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Horwitz RI, Singer BH, Seeman TE. Biology and Lived Experience in Health and Disease: A Tribute to Bruce McEwen (1938-2020), a Scientist without Silos. PSYCHOTHERAPY AND PSYCHOSOMATICS 2021; 90:5-10. [PMID: 33171463 DOI: 10.1159/000512598] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/26/2020] [Accepted: 10/27/2020] [Indexed: 11/19/2022]
Affiliation(s)
- Ralph I Horwitz
- Temple University School of Medicine, Philadelphia, Pennsylvania, USA,
| | - Burton H Singer
- Emerging Pathogens Institute, University of Florida, Gainesville, Florida, USA
| | - Teresa E Seeman
- David Geffen School of Medicine, University of California Los Angeles, Los Angeles, California, USA
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2
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Marrocco J. Bruce S. McEwen: the evolution of stress. Stress 2020; 23:497-498. [PMID: 32795104 DOI: 10.1080/10253890.2020.1803266] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/23/2022] Open
Affiliation(s)
- Jordan Marrocco
- Harold and Margaret Milliken Hatch Laboratory of Neuroendocrinology, The Rockefeller University, New York, NY, USA
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3
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From serendipity to clinical relevance: How clinical psychology and neuroscience converged to illuminate psychoneuroendocrinology. Psychoneuroendocrinology 2019; 105:36-43. [PMID: 30309685 DOI: 10.1016/j.psyneuen.2018.09.011] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/09/2018] [Revised: 09/01/2018] [Accepted: 09/10/2018] [Indexed: 01/01/2023]
Abstract
Dirk Hellhammer and his colleagues have played a major role in creating the field of psychoneuroendocrinology from their roots in psychology. In this review, using examples from the history of the McEwen laboratory and neuroscience and neuroendocrinology colleagues, I summarize my own perspective as to how the fields of neuroscience and neuroendocrinology have contributed to psychoneuroendocrinology and how they converged with the contributions from Dirk Hellhammer and his colleagues.
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4
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Baraban SC. Viral tracing of presynaptic inputs to newly born dentate granule cells in a rodent model of mesial temporal lobe epilepsy. Ann Neurol 2019; 81:769-771. [PMID: 28470692 DOI: 10.1002/ana.24945] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2017] [Revised: 04/17/2017] [Accepted: 04/26/2017] [Indexed: 11/07/2022]
Affiliation(s)
- Scott C Baraban
- Department of Neurological Surgery and Weill Institute for Neurosciences, University of California, San Francisco San Francisco, CA
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5
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McEwen BS. Redefining neuroendocrinology: Epigenetics of brain-body communication over the life course. Front Neuroendocrinol 2018; 49:8-30. [PMID: 29132949 DOI: 10.1016/j.yfrne.2017.11.001] [Citation(s) in RCA: 49] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/29/2017] [Revised: 11/01/2017] [Accepted: 11/04/2017] [Indexed: 12/15/2022]
Abstract
The brain is the central organ of stress and adaptation to stress that perceives and determines what is threatening, as well as the behavioral and physiological responses to the stressor, and it does so somewhat differently in males and females. The expression of steroid hormone receptors throughout the brain has broadened the definition of 'neuroendocrinology' to include the reciprocal communication between the entire brain and body via hormonal and neural pathways. Mediated in part via systemic hormonal influences, the adult and developing brain possess remarkable structural and functional plasticity in response to stress, including neuronal replacement, dendritic remodeling, and synapse turnover. This article is both an account of an emerging field elucidating brain-body interactions at multiple levels, from molecules to social organization, as well as a personal account of my laboratory's role and, most importantly, the roles of trainees and colleagues, along with my involvement in interdisciplinary groups working on this topic.
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Affiliation(s)
- Bruce S McEwen
- Laboratory of Neuroendocrinology, The Rockefeller University, 1230 York Ave, New York, NY 10065, USA. http://www.rockefeller.edu/labheads/mcewen/mcewen-lab.php
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6
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McEwen BS, Milner TA. Understanding the broad influence of sex hormones and sex differences in the brain. J Neurosci Res 2017; 95:24-39. [PMID: 27870427 PMCID: PMC5120618 DOI: 10.1002/jnr.23809] [Citation(s) in RCA: 343] [Impact Index Per Article: 49.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2016] [Revised: 05/23/2016] [Accepted: 06/10/2016] [Indexed: 12/11/2022]
Abstract
Sex hormones act throughout the entire brain of both males and females via both genomic and nongenomic receptors. Sex hormones can act through many cellular and molecular processes that alter structure and function of neural systems and influence behavior as well as providing neuroprotection. Within neurons, sex hormone receptors are found in nuclei and are also located near membranes, where they are associated with presynaptic terminals, mitochondria, spine apparatus, and postsynaptic densities. Sex hormone receptors also are found in glial cells. Hormonal regulation of a variety of signaling pathways as well as direct and indirect effects on gene expression induce spine synapses, up- or downregulate and alter the distribution of neurotransmitter receptors, and regulate neuropeptide expression and cholinergic and GABAergic activity as well as calcium sequestration and oxidative stress. Many neural and behavioral functions are affected, including mood, cognitive function, blood pressure regulation, motor coordination, pain, and opioid sensitivity. Subtle sex differences exist for many of these functions that are developmentally programmed by hormones and by not yet precisely defined genetic factors, including the mitochondrial genome. These sex differences and responses to sex hormones in brain regions, which influence functions not previously regarded as subject to such differences, indicate that we are entering a new era of our ability to understand and appreciate the diversity of gender-related behaviors and brain functions. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Bruce S. McEwen
- Harold and Margaret Milliken Hatch Laboratory of Neuroendocrinology, The Rockefeller University, 1230 York Avenue, New York, NY 10065
| | - Teresa A. Milner
- Harold and Margaret Milliken Hatch Laboratory of Neuroendocrinology, The Rockefeller University, 1230 York Avenue, New York, NY 10065
- Feil Family Brain and Mind Research Institute, Weill Cornell School of Medicine, 407 East 61st Street, New York, NY 10065
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7
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Llorens-Martín M, Teixeira CM, Jurado-Arjona J, Rakwal R, Shibato J, Soya H, Ávila J. Retroviral induction of GSK-3β expression blocks the stimulatory action of physical exercise on the maturation of newborn neurons. Cell Mol Life Sci 2016; 73:3569-82. [PMID: 27010990 PMCID: PMC11108461 DOI: 10.1007/s00018-016-2181-6] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2015] [Revised: 03/10/2016] [Accepted: 03/11/2016] [Indexed: 10/22/2022]
Abstract
Adult hippocampal neurogenesis (AHN) is a key process for certain types of hippocampal-dependent learning. Alzheimer's disease (AD) is accompanied by memory deficits related to alterations in AHN. Given that the increased activity of GSK-3β has been related to alterations in the population of hippocampal granule neurons in AD patients, we designed a novel methodology by which to induce selective GSK-3β overexpression exclusively in newborn granule neurons. To this end, we injected an rtTA-IRES-EGFP-expressing retrovirus into the hippocampus of tTO-GSK-3β mice. Using this novel retroviral strategy, we found that GSK-3β caused a cell-autonomous impairment of the morphological and synaptic maturation of newborn neurons. In addition, we examined whether GSK-3β overexpression in newborn neurons limits the effects of physical activity. While physical exercise increased the number of dendritic spines, the percentage of mushroom spines, and the head diameter of the same in tet-OFF cells, these effects were not triggered in tet-ON cells. This observation suggests that GSK-3β blocks the stimulatory actions of exercise. Given that the activity of GSK-3β is increased in the brains of individuals with AD, these data may be relevant for non-pharmacological therapies for AD.
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Affiliation(s)
- María Llorens-Martín
- Centro de Biología Molecular "Severo Ochoa" (CSIC-UAM), Universidad Autónoma de Madrid, c/Nicolás Cabrera 1, 28049, Madrid, Spain.
- Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED, ISCIII), c/Valderrebollo 5, Madrid, Spain.
| | - Catia M Teixeira
- Emotional Brain Institute, Nathan Kline Institute, New York, NY, USA
| | - Jerónimo Jurado-Arjona
- Centro de Biología Molecular "Severo Ochoa" (CSIC-UAM), Universidad Autónoma de Madrid, c/Nicolás Cabrera 1, 28049, Madrid, Spain
- Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED, ISCIII), c/Valderrebollo 5, Madrid, Spain
| | - Randeep Rakwal
- Faculty of Health and Sport Sciences and Tsukuba International Academy for Sport Studies (TIAS), University of Tsukuba, Tsukuba, Ibaraki, 305-8574, Japan
- Global Research Center for Innovative Life Science, School of Pharmacy and Pharmaceutical Sciences, Hoshi University, Shinagawa, Tokyo, 142-8501, Japan
| | - Junko Shibato
- Global Research Center for Innovative Life Science, School of Pharmacy and Pharmaceutical Sciences, Hoshi University, Shinagawa, Tokyo, 142-8501, Japan
- Laboratory of Exercise Biochemistry and Neuroendocrinology, Faculty of Health and Sport Sciences, University of Tsukuba, Tsukuba, Ibaraki, 305-8574, Japan
| | - Hideaki Soya
- Laboratory of Exercise Biochemistry and Neuroendocrinology, Faculty of Health and Sport Sciences, University of Tsukuba, Tsukuba, Ibaraki, 305-8574, Japan
| | - Jesús Ávila
- Centro de Biología Molecular "Severo Ochoa" (CSIC-UAM), Universidad Autónoma de Madrid, c/Nicolás Cabrera 1, 28049, Madrid, Spain.
- Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED, ISCIII), c/Valderrebollo 5, Madrid, Spain.
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8
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Balthazart J, Ball GF. Endocrine and social regulation of adult neurogenesis in songbirds. Front Neuroendocrinol 2016; 41:3-22. [PMID: 26996818 DOI: 10.1016/j.yfrne.2016.03.003] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/12/2015] [Revised: 03/16/2016] [Accepted: 03/16/2016] [Indexed: 01/07/2023]
Abstract
The identification of pronounced seasonal changes in the volume of avian song control nuclei stimulated the discovery of adult neurogenesis in songbirds as well as renewed studies in mammals including humans. Neurogenesis in songbirds is modulated by testosterone and other factors such as photoperiod, singing activity and social environment. Adult neurogenesis has been widely studied by labeling, with tritiated thymidine or its analog BrdU, cells duplicating their DNA in anticipation of their last mitotic division and following their fate as new neurons. New methods based on endogenous markers of cell cycling or of various stages of neuronal life have allowed for additional progress. In particular immunocytochemical visualization of the microtubule-associated protein doublecortin has provided an integrated view of neuronal replacement in the song control nucleus HVC. Multiple questions remain however concerning the specific steps in the neuronal life cycle that are modulated by various factors and the underlying cellular mechanisms.
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Affiliation(s)
| | - Gregory F Ball
- Department of Psychology, University of Maryland, College Park, College Park, MD, USA.
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Matsuzaki K, Katakura M, Inoue T, Hara T, Hashimoto M, Shido O. Aging attenuates acquired heat tolerance and hypothalamic neurogenesis in rats. J Comp Neurol 2015; 523:1190-201. [DOI: 10.1002/cne.23732] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2014] [Revised: 12/15/2014] [Accepted: 12/16/2014] [Indexed: 11/08/2022]
Affiliation(s)
- Kentaro Matsuzaki
- Department of Environmental Physiology; Faculty of Medicine, Shimane University; Izumo 693-8501 Japan
| | - Masanori Katakura
- Department of Environmental Physiology; Faculty of Medicine, Shimane University; Izumo 693-8501 Japan
| | - Takayuki Inoue
- Department of Environmental Physiology; Faculty of Medicine, Shimane University; Izumo 693-8501 Japan
| | - Toshiko Hara
- Department of Environmental Physiology; Faculty of Medicine, Shimane University; Izumo 693-8501 Japan
| | - Michio Hashimoto
- Department of Environmental Physiology; Faculty of Medicine, Shimane University; Izumo 693-8501 Japan
| | - Osamu Shido
- Department of Environmental Physiology; Faculty of Medicine, Shimane University; Izumo 693-8501 Japan
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10
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Newman AJ, Hayes SH, Rao AS, Allman BL, Manohar S, Ding D, Stolzberg D, Lobarinas E, Mollendorf JC, Salvi R. Low-cost blast wave generator for studies of hearing loss and brain injury: blast wave effects in closed spaces. J Neurosci Methods 2015; 242:82-92. [PMID: 25597910 DOI: 10.1016/j.jneumeth.2015.01.009] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2014] [Revised: 12/12/2014] [Accepted: 01/07/2015] [Indexed: 01/24/2023]
Abstract
BACKGROUND Military personnel and civilians living in areas of armed conflict have increased risk of exposure to blast overpressures that can cause significant hearing loss and/or brain injury. The equipment used to simulate comparable blast overpressures in animal models within laboratory settings is typically very large and prohibitively expensive. NEW METHOD To overcome the fiscal and space limitations introduced by previously reported blast wave generators, we developed a compact, low-cost blast wave generator to investigate the effects of blast exposures on the auditory system and brain. RESULTS The blast wave generator was constructed largely from off the shelf components, and reliably produced blasts with peak sound pressures of up to 198dB SPL (159.3kPa) that were qualitatively similar to those produced from muzzle blasts or explosions. Exposure of adult rats to 3 blasts of 188dB peak SPL (50.4kPa) resulted in significant loss of cochlear hair cells, reduced outer hair cell function and a decrease in neurogenesis in the hippocampus. COMPARISON TO EXISTING METHODS Existing blast wave generators are typically large, expensive, and are not commercially available. The blast wave generator reported here provides a low-cost method of generating blast waves in a typical laboratory setting. CONCLUSIONS This compact blast wave generator provides scientists with a low cost device for investigating the biological mechanisms involved in blast wave injury to the rodent cochlea and brain that may model many of the damaging effects sustained by military personnel and civilians exposed to intense blasts.
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Affiliation(s)
- Andrew J Newman
- Department of Mechanical and Aerospace Engineering, University at Buffalo, The State University of New York, Buffalo, NY, United States.
| | - Sarah H Hayes
- Center for Hearing & Deafness, Department of Communicative Disorders and Sciences, University at Buffalo, The State University of New York, Buffalo, NY, United States.
| | - Abhiram S Rao
- Department of Mechanical and Aerospace Engineering, University at Buffalo, The State University of New York, Buffalo, NY, United States.
| | - Brian L Allman
- Center for Hearing & Deafness, Department of Communicative Disorders and Sciences, University at Buffalo, The State University of New York, Buffalo, NY, United States.
| | - Senthilvelan Manohar
- Center for Hearing & Deafness, Department of Communicative Disorders and Sciences, University at Buffalo, The State University of New York, Buffalo, NY, United States.
| | - Dalian Ding
- Center for Hearing & Deafness, Department of Communicative Disorders and Sciences, University at Buffalo, The State University of New York, Buffalo, NY, United States.
| | - Daniel Stolzberg
- Center for Hearing & Deafness, Department of Communicative Disorders and Sciences, University at Buffalo, The State University of New York, Buffalo, NY, United States.
| | - Edward Lobarinas
- Center for Hearing & Deafness, Department of Communicative Disorders and Sciences, University at Buffalo, The State University of New York, Buffalo, NY, United States.
| | - Joseph C Mollendorf
- Department of Mechanical and Aerospace Engineering, University at Buffalo, The State University of New York, Buffalo, NY, United States.
| | - Richard Salvi
- Center for Hearing & Deafness, Department of Communicative Disorders and Sciences, University at Buffalo, The State University of New York, Buffalo, NY, United States.
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11
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Abstract
As the central organ of stress and adaptation to stressors, the brain plays a pivotal role in behavioral and physiological responses that may lead to successful adaptation or to pathophysiology and mental and physical disease. In this context, resilience can be defined as "achieving a positive outcome in the face of adversity". Underlying this deceptively simple statement are several questions; first, to what extent is this ability limited to those environments that have shaped the individual or can it be more flexible; second, when in the life course does the brain develop capacity for flexibility for adapting positively to new challenges; and third, can such flexibility be instated in individuals where early life experiences have limited that capacity? Brain architecture continues to show plasticity throughout adult life and studies of gene expression and epigenetic regulation reveal a dynamic and ever-changing brain. The goal is to recognize those biological changes that underlie flexible adaptability, and to recognize gene pathways, epigenetic factors and structural changes that indicate lack of resilience leading to negative outcomes, particularly when the individual is challenged by new circumstances. Early life experiences determine individual differences in such capabilities via epigenetic pathways and laying down of brain architecture that determine the later capacity for flexible adaptation or the lack thereof. Reactivation of such plasticity in individuals lacking such resilience is a new challenge for research and practical application. Finally, sex differences in the plasticity of the brain are often overlooked and must be more fully investigated.
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Affiliation(s)
- Bruce S. McEwen
- Laboratory of Neuroendocrinology, The Rockefeller University, 1230 York Avenue, New York, NY 10065, USA
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12
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Teh DBL, Ishizuka T, Yawo H. Regulation of later neurogenic stages of adult-derived neural stem/progenitor cells by L-type Ca2+ channels. Dev Growth Differ 2014; 56:583-94. [PMID: 25283796 DOI: 10.1111/dgd.12158] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2014] [Revised: 08/15/2014] [Accepted: 08/15/2014] [Indexed: 11/30/2022]
Abstract
In the adult hippocampus, new neurons are continuously generated and incorporated into the local circuitry in a manner dependent on the network activity. Depolarization evoked by neurotransmitters has been assumed to activate L-type Ca2+ channels (LTCC) which regulate the intracellular Ca2+ -dependent signaling cascades. The process of neurogenesis contains several stages such as proliferation, fate determination, selective death/survival and maturation. Here, we investigated which stage of neurogenesis is under the regulation of LTCC using a clonal line of neural stem/progenitor cells, PZ5, which was derived from adult rat hippocampus. Although undifferentiated PZ5 cells were type 1-like cells expressing both nestin and glial fibrillary acidic protein, they generated neuronal, astrocytic and oligodendrocytic populations in differentiation medium containing retinoic acid. Proliferation of undifferentiated PZ5 cells was dependent on neither the LTCC antagonist, nimodipine (Nimo) nor the LTCC agonists, Bay K 8644 (BayK) or FPL 64176 (FPL), whereas the fraction of neuronal population that expressed both βIII-tubulin and MAP2 was reduced by Nimo but increased by BayK or FPL. At an earlier period of differentiation (e.g., day 4), the fraction of PZ5 cells expressing HuC/D, pan-neuronal marker, was not affected either by the LTCC activation or inhibition. At a later period of differentiation (e.g., day 9), the fraction of dying neurons was decreased by LTCC activation and increased by LTCC inhibition. It is suggested that the LTCC activation facilitates the survival and maturation of immature neurons, and that its inhibition facilitates the neuronal death.
