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Suryavanshi P, Langton R, Fairhead K, Glykys J. Brief and diverse excitotoxic insults cause an increase in neuronal nuclear membrane permeability in the neonatal brain. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2023.08.22.554167. [PMID: 37662276 PMCID: PMC10473591 DOI: 10.1101/2023.08.22.554167] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/05/2023]
Abstract
Neuronal swelling after excitotoxic insults is implicated in neuronal injury and death in the developing brain, yet mitigating brain edema with osmotic and surgical interventions yields poor clinical outcomes. Importantly, neuronal swelling and its downstream consequences during early brain development remain poorly investigated. Using multiphoton Ca2+ imaging in vivo (P12-17) and in acute brain slices (P8-12), we explored Ca2+-dependent downstream effects after neuronal cytotoxic edema. We observed the translocation of cytosolic GCaMP6s into the nucleus of a subpopulation of neurons minutes after various excitotoxic insults. We used automated morphology-detection algorithms for neuronal segmentation and quantified the nuclear translocation of GCaMP6s as the ratio of nuclear and cytosolic intensity (N/C ratio). Elevated neuronal N/C ratios were correlated to higher Ca2+ loads and could occur independently of neuronal swelling. Electron microscopy revealed that the nuclear translocation was associated with increased nuclear pore size. Inhibiting calpains prevented elevated N/C ratios and neuronal swelling. Thus, our results indicate altered nuclear transport in a subpopulation of neurons shortly after injury in the developing brain, which can be used as an early biomarker of acute neuronal injury.
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Affiliation(s)
- P Suryavanshi
- Department of Pediatrics, University of Iowa, Iowa City, IA
- Iowa Neuroscience Institute, University of Iowa, Iowa City, IA
| | - R Langton
- Department of Pediatrics, University of Iowa, Iowa City, IA
- Iowa Neuroscience Institute, University of Iowa, Iowa City, IA
| | - K Fairhead
- Biomedical Sciences, College of Liberal Arts and Sciences, University of Iowa, Iowa City, IA
| | - J Glykys
- Department of Pediatrics, University of Iowa, Iowa City, IA
- Iowa Neuroscience Institute, University of Iowa, Iowa City, IA
- Department of Neurology, University of Iowa, Iowa City, IA
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2
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Ollen-Bittle N, Lowry CA, Donovan KE, Andrew RD, Whitehead SN. Validating MALDI-IMS Feasibility in Ex Vivo Brain Slices. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2023. [PMID: 37471497 DOI: 10.1021/jasms.3c00152] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/22/2023]
Abstract
Matrix-assisted laser desorption ionization imaging mass spectrometry (MALDI-IMS) generates unique mass spectra in X/Y coordinates across a tissue sample, thus allowing for the spatial detection and relative quantification of biologic compounds in situ. The soft ionization of MALDI-IMS makes it an ideal technique for high-resolution imaging of complex lipid species. Lipid-based spatial chemical maps derived from MALDI-IMS provide critical insight into the unique molecular profiles of a variety of neurologic diseases. Ex vivo brain slice preparations are a prominent alternative to in vivo animal models for studying many different neurologic conditions. For the first time, we present a feasible protocol for achieving reproducible lipidomic MALDI-IMS data from ex vivo rat brain slices and provide evidence that ex vivo brain slices maintain spatiochemical lipidomic profiles representative of an intact whole brain. We conducted a methods comparison assessing the lipid profiles within the neocortex, striatum, and corpus callosum between coronal sections taken from ex vivo brain slices and the current gold standard tissue preparation method, fresh frozen whole brains. For the first time we demonstrate a technique by which 400 μm ex vivo brain slices can be extracted from an imaging chamber and prepared for MALDI-IMS in a way that preserves their lipidomic integrity. We demonstrate the feasibility of MALDI-IMS in ex vivo brain slices and provide a roadmap for MALDI-IMS utilization in uncharted neuroscience fields.
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Affiliation(s)
- Nikita Ollen-Bittle
- Department of Anatomy and Cell Biology, Western University, London, Ontario N6A 5C1, Canada
| | - Chloe A Lowry
- Centre for Neuroscience Studies, Queen's University, Kingston, Ontario K7L 3N6, Canada
| | - Katherine E Donovan
- Department of Chemistry, Queen's University, Kingston, Ontario K7L 3N6, Canada
| | - R David Andrew
- Centre for Neuroscience Studies, Queen's University, Kingston, Ontario K7L 3N6, Canada
| | - Shawn N Whitehead
- Department of Anatomy and Cell Biology, Western University, London, Ontario N6A 5C1, Canada
- Deparment of Clinical Neurological Sciences, Western University, London, Ontario N6A 5C1, Canada
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3
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Escobar I, Xu J, Jackson CW, Stegelmann SD, Fagerli EA, Dave KR, Perez-Pinzon MA. Resveratrol Preconditioning Protects Against Ischemia-Induced Synaptic Dysfunction and Cofilin Hyperactivation in the Mouse Hippocampal Slice. Neurotherapeutics 2023; 20:1177-1197. [PMID: 37208551 PMCID: PMC10457274 DOI: 10.1007/s13311-023-01386-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/23/2023] [Indexed: 05/21/2023] Open
Abstract
Perturbations in synaptic function are major determinants of several neurological diseases and have been associated with cognitive impairments after cerebral ischemia (CI). Although the mechanisms underlying CI-induced synaptic dysfunction have not been well defined, evidence suggests that early hyperactivation of the actin-binding protein, cofilin, plays a role. Given that synaptic impairments manifest shortly after CI, prophylactic strategies may offer a better approach to prevent/mitigate synaptic damage following an ischemic event. Our laboratory has previously demonstrated that resveratrol preconditioning (RPC) promotes cerebral ischemic tolerance, with many groups highlighting beneficial effects of resveratrol treatment on synaptic and cognitive function in other neurological conditions. Herein, we hypothesized that RPC would mitigate hippocampal synaptic dysfunction and pathological cofilin hyperactivation in an ex vivo model of ischemia. Various electrophysiological parameters and synaptic-related protein expression changes were measured under normal and ischemic conditions utilizing acute hippocampal slices derived from adult male mice treated with resveratrol (10 mg/kg) or vehicle 48 h prior. Remarkably, RPC significantly increased the latency to anoxic depolarization, decreased cytosolic calcium accumulation, prevented aberrant increases in synaptic transmission, and rescued deficits in long-term potentiation following ischemia. Additionally, RPC upregulated the expression of the activity-regulated cytoskeleton associated protein, Arc, which was partially required for RPC-mediated attenuation of cofilin hyperactivation. Taken together, these findings support a role for RPC in mitigating CI-induced excitotoxicity, synaptic dysfunction, and pathological over-activation of cofilin. Our study provides further insight into mechanisms underlying RPC-mediated neuroprotection against CI and implicates RPC as a promising strategy to preserve synaptic function after ischemia.
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Affiliation(s)
- Iris Escobar
- Peritz Scheinberg Cerebral Vascular Disease Research Laboratories, University of Miami Leonard M. Miller School of Medicine, PO Box 016960, Miami, FL, 33101, USA
- Department of Neurology, University of Miami Leonard M. Miller School of Medicine, PO Box 016960, Miami, FL, 33101, USA
- Neuroscience Program, University of Miami Leonard M. Miller School of Medicine, PO Box 016960, Miami, FL, 33101, USA
| | - Jing Xu
- Peritz Scheinberg Cerebral Vascular Disease Research Laboratories, University of Miami Leonard M. Miller School of Medicine, PO Box 016960, Miami, FL, 33101, USA
- Department of Neurology, University of Miami Leonard M. Miller School of Medicine, PO Box 016960, Miami, FL, 33101, USA
- Neuroscience Program, University of Miami Leonard M. Miller School of Medicine, PO Box 016960, Miami, FL, 33101, USA
| | - Charles W Jackson
- Peritz Scheinberg Cerebral Vascular Disease Research Laboratories, University of Miami Leonard M. Miller School of Medicine, PO Box 016960, Miami, FL, 33101, USA
- Department of Neurology, University of Miami Leonard M. Miller School of Medicine, PO Box 016960, Miami, FL, 33101, USA
- Neuroscience Program, University of Miami Leonard M. Miller School of Medicine, PO Box 016960, Miami, FL, 33101, USA
| | - Samuel D Stegelmann
- Peritz Scheinberg Cerebral Vascular Disease Research Laboratories, University of Miami Leonard M. Miller School of Medicine, PO Box 016960, Miami, FL, 33101, USA
- Department of Neurology, University of Miami Leonard M. Miller School of Medicine, PO Box 016960, Miami, FL, 33101, USA
| | - Eric A Fagerli
- Peritz Scheinberg Cerebral Vascular Disease Research Laboratories, University of Miami Leonard M. Miller School of Medicine, PO Box 016960, Miami, FL, 33101, USA
- Department of Neurology, University of Miami Leonard M. Miller School of Medicine, PO Box 016960, Miami, FL, 33101, USA
- Neuroscience Program, University of Miami Leonard M. Miller School of Medicine, PO Box 016960, Miami, FL, 33101, USA
| | - Kunjan R Dave
- Peritz Scheinberg Cerebral Vascular Disease Research Laboratories, University of Miami Leonard M. Miller School of Medicine, PO Box 016960, Miami, FL, 33101, USA
- Department of Neurology, University of Miami Leonard M. Miller School of Medicine, PO Box 016960, Miami, FL, 33101, USA
- Neuroscience Program, University of Miami Leonard M. Miller School of Medicine, PO Box 016960, Miami, FL, 33101, USA
| | - Miguel A Perez-Pinzon
- Peritz Scheinberg Cerebral Vascular Disease Research Laboratories, University of Miami Leonard M. Miller School of Medicine, PO Box 016960, Miami, FL, 33101, USA.
- Department of Neurology, University of Miami Leonard M. Miller School of Medicine, PO Box 016960, Miami, FL, 33101, USA.
- Neuroscience Program, University of Miami Leonard M. Miller School of Medicine, PO Box 016960, Miami, FL, 33101, USA.
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4
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Amaral-Silva L, Santin JM. Synaptic modifications transform neural networks to function without oxygen. BMC Biol 2023; 21:54. [PMID: 36927477 PMCID: PMC10022038 DOI: 10.1186/s12915-023-01518-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2022] [Accepted: 01/18/2023] [Indexed: 03/18/2023] Open
Abstract
BACKGROUND Neural circuit function is highly sensitive to energetic limitations. Much like mammals, brain activity in American bullfrogs quickly fails in hypoxia. However, after emergence from overwintering, circuits transform to function for approximately 30-fold longer without oxygen using only anaerobic glycolysis for fuel, a unique trait among vertebrates considering the high cost of network activity. Here, we assessed neuronal functions that normally limit network output and identified components that undergo energetic plasticity to increase robustness in hypoxia. RESULTS In control animals, oxygen deprivation depressed excitatory synaptic drive within native circuits, which decreased postsynaptic firing to cause network failure within minutes. Assessments of evoked and spontaneous synaptic transmission showed that hypoxia impairs synaptic communication at pre- and postsynaptic loci. However, control neurons maintained membrane potentials and a capacity for firing during hypoxia, indicating that those processes do not limit network activity. After overwintering, synaptic transmission persisted in hypoxia to sustain motor function for at least 2 h. CONCLUSIONS Alterations that allow anaerobic metabolism to fuel synapses are critical for transforming a circuit to function without oxygen. Data from many vertebrate species indicate that anaerobic glycolysis cannot fuel active synapses due to the low ATP yield of this pathway. Thus, our results point to a unique strategy whereby synapses switch from oxidative to exclusively anaerobic glycolytic metabolism to preserve circuit function during prolonged energy limitations.
