201
|
Influences of prenatal and postnatal stress on adult hippocampal neurogenesis: the double neurogenic niche hypothesis. Behav Brain Res 2014; 281:309-17. [PMID: 25546722 DOI: 10.1016/j.bbr.2014.12.036] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2014] [Revised: 12/11/2014] [Accepted: 12/15/2014] [Indexed: 01/07/2023]
Abstract
Adult hippocampal neurogenesis (AHN) is involved in learning, memory, and stress, and plays a significant role in neurodegenerative and psychiatric disorders. As an age-dependent process, AHN is largely influenced by changes that occur during the pre- and postnatal stages of brain development, and constitutes an important field of research. This review examines the current knowledge regarding the regulators of AHN and the influence of prenatal and postnatal stress on later AHN. In addition, a hypothesis is presented suggesting that each kind of stress influences a specific neurogenic pool, developmental or postnatal, that later becomes a precursor with important repercussions for AHN. This hypothesis is referred to as "the double neurogenic niche hypothesis." Discovering what receptors, transcription factors, or genes are specifically activated by different stressors is proposed as an essential line of future research in the field. Such knowledge shall constitute an important starting point toward the goal of modifying AHN in neurodegenerative or psychiatric diseases.
Collapse
|
202
|
Formyl peptide receptor as a novel therapeutic target for anxiety-related disorders. PLoS One 2014; 9:e114626. [PMID: 25517119 PMCID: PMC4269406 DOI: 10.1371/journal.pone.0114626] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2014] [Accepted: 11/11/2014] [Indexed: 01/09/2023] Open
Abstract
Formyl peptide receptors (FPR) belong to a family of sensors of the immune system that detect microbe-associated molecules and inform various cellular and sensorial mechanisms to the presence of pathogens in the host. Here we demonstrate that Fpr2/3-deficient mice show a distinct profile of behaviour characterised by reduced anxiety in the marble burying and light-dark box paradigms, increased exploratory behaviour in an open-field, together with superior performance on a novel object recognition test. Pharmacological blockade with a formyl peptide receptor antagonist, Boc2, in wild type mice reproduced most of the behavioural changes observed in the Fpr2/3-/- mice, including a significant improvement in novel object discrimination and reduced anxiety in a light/dark shuttle test. These effects were associated with reduced FPR signalling in the gut as shown by the significant reduction in the levels of p-p38. Collectively, these findings suggest that homeostatic FPR signalling exerts a modulatory effect on anxiety-like behaviours. These findings thus suggest that therapies targeting FPRs may be a novel approach to ameliorate behavioural abnormalities present in neuropsychiatric disorders at the cognitive-emotional interface.
Collapse
|
203
|
Aimone JB, Li Y, Lee SW, Clemenson GD, Deng W, Gage FH. Regulation and function of adult neurogenesis: from genes to cognition. Physiol Rev 2014; 94:991-1026. [PMID: 25287858 DOI: 10.1152/physrev.00004.2014] [Citation(s) in RCA: 419] [Impact Index Per Article: 41.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Adult neurogenesis in the hippocampus is a notable process due not only to its uniqueness and potential impact on cognition but also to its localized vertical integration of different scales of neuroscience, ranging from molecular and cellular biology to behavior. This review summarizes the recent research regarding the process of adult neurogenesis from these different perspectives, with particular emphasis on the differentiation and development of new neurons, the regulation of the process by extrinsic and intrinsic factors, and their ultimate function in the hippocampus circuit. Arising from a local neural stem cell population, new neurons progress through several stages of maturation, ultimately integrating into the adult dentate gyrus network. The increased appreciation of the full neurogenesis process, from genes and cells to behavior and cognition, makes neurogenesis both a unique case study for how scales in neuroscience can link together and suggests neurogenesis as a potential target for therapeutic intervention for a number of disorders.
Collapse
Affiliation(s)
- James B Aimone
- Cognitive Modeling Group, Sandia National Laboratories, Albuquerque, New Mexico; and Laboratory of Genetics, Salk Institute for Biological Studies, La Jolla, California
| | - Yan Li
- Cognitive Modeling Group, Sandia National Laboratories, Albuquerque, New Mexico; and Laboratory of Genetics, Salk Institute for Biological Studies, La Jolla, California
| | - Star W Lee
- Cognitive Modeling Group, Sandia National Laboratories, Albuquerque, New Mexico; and Laboratory of Genetics, Salk Institute for Biological Studies, La Jolla, California
| | - Gregory D Clemenson
- Cognitive Modeling Group, Sandia National Laboratories, Albuquerque, New Mexico; and Laboratory of Genetics, Salk Institute for Biological Studies, La Jolla, California
| | - Wei Deng
- Cognitive Modeling Group, Sandia National Laboratories, Albuquerque, New Mexico; and Laboratory of Genetics, Salk Institute for Biological Studies, La Jolla, California
| | - Fred H Gage
- Cognitive Modeling Group, Sandia National Laboratories, Albuquerque, New Mexico; and Laboratory of Genetics, Salk Institute for Biological Studies, La Jolla, California
| |
Collapse
|
204
|
Hubens CJ, Kaptein PS, ter Horst JP, Voskuyl RA, Schenk GJ. Kainate-induced epileptogenesis alters circular hole board learning strategy but not the performance of C57BL/6J mice. Epilepsy Behav 2014; 41:127-35. [PMID: 25461204 DOI: 10.1016/j.yebeh.2014.09.038] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/17/2014] [Accepted: 09/12/2014] [Indexed: 01/12/2023]
Abstract
Patients with mesial temporal lobe epilepsy (mTLE) frequently show cognitive deficits. However, the relation between mTLE and cognitive impairment is poorly understood. To gain more insight into epilepsy-associated alterations in cognitive performance, we studied the spatial learning of C57BL/6J mice five weeks after kainate-induced status epilepticus (SE). Typically, structural hippocampal rearrangements take place within five weeks after SE. Mice were monitored by exposing them to four tasks with a focus on spatial memory and anxiety: the circular hole board, modified hole board, novel object-placement task, and elevated plus maze. On the circular hole board, animals showed a higher preference for hippocampus-independent strategies after SE. In contrast, no change in strategy was seen on the modified hole board, but animals with SE were able to finish the task more often. Animals did not have an increased preference for a relocated object in the novel object-placement task but showed an increased locomotion after SE. No indications for altered anxiety were found when tested on the elevated plus maze following SE. These data suggest that the circular hole board is a well-suited paradigm to detect subtle SE-induced hippocampal deficits.
Collapse
Affiliation(s)
- Chantal J Hubens
- Stichting Epilepsie Instellingen Nederland (SEIN), Heemstede, The Netherlands; Department of Pharmacology, Leiden Academic Center for Drug Research (LACDR), Leiden, The Netherlands.
| | - Pascale S Kaptein
- Department of Pharmacology, Leiden Academic Center for Drug Research (LACDR), Leiden, The Netherlands
| | - Judith P ter Horst
- Department of Medical Pharmacology, Leiden University Medical Center (LUMC) & LACDR, Leiden, The Netherlands
| | - Rob A Voskuyl
- Stichting Epilepsie Instellingen Nederland (SEIN), Heemstede, The Netherlands; Department of Pharmacology, Leiden Academic Center for Drug Research (LACDR), Leiden, The Netherlands
| | - Geert J Schenk
- Department of Medical Pharmacology, Leiden University Medical Center (LUMC) & LACDR, Leiden, The Netherlands
| |
Collapse
|
205
|
Levone BR, Cryan JF, O'Leary OF. Role of adult hippocampal neurogenesis in stress resilience. Neurobiol Stress 2014; 1:147-55. [PMID: 27589664 PMCID: PMC4721321 DOI: 10.1016/j.ynstr.2014.11.003] [Citation(s) in RCA: 137] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2014] [Revised: 10/30/2014] [Accepted: 11/03/2014] [Indexed: 02/04/2023] Open
Abstract
There is a growing appreciation that adult hippocampal neurogenesis plays a role in emotional and cognitive processes related to psychiatric disorders. Although many studies have investigated the effects of stress on adult hippocampal neurogenesis, most have not focused on whether stress-induced changes in neurogenesis occur specifically in animals that are more resilient or more susceptible to the behavioural and neuroendocrine effects of stress. Thus, in the present review we explore whether there is a clear relationship between stress-induced changes in adult hippocampal neurogenesis, stress resilience and antidepressant-induced recovery from stress-induced changes in behaviour. Exposure to different stressors is known to reduce adult hippocampal neurogenesis, but some stressors have also been shown to exert opposite effects. Ablation of neurogenesis does not lead to a depressive phenotype, but it can enhance responsiveness to stress and affect stress susceptibility. Monoaminergic-targeted antidepressants, environmental enrichment and adrenalectomy are beneficial for reversing stress-induced changes in behaviour and have been shown to do so in a neurogenesis-dependant manner. In addition, stress and antidepressants can affect hippocampal neurogenesis, preferentially in the ventral hippocampus. Together, these data show that adult hippocampal neurogenesis may play a role in the neuroendocrine and behavioural responses to stress, although it is not yet fully clear under which circumstances neurogenesis promotes resilience or susceptibility to stress. It will be important that future studies carefully examine how adult hippocampal neurogenesis can contribute to stress resilience/susceptibility so that it may be appropriately exploited for the development of new and more effective treatments for stress-related psychiatric disorders. Ablation of adult hippocampal NG can affect stress susceptibility. Increased hippocampal NG is associated with both susceptibility and resilience. Adult hippocampal NG can influence stress-induced alterations in HPA-axis activity. Behavioural effects of some but not all antidepressants are neurogenesis-dependent. Stress and antidepressants can affect NG preferentially in the ventral hippocampus.
Collapse
Affiliation(s)
- Brunno R Levone
- Department of Anatomy and Neuroscience, University College Cork, Ireland
| | - John F Cryan
- Department of Anatomy and Neuroscience, University College Cork, Ireland; Alimentary Pharmabiotic Centre, University College Cork, Ireland
| | - Olivia F O'Leary
- Department of Anatomy and Neuroscience, University College Cork, Ireland; Alimentary Pharmabiotic Centre, University College Cork, Ireland
| |
Collapse
|
206
|
Clemenson GD, Lee SW, Deng W, Barrera VR, Iwamoto KS, Fanselow MS, Gage FH. Enrichment rescues contextual discrimination deficit associated with immediate shock. Hippocampus 2014; 25:385-92. [PMID: 25330953 DOI: 10.1002/hipo.22380] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/14/2014] [Indexed: 01/24/2023]
Abstract
Adult animals continue to modify their behavior throughout life, a process that is highly influenced by past experiences. To shape behavior, specific mechanisms of neural plasticity to learn, remember, and recall information are required. One of the most robust examples of adult plasticity in the brain occurs in the dentate gyrus (DG) of the hippocampus, through the process of adult neurogenesis. Adult neurogenesis is strongly upregulated by external factors such as voluntary wheel running (RUN) and environmental enrichment (EE); however, the functional differences between these two factors remain unclear. Although both manipulations result in increased neurogenesis, RUN dramatically increases the proliferation of newborn cells and EE promotes their survival. We hypothesize that the method by which these newborn neurons are induced influences their functional role. Furthermore, we examine how EE-induced neurons may be primed to encode and recognize features of novel environments due to their previous enrichment experience. Here, we gave mice a challenging contextual fear-conditioning (FC) procedure to tease out the behavioral differences between RUN-induced neurogenesis and EE-induced neurogenesis. Despite the robust increases in neurogenesis seen in the RUN mice, we found that only EE mice were able to discriminate between similar contexts in this task, indicating that EE mice might use a different cognitive strategy when processing contextual information. Furthermore, we showed that this improvement was dependent on EE-induced neurogenesis, suggesting a fundamental functional difference between RUN-induced neurogenesis and EE-induced neurogenesis.