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Affiliation(s)
- Daniel B L Teh
- Department of Developmental Biology and Neuroscience, Tohoku University Graduate School of Life Sciences, Tokyo, Japan
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McEwen BS. Sex, stress and the brain: interactive actions of hormones on the developing and adult brain. Climacteric 2014; 17 Suppl 2:18-25. [PMID: 25225752 DOI: 10.3109/13697137.2014.949662] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
The brain is a target of steroid hormone actions that affect brain architecture, molecular and neurochemical processes, behavior and neuroprotection via both genomic and non-genomic actions. Estrogens have such effects throughout the brain and this article provides an historical and current view of how this new view has come about and how it has affected the study of sex differences, as well as other areas of neuroscience, including the effects of stress on the brain.
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Affiliation(s)
- B S McEwen
- Alfred E. Mirsky Professor, Head, Harold and Margaret Milliken Hatch, Laboratory of Neuroendocrinology, The Rockefeller University , New York, NY , USA
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14
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Balthazart J, Ball GF. Endogenous versus exogenous markers of adult neurogenesis in canaries and other birds: advantages and disadvantages. J Comp Neurol 2014; 522:4100-20. [PMID: 25131458 DOI: 10.1002/cne.23661] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2013] [Revised: 03/17/2014] [Accepted: 08/04/2014] [Indexed: 02/03/2023]
Abstract
Although the existence of newborn neurons had originally been suggested, but not broadly accepted, based on studies in adult rodent brains, the presence of an active neurogenesis process in adult homoeothermic vertebrates was first firmly established in songbirds. Adult neurogenesis was initially studied with the tritiated thymidine technique, later replaced by the injection and detection of the marker of DNA replication 5-bromo-2'-deoxyuridine (BrdU). More recently, various endogenous markers were used to identify young neurons or cycling neuronal progenitors. We review here the respective advantages and pitfalls of these different approaches in birds, with specific reference to the microtubule-associated protein, doublecortin (DCX), that has been extensively used to identify young newly born neurons in adult brains. All these techniques of course have limitations. Exogenous markers label cells replicating their DNA only during a brief period and it is difficult to select injection doses that would exhaustively label all these cells without inducing DNA damage that will also result in some form of labeling during repair. On the other hand, specificity of endogenous markers is difficult to establish due to problems related to the specificity of antibodies (these problems can be, but are not always, addressed) and more importantly because it is difficult, if not impossible, to prove that a given marker exhaustively and specifically labels a given cell population. Despite these potential limitations, these endogenous markers and DCX staining in particular clearly represent a useful approach to the detailed study of neurogenesis especially when combined with other techniques such as BrdU.
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Abstract
OBJECTIVES Mazindol is a sympathomimetic amine, widely used as an anorectic agent in the treatment of obesity. This drug causes psychostimulant effects because of its pharmacological profile similar to amphetamine, acting like a monoamine reuptake inhibitor. However, the mechanisms underlying the action of mazindol are still not clearly understood. METHODS Swiss mice received a single acute administration of mazindol (0.25, 1.25 and 2.5 mg/kg, ip) or saline. After 2 h, the animals were killed by decapitation; the brain was removed and used for the evaluation of activities of mitochondrial respiratory chain complexes, Krebs cycle enzymes and creatine kinase. RESULTS Acute administration of mazindol decreased complex I activity only in the hippocampus. Complex IV activity was increased in the cerebellum (2.5 mg/kg) and cerebral cortex (0.25 mg/kg). Citrate synthase activity was increased in the cerebellum (1.25 mg/kg) and cerebral cortex (1.25 mg/kg), and creatine kinase activity was increased in the cerebellum (1.25 mg/kg). CONCLUSION We suggest that the inhibition of complex I in the hippocampus only and activation of complex IV, citrate synthase and creatine kinase occurs because of a stimulus effect of mazindol in the central nervous system, which causes a direct impairment on energy metabolism.
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Paolone N, Manohar S, Hayes SH, Wong KM, Salvi RJ, Baizer JS. Dissociation of doublecortin expression and neurogenesis in unipolar brush cells in the vestibulocerebellum and dorsal cochlear nucleus of the adult rat. Neuroscience 2014; 265:323-31. [PMID: 24462608 DOI: 10.1016/j.neuroscience.2014.01.026] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2013] [Revised: 01/09/2014] [Accepted: 01/10/2014] [Indexed: 12/27/2022]
Abstract
We have previously shown expression of the protein doublecortin (DCX) in unipolar brush cells (UBCs) in the dorsal cochlear nucleus and vestibulocerebellum of the adult rat. We also saw DCX-immunoreactive elements with the appearance of neuroblasts around the fourth ventricle. Expression of DCX is seen in newborn and migrating neurons and hence considered a correlate of neurogenesis. There were two interpretations of the expression of DCX in UBCs. One possibility is that there might be adult neurogenesis of this cell population. Adult neurogenesis is now well-established, but only for the dentate gyrus of the hippocampus and the subventricular zone. The other possibility is that there is prolonged expression of DCX in adult UBCs that may signal a unique role in plasticity of these neurons. We tested the neurogenesis hypothesis by systemic injections of bromodeoxyuridine (BrdU), a thymidine analog, followed by immunohistochemistry to examine the numbers and locations of dividing cells. We used several different injection paradigms, varying the dose of BrdU, the number of injections and the survival time to assess the possibility of neuronal birth and migration. We saw BrdU-labeled cells in the cerebellum and brainstem; cell division in these regions was confirmed by immunohistochemistry for the protein Ki67. However, neither the numbers nor the distribution of labeled nuclei support the idea of adult neurogenesis and migration of UBCs. The function of DCX expression in UBC's in the adult remains to be understood.
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Affiliation(s)
- N Paolone
- Department of Physiology and Biophysics, School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, NY 14214, USA
| | - S Manohar
- Center for Hearing and Deafness, University at Buffalo, Buffalo, NY 14214, USA
| | - S H Hayes
- Center for Hearing and Deafness, University at Buffalo, Buffalo, NY 14214, USA
| | - K M Wong
- Department of Physiology and Biophysics, School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, NY 14214, USA
| | - R J Salvi
- Center for Hearing and Deafness, University at Buffalo, Buffalo, NY 14214, USA
| | - J S Baizer
- Department of Physiology and Biophysics, School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, NY 14214, USA.
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17
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Microglia: actively surveying and shaping neuronal circuit structure and function. Trends Neurosci 2013; 36:209-17. [DOI: 10.1016/j.tins.2012.11.007] [Citation(s) in RCA: 332] [Impact Index Per Article: 30.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2012] [Revised: 11/16/2012] [Accepted: 11/17/2012] [Indexed: 11/17/2022]
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McEwen BS. The ever-changing brain: cellular and molecular mechanisms for the effects of stressful experiences. Dev Neurobiol 2012; 72:878-90. [PMID: 21898852 DOI: 10.1002/dneu.20968] [Citation(s) in RCA: 107] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The adult brain is capable of considerable structural and functional plasticity and the study of hormone actions in brain has contributed to our understanding of this important phenomenon. In particular, stress and stress-related hormones such as glucocorticoids and mineralocorticoids play a key role in the ability of acute and chronic stress to cause reversible remodeling of neuronal connections in the hippocampus, prefrontal cortex, and amygdala. To produce this plasticity, these hormones act by both genomic and non-genomic mechanisms together with ongoing, experience-driven neural activity mediated by excitatory amino acid neurotransmitters, neurotrophic factors such as brain derived neurotrophic factor, extracellular molecules such as neural cell adhesion molecule, neuropeptides such as corticotrophin releasing factor, and endocannabinoids. The result is a dynamic brain architecture that can be modified by experience. Under this view, the role of pharmaceutical agents, such as antidepressants, is to facilitate such plasticity that must also be guided by experiences.
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Affiliation(s)
- Bruce S McEwen
- Laboratory of Neuroendocrinology, The Rockefeller University, New York, New York 10065, USA.
