medicine, 34 Park Street, New Haven, CT 06508, USA
| | - Ronald S Duman
- Laboratory of Molecular Psychiatry, Department of Psychiatry, Yale University School of Medicine, 34 Park Street, New Haven, CT 06508, USA.
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171
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Nashed MG, Seidlitz EP, Frey BN, Singh G. Depressive-like behaviours and decreased dendritic branching in the medial prefrontal cortex of mice with tumors: A novel validated model of cancer-induced depression. Behav Brain Res 2015. [PMID: 26222786 DOI: 10.1016/j.bbr.2015.07.040] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Depression is commonly comorbid in cancer patients and has detrimental effects on disease progression. Evidence suggests that biological mechanisms may induce the onset of cancer-induced depression (CID). The present investigation aims to establish a validated preclinical animal model of CID. Female BALB/c mice were allocated to four groups: control (n=12), chronic oral exposure to corticosterone (CORT) (n=12), CORT exposure followed by chronic low dose fluoxetine (FLX) treatment (n=12), and subcutaneous inoculation of 4T1 mammary carcinoma cells (n=13). Anhedonia was evaluated using the sucrose preference test (SPT), and behavioural despair was evaluated using the forced swim test (FST) and tail suspension test (TST). Sholl analyses were used to examine the dendritic morphology of Golgi-Cox impregnated neurons from the medial prefrontal cortex (mPFC). CORT exposure and tumor burden were both associated with decreased sucrose preference, increased FST immobility, and decreased basilar and apical dendritic branching of neurons in the mPFC. CORT-induced behavioural and dendritic morphological changes were reversible by FLX. No differences in TST immobility were observed between groups. On the secondary TST outcome measure, CORT exposure and tumor burden were associated with a trend towards decreased power of movement. CORT exposure induced a positive control model of a depressive-like state, with FLX treatment confirming the predictive validity of the model. This verified the sensitivity of behavioural and histological tests, which were used to assess the CID model. The induction of a depressive-like state in this model represents the first successfully validated animal model of CID.
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Affiliation(s)
- Mina G Nashed
- Department of Pathology & Molecular Medicine, McMaster University, Hamilton, ON L8N 3Z5, Canada; Michael G. DeGroote Institute for Pain Research and Care, McMaster University, Hamilton, ON L8N 3Z5, Canada
| | - Eric P Seidlitz
- Department of Pathology & Molecular Medicine, McMaster University, Hamilton, ON L8N 3Z5, Canada; Michael G. DeGroote Institute for Pain Research and Care, McMaster University, Hamilton, ON L8N 3Z5, Canada
| | - Benicio N Frey
- Department of Psychiatry and Behavioural Neurosciences, McMaster University, Hamilton, ON L8N 3Z5, Canada; Mood Disorders Program and Women's Health Concerns Clinic, St. Joseph's Healthcare Hamilton, ON L8P 3P6, Canada
| | - Gurmit Singh
- Department of Pathology & Molecular Medicine, McMaster University, Hamilton, ON L8N 3Z5, Canada; Michael G. DeGroote Institute for Pain Research and Care, McMaster University, Hamilton, ON L8N 3Z5, Canada.
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172
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O'Doherty DCM, Chitty KM, Saddiqui S, Bennett MR, Lagopoulos J. A systematic review and meta-analysis of magnetic resonance imaging measurement of structural volumes in posttraumatic stress disorder. Psychiatry Res 2015; 232:1-33. [PMID: 25735885 DOI: 10.1016/j.pscychresns.2015.01.002] [Citation(s) in RCA: 232] [Impact Index Per Article: 25.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/10/2014] [Revised: 11/15/2014] [Accepted: 01/08/2015] [Indexed: 12/15/2022]
Abstract
Posttraumatic stress disorder (PTSD) is a debilitating condition associated with mild to moderate cognitive impairment and with a prevalence rate of up to 22% in veterans. This systematic review and quantitative meta-analysis explore volumetric differences of three key structural brain regions (hippocampus, amygdala and anterior cingulate cortex (ACC)), all of which have been implicated in dysfunction of both salience network (SN) and default mode network (DMN) in PTSD sufferers. A literature search was conducted in Embase, Medline, PubMed and PsycINFO in May 2013. Fifty-nine volumetric analyses from 44 articles were examined and included (36 hippocampus, 14 amygdala and nine ACC) with n=846 PTSD participants, n=520 healthy controls (HCs) and n=624 traumatised controls (TCs). Nine statistical tests were performed for each of the three regions of interest (ROIs), measuring volume differences in PTSD subjects, healthy and traumatised controls. Hippocampal volume was reduced in subjects with PTSD, with a greater reduction in the left hippocampus. A medium effect size reduction was found in bilateral amygdala volume when compared with findings in healthy controls; however, no significant differences in amygdala volume between PTSD subjects and trauma-exposed controls were found. Significant volume reductions were found bilaterally in the ACC. While often well matched with their respective control groups, the samples of PTSD subjects composed from the source studies used in the meta-analyses are limited in their homogeneity. The current findings of reduced hippocampal volume in subjects with PTSD are consistent with the existing literature. Amygdala volumes did not show significant reductions in PTSD subjects when compared with volumes in trauma-exposed controls-congruous with reported symptoms of hypervigilance and increased propensity in acquisition of conditioned fear memories-but a significant reduction was found in the combined left and right hemisphere volume analysis when compared with healthy controls. Bilateral volume reductions in the ACC may underpin the attentional deficits and inabilities to modulate emotions that are characteristically associated with PTSD patients.
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Affiliation(s)
- Daniel C M O'Doherty
- Brain and Mind Research Institute, University of Sydney, 100 Mallett Street, Camperdown, NSW 2050, Australia.
| | - Kate M Chitty
- Brain and Mind Research Institute, University of Sydney, 100 Mallett Street, Camperdown, NSW 2050, Australia.
| | - Sonia Saddiqui
- Faculty of Human Sciences, Macquarie University, Sydney, Australia.
| | - Maxwell R Bennett
- Brain and Mind Research Institute, University of Sydney, 100 Mallett Street, Camperdown, NSW 2050, Australia.
| | - Jim Lagopoulos
- Brain and Mind Research Institute, University of Sydney, 100 Mallett Street, Camperdown, NSW 2050, Australia.
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173
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Resistance to antidepressant drugs: the case for a more predisposition-based and less hippocampocentric research paradigm. Behav Pharmacol 2015; 25:352-71. [PMID: 25083567 DOI: 10.1097/fbp.0000000000000066] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The first half of this paper briefly reviews the evidence that (i) stress precipitates depression by damaging the hippocampus, leading to changes in the activity of a distributed neural system involving, inter alia, the amygdala, the ventromedial and dorsolateral prefrontal cortex, the lateral habenula and ascending monoamine pathways, and (ii) antidepressants work by repairing the damaged hippocampus, thus restoring the normal balance of activity within that circuitry. In the second half of the paper we review the evidence that heightened vulnerability to depression, either because of a clinical history of depression or because of the presence of genetic, personality or developmental risk factors, also confers resistance to antidepressant drug treatment. Thus, although antidepressants provide an efficient means of reversing the neurotoxic effects of stress, they are much less effective in conditions where vulnerability to depression is elevated and the role of stress in precipitating depression is correspondingly lower. Consequently, the issue of vulnerability should feature much more prominently in antidepressant research. Most of the current animal models of depression are based on the induction of a depressive-like phenotype by stress, and pay scant attention to vulnerability. As antidepressants are relatively ineffective in vulnerable individuals, this in turn implies a need for the development of different clinical and preclinical methodologies, and a shift of focus away from the current preoccupation with the hippocampus as a target for antidepressant action in vulnerable patients.
