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Buffenstein R, Pinto M. Endocrine function in naturally long-living small mammals. Mol Cell Endocrinol 2009; 299:101-11. [PMID: 18674586 PMCID: PMC4399555 DOI: 10.1016/j.mce.2008.04.021] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/10/2008] [Accepted: 04/11/2008] [Indexed: 12/19/2022]
Abstract
The complex, highly integrative endocrine system regulates all aspects of somatic maintenance and reproduction and has been widely implicated as an important determinant of longevity in short-lived traditional model organisms of aging research. Genetic or experimental manipulation of hormone profiles in mice has been proven to definitively alter longevity. These hormonally induced lifespan extension mechanisms may not necessarily be relevant to humans and other long-lived organisms that naturally show successful slow aging. Long-lived species may have evolved novel anti-aging defenses germane to naturally retarding the aging process. Here, we examine the available endocrine data associated with the vitamin D, insulin, glucocorticoid and thyroid endocrine systems of naturally long-living small mammals. Generally, long-living rodents and bats maintain tightly regulated lower basal levels of these key pleiotropic hormones than shorter lived rodents. Similarities with genetically manipulated long-lived rodent models of aging suggest that evolutionary well-conserved hormonal mechanisms are integrally involved in lifespan determination.
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Affiliation(s)
- Rochelle Buffenstein
- The Sam and Ann Barshop Institute for Longevity and Aging Studies & Department of Physiology, University of Texas Health Science Center at San Antonio, TX 78245, United States.
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Abstract
Growing evidence indicates that physical and psychosocial stressors, in part acting through the hypothalamic-pituitary-adrenal (HPA) axis, may accelerate the process of Alzheimer's disease (AD). In this review, we summarize recent research related to the effects of stress and stress hormones on the various disease process elements associated with AD. Specifically, we focus on the relationships among chronic stressors, HPA axis activity, amyloid-beta protein, and amyloid-beta plaque deposition in mouse models of AD. The potential mechanisms by which stress and stress-related components, especially corticotrophin-releasing factor and its receptors, influence the pathogenesis of AD are discussed.
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Affiliation(s)
- Hongxin Dong
- Department of Psychiatry and Behavioral Sciences, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA.
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53
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Dong H, Yuede CM, Yoo HS, Martin MV, Deal C, Mace AG, Csernansky JG. Corticosterone and related receptor expression are associated with increased beta-amyloid plaques in isolated Tg2576 mice. Neuroscience 2008; 155:154-63. [PMID: 18571864 PMCID: PMC2664643 DOI: 10.1016/j.neuroscience.2008.05.017] [Citation(s) in RCA: 91] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2008] [Revised: 05/09/2008] [Accepted: 05/13/2008] [Indexed: 11/19/2022]
Abstract
Previously, we reported that the stress associated with chronic isolation was associated with increased beta-amyloid (Abeta) plaque deposition and memory deficits in the Tg2576 transgenic animal model of Alzheimer's disease (AD) [Dong H, Goico B, Martin M, Csernansky CA, Bertchume A, Csernansky JG (2004) Effects of isolation stress on hippocampal neurogenesis, memory, and amyloid plaque deposition in APP (Tg2576) mutant mice. Neuroscience 127:601-609]. In this study, we investigated the potential mechanisms of stress-accelerated Abeta plaque deposition in this Tg2576 mice by examining the relationship between plasma corticosterone levels, expression of glucocorticoid receptor (GR) and corticotropin-releasing factor receptor-1 (CRFR1) in the brain, brain tissue Abeta levels and Abeta plaque deposition during isolation or group housing from weaning (i.e. 3 weeks of age) until 27 weeks of age. We found that isolation housing significantly increased plasma corticosterone levels as compared with group-housing in both Tg+ mice (which contain and overexpress human amyloid precursor protein (hAPP) gene) and Tg- mice (which do not contain hAPP gene as control). Also, isolated, but not group-housed animals showed increases in the expression of GR in the cortex. Furthermore, the expression of CRFR1 was increased in isolated Tg+ mice, but decreased in isolated Tg- mice in both cortex and hippocampus. Changes in the components of hypothalamic-pituitary-adrenal (HPA) axis were accompanied by increases in brain tissue Abeta levels and Abeta plaque deposition in the hippocampus and overlying cortex in isolated Tg+ mice. These results suggest that isolation stress increases corticosterone levels and GR and CRFR1 expression in conjunction with increases in brain tissue Abeta levels and Abeta plaque deposition in the Tg2576 mouse model of AD.