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Affiliation(s)
- Lara Amaral-Silva
- Division of Biological Sciences, The University of Missouri, Columbia, USA.
| | - Joseph M Santin
- Division of Biological Sciences, The University of Missouri, Columbia, USA.
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Unekawa M, Tomita Y, Masamoto K, Kanno I, Nakahara J, Izawa Y. Close association between spreading depolarization and development of infarction under experimental ischemia in anesthetized male mice. Brain Res 2022; 1792:148023. [PMID: 35901965 DOI: 10.1016/j.brainres.2022.148023] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2022] [Revised: 07/20/2022] [Accepted: 07/21/2022] [Indexed: 11/02/2022]
Abstract
Clinical and experimental evidence suggests that spreading depolarizations (SD) usually occur in patients with ischemic or hemorrhagic stroke when the gray matter of the brain is affected. In this study, we evaluated spatiotemporal changes of cerebral blood flow (CBF) during middle cerebral artery (MCA) occlusion and examined the relationship between SD occurrence and cerebral infarct development. In male isoflurane-anesthetized C57BL/6J mice, CBF changes over the ipsilateral parietal bone were recorded by laser speckle flowgraphy during and after transient (45 min, n = 22) or permanent occlusion (n = 22) of the distal MCA. Infarct volume was evaluated 24 hr after the operation. Upon MCA occlusion, CBF decreased by -55.6 ± 8.5 % in the lowest CBF and linearly recovered with increasing distance from the region. At 1-10 min after onset of occlusion, SD occurred and concentrically propagated from the core region, showing a decrease of CBF in the whole observed area along with a transient hyperemia and oligemia in the normal region. SD spontaneously re-occurred and propagated around the ischemic area in 37 % of mice, accompanied with a marked decrease of CBF in the core or a marked increase of CBF in the normal region. The CBF response to SDs gradually changed from the core to the normal area, depending upon the distance from the core region. Infarction was not observed in transiently (n = 2) or permanently (n = 4) occluded mice without SD. The infarct area tended to be larger with increasing number of SDs in transiently occluded mice. In conclusion, our findings suggest that the occurrence of SD during ischemia might elicit infarct formation and/or influence infarct development.
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Affiliation(s)
- Miyuki Unekawa
- Department of Neurology, Keio University School of Medicine, Shinjuku, Tokyo 160-8582, Japan.
| | - Yutaka Tomita
- Department of Neurology, Keio University School of Medicine, Shinjuku, Tokyo 160-8582, Japan
| | - Kazuto Masamoto
- Center for Neuroscience and Biomedical Engineering, University of Electro-Communications, Chofu, Tokyo 182-8585, Japan; Department of Functional Brain Imaging, National Institutes for Quantum Science and Technology, Inage, Chiba 263-8555, Japan
| | - Iwao Kanno
- Department of Functional Brain Imaging, National Institutes for Quantum Science and Technology, Inage, Chiba 263-8555, Japan
| | - Jin Nakahara
- Department of Neurology, Keio University School of Medicine, Shinjuku, Tokyo 160-8582, Japan
| | - Yoshikane Izawa
- Department of Neurology, Keio University School of Medicine, Shinjuku, Tokyo 160-8582, Japan
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Tauskela JS, Brunette E, Aylsworth A, Zhao X. Neuroprotection against supra-lethal 'stroke in a dish' insults by an anti-excitotoxic receptor antagonist cocktail. Neurochem Int 2022; 158:105381. [PMID: 35764225 DOI: 10.1016/j.neuint.2022.105381] [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: 04/28/2022] [Revised: 06/07/2022] [Accepted: 06/19/2022] [Indexed: 10/17/2022]
Abstract
The goal of this study was to identify cocktails of drugs able to protect cultured rodent cortical neurons against increasing durations of oxygen-glucose deprivation (OGD). As expected, a cocktail composed of an NMDA and AMPA receptor antagonists and a voltage gated Ca2+ channel blocker (MK-801, CNQX and nifedipine, respectively) provided complete neuroprotection against mild OGD. Increasingly longer durations of OGD necessitated increasing the doses of MK-801 and CNQX, until these cocktails ultimately failed to provide neuroprotection against supra-lethal OGD, even at maximal drug concentrations. Surprisingly, supplementation of any of these cocktails with blockers of TRPM7 channels for increasing OGD durations was not neuroprotective, unless these blockers possessed the ability to inhibit NMDA receptors. Supplementation of the maximally effective cocktail with other NMDA receptor antagonists augmented neuroprotection, suggesting insufficient NMDAR blockade by MK-801. Substitution of MK-801 in cocktails with high concentrations of a glycine site NMDA receptor antagonist caused the greatest improvements in neuroprotection, with the more potent SM-31900 superior to L689,560. Substitution of CQNX in cocktails with AMPA receptor antagonists at high concentrations also improved neuroprotection, particularly with the combination of SYM 2206 and NBQX. The most neuroprotective cocktail was thus composed of SM-31900, SYM2206, NBQX, nifedipine and the antioxidant trolox. Thus, the cumulative properties of antagonist potency and concentration in a cocktail dictate neuroprotective efficacy. The central target of supra-lethal OGD is excitotoxicity, which must be blocked to the greatest extent possible to minimize ion influx.
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Affiliation(s)
- Joseph S Tauskela
- National Research Council of Canada, Human Health Therapeutics, Building M-54, 1200 Montreal Road, Ottawa, ON, Canada, K1A 0R6.
| | - Eric Brunette
- National Research Council of Canada, Human Health Therapeutics, Building M-54, 1200 Montreal Road, Ottawa, ON, Canada, K1A 0R6
| | - Amy Aylsworth
- National Research Council of Canada, Human Health Therapeutics, Building M-54, 1200 Montreal Road, Ottawa, ON, Canada, K1A 0R6
| | - Xigeng Zhao
- National Research Council of Canada, Human Health Therapeutics, Building M-54, 1200 Montreal Road, Ottawa, ON, Canada, K1A 0R6
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Andrew RD, Farkas E, Hartings JA, Brennan KC, Herreras O, Müller M, Kirov SA, Ayata C, Ollen-Bittle N, Reiffurth C, Revah O, Robertson RM, Dawson-Scully KD, Ullah G, Dreier JP. Questioning Glutamate Excitotoxicity in Acute Brain Damage: The Importance of Spreading Depolarization. Neurocrit Care 2022; 37:11-30. [PMID: 35194729 PMCID: PMC9259542 DOI: 10.1007/s12028-021-01429-4] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2021] [Accepted: 12/20/2021] [Indexed: 02/02/2023]
Abstract
BACKGROUND Within 2 min of severe ischemia, spreading depolarization (SD) propagates like a wave through compromised gray matter of the higher brain. More SDs arise over hours in adjacent tissue, expanding the neuronal damage. This period represents a therapeutic window to inhibit SD and so reduce impending tissue injury. Yet most neuroscientists assume that the course of early brain injury can be explained by glutamate excitotoxicity, the concept that immediate glutamate release promotes early and downstream brain injury. There are many problems with glutamate release being the unseen culprit, the most practical being that the concept has yielded zero therapeutics over the past 30 years. But the basic science is also flawed, arising from dubious foundational observations beginning in the 1950s METHODS: Literature pertaining to excitotoxicity and to SD over the past 60 years is critiqued. RESULTS Excitotoxicity theory centers on the immediate and excessive release of glutamate with resulting neuronal hyperexcitation. This instigates poststroke cascades with subsequent secondary neuronal injury. By contrast, SD theory argues that although SD evokes some brief glutamate release, acute neuronal damage and the subsequent cascade of injury to neurons are elicited by the metabolic stress of SD, not by excessive glutamate release. The challenge we present here is to find new clinical targets based on more informed basic science. This is motivated by the continuing failure by neuroscientists and by industry to develop drugs that can reduce brain injury following ischemic stroke, traumatic brain injury, or sudden cardiac arrest. One important step is to recognize that SD plays a central role in promoting early neuronal damage. We argue that uncovering the molecular biology of SD initiation and propagation is essential because ischemic neurons are usually not acutely injured unless SD propagates through them. The role of glutamate excitotoxicity theory and how it has shaped SD research is then addressed, followed by a critique of its fading relevance to the study of brain injury. CONCLUSIONS Spreading depolarizations better account for the acute neuronal injury arising from brain ischemia than does the early and excessive release of glutamate.
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Affiliation(s)
| | - Eszter Farkas
- Hungarian Centre of Excellence for Molecular Medicine-University of Szeged, Cerebral Blood Flow and Metabolism Research Group, Department of Cell Biology and Molecular Medicine, University of Szeged, Szeged, Hungary
| | | | | | | | | | | | - Cenk Ayata
- Harvard Medical School, Harvard University, Boston, MA USA
| | | | - Clemens Reiffurth
- Center for Stroke Research Berlin, Berlin, Germany ,Department of Experimental Neurology, Charité – Universitätsmedizin Berlin, Berlin, Germany
| | - Omer Revah
- School of Medicine, Stanford University, Stanford, CA USA
| | | | | | | | - Jens P. Dreier
- Center for Stroke Research Berlin, Berlin, Germany ,Department of Experimental Neurology, Charité – Universitätsmedizin Berlin, Berlin, Germany ,Department of Neurology, Charité – Universitätsmedizin Berlin, Berlin, Germany ,Department of Neurology, Corporate Member of Freie Universität Berlin, Berlin, Germany ,Department of Neurology, Humboldt-Universität zu Berlin, Berlin, Germany ,Department of Neurology, Berlin Institute of Health, Berlin, Germany ,Bernstein Center for Computational Neuroscience Berlin, Berlin, Germany ,Einstein Center for Neurosciences Berlin, Berlin, Germany
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Andrew RD, Hartings JA, Ayata C, Brennan KC, Dawson-Scully KD, Farkas E, Herreras O, Kirov SA, Müller M, Ollen-Bittle N, Reiffurth C, Revah O, Robertson RM, Shuttleworth CW, Ullah G, Dreier JP. The Critical Role of Spreading Depolarizations in Early Brain Injury: Consensus and Contention. Neurocrit Care 2022; 37:83-101. [PMID: 35257321 PMCID: PMC9259543 DOI: 10.1007/s12028-021-01431-w] [Citation(s) in RCA: 27] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2021] [Accepted: 12/29/2021] [Indexed: 02/02/2023]
Abstract
BACKGROUND When a patient arrives in the emergency department following a stroke, a traumatic brain injury, or sudden cardiac arrest, there is no therapeutic drug available to help protect their jeopardized neurons. One crucial reason is that we have not identified the molecular mechanisms leading to electrical failure, neuronal swelling, and blood vessel constriction in newly injured gray matter. All three result from a process termed spreading depolarization (SD). Because we only partially understand SD, we lack molecular targets and biomarkers to help neurons survive after losing their blood flow and then undergoing recurrent SD. METHODS In this review, we introduce SD as a single or recurring event, generated in gray matter following lost blood flow, which compromises the Na+/K+ pump. Electrical recovery from each SD event requires so much energy that neurons often die over minutes and hours following initial injury, independent of extracellular glutamate. RESULTS We discuss how SD has been investigated with various pitfalls in numerous experimental preparations, how overtaxing the Na+/K+ ATPase elicits SD. Elevated K+ or glutamate are unlikely natural activators of SD. We then turn to the properties of SD itself, focusing on its initiation and propagation as well as on computer modeling. CONCLUSIONS Finally, we summarize points of consensus and contention among the authors as well as where SD research may be heading. In an accompanying review, we critique the role of the glutamate excitotoxicity theory, how it has shaped SD research, and its questionable importance to the study of early brain injury as compared with SD theory.