Collapse
Affiliation(s)
- Gregory D Clemenson
- Laboratory of Genetics, Salk Institute for Biological Sciences, La Jolla, California
| | | | | | | | | | | | | |
Collapse
|
207
|
O'Leary OF, Cryan JF. A ventral view on antidepressant action: roles for adult hippocampal neurogenesis along the dorsoventral axis. Trends Pharmacol Sci 2014; 35:675-87. [PMID: 25455365 DOI: 10.1016/j.tips.2014.09.011] [Citation(s) in RCA: 138] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2014] [Revised: 09/29/2014] [Accepted: 09/30/2014] [Indexed: 11/26/2022]
Abstract
Adult hippocampal neurogenesis is implicated in antidepressant action, stress responses, and cognitive functioning. The hippocampus is functionally segregated along its longitudinal axis into dorsal (dHi) and ventral (vHi) regions in rodents, and analogous posterior and anterior regions in primates, whereby the vHi preferentially regulates stress and anxiety, while the dHi preferentially regulates spatial learning and memory. Given the role of neurogenesis in functions preferentially regulated by the dHi or vHi, it is plausible that neurogenesis is preferentially regulated in either the dHi or vHi depending upon the stimulus. We appraise here the literature on the effects of stress and antidepressants on neurogenesis along the hippocampal longitudinal axis and explore whether preferential regulation of neurogenesis in the vHi/anterior hippocampus contributes to stress resilience and antidepressant action.
Collapse
Affiliation(s)
- Olivia F O'Leary
- Department of Anatomy and Neuroscience, University College Cork, Cork, Ireland; Alimentary Pharmabiotic Centre, University College Cork, Cork, Ireland.
| | - John F Cryan
- Department of Anatomy and Neuroscience, University College Cork, Cork, Ireland; Alimentary Pharmabiotic Centre, University College Cork, Cork, Ireland
| |
Collapse
|
208
|
Yuan TF, Slotnick BM. Roles of olfactory system dysfunction in depression. Prog Neuropsychopharmacol Biol Psychiatry 2014; 54:26-30. [PMID: 24879990 DOI: 10.1016/j.pnpbp.2014.05.013] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/20/2014] [Revised: 05/22/2014] [Accepted: 05/22/2014] [Indexed: 01/26/2023]
Abstract
The olfactory system is involved in sensory functions, emotional regulation and memory formation. Olfactory bulbectomy in rat has been employed as an animal model of depression for antidepressant discovery studies for many years. Olfaction is impaired in animals suffering from chronic stress, and patients with clinical depression were reported to have decreased olfactory function. It is believed that the neurobiological bases of depression might include dysfunction in the olfactory system. Further, brain stimulation, including nasal based drug delivery could provide novel therapies for management of depression.
Collapse
Affiliation(s)
- Ti-Fei Yuan
- School of Psychology, Nanjing Normal University, China.
| | | |
Collapse
|
209
|
Jakob S, Schraut KG, Schmitt AG, Scholz CJ, Ortega G, Steinbusch HW, Lesch KP, van den Hove DLA. Differential effects of prenatal stress in female 5-HTT-deficient mice: towards molecular mechanisms of resilience. Dev Neurosci 2014; 36:454-64. [PMID: 25195605 DOI: 10.1159/000363695] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2013] [Accepted: 05/13/2014] [Indexed: 11/19/2022] Open
Abstract
Prenatal stress (PS) exposure is known to increase the risk of developing emotional disorders like major depression in later life. However, some individuals do not succumb to adversity following developmental stress exposure, a phenomenon referred to as resilience. To date, the molecular mechanisms explaining why some subjects are vulnerable and others more resilient to PS are far from understood. Recently, we have shown that the serotonin transporter (5-HTT) gene may play a modulating role in rendering individuals susceptible or resilient to PS. However, it is not clear which molecular players are mediating the interaction between PS and the 5-Htt genotype in the context of vulnerability and resilience to PS. For this purpose, we performed a microarray study with the help of Affymetrix GeneChip® Mouse Genome 430 2.0 Array, in which we separated wild-type and heterozygous 5-Htt-deficient (5-Htt+/-) PS offspring into susceptible and resilient offspring according to their performance in the forced swim test. Performance-oriented LIMMA analysis on the mRNA expression microarray data was followed by subsequent Spearman's correlation analysis linking the individual qRT-PCR mRNA expression data to various anxiety- and depression-related behavioral and neuroendocrine measures. Results indicate that, amongst others, Fos-induced growth factor (Figf), galanin receptor 3 (Galr3), growth hormone (Gh) and prolactin (Prl) were differentially expressed specifically in resilient offspring when compared to controls, and that the hippocampal expression of these genes showed several strong correlations with various measures of the hypothalamus-pituitary-adrenal axis (re)activity. In conclusion, there seems to be an intricate interplay between the expression of Figf, Galr3, Gh and Prl and neuroendocrine regulation, which may be critical in mediating resilience to PS exposure. More insight into the exact role of these molecular players may significantly enhance the development of new treatment strategies for stress-related emotional disorders.
Collapse
Affiliation(s)
- Sissi Jakob
- Department of Neuroscience, School for Mental Health and Neuroscience (MHENS), Maastricht University, Maastricht, The Netherlands
| | | | | | | | | | | | | | | |
Collapse
|
210
|
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.
Collapse
|
211
|
Abstract
Corticosteroids secreted as end product of the hypothalamic-pituitary-adrenal axis act like a double-edged sword in the brain. The hormones coordinate appraisal processes and decision making during the initial phase of a stressful experience and promote subsequently cognitive performance underlying the management of stress adaptation. This action exerted by the steroids on the initiation and termination of the stress response is mediated by 2 related receptor systems: mineralocorticoid receptors (MRs) and glucocorticoid receptors (GRs). The receptor types are unevenly distributed but colocalized in abundance in neurons of the limbic brain to enable these complementary hormone actions. This contribution starts from a historical perspective with the observation that phasic occupancy of GR during ultradian rhythmicity is needed to maintain responsiveness to corticosteroids. Then, during stress, initially MR activation enhances excitability of limbic networks that are engaged in appraisal and emotion regulation. Next, the rising hormone concentration occupies GR, resulting in reallocation of energy to limbic-cortical circuits with a role in behavioral adaptation and memory storage. Upon MR:GR imbalance, dysregulation of the hypothalamic-pituitary-adrenal axis occurs, which can enhance an individual's vulnerability. Imbalance is characteristic for chronic stress experience and depression but also occurs during exposure to synthetic glucocorticoids. Hence, glucocorticoid psychopathology may develop in susceptible individuals because of suppression of ultradian/circadian rhythmicity and depletion of endogenous corticosterone from brain MR. This knowledge generated from testing the balance hypothesis can be translated to a rational glucocorticoid therapy.
Collapse
Affiliation(s)
- E Ron de Kloet
- Department of Medical Pharmacology, Leiden Academic Centre for Drug Research, Leiden University and Department of Endocrinology and Metabolism, Leiden University Medical Center, 2300 RA Leiden, The Netherlands
| |
Collapse
|
212
|
Stress modulation of hippocampal activity – Spotlight on the dentate gyrus. Neurobiol Learn Mem 2014; 112:53-60. [DOI: 10.1016/j.nlm.2014.04.008] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2013] [Revised: 03/17/2014] [Accepted: 04/08/2014] [Indexed: 12/18/2022]
|
213
|
Smarr BL, Jennings KJ, Driscoll JR, Kriegsfeld LJ. A time to remember: the role of circadian clocks in learning and memory. Behav Neurosci 2014; 128:283-303. [PMID: 24708297 PMCID: PMC4385793 DOI: 10.1037/a0035963] [Citation(s) in RCA: 113] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The circadian system has pronounced influence on learning and memory, manifesting as marked changes in memory acquisition and recall across the day. From a mechanistic perspective, the majority of studies have investigated mammalian hippocampal-dependent learning and memory, as this system is highly tractable. The hippocampus plays a major role in learning and memory, and has the potential to integrate circadian information in many ways, including information from local, independent oscillators, and through circadian modulation of neurogenesis, synaptic remodeling, intracellular cascades, and epigenetic regulation of gene expression. These local processes are combined with input from other oscillatory systems to synergistically augment hippocampal rhythmic function. This overview presents an account of the current state of knowledge on circadian interactions with learning and memory circuitry and provides a framework for those interested in further exploring these interactions.
Collapse
Affiliation(s)
- Benjamin L. Smarr
- Department of Psychology, University of California, Berkeley, CA, 94720 USA
| | | | - Joseph R. Driscoll
- The Helen Wills Neuroscience Institute, University of California, Berkeley, CA, 94720 USA
| | - Lance J. Kriegsfeld
- Department of Psychology, University of California, Berkeley, CA, 94720 USA
- The Helen Wills Neuroscience Institute, University of California, Berkeley, CA, 94720 USA
| |
Collapse
|
214
|
Lindsey BW, Tropepe V. Changes in the social environment induce neurogenic plasticity predominantly in niches residing in sensory structures of the zebrafish brain independently of cortisol levels. Dev Neurobiol 2014; 74:1053-77. [PMID: 24753454 DOI: 10.1002/dneu.22183] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2013] [Revised: 01/31/2014] [Accepted: 04/14/2014] [Indexed: 11/07/2022]
Abstract
The social environment is known to modulate adult neurogenesis. Studies in mammals and birds have shown a strong correlation between social isolation and decreases in neurogenesis, whereas time spent in an enriched environment has been shown to restore these deficits and enhance neurogenesis. These data suggest that there exists a common adaptive response among neurogenic niches to each extreme of the social environment. We sought to further test this hypothesis in zebrafish, a social species with distinct neurogenic niches within primary sensory structures and telencephalic nuclei of the brain. By examining stages of adult neurogenesis, including the proliferating stem/progenitor population, their surviving cohort, and the resulting newly differentiated neuronal population, we show that niches residing in sensory structures are most sensitive to changes in the social context, and that social isolation or novelty are both capable of decreasing the number of proliferating cells while increasing the number of newborn neurons within a single niche. Contrary to observations in rodents, we demonstrate that social novelty, a form of enrichment, does not consistently rescue deficits in cell proliferation following social isolation, and that cortisol levels do not negatively regulate changes in adult neurogenesis, but are correlated with the social context. We propose that enhancement or suppression of adult neurogenesis in the zebrafish brain under different social contexts depends largely on the type of niche (sensory or telencephalic), experience from the preceding social environment, and occurs independently of changes in cortisol levels.