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174
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Prenatal exposure to bisphenol A impacts neuronal morphology in the hippocampal CA1 region in developing and aged mice. Arch Toxicol 2015; 90:691-700. [PMID: 25804199 PMCID: PMC4754327 DOI: 10.1007/s00204-015-1485-x] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2014] [Accepted: 02/12/2015] [Indexed: 01/22/2023]
Abstract
Bisphenol A (BPA), a widely used raw component of polycarbonate plastics and epoxy resins, has been reported to induce developmental neurotoxicity in offspring born to dams exposed to low doses of BPA; however, the toxicity mechanism remains elusive. To study the effects of in utero BPA exposure on neuronal morphology, we studied spine density and dendritic growth in the hippocampal CA1 of aged mice and developing mice prenatally exposed to low doses of BPA. Pregnant mice were orally administered BPA at a low dose of 0, 40, or 400 μg/kg body weight/day on gestational days 8.5–17.5/18.5. Mouse progenies were euthanized at 3 weeks or 14 months, and their brains were analyzed for dendritic arborization of GFP-expressing neurons or spine densities of Golgi-stained neurons in the hippocampal CA1. Regardless of the dose, in utero BPA exposure reduced spine densities in the hippocampal CA1 of the 14-month-old mice. In the developing brain from the 3-week-old mice born to dams exposed to BPA at a dose of 400 μg/kg body weight/day, overall length and branching number of basal dendrites but not apical dendrites were decreased. In utero low doses of BPA exposure disrupts hippocampal CA1 neuronal morphology during development, and this disruption is believed to persist in adulthood.
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175
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Chronic stress enhanced fear memories are associated with increased amygdala zif268 mRNA expression and are resistant to reconsolidation. Neurobiol Learn Mem 2015; 120:61-8. [PMID: 25732249 DOI: 10.1016/j.nlm.2015.02.004] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2014] [Revised: 01/23/2015] [Accepted: 02/03/2015] [Indexed: 01/25/2023]
Abstract
The chronically stressed brain may present a vulnerability to develop maladaptive fear-related behaviors in response to a traumatic event. In rodents, chronic stress leads to amygdala hyperresponsivity and dendritic hypertrophy and produces a post traumatic stress disorder (PTSD)-like phenotype that includes exaggerated fear learning following Pavlovian fear conditioning and resistance to extinction. It is unknown whether chronic stress-induced enhanced fear memories are vulnerable to disruption via reconsolidation blockade, as a novel therapeutic approach for attenuating exaggerated fear memories. We used a chronic stress procedure in a rat model (wire mesh restraint for 6h/d/21d) to create a vulnerable brain that leads to a PTSD-like phenotype. We then examined freezing behavior during acquisition, reactivation and after post-reactivation rapamycin administration (i.p., 40mg/kg) in a Pavlovian fear conditioning paradigm to determine its effects on reconsolidation as well as the subsequent functional activation of limbic structures using zif268 mRNA. Chronic stress increased amygdala zif268 mRNA during fear memory retrieval at reactivation. Moreover, these enhanced fear memories were unaffected by post reactivation rapamycin to disrupt long-term fear memory. Also, post-reactivation long term memory processing was also associated with increased amygdala (LA and BA), and decreased hippocampal CA1 zif268 mRNA expression. These results suggest potential challenges for reconsolidation blockade as an effective approach in treating exaggerated fear memories, as in PTSD. Our findings also support chronic stress manipulations combined with fear conditioning as a useful preclinical approach to study a PTSD-like phenotype.
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176
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Wohleb ES, McKim DB, Sheridan JF, Godbout JP. Monocyte trafficking to the brain with stress and inflammation: a novel axis of immune-to-brain communication that influences mood and behavior. Front Neurosci 2015; 8:447. [PMID: 25653581 PMCID: PMC4300916 DOI: 10.3389/fnins.2014.00447] [Citation(s) in RCA: 231] [Impact Index Per Article: 25.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2014] [Accepted: 12/19/2014] [Indexed: 12/13/2022] Open
Abstract
HIGHLIGHTSPsychological stress activates neuroendocrine pathways that alter immune responses.Stress-induced alterations in microglia phenotype and monocyte priming leads to aberrant peripheral and central inflammation.Elevated pro-inflammatory cytokine levels caused by microglia activation and recruitment of monocytes to the brain contribute to development and persistent anxiety-like behavior.Mechanisms that mediate interactions between microglia, endothelial cells, and macrophages and how these contribute to changes in behavior are discussed.Sensitization of microglia and re-distribution of primed monocytes are implicated in re-establishment of anxiety-like behavior. Psychological stress causes physiological, immunological, and behavioral alterations in humans and rodents that can be maladaptive and negatively affect quality of life. Several lines of evidence indicate that psychological stress disrupts key functional interactions between the immune system and brain that ultimately affects mood and behavior. For example, activation of microglia, the resident innate immune cells of the brain, has been implicated as a key regulator of mood and behavior in the context of prolonged exposure to psychological stress. Emerging evidence implicates a novel neuroimmune circuit involving microglia activation and sympathetic outflow to the peripheral immune system that further reinforces stress-related behaviors by facilitating the recruitment of inflammatory monocytes to the brain. Evidence from various rodent models, including repeated social defeat (RSD), revealed that trafficking of monocytes to the brain promoted the establishment of anxiety-like behaviors following prolonged stress exposure. In addition, new evidence implicates monocyte trafficking from the spleen to the brain as key regulator of recurring anxiety following exposure to prolonged stress. The purpose of this review is to discuss mechanisms that cause stress-induced monocyte re-distribution in the brain and how dynamic interactions between microglia, endothelial cells, and brain macrophages lead to maladaptive behavioral responses.
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Affiliation(s)
- Eric S Wohleb
- Department of Psychiatry, Yale University School of Medicine New Haven, CT, USA
| | - Daniel B McKim
- Division of Biosciences, The Ohio State University College of Dentistry Columbus, OH, USA ; Department of Neuroscience, The Ohio State University College of Medicine Columbus, OH, USA
| | - John F Sheridan
- Division of Biosciences, The Ohio State University College of Dentistry Columbus, OH, USA ; Institute for Behavioral Medicine Research, The Ohio State University College of Medicine Columbus, OH, USA ; Center for Brain and Spinal Cord Repair, The Ohio State University College of Medicine Columbus, OH, USA
| | - Jonathan P Godbout
- Department of Neuroscience, The Ohio State University College of Medicine Columbus, OH, USA ; Institute for Behavioral Medicine Research, The Ohio State University College of Medicine Columbus, OH, USA ; Center for Brain and Spinal Cord Repair, The Ohio State University College of Medicine Columbus, OH, USA
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177
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Suri D, Vaidya VA. The adaptive and maladaptive continuum of stress responses – a hippocampal perspective. Rev Neurosci 2015; 26:415-42. [DOI: 10.1515/revneuro-2014-0083] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2014] [Accepted: 02/22/2015] [Indexed: 12/21/2022]
Abstract
AbstractExposure to stressors elicits a spectrum of responses that span from potentially adaptive to maladaptive consequences at the structural, cellular and physiological level. These responses are particularly pronounced in the hippocampus where they also appear to influence hippocampal-dependent cognitive function and emotionality. The factors that influence the nature of stress-evoked consequences include the chronicity, severity, predictability and controllability of the stressors. In addition to adult-onset stress, early life stress also elicits a wide range of structural and functional responses, which often exhibit life-long persistence. However, the outcome of early stress exposure is often contingent on the environment experienced in adulthood, and could either aid in stress coping or could serve to enhance susceptibility to the negative consequences of adult stress. This review comprehensively examines the consequences of adult and early life stressors on the hippocampus, with a focus on their effects on neurogenesis, neuronal survival, structural and synaptic plasticity and hippocampal-dependent behaviors. Further, we discuss potential factors that may tip stress-evoked consequences from being potentially adaptive to largely maladaptive.