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Affiliation(s)
- R. David Andrew
- grid.410356.50000 0004 1936 8331Queen’s University, Kingston, ON Canada
| | - Jed A. Hartings
- grid.24827.3b0000 0001 2179 9593University of Cincinnati, Cincinnati, OH USA
| | - Cenk Ayata
- grid.38142.3c000000041936754XHarvard Medical School, Harvard University, Boston, MA USA
| | - K. C. Brennan
- grid.223827.e0000 0001 2193 0096The University of Utah, Salt Lake City, UT USA
| | | | - Eszter Farkas
- grid.9008.10000 0001 1016 96251HCEMM-USZ Cerebral Blood Flow and Metabolism Research Group, and the Department of Cell Biology and Molecular Medicine, Faculty of Science and Informatics & Faculty of Medicine, University of Szeged, Szeged, Hungary
| | - Oscar Herreras
- grid.419043.b0000 0001 2177 5516Instituto de Neurobiologia Ramon Y Cajal (Consejo Superior de Investigaciones Científicas), Madrid, Spain
| | - Sergei. A. Kirov
- grid.410427.40000 0001 2284 9329Medical College of Georgia, Augusta, GA USA
| | - Michael Müller
- grid.411984.10000 0001 0482 5331University of Göttingen, University Medical Center Göttingen, Göttingen, Germany
| | - Nikita Ollen-Bittle
- grid.39381.300000 0004 1936 8884University of Western Ontario, London, ON Canada
| | - Clemens Reiffurth
- grid.7468.d0000 0001 2248 7639Center for Stroke Research Berlin, Charité – Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health; and the Department of Experimental Neurology, Charité – Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health., Berlin, Germany
| | - Omer Revah
- grid.168010.e0000000419368956School of Medicine, Stanford University, Stanford, CA USA
| | | | | | - Ghanim Ullah
- grid.170693.a0000 0001 2353 285XUniversity of South Florida, Tampa, FL USA
| | - Jens P. Dreier
- grid.7468.d0000 0001 2248 7639Center for Stroke Research Berlin, Charité – Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health; and the Department of Experimental Neurology, Charité – Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health., Berlin, Germany
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9
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Szabó Í, Varga VÉ, Dvorácskó S, Farkas AE, Körmöczi T, Berkecz R, Kecskés S, Menyhárt Á, Frank R, Hantosi D, Cozzi NV, Frecska E, Tömböly C, Krizbai IA, Bari F, Farkas E. N,N-Dimethyltryptamine attenuates spreading depolarization and restrains neurodegeneration by sigma-1 receptor activation in the ischemic rat brain. Neuropharmacology 2021; 192:108612. [PMID: 34023338 DOI: 10.1016/j.neuropharm.2021.108612] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2021] [Revised: 04/23/2021] [Accepted: 05/13/2021] [Indexed: 12/19/2022]
Abstract
Dimethyltryptamine (DMT), an endogenous ligand of sigma-1 receptors (Sig-1Rs), acts against systemic hypoxia, but whether DMT may prevent cerebral ischemic injury is unexplored. Here global forebrain ischemia was created in anesthetized rats and aggravated with the induction of spreading depolarizations (SDs) and subsequent short hypoxia before reperfusion. Drugs (DMT, the selective Sig-1R agonist PRE-084, the Sig-1R antagonist NE-100, or the serotonin receptor antagonist asenapine) were administered intravenously alone or in combination while physiological variables and local field potential from the cerebral cortex was recorded. Neuroprotection and the cellular localization of Sig-1R were evaluated with immunocytochemistry. Plasma and brain DMT content was measured by 2D-LC-HRMS/MS. The affinity of drugs for cerebral Sig-1R was evaluated with a radioligand binding assay. Both DMT and PRE-084 mitigated SDs, counteracted with NE-100. Further, DMT attenuated SD when co-administered with asenapine, compared to asenapine alone. DMT reduced the number of apoptotic and ferroptotic cells and supported astrocyte survival. The binding affinity of DMT to Sig-1R matched previously reported values. Sig-1Rs were associated with the perinuclear cytoplasm of neurons, astrocytes and microglia, and with glial processes. According to these data, DMT may be considered as adjuvant pharmacological therapy in the management of acute cerebral ischemia.
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Affiliation(s)
- Írisz Szabó
- Department of Medical Physics and Informatics, Faculty of Medicine and Faculty of Science and Informatics, University of Szeged; Korányi Fasor 9, Szeged, 6720, Hungary.
| | - Viktória É Varga
- Department of Medical Physics and Informatics, Faculty of Medicine and Faculty of Science and Informatics, University of Szeged; Korányi Fasor 9, Szeged, 6720, Hungary.
| | - Szabolcs Dvorácskó
- Laboratory of Chemical Biology, Institute of Biochemistry, Biological Research Centre, Temesvári Krt 62, Szeged, 6726, Hungary; Department of Medical Chemistry, Faculty of Medicine, University of Szeged, Dóm Tér 8, Szeged, 6720, Hungary.
| | - Attila E Farkas
- Neurovascular Unit Research Group, Molecular Neurobiology Research Unit, Institute of Biophysics, Biological Research Centre, Temesvári Krt 62, Szeged, 6726, Hungary.
| | - Tímea Körmöczi
- Department of Medical Chemistry, Faculty of Medicine, University of Szeged, Dóm Tér 8, Szeged, 6720, Hungary; Institute of Pharmaceutical Analysis, Faculty of Pharmacy, University of Szeged, Somogyi U 4, Szeged, 6720, Hungary.
| | - Róbert Berkecz
- Department of Medical Chemistry, Faculty of Medicine, University of Szeged, Dóm Tér 8, Szeged, 6720, Hungary; Institute of Pharmaceutical Analysis, Faculty of Pharmacy, University of Szeged, Somogyi U 4, Szeged, 6720, Hungary.
| | - Szilvia Kecskés
- Department of Medical Physics and Informatics, Faculty of Medicine and Faculty of Science and Informatics, University of Szeged; Korányi Fasor 9, Szeged, 6720, Hungary.
| | - Ákos Menyhárt
- Department of Medical Physics and Informatics, Faculty of Medicine and Faculty of Science and Informatics, University of Szeged; Korányi Fasor 9, Szeged, 6720, Hungary.
| | - Rita Frank
- Department of Medical Physics and Informatics, Faculty of Medicine and Faculty of Science and Informatics, University of Szeged; Korányi Fasor 9, Szeged, 6720, Hungary.
| | - Dóra Hantosi
- Department of Medical Physics and Informatics, Faculty of Medicine and Faculty of Science and Informatics, University of Szeged; Korányi Fasor 9, Szeged, 6720, Hungary.
| | - Nicholas V Cozzi
- Neuropharmacology Laboratory, University of Wisconsin School of Medicine and Public Health, 1300 University Avenue, Madison, WI 53706, USA; Alexander Shulgin Research Institute, 1483 Shulgin Road, Lafayette, CA, 94549, USA.
| | - Ede Frecska
- Department of Psychiatry, Faculty of Medicine, University of Debrecen, Nagyerdei Krt 94, Debrecen, 4032, Hungary.
| | - Csaba Tömböly
- Laboratory of Chemical Biology, Institute of Biochemistry, Biological Research Centre, Temesvári Krt 62, Szeged, 6726, Hungary.
| | - István A Krizbai
- Neurovascular Unit Research Group, Molecular Neurobiology Research Unit, Institute of Biophysics, Biological Research Centre, Temesvári Krt 62, Szeged, 6726, Hungary; Institute of Life Sciences, UVVG, 94 Bulevardul Revoluției, Arad, 310025, Romania.
| | - Ferenc Bari
- Department of Medical Physics and Informatics, Faculty of Medicine and Faculty of Science and Informatics, University of Szeged; Korányi Fasor 9, Szeged, 6720, Hungary.
| | - Eszter Farkas
- Department of Medical Physics and Informatics, Faculty of Medicine and Faculty of Science and Informatics, University of Szeged; Korányi Fasor 9, Szeged, 6720, Hungary.
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10
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Frank R, Bari F, Menyhárt Á, Farkas E. Comparative analysis of spreading depolarizations in brain slices exposed to osmotic or metabolic stress. BMC Neurosci 2021; 22:33. [PMID: 33941084 PMCID: PMC8094470 DOI: 10.1186/s12868-021-00637-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2021] [Accepted: 04/20/2021] [Indexed: 12/21/2022] Open
Abstract
BACKGROUND Recurrent spreading depolarizations (SDs) occur in stroke and traumatic brain injury and are considered as a hallmark of injury progression. The complexity of conditions associated with SD in the living brain encouraged researchers to study SD in live brain slice preparations, yet methodological differences among laboratories complicate integrative data interpretation. Here we provide a comparative evaluation of SD evolution in live brain slices, in response to selected SD triggers and in various media, under otherwise standardized experimental conditions. METHODS Rat live coronal brain slices (350 μm) were prepared (n = 51). Hypo-osmotic medium (Na+ content reduced from 130 to 60 mM, HM) or oxygen-glucose deprivation (OGD) were applied to cause osmotic or ischemic challenge. Brain slices superfused with artificial cerebrospinal fluid (aCSF) served as control. SDs were evoked in the control condition with pressure injection of KCl or electric stimulation. Local field potential (LFP) was recorded via an intracortical glass capillary electrode, or intrinsic optical signal imaging was conducted at white light illumination to characterize SDs. TTC and hematoxylin-eosin staining were used to assess tissue damage. RESULTS Severe osmotic stress or OGD provoked a spontaneous SD. In contrast with SDs triggered in aCSF, these spontaneous depolarizations were characterized by incomplete repolarization and prolonged duration. Further, cortical SDs under HM or OGD propagated over the entire cortex and occassionally invaded the striatum, while SDs in aCSF covered a significantly smaller cortical area before coming to a halt, and never spread to the striatum. SDs in HM displayed the greatest amplitude and the most rapid propagation velocity. Finally, spontaneous SD in HM and especially under OGD was followed by tissue injury. CONCLUSIONS While the failure of Na+/K+ ATP-ase is thought to impair tissue recovery from OGD-related SD, the tissue swelling-related hyper excitability and the exhaustion of astrocyte buffering capacity are suggested to promote SD evolution under osmotic stress. In contrast with OGD, SD propagating under hypo-osmotic condition is not terminal, yet it is associated with irreversible tissue injury. Further investigation is required to understand the mechanistic similarities or differences between the evolution of SDs spontaneously occurring in HM and under OGD.