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Arnold S. Cytochrome c oxidase and its role in neurodegeneration and neuroprotection. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2012; 748:305-39. [PMID: 22729864 DOI: 10.1007/978-1-4614-3573-0_13] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
A hallmark of neurodegenerative diseases, such as Alzheimer's and Parkinson's diseases, and stroke is a malfunction of mitochondria including cytochrome c oxidase (COX), the terminal enzyme complex of the respiratory chain. COX is ascribed a key role based on mainly two regulatory mechanisms. These are the expression of isoforms and the binding of specific allosteric factors to nucleus--encoded subunits. These characteristics represent a unique feature of COX compared with the other respiratory chain complexes. Additional regulatory mechanisms, such as posttranslational modification, substrate availability, and allosteric feedback inhibition by products of the COX reaction, control the enzyme activity in a complex way. In many tissues and cell types, COX represents the rate-limiting enzyme of the respiratory chain which further emphasizes the impact of the regulation of COX as a central site for regulating energy metabolism and oxidative stress. Two of the best-analyzed regulatory mechanisms of COX to date are the allosteric feedback inhibition of the enzyme by its indirect product ATP and the expression of COX subunit IV isoforms. This ATP feedback inhibition of COX requires the expression of COX isoform IV-1. At high ATP/ADP ratios, ADP is exchanged for ATP at the matrix side of COX IV-1 leading to an inhibition of COX activity, thus enabling COX to sense the energy level and to adjust ATP synthesis to energy demand. However, under hypoxic, toxic, and degenerative conditions, COX isoform IV-2 expression is up-regulated and exchanged for COX IV-1 in the enzyme complex. This COX IV isoform switch causes an abolition of the allosteric ATP feedback inhibition of COX and consequently the loss of sensing the energy level. Thus, COX activity is increased leading to higher levels of ATP in neural cells independently of the cellular energy level. Concomitantly, ROS production is increased. Thus, under pathological conditions, neural cells are provided with ATP to meet the energy demand, but at the expense of elevated oxidative stress. This mechanism explains the functional relevance of COX subunit IV isoform expression for cellular energy sensing, ATP production, and oxidative stress levels. This, in turn, affects neural cell function, signaling, and -survival. Thus, COX is a crucial factor in etiology, progression, and prevalence of numerous human neurodegenerative diseases and represents an important target for developing diagnostic and therapeutic tools against those diseases.
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Affiliation(s)
- Susanne Arnold
- Institute for Neuroanatomy, RWTH Aachen University, Wendlingweg 2, Aachen, Germany.
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Expression of doublecortin, a neuronal migration protein, in unipolar brush cells of the vestibulocerebellum and dorsal cochlear nucleus of the adult rat. Neuroscience 2011; 202:169-83. [PMID: 22198017 DOI: 10.1016/j.neuroscience.2011.12.013] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2011] [Revised: 12/11/2011] [Accepted: 12/12/2011] [Indexed: 11/22/2022]
Abstract
Doublecortin (DCX) is a microtubule-associated protein that is critical for neuronal migration and the development of the cerebral cortex. In the adult, it is expressed in newborn neurons in the subventricular and subgranular zones, but not in the mature neurons of the cerebral cortex. By contrast, neurogenesis and neuronal migration of cells in the cerebellum continue into early postnatal life; migration of one class of cerebellar interneuron, unipolar brush cells (UBCs), may continue into adulthood. To explore the possibility of continued neuronal migration in the adult cerebellum, closely spaced sections through the brainstem and cerebellum of adult (3-16 months old) Sprague-Dawley rats were immunolabeled for DCX. Neurons immunoreactive (ir) to DCX were present in the granular cell layer of the vestibulocerebellum, most densely in the transition zone (tz), the region between the flocculus (FL) and ventral paraflocculus (PFL), as well as in the dorsal cochlear nucleus (DCN). These DCX-ir cells had the morphological appearance of UBCs with oval somata and a single dendrite ending in a brush. There were many examples of colocalization of DCX with Eps8 or calretinin, UBC markers. We also identified DCX-ir elements along the fourth ventricle and its lateral recess that had labeled somata but lacked the dendritic structure characteristic of UBCs. Labeled UBCs were seen in nearby white matter. These results suggest that there may be continued neurogenesis and/or migration of UBCs in the adult. Another possibility is that UBCs maintain DCX expression even after migration and maturation, reflecting a role of DCX in adult neuronal plasticity in addition to a developmental role in migration.
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Vicencio JM, Estrada M, Galvis D, Bravo R, Contreras AE, Rotter D, Szabadkai G, Hill JA, Rothermel BA, Jaimovich E, Lavandero S. Anabolic androgenic steroids and intracellular calcium signaling: a mini review on mechanisms and physiological implications. Mini Rev Med Chem 2011; 11:390-8. [PMID: 21443511 DOI: 10.2174/138955711795445880] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2010] [Accepted: 01/21/2011] [Indexed: 02/05/2023]
Abstract
Increasing evidence suggests that nongenomic effects of testosterone and anabolic androgenic steroids (AAS) operate concertedly with genomic effects. Classically, these responses have been viewed as separate and independent processes, primarily because nongenomic responses are faster and appear to be mediated by membrane androgen receptors, whereas long-term genomic effects are mediated through cytosolic androgen receptors regulating transcriptional activity. Numerous studies have demonstrated increases in intracellular Ca2+ in response to AAS. These Ca2+ mediated responses have been seen in a diversity of cell types, including osteoblasts, platelets, skeletal muscle cells, cardiac myocytes and neurons. The versatility of Ca2+ as a second messenger provides these responses with a vast number of pathophysiological implications. In cardiac cells, testosterone elicits voltage-dependent Ca2+ oscillations and IP3R-mediated Ca2+ release from internal stores, leading to activation of MAPK and mTOR signaling that promotes cardiac hypertrophy. In neurons, depending upon concentration, testosterone can provoke either physiological Ca2+ oscillations, essential for synaptic plasticity, or sustained, pathological Ca2+ transients that lead to neuronal apoptosis. We propose therefore, that Ca2+ acts as an important point of crosstalk between nongenomic and genomic AAS signaling, representing a central regulator that bridges these previously thought to be divergent responses.
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Affiliation(s)
- J M Vicencio
- Center for Molecular Studies of the Cell, Faculty of Chemical and Pharmaceutical Sciences/Faculty of Medicine, University of Chile, Santiago, Chile
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Suspension of mitotic activity in dentate gyrus of the hibernating ground squirrel. Neural Plast 2011; 2011:867525. [PMID: 21773054 PMCID: PMC3136081 DOI: 10.1155/2011/867525] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2010] [Revised: 01/05/2011] [Accepted: 03/10/2011] [Indexed: 11/25/2022] Open
Abstract
Neurogenesis occurs in the adult mammalian hippocampus, a region of the brain important for learning and memory. Hibernation in Siberian ground squirrels provides a natural model to study mitosis as the rapid fall in body temperature in 24 h (from 35-36°C to +4–6°C) permits accumulation of mitotic cells at different stages of the cell cycle. Histological methods used to study adult neurogenesis are limited largely to fixed tissue, and the mitotic state elucidated depends on the specific phase of mitosis at the time of day. However, using an immunohistochemical study of doublecortin (DCX) and BrdU-labelled neurons, we demonstrate that the dentate gyrus of the ground squirrel hippocampus contains a population of immature cells which appear to possess mitotic activity. Our data suggest that doublecortin-labelled immature cells exist in a mitotic state and may represent a renewable pool for generation of new neurons within the dentate gyrus.
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Yokose J, Ishizuka T, Yoshida T, Aoki J, Koyanagi Y, Yawo H. Lineage analysis of newly generated neurons in organotypic culture of rat hippocampus. Neurosci Res 2011; 69:223-33. [DOI: 10.1016/j.neures.2010.11.010] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2010] [Revised: 11/08/2010] [Accepted: 11/26/2010] [Indexed: 10/18/2022]
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25
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Stimulated neuronal expression of brain-derived neurotrophic factor by Neurotropin. Mol Cell Neurosci 2010; 45:226-33. [DOI: 10.1016/j.mcn.2010.06.013] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2010] [Revised: 06/02/2010] [Accepted: 06/18/2010] [Indexed: 02/06/2023] Open
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Evaluation of mitochondrial respiratory chain in the brain of rats after pneumococcal meningitis. Brain Res Bull 2010; 82:302-7. [PMID: 20576495 DOI: 10.1016/j.brainresbull.2010.05.012] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2010] [Accepted: 05/20/2010] [Indexed: 01/07/2023]
Abstract
The brain is highly dependent on ATP and most cell energy is obtained through oxidative phosphorylation, a process requiring the action of various respiratory enzyme complexes located in a special structure of the inner mitochondrial membrane. Bacterial meningitis due to Streptococcus pneumoniae is associated with a significant mortality rate and persisting neurologic sequelae including sensory-motor deficits, seizures, and impairments of learning and memory. In this context, we evaluated the activities of mitochondrial respiratory chain complexes in the brain of rats submitted to meningitis by S. pneumoniae inoculation into the cisterna magna. Our results demonstrated that complex I activity was not altered in cerebral cortex after meningitis; complexes II, III and IV were increased 24 and 48h after meningitis. We have also verified that complex I was inhibited in prefrontal cortex 48h after meningitis; complexes II, III and IV were not altered. Our results also demonstrated that complex I activity was inhibited in striatum, hippocampus and cerebellum 24h after meningitis. Moreover, complex II activity was increased in hippocampus and striatum 24 and 48h after meningitis; complexes III and IV activity were increased in striatum, hippocampus and cerebellum 48h after meningitis. Taking together previous reports and our present findings, we speculate that oxidative stress and metabolism impairment might contribute, at least in part, for the pathogenesis of pneumococcal meningitis.