Collapse
Affiliation(s)
- Benjamin W Lindsey
- Department of Cell and Systems Biology, University of Toronto, Ontario, M5S 3G5, Canada
| | | |
Collapse
|
215
|
Alcohol exposure inhibits adult neural stem cell proliferation. Exp Brain Res 2014; 232:2775-84. [PMID: 24770860 DOI: 10.1007/s00221-014-3958-1] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2013] [Accepted: 04/08/2014] [Indexed: 01/03/2023]
Abstract
Alcohol exposure can reduce adult proliferation and/or neurogenesis, but its impact on the ultimate neurogenic precursors, neural stem cells (NSCs), has been poorly addressed. Accordingly, the impact of voluntary consumption of alcohol on NSCs in the subventricular zone (SVZ) of the lateral ventricle was examined in this study. The NSC population in adult male C57BL/6J mice was measured after voluntary alcohol exposure in a two-bottle choice task using the neurosphere assay, while the number of NSCs that had proliferated 2 weeks prior to tissue collection was indexed using bromodeoxyuridine (BrdU) retention. There was a significant decrease in the number of BrdU-retaining cells in alcohol-consuming mice compared with controls, but no difference in the number of neurosphere-forming cells that could be derived from the SVZ of alcohol-consuming mice compared with controls. Additionally, PCNA-labeled cells in the SVZ tended to be lower, but there was no difference in BrdU labeling in the dentate gyrus following alcohol exposure. To determine alcohol's direct impact on NSCs and their progeny, neurospheres derived from naïve mice were treated with alcohol in vitro. Neurosphere formation was reduced by 100 mM alcohol without reducing cell viability. These findings are the first to assess the impact of moderate voluntary alcohol consumption on selective measures of adult NSCs and indicate that such exposure alters NSC proliferation dynamics in vivo and alcohol has direct but dissociable effects on the expansion and viability on NSCs and their progeny in vitro.
Collapse
|
216
|
Page KC, Jones EK, Anday EK. Maternal and postweaning high-fat diets disturb hippocampal gene expression, learning, and memory function. Am J Physiol Regul Integr Comp Physiol 2014; 306:R527-37. [DOI: 10.1152/ajpregu.00319.2013] [Citation(s) in RCA: 71] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
We tested the hypothesis that excess saturated fat consumption during pregnancy, lactation, and/or postweaning alters the expression of genes mediating hippocampal synaptic efficacy and impairs spatial learning and memory in adulthood. Dams were fed control chow or a diet high in saturated fat before mating, during pregnancy, and into lactation. Offspring were weaned to either standard chow or a diet high in saturated fat. The Morris Water Maze was used to evaluate spatial learning and memory. Open field testing was used to evaluate motor activity. Hippocampal gene expression in adult males was measured using RT-PCR and ELISA. Offspring from high fat-fed dams took longer, swam farther, and faster to try and find the hidden platform during the 5-day learning period. Control offspring consuming standard chow spent the most time in memory quadrant during the probe test. Offspring from high fat-fed dams consuming excess saturated fat spent the least. The levels of mRNA and protein for brain-derived neurotrophic factor and activity-regulated cytoskeletal-associated protein were significantly decreased by maternal diet effects. Nerve growth factor mRNA and protein levels were significantly reduced in response to both maternal and postweaning high-fat diets. Expression levels for the N-methyl-d-aspartate receptor (NMDA) receptor subunit NR2B as well as synaptophysin were significantly decreased in response to both maternal and postweaning diets. Synaptotagmin was significantly increased in offspring from high fat-fed dams. These data support the hypothesis that exposure to excess saturated fat during hippocampal development is associated with complex patterns of gene expression and deficits in learning and memory.
Collapse
Affiliation(s)
- Kathleen C. Page
- Biology Department, Bucknell University, Lewisburg, Pennsylvania; and
| | | | - Endla K. Anday
- Pediatrics, Drexel University College of Medicine, Philadelphia, Pennsylvania
| |
Collapse
|
217
|
The neurobiological pathogenesis of poststroke depression. ScientificWorldJournal 2014; 2014:521349. [PMID: 24744682 PMCID: PMC3973123 DOI: 10.1155/2014/521349] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2013] [Accepted: 01/28/2014] [Indexed: 12/14/2022] Open
Abstract
Poststroke depression (PSD) is an important consequence after stroke, with negative impact on stroke outcome. The pathogenesis of PSD is complicated, with some special neurobiological mechanism, which mainly involves neuroanatomical, neuron, and biochemical factors and neurogenesis which interact in complex ways. Abundant studies suggested that large lesions in critical areas such as left frontal lobe and basal ganglia or accumulation of silent cerebral lesions might interrupt the pathways of monoamines or relevant pathways of mood control, thus leading to depression. Activation of immune system after stroke produces more cytokines which increase glutamate excitotoxicity, results in more cell deaths of critical areas and enlargement of infarctions, and, together with hypercortisolism induced by stress or inflammation after stroke which could decrease intracellular serotonin transporters, might be the key biochemical change of PSD. The interaction among cytokines, glucocorticoid, and neurotrophin results in the decrease of hippocampal neurogenesis which has been proved to be important for mood control and pharmaceutical effect of selective serotonin reuptake inhibitors and might be another promising pathway to understand the pathogenesis of PSD. In order to reduce the prevalence of PSD and improve the outcome of stroke, more relevant studies are still required to clarify the pathogenesis of PSD.
Collapse
|
218
|
Saaltink DJ, Vreugdenhil E. Stress, glucocorticoid receptors, and adult neurogenesis: a balance between excitation and inhibition? Cell Mol Life Sci 2014; 71:2499-515. [PMID: 24522255 PMCID: PMC4055840 DOI: 10.1007/s00018-014-1568-5] [Citation(s) in RCA: 85] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2013] [Revised: 12/26/2013] [Accepted: 01/16/2014] [Indexed: 02/06/2023]
Abstract
Adult neurogenesis, the birth of new neurons in the mature brain, has attracted considerable attention in the last decade. One of the earliest identified and most profound factors that affect adult neurogenesis both positively and negatively is stress. Here, we review the complex interplay between stress and adult neurogenesis. In particular, we review the role of the glucocorticoid receptor, the main mediator of the stress response in the proliferation, differentiation, migration, and functional integration of newborn neurons in the hippocampus. We review a multitude of mechanisms regulating glucocorticoid receptor activity in relationship to adult neurogenesis. We postulate a novel concept in which the level of glucocorticoid receptor expression directly regulates the excitation-inhibition balance, which is key for proper neurogenesis. We furthermore argue that an excitation-inhibition dis-balance may underlie aberrant functional integration of newborn neurons that is associated with psychiatric and paroxysmal brain disorders.
Collapse
Affiliation(s)
- Dirk-Jan Saaltink
- Department of Medical Pharmacology, Leiden University Medical Center/Leiden Amsterdam Center for Drug Research, 2300 RC, Leiden, The Netherlands
| | | |
Collapse
|
219
|
Walker FR, Jones KA, Patience MJ, Zhao Z, Nilsson M. Stress as necessary component of realistic recovery in animal models of experimental stroke. J Cereb Blood Flow Metab 2014; 34:208-14. [PMID: 24326386 PMCID: PMC3915218 DOI: 10.1038/jcbfm.2013.211] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/01/2013] [Revised: 10/25/2013] [Accepted: 10/31/2013] [Indexed: 11/09/2022]
Abstract
Over the last decade there has been a considerable effort directed toward reformulating the standard approach taken to preclinically model stroke and stroke recovery. The principal objective of this undertaking has been to improve the success with which preclinical findings can be translated. Although several advancements have already been introduced, one potentially critical feature that appears to have been overlooked is psychological stress. Stroke is well recognized to produce high levels of stress in patients, and ongoing exposure to stress is recognized to deleteriously interfere with recovery. The presence of high levels of stress (distress) in stroke patients is also relevant because nearly all clinically deployed neurorestorative interventions occur against this background. Somewhat perplexingly, however, we could find no preclinical stroke studies concerned with investigating the efficacy of putative neurorestorative compounds that did so in the presence of stress. The following article will make the case that failure to recognize or compensate for the effects of ongoing stress in standard preclinical experimental models of recovery is likely to result in overestimation of the effectiveness of pharmacological or behavioral neurorestorative interventions.
Collapse
Affiliation(s)
- Frederick R Walker
- 1] School of Biomedical Sciences and Pharmacy, University of Newcastle, Callaghan, New South Wales, Australia [2] Centre for Translational Neuroscience, Mental Health Research, University of Newcastle, Callaghan, New South Wales, Australia [3] Hunter Medical Research Institute, Lot 1 Kookaburra Circuit, New Lambton Heights, New South Wales, Australia
| | - Kimberley A Jones
- 1] School of Biomedical Sciences and Pharmacy, University of Newcastle, Callaghan, New South Wales, Australia [2] Centre for Translational Neuroscience, Mental Health Research, University of Newcastle, Callaghan, New South Wales, Australia [3] Hunter Medical Research Institute, Lot 1 Kookaburra Circuit, New Lambton Heights, New South Wales, Australia
| | - Madeleine J Patience
- 1] School of Biomedical Sciences and Pharmacy, University of Newcastle, Callaghan, New South Wales, Australia [2] Centre for Translational Neuroscience, Mental Health Research, University of Newcastle, Callaghan, New South Wales, Australia [3] Hunter Medical Research Institute, Lot 1 Kookaburra Circuit, New Lambton Heights, New South Wales, Australia
| | - Zidan Zhao
- 1] School of Biomedical Sciences and Pharmacy, University of Newcastle, Callaghan, New South Wales, Australia [2] Centre for Translational Neuroscience, Mental Health Research, University of Newcastle, Callaghan, New South Wales, Australia [3] Hunter Medical Research Institute, Lot 1 Kookaburra Circuit, New Lambton Heights, New South Wales, Australia
| | - Michael Nilsson
- 1] Centre for Translational Neuroscience, Mental Health Research, University of Newcastle, Callaghan, New South Wales, Australia [2] Hunter Medical Research Institute, Lot 1 Kookaburra Circuit, New Lambton Heights, New South Wales, Australia
| |
Collapse
|
220
|
Grégoire CA, Bonenfant D, Le Nguyen A, Aumont A, Fernandes KJL. Untangling the influences of voluntary running, environmental complexity, social housing and stress on adult hippocampal neurogenesis. PLoS One 2014; 9:e86237. [PMID: 24465980 PMCID: PMC3900491 DOI: 10.1371/journal.pone.0086237] [Citation(s) in RCA: 79] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2013] [Accepted: 12/10/2013] [Indexed: 01/08/2023] Open
Abstract
Environmental enrichment (EE) exerts powerful effects on brain physiology, and is widely used as an experimental and therapeutic tool. Typical EE paradigms are multifactorial, incorporating elements of physical exercise, environmental complexity, social interactions and stress, however the specific contributions of these variables have not been separable using conventional housing paradigms. Here, we evaluated the impacts of these individual variables on adult hippocampal neurogenesis by using a novel "Alternating EE" paradigm. For 4 weeks, adult male CD1 mice were alternated daily between two enriched environments; by comparing groups that differed in one of their two environments, the individual and combinatorial effects of EE variables could be resolved. The Alternating EE paradigm revealed that (1) voluntary running for 3 days/week was sufficient to increase both mitotic and post-mitotic stages of hippocampal neurogenesis, confirming the central importance of exercise; (2) a complex environment (comprised of both social interactions and rotated inanimate objects) had no effect on neurogenesis itself, but enhanced depolarization-induced c-Fos expression (attributable to social interactions) and buffered stress-induced plasma corticosterone levels (attributable to inanimate objects); and (3) neither social isolation, group housing, nor chronically increased levels of plasma corticosterone had a prolonged impact on neurogenesis. Mouse strain, handling and type of running apparatus were tested and excluded as potential confounding factors. These findings provide valuable insights into the relative effects of key EE variables on adult neurogenesis, and this "Alternating EE" paradigm represents a useful tool for exploring the contributions of individual EE variables to mechanisms of neural plasticity.