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Affiliation(s)
- Rita Frank
- Department of Medical Physics and Informatics, Faculty of Medicine and Faculty of Science and Informatics, University of Szeged, Korányi fasor 9, 6720, Szeged, Hungary
| | - Ferenc Bari
- Department of Medical Physics and Informatics, Faculty of Medicine and Faculty of Science and Informatics, University of Szeged, Korányi fasor 9, 6720, Szeged, Hungary
| | - Ákos Menyhárt
- Department of Medical Physics and Informatics, Faculty of Medicine and Faculty of Science and Informatics, University of Szeged, Korányi fasor 9, 6720, Szeged, Hungary.
| | - Eszter Farkas
- Department of Medical Physics and Informatics, Faculty of Medicine and Faculty of Science and Informatics, University of Szeged, Korányi fasor 9, 6720, Szeged, Hungary.
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11
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Reappraisal of anoxic spreading depolarization as a terminal event during oxygen-glucose deprivation in brain slices in vitro. Sci Rep 2020; 10:18970. [PMID: 33149164 PMCID: PMC7643106 DOI: 10.1038/s41598-020-75975-w] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2020] [Accepted: 10/22/2020] [Indexed: 12/20/2022] Open
Abstract
Anoxic spreading depolarization (aSD) has been hypothesized as a terminal event during oxygen–glucose deprivation (OGD) in submerged cortical slices in vitro. However, mechanical artifacts caused by aSD-triggered edema may introduce error in the assessment of neuronal viability. Here, using continuous patch-clamp recordings from submerged rat cortical slices, we first confirmed that vast majority of L4 neurons permanently lost their membrane potential during OGD-induced aSD. In some recordings, spontaneous transition from whole-cell to out-side out configuration occurred during or after aSD, and only a small fraction of neurons survived aSD with reperfusion started shortly after aSD. Secondly, to minimize artifacts caused by OGD-induced edema, cells were short-term patched following OGD episodes of various duration. Nearly half of L4 cells maintained membrane potential and showed the ability to spike-fire if reperfusion started less than 10 min after aSD. The probability of finding live neurons progressively decreased at longer reperfusion delays at a rate of about 2% per minute. We also found that neurons in L2/3 show nearly threefold higher resistance to OGD than neurons in L4. Our results suggest that in the OGD ischemia model, aSD is not a terminal event, and that the “commitment point” of irreversible damage occurs at variable delays, in the range of tens of minutes, after OGD-induced aSD in submerged cortical slices.
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12
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Lowry CA, Golod ME, Andrew RD, Bennett BM. Expression of Neuronal Na +/K +-ATPase α Subunit Isoforms in the Mouse Brain Following Genetically Programmed or Behaviourally-induced Oxidative Stress. Neuroscience 2020; 442:202-215. [PMID: 32653541 DOI: 10.1016/j.neuroscience.2020.07.009] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2020] [Revised: 06/21/2020] [Accepted: 07/04/2020] [Indexed: 12/12/2022]
Abstract
The Na+/K+-ATPase is a transmembrane ion pump that has a critical homeostatic role within every mammalian cell; however, it is vulnerable to the effects of increased oxidative stress. Understanding how expression of this transporter is influenced by oxidative stress may yield insight into its role in the pathophysiology of neurological and neuropsychiatric diseases. In this study we investigated whether increased oxidative stress could influence Na+/K+-ATPase expression in various brain regions of mice. We utilized two different models of oxidative stress: a behavioural chronic unpredictable stress protocol and the Aldh2-/- mouse model of oxidative stress-based and age-related cognitive impairment. We identified distinct regional baseline mRNA and protein expression patterns of the Na+/K+-ATPase α1 and α3 isoforms within the neocortex, hippocampus, and brainstem of wildtype mice. Consistent with previous studies, there was a higher proportion of α3 expression relative to α1 in the brainstem versus neocortex, but a higher proportion of α1 expression relative to α3 in the neocortex versus the brainstem. The hippocampus had similar expression levels of both α1 and α3. Despite increased staining for oxidative stress in higher brain, no differences in α1 or α3 expression were noted in Aldh2-/- mice versus wildtype, or in mice exposed to a 28-day chronic unpredictable stress protocol. In both models of oxidative stress, gene and protein expression of Na+/K+-ATPase α1 and α3 isoforms within the higher and lower brain was remarkably stable. Thus, Na+/K+-ATPase function previously reported as altered by oxidative stress is not through induced changes in the expression of pump isoforms.
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Affiliation(s)
- Chloe A Lowry
- Centre for Neuroscience Studies, Queen's University, 18 Stuart St., Kingston, Ontario K7L 3N6, Canada.
| | - Michael E Golod
- Centre for Neuroscience Studies, Queen's University, 18 Stuart St., Kingston, Ontario K7L 3N6, Canada.
| | - R David Andrew
- Centre for Neuroscience Studies, Queen's University, 18 Stuart St., Kingston, Ontario K7L 3N6, Canada; Department of Biomedical and Molecular Sciences, Queen's University, 18 Stuart St., Kingston, Ontario K7L 3N6, Canada.
| | - Brian M Bennett
- Centre for Neuroscience Studies, Queen's University, 18 Stuart St., Kingston, Ontario K7L 3N6, Canada; Department of Biomedical and Molecular Sciences, Queen's University, 18 Stuart St., Kingston, Ontario K7L 3N6, Canada.
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13
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Toyoda H, Kawano T, Sato H, Kato T. Cellular mechanisms underlying the rapid depolarization caused by oxygen and glucose deprivation in layer III pyramidal cells of the somatosensory cortex. Neurosci Res 2020; 164:1-9. [PMID: 32171781 DOI: 10.1016/j.neures.2020.03.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2019] [Revised: 01/29/2020] [Accepted: 03/10/2020] [Indexed: 11/29/2022]
Abstract
Cortical pyramidal neurons show rapid and irreversible membrane depolarization in response to oxygen-glucose depolarization (OGD). In this study, we investigated cellular mechanisms responsible for rapid depolarization caused by OGD in layer III pyramidal neurons of the mouse somatosensory cortex. When OGD solution was perfused in the presence of Ca2+ chelator and inhibitors of ryanodine receptors (RyRs) and inositol 1,4,5-trisphosphate receptors (IP3Rs) in the pipette solution or in the presence of inhibitors of NMDA receptors (NMDARs), voltage-gated Ca2+ channels (VGCCs), and canonical transient receptor potential (TRPC) channels in the perfusion solution, the latency of the rapid depolarization was significantly prolonged compared to the control. In addition, when OGD solution was perfused in the presence of scavengers of nitric oxide and reactive oxygen species in the perfusion solution or in the presence of calcineurin inhibitors in the pipette solution, the latency of the rapid depolarization was significantly prolonged compared to the control. These data indicate that OGD-induced intracellular Ca2+ increases mediated by Ca2+ influx through NMDARs, VGCCs and TRPC channels as well as by Ca2+ release from RyRs and IP3Rs lead to mitochondrial impairment, which may facilitate the generation of the rapid depolarization via dysfunction of Na+-K+-ATPase due to decreased ATP production.
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Affiliation(s)
- Hiroki Toyoda
- Department of Oral Physiology, Osaka University Graduate School of Dentistry, Suita, Japan.
| | - Tsutomu Kawano
- Department of Oral Physiology, Osaka University Graduate School of Dentistry, Suita, Japan
| | - Hajime Sato
- Department of Oral Physiology, Osaka University Graduate School of Dentistry, Suita, Japan
| | - Takafumi Kato
- Department of Oral Physiology, Osaka University Graduate School of Dentistry, Suita, Japan
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14
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Jirak D, Ziolkowska N, Turnovcova K, Karova K, Sykova E, Jendelova P, Romanyuk N. Metabolic Changes in Focal Brain Ischemia in Rats Treated With Human Induced Pluripotent Stem Cell-Derived Neural Precursors Confirm the Beneficial Effect of Transplanted Cells. Front Neurol 2019; 10:1074. [PMID: 31695666 PMCID: PMC6818685 DOI: 10.3389/fneur.2019.01074] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2019] [Accepted: 09/23/2019] [Indexed: 12/12/2022] Open
Abstract
There is currently no treatment for restoring lost neurological function after stroke. A growing number of studies have highlighted the potential of stem cells. However, the mechanisms underlying their beneficial effect have yet to be explored in sufficient detail. In this study, we transplanted human induced pluripotent stem cell-derived neural precursors (iPSC-NPs) in rat temporary middle cerebral artery occlusion (MCAO) model. Using magnetic resonance imaging (MRI) and magnetic resonance spectroscopy (MRS) we monitored the effect of cells and assessed lesion volume and metabolite changes in the brain. We monitored concentration changes of myo-inositol (Ins), Taurine (Tau), Glycerophosphocholine+Phosphocholine (GPC+PCh), N-acetyl-aspartate+N-acetyl-aspartyl-glutamate (NAA+NAAG), Creatine+Phosphocreatine (Cr+PCr), and Glutamate+Glutamine (Glu+Gln) in the brains of control and iPSC-NP-transplanted rats. Based on initial lesion size, animals were divided into small lesion and big lesion groups. In the small lesion control group (SCL), lesion size after 4 months was three times smaller than initial measurements. In the small lesion iPSC-NP-treated group, lesion volume decreased after 1 month and then increased after 4 months. Although animals with small lesions significantly improved their motor skills after iPSC-NP transplantation, animals with big lesions showed no improvement. However, our MRI data demonstrate that in the big lesion iPSC-NP-treated (BTL) group, lesion size increased only up until 1 month after MCAO induction and then decreased. In contrast, in the big lesion control group, lesion size increased throughout the whole experiment. Significantly higher concentrations of Ins, Tau, GPC+PCh, NAA+NAAG, Cr+PCr, and Glu+Gln were found in in contralateral hemisphere in BTL animals 4 months after cell injection. Lesion volume decreased at this time point. Spectroscopic results of metabolite concentrations in lesion correlated with volumetric measurements of lesion, with the highest negative correlation observed for NAA+NAAG. Altogether, our results suggest that iPSC-NP transplantation decreases lesion volume and regulates metabolite concentrations within the normal range expected in healthy tissue. Further research into the ability of iPSC-NPs to differentiate into tissue-specific neurons and its effect on the long-term restoration of lesioned tissue is necessary.