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Cui K, Ashdown H, Luheshi GN, Boksa P. Effects of prenatal immune activation on hippocampal neurogenesis in the rat. Schizophr Res 2009; 113:288-97. [PMID: 19464151 DOI: 10.1016/j.schres.2009.05.003] [Citation(s) in RCA: 99] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/02/2009] [Revised: 05/01/2009] [Accepted: 05/05/2009] [Indexed: 11/18/2022]
Abstract
Maternal infection during pregnancy has been associated with an increased risk for the development of schizophrenia, a disorder characterized by abnormalities in hippocampal morphology and function. Neurogenesis occurs in the hippocampus throughout development into adulthood and is believed to modulate hippocampal function. This study used a rat model in which bacterial endotoxin, lipopolysaccharide (LPS), is administered to pregnant dams, to test if prenatal immune activation has acute and/or long term effects on various phases of neurogenesis (proliferation, survival, differentiation) in the hippocampal dentate gyrus of offspring. When LPS was administered to dams on gestation days (GD) 15 and 16, there was decreased proliferation of dentate cells at postnatal day (PD) 14 and decreased survival of cells generated at PD14 in offspring. When prenatal exposure to LPS was later in pregnancy (GD 18 and 19), offspring showed decreased survival of cells generated both at the time of LPS exposure and at PD14. There was no change in cell proliferation or survival in adult offspring at PD60, with prenatal LPS exposure. Co-administration of the cyclo-oxygenase inhibitor, ibuprofen (IBU), together with prenatal LPS on GD 15 and 16, was unable to prevent the deficit in neuronal survival at PD14. IBU blocked LPS-induced fever but did not block LPS-induced increases in plasma cytokines and corticosterone in the pregnant dam. This indicates that deficits in neurogenesis caused by prenatal LPS are not mediated by LPS-induced fever or eicosanoid induction, but could be mediated by LPS-induced increases in maternal cytokines or corticosterone.
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Affiliation(s)
- Ke Cui
- Department of Psychiatry and of Neurology and Neurosurgery, McGill University, Douglas Mental Health University Institute, Montreal, Quebec, Canada
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28
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Regulation of kainate receptor subunit mRNA by stress and corticosteroids in the rat hippocampus. PLoS One 2009; 4:e4328. [PMID: 19180187 PMCID: PMC2627898 DOI: 10.1371/journal.pone.0004328] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2008] [Accepted: 10/31/2008] [Indexed: 11/19/2022] Open
Abstract
Kainate receptors are a class of ionotropic glutamate receptors that have a role in the modulation of glutamate release and synaptic plasticity in the hippocampal formation. Previous studies have implicated corticosteroids in the regulation of these receptors and recent clinical work has shown that polymorphisms in kainate receptor subunit genes are associated with susceptibility to major depression and response to anti-depressant treatment. In the present study we sought to examine the effects of chronic stress and corticosteroid treatments upon the expression of the mRNA of kainate receptor subunits GluR5-7 and KA1-2. Our results show that, after 7 days, adrenalectomy results in increased expression of hippocampal KA1, GluR6 and GluR7 mRNAs, an effect which is reversed by treatment with corticosterone in the case of KA1 and GluR7 and by aldosterone treatment in the case of GluR6. 21 days of chronic restraint stress (CRS) elevated the expression of the KA1 subunit, but had no effect on the expression of the other subunits. Similarly, 21 days of treatment with a moderate dose of corticosterone also increased KA1 mRNA in the dentate gyrus, whereas a high corticosterone dose has no effect. Our results suggest an interaction between hippocampal kainate receptor composition and the hypothalamic-pituitary-adrenal (HPA) axis and show a selective chronic stress induced modulation of the KA1 subunit in the dentate gyrus and CA3 that has implications for stress-induced adaptive structural plasticity.
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29
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Long J, Liu C, Sun L, Gao H, Liu J. Neuronal Mitochondrial Toxicity of Malondialdehyde: Inhibitory Effects on Respiratory Function and Enzyme Activities in Rat Brain Mitochondria. Neurochem Res 2008; 34:786-94. [DOI: 10.1007/s11064-008-9882-7] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/05/2008] [Indexed: 11/24/2022]
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31
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Choy KHC, van den Buuse M. Attenuated disruption of prepulse inhibition by dopaminergic stimulation after maternal deprivation and adolescent corticosterone treatment in rats. Eur Neuropsychopharmacol 2008; 18:1-13. [PMID: 17490864 DOI: 10.1016/j.euroneuro.2007.03.011] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/18/2006] [Revised: 02/21/2007] [Accepted: 03/29/2007] [Indexed: 10/23/2022]
Abstract
The development of schizophrenia may include an early neurodevelopmental stress component which increases vulnerability to later stressful life events, in combination leading to overt disease. We investigated the effect of an early stress, in the form of maternal deprivation, combined with a later stress, simulated by chronic periadolescent corticosterone treatment, on behaviour in rats. Acute treatment with apomorphine caused disruption of prepulse inhibition (PPI) in controls and in rats that had undergone either maternal deprivation or corticosterone treatment, but was surprisingly absent in rats that had undergone the combined early and late stress. Amphetamine treatment significantly disrupted PPI in both non-deprived groups, but was absent in both maternally deprived groups. The serotonin-1A receptor agonist, 8-OH-DPAT, induced a significant disruption of PPI in all groups. Amphetamine-induced locomotor hyperactivity was similar in all groups. These results show an inhibitory interaction of early stress, caused by maternal deprivation, combined with 'adolescent' stress, simulated by corticosterone treatment, on dopaminergic regulation of PPI. The altered effects of apomorphine and amphetamine could indicate differential changes in dopamine receptor signalling leading to functional desensitisation, or altered modulation of sensory gating in the nucleus accumbens by limbic structures such as the hippocampus.
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Affiliation(s)
- Kwok Ho Christopher Choy
- Behavioural Neuroscience Laboratory, Mental Health Research Institute of Victoria, 155 Oak Street, Parkville, Victoria 3052, Australia
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32
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Pucak ML, Carroll KAL, Kerr DA, Kaplin AI. Neuropsychiatric manifestations of depression in multiple sclerosis: neuroinflammatory, neuroendocrine, and neurotrophic mechanisms in the pathogenesis of immune-mediated depression. DIALOGUES IN CLINICAL NEUROSCIENCE 2007. [PMID: 17726912 PMCID: PMC3181849 DOI: 10.31887/dcns.2007.9.2/mpucak] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Evidence suggests that depression in multiple sclerosis (MS) is largely biologically mediated by some of the same processes involved in the immunopathogenesis of this neurologic disease. In particular, the increase in proinflammatory cytokines, activation of the hypothalamic-pituitary-adrenal (HPA) axis, and reduction in neurotrophic factors that occur in MS may each account for the increased rate of depression seen in MS. The possible contributions of these neuroinflammatory, neuroendocrine, and neurotrophic mechanisms suggest a diverse array of novel treatment strategies for depression, both in the context of inflammatory conditions as well as in idiopathic depression. Furthermore, if such processes in MS play a causative role in the pathogenesis of depression, and depression in turn has affects on neurophysiological processes related to immune function, then treatment of depression might have a positive effect on MS disease progression. This makes treating MS depression a neuropsychiatric imperative.
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Affiliation(s)
- Michele L Pucak
- Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, Baltimore, Maryland 21287, USA
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33
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Choi YS, Cho KO, Kim SY. Asymmetry in enhanced neurogenesis in the rostral dentate gyrus following kainic acid-induced status epilepticus in adult rats. Arch Pharm Res 2007; 30:646-52. [PMID: 17615686 DOI: 10.1007/bf02977661] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Neurogenesis in the suprapyramidal and infrapyramidal blades of the rostral dentate gyrus was investigated following kainic acid (KA)-induced status epilepticus (SE) in adult rats. Rats were injected with KA (14 mg/kg, i.p.) or saline, with convulsions terminated by an intraperitoneal injection of diazepam. Five days after the induction of SE, the rats were injected with 5-bromo-2-deoxyuridine-5-monophosphate (BrdU; 75 mg/kg, i.p.), a marker of cell division. One day after the BrdU injection, the numbers of BrdU-labeled cells in the supra- and infrapyramidal blades were significantly higher in the KA-injected rats compared to the saline-injected rats. In the saline-injected rats, the number of BrdU-labeled cells in the infrapyramidal blade was greater than in the suprapyramidal blade. Twenty-eight days after the BrdU injection, the number of BrdU-labeled cells remained significantly higher in the KA-injected rats than the saline-injected rats, but only in the infrapyramidal blade. In addition, when the extent of cell death was examined with Fluoro-Jade B (a marker of dead and dying cells) 3 days after the induction of SE, degenerating cells were more numerous in the infrapyramidal blade than in the suprapyramidal blade. Our results suggest that there is an asymmetry of neurogenesis and cell death in the rostral dentate gyrus of rats following KA-induced SE.
