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Pati E, Franceschi Biagioni A, Casani R, Lozano N, Kostarelos K, Cellot G, Ballerini L. Delivery of graphene oxide nanosheets modulates glutamate release and normalizes amygdala synaptic plasticity to improve anxiety-related behavior. NANOSCALE 2023; 15:18581-18591. [PMID: 37955642 DOI: 10.1039/d3nr04490d] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/14/2023]
Abstract
Graphene oxide nanosheets (GO) were reported to alter neurobiological processes involving cell membrane dynamics. GO ability to reversibly downregulate specifically glutamatergic synapses underpins their potential in future neurotherapeutic developments. Aberrant glutamate plasticity contributes to stress-related psychopathology and drugs which target dysregulated glutamate represent promising treatments. We find that in a rat model of post-traumatic stress disorder (PTSD), a single injection of GO to the lateral amygdala following the stressful event induced PTSD-related behavior remission and reduced dendritic spine densities. We explored from a mechanistic perspective how GO could impair glutamate synaptic plasticity. By simultaneous patch clamp pair recordings of unitary synaptic currents, live-imaging of presynaptic vesicle release and confocal microscopy, we report that GO nanosheets altered the probability of release enhancing the extinction of synaptic plasticity in the amygdala. These findings show that the modulation of presynaptic glutamate release might represent an unexplored target for (nano)pharmacological interventions of stress-related disorders.
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Affiliation(s)
- Elisa Pati
- Neuroscience Area, International School for Advanced Studies (SISSA/ISAS), 34136 Trieste, Italy.
| | | | - Raffaele Casani
- Neuroscience Area, International School for Advanced Studies (SISSA/ISAS), 34136 Trieste, Italy.
| | - Neus Lozano
- Nanomedicine Lab Catalan Institute of Nanoscience and Nanotechnology (ICN2), CSIC and BIST, Campus UAB, Bellaterra, 08193 Barcelona, Spain
| | - Kostas Kostarelos
- Nanomedicine Lab Catalan Institute of Nanoscience and Nanotechnology (ICN2), CSIC and BIST, Campus UAB, Bellaterra, 08193 Barcelona, Spain
- Nanomedicine Lab, and Faculty of Biology, Medicine & Health, The National Graphene Institute, University of Manchester, Manchester, M13 9PL, UK
| | - Giada Cellot
- Neuroscience Area, International School for Advanced Studies (SISSA/ISAS), 34136 Trieste, Italy.
| | - Laura Ballerini
- Neuroscience Area, International School for Advanced Studies (SISSA/ISAS), 34136 Trieste, Italy.
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Leite JA, Orellana AM, Andreotti DZ, Matumoto AM, de Souza Ports NM, de Sá Lima L, Kawamoto EM, Munhoz CD, Scavone C. Ouabain Reverts CUS-Induced Disruption of the HPA Axis and Avoids Long-Term Spatial Memory Deficits. Biomedicines 2023; 11:biomedicines11041177. [PMID: 37189795 DOI: 10.3390/biomedicines11041177] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2023] [Revised: 03/17/2023] [Accepted: 03/22/2023] [Indexed: 05/17/2023] Open
Abstract
Ouabain (OUA) is a cardiotonic steroid that modulates Na+, K+ -ATPase activity. OUA has been identified as an endogenous substance that is present in human plasma, and it has been shown to be associated with the response to acute stress in both animals and humans. Chronic stress is a major aggravating factor in psychiatric disorders, including depression and anxiety. The present work investigates the effects of the intermittent administration of OUA (1.8 μg/kg) during the chronic unpredictable stress (CUS) protocol in a rat's central nervous system (CNS). The results suggest that the intermittent OUA treatment reversed CUS-induced HPA axis hyperactivity through a reduction in (i) glucocorticoids levels, (ii) CRH-CRHR1 expression, and by decreasing neuroinflammation with a reduction in iNOS activity, without interfering with the expression of antioxidant enzymes. These changes in both the hypothalamus and hippocampus may reflect in the rapid extinction of aversive memory. The present data demonstrate the ability of OUA to modulate the HPA axis, as well as to revert CUS-induced long-term spatial memory deficits.