Collapse
Affiliation(s)
- Catherine-Alexandra Grégoire
- Department of Pathology and Cell Biology, Groupe de recherche sur le système nerveux central (GRSNC), and Center of Excellence in Neuroscience of the Université de Montréal (CENUM), Université de Montréal, Montréal, Canada
| | - David Bonenfant
- Department of Pathology and Cell Biology, Groupe de recherche sur le système nerveux central (GRSNC), and Center of Excellence in Neuroscience of the Université de Montréal (CENUM), Université de Montréal, Montréal, Canada
| | - Adalie Le Nguyen
- Department of Pathology and Cell Biology, Groupe de recherche sur le système nerveux central (GRSNC), and Center of Excellence in Neuroscience of the Université de Montréal (CENUM), Université de Montréal, Montréal, Canada
| | - Anne Aumont
- Department of Pathology and Cell Biology, Groupe de recherche sur le système nerveux central (GRSNC), and Center of Excellence in Neuroscience of the Université de Montréal (CENUM), Université de Montréal, Montréal, Canada
| | - Karl J. L. Fernandes
- Department of Pathology and Cell Biology, Groupe de recherche sur le système nerveux central (GRSNC), and Center of Excellence in Neuroscience of the Université de Montréal (CENUM), Université de Montréal, Montréal, Canada
| |
Collapse
|
221
|
Maine AR, Powers SD, Lutterschmidt DI. Seasonal Variation in Cell Proliferation and Cell Migration in the Brain of Adult Red-Sided Garter Snakes(Thamnophis sirtalis parietalis). BRAIN, BEHAVIOR AND EVOLUTION 2014; 84:181-96. [DOI: 10.1159/000364778] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/18/2013] [Accepted: 12/13/2013] [Indexed: 11/19/2022]
|
222
|
Lucassen PJ, Pruessner J, Sousa N, Almeida OFX, Van Dam AM, Rajkowska G, Swaab DF, Czéh B. Neuropathology of stress. Acta Neuropathol 2014; 127:109-35. [PMID: 24318124 PMCID: PMC3889685 DOI: 10.1007/s00401-013-1223-5] [Citation(s) in RCA: 280] [Impact Index Per Article: 28.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2013] [Accepted: 11/26/2013] [Indexed: 02/06/2023]
Abstract
Environmental challenges are part of daily life for any individual. In fact, stress appears to be increasingly present in our modern, and demanding, industrialized society. Virtually every aspect of our body and brain can be influenced by stress and although its effects are partly mediated by powerful corticosteroid hormones that target the nervous system, relatively little is known about when, and how, the effects of stress shift from being beneficial and protective to becoming deleterious. Decades of stress research have provided valuable insights into whether stress can directly induce dysfunction and/or pathological alterations, which elements of stress exposure are responsible, and which structural substrates are involved. Using a broad definition of pathology, we here review the “neuropathology of stress” and focus on structural consequences of stress exposure for different regions of the rodent, primate and human brain. We discuss cytoarchitectural, neuropathological and structural plasticity measures as well as more recent neuroimaging techniques that allow direct monitoring of the spatiotemporal effects of stress and the role of different CNS structures in the regulation of the hypothalamic–pituitary–adrenal axis in human brain. We focus on the hypothalamus, hippocampus, amygdala, nucleus accumbens, prefrontal and orbitofrontal cortex, key brain regions that not only modulate emotions and cognition but also the response to stress itself, and discuss disorders like depression, post-traumatic stress disorder, Cushing syndrome and dementia.
Collapse
|
223
|
Repetitive noxious neonatal stimuli increases dentate gyrus cell proliferation and hippocampal brain-derived neurotrophic factor levels. Hippocampus 2013; 24:415-23. [DOI: 10.1002/hipo.22235] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2013] [Revised: 11/22/2013] [Accepted: 12/02/2013] [Indexed: 01/15/2023]
|
224
|
Castilla-Ortega E, Rosell-Valle C, Pedraza C, Rodríguez de Fonseca F, Estivill-Torrús G, Santín LJ. Voluntary exercise followed by chronic stress strikingly increases mature adult-born hippocampal neurons and prevents stress-induced deficits in 'what-when-where' memory. Neurobiol Learn Mem 2013; 109:62-73. [PMID: 24333647 DOI: 10.1016/j.nlm.2013.12.001] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2013] [Revised: 11/22/2013] [Accepted: 12/03/2013] [Indexed: 10/25/2022]
Abstract
We investigated whether voluntary exercise prevents the deleterious effects of chronic stress on episodic-like memory and adult hippocampal neurogenesis. After bromodeoxyuridine (BrdU) administration, mice were assigned to receive standard housing, chronic intermittent restraint stress, voluntary exercise or a combination of both (stress starting on the seventh day of exercise). Twenty-four days later, mice were tested in a 'what-when-where' object recognition memory task. Adult hippocampal neurogenesis (proliferation, differentiation, survival and apoptosis) and c-Fos expression in the hippocampus and extra-hippocampal areas (medial prefrontal cortex, amygdala, paraventricular hypothalamic nucleus, accumbens and perirhinal cortex) were assessed after behavior. Chronic intermittent restraint stress impaired neurogenesis and the 'when' memory, while exercise promoted neurogenesis and improved the 'where' memory. The 'when' and 'where' memories correlated with c-Fos expression in CA1 and the dentate gyrus, respectively. Furthermore, analysis suggested that each treatment induced a distinct pattern of functional connectivity among the areas analyzed for c-Fos. In the animals in which stress and exercise were combined, stress notably reduced the amount of voluntary exercise performed. Nevertheless, exercise still improved memory and counteracted the stress induced-deficits in neurogenesis and behavior. Interestingly, compared with the other three treatments, the stressed exercising animals showed a larger increase in cell survival, the maturation of new neurons and apoptosis in the dentate gyrus, with a considerable increase in the number of 24-day-old BrdU+cells that differentiated into mature neurons. The interaction between exercise and stress in enhancing the number of adult-born hippocampal neurons supports a role of exercise-induced neurogenesis in stressful conditions.
Collapse
Affiliation(s)
- Estela Castilla-Ortega
- Unidad de Gestión Clínica de Salud Mental, Hospital Regional Universitario Carlos Haya, Instituto de Investigación Biomédica de Málaga (IBIMA), Spain.
| | - Cristina Rosell-Valle
- Departamento de Psicobiología y Metodología de las Ciencias del Comportamiento, Universidad de Málaga, and Instituto de Investigación Biomédica de Málaga (IBIMA), E-29071 Málaga, Spain
| | - Carmen Pedraza
- Departamento de Psicobiología y Metodología de las Ciencias del Comportamiento, Universidad de Málaga, and Instituto de Investigación Biomédica de Málaga (IBIMA), E-29071 Málaga, Spain
| | - Fernando Rodríguez de Fonseca
- Unidad de Gestión Clínica de Salud Mental, Hospital Regional Universitario Carlos Haya, Instituto de Investigación Biomédica de Málaga (IBIMA), Spain
| | - Guillermo Estivill-Torrús
- Unidad de Microscopía and Unidad de Gestión Clínica de Neurociencias, Hospital Regional Universitario Carlos Haya, Instituto de Investigación Biomédica de Málaga (IBIMA), E-29009 Málaga, Spain
| | - Luis J Santín
- Departamento de Psicobiología y Metodología de las Ciencias del Comportamiento, Universidad de Málaga, and Instituto de Investigación Biomédica de Málaga (IBIMA), E-29071 Málaga, Spain.
| |
Collapse
|
225
|
Babic S, Jezova D. Effect of phenytoin treatment on cell proliferation in the hippocampus and the heart and related neuroendocrine changes under non-stress and stress conditions. Neurol Res 2013; 36:112-7. [DOI: 10.1179/1743132813y.0000000278] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
|
226
|
Maldonado JR. Neuropathogenesis of delirium: review of current etiologic theories and common pathways. Am J Geriatr Psychiatry 2013; 21:1190-222. [PMID: 24206937 DOI: 10.1016/j.jagp.2013.09.005] [Citation(s) in RCA: 402] [Impact Index Per Article: 36.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/23/2012] [Revised: 09/10/2013] [Accepted: 09/13/2013] [Indexed: 12/20/2022]
Abstract
Delirium is a neurobehavioral syndrome caused by dysregulation of neuronal activity secondary to systemic disturbances. Over time, a number of theories have been proposed in an attempt to explain the processes leading to the development of delirium. Each proposed theory has focused on a specific mechanism or pathologic process (e.g., dopamine excess or acetylcholine deficiency theories), observational and experiential evidence (e.g., sleep deprivation, aging), or empirical data (e.g., specific pharmacologic agents' association with postoperative delirium, intraoperative hypoxia). This article represents a review of published literature and summarizes the top seven proposed theories and their interrelation. This review includes the "neuroinflammatory," "neuronal aging," "oxidative stress," "neurotransmitter deficiency," "neuroendocrine," "diurnal dysregulation," and "network disconnectivity" hypotheses. Most of these theories are complementary, rather than competing, with many areas of intersection and reciprocal influence. The literature suggests that many factors or mechanisms included in these theories lead to a final common outcome associated with an alteration in neurotransmitter synthesis, function, and/or availability that mediates the complex behavioral and cognitive changes observed in delirium. In general, the most commonly described neurotransmitter changes associated with delirium include deficiencies in acetylcholine and/or melatonin availability; excess in dopamine, norepinephrine, and/or glutamate release; and variable alterations (e.g., either a decreased or increased activity, depending on delirium presentation and cause) in serotonin, histamine, and/or γ-aminobutyric acid. In the end, it is unlikely that any one of these theories is fully capable of explaining the etiology or phenomenologic manifestations of delirium but rather that two or more of these, if not all, act together to lead to the biochemical derangement and, ultimately, to the complex cognitive and behavioral changes characteristic of delirium.