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MESH Headings
- Amyloid beta-Peptides/metabolism
- Amyloid beta-Protein Precursor/genetics
- Analysis of Variance
- Animals
- Benzothiazoles
- Corticosterone/blood
- Disease Models, Animal
- Hippocampus/metabolism
- Humans
- Mice
- Mice, Transgenic
- Mutation/genetics
- Plaque, Amyloid/metabolism
- Receptors, Corticotropin-Releasing Hormone/genetics
- Receptors, Corticotropin-Releasing Hormone/metabolism
- Receptors, Glucocorticoid/genetics
- Receptors, Glucocorticoid/metabolism
- Stress, Psychological/metabolism
- Stress, Psychological/pathology
- Thiazoles/metabolism
- CRF Receptor, Type 1
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Affiliation(s)
- H Dong
- Department of Psychiatry, Washington University School of Medicine, St Louis, MO 63110, USA. <>
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54
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Chewing ameliorates stress-induced suppression of hippocampal long-term potentiation. Neuroscience 2008; 154:1352-9. [DOI: 10.1016/j.neuroscience.2008.04.057] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2007] [Revised: 04/09/2008] [Accepted: 04/28/2008] [Indexed: 11/21/2022]
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55
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56
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He WB, Zhang JL, Hu JF, Zhang Y, Machida T, Chen NH. Effects of glucocorticoids on age-related impairments of hippocampal structure and function in mice. Cell Mol Neurobiol 2008; 28:277-91. [PMID: 17710532 PMCID: PMC11515799 DOI: 10.1007/s10571-007-9180-y] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2007] [Accepted: 07/28/2007] [Indexed: 12/20/2022]
Abstract
Effects of glucocorticoids (GCs) on maze-learning performances and hippocampal morphology were observed in male C57BL/6Cr mice. Correlations between aging, GCs and maze-learning performances were also studied. (2) Eight-arm radial maze was used in maze-learning tests. Learning performance was assessed by the parameters of time of getting all the bait, number of reentry errors into the already-entered arm with bait, and number of missed entries into an unbaited arm. Brain sections, 8 mum thick, were Nissl-stained with cresyl violet or stained immunocytochemically with antibodies against neurofilaments. (3) With aging, normal pyramidal cells decreased gradually in amount, and degenerating cells increased since the age of 18 months, accompanied with the maze-learning deficit. Here we have suggested that these changes were associated with the age-related deficits in adaptation tolerance of neurons to stress. In addition, the age-related deficits in plasticity of hippocampal neurons to GCs in young mice (3 months of age) resulted in an increase in plasma corticosterone (CORT) concentrations, degeneration of hippocampal pyramidal cells, as well as maze-learning deficits. (4) In conclusion, our data indicated that CORT caused the degeneration of hippocampal pyramidal cells and the impairment of memory.
