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McEwen BS, Morrison JH. The brain on stress: vulnerability and plasticity of the prefrontal cortex over the life course. Neuron 2013; 79:16-29. [PMID: 23849196 DOI: 10.1016/j.neuron.2013.06.028] [Citation(s) in RCA: 665] [Impact Index Per Article: 55.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/20/2013] [Indexed: 12/14/2022]
Abstract
The prefrontal cortex (PFC) is involved in working memory and self-regulatory and goal-directed behaviors and displays remarkable structural and functional plasticity over the life course. Neural circuitry, molecular profiles, and neurochemistry can be changed by experiences, which influence behavior as well as neuroendocrine and autonomic function. Such effects have a particular impact during infancy and in adolescence. Behavioral stress affects both the structure and function of PFC, though such effects are not necessarily permanent, as young animals show remarkable neuronal resilience if the stress is discontinued. During aging, neurons within the PFC become less resilient to stress. There are also sex differences in the PFC response to stressors. While such stress and sex hormone-related alterations occur in regions mediating the highest levels of cognitive function and self-regulatory control, the fact that they are not necessarily permanent has implications for future behavior-based therapies that harness neural plasticity for recovery.
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Affiliation(s)
- Bruce S McEwen
- Laboratory of Neuroendocrinology, The Rockefeller University, 1230 York Avenue, New York, NY 10065, USA.
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202
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Glucocorticoid receptors in the prefrontal cortex regulate dopamine efflux to stress via descending glutamatergic feedback to the ventral tegmental area. Int J Neuropsychopharmacol 2013; 16:1799-807. [PMID: 23590841 DOI: 10.1017/s1461145713000187] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Enhanced dopamine (DA) efflux in the medial prefrontal cortex (mPFC) is a well-documented response to acute stress. We have previously shown that glucocorticoid receptors in the mPFC regulate stress-evoked DA efflux but the underlying mechanism is unknown. DA neurons in the ventral tegmental area (VTA) receive excitatory input from and send reciprocal projections to the mPFC. We hypothesize that blockade of prefrontal glucocorticoid receptors can reduce activity of descending glutamatergic input to the VTA, thereby attenuating stress-evoked DA efflux in the mPFC. Using in vivo microdialysis, we demonstrate that acute tail-pinch stress leads to a significant increase in glutamate efflux in the VTA. Blockade of prefrontal glucocorticoid receptors with the selective antagonist CORT 108297 attenuates stress-evoked glutamate efflux in the VTA together with DA efflux in the mPFC. Furthermore, blockade of ionotrophic glutamate receptors in the VTA attenuates stress-evoked DA efflux in the mPFC. We also examine the possible role of glucocorticoid-induced synthesis and release of endocannabinoids acting presynaptically via cannabinoid CB1 receptors to inhibit GABA release onto prefrontal pyramidal cells, thus enhancing descending glutamatergic input to the VTA leading to an increase in mPFC DA efflux during stress. However, administration of the cannabinoid CB1 receptor antagonist into the mPFC does not attenuate stress-evoked DA efflux in the mPFC. Taken together, our data indicate that glucocorticoids act locally within the mPFC to modulate mesocortical DA efflux by potentiation of glutamatergic drive onto DA neurons in the VTA.
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203
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Yuen EY, Zhong P, Li X, Wei J, Yan Z. Restoration of glutamatergic transmission by dopamine D4 receptors in stressed animals. J Biol Chem 2013; 288:26112-26120. [PMID: 23884421 DOI: 10.1074/jbc.m112.396648] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
The prefrontal cortex (PFC), a key brain region for cognitive and emotional processes, is highly regulated by dopaminergic inputs. The dopamine D4 receptor, which is enriched in PFC, has been implicated in mental disorders, such as attention deficit-hyperactivity disorder and schizophrenia. Recently we have found homeostatic regulation of AMPA receptor-mediated synaptic transmission in PFC pyramidal neurons by the D4 receptor, providing a potential mechanism for D4 in stabilizing cortical excitability. Because stress is tightly linked to adaptive and maladaptive changes associated with mental health and disorders, we examined the synaptic actions of D4 in stressed rats. We found that neural excitability was elevated by acute stress and dampened by repeated stress. D4 activation produced a potent reduction of excitatory transmission in acutely stressed animals and a marked increase of excitatory transmission in repeatedly stressed animals. These effects of D4 targeted GluA2-lacking AMPA receptors and relied on the bi-directional regulation of calcium/calmodulin kinase II activity. The restoration of PFC glutamatergic transmission in stress conditions may enable D4 receptors to serve as a synaptic stabilizer in normal and pathological conditions.
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Affiliation(s)
- Eunice Y Yuen
- From the Department of Physiology and Biophysics, State University of New York at Buffalo, School of Medicine and Biomedical Sciences, Buffalo, New York 14214
| | - Ping Zhong
- From the Department of Physiology and Biophysics, State University of New York at Buffalo, School of Medicine and Biomedical Sciences, Buffalo, New York 14214
| | - Xiangning Li
- From the Department of Physiology and Biophysics, State University of New York at Buffalo, School of Medicine and Biomedical Sciences, Buffalo, New York 14214
| | - Jing Wei
- From the Department of Physiology and Biophysics, State University of New York at Buffalo, School of Medicine and Biomedical Sciences, Buffalo, New York 14214
| | - Zhen Yan
- From the Department of Physiology and Biophysics, State University of New York at Buffalo, School of Medicine and Biomedical Sciences, Buffalo, New York 14214.
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204
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Joëls M, Pasricha N, Karst H. The interplay between rapid and slow corticosteroid actions in brain. Eur J Pharmacol 2013; 719:44-52. [PMID: 23886619 DOI: 10.1016/j.ejphar.2013.07.015] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2013] [Revised: 07/01/2013] [Accepted: 07/04/2013] [Indexed: 11/26/2022]
Abstract
Stress causes the release of many transmitters and hormones, including corticosteroids. These molecules enter the brain and exert their effects through the mineralo- and glucocorticoid receptor. The former receptor plays an important role in neuronal stability. However, it also mediates rapid non-genomic corticosteroid effects that in synergy with other stress mediators activate limbic cells and promote behavioral choices allowing the organism to quickly respond to the imminent danger. Glucocorticoid receptors primarily mediate slow genomic effects, for instance in the hippocampus and prefrontal cortex, which are thought to contribute to contextual and higher cognitive aspects of behavioral performance several hours after stress. Rapid and slow effects interact and collectively contribute to successful behavioral adaptation. Long-term disturbances in the release pattern of corticosteroid hormones and in the responsiveness of their receptors give rise to structural and functional changes in neuronal properties which may contribute to the expression of psychopathology.
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Affiliation(s)
- Marian Joëls
- Department of Neuroscience & Pharmacology, Brain Center Rudolf Magnus, University Medical Center Utrecht, Universiteitsweg 100, 3584 CG Utrecht, The Netherlands.
| | - Natasha Pasricha
- Department of Neuroscience & Pharmacology, Brain Center Rudolf Magnus, University Medical Center Utrecht, Universiteitsweg 100, 3584 CG Utrecht, The Netherlands
| | - Henk Karst
- Department of Neuroscience & Pharmacology, Brain Center Rudolf Magnus, University Medical Center Utrecht, Universiteitsweg 100, 3584 CG Utrecht, The Netherlands
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205
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Tokarski K, Bobula B, Grzegorzewska-Hiczwa M, Kusek M, Hess G. Stress- and antidepressant treatment-induced modifications of 5-HT₇ receptor functions in the rat brain. Pharmacol Rep 2013; 64:1305-15. [PMID: 23406741 DOI: 10.1016/s1734-1140(12)70928-3] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2012] [Revised: 10/24/2012] [Indexed: 01/07/2023]
Abstract
This paper summarizes a series of electrophysiological studies aimed at finding the effects of the activation of 5-HT(7) receptors on neuronal excitability as well as on excitatory and inhibitory synaptic transmission in the hippocampus and in the frontal cortex of the rat. These studies demonstrated that 5-HT(7) receptors play an important role in the modulation of the activity of the hippocampal network by regulating the excitability of pyramidal cells of the CA1 area, as well as via their effect on GABA and glutamatergic transmission. The reactivity of 5-HT(7) receptors in the hippocampus is decreased by repeated administration of antidepressant drugs and increased by a prolonged high level of corticosterone. More importantly, administration of antidepressant drug, imipramine, prevents the occurrence of corticosterone-induced changes in the function of hippocampal 5-HT(7) receptors. It has also been found that the blockade of 5-HT(7) receptors by the selective antagonist SB 269970, lasting for a few days, causes similar changes to those observed after long-term administration of antidepressants. Thus, it seems that the pharmacological blockade of 5-HT(7) receptors produces faster effects compared to classic antidepressant drugs. A similarity between the changes in the glutamatergic transmission induced by the blockade of 5 HT7 receptors and those caused by repeated administration of the antidepressant drug, imipramine, has also been found in the frontal cortex. It has also been shown that the changes in glutamatergic transmission and the impairment of long-term synaptic plasticity in the frontal cortex of animals subjected to repeated restraint stress are reversed by the blockade of 5-HT(7) receptors. Overall, these studies, together with the data provided by other investigators, support the hypothesis that 5-HT(7) receptor antagonists may become a prototype of a new class of antidepressant drugs. Such compounds will not function by blocking 5-HT reuptake, as many of the currently used drugs, but through a direct interaction with the 5-HT(7) receptor. This type of action is highly selective and usually does not require the occurrence of adaptive changes in neuronal functions, thus allowing for a much quicker therapeutic effect.
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Affiliation(s)
- Krzysztof Tokarski
- Department of Physiology, Institute of Pharmacology, Polish Academy of Sciences, Smętna 12, PL 31-343 Kraków, Poland.