Collapse
Affiliation(s)
- José R Maldonado
- Departments of Psychiatry, Internal Medicine & Surgery and the Psychosomatic Medicine Service, Stanford University School of Medicine, and Board of Directors, American Delirium Society, Stanford, CA.
| |
Collapse
|
227
|
Allen KM, Fung SJ, Rothmond DA, Noble PL, Weickert CS. Gonadectomy increases neurogenesis in the male adolescent rhesus macaque hippocampus. Hippocampus 2013; 24:225-38. [PMID: 24123729 DOI: 10.1002/hipo.22217] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2013] [Revised: 09/16/2013] [Accepted: 09/25/2013] [Indexed: 11/07/2022]
Abstract
New neurons are continuously produced in the subgranular zone of the adult hippocampus and can modulate hippocampal plasticity across life. Adolescence is characterized by dramatic changes in sex hormone levels, and social and emotional behaviors. It is also an age for increased risk of psychiatric disorders, including schizophrenia, which may involve altered hippocampal neurogenesis. The extent to which testosterone and other testicular hormones modulate hippocampal neurogenesis and adolescent behavioral development is unclear. This study aimed to determine if removal of testicular hormones during adolescence alters neurogenesis in the male rhesus macaque hippocampus. We used stereology to examine levels of cell proliferation, cell survival and neuronal differentiation in late adolescent male rhesus macaques (4.6-yrs old) that had previously been gonadectomized or sham operated prior to puberty (2.4-yrs old). While the absence of adolescent testicular hormones had no effect on cell proliferation, cell survival was increased by 65% and indices of immature neuronal differentiation were increased by 56% in gonadectomized monkeys compared to intact monkeys. We show for the first time that presence of circulating testicular hormones, including testosterone, may decrease neuronal survival in the primate hippocampus during adolescence. Our findings are in contrast to existing studies in adults where testosterone tends to be a pro-survival factor and demonstrate that testicular hormones may reduce hippocampal neurogenesis during the age typical of schizophrenia onset.
Collapse
Affiliation(s)
- K M Allen
- Schizophrenia Research Institute, Sydney, 2010, Australia; Schizophrenia Research Laboratory, Neuroscience Research Australia, Randwick, 2031, Australia; School of Psychiatry, University of New South Wales, Sydney, 2052, Australia
| | | | | | | | | |
Collapse
|
228
|
Kim HJ, Cho CW, Hwang JT, Son N, Choi JH, Shim GS, Han CK. LC-MS-based metabolomic analysis of serum and livers from red ginseng-fed rats. J Ginseng Res 2013; 37:371-8. [PMID: 24198664 PMCID: PMC3818965 DOI: 10.5142/jgr.2013.37.371] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2012] [Revised: 03/14/2013] [Accepted: 03/14/2013] [Indexed: 12/18/2022] Open
Abstract
Serum and liver metabolites in rats fed red ginseng (RG) were analyzed by ultra-performance liquid chromatography-quadrupole time-of-flight mass spectrometry. The mass data were analyzed by partial least squares-discriminant analysis (PLS-DA) to discriminate between control and RG groups and identify metabolites contributing to this discrimination. The RG group was clearly separated from the control group on PLS-DA scores plot for serum samples, but not liver samples. The major metabolites contributing to the discrimination included lipid metabolites (lysophosphatidylcholine, acyl-carnitine, and sphingosine), isoleucine, nicotinamide, and corticosterone in the serum; the blood levels of all but isoleucine were reduced by RG administration. Not all metabolites were positively correlated with the health benefits of RG. However, the blood levels of lysophosphatidylcholine, which stimulate various diseases, and long-chain acylcarnitines and corticosterone, which activate the stress response, were reduced by RG, suggesting long-term RG might relieve stress and prevent physiological and biological problems.
Collapse
Affiliation(s)
- Hyun-Jin Kim
- Division of Metabolism and Functionality Research, Korea Food Research Institute, Seongnam 463-746, Korea ; Division of Applied Life Science, Department of Food Science and Technology, Institue of Agriculture and Life Science, Gyeongsang National University, Jinju 660-701, Korea
| | | | | | | | | | | | | |
Collapse
|
229
|
McClintick JN, Xuei X, Tischfield JA, Goate A, Foroud T, Wetherill L, Ehringer MA, Edenberg HJ. Stress-response pathways are altered in the hippocampus of chronic alcoholics. Alcohol 2013; 47:505-15. [PMID: 23981442 DOI: 10.1016/j.alcohol.2013.07.002] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2013] [Revised: 07/02/2013] [Accepted: 07/09/2013] [Indexed: 12/26/2022]
Abstract
The chronic high-level alcohol consumption seen in alcoholism leads to dramatic effects on the hippocampus, including decreased white matter, loss of oligodendrocytes and other glial cells, and inhibition of neurogenesis. Examining gene expression in post mortem hippocampal tissue from 20 alcoholics and 19 controls allowed us to detect differentially expressed genes that may play a role in the risk for alcoholism or whose expression is modified by chronic consumption of alcohol. We identified 639 named genes whose expression significantly differed between alcoholics and controls at a False Discovery Rate (FDR) ≤ 0.20; 52% of these genes differed by at least 1.2-fold. Differentially expressed genes included the glucocorticoid receptor and the related gene FK506 binding protein 5 (FKBP5), UDP glycosyltransferase 8 (UGT8), urea transporter (SLC14A1), zinc transporter (SLC39A10), Interleukin 1 receptor type 1 (IL1R1), thioredoxin interacting protein (TXNIP), and many metallothioneins. Pathways related to inflammation, hypoxia, and stress showed activation, and pathways that play roles in neurogenesis and myelination showed decreases. The cortisol pathway dysregulation and increased inflammation identified here are seen in other stress-related conditions such as depression and post-traumatic stress disorder and most likely play a role in addiction. Many of the detrimental effects on the hippocampus appear to be mediated through NF-κB signaling. Twenty-four of the differentially regulated genes were previously identified by genome-wide association studies of alcohol use disorders; this raises the potential interest of genes not normally associated with alcoholism, such as suppression of tumorigenicity 18 (ST18), BCL2-associated athanogene 3 (BAG3), and von Willebrand factor (VWF).
Collapse
|
230
|
Lima M, Malheiros J, Negrigo A, Tescarollo F, Medeiros M, Suchecki D, Tannús A, Guinsburg R, Covolan L. Sex-related long-term behavioral and hippocampal cellular alterations after nociceptive stimulation throughout postnatal development in rats. Neuropharmacology 2013; 77:268-76. [PMID: 24148811 DOI: 10.1016/j.neuropharm.2013.10.007] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2013] [Revised: 10/03/2013] [Accepted: 10/06/2013] [Indexed: 01/21/2023]
Abstract
Early noxious stimuli may alter the neurogenesis rate in the dentate gyrus and the behavioral repertoire of adult rats. This study evaluated the long-term effects of noxious stimulation, imposed in different phases of development, on nociceptive and anxiety-like behaviors, hippocampal activation, cell proliferation, hippocampal BDNF and plasma corticosterone levels in 40 day-old male and female adolescents. Noxious stimulation was induced by intra-plantar injection of Complete Freund's adjuvant (CFA), on postnatal days (P) 1 (group P1), 8 (P8) or 21 (P21). Control animals were not stimulated in any way. On P21 a subset of animals from each group received BrdU and was perfused on P40 for identification of proliferating cells in the granule cell layer of the dentate gyrus. Another subset of rats was subjected to behavioral testing on P40 and one week later, to magnetic resonance imaging (MRI) acquisition. Noxious stimulation evoked hypoalgesia in adolescents, mainly in females (P < 0.02), reflected by greater latency to withdraw the paw and less paw lickings in the hot plate test than controls (P < 0.001). It also resulted in more time spent in the open arms, e.g., less anxiety-like behavior than controls (P < 0.01), especially in females (P < 0.01, compared with males). Proliferative cell rate in the dentate gyrus was the highest in P8 males and females (P < 0.001), with males exhibiting more proliferation than females on P1 and P8, which was directly related to the hippocampal levels of BDNF and inversely related to plasma corticosterone. Sex differences were also detected in manganese-enhanced MRI signal, which was more prominent in P1 females than males (P < 0.01). This study represents the first step of investigation on the cellular basis of the sex-dependent long-term consequences of nociceptive stimuli in newborns.
Collapse
Affiliation(s)
- Márcia Lima
- Departamento de Fisiologia, Universidade Federal de São Paulo, São Paulo, SP 04023-062, Brazil
| | - Jackeline Malheiros
- Departamento de Fisiologia, Universidade Federal de São Paulo, São Paulo, SP 04023-062, Brazil; Centro de Imagens e Espectroscopia in vivo por Ressonância Magnética (CIERMag), Instituto de Física de São Carlos, Universidade de São Paulo (IFSC-USP), São Carlos 13566-590, Brazil
| | - Aline Negrigo
- Departamento de Fisiologia, Universidade Federal de São Paulo, São Paulo, SP 04023-062, Brazil
| | - Fabio Tescarollo
- Departamento de Fisiologia, Universidade Federal de São Paulo, São Paulo, SP 04023-062, Brazil
| | - Magda Medeiros
- Departamento de Ciências Fisiológicas, Universidade Federal Rural do Rio de Janeiro, Seropédica 23890-000, Brazil
| | - Deborah Suchecki
- Departamento de Psicobiologia, Universidade Federal de São Paulo, São Paulo 04023-062, Brazil
| | - Alberto Tannús
- Centro de Imagens e Espectroscopia in vivo por Ressonância Magnética (CIERMag), Instituto de Física de São Carlos, Universidade de São Paulo (IFSC-USP), São Carlos 13566-590, Brazil
| | - Ruth Guinsburg
- Disciplina de Pediatria Neonatal, Departamento de Pediatria, Universidade Federal de São Paulo, São Paulo 04023-062, Brazil
| | - Luciene Covolan
- Departamento de Fisiologia, Universidade Federal de São Paulo, São Paulo, SP 04023-062, Brazil.
| |
Collapse
|
231
|
Hryhorczuk C, Sharma S, Fulton SE. Metabolic disturbances connecting obesity and depression. Front Neurosci 2013; 7:177. [PMID: 24109426 PMCID: PMC3791387 DOI: 10.3389/fnins.2013.00177] [Citation(s) in RCA: 193] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2013] [Accepted: 09/16/2013] [Indexed: 12/14/2022] Open
Abstract
Obesity markedly increases the odds of developing depression. Depressed mood not only impairs motivation, quality of life and overall functioning but also increases the risks of obesity complications. Abdominal obesity is a better predictor of depression and anxiety risk than overall adipose mass. A growing amount of research suggests that metabolic abnormalities stemming from central obesity that lead to metabolic disease may also be responsible for the increased incidence of depression in obesity. As reviewed here, a higher mass of dysfunctional adipose tissue is associated with several metabolic disturbances that are either directly or indirectly implicated in the control of emotions and mood. To better comprehend the development of depression in obesity, this review pulls together select findings addressing the link between adiposity, diet and negative emotional states and discusses the evidence that alterations in glucocorticoids, adipose-derived hormones, insulin and inflammatory signaling that are characteristic of central obesity may be involved.