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Affiliation(s)
- Wen-Bin He
- Department of Pharmacology, Institute of Materia Medica, Key Laboratory of Bioactive Substances and Resources Utilization, Ministry of Education, Chinese Academy of Medical Sciences & Peking Union Medical College, No. 1, Xiannongtan Street, Xuanwu District, Beijing, 100050 P.R. China
- Department of Basic Medical Sciences, Shanxi College of Traditional Chinese Medicine, Taiyuan, P.R. China
| | - Jun-Long Zhang
- Department of Basic Medical Sciences, Shanxi College of Traditional Chinese Medicine, Taiyuan, P.R. China
| | - Jin-Feng Hu
- Department of Pharmacology, Institute of Materia Medica, Key Laboratory of Bioactive Substances and Resources Utilization, Ministry of Education, Chinese Academy of Medical Sciences & Peking Union Medical College, No. 1, Xiannongtan Street, Xuanwu District, Beijing, 100050 P.R. China
| | - Yun Zhang
- Department of Pharmacology, Institute of Materia Medica, Key Laboratory of Bioactive Substances and Resources Utilization, Ministry of Education, Chinese Academy of Medical Sciences & Peking Union Medical College, No. 1, Xiannongtan Street, Xuanwu District, Beijing, 100050 P.R. China
| | - Takeo Machida
- Department of Regulation Biology, Faculty of Science, Saitama University, Saitama, Japan
| | - Nai-Hong Chen
- Department of Pharmacology, Institute of Materia Medica, Key Laboratory of Bioactive Substances and Resources Utilization, Ministry of Education, Chinese Academy of Medical Sciences & Peking Union Medical College, No. 1, Xiannongtan Street, Xuanwu District, Beijing, 100050 P.R. China
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57
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The relation of cortisol levels with hippocampus volumes under baseline and challenge conditions. Brain Res 2007; 1179:70-8. [DOI: 10.1016/j.brainres.2007.05.027] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2006] [Revised: 05/15/2007] [Accepted: 05/19/2007] [Indexed: 02/03/2023]
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58
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Perlman WR, Webster MJ, Herman MM, Kleinman JE, Weickert CS. Age-related differences in glucocorticoid receptor mRNA levels in the human brain. Neurobiol Aging 2007; 28:447-58. [PMID: 16540204 DOI: 10.1016/j.neurobiolaging.2006.01.010] [Citation(s) in RCA: 110] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2005] [Revised: 01/07/2006] [Accepted: 01/29/2006] [Indexed: 10/24/2022]
Abstract
Glucocorticoids and their receptors (GRs) are implicated in dynamic cognitive and neuroendocrine processes mediated by the prefrontal cortex and hippocampus. Additionally, a primary defect in forebrain GR levels can mimic symptoms of depression. We hypothesized that changes in GR mRNA levels may occur in the human brain across the life span thus positioning GR to differentially influence behavior and disease susceptibility. Following in situ hybridization with a riboprobe for human GR mRNA, we employed quantitative film autoradiography to measure expression levels in the prefrontal cortex and hippocampus in five age groups (infants, adolescents, young adults, adults, and aged) and in primary visual and visual association cortices for comparison. We detected a main effect of age group on cortical, but not hippocampal GR mRNA, with greater cortical expression in adolescents and adults than in infants or the aged. Increased GR mRNA in prefrontal cortex during adolescence and adulthood suggests that human GR-mediated forebrain regulation of cognition and the neuroendocrine stress response may be more salient during late maturation and at maturity.
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Affiliation(s)
- William R Perlman
- MiNDS Unit, Intramural Research Program, National Institute of Mental Health, National Institutes of Health, U.S. Department of Health and Human Services, Bethesda, MD 20892-1385, USA.