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206
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Cheng J, Liu W, Duffney LJ, Yan Z. SNARE proteins are essential in the potentiation of NMDA receptors by group II metabotropic glutamate receptors. J Physiol 2013; 591:3935-47. [PMID: 23774277 DOI: 10.1113/jphysiol.2013.255075] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
The group II metabotropic glutamate receptors (group II mGluRs) have emerged as the new drug targets for the treatment of mental disorders like schizophrenia. To understand the potential mechanisms underlying the antipsychotic effects of group II mGluRs, we examined their impact on NMDA receptors (NMDARs), since NMDAR hypofunction has been implicated in schizophrenia. The activation of group II mGluRs caused a significant enhancement of NMDAR currents in cortical pyramidal neurons, which was associated with increased NMDAR surface expression and synaptic localization. We further examined whether these effects of group II mGluRs are through the regulation of NMDAR exocytosis via SNARE proteins, a family of proteins involved in vesicle fusion. We found that the enhancing effect of APDC, a selective agonist of group II mGluRs, on NMDAR currents was abolished when botulinum toxin was delivered into the recorded neurons to disrupt the SNARE complex. Inhibiting the function of two key SNARE proteins, SNAP-25 and syntaxin 4, also eliminated the effect of APDC on NMDAR currents. Moreover, the application of APDC increased the activity of Rab4, a small Rab GTPase mediating fast recycling from early endosomes to the plasma membrane, and enhanced the interaction between syntaxin 4 and Rab4. Knockdown of Rab4 or expression of dominant-negative Rab4 attenuated the effect of APDC on NMDAR currents. Taken together, these results have identified key molecules involved in the group II mGluR-induced potentiation of NMDAR exocytosis and function.
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Affiliation(s)
- Jia Cheng
- Department of Physiology and Biophysics, State University of New York at Buffalo, NY 14214, USA
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207
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Abstract
Exposure to various forms of stress is a common daily occurrence in the lives of most individuals, with both positive and negative effects on brain function. The impact of stress is strongly influenced by the type and duration of the stressor. In its acute form, stress may be a necessary adaptive mechanism for survival and with only transient changes within the brain. However, severe and/or prolonged stress causes overactivation and dysregulation of the hypothalamic pituitary adrenal (HPA) axis thus inflicting detrimental changes in the brain structure and function. Therefore, chronic stress is often considered a negative modulator of the cognitive functions including the learning and memory processes. Exposure to long-lasting stress diminishes health and increases vulnerability to mental disorders. In addition, stress exacerbates functional changes associated with various brain disorders including Alzheimer’s disease and Parkinson’s disease. The primary purpose of this paper is to provide an overview for neuroscientists who are seeking a concise account of the effects of stress on learning and memory and associated signal transduction mechanisms. This review discusses chronic mental stress and its detrimental effects on various aspects of brain functions including learning and memory, synaptic plasticity, and cognition-related signaling enabled via key signal transduction molecules.
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208
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Stress and excitatory synapses: from health to disease. Neuroscience 2013; 248:626-36. [PMID: 23727506 DOI: 10.1016/j.neuroscience.2013.05.043] [Citation(s) in RCA: 84] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2013] [Revised: 05/01/2013] [Accepted: 05/21/2013] [Indexed: 01/20/2023]
Abstract
Individuals are exposed to stressful events in their daily life. The effects of stress on brain function ranges from highly adaptive to increasing the risk to develop psychopathology. For example, stressful experiences are remembered well which can be seen as a highly appropriate behavioral adaptation. On the other hand, stress is an important risk factor, in susceptible individuals, for depression and anxiety. An important question that remains to be addressed is how stress regulates brain function and what determines the threshold between adaptive and maladaptive responses. Excitatory synapses play a crucial role in synaptic transmission, synaptic plasticity and behavioral adaptation. In this review we discuss how brief and prolonged exposure to stress, in adulthood and early life, regulate the function of these synapses, and how these effects may contribute to behavioral adaptation and psychopathology.
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209
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Spinal serum-inducible and glucocorticoid-inducible kinase 1 mediates neuropathic pain via kalirin and downstream PSD-95-dependent NR2B phosphorylation in rats. J Neurosci 2013; 33:5227-40. [PMID: 23516288 DOI: 10.1523/jneurosci.4452-12.2013] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
The coupling of the spinal postsynaptic density-95 (PSD-95) with the glutamatergic N-methyl-d-aspartate receptor NR2B subunit and the subsequent NR2B phosphorylation contribute to pain-related plasticity. Increasing evidence reveals that kalirin, a Rho-guanine nucleotide exchange factor, modulates PSD-95-NR2B-dependent neuroplasticity. Our laboratory recently demonstrated that serum-inducible and glucocorticoid-inducible kinase 1 (SGK1) participates in inflammation-associated pain hypersensitivity by modulating spinal glutamatergic neurotransmission. Because kalirin is one of the proteins in PSD that is highly phosphorylated by various kinases, we tested whether kalirin could be a downstream target of spinal SGK1 that participates in neuropathic pain development via regulation of the PSD-95-NR2B coupling-dependent phosphorylation of NR2B. We observed that spinal nerve ligation (SNL, L5) in male Sprague Dawley rats resulted in behavioral allodynia, which was associated with phosphorylated SGK1 (pSGK1), kalirin, and phosphorylated NR2B (pNR2B) expression and an increase in pSGK1-kalirin-PSD-95-pNR2B coprecipitation in the ipsilateral dorsal horn (L4-L5). SNL-enhanced kalirin immunofluorescence was coincident with pSGK1, PSD-95, and pNR2B immunoreactivity. Small-interfering RNA (siRNA) that targeted spinal kalirin mRNA expression (10 μg, 10 μl; i.t.) reduced SNL-induced allodynia, kalirin and pNR2B expression, as well as kalirin-PSD-95 and PSD-95-pNR2B coupling and costaining without affecting SGK1 phosphorylation. Daily administration of GSK-650394 (an SGK1 antagonist; 100 nm, 10 μl, i.t.) not only exhibited effects similar to the kalirin mRNA-targeting siRNA but also attenuated pSGK1-kalirin costaining and SGK1-kalirin coupling. We suggest that nerve injury could induce spinal SGK1 phosphorylation that subsequently interacts with and upregulates kalirin to participate in neuropathic pain development via PSD-95-NR2B coupling-dependent NR2B phosphorylation.
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210
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Regulating Prefrontal Cortex Activation: An Emerging Role for the 5-HT2A Serotonin Receptor in the Modulation of Emotion-Based Actions? Mol Neurobiol 2013; 48:841-53. [DOI: 10.1007/s12035-013-8472-0] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2013] [Accepted: 05/06/2013] [Indexed: 10/26/2022]
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211
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Role for the kinase SGK1 in stress, depression, and glucocorticoid effects on hippocampal neurogenesis. Proc Natl Acad Sci U S A 2013; 110:8708-13. [PMID: 23650397 DOI: 10.1073/pnas.1300886110] [Citation(s) in RCA: 253] [Impact Index Per Article: 21.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
Stress and glucocorticoid hormones regulate hippocampal neurogenesis, but the molecular mechanisms mediating these effects are poorly understood. Here we identify the glucocorticoid receptor (GR) target gene, serum- and glucocorticoid-inducible kinase 1 (SGK1), as one such mechanism. Using a human hippocampal progenitor cell line, we found that a small molecule inhibitor for SGK1, GSK650394, counteracted the cortisol-induced reduction in neurogenesis. Moreover, gene expression and pathway analysis showed that inhibition of the neurogenic Hedgehog pathway by cortisol was SGK1-dependent. SGK1 also potentiated and maintained GR activation in the presence of cortisol, and even after cortisol withdrawal, by increasing GR phosphorylation and GR nuclear translocation. Experiments combining the inhibitor for SGK1, GSK650394, with the GR antagonist, RU486, demonstrated that SGK1 was involved in the cortisol-induced reduction in progenitor proliferation both downstream of GR, by regulating relevant target genes, and upstream of GR, by increasing GR function. Corroborating the relevance of these findings in clinical and rodent settings, we also observed a significant increase of SGK1 mRNA in peripheral blood of drug-free depressed patients, as well as in the hippocampus of rats subjected to either unpredictable chronic mild stress or prenatal stress. Our findings identify SGK1 as a mediator for the effects of cortisol on neurogenesis and GR function, with particular relevance to stress and depression.
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212
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Effects of time of feeding on psychostimulant reward, conditioned place preference, metabolic hormone levels, and nucleus accumbens biochemical measures in food-restricted rats. Psychopharmacology (Berl) 2013; 227:307-20. [PMID: 23354537 PMCID: PMC3637844 DOI: 10.1007/s00213-013-2981-4] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/12/2012] [Accepted: 12/17/2012] [Indexed: 10/27/2022]
Abstract
RATIONALE Chronic food restriction (FR) increases rewarding effects of abused drugs and persistence of a cocaine-conditioned place preference (CPP). When there is a single daily meal, circadian rhythms are correspondingly entrained, and pre- and postprandial periods are accompanied by different circulating levels of metabolic hormones that modulate brain dopamine function. OBJECTIVES The present study assessed whether rewarding effects of d-amphetamine, cocaine, and persistence of cocaine-CPP differ between FR subjects tested in the pre- and postprandial periods. MATERIALS AND METHODS Rats were stereotaxically implanted with intracerebral microinjection cannulae and an electrode in lateral hypothalamus. Rewarding effects of d-amphetamine and cocaine were assessed using electrical self-stimulation in rats tested 1-4 or 18-21 h after the daily meal. Nonimplanted subjects acquired a cocaine-CPP while ad libitum fed and then were switched to FR and tested for CPP at these same times. RESULTS Rewarding effects of intranucleus accumbens (NAc) d-amphetamine, intraventricular cocaine, and persistence of cocaine-CPP did not differ between rats tested 18-21 h food-deprived, when ghrelin and insulin levels were at peak and nadir, respectively, and those tested 1-4 h after feeding. Rats that expressed a persistent CPP had elevated levels of p-ERK1, GluA1, and p-Ser845-GluA1 in NAc core, and the latter correlated with CPP expression. CONCLUSIONS Psychostimulant reward and persistence of CPP in FR rats are unaffected by time of testing relative to the daily meal. Further, NAc biochemical responses previously associated with enhanced drug responsiveness in FR rats are associated with persistent CPP expression.
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213
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Impairment of synaptic plasticity by the stress mediator CRH involves selective destruction of thin dendritic spines via RhoA signaling. Mol Psychiatry 2013; 18:485-96. [PMID: 22411227 PMCID: PMC3440527 DOI: 10.1038/mp.2012.17] [Citation(s) in RCA: 84] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Stress is ubiquitous in modern life and exerts profound effects on cognitive and emotional functions. Thus, whereas acute stress enhances memory, longer episodes exert negative effects through as yet unresolved mechanisms. We report a novel, hippocampus-intrinsic mechanism for the selective memory defects that are provoked by stress. CRH (corticotropin-releasing hormone), a peptide released from hippocampal neurons during stress, depressed synaptic transmission, blocked activity-induced polymerization of spine actin and impaired synaptic plasticity in adult hippocampal slices. Live, multiphoton imaging demonstrated a selective vulnerability of thin dendritic spines to this stress hormone, resulting in depletion of small, potentiation-ready excitatory synapses. The underlying molecular mechanisms required activation and signaling of the actin-regulating small GTPase, RhoA. These results implicate the selective loss of dendritic spine sub-populations as a novel structural and functional foundation for the clinically important effects of stress on cognitive and emotional processes.