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Affiliation(s)
- Daniel Jirak
- MR Unit, Department of Diagnostic and Interventional Radiology, Institute for Clinical and Experimental Medicine, Prague, Czechia.,First Faculty of Medicine, Institute of Biophysics and Informatics, Charles University, Prague, Czechia.,Faculty of Health Studies, Technical University of Liberec, Liberec, Czechia
| | - Natalia Ziolkowska
- MR Unit, Department of Diagnostic and Interventional Radiology, Institute for Clinical and Experimental Medicine, Prague, Czechia.,First Faculty of Medicine, Institute of Biophysics and Informatics, Charles University, Prague, Czechia
| | - Karolina Turnovcova
- Department of Neuroregeneration, Institute of Experimental Medicine, Czech Academy of Sciences, Prague, Czechia
| | - Kristyna Karova
- Department of Neuroregeneration, Institute of Experimental Medicine, Czech Academy of Sciences, Prague, Czechia
| | - Eva Sykova
- Department of Neuroscience, Institute of Experimental Medicine, Czech Academy of Sciences, Prague, Czechia
| | - Pavla Jendelova
- Department of Neuroregeneration, Institute of Experimental Medicine, Czech Academy of Sciences, Prague, Czechia.,Department of Neuroscience, Second Faculty of Medicine, Charles University, Prague, Czechia
| | - Nataliya Romanyuk
- Department of Neuroregeneration, Institute of Experimental Medicine, Czech Academy of Sciences, Prague, Czechia
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15
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Petrin D, Gagolewicz PJ, Mehder RH, Bennett BM, Jin AY, Andrew RD. Spreading depolarization and neuronal damage or survival in mouse neocortical brain slices immediately and 12 hours following middle cerebral artery occlusion. J Neurophysiol 2019; 121:1650-1663. [PMID: 30811255 DOI: 10.1152/jn.00670.2018] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Whereas many studies have examined the properties of the compromised neocortex in the first several days following ischemia, there is less information regarding the initial 12 h poststroke. In this study we examined live mouse neocortical slices harvested immediately and 12 h after a 30-min middle cerebral artery occlusion (MCAo). We compared nonischemic and ischemic hemispheres with regard to the propensity for tissue swelling and for generating spreading depolarization (SD), as well as evoked synaptic responses and single pyramidal neuron electrophysiological properties. We observed spontaneous SD in 7% of slices on the nonstroked side and 25% in the stroked side following the 30-min MCAo. Spontaneous SD was rare in 12-h recovery slices. The region of the ischemic core and surround in slices was not susceptible to SD induced by oxygen and glucose deprivation. At the neuronal level, neocortical gray matter is surprisingly unaltered in brain slices harvested immediately poststroke. However, by 12 h, the fields of pyramidal and striatal neurons that comprise the infarcted core are electrophysiologically silent because the majority are morphologically devastated. Yet, there remains a subset of diffusely distributed "healthy" pyramidal neurons in the core at 12 h post-MCAo that persist for days poststroke. Their intact electrophysiology and dendritic morphology indicate a surprisingly selective resilience to stroke at the neuronal level. NEW & NOTEWORTHY It is generally accepted that the injured core region of the brain resulting from a focal stroke contains no functioning neurons. Our study shows that some neurons, although surrounded by devastated neighbors, can maintain their structure and electrical activity. This surprising finding raises the possibility of discovering how these neurons are protected to pinpoint new strategies for reducing stroke injury.
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Affiliation(s)
- Dylan Petrin
- Department of Biomedical and Molecular Sciences, Queen's University , Kingston, Ontario , Canada
| | - Peter J Gagolewicz
- Department of Biomedical and Molecular Sciences, Queen's University , Kingston, Ontario , Canada
| | - Rasha H Mehder
- Department of Biomedical and Molecular Sciences, Queen's University , Kingston, Ontario , Canada
| | - Brian M Bennett
- Department of Biomedical and Molecular Sciences, Queen's University , Kingston, Ontario , Canada
| | - Albert Y Jin
- Department of Biomedical and Molecular Sciences, Queen's University , Kingston, Ontario , Canada
| | - R David Andrew
- Department of Biomedical and Molecular Sciences, Queen's University , Kingston, Ontario , Canada
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16
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The hypoxia-tolerant vertebrate brain: Arresting synaptic activity. Comp Biochem Physiol B Biochem Mol Biol 2018; 224:61-70. [DOI: 10.1016/j.cbpb.2017.11.015] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2017] [Revised: 11/23/2017] [Accepted: 11/30/2017] [Indexed: 01/16/2023]
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17
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Ferrer-Acosta Y, Gonzalez-Vega MN, Rivera-Aponte DE, Martinez-Jimenez SM, Martins AH. Monitoring Astrocyte Reactivity and Proliferation in Vitro Under Ischemic-Like Conditions. J Vis Exp 2017. [PMID: 29155711 DOI: 10.3791/55108] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
Ischemic stroke is a complex brain injury caused by a thrombus or embolus obstructing blood flow to parts of the brain. This leads to deprivation of oxygen and glucose, which causes energy failure and neuronal death. After an ischemic stroke insult, astrocytes become reactive and proliferate around the injury site as it develops. Under this scenario, it is difficult to study the specific contribution of astrocytes to the brain region exposed to ischemia. Therefore, this article introduces a methodology to study primary astrocyte reactivity and proliferation under an in vitro model of an ischemia-like environment, called oxygen glucose deprivation (OGD). Astrocytes were isolated from 1-4 day-old neonatal rats and the number of non-specific astrocytic cells was assessed using astrocyte selective marker Glial Fibrillary Acidic Protein (GFAP) and nuclear staining. The period in which astrocytes are subjected to the OGD condition can be customized, as well as the percentage of oxygen they are exposed to. This flexibility allows scientists to characterize the duration of the ischemic-like condition in different groups of cells in vitro. This article discusses the timeframes of OGD that induce astrocyte reactivity, hypertrophic morphology, and proliferation as measured by immunofluorescence using Proliferating Cell Nuclear Antigen (PCNA). Besides proliferation, astrocytes undergo energy and oxidative stress, and respond to OGD by releasing soluble factors into the cell medium. This medium can be collected and used to analyze the effects of molecules released by astrocytes in primary neuronal cultures without cell-to-cell interaction. In summary, this primary cell culture model can be efficiently used to understand the role of isolated astrocytes upon injury.
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Affiliation(s)
- Yancy Ferrer-Acosta
- Department of Neuroscience, School of Medicine, Universidad Central del Caribe
| | | | | | | | - Antonio H Martins
- Department of Pharmacology and Toxicology, Medical Sciences, Campus, University of Puerto Rico;
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18
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Andrew RD, Hsieh YT, Brisson CD. Spreading depolarization triggered by elevated potassium is weak or absent in the rodent lower brain. J Cereb Blood Flow Metab 2017; 37:1735-1747. [PMID: 27381828 PMCID: PMC5435291 DOI: 10.1177/0271678x16657344] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
We examined in live coronal slices from rat and mouse which brain regions generate potassium-triggered spreading depolarization (SDKt). This technique simulates cortical spreading depression, which underlies migraine aura in the intact brain. An SDKt episode was evoked by increasing bath [K+]o and recorded as a propagating front of elevated light transmittance representing transient neuronal swelling in gray matter of neocortex, hippocampus, striatum, and thalamus. In contrast, SDKt was not imaged in hypothalamic nuclei or brainstem with exception of those nuclei near the dorsal brainstem surface. In rat slices, single neurons were whole-cell current clamped during SDKt. "Higher" neurons depolarized to near zero millivolts indicating SDKt generation. In contrast, seven types of neurons in hypothalamus and brainstem only slowly depolarized without generating SDKt, supporting our imaging findings. Therefore, SDKt is not a default of CNS neurons but rather displays a region-specific susceptibility, similar to anoxic depolarization, which we have proposed is correlated with a region's vulnerability to traumatic brain injury. In the higher brain, SDKt may be a vestigial spreading depolarization that originally evolved to shut down and vasoconstrict gray matter regions more exposed to impact and contusion.
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Affiliation(s)
- R David Andrew
- Department of Biomedical and Molecular Sciences, Queen's University, Kingston, Canada
| | - Yi-Ting Hsieh
- Department of Biomedical and Molecular Sciences, Queen's University, Kingston, Canada
| | - C Devin Brisson
- Department of Biomedical and Molecular Sciences, Queen's University, Kingston, Canada
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19
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Hartings JA, Shuttleworth CW, Kirov SA, Ayata C, Hinzman JM, Foreman B, Andrew RD, Boutelle MG, Brennan KC, Carlson AP, Dahlem MA, Drenckhahn C, Dohmen C, Fabricius M, Farkas E, Feuerstein D, Graf R, Helbok R, Lauritzen M, Major S, Oliveira-Ferreira AI, Richter F, Rosenthal ES, Sakowitz OW, Sánchez-Porras R, Santos E, Schöll M, Strong AJ, Urbach A, Westover MB, Winkler MK, Witte OW, Woitzik J, Dreier JP. The continuum of spreading depolarizations in acute cortical lesion development: Examining Leão's legacy. J Cereb Blood Flow Metab 2017; 37:1571-1594. [PMID: 27328690 PMCID: PMC5435288 DOI: 10.1177/0271678x16654495] [Citation(s) in RCA: 268] [Impact Index Per Article: 38.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
A modern understanding of how cerebral cortical lesions develop after acute brain injury is based on Aristides Leão's historic discoveries of spreading depression and asphyxial/anoxic depolarization. Treated as separate entities for decades, we now appreciate that these events define a continuum of spreading mass depolarizations, a concept that is central to understanding their pathologic effects. Within minutes of acute severe ischemia, the onset of persistent depolarization triggers the breakdown of ion homeostasis and development of cytotoxic edema. These persistent changes are diagnosed as diffusion restriction in magnetic resonance imaging and define the ischemic core. In delayed lesion growth, transient spreading depolarizations arise spontaneously in the ischemic penumbra and induce further persistent depolarization and excitotoxic damage, progressively expanding the ischemic core. The causal role of these waves in lesion development has been proven by real-time monitoring of electrophysiology, blood flow, and cytotoxic edema. The spreading depolarization continuum further applies to other models of acute cortical lesions, suggesting that it is a universal principle of cortical lesion development. These pathophysiologic concepts establish a working hypothesis for translation to human disease, where complex patterns of depolarizations are observed in acute brain injury and appear to mediate and signal ongoing secondary damage.