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59
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Csernansky JG, Dong H, Fagan AM, Wang L, Xiong C, Holtzman DM, Morris JC. Plasma cortisol and progression of dementia in subjects with Alzheimer-type dementia. Am J Psychiatry 2007. [PMID: 17151169 DOI: 10.1176/appi.ajp.163.12.2164] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
OBJECTIVE Studies of subjects with dementia of the Alzheimer type have reported correlations between increases in activity of the hypothalamic-pituitary-adrenal (HPA) axis and hippocampal degeneration. In this study, the authors sought to determine whether increases in plasma cortisol, a marker of HPA activity, were associated with clinical and cognitive measures of the rate of disease progression in subjects with Alzheimer-type dementia. METHOD Thirty-three subjects with very mild and mild Alzheimer-type dementia and 21 subjects without dementia were assessed annually for up to 4 years with the Clinical Dementia Rating scale and a battery of neuropsychological tests. Plasma was obtained at 8 a.m. on a single day and assayed for cortisol. Rates of change over time in the clinical and cognitive measures were derived from growth curve models. RESULTS In the subjects with dementia, but not in those without dementia, higher plasma cortisol levels were associated with more rapidly increasing symptoms of dementia and more rapidly decreasing performance on neuropsychological tests associated with temporal lobe function. No associations were observed between plasma cortisol levels and clinical and cognitive assessments obtained at the single assessment closest in time to the plasma collection. CONCLUSIONS Higher HPA activity, as reflected by increased plasma cortisol levels, is associated with more rapid disease progression in subjects with Alzheimer-type dementia.
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Affiliation(s)
- John G Csernansky
- Alzheimer's Disease Research Center and the Department of Psychiatry, Washington University School of Medicine, St. Louis, MO 63110, USA.
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60
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Nishida Y, Iinuma M, Tamura Y, Kubo KY, Iwaku F. Effect of tube feeding on hippocampal-dependent memory in SAMP1 mice. PEDIATRIC DENTAL JOURNAL 2007. [DOI: 10.1016/s0917-2394(07)70094-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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61
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Csernansky JG, Dong H, Fagan AM, Wang L, Xiong C, Holtzman DM, Morris JC. Plasma cortisol and progression of dementia in subjects with Alzheimer-type dementia. Am J Psychiatry 2006; 163:2164-9. [PMID: 17151169 PMCID: PMC1780275 DOI: 10.1176/ajp.2006.163.12.2164] [Citation(s) in RCA: 284] [Impact Index Per Article: 14.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
OBJECTIVE Studies of subjects with dementia of the Alzheimer type have reported correlations between increases in activity of the hypothalamic-pituitary-adrenal (HPA) axis and hippocampal degeneration. In this study, the authors sought to determine whether increases in plasma cortisol, a marker of HPA activity, were associated with clinical and cognitive measures of the rate of disease progression in subjects with Alzheimer-type dementia. METHOD Thirty-three subjects with very mild and mild Alzheimer-type dementia and 21 subjects without dementia were assessed annually for up to 4 years with the Clinical Dementia Rating scale and a battery of neuropsychological tests. Plasma was obtained at 8 a.m. on a single day and assayed for cortisol. Rates of change over time in the clinical and cognitive measures were derived from growth curve models. RESULTS In the subjects with dementia, but not in those without dementia, higher plasma cortisol levels were associated with more rapidly increasing symptoms of dementia and more rapidly decreasing performance on neuropsychological tests associated with temporal lobe function. No associations were observed between plasma cortisol levels and clinical and cognitive assessments obtained at the single assessment closest in time to the plasma collection. CONCLUSIONS Higher HPA activity, as reflected by increased plasma cortisol levels, is associated with more rapid disease progression in subjects with Alzheimer-type dementia.
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Affiliation(s)
- John G Csernansky
- Alzheimer's Disease Research Center and the Department of Psychiatry, Washington University School of Medicine, St. Louis, MO 63110, USA.