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214
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Abdallah CG, Coplan JD, Jackowski A, Sato JR, Mao X, Shungu DC, Mathew SJ. A pilot study of hippocampal volume and N-acetylaspartate (NAA) as response biomarkers in riluzole-treated patients with GAD. Eur Neuropsychopharmacol 2013; 23:276-84. [PMID: 22739126 PMCID: PMC3473175 DOI: 10.1016/j.euroneuro.2012.05.009] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/09/2012] [Revised: 05/08/2012] [Accepted: 05/29/2012] [Indexed: 12/25/2022]
Abstract
Anxiolytic benefit following chronic treatment with the glutamate modulating agent riluzole in patients with generalized anxiety disorder (GAD) was previously associated with differential changes in hippocampal NAA concentrations. Here, we investigated the association between hippocampal volume and hippocampal NAA in the context of riluzole response in GAD. Eighteen medication-free adult patients with GAD received 8-week of open-label riluzole. Ten healthy subjects served as a comparison group. Participants underwent magnetic resonance imaging and spectroscopy at baseline and at the end of Week 8. GAD patients who completed all interventions were classified as remitters (n=7) or non-remitters (n=6), based on final Hamilton Anxiety Rating Scale (HAM-A) scores ≤7. At baseline, GAD patients had a significant reduction in total hippocampal volume compared to healthy subjects (F(1,21)=6.55, p=0.02). This reduction was most pronounced in the remitters, compared to non-remitters and healthy subjects. Delta (final-baseline) hippocampal volume was positively correlated with delta NAA in GAD. This positive association was highly significant in the right hippocampus in GAD [r=0.81, p=0.002], with no significant association in healthy subjects [Fisher r-to-z p=0.017]. Across all GAD patients, delta hippocampal volume was positively associated with improvement in HAM-A (rspearman=0.62, p=0.03). These preliminary findings support hippocampal NAA and volume as neural biomarkers substantially associated with therapeutic response to a glutamatergic drug.
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Affiliation(s)
- Chadi G Abdallah
- Division of Neuropsychopharmacology, Department of Psychiatry, SUNY Downstate Medical Center, Brooklyn, NY, USA.
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215
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Sim HR, Choi TY, Lee HJ, Kang EY, Yoon S, Han PL, Choi SY, Baik JH. Role of dopamine D2 receptors in plasticity of stress-induced addictive behaviours. Nat Commun 2013; 4:1579. [DOI: 10.1038/ncomms2598] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2012] [Accepted: 02/12/2013] [Indexed: 12/14/2022] Open
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216
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Jett JD, Morilak DA. Too much of a good thing: blocking noradrenergic facilitation in medial prefrontal cortex prevents the detrimental effects of chronic stress on cognition. Neuropsychopharmacology 2013; 38:585-95. [PMID: 23132268 PMCID: PMC3572455 DOI: 10.1038/npp.2012.216] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Cognitive impairments associated with dysfunction of the medial prefrontal cortex (mPFC) are prominent in stress-related psychiatric disorders. We have shown that enhancing noradrenergic tone acutely in the rat mPFC facilitated extra-dimensional (ED) set-shifting on the attentional set-shifting test (AST), whereas chronic unpredictable stress (CUS) impaired ED. In this study, we tested the hypothesis that the acute facilitatory effect of norepinephrine (NE) in mPFC becomes detrimental when activated repeatedly during CUS. Using microdialysis, we showed that the release of NE evoked in mPFC by acute stress was unchanged at the end of CUS treatment. Thus, to then determine if repeated elicitation of this NE activity in mPFC during CUS may have contributed to the ED deficit, we infused a cocktail of α(1)-, β(1)-, and β(2)-adrenergic receptor antagonists into the mPFC prior to each CUS session, then tested animals drug free on the AST. Antagonist treatment prevented the CUS-induced ED deficit, suggesting that NE signaling during CUS compromised mPFC function. We confirmed that this was not attributable to sensitization of adrenergic receptor function following chronic antagonist treatment, by administering an additional microinjection into the mPFC immediately prior to ED testing. Acute antagonist treatment did not reverse the beneficial effects of chronic drug treatment during CUS, nor have any effect on baseline ED performance in chronic vehicle controls. Thus, we conclude that blockade of noradrenergic receptors in mPFC protected against the detrimental cognitive effects of CUS, and that repeated elicitation of noradrenergic facilitatory activity is one mechanism by which chronic stress may promote mPFC cognitive dysfunction.
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Affiliation(s)
- Julianne D Jett
- Department of Pharmacology and Center for Biomedical Neuroscience, University of Texas Health Science Center, San Antonio, TX, USA
| | - David A Morilak
- Department of Pharmacology and Center for Biomedical Neuroscience, University of Texas Health Science Center, San Antonio, TX, USA,Department of Pharmacology, MC 7764, University of Texas Health Science Center at San Antonio, 7703 Floyd Curl Drive, San Antonio, TX 78229-3900, USA, Tel: +1 210 567 4174, Fax: +1 210 567 4300, E-mail:
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217
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Wang H, Meyer K, Korz V. Stress induced hippocampal mineralocorticoid and estrogen receptor β gene expression and long-term potentiation in male adult rats is sensitive to early-life stress experience. Psychoneuroendocrinology 2013; 38:250-62. [PMID: 22776422 DOI: 10.1016/j.psyneuen.2012.06.004] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/15/2011] [Revised: 06/11/2012] [Accepted: 06/12/2012] [Indexed: 01/06/2023]
Abstract
Glucocorticoid hormones and their receptors have been identified to be involved in emotional and cognitive disorders in early stressed subjects during adulthood. However, the impact of other steroid hormones and receptors has been considered less. Especially, functional roles of estrogen and estrogen receptors in male subjects are largely unknown. Therefore, we measured hippocampal concentrations of 17β-estradiol, corticosterone and testosterone, as well as the gene expression of estrogen receptor α and β (ERα, β), androgen receptor (AR), glucocorticoid (GR) and mineralocorticoid (MR) receptors after stress in adulthood in maternally separated (MS+; at postnatal days 14-16 for 6h each day) and control (MS-) male rats. In vivo hippocampal long-term potentiation (LTP) serves as a cellular model of learning and memory formation. Population spike- (PSA) and the fEPSP-LTP within the dentate gyrus (DG) were reinforced by elevated-platform-stress (EP-stress) in MS- but not in MS+ rats. MR- and ERβ-mRNA were upregulated 1h after EP-stress in MS- but not in MS+ rats as compared to non-stressed littermates. Infusion of an MR antagonist before LTP induction blocked early- and late-PSA- and -fEPSP-LTP, whereas blockade of ERβ impaired only the late PSA-LTP. Application of a DNA methyltransferase (DNMT) inhibitor partly restored the LTP-reinforcement in MS+ rats, accompanied by a retrieval of ERβ- but not MR-mRNA upregulation. Basal ERβ gene promoter methylation was similar between groups, whereas MS+ and MS- rats showed different methylation patterns across CpG sites after EP-stress. These findings indicate a key role of ERβ in early-stress mediated emotionality and emotion-induced late-LTP in adult male rats via DNA methylation mechanisms.
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Affiliation(s)
- Han Wang
- Leibniz Institute for Neurobiology, Brenneckestrasse 6, D-39118 Magdeburg, Germany
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218
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Slezak M, Korostynski M, Gieryk A, Golda S, Dzbek J, Piechota M, Wlazlo E, Bilecki W, Przewlocki R. Astrocytes are a neural target of morphine action via glucocorticoid receptor-dependent signaling. Glia 2013; 61:623-35. [PMID: 23339081 DOI: 10.1002/glia.22460] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2012] [Accepted: 12/05/2012] [Indexed: 12/18/2022]
Abstract
Chronic opioid use leads to the structural reorganization of neuronal networks, involving genetic reprogramming in neurons and glial cells. Our previous in vivo studies have revealed that a significant fraction of the morphine-induced alterations to the striatal transcriptome included glucocorticoid (GC) receptor (GR)-dependent genes. Additional analyses suggested glial cells to be the locus of these changes. In the current study, we aimed to differentiate the direct transcriptional effects of morphine and a GR agonist on primary striatal neurons and astrocytes. Whole-genome transcriptional profiling revealed that while morphine had no significant effect on gene expression in both cell types, dexamethasone significantly altered the transcriptional profile in astrocytes but not neurons. We obtained a complete dataset of genes undergoing the regulation, which includes genes related to glucose metabolism (Pdk4), circadian activity (Per1) and cell differentiation (Sox2). There was also an overlap between morphine-induced transcripts in striatum and GR-dependent transcripts in cultured astrocytes. We further analyzed the regulation of expression of one gene belonging to both groups, serum and GC regulated kinase 1 (Sgk1). We identified two transcriptional variants of Sgk1 that displayed selective GR-dependent upregulation in cultured astrocytes but not neurons. Moreover, these variants were the only two that were found to be upregulated in vivo by morphine in a GR-dependent fashion. Our data suggest that the morphine-induced, GR-dependent component of transcriptome alterations in the striatum is confined to astrocytes. Identification of this mechanism opens new directions for research on the role of astrocytes in the central effects of opioids.
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Affiliation(s)
- Michal Slezak
- Department of Molecular Neuropharmacology, Institute of Pharmacology, Polish Academy of Sciences, Krakow, Poland
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219
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Srinivasan S, Shariff M, Bartlett SE. The role of the glucocorticoids in developing resilience to stress and addiction. Front Psychiatry 2013; 4:68. [PMID: 23914175 PMCID: PMC3730062 DOI: 10.3389/fpsyt.2013.00068] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/13/2013] [Accepted: 06/28/2013] [Indexed: 12/12/2022] Open
Abstract
There is emerging evidence that individuals have the capacity to learn to be resilient by developing protective mechanisms that prevent them from the maladaptive effects of stress that can contribute to addiction. The emerging field of the neuroscience of resilience is beginning to uncover the circuits and molecules that protect against stress-related neuropsychiatric diseases, such as addiction. Glucocorticoids (GCs) are important regulators of basal and stress-related homeostasis in all higher organisms and influence a wide array of genes in almost every organ and tissue. GCs, therefore, are ideally situated to either promote or prevent adaptation to stress. In this review, we will focus on the role of GCs in the hypothalamic-pituitary adrenocortical axis and extra-hypothalamic regions in regulating basal and chronic stress responses. GCs interact with a large number of neurotransmitter and neuropeptide systems that are associated with the development of addiction. Additionally, the review will focus on the orexinergic and cholinergic pathways and highlight their role in stress and addiction. GCs play a key role in promoting the development of resilience or susceptibility and represent important pharmacotherapeutic targets that can reduce the impact of a maladapted stress system for the treatment of stress-induced addiction.