Collapse
Affiliation(s)
- Cecile Hryhorczuk
- Department of Nutrition, Faculty of Medicine, CRCHUM and Montreal Diabetes Research Center, Université de Montréal Montreal, QC, Canada
| | | | | |
Collapse
|
232
|
Negative regulation of TLX by IL-1β correlates with an inhibition of adult hippocampal neural precursor cell proliferation. Brain Behav Immun 2013; 33:7-13. [PMID: 23510989 DOI: 10.1016/j.bbi.2013.03.005] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/24/2013] [Revised: 02/27/2013] [Accepted: 03/07/2013] [Indexed: 11/23/2022] Open
Abstract
Adult hippocampal neurogenesis is modulated by a number of intrinsic and extrinsic factors including local signalling molecules, exercise, aging and inflammation. Inflammation is also a major contributor to several hippocampal-associated disorders. Interleukin-1beta (IL-1β) is the most predominant pro-inflammatory cytokine in the brain, and an increase in its concentration is known to decrease the proliferation of both embryonic and adult hippocampal neural precursor cells (NPCs). Recent research has focused on the role of nuclear receptors as intrinsic regulators of neurogenesis, and it is now established that the orphan nuclear receptor TLX is crucial in maintaining the NPC pool in neurogenic brain regions. To better understand the involvement of TLX in IL-1β-mediated effects on hippocampal NPC proliferation, we examined hippocampal NPC proliferation and TLX expression in response to IL-1β treatment in an adult rat hippocampal neurosphere culture system. We demonstrate that IL-1β reduced the proliferation of hippocampal NPCs and TLX expression in a dose and time-dependent manner and that co-treatment with IL-1β receptor antagonist or IL-1 receptor siRNA prevented these effects. We also report a dose-dependent effect of IL-1β on the composition of cell phenotypes in the culture and on expression of TLX in these cells. This study thus provides evidence of an involvement of TLX in IL-1β-induced changes in adult hippocampal neurogenesis, and offers mechanistic insight into disorders in which neuroinflammation and alterations in neurogenesis are characteristic features.
Collapse
|
233
|
Holtzman CW, Trotman HD, Goulding SM, Ryan AT, Macdonald AN, Shapiro DI, Brasfield JL, Walker EF. Stress and neurodevelopmental processes in the emergence of psychosis. Neuroscience 2013; 249:172-91. [PMID: 23298853 PMCID: PMC4140178 DOI: 10.1016/j.neuroscience.2012.12.017] [Citation(s) in RCA: 169] [Impact Index Per Article: 15.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2012] [Revised: 11/24/2012] [Accepted: 12/02/2012] [Indexed: 11/28/2022]
Abstract
The notion that stress plays a role in the etiology of psychotic disorders, especially schizophrenia, is longstanding. However, it is only in recent years that the potential neural mechanisms mediating this effect have come into sharper focus. The introduction of more sophisticated models of the interplay between psychosocial factors and brain function has expanded our opportunities for conceptualizing more detailed psychobiological models of stress in psychosis. Further, scientific advances in our understanding of adolescent brain development have shed light on a pivotal question that has challenged researchers; namely, why the first episode of psychosis typically occurs in late adolescence/young adulthood. In this paper, we begin by reviewing the evidence supporting associations between psychosocial stress and psychosis in diagnosed patients as well as individuals at clinical high risk for psychosis. We then discuss biological stress systems and examine changes that precede and follow psychosis onset. Next, research findings on structural and functional brain characteristics associated with psychosis are presented; these findings suggest that normal adolescent neuromaturational processes may go awry, thereby setting the stage for the emergence of psychotic syndromes. Finally, a model of neural mechanisms underlying the pathogenesis of psychosis is presented and directions for future research strategies are explored.
Collapse
Affiliation(s)
- C. W. Holtzman
- Department of Psychology, Emory University, 36 Eagle Row, Atlanta, GA 30322, United States
| | - H. D. Trotman
- Department of Psychology, Emory University, 36 Eagle Row, Atlanta, GA 30322, United States
| | - S. M. Goulding
- Department of Psychology, Emory University, 36 Eagle Row, Atlanta, GA 30322, United States
| | - A. T. Ryan
- Department of Psychology, Emory University, 36 Eagle Row, Atlanta, GA 30322, United States
| | - A. N. Macdonald
- Department of Psychology, Emory University, 36 Eagle Row, Atlanta, GA 30322, United States
| | - D. I. Shapiro
- Department of Psychology, Emory University, 36 Eagle Row, Atlanta, GA 30322, United States
| | - J. L. Brasfield
- Department of Psychology, Emory University, 36 Eagle Row, Atlanta, GA 30322, United States
| | - E. F. Walker
- Department of Psychology, Emory University, 36 Eagle Row, Atlanta, GA 30322, United States
| |
Collapse
|
234
|
Prenatal stress inhibits hippocampal neurogenesis but spares olfactory bulb neurogenesis. PLoS One 2013; 8:e72972. [PMID: 24009723 PMCID: PMC3756947 DOI: 10.1371/journal.pone.0072972] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2013] [Accepted: 07/16/2013] [Indexed: 12/29/2022] Open
Abstract
The dentate gyrus (DG) and the olfactory bulb (OB) are two regions of the adult brain in which new neurons are integrated daily in the existing networks. It is clearly established that these newborn neurons are implicated in specific functions sustained by these regions and that different factors can influence neurogenesis in both structures. Among these, life events, particularly occurring during early life, were shown to profoundly affect adult hippocampal neurogenesis and its associated functions like spatial learning, but data regarding their impact on adult bulbar neurogenesis are lacking. We hypothesized that prenatal stress could interfere with the development of the olfactory system, which takes place during the prenatal period, leading to alterations in adult bulbar neurogenesis and in olfactory capacities. To test this hypothesis we exposed pregnant C57Bl/6J mice to gestational restraint stress and evaluated behavioral and anatomic consequences in adult male offspring. We report that prenatal stress has no impact on adult bulbar neurogenesis, and does not alter olfactory functions in adult male mice. However, it decreases cell proliferation and neurogenesis in the DG of the hippocampus, thus confirming previous reports on rats. Altogether our data support a selective and cross-species long-term impact of prenatal stress on neurogenesis.
Collapse
|
235
|
Trotman HD, Holtzman CW, Ryan AT, Shapiro DI, MacDonald AN, Goulding SM, Brasfield JL, Walker EF. The development of psychotic disorders in adolescence: a potential role for hormones. Horm Behav 2013; 64:411-9. [PMID: 23998682 PMCID: PMC4070947 DOI: 10.1016/j.yhbeh.2013.02.018] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/02/2012] [Revised: 01/20/2013] [Accepted: 02/26/2013] [Indexed: 12/14/2022]
Abstract
This article is part of a Special Issue "Puberty and Adolescence". The notion that adolescence is characterized by dramatic changes in behavior, and often by emotional upheaval, is widespread and longstanding in popular western culture. In recent decades, this notion has gained increasing support from empirical research showing that the peri- and post-pubertal developmental stages are associated with a significant rise in the rate of psychiatric symptoms and syndromes. As a result, interest in adolescent development has burgeoned among researchers focused on the origins of schizophrenia and other psychotic disorders. Two factors have fueled this trend: 1) increasing evidence from longitudinal research that adolescence is the modal period for the emergence of "prodromal" manifestations, or precursors of psychotic symptoms, and 2) the rapidly accumulating scientific findings on brain structural and functional changes occurring during adolescence and young adulthood. Further, gonadal and adrenal hormones are beginning to play a more prominent role in conceptualizations of adolescent brain development, as well as in the origins of psychiatric symptoms during this period (Walker and Bollini, 2002; Walker et al., 2008). In this paper, we begin by providing an overview of the nature and course of psychotic disorders during adolescence/young adulthood. We then turn to the role of hormones in modulating normal brain development, and the potential role they might play in the abnormal brain changes that characterize youth at clinical high-risk (CHR) for psychosis. The activational and organizational effects of hormones are explored, with a focus on how hormone-induced changes might be linked with neuropathological processes in the emergence of psychosis.
Collapse
Affiliation(s)
- Hanan D Trotman
- Department of Psychology, Emory University, Atlanta, GA 30322, USA.
| | | | | | | | | | | | | | | |
Collapse
|
236
|
microRNAs and the regulation of neuronal plasticity under stress conditions. Neuroscience 2013; 241:188-205. [DOI: 10.1016/j.neuroscience.2013.02.065] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2012] [Revised: 02/26/2013] [Accepted: 02/26/2013] [Indexed: 12/21/2022]
|
237
|
Barker JM, Charlier TD, Ball GF, Balthazart J. A new method for in vitro detection of bromodeoxyuridine in serum: a proof of concept in a songbird species, the canary. PLoS One 2013; 8:e63692. [PMID: 23691086 PMCID: PMC3653834 DOI: 10.1371/journal.pone.0063692] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2012] [Accepted: 04/06/2013] [Indexed: 01/03/2023] Open
Abstract
Systemic injection of a thymidine analogue such as bromodeoxyuridine (BrdU) in vertebrates is commonly used to detect and study cell production during development, adulthood, and pathology, particularly in studies of adult neurogenesis. Although researchers are applying this technique to multiple species in various physiological conditions, the rate of BrdU clearance from the serum remains unknown in most cases. Changes in this clearance rate as a function of the species, sex or endocrine condition could however profoundly affect the interpretation of the results. We describe a rapid, sensitive, but simple bioassay for post-injection detection and quantification of BrdU in serum. This procedure was shown to be suitable for determining the length of time a thymidine analogue remains in the bloodstream of one avian species and seems applicable to any vertebrate provided sufficiently large blood samples can be collected. This technique was used to demonstrate that, in canaries, BrdU injected at a dose of 100 mg/kg is no longer available for incorporation into DNA between 30 and 60 min post-injection, a delay shorter than anticipated based on the available literature. Preliminary data suggest a similar fast clearance in Japanese quail and mice.