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178
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Hall BS, Moda RN, Liston C. Glucocorticoid Mechanisms of Functional Connectivity Changes in Stress-Related Neuropsychiatric Disorders. Neurobiol Stress 2015; 1:174-183. [PMID: 25729760 PMCID: PMC4340078 DOI: 10.1016/j.ynstr.2014.10.008] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Stress—especially chronic, uncontrollable stress—is an important risk factor for many neuropsychiatric disorders. The underlying mechanisms are complex and multifactorial, but they involve correlated changes in structural and functional measures of neuronal connectivity within cortical microcircuits and across neuroanatomically distributed brain networks. Here, we review evidence from animal models and human neuroimaging studies implicating stress-associated changes in functional connectivity in the pathogenesis of PTSD, depression, and other neuropsychiatric conditions. Changes in fMRI measures of corticocortical connectivity across distributed networks may be caused by specific structural alterations that have been observed in the prefrontal cortex, hippocampus, and other vulnerable brain regions. These effects are mediated in part by glucocorticoids, which are released from the adrenal gland in response to a stressor and also oscillate in synchrony with diurnal rhythms. Recent work indicates that circadian glucocorticoid oscillations act to balance synapse formation and pruning after learning and during development, and chronic stress disrupts this balance. We conclude by considering how disrupted glucocorticoid oscillations may contribute to the pathophysiology of depression and PTSD in vulnerable individuals, and how circadian rhythm disturbances may affect non-psychiatric populations, including frequent travelers, shift workers, and patients undergoing treatment for autoimmune disorders.
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Affiliation(s)
- Baila S Hall
- Brain and Mind Research Institute and Program in Neuroscience, Weill Cornell Medical College, 413 East 69 Street, Box 240, New York, NY 10021
| | - Rachel N Moda
- Brain and Mind Research Institute and Program in Neuroscience, Weill Cornell Medical College, 413 East 69 Street, Box 240, New York, NY 10021
| | - Conor Liston
- Brain and Mind Research Institute and Program in Neuroscience, Weill Cornell Medical College, 413 East 69 Street, Box 240, New York, NY 10021 ; Sackler Institute for Developmental Psychobiology, Weill Cornell Medical College, 413 East 69 Street, Box 240, New York, NY 10021 ; Department of Psychiatry, Weill Cornell Medical College, 413 East 69 Street, Box 240, New York, NY 10021
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179
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Rico AM, Mendoza AL, Durán DAB, Torres HDLL, Mendoza GA, Gómez ABS. The effects of chronic restraint on the morphology of ventral CA1 neurons in female Long Evans rats. Stress 2015; 18:67-75. [PMID: 25287136 DOI: 10.3109/10253890.2014.974029] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Women are more likely than men to develop psychopathology as a result of stress, but there is little research regarding the effects of a stressful condition and its treatment in female non-human animals, perhaps because of inherent hormonal activity. Recent studies have demonstrated that there are structural and functional differences between the dorsal and ventral hippocampus, but the effects of stress on the morphology of CA1 and CA3 neurons have been studied primarily in the dorsal hippocampus. This study assessed the effects of stress induced by restricted movement on the morphology of ventral hippocampal CA1 neurons in male and female rats. Male and female Long Evans (LE) rats were subjected to restraint stress for 6 h every day for 25 days. One group of rats was used to study the dendritic morphology of CA1 ventral hippocampal neurons using the Golgi-Cox stain. A second group of rats was used to analyze learning and memory using the Morris water maze. Stressed female rats exhibited a decrease in the density of basilar dendritic spines, an increase in the number of apical dendritic intersections and deficits in spatial memory. There were no apparent effects of stress on male rats. Our data support previous findings of a dimorphic response to chronic stress and indicate that the ventral hippocampus is not particularly susceptible to the effects of stress.
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Affiliation(s)
- Alexander Morales Rico
- Laboratorio de Neurofisiología Experimental, Escuela de Biología, Universidad Autónoma de Puebla , Puebla , Mexico
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180
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Beery AK, Kaufer D. Stress, social behavior, and resilience: insights from rodents. Neurobiol Stress 2015; 1:116-127. [PMID: 25562050 PMCID: PMC4281833 DOI: 10.1016/j.ynstr.2014.10.004] [Citation(s) in RCA: 239] [Impact Index Per Article: 26.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2014] [Accepted: 10/24/2014] [Indexed: 11/20/2022] Open
Abstract
The neurobiology of stress and the neurobiology of social behavior are deeply intertwined. The social environment interacts with stress on almost every front: social interactions can be potent stressors; they can buffer the response to an external stressor; and social behavior often changes in response to stressful life experience. This review explores mechanistic and behavioral links between stress, anxiety, resilience, and social behavior in rodents, with particular attention to different social contexts. We consider variation between several different rodent species and make connections to research on humans and non-human primates.
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Affiliation(s)
- Annaliese K. Beery
- Department of Psychology, Department of Biology, Neuroscience Program, Smith College, Northampton, MA, USA
| | - Daniela Kaufer
- Department of Integrative Biology, Helen Wills Neuroscience Institute, University of California, Berkeley, CA, USA
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181
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Abstract
Objectives:To examine the ultrastructural effects of maternal deprivation during developmental periods of limbi-chypothalamo-pituitary-adrenal system on hippocampal dendritic structures in adult rats.Methods:The experiments were carried out with male and female wistar rats in our department. The rats were mated and, after birth, the pups were divided into four groups. The first group (control group) pups remained undisturbed with their dam until postweaning day 22. Maternal deprived groups were separated from their dams for 24 hours at postnatal day 4, 9 and 18. The subjects were provided with food and water ad libitum until 3-months-of-age. At the third month, the rats were transcardially perfused, samples were taken from CA1 and CA3 regions of the hippocampus. Tissues were prepared for electron microscopy.Results:When the data were analyzed, there were no differences between male and female rats in both ultrastructure and semiquantitative analysis of axodendritic synapses. The ultrastructure of Group 1 was seen as normal while in the second Group some neurons nuclear envelope made deep invagination into the nucleus. Additionally, axodendritic synapses were found normal. In Group 3, micrographs and axodendritic synapses were showed normal structure. However, in Group 4 in some neurons invaginations were seen similar to Group 2. Axodendritic synapses were found to be normal.Conclusion:These experiments establish that MD in rats produces slight ultrastructural changes and decreases the number of synapses in CA1 and CA3 subregions of the hippocampus.