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Affiliation(s)
- Jed A Hartings
- 1 Department of Neurosurgery, University of Cincinnati College of Medicine, Cincinnati, OH, USA.,2 Mayfield Clinic, Cincinnati, OH, USA
| | - C William Shuttleworth
- 3 Department of Neuroscience, University of New Mexico School of Medicine, Albuquerque, NM, USA
| | - Sergei A Kirov
- 4 Department of Neurosurgery and Brain and Behavior Discovery Institute, Medical College of Georgia, Augusta, GA, USA
| | - Cenk Ayata
- 5 Neurovascular Research Unit, Department of Radiology, and Stroke Service and Neuroscience Intensive Care Unit, Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Jason M Hinzman
- 1 Department of Neurosurgery, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - Brandon Foreman
- 6 Department of Neurology and Rehabilitation Medicine, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - R David Andrew
- 7 Department of Biomedical & Molecular Sciences, Queen's University, Kingston, Ontario, Canada
| | - Martyn G Boutelle
- 8 Department of Bioengineering, Imperial College London, London, United Kingdom
| | - K C Brennan
- 9 Department of Neurology, University of Utah, Salt Lake City, UT, USA.,10 Department of Neurobiology and Anatomy, University of Utah, Salt Lake City, UT, USA
| | - Andrew P Carlson
- 11 Department of Neurosurgery, University of New Mexico School of Medicine, Albuquerque, NM, USA
| | - Markus A Dahlem
- 12 Department of Physics, Humboldt University of Berlin, Berlin, Germany
| | | | - Christian Dohmen
- 14 Department of Neurology, University of Cologne, Cologne, Germany
| | - Martin Fabricius
- 15 Department of Clinical Neurophysiology, Rigshospitalet, Glostrup, Denmark
| | - Eszter Farkas
- 16 Department of Medical Physics and Informatics, Faculty of Medicine, and Faculty of Science and Informatics, University of Szeged, Szeged, Hungary
| | - Delphine Feuerstein
- 17 Multimodal Imaging of Brain Metabolism, Max-Planck-Institute for Metabolism Research, Cologne, Germany
| | - Rudolf Graf
- 17 Multimodal Imaging of Brain Metabolism, Max-Planck-Institute for Metabolism Research, Cologne, Germany
| | - Raimund Helbok
- 18 Medical University of Innsbruck, Department of Neurology, Neurocritical Care Unit, Innsbruck, Austria
| | - Martin Lauritzen
- 15 Department of Clinical Neurophysiology, Rigshospitalet, Glostrup, Denmark.,19 Department of Neuroscience and Pharmacology and Center for Healthy Aging, University of Copenhagen, Copenhagen, Denmark
| | - Sebastian Major
- 13 Department of Neurology, Charité University Medicine, Berlin, Germany.,20 Center for Stroke Research Berlin, Charité University Medicine, Berlin, Germany.,21 Department of Experimental Neurology, Charité University Medicine, Berlin, Germany
| | - Ana I Oliveira-Ferreira
- 20 Center for Stroke Research Berlin, Charité University Medicine, Berlin, Germany.,21 Department of Experimental Neurology, Charité University Medicine, Berlin, Germany
| | - Frank Richter
- 22 Institute of Physiology/Neurophysiology, Jena University Hospital, Jena, Germany
| | - Eric S Rosenthal
- 5 Neurovascular Research Unit, Department of Radiology, and Stroke Service and Neuroscience Intensive Care Unit, Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Oliver W Sakowitz
- 23 Department of Neurosurgery, Klinikum Ludwigsburg, Ludwigsburg, Germany.,24 Department of Neurosurgery, Heidelberg University Hospital, Heidelberg, Germany
| | - Renán Sánchez-Porras
- 24 Department of Neurosurgery, Heidelberg University Hospital, Heidelberg, Germany
| | - Edgar Santos
- 24 Department of Neurosurgery, Heidelberg University Hospital, Heidelberg, Germany
| | - Michael Schöll
- 24 Department of Neurosurgery, Heidelberg University Hospital, Heidelberg, Germany
| | - Anthony J Strong
- 25 Department of Basic and Clinical Neuroscience, Institute of Psychiatry, Psychology and Neuroscience, King's College London
| | - Anja Urbach
- 26 Hans Berger Department of Neurology, Jena University Hospital, Jena, Germany
| | - M Brandon Westover
- 5 Neurovascular Research Unit, Department of Radiology, and Stroke Service and Neuroscience Intensive Care Unit, Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Maren Kl Winkler
- 20 Center for Stroke Research Berlin, Charité University Medicine, Berlin, Germany
| | - Otto W Witte
- 26 Hans Berger Department of Neurology, Jena University Hospital, Jena, Germany.,27 Brain Imaging Center, Jena University Hospital, Jena, Germany
| | - Johannes Woitzik
- 20 Center for Stroke Research Berlin, Charité University Medicine, Berlin, Germany.,28 Department of Neurosurgery, Charité University Medicine, Berlin, Germany
| | - Jens P Dreier
- 13 Department of Neurology, Charité University Medicine, Berlin, Germany.,20 Center for Stroke Research Berlin, Charité University Medicine, Berlin, Germany.,21 Department of Experimental Neurology, Charité University Medicine, Berlin, Germany
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20
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The earliest neuronal responses to hypoxia in the neocortical circuit are glutamate-dependent. Neurobiol Dis 2016; 95:158-67. [PMID: 27443966 DOI: 10.1016/j.nbd.2016.07.019] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2016] [Revised: 07/11/2016] [Accepted: 07/17/2016] [Indexed: 11/23/2022] Open
Abstract
Soon after exposure to hypoxia or ischemia, neurons in cortical tissues undergo massive anoxic depolarization (AD). This precipitous event is preceded by more subtle neuronal changes, including enhanced excitatory and inhibitory synaptic transmitter release. Here, we have used patch-in-slice techniques to identify the earliest effects of acute hypoxia on the synaptic and intrinsic properties of Layer 5 neurons, to determine their time course and to evaluate the role of glutamate receptors in their generation. Coronal slices of mouse somatosensory cortex were maintained at 36°C in an interface chamber and challenged with episodes of hypoxia. In recordings with cell-attached electrodes, the open probability of Ca(2+)-dependent BK channels began to increase within seconds of hypoxia onset, indicating a sharp rise in [Ca(2+)]i just beneath the membrane. By using a high concentration of K(+) in the pipette, we simultaneously monitored the membrane potential and showed that the [Ca(2+)]i rise was not associated with membrane depolarization. The earliest hypoxia-induced synaptic disturbance was a marked increase in the frequency of sPSCs, which also began soon after the removal of oxygen and long before AD. This synaptic effect was accompanied by depletion of the readily releasable transmitter pools, as demonstrated by a decreased response to hyperosmotic solutions. The early [Ca(2+)]i rise, the early increase in transmitter release and the subsequent AD itself were all prevented by bathing in a cocktail containing blockers of ionotropic glutamate receptors. We found no evidence for involvement of pannexin hemichannels or TRPM7 channels in the early responses to hypoxia in this experimental preparation. Our data indicate that the earliest cellular consequences of cortical hypoxia are triggered by activation of glutamate-gated channels.
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Chloride Cotransporters as a Molecular Mechanism underlying Spreading Depolarization-Induced Dendritic Beading. J Neurosci 2015; 35:12172-87. [PMID: 26338328 DOI: 10.1523/jneurosci.0400-15.2015] [Citation(s) in RCA: 64] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
UNLABELLED Spreading depolarizations (SDs) are waves of sustained neuronal and glial depolarization that propagate massive disruptions of ion gradients through the brain. SD is associated with migraine aura and recently recognized as a novel mechanism of injury in stroke and brain trauma patients. SD leads to neuronal swelling as assessed in real time with two-photon laser scanning microscopy (2PLSM). Pyramidal neurons do not express aquaporins and thus display low inherent water permeability, yet SD rapidly induces focal swelling (beading) along the dendritic shaft by unidentified molecular mechanisms. To address this issue, we induced SD in murine hippocampal slices by focal KCl microinjection and visualized the ensuing beading of dendrites expressing EGFP by 2PLSM. We confirmed that dendritic beading failed to arise during large (100 mOsm) hyposmotic challenges, underscoring that neuronal swelling does not occur as a simple osmotic event. SD-induced dendritic beading was not prevented by pharmacological interference with the cytoskeleton, supporting the notion that dendritic beading may result entirely from excessive water influx. Dendritic beading was strictly dependent on the presence of Cl(-), and, accordingly, combined blockade of Cl(-)-coupled transporters led to a significant reduction in dendritic beading without interfering with SD. Furthermore, our in vivo data showed a strong inhibition of dendritic beading during pharmacological blockage of these cotransporters. We propose that SD-induced dendritic beading takes place as a consequence of the altered driving forces and thus activity for these cotransporters, which by transport of water during their translocation mechanism may generate dendritic beading independently of osmotic forces. SIGNIFICANCE STATEMENT Spreading depolarization occurs during pathological conditions such as stroke, brain injury, and migraine and is characterized as a wave of massive ion translocation between intracellular and extracellular space in association with recurrent transient focal swelling (beading) of dendrites. Numerous ion channels have been demonstrated to be involved in generation and propagation of spreading depolarization, but the molecular machinery responsible for the dendritic beading has remained elusive. Using real-time in vitro and in vivo two-photon laser scanning microscopy, we have identified the transport mechanisms involved in the detrimental focal swelling of dendrites. These findings have clear clinical significance because they may point to a new class of pharmacological targets for prevention of neuronal swelling that consequently will serve as neuroprotective agents.
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Kahle KT, Khanna AR, Alper SL, Adragna NC, Lauf PK, Sun D, Delpire E. K-Cl cotransporters, cell volume homeostasis, and neurological disease. Trends Mol Med 2015; 21:513-23. [PMID: 26142773 PMCID: PMC4834970 DOI: 10.1016/j.molmed.2015.05.008] [Citation(s) in RCA: 87] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2015] [Revised: 05/10/2015] [Accepted: 05/29/2015] [Indexed: 11/24/2022]
Abstract
K(+)-Cl(-) cotransporters (KCCs) were originally characterized as regulators of red blood cell (RBC) volume. Since then, four distinct KCCs have been cloned, and their importance for volume regulation has been demonstrated in other cell types. Genetic models of certain KCCs, such as KCC3, and their inhibitory WNK-STE20/SPS1-related proline/alanine-rich kinase (SPAK) serine-threonine kinases, have demonstrated the evolutionary necessity of these molecules for nervous system cell volume regulation, structure, and function, and their involvement in neurological disease. The recent characterization of a swelling-activated dephosphorylation mechanism that potently stimulates the KCCs has pinpointed a potentially druggable switch of KCC activity. An improved understanding of WNK/SPAK-mediated KCC cell volume regulation in the nervous system might reveal novel avenues for the treatment of multiple neurological diseases.
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Affiliation(s)
- Kristopher T Kahle
- Department of Neurosurgery, Boston Children's Hospital and Harvard Medical School, Boston, MA 02114, USA; Manton Center for Orphan Disease Research, Children's Hospital Boston, 300 Longwood Avenue, Boston, MA 02114, USA.
| | - Arjun R Khanna
- Department of Neurosurgery, Boston Children's Hospital and Harvard Medical School, Boston, MA 02114, USA
| | - Seth L Alper
- Renal Division and Molecular and Vascular Medicine Division, Beth Israel Deaconess Medical Center; Department of Medicine, Harvard Medical School, Boston, MA 02215, USA
| | - Norma C Adragna
- Department of Pharmacology and Toxicology, Boonshoft School of Medicine, Wright State University, Dayton, OH 45435, USA
| | - Peter K Lauf
- Department of Pharmacology and Toxicology, Boonshoft School of Medicine, Wright State University, Dayton, OH 45435, USA; Department of Pathology, Boonshoft School of Medicine, Wright State University, Dayton, OH 45435, USA
| | - Dandan Sun
- Department of Neurology, University of Pittsburgh, Pittsburgh, PA 15217, USA; Veterans Affairs Pittsburgh Health Care System, Geriatric Research, Educational and Clinical Center, Pittsburgh, PA 15213, USA
| | - Eric Delpire
- Department of Anesthesiology, Vanderbilt University School of Medicine, Nashville, TN 37232, USA.
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Jonz MG, Buck LT, Perry SF, Schwerte T, Zaccone G. Sensing and surviving hypoxia in vertebrates. Ann N Y Acad Sci 2015; 1365:43-58. [PMID: 25959851 DOI: 10.1111/nyas.12780] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2015] [Revised: 03/26/2015] [Accepted: 03/31/2015] [Indexed: 12/15/2022]
Abstract
Surviving hypoxia is one of the most critical challenges faced by vertebrates. Most species have adapted to changing levels of oxygen in their environment with specialized organs that sense hypoxia, while only few have been uniquely adapted to survive prolonged periods of anoxia. The goal of this review is to present the most recent research on oxygen sensing, adaptation to hypoxia, and mechanisms of anoxia tolerance in nonmammalian vertebrates. We discuss the respiratory structures in fish, including the skin, gills, and air-breathing organs, and recent evidence for chemosensory neuroepithelial cells (NECs) in these tissues that initiate reflex responses to hypoxia. The use of the zebrafish as a genetic and developmental model has allowed observation of the ontogenesis of respiratory and chemosensory systems, demonstration of a putative intracellular O2 sensor in chemoreceptors that may initiate transduction of the hypoxia signal, and investigation into the effects of extreme hypoxia on cardiorespiratory development. Other organisms, such as goldfish and freshwater turtles, display a high degree of anoxia tolerance, and these models are revealing important adaptations at the cellular level, such as the regulation of glutamatergic and GABAergic neurotransmission in defense of homeostasis in central neurons.