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Affiliation(s)
- Jacqueline Alves Leite
- Departament of Pharmacology, Institute of Biomedical Sciences, University of São Paulo, São Paulo 05508-000, Brazil
- Department of Pharmacology, Institute of Biological Sciences, Universidade Federal de Goiás, Goiânia 74690-900, Brazil
| | - Ana Maria Orellana
- Departament of Pharmacology, Institute of Biomedical Sciences, University of São Paulo, São Paulo 05508-000, Brazil
| | - Diana Zukas Andreotti
- Departament of Pharmacology, Institute of Biomedical Sciences, University of São Paulo, São Paulo 05508-000, Brazil
| | - Amanda Midori Matumoto
- Departament of Pharmacology, Institute of Biomedical Sciences, University of São Paulo, São Paulo 05508-000, Brazil
| | | | - Larissa de Sá Lima
- Departament of Pharmacology, Institute of Biomedical Sciences, University of São Paulo, São Paulo 05508-000, Brazil
| | - Elisa Mitiko Kawamoto
- Departament of Pharmacology, Institute of Biomedical Sciences, University of São Paulo, São Paulo 05508-000, Brazil
| | - Carolina Demarchi Munhoz
- Departament of Pharmacology, Institute of Biomedical Sciences, University of São Paulo, São Paulo 05508-000, Brazil
| | - Cristoforo Scavone
- Departament of Pharmacology, Institute of Biomedical Sciences, University of São Paulo, São Paulo 05508-000, Brazil
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Maren S. Unrelenting Fear Under Stress: Neural Circuits and Mechanisms for the Immediate Extinction Deficit. Front Syst Neurosci 2022; 16:888461. [PMID: 35520882 PMCID: PMC9062589 DOI: 10.3389/fnsys.2022.888461] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2022] [Accepted: 03/22/2022] [Indexed: 11/13/2022] Open
Abstract
Therapeutic interventions for disorders of fear and anxiety rely on behavioral approaches that reduce pathological fear memories. For example, learning that threat-predictive stimuli are no longer associated with aversive outcomes is central to the extinction of conditioned fear responses. Unfortunately, fear memories are durable, long-lasting, and resistant to extinction, particularly under high levels of stress. This is illustrated by the “immediate extinction deficit,” which is characterized by a poor long-term reduction of conditioned fear when extinction procedures are attempted within hours of fear conditioning. Here, I will review recent work that has provided new insight into the neural mechanisms underlying resistance to fear extinction. Emerging studies reveal that locus coeruleus norepinephrine modulates amygdala-prefrontal cortical circuits that are critical for extinction learning. These data suggest that stress-induced activation of brain neuromodulatory systems biases fear memory at the expense of extinction learning. Behavioral and pharmacological strategies to reduce stress in patients undergoing exposure therapy might improve therapeutic outcomes.
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Chakraborty P, Chattarji S, Jeanneteau F. A salience hypothesis of stress in PTSD. Eur J Neurosci 2021; 54:8029-8051. [PMID: 34766390 DOI: 10.1111/ejn.15526] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2021] [Revised: 09/13/2021] [Accepted: 10/30/2021] [Indexed: 11/30/2022]
Abstract
Attention to key features of contexts and things is a necessary tool for all organisms. Detecting these salient features of cues, or simply, salience, can also be affected by exposure to traumatic stress, as has been widely reported in individuals suffering from post-traumatic stress disorder (PTSD). Interestingly, similar observations have been robustly replicated across many animal models of stress as well. By using evidence from such rodent stress paradigms, in the present review, we explore PTSD through the lens of salience processing. In this context, we propose that interaction between the neurotrophin brain-derived neurotrophic factor (BDNF) and glucocorticoids determines the long lasting cellular and behavioural consequences of stress salience. We also describe the dual effect of glucocorticoid therapy in the amelioration of PTSD symptoms. Finally, by integrating in vivo observations at multiple scales of plasticity, we propose a unifying hypothesis that pivots on a crucial role of glucocorticoid signalling in dynamically orchestrating stress salience.