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62
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Chen Y, Fenoglio KA, Dubé CM, Grigoriadis DE, Baram TZ. Cellular and molecular mechanisms of hippocampal activation by acute stress are age-dependent. Mol Psychiatry 2006; 11:992-1002. [PMID: 16801951 PMCID: PMC2927976 DOI: 10.1038/sj.mp.4001863] [Citation(s) in RCA: 70] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/03/2006] [Revised: 05/30/2006] [Accepted: 06/05/2006] [Indexed: 11/09/2022]
Abstract
The effects of stress, including their putative contribution to pathological psychiatric conditions, are crucially governed by the age at which the stress takes place. However, the cellular and molecular foundations for the impact of stress on neuronal function, and their change with age, are unknown. For example, it is not known whether 'psychological' stress signals are perceived by similar neuronal populations at different ages, and whether they activate similar or age-specific signaling pathways that might then mediate the spectrum of stress-evoked neuronal changes. We employed restraint and restraint/noise stress to address these issues in juvenile (postnatal day 18, [P18]) and adult rats, and used phosphorylation of the transcription factor CREB (pCREB) and induction of c-fos as markers of hippocampal neuronal responses. Stress-activated neuronal populations were identified both anatomically and biochemically, and selective blockers of the stress-activated hippocampal peptide, corticotropin-releasing hormone (CRH) were used to probe the role of this molecule in stress-induced hippocampal cell activation. Stress evoked strikingly different neuronal response patterns in immature vs adult hippocampus. Expression of pCREB appeared within minutes in hippocampal CA3 pyramidal cells of P18 rats, followed by delayed induction of Fos protein in the same cell population. In contrast, basal pCREB levels were high in adult hippocampus and were not altered at 10-120 min by stress. Whereas Fos induction was elicited by stress in the adult, it was essentially confined to area CA1, with little induction in CA3. At both age groups, central pretreatment with either a nonselective blocker of CRH receptors (alpha-helical CRH [9-41]) or the CRF1-selective antagonist, NBI 30775, abolished stress-evoked neuronal activation. In conclusion, hippocampal neuronal responses to psychological stress are generally more rapid and robust in juvenile rats, compared to fully mature adults, and at both ages, CRH plays a key role in this process. Enhanced hippocampal response to stress during development, and particularly the activation of the transcription factor CREB, may contribute to the enduring effects of stress during this period on hippocampal function.
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Affiliation(s)
- Y Chen
- Department of Pediatrics, University of California at Irvine, Irvine, CA, USA
| | - KA Fenoglio
- Department of Anatomy/Neurobiology, University of California at Irvine, Irvine, CA, USA
| | - CM Dubé
- Department of Pediatrics, University of California at Irvine, Irvine, CA, USA
| | | | - TZ Baram
- Department of Pediatrics, University of California at Irvine, Irvine, CA, USA
- Department of Anatomy/Neurobiology, University of California at Irvine, Irvine, CA, USA
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63
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Abrahám IM, Meerlo P, Luiten PGM. Concentration dependent actions of glucocorticoids on neuronal viability and survival. Dose Response 2006; 4:38-54. [PMID: 18648635 DOI: 10.2203/dose-response.004.01.004.abraham] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
A growing body of evidence based on experimental data demonstrates that glucocorticoids (GCs) can play a potent role in the survival and death of neurons. However, these observations reflect paradoxical features of GCs, since these adrenal stress hormones are heavily involved in both neurodegenerative and neuroprotective processes. The actual level of GCs appears to have an essential impact in this bimodal action. In the present short review we aim to show the importance of concentration dependent action of GCs on neuronal cell viability and cell survival in the brain. Additionally, we will summarize the possible GC-induced cellular mechanisms at different GC concentrations providing a background for their effect on the fate of nerve cells in conditions that are a challenge to their survival.