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Affiliation(s)
- Yun-Sik Choi
- Department of Pharmacology, The Catholic University of Korea, Seoul 137-701, Korea
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Veenema AH, de Kloet ER, de Wilde MC, Roelofs AJ, Kawata M, Buwalda B, Neumann ID, Koolhaas JM, Lucassen PJ. Differential effects of stress on adult hippocampal cell proliferation in low and high aggressive mice. J Neuroendocrinol 2007; 19:489-98. [PMID: 17561881 DOI: 10.1111/j.1365-2826.2007.01555.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Male wild house mice selected for a long (LAL) or a short (SAL) latency to attack a male intruder generally show opposing behavioural coping responses to environmental challenges. LAL mice, unlike SAL mice, adapt to novel challenges with a highly reactive hypothalamic-pituitary-adrenal axis and show an enhanced expression of markers for hippocampal plasticity. The present study aimed to test the hypothesis that these features of the more reactive LAL mice are reflected in parameters of hippocampal cell proliferation. The data show that basal cell proliferation in the subgranular zone (SGZ) of the dentate gyrus, assessed by the endogenous proliferation marker Ki-67, is lower in LAL than in SAL mice. Furthermore, application of bromodeoxyuridine (BrdU) over 3 days showed an almost two-fold lower cell proliferation rate in the SGZ in LAL versus SAL mice. Exposure to forced swimming resulted, 24 h later, in a significant reduction in BrdU + cell numbers in LAL mice, whereas cell proliferation was unaffected by this stressor in SAL mice. Plasma corticosterone and dentate gyrus glucocorticoid receptor levels were higher in LAL than in SAL mice. However, no differences between the SAL and LAL lines were found for hippocampal NMDA receptor binding. In conclusion, the data suggest a relationship between coping responses and hippocampal cell proliferation, in which corticosterone may be one of the determinants of line differences in cell proliferation responses to environmental challenges.
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Affiliation(s)
- A H Veenema
- Department of Behavioural Physiology, Center for Behavioural and Cognitive Neuroscience, University of Groningen, The Netherlands.
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Abstract
Since the discovery of nerve growth factor (NGF) in the 1950s and brain-derived neurotrophic factor (BDNF) in the 1980s, a great deal of evidence has mounted for the roles of neurotrophins (NGF; BDNF; neurotrophin-3, NT-3; and neurotrophin-4/5, NT-4/5) in development, physiology, and pathology. BDNF in particular has important roles in neural development and cell survival, as well as appearing essential to molecular mechanisms of synaptic plasticity and larger scale structural rearrangements of axons and dendrites. Basic activity-related changes in the central nervous system (CNS) are thought to depend on BDNF modulation of synaptic transmission. Pathologic levels of BDNF-dependent synaptic plasticity may contribute to conditions such as epilepsy and chronic pain sensitization, whereas application of the trophic properties of BDNF may lead to novel therapeutic options in neurodegenerative diseases and perhaps even in neuropsychiatric disorders. In this chapter, I review neurotrophin structure, signal transduction mechanisms, localization and regulation within the nervous system, and various potential roles in disease. Modulation of neurotrophin action holds significant potential for novel therapies for a variety of neurological and psychiatric disorders.
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Affiliation(s)
- Devin K Binder
- Department of Neurological Surgery, University of California, Irvine, CA 92868, USA.
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Parent JM. Adult neurogenesis in the intact and epileptic dentate gyrus. PROGRESS IN BRAIN RESEARCH 2007; 163:529-40. [PMID: 17765736 DOI: 10.1016/s0079-6123(07)63028-3] [Citation(s) in RCA: 141] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Neurogenesis persists throughout life in the adult mammalian dentate gyrus. Adult-born dentate granule cells integrate into existing hippocampal circuitry and may provide network plasticity necessary for certain forms of hippocampus-dependent learning and memory. Neural stem cells and neurogenesis in the adult dentate gyrus are regulated by a variety of environmental, physiological, and molecular factors. These include aging, stress, exercise, neurovascular components of the stem cell niche, growth factors, neurotransmitters, and hormones. Seizure activity also influences dentate granule cell neurogenesis. Production of adult-born neurons increases in rodent models of temporal lobe epilepsy, and both newborn and pre-existing granule neurons contribute to aberrant axonal reorganization in the epileptic hippocampus. Prolonged seizures also disrupt the migration of dentate granule cell progenitors and lead to hilar-ectopic granule cells. The ectopic granule neurons appear to integrate abnormally and contribute to network hyperexcitability. Similar findings of granule cell layer dispersion and ectopic granule neurons in human TLE suggest that aberrant neurogenesis contributes to epileptogenesis or learning and memory disturbances in this epilepsy syndrome.
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Affiliation(s)
- Jack M Parent
- Department of Neurology, University of Michigan Medical Center, Ann Arbor, MI 48109-2200, USA.
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Navarro A, Boveris A. The mitochondrial energy transduction system and the aging process. Am J Physiol Cell Physiol 2006; 292:C670-86. [PMID: 17020935 DOI: 10.1152/ajpcell.00213.2006] [Citation(s) in RCA: 476] [Impact Index Per Article: 26.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Aged mammalian tissues show a decreased capacity to produce ATP by oxidative phosphorylation due to dysfunctional mitochondria. The mitochondrial content of rat brain and liver is not reduced in aging and the impairment of mitochondrial function is due to decreased rates of electron transfer by the selectively diminished activities of complexes I and IV. Inner membrane H(+) impermeability and F(1)-ATP synthase activity are only slightly affected by aging. Dysfunctional mitochondria in aged rodents are characterized, besides decreased electron transfer and O(2) uptake, by an increased content of oxidation products of phospholipids, proteins and DNA, a decreased membrane potential, and increased size and fragility. Free radical-mediated oxidations are determining factors of mitochondrial dysfunction and turnover, cell apoptosis, tissue function, and lifespan. Inner membrane enzyme activities, such as those of complexes I and IV and mitochondrial nitric oxide synthase, decrease upon aging and afford aging markers. The activities of these three enzymes in mice brain are linearly correlated with neurological performance, as determined by the tightrope and the T-maze tests. The same enzymatic activities correlated positively with mice survival and negatively with the mitochondrial content of lipid and protein oxidation products. Conditions that increase survival, as vitamin E dietary supplementation, caloric restriction, high spontaneous neurological activity, and moderate physical exercise, ameliorate mitochondrial dysfunction in aged brain and liver. The pleiotropic signaling of mitochondrial H(2)O(2) and nitric oxide diffusion to the cytosol seems modified in aged animals and to contribute to the decreased mitochondrial biogenesis in old animals.
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Affiliation(s)
- Ana Navarro
- Departamento de Bioquímica y Biología Molecular, Facultad de Medicina, Plaza Fragela 9, 11003 Cádiz, Spain.
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Porter RJ, Gallagher P. Abnormalities of the HPA axis in affective disorders: clinical subtypes and potential treatments. Acta Neuropsychiatr 2006; 18:193-209. [PMID: 26989919 DOI: 10.1111/j.1601-5215.2006.00152.x] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND New evidence is emerging regarding abnormalities of hypothalamic-pituitary-adrenal (HPA) axis function in subtypes of affective disorders. Adverse effects of HPA axis dysregulation may include dysfunction of monoaminergic transmitter systems, cognitive impairment and peripheral effects. Newer treatments specifically targeting the HPA axis are being developed. OBJECTIVE To review these developments focusing particularly on the glucocorticoid receptor (GR) antagonist mifepristone. METHOD A selective review of the literature. RESULTS The function of GRs is increasingly being defined. The role of corticotrophin-releasing hormone (CRH) and dehydroepiandrosterone (DHEA) in the brain is also increasingly understood. HPA axis function is particularly likely to be abnormal in psychotic depression and bipolar disorder, and it is in these conditions that trials of the GR antagonist mifepristone are being focused. CRH antagonists and DHEA are also being investigated as potential treatments. CONCLUSION Initial studies of mifepristone and other HPA-axis-targeting agents in psychotic depression and bipolar disorder are encouraging and confirmatory studies are awaited.
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Affiliation(s)
- Richard J Porter
- 1Department of Psychological Medicine, Christchurch School of Medicine and Health Sciences, Christchurch, New Zealand
| | - Peter Gallagher
- 2School of Neurology, Neurobiology and Psychiatry, University of Newcastle, Newcastle upon Tyne, UK
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Silva R, Lu J, Wu Y, Martins L, Almeida OFX, Sousa N. Mapping cellular gains and losses in the postnatal dentate gyrus: Implications for psychiatric disorders. Exp Neurol 2006; 200:321-31. [PMID: 16624303 DOI: 10.1016/j.expneurol.2006.02.119] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2005] [Revised: 01/13/2006] [Accepted: 02/20/2006] [Indexed: 10/24/2022]
Abstract
Neurogenesis and apoptosis occur contemporaneously in the postnatal hippocampal dentate gyrus and have been implicated in mood and cognitive disorders. Particularly, neurogenesis correlates with the manifestation of antidepressant effects, but its quantitative and topographical relationship with concomitant cell death has not been investigated. Accordingly, we applied stereological measurements to obtain synchronized topographical maps of these two events in rats aged 1 and 3 months under basal conditions; the two ages were chosen to represent neuro-developmental windows during which cell proliferation and death are occurring at peak and relatively steady levels, respectively. Our analysis shows that apoptotic cells are evenly distributed throughout the dentate gyrus, although the incidence of apoptosis decreased gradient-wise from the tip of the suprapyramidal layer and was highest in the external third of the granule cell layer. Interestingly, apoptosis was higher in the left hippocampus. In addition, we confirm previous less stringent studies demonstrating that neurogenesis occurs differentially in the dorsal-ventral axis of the hippocampus and in suprapyramidal-infrapyramidal blades of the dentate gyrus. These results raise intriguing new questions regarding the coordinated regulation of hippocampal neurogenesis and apoptosis since the two processes apparently share common regulatory factors. In addition, these findings open questions with respect to the functional significance of topographical gradients in neurogenesis and apoptosis in the context of the etiopathogenesis of neuropsychiatric diseases and the reported dependence on the efficacy of therapeutic agents on the generation of new hippocampal neurons.