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Affiliation(s)
- Subhashini Srinivasan
- Ernest Gallo Clinic and Research Center at the University of California San Francisco , Emeryville, CA , USA
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220
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Peng HY, Chen GD, Hsieh MC, Lai CY, Huang YP, Lin TB. Spinal SGK1/GRASP-1/Rab4 is involved in complete Freund’s adjuvant-induced inflammatory pain via regulating dorsal horn GluR1-containing AMPA receptor trafficking in rats. Pain 2012; 153:2380-2392. [DOI: 10.1016/j.pain.2012.08.004] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2011] [Revised: 07/24/2012] [Accepted: 08/06/2012] [Indexed: 10/27/2022]
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221
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Ferrari LF, Levine E, Levine JD. Independent contributions of alcohol and stress axis hormones to painful peripheral neuropathy. Neuroscience 2012; 228:409-17. [PMID: 23128028 DOI: 10.1016/j.neuroscience.2012.10.052] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2012] [Revised: 10/24/2012] [Accepted: 10/26/2012] [Indexed: 11/19/2022]
Abstract
Painful small-fiber peripheral neuropathy is a debilitating complication of chronic alcohol abuse. Evidence from previous studies suggests that neuroendocrine mechanisms, in combination with other, as yet unidentified actions of alcohol, are required to produce this neuropathic pain syndrome. In addition to neurotoxic effects of alcohol, in the setting of alcohol abuse neuroendocrine stress axes release glucocorticoids and catecholamines. Since receptors for these stress hormones are located on nociceptors, at which they can act to cause neuronal dysfunction, we tested the hypothesis that alcohol and stress hormones act on the nociceptor, independently, to produce neuropathic pain. We used a rat model, which allows the distinction of the effects of alcohol from those produced by neuroendocrine stress axis mediators. We now demonstrate that topical application of alcohol and exposure to unpredictable sound stress, each alone, has no effect on the nociceptive threshold. However, when animals that had previous exposure to alcohol were subsequently exposed to stress, they rapidly developed mechanical hyperalgesia. Conversely, sound stress followed by topical alcohol exposure also produced mechanical hyperalgesia. The contribution of stress hormones was prevented by spinal intrathecal administration of oligodeoxynucleotides antisense to β(2)-adrenergic or glucocorticoid receptor mRNA, which attenuates receptor level in nociceptors, as well as by adrenal medullectomy. These experiments establish an independent role of alcohol and stress hormones on the primary afferent nociceptor in the induction of painful peripheral neuropathy.
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Affiliation(s)
- L F Ferrari
- Departments of Medicine and Oral Surgery, Division of Neuroscience, University of California at San Francisco, 521 Parnassus Avenue, San Francisco, CA 94143-0440, USA
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222
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Abstract
Anxiety disorders are among the most common mental health problems; deficits in extinction have been implicated as a possible risk factor for the development of these disorders. Fear extinction refers to the ability to adapt as situations change by learning to suppress a previously acquired fear. Attention is directed toward the medial prefrontal cortex (mPFC) and the interaction it has with the amygdala as this circuit has crucial roles in both the acquisition and the extinction of fear associations. Here, we review converging evidence from different laboratories pointing to multiple roles that the mPFC has in fear regulation. Research on rodents indicates opposing roles that the different subregions of the mPFC have in exciting and inhibiting fear. In addition, this review aims to survey the findings addressing the mechanisms by which the mPFC regulates fear. Data from our laboratory and others show that changes in plasticity in the mPFC could be one of the mechanisms mediating extinction of fear. Recent findings on rodents and nonhuman primates report that modifying plasticity in the mPFC alters fear and affects extinction, suggesting that targeting plasticity in the mPFC could constitute a therapeutic tool for the treatment of anxiety disorders.
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Affiliation(s)
- Mouna Maroun
- The Sagol Department of Neurobiology, University of Haifa, Haifa, Israel.
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223
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Licznerski P, Duman RS. Remodeling of axo-spinous synapses in the pathophysiology and treatment of depression. Neuroscience 2012; 251:33-50. [PMID: 23036622 DOI: 10.1016/j.neuroscience.2012.09.057] [Citation(s) in RCA: 122] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2012] [Revised: 09/10/2012] [Accepted: 09/22/2012] [Indexed: 01/22/2023]
Abstract
Dendritic spines provide a compartment for assembly and functional organization of synaptic machinery that plays a fundamental role in neuronal communication and neuroplasticity. Studies in humans as well as in animal models have demonstrated abnormal spine architecture in several psychiatric disorders, including depression and other stress-related illnesses. The negative impact of stress on the density and organization of spines is thought to contribute to the behavioral deficits caused by stress exposure. Moreover, there is now evidence that medication-induced recovery involves changes in synaptic plasticity and dendrite morphology, including increased expression of pre- and postsynaptic plasticity-related proteins, as well as the density and function of axo-spinous synapses. Here we review the evidence from brain imaging and postmortem studies demonstrating that depression is accompanied by structural and functional alterations of cortical and limbic brain regions, including the prefrontal cortex, hippocampus and amygdala. In addition, we present more direct evidence from basic research studies that exposure to stress alters spine morphology, function and plasticity and that antidepressants, particularly new rapid acting agents, reverse these effects. Elucidation of the signaling pathways and molecular mechanisms that control spine synapse assembly and plasticity will contribute to a better understanding of the pathophysiology of depression and development of novel, more effective therapeutic agents.
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Affiliation(s)
- P Licznerski
- Division of Molecular Psychiatry, Abraham Ribicoff Research Facilities, Connecticut Mental Health Center, Yale University School of Medicine, New Haven, CT 06508, United States
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224
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Joëls M, Sarabdjitsingh RA, Karst H. Unraveling the time domains of corticosteroid hormone influences on brain activity: rapid, slow, and chronic modes. Pharmacol Rev 2012; 64:901-38. [PMID: 23023031 DOI: 10.1124/pr.112.005892] [Citation(s) in RCA: 310] [Impact Index Per Article: 23.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/21/2025] Open
Abstract
Brain cells are continuously exposed to corticosteroid hormones, although the levels vary (e.g., after stress). Corticosteroids alter neural activity via two receptor types, mineralocorticoid (MR) and glucocorticoid receptors (GR). These receptors regulate gene transcription but also, as we now know, act nongenomically. Via nongenomic pathways, MRs enhance and GRs suppress neural activity. In the hypothalamus, inhibitory GR effects contribute to negative feedback regulation of the stress axis. Nongenomic MR actions are also important extrahypothalamically and help organisms to immediately select an appropriate response strategy. Via genomic mechanisms, corticosteroid actions in the basolateral amygdala and ventral-most part of the cornu ammonis 1 hippocampal area are generally excitatory, providing an extended window for encoding of emotional aspects of a stressful event. GRs in hippocampal and prefrontal pyramidal cells increase surface expression of α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptors and strengthen glutamatergic signaling through pathways partly overlapping with those involved in long-term potentiation. This raises the threshold for subsequent induction of synaptic potentiation and promotes long-term depression. Synapses activated during stress are thus presumably strengthened but protected against excitatory inputs reaching the cells later. This restores higher cognitive control and promotes, for example, consolidation of stress-related contextual information. When an organism experiences stress early in life or repeatedly in adulthood, the ability to induce synaptic potentiation is strongly reduced and the likelihood to induce depression enhanced, even under rest. Treatment with antiglucocorticoids can ameliorate cellular effects after chronic stress and thus provide an interesting lead for treatment of stress-related disorders.
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Affiliation(s)
- Marian Joëls
- Department of Neuroscience and Pharmacology, Rudolf Magnus Institute, University Medical Center Utrecht, Utrecht, The Netherlands.
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225
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Bagot RC, Tse YC, Nguyen HB, Wong AS, Meaney MJ, Wong TP. Maternal care influences hippocampal N-methyl-D-aspartate receptor function and dynamic regulation by corticosterone in adulthood. Biol Psychiatry 2012; 72:491-8. [PMID: 22521150 DOI: 10.1016/j.biopsych.2012.03.016] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/29/2011] [Revised: 03/15/2012] [Accepted: 03/18/2012] [Indexed: 01/30/2023]
Abstract
BACKGROUND Variations in maternal care in the rat associate with robust differences in hippocampal development and synaptic plasticity in the offspring. Maternal care also influences pituitary-adrenal stress responses and corticosterone (CORT) regulation of hippocampal plasticity. N-methyl-D-aspartate receptors (NMDAR) regulate synaptic plasticity, and NMDAR function is modulated by stress and CORT. We hypothesized that altered NMDAR function underlies the interaction of maternal and stress effects on hippocampal synaptic plasticity. METHODS We used electrophysiology and western blot to examine NMDAR synaptic function/expression and NMDAR-dependent long-term potentiation (LTP) in adult offspring of mothers that varied in the frequency of pup licking/grooming (LG) (i.e., High or Low LG). RESULTS Basal NMDAR synaptic function was enhanced in the hippocampal dentate gyrus (DG) of adult Low LG offspring. Synaptic expression of NMDAR but not α-amino-3-hydroxy-methyl-4-isoxazole propionic acid receptors was also increased. Stress level CORT (100 nmol/L) rapidly (< 20 min) and robustly increased NMDAR function in High LG offspring, eliminating the maternal effect. Corticosterone did not affect NMDAR function in Low LG offspring. Bovine serum albumin-conjugated CORT reproduced the CORT effect in High LG offspring, implicating a membrane-bound corticosteroid receptor. NMDAR hyperfunction might impair synaptic plasticity. Partial NMDAR antagonism by low concentration DL-2-Amino-5-phosphonopentanoic acid rescued a basal LTP deficit in Low LG offspring and inhibited LTP in High LG offspring. CONCLUSIONS Low LG offspring exhibit basally elevated NMDAR function coupled with insensitivity to CORT modulation indicative of a chronic alteration of NMDAR function. Elevated NMDAR function in the hippocampus might underlie impaired LTP in Low LG offspring.