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Affiliation(s)
- Prabahan Chakraborty
- Institut de Genomique Fonctionnelle, University of Montpellier, Inserm, CNRS, Montpellier, 34090, France.,Tata Institute of Fundamental Research, National Centre for Biological Sciences, Bellary Road, Bangalore, 560065, India
| | - Sumantra Chattarji
- Tata Institute of Fundamental Research, National Centre for Biological Sciences, Bellary Road, Bangalore, 560065, India.,Centre for Brain Development and Repair, Institute for Stem Cell Biology and Regenerative Medicine, Bangalore, India.,Centre for Discovery Brain Sciences, Deanery of Biomedical Sciences, University of Edinburgh, Edinburgh, UK
| | - Freddy Jeanneteau
- Institut de Genomique Fonctionnelle, University of Montpellier, Inserm, CNRS, Montpellier, 34090, France
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Stress, memory, and implications for major depression. Behav Brain Res 2021; 412:113410. [PMID: 34116119 DOI: 10.1016/j.bbr.2021.113410] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2020] [Revised: 06/04/2021] [Accepted: 06/06/2021] [Indexed: 12/22/2022]
Abstract
The stress response comprises a phylogenetically conserved set of cognitive, physiological, and behavioral responses that evolved as a survival strategy. In this context, the memory of stressful events would be adaptive as it could avoid re-exposure to an adverse event, otherwise the event would be facilitated in positively stressful or non-distressful conditions. However, the interaction between stress and memory comprises complex responses, some of them which are not yet completely understood, and which depend on several factors such as the memory system that is recruited, the nature and duration of the stressful event, as well as the timing in which this interaction takes place. In this narrative review, we briefly discuss the mechanisms of the stress response, the main memory systems, and its neural correlates. Then, we show how stress, through the action of its biochemical mediators, influences memory systems and mnemonic processes. Finally, we make use of major depressive disorder to explore the possible implications of non-adaptive interactions between stress and memory to psychiatric disorders, as well as possible roles for memory studies in the field of psychiatry.
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Franceschi Biagioni A, Cellot G, Pati E, Lozano N, Ballesteros B, Casani R, Coimbra NC, Kostarelos K, Ballerini L. Graphene oxide prevents lateral amygdala dysfunctional synaptic plasticity and reverts long lasting anxiety behavior in rats. Biomaterials 2021; 271:120749. [PMID: 33714913 DOI: 10.1016/j.biomaterials.2021.120749] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Revised: 02/23/2021] [Accepted: 02/27/2021] [Indexed: 12/19/2022]
Abstract
Engineered small graphene oxide (s-GO) sheets were previously shown to reversibly down-regulate glutamatergic synapses in the hippocampus of juvenile rats, disclosing an unexpected translational potential of these nanomaterials to target selective synapses in vivo. Synapses are anatomical specializations acting in the Central Nervous System (CNS) as functional interfaces among neurons. Dynamic changes in synaptic function, named synaptic plasticity, are crucial to learning and memory. More recently, pathological mechanisms involving dysfunctional synaptic plasticity were implicated in several brain diseases, from dementia to anxiety disorders. Hyper-excitability of glutamatergic neurons in the lateral nucleus of the amygdala complex (LA) is substantially involved in the storage of aversive memory induced by stressful events enabling post-traumatic stress disorder (PTSD). Here we translated in PTSD animal model the ability of s-GO, when stereotaxically administered to hamper LA glutamatergic transmission and to prevent the behavioral response featured in long-term aversive memory. We propose that s-GO, by interference with glutamatergic plasticity, impair LA-dependent memory retrieval related to PTSD.