Collapse
Affiliation(s)
- Jennifer M Barker
- GIGA Neurosciences, Research Group in Behavioral Neuroendocrinology, University of Liege, Liege, Belgium
| | | | | | | |
Collapse
|
238
|
Effects of diabetes on hippocampal neurogenesis: links to cognition and depression. Neurosci Biobehav Rev 2013; 37:1346-62. [PMID: 23680701 DOI: 10.1016/j.neubiorev.2013.03.010] [Citation(s) in RCA: 159] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2012] [Revised: 03/11/2013] [Accepted: 03/14/2013] [Indexed: 12/29/2022]
Abstract
Diabetes often leads to a number of complications involving brain function, including cognitive decline and depression. In addition, depression is a risk factor for developing diabetes. A loss of hippocampal neuroplasticity, which impairs the ability of the brain to adapt and reorganize key behavioral and emotional functions, provides a framework for understanding this reciprocal relationship. The effects of diabetes on brain and behavioral functions in experimental models of type 1 and type 2 diabetes are reviewed, with a focus on the negative impact of impaired hippocampal neurogenesis, dendritic remodeling and increased apoptosis. Mechanisms shown to regulate neuroplasticity and behavior in diabetes models, including stress hormones, neurotransmitters, neurotrophins, inflammation and aging, are integrated within this framework. Pathological changes in hippocampal function can contribute to the brain symptoms of diabetes-associated complications by failing to regulate the hypothalamic-pituitary-axis, maintain learning and memory and govern emotional expression. Further characterization of alterations in neuroplasticity along with glycemic control will facilitate the development and evaluation of pharmacological interventions that could successfully prevent and/or reverse the detrimental effects of diabetes on brain and behavior.
Collapse
|
239
|
Glasper ER, Gould E. Sexual experience restores age-related decline in adult neurogenesis and hippocampal function. Hippocampus 2013; 23:303-12. [PMID: 23460298 PMCID: PMC9985342 DOI: 10.1002/hipo.22090] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/12/2012] [Indexed: 01/17/2023]
Abstract
Aging is associated with compromised hippocampal function and reduced adult neurogenesis in the dentate gyrus. As new neurons have been linked to hippocampal functions, such as cognition, age-related decline in new neuron formation may contribute to impaired hippocampal function. We investigated whether a rewarding experience known to stimulate neurogenesis in young adult rats, namely sexual experience, would restore new neuron production and hippocampal function in middle-aged rats. Sexual experience enhanced the number of newly generated neurons in the dentate gyrus with both single and repeated exposures in middle-aged rats. Following continuous long-term exposure to sexual experience, cognitive function was improved. However, when a prolonged withdrawal period was introduced between the final mating experience and behavioral testing, the improvements in cognitive function were lost despite the presence of more new neurons. Taken together, these results suggest that repeated sexual experience can stimulate adult neurogenesis and restore cognitive function in the middle-aged rat as long as the experience persists throughout the testing period. The extent to which changes in adult neurogenesis underlie those in cognition remain unknown.
Collapse
Affiliation(s)
- Erica R. Glasper
- University of Maryland, Department of Psychology, College Park, MD 20742, US
| | - Elizabeth Gould
- Princeton University, Department of Psychology and Neuroscience Institute, Princeton, NJ 08544, US,Corresponding author: Elizabeth Gould, Department of Psychology and Neuroscience, Institute, Princeton University, Princeton, NJ 08544, Telephone: 609-258-4483,
| |
Collapse
|
240
|
Hereditary catalepsy in mice is associated with the brain dysmorphology and altered stress response. Behav Brain Res 2013; 243:53-60. [DOI: 10.1016/j.bbr.2012.12.057] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2012] [Revised: 12/25/2012] [Accepted: 12/28/2012] [Indexed: 11/20/2022]
|
241
|
Luu P, Sill OC, Gao L, Becker S, Wojtowicz JM, Smith DM. The role of adult hippocampal neurogenesis in reducing interference. Behav Neurosci 2013; 126:381-91. [PMID: 22642883 DOI: 10.1037/a0028252] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Adult neurogenesis in the hippocampal dentate gyrus plays an important role in learning and memory. However, the precise contribution of the new neurons to hippocampal function remains controversial. Emerging evidence suggests that neurogenesis is important for pattern separation and for mitigating interference when similar items must be learned at different times. In the present study, we directly test this prediction using a recently developed olfactory memory task that has those specific features. In this task, rats learn two highly interfering lists of odor pairs, one after the other, in either the same or in different contexts. Consistent with our hypothesis, focal cranial irradiation, resulting in selective reduction of neurogenesis within the dentate gyrus, significantly impaired the ability to overcome interference during learning of the second list. The ability to learn a single odor list was unimpaired. We also show that irradiation had no effect on learning in a hippocampal-dependent spatial alternation task. Although both tasks involved learning interfering responses, the time course for learning the interfering items differed. Learning the interfering odor lists took place sequentially, over the course of several sessions, whereas learning the interfering spatial locations took place concurrently, within each session. Thus, the gradual addition of new neurons may have provided a pattern separation mechanism for the olfactory task but not for the maze task. These findings demonstrate a role for neurogenesis in resolving interference and they are consistent with models suggesting a critical role for neurogenesis in pattern separation.
Collapse
Affiliation(s)
- Paul Luu
- Department of Physiology, University of Toronto
| | | | | | | | | | | |
Collapse
|
242
|
Schloesser RJ, Jimenez DV, Hardy NF, Paredes D, Catlow BJ, Manji HK, McKay RD, Martinowich K. Atrophy of pyramidal neurons and increased stress-induced glutamate levels in CA3 following chronic suppression of adult neurogenesis. Brain Struct Funct 2013; 219:1139-48. [PMID: 23483239 DOI: 10.1007/s00429-013-0532-8] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2012] [Accepted: 02/21/2013] [Indexed: 01/12/2023]
Abstract
Following their birth in the adult hippocampal dentate gyrus, newborn progenitor cells migrate into the granule cell layer where they differentiate, mature, and functionally integrate into existing circuitry. The hypothesis that adult hippocampal neurogenesis is physiologically important has gained traction, but the precise role of newborn neurons in hippocampal function remains unclear. We investigated whether loss of new neurons impacts dendrite morphology and glutamate levels in area CA3 of the hippocampus by utilizing a human GFAP promoter-driven thymidine kinase genetic mouse model to conditionally suppress adult neurogenesis. We found that chronic ablation of new neurons induces remodeling in CA3 pyramidal cells and increases stress-induced release of the neurotransmitter glutamate. The ability of persistent impairment of adult neurogenesis to influence hippocampal dendrite morphology and excitatory amino acid neurotransmission has important implications for elucidating newborn neuron function, and in particular, understanding the role of these cells in stress-related excitoxicity.
Collapse
Affiliation(s)
- Robert J Schloesser
- Mood and Anxiety Disorders Program, National Institute of Mental Health (NIMH), National Institutes of Health (NIH), Bethesda, MD, 20892, USA
| | | | | | | | | | | | | | | |
Collapse
|
243
|
Meyer M, Gonzalez Deniselle MC, Gargiulo-Monachelli G, Lima A, Roig P, Guennoun R, Schumacher M, De Nicola AF. Progesterone attenuates several hippocampal abnormalities of the Wobbler mouse. J Neuroendocrinol 2013; 25:235-43. [PMID: 23157231 DOI: 10.1111/jne.12004] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/11/2012] [Revised: 09/03/2012] [Accepted: 11/10/2012] [Indexed: 12/13/2022]
Abstract
It is now recognised that progesterone plays a protective role for diseases of the central nervous system. In the Wobbler mouse, a model of motoneurone degeneration, progesterone treatment prevents spinal cord neuropathology and clinical progression of the disease. However, neuropathological and functional abnormalities have also been discovered in the brain of Wobbler mice and patients with amyotrophic lateral sclerosis. The present study examined the hippocampus of control and afflicted Wobbler mice and the changes in response to progesterone treatment. Mice received either a single progesterone implant (20 mg for 18 days). We found that the hippocampal pathology of the untreated Wobblers involved a decreased expression of brain-derived neurotrophic factor (BDNF) mRNA, decreased astrogliosis in the stratum lucidum, stratum radiatum and stratum lacunosum-moleculare, decreased doublecortin (DCX)-positive neuroblasts in the subgranular zone of the dentate gyrus and a decreased density of GABA immunoreactive hippocampal interneurones and granule cells of the dentate gyrus. Although progesterone did not change the normal parameters of control mice, it attenuated several hippocampal abnormalities in Wobblers. Thus, progesterone increased hippocampal BDNF mRNA expression, decreased glial fibrillary acidic protein-positive astrocytes and increased the number of GABAergic interneurones and granule cells. The number of DCX expressing neuroblasts and immature neurones remained impaired in both progesterone-treated and untreated Wobblers. In conclusion, progesterone treatment exerted beneficial effects on some aspects of hippocampal neuropathology, suggesting its neuroprotective role in the brain, in agreement with previous data obtained in the spinal cord of Wobbler mice.
Collapse
Affiliation(s)
- M Meyer
- Laboratory of Neuroendocrine Biochemistry, Instituto de Biología y Medicina Experimental-CONICET, Buenos Aires, Argentina
| | | | | | | | | | | | | | | |
Collapse
|
244
|
Castrén E, Hen R. Neuronal plasticity and antidepressant actions. Trends Neurosci 2013; 36:259-67. [PMID: 23380665 DOI: 10.1016/j.tins.2012.12.010] [Citation(s) in RCA: 146] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2012] [Revised: 12/27/2012] [Accepted: 12/28/2012] [Indexed: 01/22/2023]
Abstract
Antidepressant treatments enhance plasticity and increase neurogenesis in the adult brain, but it has been unclear how these effects influence mood. We propose that, like environmental enrichment and exercise, antidepressant treatments enhance adaptability by increasing structural variability within the nervous system at many levels, from proliferating precursors to immature synaptic contacts. Conversely, sensory deprivation and chronic stress reduce this structural variability. Activity-dependent competition within the mood-related circuits, guided by rehabilitation, then selects for the survival and stabilization of those structures that best represent the internal or external milieu. Increased variability together with competition-mediated selection facilitates normal function, such as pattern separation within the dentate gyrus and other mood-related circuits, thereby enhancing adaptability toward novel experiences.
Collapse
Affiliation(s)
- Eero Castrén
- Neuroscience Center, University of Helsinki, P.O. Box 56, 00014 Helsinki, Finland.
| | | |
Collapse
|
245
|
|
246
|
Malva JO, Xapelli S, Baptista S, Valero J, Agasse F, Ferreira R, Silva AP. Multifaces of neuropeptide Y in the brain--neuroprotection, neurogenesis and neuroinflammation. Neuropeptides 2012; 46:299-308. [PMID: 23116540 DOI: 10.1016/j.npep.2012.09.001] [Citation(s) in RCA: 92] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/01/2012] [Revised: 09/17/2012] [Accepted: 09/25/2012] [Indexed: 12/20/2022]
Abstract
Neuropeptide Y (NPY) has been implicated in the modulation of important features of neuronal physiology, including calcium homeostasis, neurotransmitter release and excitability. Moreover, NPY has been involved as an important modulator of hippocampal and thalamic circuits, receiving particular attention as an endogenous antiepileptic peptide and as a potential master regulator of feeding behavior. NPY not only inhibits excessive glutamate release (decreasing circuitry hyperexcitability) but also protects neurons from excitotoxic cell death. Furthermore, NPY has been involved in the modulation of the dynamics of dentate gyrus and subventricular zone neural stem cell niches. In both regions, NPY is part of the chemical resource of the neurogenic niche and acts through NPY Y1 receptors to promote neuronal differentiation. Interestingly, NPY is also considered a neuroimmune messenger. In this review, we highlight recent evidences concerning paracrine/autocrine actions of NPY involved in neuroprotection, neurogenesis and neuroinflammation. In summary, the three faces of NPY, discussed in the present review, may contribute to better understand the dynamics and cell fate decision in the brain parenchyma and in restricted areas of neurogenic niches, in health and disease.