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Affiliation(s)
- Michael G Jonz
- Department of Biology, University of Ottawa, Ottawa, Ontario, Canada
| | - Leslie T Buck
- Cell and Systems Biology, and Ecology and Evolutionary Biology, University of Toronto, Toronto, Ontario, Canada
| | - Steve F Perry
- Department of Biology, University of Ottawa, Ottawa, Ontario, Canada
| | | | - Giacomo Zaccone
- Department of Environmental Sciences, Territorial, Food and Health Security (S.A.S.T.A.S.), University of Messina, Messina, Italy
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Goddeyne C, Nichols J, Wu C, Anderson T. Repetitive mild traumatic brain injury induces ventriculomegaly and cortical thinning in juvenile rats. J Neurophysiol 2015; 113:3268-80. [PMID: 25695652 DOI: 10.1152/jn.00970.2014] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2014] [Accepted: 02/13/2015] [Indexed: 11/22/2022] Open
Abstract
Traumatic brain injury (TBI) most frequently occurs in pediatric patients and remains a leading cause of childhood death and disability. Mild TBI (mTBI) accounts for nearly 75% of all TBI cases, yet its neuropathophysiology is still poorly understood. While even a single mTBI injury can lead to persistent deficits, repeat injuries increase the severity and duration of both acute symptoms and long-term deficits. In this study, to model pediatric repetitive mTBI (rmTBI) we subjected unrestrained juvenile animals (postnatal day 20) to repeat weight-drop impacts. Animals were anesthetized and subjected to sham injury or rmTBI once per day for 5 days. Magnetic resonance imaging (MRI) performed 14 days after injury revealed marked cortical atrophy and ventriculomegaly in rmTBI animals. Specifically, beneath the impact zone the thickness of the cortex was reduced by up to 46% and the area of the ventricles increased by up to 970%. Immunostaining with the neuron-specific marker NeuN revealed an overall loss of neurons within the motor cortex but no change in neuronal density. Examination of intrinsic and synaptic properties of layer II/III pyramidal neurons revealed no significant difference between sham-injured and rmTBI animals at rest or under convulsant challenge with the potassium channel blocker 4-aminopyridine. Overall, our findings indicate that the neuropathological changes reported after pediatric rmTBI can be effectively modeled by repeat weight drop in juvenile animals. Developing a better understanding of how rmTBI alters the pediatric brain may help improve patient care and direct "return to game" decision making in adolescents.
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Affiliation(s)
- Corey Goddeyne
- University of Arizona, College of Medicine-Phoenix, Phoenix, Arizona; and School of Life Sciences, Arizona State University, Tempe, Arizona
| | - Joshua Nichols
- University of Arizona, College of Medicine-Phoenix, Phoenix, Arizona; and School of Life Sciences, Arizona State University, Tempe, Arizona
| | - Chen Wu
- University of Arizona, College of Medicine-Phoenix, Phoenix, Arizona; and
| | - Trent Anderson
- University of Arizona, College of Medicine-Phoenix, Phoenix, Arizona; and
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25
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Prolonged deficits in parvalbumin neuron stimulation-evoked network activity despite recovery of dendritic structure and excitability in the somatosensory cortex following global ischemia in mice. J Neurosci 2015; 34:14890-900. [PMID: 25378156 DOI: 10.1523/jneurosci.1775-14.2014] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Relatively few studies have examined plasticity of inhibitory neuronal networks following stroke in vivo, primarily due to the inability to selectively monitor inhibition. We assessed the structure of parvalbumin (PV) interneurons during a 5 min period of global ischemia and reperfusion in mice, which mimicked cerebral ischemia during cardiac arrest or forms of transient ischemic attack. The dendritic structure of PV-neurons in cortical superficial layers was rapidly swollen and beaded during global ischemia, but recovered within 5-10 min following reperfusion. Using optogenetics and a multichannel optrode, we investigated the function of PV-neurons in mouse forelimb somatosensory cortex. We demonstrated pharmacologically that PV-channelrhodopsin-2 (ChR2) stimulation evoked activation in layer IV/V, which resulted in rapid current sinks mediated by photocurrent and action potentials (a measure of PV-neuron excitability), which was then followed by current sources mediated by network GABAergic synaptic activity. During ischemic depolarization, the PV-ChR2-evoked current sinks (excitability) were suppressed, but recovered rapidly following reperfusion concurrent with repolarization of the DC-EEG. In contrast, the current sources reflecting GABAergic synaptic network activity recovered slowly and incompletely, and was coincident with the partial recovery of the forepaw stimulation-evoked current sinks in layer IV/V 30 min post reperfusion. Our in vivo data suggest that the excitability of PV inhibitory neurons was suppressed during global ischemia and rapidly recovered during reperfusion. In contrast, PV-ChR2 stimulation-evoked GABAergic synaptic network activity exhibited a prolonged suppression even ∼1 h after reperfusion, which could contribute to the dysfunction of sensation and cognition following transient global ischemia.
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26
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Neumann JT, Thompson JW, Raval AP, Cohan CH, Koronowski KB, Perez-Pinzon MA. Increased BDNF protein expression after ischemic or PKC epsilon preconditioning promotes electrophysiologic changes that lead to neuroprotection. J Cereb Blood Flow Metab 2015; 35:121-30. [PMID: 25370861 PMCID: PMC4294405 DOI: 10.1038/jcbfm.2014.185] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/18/2014] [Revised: 10/02/2014] [Accepted: 10/03/2014] [Indexed: 01/06/2023]
Abstract
Ischemic preconditioning (IPC) via protein kinase C epsilon (PKCɛ) activation induces neuroprotection against lethal ischemia. Brain-derived neurotrophic factor (BDNF) is a pro-survival signaling molecule that modulates synaptic plasticity and neurogenesis. Interestingly, BDNF mRNA expression increases after IPC. In this study, we investigated whether IPC or pharmacological preconditioning (PKCɛ activation) promoted BDNF-induced neuroprotection, if neuroprotection by IPC or PKCɛ activation altered neuronal excitability, and whether these changes were BDNF-mediated. We used both in vitro (hippocampal organotypic cultures and cortical neuronal-glial cocultures) and in vivo (acute hippocampal slices 48 hours after preconditioning) models of IPC or PKCɛ activation. BDNF protein expression increased 24 to 48 hours after preconditioning, where inhibition of the BDNF Trk receptors abolished neuroprotection against oxygen and glucose deprivation (OGD) in vitro. In addition, there was a significant decrease in neuronal firing frequency and increase in threshold potential 48 hours after preconditioning in vivo, where this threshold modulation was dependent on BDNF activation of Trk receptors in excitatory cortical neurons. In addition, 48 hours after PKCɛ activation in vivo, the onset of anoxic depolarization during OGD was significantly delayed in hippocampal slices. Overall, these results suggest that after IPC or PKCɛ activation, there are BDNF-dependent electrophysiologic modifications that lead to neuroprotection.
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Affiliation(s)
- Jake T Neumann
- 1] Cerebral Vascular Disease Research Laboratories, University of Miami Leonard M. Miller School of Medicine, Miami, Florida, USA [2] Evelyn F. McKnight Brain Institute, University of Miami Leonard M. Miller School of Medicine, Miami, Florida, USA [3] Department of Neurology, University of Miami Leonard M. Miller School of Medicine, Miami, Florida, USA
| | - John W Thompson
- 1] Cerebral Vascular Disease Research Laboratories, University of Miami Leonard M. Miller School of Medicine, Miami, Florida, USA [2] Department of Neurology, University of Miami Leonard M. Miller School of Medicine, Miami, Florida, USA
| | - Ami P Raval
- 1] Cerebral Vascular Disease Research Laboratories, University of Miami Leonard M. Miller School of Medicine, Miami, Florida, USA [2] Evelyn F. McKnight Brain Institute, University of Miami Leonard M. Miller School of Medicine, Miami, Florida, USA [3] Department of Neurology, University of Miami Leonard M. Miller School of Medicine, Miami, Florida, USA
| | - Charles H Cohan
- 1] Cerebral Vascular Disease Research Laboratories, University of Miami Leonard M. Miller School of Medicine, Miami, Florida, USA [2] Evelyn F. McKnight Brain Institute, University of Miami Leonard M. Miller School of Medicine, Miami, Florida, USA [3] Department of Neurology, University of Miami Leonard M. Miller School of Medicine, Miami, Florida, USA [4] Neuroscience Program, University of Miami Leonard M. Miller School of Medicine, Miami, Florida, USA
| | - Kevin B Koronowski
- 1] Cerebral Vascular Disease Research Laboratories, University of Miami Leonard M. Miller School of Medicine, Miami, Florida, USA [2] Department of Neurology, University of Miami Leonard M. Miller School of Medicine, Miami, Florida, USA [3] Neuroscience Program, University of Miami Leonard M. Miller School of Medicine, Miami, Florida, USA
| | - Miguel A Perez-Pinzon
- 1] Cerebral Vascular Disease Research Laboratories, University of Miami Leonard M. Miller School of Medicine, Miami, Florida, USA [2] Evelyn F. McKnight Brain Institute, University of Miami Leonard M. Miller School of Medicine, Miami, Florida, USA [3] Department of Neurology, University of Miami Leonard M. Miller School of Medicine, Miami, Florida, USA [4] Neuroscience Program, University of Miami Leonard M. Miller School of Medicine, Miami, Florida, USA
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Larson J, Drew KL, Folkow LP, Milton SL, Park TJ. No oxygen? No problem! Intrinsic brain tolerance to hypoxia in vertebrates. ACTA ACUST UNITED AC 2014; 217:1024-39. [PMID: 24671961 DOI: 10.1242/jeb.085381] [Citation(s) in RCA: 108] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Many vertebrates are challenged by either chronic or acute episodes of low oxygen availability in their natural environments. Brain function is especially vulnerable to the effects of hypoxia and can be irreversibly impaired by even brief periods of low oxygen supply. This review describes recent research on physiological mechanisms that have evolved in certain vertebrate species to cope with brain hypoxia. Four model systems are considered: freshwater turtles that can survive for months trapped in frozen-over lakes, arctic ground squirrels that respire at extremely low rates during winter hibernation, seals and whales that undertake breath-hold dives lasting minutes to hours, and naked mole-rats that live in crowded burrows completely underground for their entire lives. These species exhibit remarkable specializations of brain physiology that adapt them for acute or chronic episodes of hypoxia. These specializations may be reactive in nature, involving modifications to the catastrophic sequelae of oxygen deprivation that occur in non-tolerant species, or preparatory in nature, preventing the activation of those sequelae altogether. Better understanding of the mechanisms used by these hypoxia-tolerant vertebrates will increase appreciation of how nervous systems are adapted for life in specific ecological niches as well as inform advances in therapy for neurological conditions such as stroke and epilepsy.