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Affiliation(s)
- Audrey Franceschi Biagioni
- Neuron Physiology and Technology Lab, International School for Advanced Studies (SISSA), Neuroscience, Via Bonomea 265, 34136, Trieste, Italy
| | - Giada Cellot
- Neuron Physiology and Technology Lab, International School for Advanced Studies (SISSA), Neuroscience, Via Bonomea 265, 34136, Trieste, Italy
| | - Elisa Pati
- Neuron Physiology and Technology Lab, International School for Advanced Studies (SISSA), Neuroscience, Via Bonomea 265, 34136, Trieste, Italy
| | - Neus Lozano
- Catalan Institute of Nanoscience and Nanotechnology (ICN2), CSIC and BIST, Campus UAB, Bellaterra, 08193, Barcelona, Spain
| | - Belén Ballesteros
- Catalan Institute of Nanoscience and Nanotechnology (ICN2), CSIC and BIST, Campus UAB, Bellaterra, 08193, Barcelona, Spain
| | - Raffaele Casani
- Neuron Physiology and Technology Lab, International School for Advanced Studies (SISSA), Neuroscience, Via Bonomea 265, 34136, Trieste, Italy
| | - Norberto Cysne Coimbra
- Laboratory of Neuroanatomy & Neuropsychobiology, Department of Pharmacology, Ribeirão Preto Medical School of the University of São Paulo (FMRP-USP), Av. Bandeirantes 3900, 14049-900, Ribeirão Preto, SP, Brazil
| | - Kostas Kostarelos
- Catalan Institute of Nanoscience and Nanotechnology (ICN2), CSIC and BIST, Campus UAB, Bellaterra, 08193, Barcelona, Spain; Nanomedicine Lab, National Graphene Institute and Faculty of Biology, Medicine & Health, The University of Manchester, AV Hill Building, Oxford Rd, Manchester, M13 9PL, United Kingdom
| | - Laura Ballerini
- Neuron Physiology and Technology Lab, International School for Advanced Studies (SISSA), Neuroscience, Via Bonomea 265, 34136, Trieste, Italy.
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Chakraborty P, Datta S, McEwen BS, Chattarji S. Corticosterone after acute stress prevents the delayed effects on the amygdala. Neuropsychopharmacology 2020; 45:2139-2146. [PMID: 32629457 PMCID: PMC7784883 DOI: 10.1038/s41386-020-0758-0] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/15/2020] [Revised: 06/05/2020] [Accepted: 06/29/2020] [Indexed: 01/23/2023]
Abstract
Even a single 2-hour episode of immobilization stress is known to trigger anxiety-like behavior and increase spine-density in the basolateral amygdala (BLA) of rats 10 days later. This delayed build-up of morphological and behavioral effects offers a stress-free time window of intervention after acute stress, which we used to test a protective role for glucocorticoids against stress. We observed that post-stress corticosterone, given 1 day after acute stress in drinking water, reversed enhanced anxiety-like behavior 10 days later. Quantification of spine-density on Golgi-stained BLA principal neurons showed that the same intervention also prevented the increase in spine numbers in the amygdala, at the same delayed time-point. Further, stress elevated serum corticosterone levels in rats that received vehicle in the drinking water. However, when stress was followed 24 h later by corticosterone in the drinking water, the surge in corticosterone was prevented. Together, these observations suggest that corticosterone, delivered through drinking water even 24 h after acute stress, is capable of reversing the delayed enhancing effects on BLA synaptic connectivity and anxiety-like behavior. Strikingly, although the immobilization-induced surge in corticosterone by itself has delayed detrimental effects on amygdalar structure and function, there exists a window of opportunity even after stress to mitigate its impact with a second surge of exogenously administered corticosterone. This provides a framework in the amygdala for analyzing how the initial physiological and endocrine processes triggered by traumatic stress eventually give rise to debilitating emotional symptoms, as well as the protective effects of glucocorticoids against their development.
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Affiliation(s)
- Prabahan Chakraborty
- National Centre for Biological Sciences, Bangalore, 560065, India
- Institut de Genomique Fonctionnelle, Inserm U1191, CNRS UMR5203, University of Montpellier, Montpellier, 34090, France
| | - Siddhartha Datta
- Centre for Brain Development and Repair, Institute for Stem Cell Biology and Regenerative Medicine, Bangalore, 560065, India
| | - Bruce S McEwen
- Laboratory of Neuroendocrinology, The Rockefeller University, New York, NY, 10065, USA
| | - Sumantra Chattarji
- National Centre for Biological Sciences, Bangalore, 560065, India.
- Centre for Brain Development and Repair, Institute for Stem Cell Biology and Regenerative Medicine, Bangalore, 560065, India.
- Laboratory of Neuroendocrinology, The Rockefeller University, New York, NY, 10065, USA.
- Centre for Discovery Brain Sciences, Deanery of Biomedical Sciences, University of Edinburgh, Hugh Robson Building, 15 George Square, Edinburgh, EH89XD, UK.