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182
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Czéh B, Varga ZKK, Henningsen K, Kovács GL, Miseta A, Wiborg O. Chronic stress reduces the number of GABAergic interneurons in the adult rat hippocampus, dorsal-ventral and region-specific differences. Hippocampus 2014; 25:393-405. [PMID: 25331166 DOI: 10.1002/hipo.22382] [Citation(s) in RCA: 104] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/09/2014] [Indexed: 11/05/2022]
Abstract
Major depressive disorder is a common and complex mental disorder with unknown etiology. GABAergic dysfunction is likely to contribute to the pathophysiology since disrupted GABAergic systems are well documented in depressed patients. Here we studied structural changes in the hippocampal GABAergic network using the chronic mild stress (CMS) model, as one of the best validated animal models for depression. Rats were subjected to 9 weeks of daily stress and behaviorally characterized using the sucrose consumption test into anhedonic and resilient animals based on their response to stress. Different subtypes of GABAergic interneurons were visualized by immunohistochemistry using antibodies for parvalbumin (PV), calretinin (CR), calbindin (CB), cholecystokinin (CCK), somatostatin (SOM), and neuropeptide Y (NPY). We used an unbiased quantification method to systematically count labeled cells in different subareas of the dorsal and ventral hippocampus. Chronic stress reduced the number of specific interneurons in distinct hippocampal subregions significantly. PV+ and CR+ neurons were reduced in all dorsal subareas, whereas in the ventral part only the CA1 was affected. Stress had the most pronounced effect on the NPY+ and SOM+ cells and reduced their number in almost all dorsal and ventral subareas. Stress had no effect on the CCK+ and CB+ interneurons. In most cases the effect of stress was irrespective to the behavioral phenotype. However, in a few specific areas the number of SOM+, NPY+, and CR+ neurons were significantly reduced in anhedonic animals compared to the resilient group. Overall, these data clearly demonstrate that chronic stress affects the structural integrity of specific GABAergic neuronal subpopulations and this should also affect the functioning of these hippocampal GABAergic networks.
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Affiliation(s)
- Boldizsár Czéh
- Institute of Laboratory Medicine, Faculty of Medicine, University of Pécs, 7624, Pécs, Hungary; Structural Neurobiology Research Group, Szentágothai János Research Center, University of Pécs, 7624, Pécs, Hungary; Translational Neuropsychiatry Unit, Department of Clinical Medicine, Aarhus University, 8240, Risskov, Denmark
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183
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Henckens MJAG, van der Marel K, van der Toorn A, Pillai AG, Fernández G, Dijkhuizen RM, Joëls M. Stress-induced alterations in large-scale functional networks of the rodent brain. Neuroimage 2014; 105:312-22. [PMID: 25462693 DOI: 10.1016/j.neuroimage.2014.10.037] [Citation(s) in RCA: 83] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2014] [Revised: 09/20/2014] [Accepted: 10/08/2014] [Indexed: 02/07/2023] Open
Abstract
Stress-related psychopathology is associated with altered functioning of large-scale brain networks. Animal research into chronic stress, one of the most prominent environmental risk factors for development of psychopathology, has revealed molecular and cellular mechanisms potentially contributing to human mental disease. However, so far, these studies have not addressed the system-level changes in extended brain networks, thought to critically contribute to mental disorders. We here tested the effects of chronic stress exposure (10 days immobilization) on the structural integrity and functional connectivity patterns in the brain, using high-resolution structural MRI, diffusion kurtosis imaging, and resting-state functional MRI, while confirming the expected changes in neuronal dendritic morphology using Golgi-staining. Stress effectiveness was confirmed by a significantly lower body weight and increased adrenal weight. In line with previous research, stressed animals displayed neuronal dendritic hypertrophy in the amygdala and hypotrophy in the hippocampal and medial prefrontal cortex. Using independent component analysis of resting-state fMRI data, we identified ten functional connectivity networks in the rodent brain. Chronic stress appeared to increase connectivity within the somatosensory, visual, and default mode networks. Moreover, chronic stress exposure was associated with an increased volume and diffusivity of the lateral ventricles, whereas no other volumetric changes were observed. This study shows that chronic stress exposure in rodents induces alterations in functional network connectivity strength which partly resemble those observed in stress-related psychopathology. Moreover, these functional consequences of stress seem to be more prominent than the effects on gross volumetric change, indicating their significance for future research.
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Affiliation(s)
- Marloes J A G Henckens
- Department of Neuroscience and Pharmacology, Rudolf Magnus Institute of Neuroscience, University Medical Center Utrecht, 3584 CG Utrecht, The Netherlands; Donders Institute for Brain, Cognition and Behaviour, Radboud University Nijmegen, 6500 HB Nijmegen, The Netherlands.
| | - Kajo van der Marel
- Biomedical MR Imaging and Spectroscopy Group, Image Sciences Institute, University Medical Center Utrecht, 3584 CX Utrecht, The Netherlands
| | - Annette van der Toorn
- Biomedical MR Imaging and Spectroscopy Group, Image Sciences Institute, University Medical Center Utrecht, 3584 CX Utrecht, The Netherlands
| | - Anup G Pillai
- Department of Neuroscience and Pharmacology, Rudolf Magnus Institute of Neuroscience, University Medical Center Utrecht, 3584 CG Utrecht, The Netherlands
| | - Guillén Fernández
- Donders Institute for Brain, Cognition and Behaviour, Radboud University Nijmegen, 6500 HB Nijmegen, The Netherlands; Department of Cognitive Neuroscience, Radboud University Medical Centre, 6500 HB Nijmegen, The Netherlands
| | - Rick M Dijkhuizen
- Biomedical MR Imaging and Spectroscopy Group, Image Sciences Institute, University Medical Center Utrecht, 3584 CX Utrecht, The Netherlands
| | - Marian Joëls
- Department of Neuroscience and Pharmacology, Rudolf Magnus Institute of Neuroscience, University Medical Center Utrecht, 3584 CG Utrecht, The Netherlands
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184
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Podestá MF, Yam P, Codagnone MG, Uccelli NA, Colman D, Reinés A. Distinctive PSA-NCAM and NCAM hallmarks in glutamate-induced dendritic atrophy and synaptic disassembly. PLoS One 2014; 9:e108921. [PMID: 25279838 PMCID: PMC4184824 DOI: 10.1371/journal.pone.0108921] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2013] [Accepted: 09/05/2014] [Indexed: 12/13/2022] Open
Abstract
Dendritic and synapse remodeling are forms of structural plasticity that play a critical role in normal hippocampal function. Neural cell adhesion molecule (NCAM) and its polysialylated form (PSA-NCAM) participate in neurite outgrowth and synapse formation and plasticity. However, it remains unclear whether they contribute to dendritic retraction and synaptic disassembly. Cultured hippocampal neurons exposed to glutamate (5 µM) showed a reduced MAP-2 (+) area in the absence of neuronal death 24 h after the insult. Concomitantly, synapse loss, revealed by decreased synaptophysin and post-synaptic density-95 cluster number and area, together with changes in NCAM and PSA-NCAM levels were found. Dendritic atrophy and PSA-NCAM reduction proved NMDA-receptor dependent. Live-imaging experiments evidenced dendritic atrophy 4 h after the insult; this effect was preceded by smaller NCAM clusters (1 h) and decreased surface and total PSA-NCAM levels (3 h). Simultaneously, total NCAM cluster number and area remained unchanged. The subsequent synapse disassembly (6 h) was accompanied by reductions in total NCAM cluster number and area. A PSA mimetic peptide prevented both the dendritic atrophy and the subsequent synaptic changes (6 h) but had no effect on the earliest synaptic remodeling (3 h). Thus, NCAM-synaptic reorganization and PSA-NCAM level decrease precede glutamate-induced dendritic atrophy, whereas the NCAM level reduction is a delayed event related to synapse loss. Consequently, distinctive stages in PSA-NCAM/NCAM balance seem to accompany glutamate-induced dendritic atrophy and synapse loss.