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Affiliation(s)
- István M Abrahám
- Neurobiology Research Group, Hungarian Academy of Sciences at Eötvös Loránd University, Budapest, Hungary
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64
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Husum H, Aznar S, Høyer-Hansen S, Larsen MH, Mikkelsen JD, Møller A, Mathé AA, Wörtwein G. Exacerbated loss of cell survival, neuropeptide Y-immunoreactive (IR) cells, and serotonin-IR fiber lengths in the dorsal hippocampus of the aged flinders sensitive line “depressed” rat: Implications for the pathophysiology of depression? J Neurosci Res 2006; 84:1292-302. [PMID: 17099915 DOI: 10.1002/jnr.21027] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Impairment of hippocampal neurogenesis has been proposed to provide a cellular basis for the development of major depression. Studies have shown that serotonin (5-HT) and neuropeptide Y (NPY) may be involved in stimulating cell proliferation in the dentate gyrus. The Flinders-sensitive line (FSL) rat represents a genetic model of depression with characterized 5-HT and NPY abnormalities in the hippocampus. Consequently, it could be hypothesized that hippocampal neurogenesis in the FSL rat would be impaired. The present study examined the relationship among 1) number of BrdU-immunoreactive (IR) cells, 2) NPY-IR cells in the dentate gyrus, and 3) length of 5-HT-IR fibers in the dorsal hippocampus, as well as volume and number of 5-HT-IR cells in the dorsal raphé nucleus, in adult and aged FSL rats and control Flinders-resistant line (FRL) rats. Surprisingly, adult FSL rats had significantly more BrdU-IR and NPY-IR cells compared with adult FRL rats. However, aging caused an exacerbated loss of these cell types in the FSL strain compared with FRL. The aged FSL rats also had shortened 5-HT-IR fibers in the dorsal hippocampus, indicative of an impaired 5-HT innervation of this area, compared with FRL. These results suggest that, for "depressed" FSL rats, compared with FRL rats, aging is associated with an excacerbated loss of newly formed cells in addition to NPY-IR cells and 5-HT-IR dendrites in the hippocampus. These observations may be of relevance to the depression-like behavior of the FSL rat and, by inference, to the pathophysiology of depression.
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Affiliation(s)
- H Husum
- Disease Pharmacology, Department of Psychopharmacology, Lundbeck A/S, Valby, Denmark.
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Brunson KL, Kramár E, Lin B, Chen Y, Colgin LL, Yanagihara TK, Lynch G, Baram TZ. Mechanisms of late-onset cognitive decline after early-life stress. J Neurosci 2005; 25:9328-38. [PMID: 16221841 PMCID: PMC3100717 DOI: 10.1523/jneurosci.2281-05.2005] [Citation(s) in RCA: 373] [Impact Index Per Article: 18.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2005] [Revised: 08/05/2005] [Accepted: 08/15/2005] [Indexed: 12/24/2022] Open
Abstract
Progressive cognitive deficits that emerge with aging are a result of complex interactions of genetic and environmental factors. Whereas much has been learned about the genetic underpinnings of these disorders, the nature of "acquired" contributing factors, and the mechanisms by which they promote progressive learning and memory dysfunction, remain largely unknown. Here, we demonstrate that a period of early-life "psychological" stress causes late-onset, selective deterioration of both complex behavior and synaptic plasticity: two forms of memory involving the hippocampus, were severely but selectively impaired in middle-aged, but not young adult, rats exposed to fragmented maternal care during the early postnatal period. At the cellular level, disturbances to hippocampal long-term potentiation paralleled the behavioral changes and were accompanied by dendritic atrophy and mossy fiber expansion. These findings constitute the first evidence that a short period of stress early in life can lead to delayed, progressive impairments of synaptic and behavioral measures of hippocampal function, with potential implications to the basis of age-related cognitive disorders in humans.