Collapse
Affiliation(s)
- J O Malva
- Laboratory of Biochemistry and Cell Biology, Faculty of Medicine, University of Coimbra, Rua Larga, 3004-504 Coimbra, Portugal.
| | | | | | | | | | | | | |
Collapse
|
247
|
Arnold SA, Hagg T. Serotonin 1A receptor agonist increases species- and region-selective adult CNS proliferation, but not through CNTF. Neuropharmacology 2012; 63:1238-47. [PMID: 22884499 PMCID: PMC3438376 DOI: 10.1016/j.neuropharm.2012.07.047] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2011] [Revised: 07/13/2012] [Accepted: 07/27/2012] [Indexed: 01/06/2023]
Abstract
Endogenous ciliary neurotrophic factor (CNTF)(1) regulates neurogenesis of the adult brain in the hippocampal subgranular zone (SGZ)(2) and the subventricular zone (SVZ)(3). We have previously shown that the cAMP-inhibiting D2 dopamine receptor increases neurogenesis by inducing astroglial CNTF expression. Here, we investigated the potential role of CNTF in the proliferative response to pharmacological stimulation of the serotonin 1A (5-HT1A)(4) receptor, which also inhibits cAMP, in adult mice and rats. Like others, we show that systemic treatment with the active R-enantiomer of the 5-HT1A agonist 8-Hydroxy-2-(di-n-propylamino)tetralin (8-OH-DPAT)(5) induces proliferation in the SGZ in rats using unbiased stereology of 5-Bromo-2'-deoxyuridine (BrdU)(6) positive nuclei. However, despite the bioactivity of R-8-OH-DPAT, as also shown by a decrease in hippocampal nNOS(7) mRNA levels, it did not increase CNTF mRNA as shown by highly specific quantitative RT-PCR (qPCR)(8). Surprisingly, R-8-OH-DPAT did not cause an increase in SVZ proliferation in rats or in either the SVZ or SGZ of two different strains of mice, C57BL/6J, and 129SvEv, using acute or chronic treatments. There also were no changes in CNTF mRNA, and also not in mice treated with a widely used racemic mixture of 8-OH-DPAT, higher doses or after intracerebral injection, which reduced nNOS. In contrast to the others, we propose that the 5-HT1A receptor might be non-functional in mice with regards to regulating normal neurogenesis and has region-selective activities in rats. These species- and region-specific actions raise important questions about the role of the 5-HT1A receptor in human neurogenesis and its implications for the field of depression.
Collapse
Affiliation(s)
- Sheila A. Arnold
- Kentucky Spinal Cord Injury Research Center, University of Louisville, Kentucky 40292
- Departments of Neurological Surgery, University of Louisville, Kentucky 40292
| | - Theo Hagg
- Kentucky Spinal Cord Injury Research Center, University of Louisville, Kentucky 40292
- Departments of Neurological Surgery, University of Louisville, Kentucky 40292
- Pharmacology and Toxicology, University of Louisville, Kentucky 40292
| |
Collapse
|
248
|
Bachor TP, Suburo AM. Neural stem cells in the diabetic brain. Stem Cells Int 2012; 2012:820790. [PMID: 23213341 PMCID: PMC3505664 DOI: 10.1155/2012/820790] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2012] [Accepted: 10/15/2012] [Indexed: 01/28/2023] Open
Abstract
Experimental diabetes in rodents rapidly affects the neurogenic niches of the adult brain. Moreover, behavioral disorders suggest that a similar dysfunction of the neurogenic niches most likely affects diabetic and prediabetic patients. Here, we review our present knowledge about adult neural stem cells, the methods used for their study in diabetic models, and the effects of experimental diabetes. Variations in diet and even a short hyperglycemia profoundly change the structure and the proliferative dynamics of the neurogenic niches. Moreover, alterations of diabetic neurogenic niches appear to be associated with diabetic cognitive disorders. Available evidence supports the hypothesis that, in the adult, early changes of the neurogenic niches might enhance development of the diabetic disease.
Collapse
Affiliation(s)
| | - Angela M. Suburo
- Medicina Celular y Molecular, Facultad de Ciencias Biomédicas, Universidad Austral, Buenos Aires, B1629AHJ Pilar, Argentina
| |
Collapse
|
249
|
Castro OW, Santos VR, Pun RYK, McKlveen JM, Batie M, Holland KD, Gardner M, Garcia-Cairasco N, Herman JP, Danzer SC. Impact of corticosterone treatment on spontaneous seizure frequency and epileptiform activity in mice with chronic epilepsy. PLoS One 2012; 7:e46044. [PMID: 23029379 PMCID: PMC3460996 DOI: 10.1371/journal.pone.0046044] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2012] [Accepted: 08/27/2012] [Indexed: 12/28/2022] Open
Abstract
Stress is the most commonly reported precipitating factor for seizures in patients with epilepsy. Despite compelling anecdotal evidence for stress-induced seizures, animal models of the phenomena are sparse and possible mechanisms are unclear. Here, we tested the hypothesis that increased levels of the stress-associated hormone corticosterone (CORT) would increase epileptiform activity and spontaneous seizure frequency in mice rendered epileptic following pilocarpine-induced status epilepticus. We monitored video-EEG activity in pilocarpine-treated mice 24/7 for a period of four or more weeks, during which animals were serially treated with CORT or vehicle. CORT increased the frequency and duration of epileptiform events within the first 24 hours of treatment, and this effect persisted for up to two weeks following termination of CORT injections. Interestingly, vehicle injection produced a transient spike in CORT levels – presumably due to the stress of injection – and a modest but significant increase in epileptiform activity. Neither CORT nor vehicle treatment significantly altered seizure frequency; although a small subset of animals did appear responsive. Taken together, our findings indicate that treatment of epileptic animals with exogenous CORT designed to mimic chronic stress can induce a persistent increase in interictal epileptiform activity.
Collapse
Affiliation(s)
- Olagide W. Castro
- Department of Physiology, Ribeirão Preto School of Medicine, University of São Paulo, Ribeirão Preto, São Paulo, Brazil
| | - Victor R. Santos
- Department of Physiology, Ribeirão Preto School of Medicine, University of São Paulo, Ribeirão Preto, São Paulo, Brazil
| | - Raymund Y. K. Pun
- Department of Anesthesia, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, United States of America
| | - Jessica M. McKlveen
- Program in Neuroscience, University of Cincinnati, Cincinnati, Ohio, United States of America
- Department of Psychiatry and Behavioral Neuroscience, University of Cincinnati, Cincinnati, Ohio, United States of America
| | - Matthew Batie
- Division of Clinical Engineering, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, United States of America
| | - Katherine D. Holland
- Division of Neurology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, United States of America
| | - Margaret Gardner
- Molecular and Developmental Biology Program, University of Cincinnati, Cincinnati, Ohio, United States of America
| | - Norberto Garcia-Cairasco
- Department of Physiology, Ribeirão Preto School of Medicine, University of São Paulo, Ribeirão Preto, São Paulo, Brazil
| | - James P. Herman
- Program in Neuroscience, University of Cincinnati, Cincinnati, Ohio, United States of America
- Department of Psychiatry and Behavioral Neuroscience, University of Cincinnati, Cincinnati, Ohio, United States of America
| | - Steve C. Danzer
- Program in Neuroscience, University of Cincinnati, Cincinnati, Ohio, United States of America
- Department of Anesthesia, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, United States of America
- Molecular and Developmental Biology Program, University of Cincinnati, Cincinnati, Ohio, United States of America
- Departments of Anesthesia and Pediatrics, University of Cincinnati, Cincinnati, Ohio, United States of America
- * E-mail:
| |
Collapse
|
250
|
Hu P, Oomen C, van Dam AM, Wester J, Zhou JN, Joëls M, Lucassen PJ. A single-day treatment with mifepristone is sufficient to normalize chronic glucocorticoid induced suppression of hippocampal cell proliferation. PLoS One 2012; 7:e46224. [PMID: 23049985 PMCID: PMC3458013 DOI: 10.1371/journal.pone.0046224] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2012] [Accepted: 08/28/2012] [Indexed: 01/06/2023] Open
Abstract
Background Chronic stress or prolonged administration of glucocorticoids suppresses proliferation and/or survival of newborn cells in adult rat dentate gyrus. Earlier we showed that administration of the glucocorticoid receptor antagonist mifepristone during the final 4 days of a 21 days period of corticosterone treatment fully normalized the number of newborn cells. Here we aimed to better understand how mifepristone achieves this effect and questioned whether an even shorter (single day) mifepristone treatment (instead of 4 days) also suffices to normalize neurogenesis. Methods We investigated various steps of the neurogenic process, using the immunohistochemical markers BrdU, doublecortin, proliferating cell nuclear antigen as well as glial fibrillary acidic protein, after 17 or 21 days of corticosterone (versus vehicle) treatment. Results Corticosterone primarily attenuates the proliferation of cells which subsequently develop into neurons; this is fully reversed by mifepristone. Surprisingly, the corticosteroid effects on neurogenesis can even be fully re-set by a single-day treatment with mifepristone (on day 18), despite the continued corticosterone exposure on subsequent days. Conclusions Our results emphasize that studies into the therapeutical efficacy of new antidepressants, especially those targeting HPA-activity or the glucocorticoid receptor, should explore the possibility to reduce treatment duration.
Collapse
Affiliation(s)
- Pu Hu
- Swammerdam Institute for Life Sciences, Center for Neuroscience, University of Amsterdam, Amsterdam, The Netherlands
- CAS Key Laboratory of Brain Function and Diseases, School of Life Science, University of Science and Technology of China, Hefei, Anhui, China
| | - Charlotte Oomen
- Swammerdam Institute for Life Sciences, Center for Neuroscience, University of Amsterdam, Amsterdam, The Netherlands
| | - Anne-Marie van Dam
- VU University Medical Center, Neuroscience Campus Amsterdam, Department of Anatomy and Neurosciences, Amsterdam, The Netherlands
| | - Jordi Wester
- Swammerdam Institute for Life Sciences, Center for Neuroscience, University of Amsterdam, Amsterdam, The Netherlands
| | - Jiang-Ning Zhou
- CAS Key Laboratory of Brain Function and Diseases, School of Life Science, University of Science and Technology of China, Hefei, Anhui, China
| | - Marian Joëls
- Swammerdam Institute for Life Sciences, Center for Neuroscience, University of Amsterdam, Amsterdam, The Netherlands
- Rudolf Magnus Institute for Neurosciences, Department of Neuroscience and Pharmacology, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Paul J. Lucassen
- Swammerdam Institute for Life Sciences, Center for Neuroscience, University of Amsterdam, Amsterdam, The Netherlands
- * E-mail:
| |
Collapse
|