- National Centre for Biological Sciences, GKVK Campus, Bellary Road, Bangalore, Karnataka, 560065, India.
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Jung SH, Meckes JK, Schipma MJ, Lim PH, Jenz ST, Przybyl K, Wert SL, Kim S, Luo W, Gacek SA, Jankord R, Hatcher-Solis C, Redei EE. Strain Differences in Responsiveness to Repeated Restraint Stress Affect Remote Contextual Fear Memory and Blood Transcriptomics. Neuroscience 2020; 444:76-91. [PMID: 32768618 DOI: 10.1016/j.neuroscience.2020.07.052] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2020] [Revised: 07/15/2020] [Accepted: 07/29/2020] [Indexed: 12/20/2022]
Abstract
The role of stress in altering fear memory is not well understood. Since individual variations in stress reactivity exist, and stress alters fear memory, exposing individuals with differing stress-reactivity to repeated stress would affect their fear memory to various degrees. We explored this question using the average stress-reactive Fisher 344 (F344) rat strain and the Wistar-Kyoto (WKY) strain with its heightened stress-reactivity. Male F344 and WKY rats were exposed to the contextual fear conditioning (CFC) paradigm and then chronic restraint stress (CRS) or no stress (NS) was administered for two weeks before a second CFC. Both recent and reinstated fear memory were greater in F344s than WKYs, regardless of the stress status. In contrast, remote memory was attenuated only in F344s after CRS. In determining whether this strain-specific response to CRS was mirrored by transcriptomic changes in the blood, RNA sequencing was carried out. Overlapping differentially expressed genes (DEGs) between NS and CRS in the blood of F344 and WKY suggest a convergence of stress-related molecular mechanisms, independent of stress-reactivity. In contrast, DEGs unique to the F344 and the WKY stress responses are divergent in their functionality and networks, beyond that of strain differences in their non-stressed state. These results suggest that in some individuals chronic or repeated stress, different from the original fear memory-provoking stress, can attenuate prior fear memory. Furthermore, the novel blood DEGs can report on the general state of stress of the individual, or can be associated with individual variation in stress-responsiveness.
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Affiliation(s)
- Seung H Jung
- Applied Neuroscience, 711th Human Performance Wing, Air Force Research Laboratory, Wright-Patterson Air Force Base, OH, USA
| | - Jeanie K Meckes
- Department of Psychiatry and Behavioral Sciences, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA
| | - Matthew J Schipma
- NUSeq Core, Center for Genetic Medicine, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA
| | - Patrick H Lim
- Department of Psychiatry and Behavioral Sciences, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA
| | - Sophia T Jenz
- Department of Psychiatry and Behavioral Sciences, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA
| | - Katherine Przybyl
- Department of Psychiatry and Behavioral Sciences, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA
| | - Stephanie L Wert
- Department of Psychiatry and Behavioral Sciences, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA
| | - Sarah Kim
- Department of Psychiatry and Behavioral Sciences, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA
| | - Wendy Luo
- Department of Psychiatry and Behavioral Sciences, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA
| | - Stephanie A Gacek
- Department of Psychiatry and Behavioral Sciences, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA
| | - Ryan Jankord
- Applied Neuroscience, 711th Human Performance Wing, Air Force Research Laboratory, Wright-Patterson Air Force Base, OH, USA
| | - Candice Hatcher-Solis
- Applied Neuroscience, 711th Human Performance Wing, Air Force Research Laboratory, Wright-Patterson Air Force Base, OH, USA
| | - Eva E Redei
- Department of Psychiatry and Behavioral Sciences, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA.