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Affiliation(s)
- Kristen L Brunson
- Department of Anatomy/Neurobiology, University of California, Irvine, California 92697-4475, USA
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66
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Gerges NZ, Alzoubi KH, Park CR, Diamond DM, Alkadhi KA. Adverse effect of the combination of hypothyroidism and chronic psychosocial stress on hippocampus-dependent memory in rats. Behav Brain Res 2004; 155:77-84. [PMID: 15325781 DOI: 10.1016/j.bbr.2004.04.003] [Citation(s) in RCA: 97] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2004] [Revised: 03/19/2004] [Accepted: 04/06/2004] [Indexed: 01/05/2023]
Abstract
Both hypothyroidism and stress interfere with cognitive function in patients. This study examined the effect of hypothyroidism and stress on hippocampus-dependent learning and memory in rats using the novel radial arm water maze (RAWM), which measures spatial working memory. Hypothyroidism was accomplished by thyroidectomy and 2 weeks later a form of intruder stress was used as the chronic psychosocial stressor. After 4-6 weeks of stress, rats were trained to learn (during the acquisition phase; four trials) and then remember (during two memory test trials occurring 15 and 120 min after the acquisition phase) the within-day location of a hidden escape platform, which was in different arm every day. The number of errors (entry into arms other than the platform arm) was noted. Within-day learning of the platform location was largely unaffected by the experimental manipulations, indicating that rats in all groups were equally capable of finding the platform to escape from the water with similar numbers of errors (P > 0.005). The number of days a rat took to reach a criterion (DTC; a maximum of one error in three consecutive days) indicated that chronic stress or hypothyroidism, alone, resulted in a mild impairment of spatial memory, and the combination of chronic stress and hypothyroidism resulted in a more severe and long-lasting memory impairment. The data indicated that the combination of stress and hypothyroidism produced more deleterious effects on hippocampal function than either chronic stress or hypothyroidism alone.
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Affiliation(s)
- Nashaat Z Gerges
- Department of Pharmacological and Pharmaceutical Sciences, University of Houston, Houston, TX 77204-5515, USA
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67
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Heine VM, Maslam S, Joëls M, Lucassen PJ. Prominent decline of newborn cell proliferation, differentiation, and apoptosis in the aging dentate gyrus, in absence of an age-related hypothalamus-pituitary-adrenal axis activation. Neurobiol Aging 2004; 25:361-75. [PMID: 15123342 DOI: 10.1016/s0197-4580(03)00090-3] [Citation(s) in RCA: 238] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2002] [Revised: 03/13/2003] [Accepted: 03/25/2003] [Indexed: 11/27/2022]
Abstract
Neurogenesis and apoptosis in the hippocampal dentate gyrus (DG) occur during development and adulthood. However, little is known about how these two processes relate to each other during aging. In this study, we examined apoptosis, proliferation, migration, and survival of newborn cells in the young (2 weeks), young-adult (6 weeks), middle-aged (12 months), and old (24 months) rat DG. We also measured dentate volume and cell numbers, along with basal corticosterone and stress response parameters. We show that new cell proliferation and apoptosis slow down profoundly over this time period. Moreover, migration and differentiation into a neuronal or glial phenotype was strongly reduced from 6 weeks of age onwards; it was hardly present in middle-aged and old rats as confirmed by confocal analysis. Surprisingly, we found no correlation between cell birth and corticosterone levels or stress response parameters in any age group.
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Affiliation(s)
- Vivi M Heine
- Institute for Neurobiology, Faculty of Science, Swammerdam Institute for Life Sciences, University of Amsterdam, Kruislaan 320, 1098 SM, Amsterdam, The Netherlands.
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68
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Abstract
Aging is often simply defined as the decline in various body systems and functions (eg, endocrine, cognitive, motor, etc) that occur with the passage of time, although the degree of deterioration can vary greatly across individuals. Increases in average life span have brought a greater focus on brain aging. There is an emphasis on understanding how aging contributes to a decline in brain functions (eg, cognition) because such a decline adversely affects the quality of life. The hippocampus is a key brain structure for cognition and the feedback control of the stress response. Herein we describe how the hippocampus changes with age and we examine the idea that age-related changes in the secretory patterns of the hypothalamic-pituitary adrenal (HPA) axis can contribute to hippocampal aging. We also examine the proposal that cumulative stress, perhaps due to compromised HPA axis function, can contribute to hippocampal aging by subjecting it to exposure to excessive levels of glucocorticoids. The aging hippocampus does not appear to suffer a generalized loss of cells or synapses, although atrophy of the structure may occur in humans. Thus, age-related cognitive impairments are likely related to other neurobiological alterations that could include changes in the signaling, information encoding, and plastic, electrophysiological, or neurochemical properties of neurons or glia. Dysfunction of the HPA axis sometimes occurs with aging, and while excessive glucocorticoids can disrupt cognition as well as hippocampal neuronal integrity, these are not an inevitable consequence of aging. The general preservation of cells and the plastic potential of the hippocampus provide a focus for the development of pharmacological, nutritional, or life-style strategies to combat age-related declines.