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Affiliation(s)
- María Fernanda Podestá
- Instituto de Investigaciones Farmacológicas (ININFA, CONICET-UBA), Ciudad Autónoma de Buenos Aires, Argentina
- Cátedra de Farmacología, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, Ciudad Autónoma de Buenos Aires, Argentina
- Instituto de Biología Celular y Neurociencias “Prof. E. De Robertis” (IBCN, CONICET-UBA), Ciudad Autónoma de Buenos Aires, Argentina
| | - Patricia Yam
- Montreal Neurological Institute and Hospital, McGill University, Montreal, Canada
| | - Martín Gabriel Codagnone
- Instituto de Investigaciones Farmacológicas (ININFA, CONICET-UBA), Ciudad Autónoma de Buenos Aires, Argentina
- Cátedra de Farmacología, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, Ciudad Autónoma de Buenos Aires, Argentina
- Instituto de Biología Celular y Neurociencias “Prof. E. De Robertis” (IBCN, CONICET-UBA), Ciudad Autónoma de Buenos Aires, Argentina
| | - Nonthué Alejandra Uccelli
- Instituto de Investigaciones Farmacológicas (ININFA, CONICET-UBA), Ciudad Autónoma de Buenos Aires, Argentina
- Cátedra de Farmacología, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, Ciudad Autónoma de Buenos Aires, Argentina
- Instituto de Biología Celular y Neurociencias “Prof. E. De Robertis” (IBCN, CONICET-UBA), Ciudad Autónoma de Buenos Aires, Argentina
| | - David Colman
- Montreal Neurological Institute and Hospital, McGill University, Montreal, Canada
| | - Analía Reinés
- Instituto de Investigaciones Farmacológicas (ININFA, CONICET-UBA), Ciudad Autónoma de Buenos Aires, Argentina
- Cátedra de Farmacología, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, Ciudad Autónoma de Buenos Aires, Argentina
- Instituto de Biología Celular y Neurociencias “Prof. E. De Robertis” (IBCN, CONICET-UBA), Ciudad Autónoma de Buenos Aires, Argentina
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185
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Joo EY, Kim H, Suh S, Hong SB. Hippocampal substructural vulnerability to sleep disturbance and cognitive impairment in patients with chronic primary insomnia: magnetic resonance imaging morphometry. Sleep 2014; 37:1189-98. [PMID: 25061247 DOI: 10.5665/sleep.3836] [Citation(s) in RCA: 130] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
STUDY OBJECTIVES Despite compelling evidence from animal studies indicating hippocampal subfield-specific vulnerability to poor sleep quality and related cognitive impairment, there have been no human magnetic resonance imaging (MRI) studies investigating the relationship between hippocampal subfield volume and sleep disturbance. Our aim was to investigate the pattern of volume changes across hippocampal subfields in patients with primary insomnia relative to controls. DESIGN Pointwise morphometry allowed for volume measurements of hippocampal regions on T1-weighted MRI. SETTING University hospital. PATIENTS Twenty-seven unmedicated patients (age: 51.2 ± 9.6 y) and 30 good sleepers as controls (50.4 ± 7.1 y). INTERVENTIONS N/A. MEASUREMENTS We compared hippocampal subfield volumes between patients and controls and correlated volume with clinical and neuropsychological features in patients. RESULTS Patients exhibited bilateral atrophy across all hippocampal subfields (P < 0.05 corrected). Cornu ammonis (CA) 1 subfield atrophy was associated with worse sleep quality (higher Pittsburgh Sleep Quality Index and higher arousal index of polysomnography) (r < -0.45, P < 0.005). The volume of the combined region, including the dentate gyrus (DG) and CA3-4, negatively correlated with verbal memory, verbal information processing, and verbal fluency in patients (|r| > 0.45, P < 0.05). Hemispheric volume asymmetry of this region (left smaller than right) was associated with impaired verbal domain functions (r = 0.50, P < 0.005). CONCLUSION Hippocampal subfield atrophy in chronic insomnia suggests reduced neurogenesis in the dentate gyrus (DG) and neuronal loss in the cornu ammonis (CA) subfields in conditions of sleep fragmentation and related chronic stress condition. Atrophy in the CA3-4-DG region was associated with impaired cognitive functions in patients. These observations may provide insight into pathophysiological mechanisms that make patients with chronic sleep disturbance vulnerable to cognitive impairment. CITATION Joo EY, Kim H, Suh S, Hong SB. Hippocampal substructural vulnerability to sleep disturbance and cognitive impairment in patients with chronic primary insomnia: magnetic resonance imaging morphometry.
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Affiliation(s)
- Eun Yeon Joo
- Sleep Center, Department of Neurology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Samsung Biomedical Research Institute, Seoul, Korea
| | - Hosung Kim
- Department of Neurology and Brain Imaging Center, Montreal Neurological Institute and Hospital, McGill University, Montreal, Quebec, Canada
| | - Sooyeon Suh
- Korea University Ansan Hospital, Human Genome Institute, Korea University, Seoul, Korea ; Stanford University, Department of Psychiatry, Redwood City, CA
| | - Seung Bong Hong
- Sleep Center, Department of Neurology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Samsung Biomedical Research Institute, Seoul, Korea
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186
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Tishkina AO, Stepanichev MY, Lazareva NA, Kulagina AO, Gulyaeva NV. The glial response in the rodent hippocampus to systemic administration of bacterial lipopolysaccharide. NEUROCHEM J+ 2014. [DOI: 10.1134/s1819712414020111] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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187
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Fuchs E, Flügge G. Adult neuroplasticity: more than 40 years of research. Neural Plast 2014; 2014:541870. [PMID: 24883212 PMCID: PMC4026979 DOI: 10.1155/2014/541870] [Citation(s) in RCA: 113] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2014] [Accepted: 04/09/2014] [Indexed: 01/04/2023] Open
Abstract
Within the last four decades, our view of the mature vertebrate brain has changed significantly. Today it is generally accepted that the adult brain is far from being fixed. A number of factors such as stress, adrenal and gonadal hormones, neurotransmitters, growth factors, certain drugs, environmental stimulation, learning, and aging change neuronal structures and functions. The processes that these factors may induce are morphological alterations in brain areas, changes in neuron morphology, network alterations including changes in neuronal connectivity, the generation of new neurons (neurogenesis), and neurobiochemical changes. Here we review several aspects of neuroplasticity and discuss the functional implications of the neuroplastic capacities of the adult and differentiated brain with reference to the history of their discovery.