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Endogenous in-session cortisol during exposure therapy predicts symptom improvement: Preliminary results from a scopolamine-augmentation trial. Psychoneuroendocrinology 2020; 116:104657. [PMID: 32244170 PMCID: PMC7293922 DOI: 10.1016/j.psyneuen.2020.104657] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/07/2019] [Revised: 03/16/2020] [Accepted: 03/18/2020] [Indexed: 01/04/2023]
Abstract
The purpose of this study was to explore whether individual differences in glucocorticoid concentrations were associated with symptom improvement following exposure therapy for patients with social anxiety disorder. To do this, 60 participants with social anxiety disorder completed a randomized-controlled trial of exposure therapy, where participants were randomized to receive scopolamine-augmentation or placebo during their 7 exposure sessions. Scopolamine is an antimuscarinic which blocks the effects of acetylcholine and reduces autonomic arousal. During sessions 1, 4, 7, and during the post-treatment extinction assessment, participants provided up to 16 saliva samples (4 in each session). Pre-treatment, post-treatment, and at 1-month follow-up, participants completed the Liebowitz Social Anxiety Scale to monitor change in fear and avoidance symptoms. Elevated endogenous in-session cortisol during exposure sessions was associated with less symptom improvement from pre- to post-treatment and at 1-month follow-up. The association between elevated endogenous in-session cortisol and attenuated symptom change was not moderated by scopolamine treatment condition. Individuals with social anxiety disorder who have elevated neuroendocrine signaling may under-benefit from exposure therapy. This is the first study, to our knowledge, to examine whether endogenous in-session cortisol concentrations predict symptom changes following exposure therapy for the treatment of social anxiety disorder. More investigation of non-invasive and reliable biological markers that explain variability in responses to effective treatments are needed.
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Patel D, Kas MJ, Chattarji S, Buwalda B. Rodent models of social stress and neuronal plasticity: Relevance to depressive-like disorders. Behav Brain Res 2019; 369:111900. [DOI: 10.1016/j.bbr.2019.111900] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2019] [Revised: 03/26/2019] [Accepted: 04/09/2019] [Indexed: 12/11/2022]
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Interventions after acute stress prevent its delayed effects on the amygdala. Neurobiol Stress 2019; 10:100168. [PMID: 31193585 PMCID: PMC6535648 DOI: 10.1016/j.ynstr.2019.100168] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2018] [Revised: 04/26/2019] [Accepted: 04/29/2019] [Indexed: 11/23/2022] Open
Abstract
Stress is known to elicit contrasting patterns of plasticity in the amygdala and hippocampus. While chronic stress leads to neuronal atrophy in the rodent hippocampus, it has the opposite effect in the basolateral amygdala (BLA). Further, even a single episode of acute stress is known to elicit delayed effects in the amygdala. For example, 2 h of immobilisation stress has been shown to cause a delayed increase in dendritic spine density on BLA principal neurons 10 days later in young rats. This is paralleled by higher anxiety-like behaviour at the same delayed time point. This temporal build-up of morphological and behavioural effects 10 days later, in turn, provides a stress-free time window of intervention after exposure to acute stress. Here, we explore this possibility by specifically testing the efficacy of an anxiolytic drug in reversing the delayed effects of acute immobilisation stress. Oral gavage of diazepam 1 h after immobilisation stress prevented the increase in anxiety-like behaviour on the elevated plus-maze 10 days later. The same post-stress intervention also prevented delayed spinogenesis in the BLA 10 days after acute stress. Surprisingly, gavage of only the vehicle also had a protective effect on both the behavioural and synaptic effects of stress 10 days later. Vehicle gavage was found to trigger a significant rise in corticosterone levels that was comparable to that elicited by acute stress. This suggests that a surge in corticosterone levels, caused by the vehicle gavage 1 h after acute stress, was capable of reversing the delayed enhancing effects of stress on anxiety-like behaviour and BLA synaptic connectivity. These findings are consistent with clinical reports on the protective effects of glucocorticoids against the development of symptoms of post-traumatic stress disorder. Taken together, these results reveal strategies, targeted 1 h after stress, which can prevent the delayed effects of a brief exposure to a severe physical stressor. Acute immobilisation stress increases anxiety and BLA spinogenesis 10 days later. Oral gavage of diazepam 1 h after stress prevents both these delayed effects. Oral gavage of vehicle also has a similar protective effect on anxiety and spines. Vehicle-gavage administration leads to an increase in levels of corticosterone. This post-stress corticosterone surge may have prevented stress-effects 10 days later.
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Affiliation(s)
- Amy L Milton
- Department of Psychology, University of Cambridge, Downing Site, Cambridge, CB2 3EB, UK.
| | - Andrew Holmes
- Laboratory of Behavioral and Genomic Neuroscience, National Institute on Alcohol Abuse and Alcoholism, NIH, Bethesda, MD, USA
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