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Affiliation(s)
- Rui Silva
- Neuroscience Group, Life and Health Sciences Research Institute, ICVS, University of Minho, 4710-057 Braga, Portugal
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40
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Estrada M, Varshney A, Ehrlich BE. Elevated testosterone induces apoptosis in neuronal cells. J Biol Chem 2006; 281:25492-501. [PMID: 16803879 DOI: 10.1074/jbc.m603193200] [Citation(s) in RCA: 120] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
Testosterone plays a crucial role in neuronal function, but elevated concentrations can have deleterious effects. Here we show that supraphysiological levels of testosterone (micromolar range) initiate the apoptotic cascade. We used three criteria, annexin V labeling, caspase activity, and DNA fragmentation, to determine that apoptotic pathways were activated by testosterone. Micromolar, but not nanomolar, testosterone concentrations increased the response in all three assays of apoptosis. In addition, testosterone induced different concentration-dependent Ca2+ signaling patterns: at low concentrations of testosterone (100 nm), Ca2+ oscillations were produced, whereas high concentrations (1-10 microm) induced a sustained Ca2+ increase. Elevated testosterone concentrations increase cell death, and this effect was abolished in the presence of either inhibitors of caspases or the inositol 1,4,5-trisphosphate receptor (InsP3R)-mediated Ca2+ release. Knockdown of InsP3R type 1 with specific small interfering RNA also abolished the testosterone-induced cell death and the prolonged Ca2+ signals. In contrast, knockdown of InsP3R type 3 modified neither the apoptotic response nor the Ca2+ signals. These results support our hypothesis that elevated testosterone alters InsP3R type 1-mediated intracellular Ca2+ signaling and that the prolonged Ca2+ signals lead to apoptotic cell death. These effects of testosterone on neurons will have long term effects on brain function.
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Affiliation(s)
- Manuel Estrada
- Department of Pharmacology and Cellular and Molecular Physiology, Yale University, New Haven, Connecticut 06520,
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41
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McCaffery P, Deutsch CK. Macrocephaly and the control of brain growth in autistic disorders. Prog Neurobiol 2005; 77:38-56. [PMID: 16280193 DOI: 10.1016/j.pneurobio.2005.10.005] [Citation(s) in RCA: 75] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2005] [Revised: 09/29/2005] [Accepted: 10/05/2005] [Indexed: 01/17/2023]
Abstract
Autism is a childhood-onset neuropsychiatric disorder characterized by marked impairments in social interactions and communication, with restricted stereotypic and repetitive patterns of behavior, interests, and activities. Genetic epidemiology studies indicate that a strong genetic component exists to this disease, but these same studies also implicate significant environmental influence. The disorder also displays symptomatologic heterogeneity, with broad individual differences and severity on a graded continuum. In the search for phenotypes to resolve heterogeneity and better grasp autism's underlying biology, investigators have noted a statistical overrepresentation of macrocephaly, an indicator of enlarged brain volume. This feature is one of the most widely replicated biological findings in autism. What then does brain enlargement signify? One hypothesis invoked for the origin of macrocephaly is a reduction in neuronal pruning and consolidation of synapses during development resulting in an overabundance of neurites. An increase in generation of cells is an additional mechanism for macrocephaly, though it is less frequently discussed in the literature. Here, we review neurodevelopmental mechanisms regulating brain growth and highlight one underconsidered potential causal mechanism for autism and macrocephaly--an increase in neurogenesis and/or gliogenesis. We review factors known to control these processes with an emphasis on nuclear receptor activation as one signaling control that may be abnormal and contribute to increased brain volume in autistic disorders.
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Mayer D, Fischer H, Schneider U, Heimrich B, Schwemmle M. Borna disease virus replication in organotypic hippocampal slice cultures from rats results in selective damage of dentate granule cells. J Virol 2005; 79:11716-23. [PMID: 16140749 PMCID: PMC1212617 DOI: 10.1128/jvi.79.18.11716-11723.2005] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
In the hippocampus of Borna disease virus (BDV)-infected newborn rats, dentate granule cells undergo progressive cell death. BDV is noncytolytic, and the pathogenesis of this neurodevelopmental damage in the absence of immunopathology remains unclear. A suitable model system to study early events of the pathology is lacking. We show here that organotypic hippocampal slice cultures from newborn rat pups are a suitable ex vivo model to examine BDV neuropathogenesis. After challenging hippocampal slice cultures with BDV, we observed a progressive loss of calbindin-positive granule cells 21 to 28 days postinfection. This loss was accompanied by reduced numbers of mossy fiber boutons when compared to mock-infected cultures. Similarly, the density of dentate granule cell axons, the mossy fiber axons, appeared to be substantially reduced. In contrast, hilar mossy cells and pyramidal neurons survived, although BDV was detectable in these cells. Despite infection of dentate granule cells 2 weeks postinfection, the axonal projections of these cells and the synaptic connectivity patterns were comparable to those in mock-infected cultures, suggesting that BDV-induced damage of granule cells is a post-maturation event that starts after mossy fiber synapses are formed. In summary, we find that BDV infection of rat organotypic hippocampal slice cultures results in selective neuronal damage similar to that observed with infected newborn rats and is therefore a suitable model to study BDV-induced pathology in the hippocampus.
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Affiliation(s)
- Daniel Mayer
- Department of Virology, Institute for Medical Microbiology and Hygiene, University of Freiburg, Hermann-Herder-Strasse 11, D-79104 Freiburg, Germany
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Hayley S, Poulter MO, Merali Z, Anisman H. The pathogenesis of clinical depression: stressor- and cytokine-induced alterations of neuroplasticity. Neuroscience 2005; 135:659-78. [PMID: 16154288 DOI: 10.1016/j.neuroscience.2005.03.051] [Citation(s) in RCA: 232] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2004] [Revised: 03/11/2005] [Accepted: 03/22/2005] [Indexed: 11/18/2022]
Abstract
Stressful events promote neurochemical changes that may be involved in the provocation of depressive disorder. In addition to neuroendocrine substrates (e.g. corticotropin releasing hormone, and corticoids) and central neurotransmitters (serotonin and GABA), alterations of neuronal plasticity or even neuronal survival may play a role in depression. Indeed, depression and chronic stressor exposure typically reduce levels of growth factors, including brain-derived neurotrophic factor and anti-apoptotic factors (e.g. bcl-2), as well as impair processes of neuronal branching and neurogenesis. Although such effects may result from elevated corticoids, they may also stem from activation of the inflammatory immune system, particularly the immune signaling cytokines. In fact, several proinflammatory cytokines, such as interleukin-1, tumor necrosis factor-alpha and interferon-gamma, influence neuronal functioning through processes involving apoptosis, excitotoxicity, oxidative stress and metabolic derangement. Support for the involvement of cytokines in depression comes from studies showing their elevation in severe depressive illness and following stressor exposure, and that cytokine immunotherapy (e.g. interferon-alpha) elicited depressive symptoms that were amenable to antidepressant treatment. It is suggested that stressors and cytokines share a common ability to impair neuronal plasticity and at the same time altering neurotransmission, ultimately contributing to depression. Thus, depressive illness may be considered a disorder of neuroplasticity as well as one of neurochemical imbalances, and cytokines may act as mediators of both aspects of this illness.
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Affiliation(s)
- S Hayley
- Institute of Neuroscience, Carleton University, 1125 Colonel By Drive, Ottawa, Ontario, Canada K1S 5B6.
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Scorza FA, Guerra ADBG, Cavalheiro EA, Calil HM. Neurogênese e depressão: etiologia ou nova ilusão? BRAZILIAN JOURNAL OF PSYCHIATRY 2005; 27:249-53. [PMID: 16224616 DOI: 10.1590/s1516-44462005000300017] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Novos neurônios continuam sendo gerados no cérebro adulto de diversas espécies animais. Muitos estudos têm demonstrado que diversos fatores ambientais, inclusive o estresse, influenciam a proliferação de células hipocampais. Nesse sentido, a diminuição da neurogênese induzida pelo estresse parece ser um importante fator na etiologia da depressão. Nessa revisão, a relação entre neurogênese e depressão é enfatizada.
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Crespel A, Rigau V, Coubes P, Rousset MC, de Bock F, Okano H, Baldy-Moulinier M, Bockaert J, Lerner-Natoli M. Increased number of neural progenitors in human temporal lobe epilepsy. Neurobiol Dis 2005; 19:436-50. [PMID: 16023586 DOI: 10.1016/j.nbd.2005.01.020] [Citation(s) in RCA: 108] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2004] [Revised: 12/18/2004] [Accepted: 01/20/2005] [Indexed: 10/25/2022] Open
Abstract
An increased neurogenesis is reported in animal models of mesial temporal lobe epilepsy (MTLE) but the fate of newborn cells is unknown. Here, we attempted to demonstrate neurogenesis in adult epileptic tissue obtained after hippocampectomy. MTLE hippocampi showed increased expression of division markers and of Musashi-1, a marker of neural progenitors, compared to control hippocampi. Large quantities of Musashi-1+ cells were obvious in the subgranular layer and the subventricular zone, both known neurogenic areas, and in the fissura hippocampi. Musashi-1 was expressed by small cells that were mainly vimentin+ or nestin+, rarely Dcx+ or PSA-NCAM+ and negative for markers of mature neurons or astrocytes. Some of them are present in the granular layer, the hilus, and CA1 area resembling the ectopic positions described in rodents. These findings demonstrate that neural progenitors proliferate in chronic epilepsy and suggest that the fissura hippocampi behaves like another neurogenic area.