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Affiliation(s)
- Eberhard Fuchs
- German Primate Center, Leibniz Institute for Primate Research, Kellnerweg 4, 37077 Göttingen, Germany
- Department of Neurology, Medical School, University of Göttingen, 37075 Göttingen, Germany
| | - Gabriele Flügge
- German Primate Center, Leibniz Institute for Primate Research, Kellnerweg 4, 37077 Göttingen, Germany
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188
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Seo MK, Lee CH, Cho HY, Lee JG, Lee BJ, Kim JE, Seol W, Kim YH, Park SW. Effects of antidepressant drugs on synaptic protein levels and dendritic outgrowth in hippocampal neuronal cultures. Neuropharmacology 2014; 79:222-33. [DOI: 10.1016/j.neuropharm.2013.11.019] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2013] [Revised: 11/07/2013] [Accepted: 11/21/2013] [Indexed: 01/28/2023]
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189
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Oster M, Muráni E, Ponsuksili S, D'Eath R, Turner S, Evans G, Thölking L, Kurt E, Klont R, Foury A, Mormède P, Wimmers K. Hepatic expression patterns in psychosocially high-stressed pigs suggest mechanisms following allostatic principles. Physiol Behav 2014; 128:159-65. [DOI: 10.1016/j.physbeh.2014.02.014] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2013] [Revised: 01/30/2014] [Accepted: 02/06/2014] [Indexed: 10/25/2022]
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190
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Loss of prion protein leads to age-dependent behavioral abnormalities and changes in cytoskeletal protein expression. Mol Neurobiol 2014; 50:923-36. [PMID: 24604355 DOI: 10.1007/s12035-014-8655-3] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2013] [Accepted: 01/29/2014] [Indexed: 12/13/2022]
Abstract
The cellular prion protein (PrPC) is a highly conserved protein whose exact physiological role remains elusive. In the present study, we investigated age-dependent behavioral abnormalities in PrPC-knockout (Prnp0/0) mice and wild-type (WT) controls. Prnp0/0 mice showed age-dependent behavioral deficits in memory performance, associative learning, basal anxiety, and nest building behavior. Using a hypothesis-free quantitative proteomic investigation, we found that loss of PrPC affected the levels of neurofilament proteins in an age-dependent manner. In order to understand the biochemical basis of these observations, we analyzed the phosphorylation status of neurofilament heavy chain (NF-H). We found a reduction in NF-H phosphorylation in both Prnp0/0 mice and in PrPC-deficient cells. The expression of Fyn and phospho-Fyn, a potential regulator for NF phosphorylation, was associated with PrPC ablation. The number of β-tubulin III-positive neurons in the hippocampus was diminished in Prnp0/0 mice relative to WT mice. These data indicate that PrPC plays an important role in cytoskeletal organization, brain function, and age-related neuroprotection. Our work represents the first direct biochemical link between these proteins and the observed behavioral phenotypes.
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191
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Chang Y, Pi W, Ang W, Liu Y, Li C, Zheng J, Xiong L, Yang T, Luo Y. Synthesis and evaluation of amide side-chain modified Agomelatine analogues as potential antidepressant-like agents. Bioorg Med Chem Lett 2014; 24:1672-6. [PMID: 24631187 DOI: 10.1016/j.bmcl.2014.02.065] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2013] [Revised: 02/19/2014] [Accepted: 02/21/2014] [Indexed: 02/05/2023]
Abstract
In this work, nineteen analogues of Agomelatine were readily synthesized through structural modification of the acetamide side-chain starting from the key common intermediate 2-(7-methoxynaphthalen-1-yl) ethanamine (3), which was prepared from commercially available compound 2-(7-methoxynaphthalen-1-yl) acetonitrile (2) in two steps. Corticosterone-induced PC12 pheochromocytoma cells phenotypic in vitro model was utilized to evaluate their potential antidepression activities. Imide compound 4a and acylamino carboxylic acid analogue 5b showed good protective effects on traumatic PC12 cells with protection rates of 34.2% and 23.2%, respectively. Further in vivo assessments in C57 mice FST (forced swim test) model demonstrated that compound 4a significantly reduced the immobility time of the tested subjects, indicating antidepressant-like activity. Preliminary toxicity assays conducted on human normal liver L02 cells and embryonic kidney 293 cells suggested a relatively low safety risk for compound 4a compared with the marketed drugs Agomelatine and Fluoxetine. The promising antidepressant-like efficacy of compound 4a, together with the relatively low toxicity to the normal tested cells and high liability of diffusion through the blood-brain barrier (BBB), presents us insights of exploration of me-better drug candidates of Agomelatine.
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Affiliation(s)
- Ying Chang
- National Key Laboratory of Biotherapy, West China Hospital, West China Medical School, Sichuan University, Chengdu, Sichuan 610041, PR China
| | - Weiyi Pi
- National Key Laboratory of Biotherapy, West China Hospital, West China Medical School, Sichuan University, Chengdu, Sichuan 610041, PR China
| | - Wei Ang
- Key Laboratory of Drug Targeting and Drug Delivery System, Ministry of Education, West China School of Pharmacy, Sichuan University, Chengdu, Sichuan 610041, PR China
| | - Yuanyuan Liu
- National Key Laboratory of Biotherapy, West China Hospital, West China Medical School, Sichuan University, Chengdu, Sichuan 610041, PR China
| | - Chunlong Li
- Pharmaceutical and Biological Engineering Department, Institute for Chemical Engineering, Sichuan University, Chengdu, Sichuan 610041, PR China
| | - Jiajia Zheng
- Pharmaceutical and Biological Engineering Department, Institute for Chemical Engineering, Sichuan University, Chengdu, Sichuan 610041, PR China
| | - Li Xiong
- Key Laboratory of Drug Targeting and Drug Delivery System, Ministry of Education, West China School of Pharmacy, Sichuan University, Chengdu, Sichuan 610041, PR China
| | - Tao Yang
- National Key Laboratory of Biotherapy, West China Hospital, West China Medical School, Sichuan University, Chengdu, Sichuan 610041, PR China
| | - Youfu Luo
- National Key Laboratory of Biotherapy, West China Hospital, West China Medical School, Sichuan University, Chengdu, Sichuan 610041, PR China.
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192
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Saaltink DJ, Vreugdenhil E. Stress, glucocorticoid receptors, and adult neurogenesis: a balance between excitation and inhibition? Cell Mol Life Sci 2014; 71:2499-515. [PMID: 24522255 PMCID: PMC4055840 DOI: 10.1007/s00018-014-1568-5] [Citation(s) in RCA: 85] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2013] [Revised: 12/26/2013] [Accepted: 01/16/2014] [Indexed: 02/06/2023]
Abstract
Adult neurogenesis, the birth of new neurons in the mature brain, has attracted considerable attention in the last decade. One of the earliest identified and most profound factors that affect adult neurogenesis both positively and negatively is stress. Here, we review the complex interplay between stress and adult neurogenesis. In particular, we review the role of the glucocorticoid receptor, the main mediator of the stress response in the proliferation, differentiation, migration, and functional integration of newborn neurons in the hippocampus. We review a multitude of mechanisms regulating glucocorticoid receptor activity in relationship to adult neurogenesis. We postulate a novel concept in which the level of glucocorticoid receptor expression directly regulates the excitation-inhibition balance, which is key for proper neurogenesis. We furthermore argue that an excitation-inhibition dis-balance may underlie aberrant functional integration of newborn neurons that is associated with psychiatric and paroxysmal brain disorders.