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Affiliation(s)
- D B Miller
- Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health, Morgantown, WV 26505, USA
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Tannenbaum BM, Tannenbaum GS, Anisman H. Impact of life-long macronutrient choice on neuroendocrine and cognitive functioning in aged mice: differential effects in stressor-reactive and stressor-resilient mouse strains. Brain Res 2003; 985:187-97. [PMID: 12967723 DOI: 10.1016/s0006-8993(03)03196-2] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Nutrient selection emerges as a result of both genetic and environmental factors and may be further modified by stressors. The impact of this complex interrelationship on pathological outcomes is poorly understood. In the present investigation the stressor-reactive BALB/cByJ and the relatively stressor resilient C57BL/6ByJ mice were maintained on a macronutrient selection protocol or given free access to chow for 20 months. The C57BL/6ByJ mice exhibited a marked preference for fat over carbohydrates, whereas BALB/cByJ mice preferred carbohydrates over fat. Cognitive testing in a Morris water maze indicated that while BALB/cByJ mice were clearly more impaired in this task relative to their C57BL/6ByJ counterparts, there was no substantial effect of the diet at either 13 or 19 months of age. Furthermore, despite their stressor resiliency, at 19 months of age, C57BL/6ByJ mice who invariably consumed fat, exhibited greater plasma corticosterone responses to a 20-min period of restraint than chow fed animals. Indeed, the corticosterone rise was as pronounced as in the more reactive BALB/cByJ strain. Furthermore, the C57BL/6ByJ diet-fed mice showed features of insulin insensitivity and increased adiposity. These data suggest that the adverse effects of fat consumption need to be considered in the context of genetically determined vulnerability/resilience factors.
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Affiliation(s)
- Beth M Tannenbaum
- Institute of Neuroscience, Carleton University, Ottawa, Ontario, Canada K1S 5B6.
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Watanabe K, Ozono S, Nishiyama K, Saito S, Tonosaki K, Fujita M, Onozuka M. The molarless condition in aged SAMP8 mice attenuates hippocampal Fos induction linked to water maze performance. Behav Brain Res 2002; 128:19-25. [PMID: 11755686 DOI: 10.1016/s0166-4328(01)00268-6] [Citation(s) in RCA: 77] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
The involvement of dysfunctional teeth in senile hippocampal activity was evaluated by examining, in aged SAMP8 mice, the effect of cutting off the upper molars (molarless condition) on hippocampal induction of the protein product, Fos, of the immediate early gene, c-fos, and on spatial performance in a water maze. The molarless condition caused a reduction in the number of Fos-positive cells in the hippocampal CA1 region, in which Fos immunoreactivity was localized in the cell nuclei. This effect was more pronounced the longer the molarless condition persisted. The suppression of both learning ability and Fos induction in the CA1 induced by the molarless condition was considerably reduced by restoring the lost molars with artificial crowns. Taken together with the plethora of research showing a relationship between stress, aging and hippocampal function and our past findings [Brain Res. 1999; 826: 148-53; Behav. Brain Res. 2000;108: 145-55; Exp. Gerontol. 2001; 36:283-95], the present results suggest the detrimental effects of a reduction in chewing on hippocampal processing in aged SAMP8 mice that would be linked with stress induced by the molarless condition.
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Affiliation(s)
- Kazuko Watanabe
- Department of Physiology, Gifu University School of Medicine, Gifu 500-8705, Japan
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