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Affiliation(s)
- Arielle Crespel
- Institut de Génomique Fonctionnelle, CNRS UMR 5023-INSERM U661, UM1-UM2, 141 rue de la Cardonille, F-34094 Montpellier Cedex 5, France
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Naylor AS, Persson AI, Eriksson PS, Jonsdottir IH, Thorlin T. Extended Voluntary Running Inhibits Exercise-Induced Adult Hippocampal Progenitor Proliferation in the Spontaneously Hypertensive Rat. J Neurophysiol 2005; 93:2406-14. [PMID: 15615829 DOI: 10.1152/jn.01085.2004] [Citation(s) in RCA: 97] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Previous work has shown that voluntary running increases cell proliferation and neurogenesis in the dentate gyrus of the adult hippocampus. Here we report that long-term running for 24 days results in a down-regulation of hippocampal progenitor proliferation to one-half the level of nonrunning controls compared with a fivefold increase in progenitor proliferation seen after 9 days of voluntary running (short-term running). The negative effects seen on proliferation after 24 days of running were prevented by restricting daily running distances (by 30–50%) during 24 days. Long-term running for 24 days increases the response of the hypothalamic-pituitary-adrenal axis, with an increase in adrenal gland weight and increased plasma corticosterone levels, as well as decreased thymus weight, indicating a stress response as a possible mediator of decreased progenitor proliferation. Furthermore, the negative effects seen on the observed stress response after 24 days of running were prevented by restricting daily running distance. Short-term running did not alter these stress parameters compared with nonrunning controls. However, it increased phosphorylated cyclic AMP response element binding protein (pCREB) in the dentate gyrus, an increase that was not seen in nonrunning controls or after 24 days of running. Taken together, these data suggest that voluntary running does not always enhance proliferation and that the decrease in progenitor proliferation seen in long-term running is possibly mediated by mechanisms involving a stress response in the animal. However, a moderate level of long-term running was able to prevent the negative stress-related changes seen in unrestricted long-term running.
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Affiliation(s)
- Andrew S Naylor
- Department of Physiology, Sahlgrenska Academy, Box 432, 405 30 Göteborg, Sweden.
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Zhang M, Hung FS, Zhu Y, Xie Z, Wang JH. Calcium signal-dependent plasticity of neuronal excitability developed postnatally. ACTA ACUST UNITED AC 2005; 61:277-87. [PMID: 15382030 DOI: 10.1002/neu.20045] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Neuronal plasticity and its development were investigated at pyramidal neurons in the cortical slices of rats. The threshold and probability of firing spikes were measured by using whole-cell recording to assess neuronal excitability. Postsynaptic high frequency activity (HFA) at the pyramidal neurons, evoked by 20 trains (250-ms interval) of five depolarization-pulses (1 ms) at 100 Hz, persistently lowered the threshold and increased the probability of firing spikes. After long-term enhancement of neuronal excitability by HFA was stable, another HFA induced further enhancement. Infusing 1 mM 1,2-bis(2-aminophenoxy)-ethane-N, N,N',N'-tetraacetic acid or 100 microM CaMKII(281-301) into the recording neurons prevented HFA-induced long-term enhancement of neuronal excitability. The infusion of 40 microM calcineurin autoinhibitory peptide enhanced neuronal excitability, which occluded HFA effect. HFA-induced long-term enhancement of intrinsic excitability expressed at most pyramidal neurons after postnatal day (PND) 14, but not at those before PND 9. Our results show a new type of neuronal plasticity induced by physiological activity at cortical neurons, which requires calcium-dependent protein phosphorylation and develops during postnatal period. An upregulation of intrinsic excitability at cortical neurons facilitates their activity and broadens signal codes; consequently, their computational ability is upgraded.
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Affiliation(s)
- Mei Zhang
- Department of Molecular Biosciences, University of Kansas, Lawrence, Kansas 66045, USA
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48
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Abstract
Research into neurogenesis, i.e., the growth of new neurons in the adult brain, is leaving the area of pure basic science and gaining relevance for clinical disciplines such as psychopharmacology and molecular psychiatry. Neurogenesis is proposed to play a crucial role in psychiatric disorders which exhibit degenerative alterations, neural maldevelopment, and changes in neural plasticity as potentially important pathophysiological factors. Especially in dementia, drug addiction, and schizophrenic and affective psychoses, disruption of adult neurogenesis could thus represent a considerable pathogenetic element. Interestingly, several psychotropic drugs (e.g., antidepressants, atypical antipsychotics) are able to modify neurogenesis significantly. Further elucidation of the importance and implications of neurogenesis may concomitantly result in better understanding of the etiopathogenesis of mental disorders and increased knowledge of the mechanisms of action of psychotropic substances. Furthermore, this may support the development of promising innovative therapeutic approaches in clinical practice.
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Affiliation(s)
- J Thome
- Department of Psychiatry, School of Medicine, University of Wales Swansea, UK.
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Joëls M, Karst H, Alfarez D, Heine VM, Qin Y, van Riel E, Verkuyl M, Lucassen PJ, Krugers HJ. Effects of chronic stress on structure and cell function in rat hippocampus and hypothalamus. Stress 2004; 7:221-31. [PMID: 16019587 DOI: 10.1080/10253890500070005] [Citation(s) in RCA: 217] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/23/2022] Open
Abstract
It has become increasingly clear that the increase in corticosteroid levels, e.g. after a brief stressor induce molecular and cellular changes in brain, including the hippocampal formation. These effects eventually result in behavioral adaptation. Prolonged exposure to stress, though, may lead to mal-adaptation and even be a risk factor for diseases like major depression in genetically predisposed individuals. We conducted a series of experiments where changes in brain function were examined after 3 weeks of unpredictable stress. After unpredictable stress, inhibitory input to neurons involved in the hypothalamus-pituitary-adrenal (HPA) axis regulation was suppressed, which may dysregulate the axis and lead to overexposure of the brain to glucocorticoids. Furthermore, glutamate transmission in the dentate gyrus (DG) was enhanced, possibly through transcriptional regulation of receptor subunits. Combined with enhanced calcium channel expression this could increase vulnerability to cell death. Neurogenesis and apoptosis in the dentate were diminished. Synaptic plasticity was suppressed both in the dentate and CA1 area. Collectively, these effects may give rise to deficits in memory formation. Finally, we observed reduced responses to serotonin in the CA1 area, which could contribute to the onset of symptoms of depression in predisposed individuals. All of these endpoints provide potential targets for novel treatment strategies of stress-related brain disorders.
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Affiliation(s)
- Marian Joëls
- SILS-CNS, University of Amsterdam, The Netherlands.
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50
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Datson NA, Meijer L, Steenbergen PJ, Morsink MC, van der Laan S, Meijer OC, de Kloet ER. Expression profiling in laser-microdissected hippocampal subregions in rat brain reveals large subregion-specific differences in expression. Eur J Neurosci 2004; 20:2541-54. [PMID: 15548198 DOI: 10.1111/j.1460-9568.2004.03738.x] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Expression profiling in the hippocampus is hampered by its cellular heterogeneity. The aim of this study was to evaluate the feasibility of using laser-microdissected hippocampal subregions for expression profiling to improve detection of transcripts with a subregion-specific expression. Cornu ammonis (CA)3 and dentate gyrus (DG) subregions were isolated from rat brain slices using laser microdissection, subjected to two rounds of linear amplification and hybridized to rat GeneChips containing approximately 8000 transcripts (RG_U34A; Affymetrix). Analysis of the data using significance analysis of microarrays revealed 724 genes with a significant difference in expression between CA3 and DG with a false discovery rate of 2.1%, of which 264 had higher expression in DG and 460 in CA3. Several transcripts with known differential expression between the subregions were included in the dataset, as well as numerous novel mRNAs and expressed sequence tags. Sorting of the differentially expressed genes according to gene ontology classification revealed that genes involved in glycolysis and general metabolism, neurogenesis and cell adhesion were consistently expressed at higher levels in CA3. Conversely, a large cluster of genes involved in protein biosynthesis were expressed at higher levels in DG. In situ hybridization was used to validate differential expression of a selection of genes. The results of this study demonstrate that the combination of laser microdissection and GeneChip technology is both technically feasible and very promising. Besides providing an extensive inventory of genes showing differential expression between CA3 and DG, this study supports the idea that profiling in hippocampal subregions should improve detection of genes with a subregion-specific expression or regulation.
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Affiliation(s)
- N A Datson
- Division of Medical Pharmacology, Leiden/Amsterdam Center for Drug Research, Leiden, The Netherlands.
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