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Affiliation(s)
- Dirk-Jan Saaltink
- Department of Medical Pharmacology, Leiden University Medical Center/Leiden Amsterdam Center for Drug Research, 2300 RC, Leiden, The Netherlands
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193
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Mooney SJ, Peragine DE, Hathaway GA, Holmes MM. A game of thrones: Neural plasticity in mammalian social hierarchies. Soc Neurosci 2014; 9:108-17. [DOI: 10.1080/17470919.2014.882862] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
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194
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Yau SY, So KF. Adult neurogenesis and dendritic remodeling in hippocampal plasticity: which one is more important? Cell Transplant 2014; 23:471-9. [PMID: 24636187 DOI: 10.3727/096368914x678283] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Accumulating knowledge has shown that a decrease in hippocampal neurogenesis is linked to the pathophysiology of mood disorders and some hippocampal-dependent learning and memory tasks. The role of adult neurogenesis has initially been proposed based on correlations between decreases or increases in neurogenesis and impairments or improvements, respectively, in animal behaviors following interventions. Its role has been further elucidated through the ablation of neurogenesis. However, the functional roles of neurogenesis in hippocampal-dependent behaviors have been challenged by inconsistent findings between different studies. Despite the fact that factors affecting neurogenesis also induce dendritic or synaptic changes in newborn or existing neurons, these two aspects of structural changes within the hippocampus have always been examined separately. Thus, it is difficult to interpret the functional role of adult neurogenesis or dendritic remodification in hippocampal-dependent behaviors. This review discusses the relative contribution of adult neurogenesis and dendritic/synaptic remodeling of existing neurons to hippocampal plasticity.
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Affiliation(s)
- Suk-Yu Yau
- Department of Anatomy, The University of Hong Kong, Pokfulam, Hong Kong
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195
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van Ooyen A, Carnell A, de Ridder S, Tarigan B, Mansvelder HD, Bijma F, de Gunst M, van Pelt J. Independently outgrowing neurons and geometry-based synapse formation produce networks with realistic synaptic connectivity. PLoS One 2014; 9:e85858. [PMID: 24454938 PMCID: PMC3894200 DOI: 10.1371/journal.pone.0085858] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2013] [Accepted: 12/03/2013] [Indexed: 11/18/2022] Open
Abstract
Neuronal signal integration and information processing in cortical networks critically depend on the organization of synaptic connectivity. During development, neurons can form synaptic connections when their axonal and dendritic arborizations come within close proximity of each other. Although many signaling cues are thought to be involved in guiding neuronal extensions, the extent to which accidental appositions between axons and dendrites can already account for synaptic connectivity remains unclear. To investigate this, we generated a local network of cortical L2/3 neurons that grew out independently of each other and that were not guided by any extracellular cues. Synapses were formed when axonal and dendritic branches came by chance within a threshold distance of each other. Despite the absence of guidance cues, we found that the emerging synaptic connectivity showed a good agreement with available experimental data on spatial locations of synapses on dendrites and axons, number of synapses by which neurons are connected, connection probability between neurons, distance between connected neurons, and pattern of synaptic connectivity. The connectivity pattern had a small-world topology but was not scale free. Together, our results suggest that baseline synaptic connectivity in local cortical circuits may largely result from accidentally overlapping axonal and dendritic branches of independently outgrowing neurons.
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Affiliation(s)
- Arjen van Ooyen
- Department of Integrative Neurophysiology, Center for Neurogenomics and Cognitive Research, VU University Amsterdam, Amsterdam, The Netherlands
| | - Andrew Carnell
- Department of Integrative Neurophysiology, Center for Neurogenomics and Cognitive Research, VU University Amsterdam, Amsterdam, The Netherlands
| | - Sander de Ridder
- Department of Integrative Neurophysiology, Center for Neurogenomics and Cognitive Research, VU University Amsterdam, Amsterdam, The Netherlands
| | - Bernadetta Tarigan
- Department of Mathematics, VU University Amsterdam, Amsterdam, The Netherlands
| | - Huibert D. Mansvelder
- Department of Integrative Neurophysiology, Center for Neurogenomics and Cognitive Research, VU University Amsterdam, Amsterdam, The Netherlands
| | - Fetsje Bijma
- Department of Mathematics, VU University Amsterdam, Amsterdam, The Netherlands
| | - Mathisca de Gunst
- Department of Mathematics, VU University Amsterdam, Amsterdam, The Netherlands
| | - Jaap van Pelt
- Department of Integrative Neurophysiology, Center for Neurogenomics and Cognitive Research, VU University Amsterdam, Amsterdam, The Netherlands
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196
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Frodl T, Amico F. Is there an association between peripheral immune markers and structural/functional neuroimaging findings? Prog Neuropsychopharmacol Biol Psychiatry 2014; 48:295-303. [PMID: 23313563 DOI: 10.1016/j.pnpbp.2012.12.013] [Citation(s) in RCA: 104] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/04/2012] [Revised: 11/14/2012] [Accepted: 12/15/2012] [Indexed: 02/04/2023]
Abstract
OBJECTIVES There is mounting evidence that inflammatory processes play a key role in emotional as well as cognitive dysfunctions. In this context, research employing magnetic resonance imaging (MRI) and magnetic resonance spectroscopy (MR spectroscopy) suggests a possible link between structural/functional anomalies in the brain and an increase of circulating inflammation markers. The present paper reviews this research, with particular focus on major depressive disorder (MDD), cognitive impairment in older adults, Alzheimer's disease (AD) and schizophrenia. RESULTS In MDD, cognitive impairment and AD, inflammatory processes have been found to be associated with both structural and functional anomalies, perhaps under the influence of environmental stress. Not enough research can suggest similar considerations in schizophrenia, although studies in mice and non-human primates support the belief that inflammatory responses generated during pregnancy can affect brain development and contribute to the etiology of schizophrenia. CONCLUSIONS The present review suggests a link between inflammatory processes and MRI detected anomalies in the brain of individuals with MDD, older adults with cognitive impairment as well as of individuals with AD and schizophrenia.
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Affiliation(s)
- Thomas Frodl
- Department of Psychiatry, Trinity College Institute of Neuroscience, Trinity College, Dublin, Ireland; Adelaide and Meath incorporating the National's Children Hospital, Dublin, Ireland; St. James's Hospital, Dublin, Ireland.
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197
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Lucassen PJ, Pruessner J, Sousa N, Almeida OFX, Van Dam AM, Rajkowska G, Swaab DF, Czéh B. Neuropathology of stress. Acta Neuropathol 2014; 127:109-35. [PMID: 24318124 PMCID: PMC3889685 DOI: 10.1007/s00401-013-1223-5] [Citation(s) in RCA: 285] [Impact Index Per Article: 28.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2013] [Accepted: 11/26/2013] [Indexed: 02/06/2023]
Abstract
Environmental challenges are part of daily life for any individual. In fact, stress appears to be increasingly present in our modern, and demanding, industrialized society. Virtually every aspect of our body and brain can be influenced by stress and although its effects are partly mediated by powerful corticosteroid hormones that target the nervous system, relatively little is known about when, and how, the effects of stress shift from being beneficial and protective to becoming deleterious. Decades of stress research have provided valuable insights into whether stress can directly induce dysfunction and/or pathological alterations, which elements of stress exposure are responsible, and which structural substrates are involved. Using a broad definition of pathology, we here review the "neuropathology of stress" and focus on structural consequences of stress exposure for different regions of the rodent, primate and human brain. We discuss cytoarchitectural, neuropathological and structural plasticity measures as well as more recent neuroimaging techniques that allow direct monitoring of the spatiotemporal effects of stress and the role of different CNS structures in the regulation of the hypothalamic-pituitary-adrenal axis in human brain. We focus on the hypothalamus, hippocampus, amygdala, nucleus accumbens, prefrontal and orbitofrontal cortex, key brain regions that not only modulate emotions and cognition but also the response to stress itself, and discuss disorders like depression, post-traumatic stress disorder, Cushing syndrome and dementia.