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Affiliation(s)
- Rosemary C Bagot
- Neuroscience Division, Douglas Mental Health University Institute, McGill University, Montreal, Quebec, Canada
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226
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Devilbiss DM, Jenison RL, Berridge CW. Stress-induced impairment of a working memory task: role of spiking rate and spiking history predicted discharge. PLoS Comput Biol 2012; 8:e1002681. [PMID: 23028279 PMCID: PMC3441423 DOI: 10.1371/journal.pcbi.1002681] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2012] [Accepted: 07/19/2012] [Indexed: 12/19/2022] Open
Abstract
Stress, pervasive in society, contributes to over half of all work place accidents a year and over time can contribute to a variety of psychiatric disorders including depression, schizophrenia, and post-traumatic stress disorder. Stress impairs higher cognitive processes, dependent on the prefrontal cortex (PFC) and that involve maintenance and integration of information over extended periods, including working memory and attention. Substantial evidence has demonstrated a relationship between patterns of PFC neuron spiking activity (action-potential discharge) and components of delayed-response tasks used to probe PFC-dependent cognitive function in rats and monkeys. During delay periods of these tasks, persistent spiking activity is posited to be essential for the maintenance of information for working memory and attention. However, the degree to which stress-induced impairment in PFC-dependent cognition involves changes in task-related spiking rates or the ability for PFC neurons to retain information over time remains unknown. In the current study, spiking activity was recorded from the medial PFC of rats performing a delayed-response task of working memory during acute noise stress (93 db). Spike history-predicted discharge (SHPD) for PFC neurons was quantified as a measure of the degree to which ongoing neuronal discharge can be predicted by past spiking activity and reflects the degree to which past information is retained by these neurons over time. We found that PFC neuron discharge is predicted by their past spiking patterns for nearly one second. Acute stress impaired SHPD, selectively during delay intervals of the task, and simultaneously impaired task performance. Despite the reduction in delay-related SHPD, stress increased delay-related spiking rates. These findings suggest that neural codes utilizing SHPD within PFC networks likely reflects an additional important neurophysiological mechanism for maintenance of past information over time. Stress-related impairment of this mechanism is posited to contribute to the cognition-impairing actions of stress.
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227
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Dynamic plasticity: the role of glucocorticoids, brain-derived neurotrophic factor and other trophic factors. Neuroscience 2012; 239:214-27. [PMID: 22922121 DOI: 10.1016/j.neuroscience.2012.08.034] [Citation(s) in RCA: 178] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2012] [Revised: 08/15/2012] [Accepted: 08/16/2012] [Indexed: 12/12/2022]
Abstract
Brain-derived neurotrophic factor (BDNF) is a secreted protein that has been linked to numerous aspects of plasticity in the central nervous system (CNS). Stress-induced remodeling of the hippocampus, prefrontal cortex and amygdala is coincident with changes in the levels of BDNF, which has been shown to act as a trophic factor facilitating the survival of existing and newly born neurons. Initially, hippocampal atrophy after chronic stress was associated with reduced BDNF, leading to the hypothesis that stress-related learning deficits resulted from suppressed hippocampal neurogenesis. However, recent evidence suggests that BDNF also plays a rapid and essential role in regulating synaptic plasticity, providing another mechanism through which BDNF can modulate learning and memory after a stressful event. Numerous reports have shown BDNF levels are highly dynamic in response to stress, and not only vary across brain regions but also fluctuate rapidly, both immediately after a stressor and over the course of a chronic stress paradigm. Yet, BDNF alone is not sufficient to effect many of the changes observed after stress. Glucocorticoids and other molecules have been shown to act in conjunction with BDNF to facilitate both the morphological and molecular changes that occur, particularly changes in spine density and gene expression. This review briefly summarizes the evidence supporting BDNF's role as a trophic factor modulating neuronal survival, and will primarily focus on the interactions between BDNF and other systems within the brain to facilitate synaptic plasticity. This growing body of evidence suggests a more nuanced role for BDNF in stress-related learning and memory, where it acts primarily as a facilitator of plasticity and is dependent upon the coactivation of glucocorticoids and other factors as the determinants of the final cellular response.
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228
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The antidepressant agomelatine inhibits stress-mediated changes in amino acid efflux in the rat hippocampus and amygdala. Brain Res 2012; 1466:91-8. [DOI: 10.1016/j.brainres.2012.05.039] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2011] [Revised: 03/28/2012] [Accepted: 05/21/2012] [Indexed: 12/14/2022]
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229
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Krugers HJ, Karst H, Joels M. Interactions between noradrenaline and corticosteroids in the brain: from electrical activity to cognitive performance. Front Cell Neurosci 2012; 6:15. [PMID: 22509154 PMCID: PMC3321636 DOI: 10.3389/fncel.2012.00015] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2012] [Accepted: 03/20/2012] [Indexed: 11/13/2022] Open
Abstract
One of the core reactions in response to a stressful situation is the activation of the hypothalamus-pituitary-adrenal axis which increases the release of glucocorticoid hormones from the adrenal glands. In concert with other neuro-modulators, such as (nor)adrenaline, these hormones enable and promote cognitive adaptation to stressful events. Recent studies have demonstrated that glucocorticoid hormones and noradrenaline, via their receptors, can both rapidly and persistently regulate the function of excitatory synapses which are critical for storage of information. Here we will review how glucocorticoids and noradrenaline alone and in synergy dynamically tune these synapses in the hippocampus and amygdala, and discuss how these hormones interact to promote behavioral adaptation to stressful situations.
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Affiliation(s)
- Harm J Krugers
- Center for Neuroscience, Swammerdam Institute for Life Sciences, University of Amsterdam, Amsterdam, Netherlands
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230
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Chen Y, Andres AL, Frotscher M, Baram TZ. Tuning synaptic transmission in the hippocampus by stress: the CRH system. Front Cell Neurosci 2012; 6:13. [PMID: 22514519 PMCID: PMC3322336 DOI: 10.3389/fncel.2012.00013] [Citation(s) in RCA: 95] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2012] [Accepted: 03/14/2012] [Indexed: 11/13/2022] Open
Abstract
To enhance survival, an organism needs to remember—and learn from—threatening or stressful events. This fact necessitates the presence of mechanisms by which stress can influence synaptic transmission in brain regions, such as hippocampus, that subserve learning and memory. A major focus of this series of monographs is on the role and actions of adrenal-derived hormones, corticosteroids, and of brain-derived neurotransmitters, on synaptic function in the stressed hippocampus. Here we focus on the contribution of hippocampus-intrinsic, stress-activated CRH-CRH receptor signaling to the function and structure of hippocampal synapses. Corticotropin-releasing hormone (CRH) is expressed in interneurons of adult hippocampus, and is released from axon terminals during stress. The peptide exerts time- and dose-dependent effects on learning and memory via modulation of synaptic function and plasticity. Whereas physiological levels of CRH, acting over seconds to minutes, augment memory processes, exposure to presumed severe-stress levels of the peptide results in spine retraction and loss of synapses over more protracted time-frames. Loss of dendritic spines (and hence of synapses) takes place through actin cytoskeleton collapse downstream of CRHR1 receptors that reside within excitatory synapses on spine heads. Chronic exposure to stress levels of CRH may promote dying-back (atrophy) of spine-carrying dendrites. Thus, the acute effects of CRH may contribute to stress-induced adaptive mechanisms, whereas chronic or excessive exposure to the peptide may promote learning problems and premature cognitive decline.
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Affiliation(s)
- Yuncai Chen
- Departments of Pediatrics, Anatomy/Neurobiology, and Neurology, University of California-Irvine, Irvine CA, USA
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231
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Yuen EY, Wei J, Liu W, Zhong P, Li X, Yan Z. Repeated stress causes cognitive impairment by suppressing glutamate receptor expression and function in prefrontal cortex. Neuron 2012; 73:962-77. [PMID: 22405206 PMCID: PMC3302010 DOI: 10.1016/j.neuron.2011.12.033] [Citation(s) in RCA: 438] [Impact Index Per Article: 33.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/12/2011] [Indexed: 01/13/2023]
Abstract
Chronic stress could trigger maladaptive changes associated with stress-related mental disorders; however, the underlying mechanisms remain elusive. In this study, we found that exposing juvenile male rats to repeated stress significantly impaired the temporal order recognition memory, a cognitive process controlled by the prefrontal cortex (PFC). Concomitantly, significantly reduced AMPAR- and NMDAR-mediated synaptic transmission and glutamate receptor expression were found in PFC pyramidal neurons from repeatedly stressed animals. All these effects relied on activation of glucocorticoid receptors and the subsequent enhancement of ubiquitin/proteasome-mediated degradation of GluR1 and NR1 subunits, which was controlled by the E3 ubiquitin ligase Nedd4-1 and Fbx2, respectively. Inhibition of proteasomes or knockdown of Nedd4-1 and Fbx2 in PFC prevented the loss of glutamatergic responses and recognition memory in stressed animals. Our results suggest that repeated stress dampens PFC glutamatergic transmission by facilitating glutamate receptor turnover, which causes the detrimental effect on PFC-dependent cognitive processes.