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Affiliation(s)
- Paul J. Lucassen
- SILS-Center for Neuroscience, University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands
| | - Jens Pruessner
- Department of Psychiatry, Douglas Institute, McGill University, Montreal, QC Canada
| | - Nuno Sousa
- Life and Health Sciences Research Institute (ICVS), School of Health Sciences, University of Minho, Campus Gualtar, 4710-057 Braga, Portugal
- ICVS/3B’s-PT Government Associate Laboratory, Braga, Guimarães, Portugal
| | | | - Anne Marie Van Dam
- Department of Anatomy and Neurosciences, VU University Medical Center, Neuroscience Campus Amsterdam, Amsterdam, The Netherlands
| | - Grazyna Rajkowska
- Department of Psychiatry and Human Behavior, University of Mississippi Medical Center, Jackson, MS USA
| | - Dick F. Swaab
- Netherlands Institute for Neuroscience, An Institute of the Royal Netherlands Academy of Arts and Sciences, Amsterdam, The Netherlands
| | - Boldizsár Czéh
- Department of Laboratory Medicine, Faculty of Medicine, University of Pécs, Pécs, Hungary
- Szentágothai János Research Center, Neuroendocrinology Research Group, University of Pécs, Pécs, Hungary
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198
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Daulatzai MA. Role of stress, depression, and aging in cognitive decline and Alzheimer's disease. Curr Top Behav Neurosci 2014; 18:265-96. [PMID: 25167923 DOI: 10.1007/7854_2014_350] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Late-onset Alzheimer's disease (AD) is a chronic neurodegenerative disorder and the most common cause of progressive cognitive dysfunction and dementia. Despite considerable progress in elucidating the molecular pathology of this disease, we are not yet close to unraveling its etiopathogenesis. A battery of neurotoxic modifiers may underpin neurocognitive pathology via deleterious heterogeneous pathologic impact in brain regions, including the hippocampus. Three important neurotoxic factors being addressed here include aging, stress, and depression. Unraveling "upstream pathologies" due to these disparate neurotoxic entities, vis-à-vis cognitive impairment involving hippocampal dysfunction, is of paramount importance. Persistent systemic inflammation triggers and sustains neuroinflammation. The latter targets several brain regions including the hippocampus causing upregulation of amyloid beta and neurofibrillary tangles, synaptic and neuronal degeneration, gray matter volume atrophy, and progressive cognitive decline. However, what is the fundamental source of this peripheral inflammation in aging, stress, and depression? This chapter highlights and delineates the inflammatory involvement-i.e., from its inception from gut to systemic inflammation to neuroinflammation. It highlights an upregulated cascade in which gut-microbiota-related dysbiosis generates lipopolysaccharides (LPS), which enhances inflammation and gut's leakiness, and through a Web of interactions, it induces stress and depression. This may increase neuronal dysfunction and apoptosis, promote learning and memory impairment, and enhance vulnerability to cognitive decline.
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Affiliation(s)
- Mak Adam Daulatzai
- Sleep Disorders Group, EEE Department, Melbourne School of Engineering, The University of Melbourne, Building 193, 3rd Floor, Room no. 3/344, Parkville, VIC, 3010, Australia,
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199
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Smith C, van Vuuren MJ. Central and peripheral effects of Sutherlandia frutescens on the response to acute psychological stress. Exp Biol Med (Maywood) 2013; 239:123-8. [DOI: 10.1177/1535370213510253] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Sutherlandia frutescens is widely used in indigenous medicine for the treatment of stress- and anxiety-related disorders, and although anecdotal evidence has been scientifically confirmed, relatively little data are available on its potential mechanisms of action. We manipulated a rodent model of acute psychological stress by acutely administering a low dose (4 mg/kg body mass) of S. frutescens extract 30 min prior to stress exposure (1 h restraint), to elucidate both its central and peripheral mechanisms of action in the context of acute stress. After 1 h of exposure to stress, acute restraint resulted in a significant increase in plasma corticosterone levels (56 ± 33 versus 499 ± 50 ng/ml; P < 0.0001) and anterior pituitary adrenocorticotropic hormone (ACTH) levels (0.066 ± 0.017 versus 0.202 ± 0.033% fluorescent area; P = 0.07), while decreasing hippocampal glucocorticoid receptor (GR) and gamma-aminobutyric acid (GABA)(A)α1 receptor levels (both P < 0.05). While the low dose of S. frutescens administered did not seem to have an effect on the down-stream stress response, it abolished the stress-induced down-regulation of GR, in a manner independent of GABA(A)α1 receptor. Results suggest a non-sedative effect of low-dose S. frutescens and points to central mechanisms of action that is in support of the anecdotal claims for its effectiveness as complimentary treatment in chronic stress-associated diseases.
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Affiliation(s)
- Carine Smith
- Department Physiological Sciences, Stellenbosch University, Stellenbosch, 7602, South Africa
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200
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Shih PC, Yang YR, Wang RY. Effects of exercise intensity on spatial memory performance and hippocampal synaptic plasticity in transient brain ischemic rats. PLoS One 2013; 8:e78163. [PMID: 24205142 PMCID: PMC3808358 DOI: 10.1371/journal.pone.0078163] [Citation(s) in RCA: 93] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2013] [Accepted: 09/17/2013] [Indexed: 12/17/2022] Open
Abstract
Memory impairment is commonly noted in stroke survivors, and can lead to delay of functional recovery. Exercise has been proved to improve memory in adult healthy subjects. Such beneficial effects are often suggested to relate to hippocampal synaptic plasticity, which is important for memory processing. Previous evidence showed that in normal rats, low intensity exercise can improve synaptic plasticity better than high intensity exercise. However, the effects of exercise intensities on hippocampal synaptic plasticity and spatial memory after brain ischemia remain unclear. In this study, we investigated such effects in brain ischemic rats. The middle cerebral artery occlusion (MCAO) procedure was used to induce brain ischemia. After the MCAO procedure, rats were randomly assigned to sedentary (Sed), low-intensity exercise (Low-Ex), or high-intensity exercise (High-Ex) group. Treadmill training began from the second day post MCAO procedure, 30 min/day for 14 consecutive days for the exercise groups. The Low-Ex group was trained at the speed of 8 m/min, while the High-Ex group at the speed of 20 m/min. The spatial memory, hippocampal brain-derived neurotrophic factor (BDNF), synapsin-I, postsynaptic density protein 95 (PSD-95), and dendritic structures were examined to document the effects. Serum corticosterone level was also quantified as stress marker. Our results showed the Low-Ex group, but not the High-Ex group, demonstrated better spatial memory performance than the Sed group. Dendritic complexity and the levels of BDNF and PSD-95 increased significantly only in the Low-Ex group as compared with the Sed group in bilateral hippocampus. Notably, increased level of corticosterone was found in the High-Ex group, implicating higher stress response. In conclusion, after brain ischemia, low intensity exercise may result in better synaptic plasticity and spatial memory performance than high intensity exercise; therefore, the intensity is suggested to be considered during exercise training.
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Affiliation(s)
- Pei-Cheng Shih
- Department of Physical Therapy and Assistive Technology, National Yang-Ming University, Taipei, Taiwan
- Department of Physical Therapy, Mackay Memorial Hospital, Taipei, Taiwan
| | - Yea-Ru Yang
- Department of Physical Therapy and Assistive Technology, National Yang-Ming University, Taipei, Taiwan
| | - Ray-Yau Wang
- Department of Physical Therapy and Assistive Technology, National Yang-Ming University, Taipei, Taiwan
- * E-mail:
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