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MESH Headings
- 2-Amino-5-phosphonovalerate/pharmacology
- 6-Cyano-7-nitroquinoxaline-2,3-dione/pharmacology
- Analysis of Variance
- Animals
- Bicuculline/pharmacology
- Cognition Disorders/etiology
- Cognition Disorders/pathology
- Disease Models, Animal
- Endosomal Sorting Complexes Required for Transport/metabolism
- Excitatory Amino Acid Antagonists/pharmacology
- Excitatory Postsynaptic Potentials/drug effects
- F-Box Proteins/metabolism
- GABA-A Receptor Antagonists
- Immunoprecipitation
- In Vitro Techniques
- Male
- Nedd4 Ubiquitin Protein Ligases
- Neuropsychological Tests
- Prefrontal Cortex/metabolism
- Prefrontal Cortex/pathology
- Prefrontal Cortex/physiopathology
- Pyramidal Cells/drug effects
- Pyramidal Cells/physiopathology
- RNA, Small Interfering/genetics
- RNA, Small Interfering/metabolism
- Rats
- Rats, Sprague-Dawley
- Receptors, Glutamate/genetics
- Receptors, Glutamate/metabolism
- Recognition, Psychology
- Restraint, Physical/adverse effects
- Stress, Psychological/complications
- Stress, Psychological/pathology
- Ubiquitin-Protein Ligases/metabolism
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Affiliation(s)
| | | | - Wenhua Liu
- Department of Physiology and Biophysics, State University of New York at Buffalo, School of Medicine and Biomedical Sciences, Buffalo, NY 14214
| | - Ping Zhong
- Department of Physiology and Biophysics, State University of New York at Buffalo, School of Medicine and Biomedical Sciences, Buffalo, NY 14214
| | - Xiangning Li
- Department of Physiology and Biophysics, State University of New York at Buffalo, School of Medicine and Biomedical Sciences, Buffalo, NY 14214
| | - Zhen Yan
- Department of Physiology and Biophysics, State University of New York at Buffalo, School of Medicine and Biomedical Sciences, Buffalo, NY 14214
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232
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Tse YC, Bagot RC, Wong TP. Dynamic regulation of NMDAR function in the adult brain by the stress hormone corticosterone. Front Cell Neurosci 2012; 6:9. [PMID: 22408607 PMCID: PMC3294281 DOI: 10.3389/fncel.2012.00009] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2011] [Accepted: 02/17/2012] [Indexed: 12/18/2022] Open
Abstract
Stress and corticosteroids dynamically modulate the expression of synaptic plasticity at glutamatergic synapses in the developed brain. Together with alpha-amino-3-hydroxy-methyl-4-isoxazole propionic acid receptors (AMPAR), N-methyl-D-aspartate receptors (NMDAR) are critical mediators of synaptic function and are essential for the induction of many forms of synaptic plasticity. Regulation of NMDAR function by cortisol/corticosterone (CORT) may be fundamental to the effects of stress on synaptic plasticity. Recent reports of the efficacy of NMDAR antagonists in treating certain stress-associated psychopathologies further highlight the importance of understanding the regulation of NMDAR function by CORT. Knowledge of how corticosteroids regulate NMDAR function within the adult brain is relatively sparse, perhaps due to a common belief that NMDAR function is stable in the adult brain. We review recent results from our laboratory and others demonstrating dynamic regulation of NMDAR function by CORT in the adult brain. In addition, we consider the issue of how differences in the early life environment may program differential sensitivity to modulation of NMDAR function by CORT and how this may influence synaptic function during stress. Findings from these studies demonstrate that NMDAR function in the adult hippocampus remains sensitive to even brief exposures to CORT and that the capacity for modulation of NMDAR may be programmed, in part, by the early life environment. Modulation of NMDAR function may contribute to dynamic regulation of synaptic plasticity and adaptation in the face of stress, however, enhanced NMDAR function may be implicated in mechanisms of stress-related psychopathologies including depression.
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Affiliation(s)
- Yiu Chung Tse
- Neuroscience Division, Douglas Mental Health University Institute, McGill University, Montreal QC, Canada
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233
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Graybeal C, Kiselycznyk C, Holmes A. Stress-induced impairments in prefrontal-mediated behaviors and the role of the N-methyl-D-aspartate receptor. Neuroscience 2012; 211:28-38. [PMID: 22414923 DOI: 10.1016/j.neuroscience.2012.02.042] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2011] [Revised: 02/20/2012] [Accepted: 02/22/2012] [Indexed: 12/31/2022]
Abstract
The prefrontal cortex (PFC) mediates higher-order cognitive and executive functions that subserve various complex, adaptable behaviors, such as cognitive flexibility, attention, and working memory. Deficits in these functions typify multiple neuropsychiatric disorders that are caused or exacerbated by exposure to psychological stress. Here we review recent evidence examining the effects of stress on executive and cognitive functions in rodents and discuss an emerging body of evidence that implicates the N-methyl-D-aspartate receptor (NMDAR) as a potentially critical molecular mechanism mediating these effects. Future work in this area could open up new avenues for developing pharmacotherapies for ameliorating cognitive dysfunction in neuropsychiatric disease.
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Affiliation(s)
- C Graybeal
- Laboratory of Behavioral and Genomic Neuroscience, National Institute on Alcohol Abuse and Alcoholism, NIH, Bethesda, MD 20892-9304, USA.
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234
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Yuen EY, Wei J, Zhong P, Yan Z. Disrupted GABAAR trafficking and synaptic inhibition in a mouse model of Huntington's disease. Neurobiol Dis 2012; 46:497-502. [PMID: 22402331 DOI: 10.1016/j.nbd.2012.02.015] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2011] [Revised: 01/24/2012] [Accepted: 02/20/2012] [Indexed: 01/20/2023] Open
Abstract
Growing evidence suggests that Huntington's disease (HD), a neurodegenerative movement disorder caused by the mutant huntingtin (htt) with an expanded polyglutamine (polyQ) repeat, is associated with the altered intracellular trafficking and synaptic function. GABA(A) receptors, the key determinant of the strength of synaptic inhibition, have been found to bind to the huntingtin associated protein 1 (HAP1). HAP1 serves as an adaptor linking GABA(A) receptors to the kinesin family motor protein 5 (KIF5), controlling the transport of GABA(A) receptors along microtubules in dendrites. In this study, we found that GABA(A)R-mediated synaptic transmission is significantly impaired in a transgenic mouse model of HD expressing polyQ-htt, which is accompanied by the diminished surface expression of GABA(A) receptors. Moreover, the GABA(A)R/HAP1/KIF5 complex is disrupted and dissociated from microtubules in the HD mouse model. These results suggest that GABA(A)R trafficking and function is impaired in HD, presumably due to the interference of KIF5-mediated microtubule-based transport of GABA(A) receptors. The diminished inhibitory synaptic efficacy could contribute to the loss of the excitatory/inhibitory balance, leading to increased neuronal excitotoxicity in HD.
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Affiliation(s)
- Eunice Y Yuen
- Department of Physiology and Biophysics, State University of New York at Buffalo, School of Medicine and Biomedical Sciences, Buffalo, NY 14214, USA
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235
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Erasing synapses in sleep: is it time to be SHY? Neural Plast 2012; 2012:264378. [PMID: 22530156 PMCID: PMC3317003 DOI: 10.1155/2012/264378] [Citation(s) in RCA: 76] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2011] [Accepted: 12/04/2011] [Indexed: 02/04/2023] Open
Abstract
Converging lines of evidence strongly support a role for sleep in brain plasticity. An elegant idea that may explain how sleep accomplishes this role is the "synaptic homeostasis hypothesis (SHY)." According to SHY, sleep promotes net synaptic weakening which offsets net synaptic strengthening that occurs during wakefulness. SHY is intuitively appealing because it relates the homeostatic regulation of sleep to an important function (synaptic plasticity). SHY has also received important experimental support from recent studies in Drosophila melanogaster. There remain, however, a number of unanswered questions about SHY. What is the cellular mechanism governing SHY? How does it fit with what we know about plasticity mechanisms in the brain? In this review, I discuss the evidence and theory of SHY in the context of what is known about Hebbian and non-Hebbian synaptic plasticity. I conclude that while SHY remains an elegant idea, the underlying mechanisms are mysterious and its functional significance unknown.
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236
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Lee JB, Wei J, Liu W, Cheng J, Feng J, Yan Z. Histone deacetylase 6 gates the synaptic action of acute stress in prefrontal cortex. J Physiol 2012; 590:1535-46. [PMID: 22331421 DOI: 10.1113/jphysiol.2011.224907] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
The prefrontal cortex (PFC), a region responsible for high-order cognitive functions, such as decision-making, attention and working memory, is highly influenced by stress and corticosteroid stress hormones. Recently it has been shown that acute stress affects PFC functions by potentiating glutamatergic transmission via a mechanism dependent on glucocorticoid receptor (GR) and its downstream target, serum and glucocorticoid-inducible kinase (SGK). To identify the key regulators of stress responses, we examined the role of histone deacetylase 6 (HDAC6), a unique member of the HDAC family that could regulate the GR chaperone protein heat shock protein 90 (HSP90), in the synaptic action of acute stress in PFC. We found that HDAC6 inhibition or knockdown blocked the enhancement of glutamatergic transmission and glutamate receptor trafficking by acute stress in vivo or corticosterone treatment in vitro. In addition, HDAC6 inhibition blocked the up-regulation of SGK in animals exposed to acute stress. HSP90 inhibition or knockdown produced a similar blockade of the acute stress-induced enhancement of glutamatergic signalling. These findings have identified HDAC6 as a key molecule gating the effects of acute stress on synaptic functions in the PFC.
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Affiliation(s)
- Janine B Lee
- Department of Physiology and Biophysics, State University of New York at Buffalo, Buffalo, NY 14214, USA
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237
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Jiang H, Ren Y, Yuen EY, Zhong P, Ghaedi M, Hu Z, Azabdaftari G, Nakaso K, Yan Z, Feng J. Parkin controls dopamine utilization in human midbrain dopaminergic neurons derived from induced pluripotent stem cells. Nat Commun 2012; 3:668. [PMID: 22314364 DOI: 10.1038/ncomms1669] [Citation(s) in RCA: 201] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2011] [Accepted: 01/09/2012] [Indexed: 12/11/2022] Open
Abstract
Parkinson's disease (PD) is defined by the degeneration of nigral dopaminergic (DA) neurons and can be caused by monogenic mutations of genes such as parkin. The lack of phenotype in parkin knockout mice suggests that human nigral DA neurons have unique vulnerabilities. Here we generate induced pluripotent stem cells from normal subjects and PD patients with parkin mutations. We demonstrate that loss of parkin in human midbrain DA neurons greatly increases the transcription of monoamine oxidases and oxidative stress, significantly reduces DA uptake and increases spontaneous DA release. Lentiviral expression of parkin, but not its PD-linked mutant, rescues these phenotypes. The results suggest that parkin controls dopamine utilization in human midbrain DA neurons by enhancing the precision of DA neurotransmission and suppressing dopamine oxidation. Thus, the study provides novel targets and a physiologically relevant screening platform for disease-modifying therapies of PD.
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Affiliation(s)
- Houbo Jiang
- Department of Physiology and Biophysics, State University of New York at Buffalo, Buffalo, New York 14214, USA
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238
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Mora F, Segovia G, Del Arco A, de Blas M, Garrido P. Stress, neurotransmitters, corticosterone and body-brain integration. Brain Res 2012; 1476:71-85. [PMID: 22285436 DOI: 10.1016/j.brainres.2011.12.049] [Citation(s) in RCA: 151] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2011] [Revised: 12/22/2011] [Accepted: 12/23/2011] [Indexed: 12/26/2022]
Abstract
Stress can be defined as a brain-body reaction towards stimuli arising from the environment or from internal cues that are interpreted as a disruption of homeostasis. The organization of the response to a stressful situation involves not only the activity of different types of neurotransmitter systems in several areas of the limbic system, but also the response of neurons in these areas to several other chemicals and hormones, chiefly glucocorticoids, released from peripheral organs and glands. Thus, stress is probably the process through which body-brain integration plays a major role. Here we review first the responses to an acute stress in terms of neurotransmitters such as dopamine, acetylcholine, glutamate and GABA in areas of the brain involved in the regulation of stress responses. These areas include the prefrontal cortex, amygdala, hippocampus and nucleus accumbens and the interaction among those areas. Then, we consider the role of glucocorticoids and review some recent data about the interaction of these steroids with several neurotransmitters in those same areas of the brain. Also the actions of other substances (neuromodulators) released from peripheral organs such as the pancreas, liver or gonads (insulin, IGF-1, estrogens) are reviewed. The role of an environmental enrichment on these same responses is also discussed. Finally a section is devoted to put into perspective all these environmental-brain-body-brain interactions during stress and their consequences on aging. It is concluded that the integrative perspective framed in this review is relevant for better understanding of how the organism responds to stressful challenges and how this can be modified through different environmental conditions during the process of aging. This article is part of a Special Issue entitled: Brain Integration.
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Affiliation(s)
- Francisco Mora
- Department of Physiology, Faculty of Medicine, Universidad Complutense, Madrid, Spain.
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239
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The stressed synapse: the impact of stress and glucocorticoids on glutamate transmission. Nat Rev Neurosci 2011; 13:22-37. [PMID: 22127301 DOI: 10.1038/nrn3138] [Citation(s) in RCA: 993] [Impact Index Per Article: 70.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Mounting evidence suggests that acute and chronic stress, especially the stress-induced release of glucocorticoids, induces changes in glutamate neurotransmission in the prefrontal cortex and the hippocampus, thereby influencing some aspects of cognitive processing. In addition, dysfunction of glutamatergic neurotransmission is increasingly considered to be a core feature of stress-related mental illnesses. Recent studies have shed light on the mechanisms by which stress and glucocorticoids affect glutamate transmission, including effects on glutamate release, glutamate receptors and glutamate clearance and metabolism. This new understanding provides insights into normal brain functioning, as well as the pathophysiology and potential new treatments of stress-related neuropsychiatric disorders.
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240
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Tse YC, Bagot RC, Hutter JA, Wong AS, Wong TP. Modulation of synaptic plasticity by stress hormone associates with plastic alteration of synaptic NMDA receptor in the adult hippocampus. PLoS One 2011; 6:e27215. [PMID: 22069501 PMCID: PMC3206081 DOI: 10.1371/journal.pone.0027215] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2011] [Accepted: 10/12/2011] [Indexed: 01/22/2023] Open
Abstract
Stress exerts a profound impact on learning and memory, in part, through the actions of adrenal corticosterone (CORT) on synaptic plasticity, a cellular model of learning and memory. Increasing findings suggest that CORT exerts its impact on synaptic plasticity by altering the functional properties of glutamate receptors, which include changes in the motility and function of α-amino-3-hydroxy-5-methylisoxazole-4-propionic acid subtype of glutamate receptor (AMPAR) that are responsible for the expression of synaptic plasticity. Here we provide evidence that CORT could also regulate synaptic plasticity by modulating the function of synaptic N-methyl-D-aspartate receptors (NMDARs), which mediate the induction of synaptic plasticity. We found that stress level CORT applied to adult rat hippocampal slices potentiated evoked NMDAR-mediated synaptic responses within 30 min. Surprisingly, following this fast-onset change, we observed a slow-onset (>1 hour after termination of CORT exposure) increase in synaptic expression of GluN2A-containing NMDARs. To investigate the consequences of the distinct fast- and slow-onset modulation of NMDARs for synaptic plasticity, we examined the formation of long-term potentiation (LTP) and long-term depression (LTD) within relevant time windows. Paralleling the increased NMDAR function, both LTP and LTD were facilitated during CORT treatment. However, 1–2 hours after CORT treatment when synaptic expression of GluN2A-containing NMDARs is increased, bidirectional plasticity was no longer facilitated. Our findings reveal the remarkable plasticity of NMDARs in the adult hippocampus in response to CORT. CORT-mediated slow-onset increase in GluN2A in hippocampal synapses could be a homeostatic mechanism to normalize synaptic plasticity following fast-onset stress-induced facilitation.
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Affiliation(s)
- Yiu Chung Tse
- Neuroscience Division, Douglas Mental Health University Institute, McGill University, Montreal, Quebec, Canada
| | - Rosemary C. Bagot
- Neuroscience Division, Douglas Mental Health University Institute, McGill University, Montreal, Quebec, Canada
| | - Juliana A. Hutter
- Neuroscience Division, Douglas Mental Health University Institute, McGill University, Montreal, Quebec, Canada
| | - Alice S. Wong
- Neuroscience Division, Douglas Mental Health University Institute, McGill University, Montreal, Quebec, Canada
| | - Tak Pan Wong
- Neuroscience Division, Douglas Mental Health University Institute, McGill University, Montreal, Quebec, Canada
- Department of Psychiatry, McGill University, Montreal, Quebec, Canada
- Department of Pharmacology and Therapeutics, McGill University, Montreal, Quebec, Canada
- * E-mail:
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241
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Krugers HJ, Zhou M, Joëls M, Kindt M. Regulation of excitatory synapses and fearful memories by stress hormones. Front Behav Neurosci 2011; 5:62. [PMID: 22013419 PMCID: PMC3190121 DOI: 10.3389/fnbeh.2011.00062] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2011] [Accepted: 09/05/2011] [Indexed: 12/18/2022] Open
Abstract
Memories for emotionally arousing and fearful events are generally well retained. From the evolutionary point of view this is a highly adaptive behavioral response aimed to remember relevant information. However, fearful memories can also be inappropriately and vividly (re)expressed, such as in posttraumatic stress disorder. The memory formation of emotionally arousing events is largely modulated by hormones, peptides, and neurotransmitters which are released during and after exposure to these conditions. One of the core reactions in response to a stressful situation is the rapid activation of the autonomic nervous system, which results in the release of norepinephrine in the brain. In addition, stressful events stimulate the hypothalamus-pituitary-adrenal axis which slowly increases the release of glucocorticoid hormones from the adrenal glands. Here we will review how glucocorticoids and norepinephrine regulate the formation of fearful memories in rodents and humans and how these hormones can facilitate the storage of information by regulating excitatory synapses.
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Affiliation(s)
- Harm J. Krugers
- Center for Neuroscience, Swammerdam Institute for Life Sciences, University of AmsterdamAmsterdam, Netherlands
| | - Ming Zhou
- Center for Neuroscience, Swammerdam Institute for Life Sciences, University of AmsterdamAmsterdam, Netherlands
| | - Marian Joëls
- Center for Neuroscience, Swammerdam Institute for Life Sciences, University of AmsterdamAmsterdam, Netherlands
- Department of Neuroscience and Pharmacology, Rudolf Magnus Institute of Neuroscience, University Medical Center UtrechtUtrecht, Netherlands
| | - Merel Kindt
- Department of Clinical Psychology, University of AmsterdamAmsterdam, Netherlands
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242
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Calabrese F, Molteni R, Riva MA. Antistress properties of antidepressant drugs and their clinical implications. Pharmacol Ther 2011; 132:39-56. [DOI: 10.1016/j.pharmthera.2011.05.007] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2011] [Accepted: 05/09/2011] [Indexed: 02/07/2023]
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243
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Marsden W. Stressor-induced NMDAR dysfunction as a unifying hypothesis for the aetiology, pathogenesis and comorbidity of clinical depression. Med Hypotheses 2011; 77:508-28. [DOI: 10.1016/j.mehy.2011.06.021] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2011] [Accepted: 06/05/2011] [Indexed: 02/07/2023]
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244
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Glucocorticoids are critical regulators of dendritic spine development and plasticity in vivo. Proc Natl Acad Sci U S A 2011; 108:16074-9. [PMID: 21911374 DOI: 10.1073/pnas.1110444108] [Citation(s) in RCA: 274] [Impact Index Per Article: 19.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Glucocorticoids are a family of hormones that coordinate diverse physiological processes in responding to stress. Prolonged glucocorticoid exposure over weeks has been linked to dendritic atrophy and spine loss in fixed tissue studies of adult brains, but it is unclear how glucocorticoids may affect the dynamic processes of dendritic spine formation and elimination in vivo. Furthermore, relatively few studies have examined the effects of stress and glucocorticoids on spines during the postnatal and adolescent period, which is characterized by rapid synaptogenesis followed by protracted synaptic pruning. To determine whether and to what extent glucocorticoids regulate dendritic spine development and plasticity, we used transcranial two-photon microscopy to track the formation and elimination of dendritic spines in vivo after treatment with glucocorticoids in developing and adult mice. Corticosterone, the principal murine glucocorticoid, had potent dose-dependent effects on dendritic spine dynamics, increasing spine turnover within several hours in the developing barrel cortex. The adult barrel cortex exhibited diminished baseline spine turnover rates, but these rates were also enhanced by corticosterone. Similar changes occurred in multiple cortical areas, suggesting a generalized effect. However, reducing endogenous glucocorticoid activity by dexamethasone suppression or corticosteroid receptor antagonists caused a substantial reduction in spine turnover rates, and the former was reversed by corticosterone replacement. Notably, we found that chronic glucocorticoid excess led to an abnormal loss of stable spines that were established early in life. Together, these findings establish a critical role for glucocorticoids in the development and maintenance of dendritic spines in the living cortex.
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245
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Niciu MJ, Kelmendi B, Sanacora G. Overview of glutamatergic neurotransmission in the nervous system. Pharmacol Biochem Behav 2011; 100:656-64. [PMID: 21889952 DOI: 10.1016/j.pbb.2011.08.008] [Citation(s) in RCA: 218] [Impact Index Per Article: 15.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/12/2011] [Accepted: 08/10/2011] [Indexed: 02/07/2023]
Abstract
This introductory article to the special edition on glutamate neurotransmission in neuropsychiatric disorders provides an overview of glutamate neurotransmitter system physiology and pharmacology. Glutamate was only relatively recently recognized as the major excitatory neurotransmitter in the mammalian brain, in part due to its ubiquitous nature and diverse metabolic roles within the CNS. The extremely high concentration of glutamate in brain tissue paired with its excitotoxic potential requires tight physiological regulation of extracellular glutamate levels and receptor signaling in order to assure optimal excitatory neurotransmission but limits excitotoxic damage. In order to achieve this high level of control, the system has developed a complex physiology with multiple regulatory processes modulating glutamate metabolism, release, receptor signaling, and uptake. The basic physiology of the various regulatory components of the system including the rich receptor pharmacology is briefly reviewed. Potential contributions from each of the system's components to the pathophysiology of neuropsychiatric illnesses are briefly discussed, as are the many new pharmacological targets for drug development provided by the system, especially as they pertain to the proceeding preclinical and clinical articles in this issue.
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Affiliation(s)
- Mark J Niciu
- Department of Psychiatry, Yale University School of Medicine, New Haven, CT 06519, USA
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246
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Cognitive response to estradiol in postmenopausal women is modified by high cortisol. Neurobiol Aging 2011; 33:829.e9-20. [PMID: 21855173 DOI: 10.1016/j.neurobiolaging.2011.07.002] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2011] [Revised: 05/28/2011] [Accepted: 07/07/2011] [Indexed: 01/11/2023]
Abstract
Estradiol has potent favorable effects on brain function and behavior in animals while in human trials, the results are inconsistent. A number of potential mediating variables influencing response to estradiol have been proposed to account for this variability, 1 of which includes stress. We conducted a placebo-controlled study to examine joint and independent effects of estradiol and elevated levels of the stress hormone cortisol on cognition and biomarkers of aging and neurodegenerative disease. Thirty-nine healthy postmenopausal women (56-84 years) received 0.10 mg/dL of transdermal 17β-estradiol (E2) or placebo for 8 weeks. During the last 4 days of the trial, subjects also received 90 mg/day (30 mg 3×/day) of oral hydrocortisone (CORT) to induce stress-level elevations in cortisol, or a matched placebo. The 4 groups thus included placebo (placebo patch/placebo pill), CORT-alone (placebo patch/hydrocortisone), E2-alone (estradiol patch/placebo pill), and E2+CORT (estradiol patch/hydrocortisone). Eight weeks of E2 increased plasma estradiol by 167%, and 4 days of CORT increased plasma cortisol by 119%. Overall, E2 had favorable effects on verbal memory (p = 0.03), working memory (p = 0.02), and selective attention (p = 0.04), and the magnitude of these effects was attenuated for E2+CORT. E2-alone and E2+CORT had opposing effects on plasma levels of the amyloid-β (Aβ) biomarker (Aβ40/42 ratio, p < 0.05), with the more favorable response observed for E2-alone. CORT-induced increases in insulin-like growth factor-1 were blunted by E2 coadministration. Our findings indicate that cognitive and physiological responses to estradiol are adversely affected by elevated stress hormone levels of cortisol in healthy postmenopausal women.
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247
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Towards a glutamate hypothesis of depression: an emerging frontier of neuropsychopharmacology for mood disorders. Neuropharmacology 2011; 62:63-77. [PMID: 21827775 DOI: 10.1016/j.neuropharm.2011.07.036] [Citation(s) in RCA: 784] [Impact Index Per Article: 56.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2011] [Revised: 07/22/2011] [Accepted: 07/23/2011] [Indexed: 12/12/2022]
Abstract
Half a century after the first formulation of the monoamine hypothesis, compelling evidence implies that long-term changes in an array of brain areas and circuits mediating complex cognitive-emotional behaviors represent the biological underpinnings of mood/anxiety disorders. A large number of clinical studies suggest that pathophysiology is associated with dysfunction of the predominant glutamatergic system, malfunction in the mechanisms regulating clearance and metabolism of glutamate, and cytoarchitectural/morphological maladaptive changes in a number of brain areas mediating cognitive-emotional behaviors. Concurrently, a wealth of data from animal models have shown that different types of environmental stress enhance glutamate release/transmission in limbic/cortical areas and exert powerful structural effects, inducing dendritic remodeling, reduction of synapses and possibly volumetric reductions resembling those observed in depressed patients. Because a vast majority of neurons and synapses in these areas and circuits use glutamate as neurotransmitter, it would be limiting to maintain that glutamate is in some way 'involved' in mood/anxiety disorders; rather it should be recognized that the glutamatergic system is a primary mediator of psychiatric pathology and, potentially, also a final common pathway for the therapeutic action of antidepressant agents. A paradigm shift from a monoamine hypothesis of depression to a neuroplasticity hypothesis focused on glutamate may represent a substantial advancement in the working hypothesis that drives research for new drugs and therapies. Importantly, despite the availability of multiple classes of drugs with monoamine-based mechanisms of action, there remains a large percentage of patients who fail to achieve a sustained remission of depressive symptoms. The unmet need for improved pharmacotherapies for treatment-resistant depression means there is a large space for the development of new compounds with novel mechanisms of action such as glutamate transmission and related pathways. This article is part of a Special Issue entitled 'Anxiety and Depression'.
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248
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Rasmussen S, Miller MM, Filipski SB, Tolwani RJ. Cage change influences serum corticosterone and anxiety-like behaviors in the mouse. JOURNAL OF THE AMERICAN ASSOCIATION FOR LABORATORY ANIMAL SCIENCE : JAALAS 2011; 50:479-83. [PMID: 21838975 PMCID: PMC3148651] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Received: 08/21/2010] [Revised: 10/18/2010] [Accepted: 02/01/2011] [Indexed: 05/31/2023]
Abstract
Environmental variables and husbandry practices can influence physiology and alter behavior in mice. Our study evaluated the effects of cage change on serum corticosterone levels and anxiety-like behaviors in C57BL/6 male mice. We examined the effects of 3 different methods of performing cage transfer and of transferring mice to a clean or a dirty familiar cage microenvironment. The 3 different handling methods were forceps transfer, gentle transfer with gloved hands, and a passive transfer technique that did not involve active handling. Active handling methods and transfer to both clean and dirty cage microenvironments significantly increased serum corticosterone 15 min after cage change; however, at 60 min after cage change, levels were comparable to those of unmanipulated mice. Although the effects were transient, cage change altered anxiety-like behaviors in the open field when behavioral testing was performed on the same day. These results demonstrate that the timing of cage change can influence behavioral results, an effect that is an important consideration for rodent behavioral studies.
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Affiliation(s)
- Skye Rasmussen
- The Comparative Bioscience Center, Memorial Sloan-Kettering Cancer Center, The Rockefeller University, New York, New York, USA.
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249
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Henckens MJAG, van Wingen GA, Joëls M, Fernández G. Time-dependent corticosteroid modulation of prefrontal working memory processing. Proc Natl Acad Sci U S A 2011; 108:5801-6. [PMID: 21436038 PMCID: PMC3078384 DOI: 10.1073/pnas.1019128108] [Citation(s) in RCA: 126] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Corticosteroids are potent modulators of human higher cognitive function. They are released in response to stress, and are thought to be involved in the modulation of cognitive function by inducing distinct rapid nongenomic, and slow genomic changes, affecting neural plasticity throughout the brain. However, their exact effects on the neural correlates of higher-order cognitive function as performed by the prefrontal cortex at the human brain system level remain to be elucidated. Here, we targeted these time-dependent effects of corticosteroids on prefrontal cortex processing in humans using a working memory (WM) paradigm during functional MRI scanning. Implementing a randomized, double-blind, placebo-controlled design, 72 young, healthy men received 10 mg hydrocortisone either 30 min (rapid corticosteroid effects) or 240 min (slow corticosteroid effects), or placebo before a numerical n-back task with differential load (0- to 3-back). Corticosteroids' slow effects appeared to improve working memory performance and increased neuronal activity during WM performance in the dorsolateral prefrontal cortex depending on WM load, whereas no effects of corticosteroids' rapid actions were observed. Thereby, the slow actions of corticosteroids seem to facilitate adequate higher-order cognitive functioning, which may support recovery in the aftermath of stress exposure.
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Affiliation(s)
- Marloes J A G Henckens
- Department of Cognitive Neurology and Memory, Centre for Cognitive Neuroimaging, Donders Institute for Brain, Cognition and Behaviour, Radboud University Nijmegen, 6500 HB, Nijmegen, The Netherlands.
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250
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Garrido P. Aging and stress: past hypotheses, present approaches and perspectives. Aging Dis 2011; 2:80-99. [PMID: 22396868 PMCID: PMC3295041] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2010] [Revised: 08/05/2010] [Accepted: 08/05/2010] [Indexed: 05/31/2023] Open
Abstract
Brain aging has been suggested to be conditioned by an excessive glucocortioid secretion leading to damages on brain areas involved not only in cognitive and emotional processes but also in the control of the activity of the hypothalamic-pituitary adrenal axis. This review describes some of the hypothesis that try to explain the relation between the dysregulation of the stress response and brain aging, focusing on corticosterone but also on neurotransmission in the hippocampus, the prefrontal cortex and the amygdala. Moreover, different molecular factors can account for an enhanced vulnerability of the aged brain to stress exposure, specially for resilience. Among them, good candidates could be those mechanisms determining the levels of corticosterone in the brain, several molecules downstream glucocorticoid receptor activation (ie: heat shock proteins, BAG-1) or even the epigenetic programming of the HPA axis in early stages. In conclusion, genetic and environmental factors (early life stress, chronic stress during adulthood) can produce an enhanced vulnerability and a reduced resilience of the brain to subsequent stress exposures or to metabolic challenges leading, in turn, to an unsuccessful aging of the brain. However, results obtained with the use of the environmental enrichment model in animals, added to several results in humans also described in this review suggest that positive environmental factors (cognitive-demanding tasks or physical exercise) can help to maintain neuronal plasticity during aging and to protect the brain against the damaging effects of stress exposure.
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Affiliation(s)
- Pedro Garrido
- Correspondence should be addressed to: Dr. Pedro Garrido, Department of Physiology, Faculty of Medicine, Universidad Complutense, Avda Complutense s/n, 28040, SPAIN. E-mail:
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