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Affiliation(s)
- John Larson
- Psychiatric Institute, Department of Psychiatry and Laboratory of Integrative Neuroscience, Department of Biological Sciences, University of Illinois, Chicago, IL 60612, USA
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28
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Nichols J, Perez R, Wu C, Adelson PD, Anderson T. Traumatic brain injury induces rapid enhancement of cortical excitability in juvenile rats. CNS Neurosci Ther 2014; 21:193-203. [PMID: 25475223 DOI: 10.1111/cns.12351] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2014] [Revised: 10/15/2014] [Accepted: 10/20/2014] [Indexed: 11/29/2022] Open
Abstract
AIMS Following a traumatic brain injury (TBI), 5-50% of patients will develop posttraumatic epilepsy (PTE) with children being particularly susceptible. Currently, PTE cannot be prevented and there is limited understanding of the underlying epileptogenic mechanisms. We hypothesize that early after TBI the brain undergoes distinct cellular and synaptic reorganization that facilitates cortical excitability and promotes the development of epilepsy. METHODS To examine the effect of pediatric TBI on cortical excitability, we performed controlled cortical impact (CCI) on juvenile rats (postnatal day 17). Following CCI, animals were monitored for the presence of epileptiform activity by continuous in vivo electroencephalography (EEG) and/or sacrificed for in vitro whole-cell patch-clamp recordings. RESULTS Following a short latent period, all animals subjected to CCI developed spontaneous recurrent epileptiform activity within 14 days. Whole-cell patch-clamp recordings of layer V pyramidal neurons showed no changes in intrinsic excitability or spontaneous excitatory postsynaptic currents (sEPSCs) properties. However, the decay of spontaneous inhibitory postsynaptic currents (sIPSCs) was significantly increased. In addition, CCI induced over a 300% increase in excitatory and inhibitory synaptic bursting. Synaptic bursting was prevented by blockade of Na(+)-dependent action potentials or select antagonism of glutamate or GABA-A receptors, respectively. CONCLUSION Our results demonstrate that CCI in juvenile rats rapidly induces epileptiform activity and enhanced cortical synaptic bursting. Detection of epileptiform activity early after injury suggests it may be an important pathophysiological component and potential indicator of developing PTE.
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Affiliation(s)
- Joshua Nichols
- University of Arizona, College of Medicine - Phoenix, Phoenix, AZ, USA; School of Life Sciences, Arizona State University, Phoenix, AZ, USA
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29
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Reactive oxygen species initiate a metabolic collapse in hippocampal slices: potential trigger of cortical spreading depression. J Cereb Blood Flow Metab 2014; 34:1540-9. [PMID: 25027308 PMCID: PMC4158675 DOI: 10.1038/jcbfm.2014.121] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/05/2014] [Revised: 05/27/2014] [Accepted: 06/16/2014] [Indexed: 11/08/2022]
Abstract
Excessive accumulation of reactive oxygen species (ROS) underlies oxidative damage. We find that in hippocampal slices, decreased activity of glucose-based antioxidant system induces a massive, abrupt, and detrimental change in cellular functions. We call this phenomenon metabolic collapse (MC). This collapse manifested in long-lasting silencing of synaptic transmission, abnormal oxidation of NAD(P)H and FADH2 associated with immense oxygen consumption, and massive neuronal depolarization. MC occurred without any preceding deficiency in neuronal energy supply or disturbances of ionic homeostasis and spread throughout the hippocampus. It was associated with a preceding accumulation of ROS and was largely prevented by application of an efficient antioxidant Tempol (4-hydroxy-2,2,6,6-tetramethylpiperidine-1-oxyl). The consequences of MC resemble cortical spreading depression (CSD), a wave of neuronal depolarization that occurs in migraine, brain trauma, and stroke, the cellular initiation mechanisms of which are poorly understood. We suggest that ROS accumulation might also be the primary trigger of CSD. Indeed, we found that Tempol strongly reduced occurrence of CSD in vivo, suggesting that ROS accumulation may be a key mechanism of CSD initiation.
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30
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Pietrobon D, Moskowitz MA. Chaos and commotion in the wake of cortical spreading depression and spreading depolarizations. Nat Rev Neurosci 2014; 15:379-93. [PMID: 24857965 DOI: 10.1038/nrn3770] [Citation(s) in RCA: 266] [Impact Index Per Article: 26.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Punctuated episodes of spreading depolarizations erupt in the brain, encumbering tissue structure and function, and raising fascinating unanswered questions concerning their initiation and propagation. Linked to migraine aura and headache, cortical spreading depression contributes to the morbidity in the world's migraine with aura population. Even more ominously, erupting spreading depolarizations accelerate tissue damage during brain injury. The once-held view that spreading depolarizations may not exist in the human brain has changed, largely because of the discovery of migraine genes that confer cortical spreading depression susceptibility, the application of sophisticated imaging tools and efforts to interrogate their impact in the acutely injured human brain.
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Affiliation(s)
- Daniela Pietrobon
- Department of Biomedical Sciences and CNR Institute of Neuroscience, University of Padova 35121 Padova, Italy
| | - Michael A Moskowitz
- 1] Stroke and Neurovascular Regulation Laboratory, Departments of Radiology and Neurology, 149 13th Street, Room 6403, Massachusetts General Hospital, Charlestown, Massachusetts 02129, USA. [2] Department of Neurology, Harvard Medical School, Boston, Massachusetts, USA
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Abstract
Decreased oxygen availability impairs cellular energy production and, without a coordinated and matched decrease in energy consumption, cellular and whole organism death rapidly ensues. Of particular interest are mechanisms that protect brain from low oxygen injury, as this organ is not only the most sensitive to hypoxia, but must also remain active and functional during low oxygen stress. As a result of natural selective pressures, some species have evolved molecular and physiological mechanisms to tolerate prolonged hypoxia with no apparent detriment. Among these mechanisms are a handful of responses that are essential for hypoxia tolerance, including (i) sensors that detect changes in oxygen availability and initiate protective responses; (ii) mechanisms of energy conservation; (iii) maintenance of basic brain function; and (iv) avoidance of catastrophic cell death cascades. As the study of hypoxia-tolerant brain progresses, it is becoming increasingly apparent that mitochondria play a central role in regulating all of these critical mechanisms. Furthermore, modulation of mitochondrial function to mimic endogenous neuroprotective mechanisms found in hypoxia-tolerant species confers protection against otherwise lethal hypoxic stresses in hypoxia-intolerant organs and organisms. Therefore, lessons gleaned from the investigation of endogenous mechanisms of hypoxia tolerance in hypoxia-tolerant organisms may provide insight into clinical pathologies related to low oxygen stress.
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Affiliation(s)
- Matthew E. Pamenter
- Department of Zoology, The University of British Columbia, #4200-6270 University Boulevard, Vancouver, BC V6T 1Z4, Canada
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32
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Brisson CD, Hsieh YT, Kim D, Jin AY, Andrew RD. Brainstem neurons survive the identical ischemic stress that kills higher neurons: insight to the persistent vegetative state. PLoS One 2014; 9:e96585. [PMID: 24802253 PMCID: PMC4011844 DOI: 10.1371/journal.pone.0096585] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2014] [Accepted: 04/08/2014] [Indexed: 11/19/2022] Open
Abstract
Global ischemia caused by heart attack, pulmonary failure, near-drowning or traumatic brain injury often damages the higher brain but not the brainstem, leading to a ‘persistent vegetative state’ where the patient is awake but not aware. Approximately 30,000 U.S. patients are held captive in this condition but not a single research study has addressed how the lower brain is preferentially protected in these people. In the higher brain, ischemia elicits a profound anoxic depolarization (AD) causing neuronal dysfunction and vasoconstriction within minutes. Might brainstem nuclei generate less damaging AD and so be more resilient? Here we compared resistance to acute injury induced from simulated ischemia by ‘higher’ hippocampal and striatal neurons versus brainstem neurons in live slices from rat and mouse. Light transmittance (LT) imaging in response to 10 minutes of oxygen/glucose deprivation (OGD) revealed immediate and acutely damaging AD propagating through gray matter of neocortex, hippocampus, striatum, thalamus and cerebellar cortex. In adjacent brainstem nuclei, OGD-evoked AD caused little tissue injury. Whole-cell patch recordings from hippocampal and striatal neurons under OGD revealed sudden membrane potential loss that did not recover. In contrast brainstem neurons from locus ceruleus and mesencephalic nucleus as well as from sensory and motor nuclei only slowly depolarized and then repolarized post-OGD. Two-photon microscopy confirmed non-recoverable swelling and dendritic beading of hippocampal neurons during OGD, while mesencephalic neurons in midbrain appeared uninjured. All of the above responses were mimicked by bath exposure to 100 µM ouabain which inhibits the Na+/K+ pump or to 1–10 nM palytoxin which converts the pump into an open cationic channel. Therefore during ischemia the Na+/K+ pump of higher neurons fails quickly and extensively compared to naturally resilient hypothalamic and brainstem neurons. The selective survival of lower brain regions that maintain vital functions will support the persistent vegetative state.
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Affiliation(s)
- C. Devin Brisson
- Department of Biomedical & Molecular Sciences, Queen's University, Kingston, Ontario, Canada
| | - Yi-Ting Hsieh
- Department of Biomedical & Molecular Sciences, Queen's University, Kingston, Ontario, Canada
| | - Danielle Kim
- Department of Biomedical & Molecular Sciences, Queen's University, Kingston, Ontario, Canada
| | - Albert Y. Jin
- Department of Biomedical & Molecular Sciences, Queen's University, Kingston, Ontario, Canada
| | - R. David Andrew
- Department of Biomedical & Molecular Sciences, Queen's University, Kingston, Ontario, Canada
- * E-mail:
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Ahlgren H, Bas-Orth C, Freitag HE, Hellwig A, Ottersen OP, Bading H. The nuclear calcium signaling target, activating transcription factor 3 (ATF3), protects against dendrotoxicity and facilitates the recovery of synaptic transmission after an excitotoxic insult. J Biol Chem 2014; 289:9970-82. [PMID: 24515113 DOI: 10.1074/jbc.m113.502914] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The focal swellings of dendrites ("dendritic beading") are an early morphological hallmark of neuronal injury and dendrotoxicity. They are associated with a variety of pathological conditions, including brain ischemia, and cause an acute disruption of synaptic transmission and neuronal network function, which contribute to subsequent neuronal death. Here, we show that increased synaptic activity prior to excitotoxic injury protects, in a transcription-dependent manner, against dendritic beading. Expression of activating transcription factor 3 (ATF3), a nuclear calcium-regulated gene and member of the core gene program for acquired neuroprotection, can protect against dendritic beading. Conversely, knockdown of ATF3 exacerbates dendritic beading. Assessment of neuronal network functions using microelectrode array recordings revealed that hippocampal neurons expressing ATF3 were able to regain their ability for functional synaptic transmission and to participate in coherent neuronal network activity within 48 h after exposure to toxic concentrations of NMDA. Thus, in addition to attenuating cell death, synaptic activity and expression of ATF3 render hippocampal neurons more resistant to acute dendrotoxicity and loss of synapses. Dendroprotection can enhance recovery of neuronal network functions after excitotoxic insults.
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Affiliation(s)
- Hanna Ahlgren
- From the Department of Neurobiology, Interdisciplinary Center for Neurosciences, University of Heidelberg, INF 364, 69120 Heidelberg, Germany and
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Xiong XX, Gu LJ, Shen J, Kang XH, Zheng YY, Yue SB, Zhu SM. Probenecid protects against transient focal cerebral ischemic injury by inhibiting HMGB1 release and attenuating AQP4 expression in mice. Neurochem Res 2013; 39:216-24. [PMID: 24317635 DOI: 10.1007/s11064-013-1212-z] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2013] [Revised: 10/31/2013] [Accepted: 11/25/2013] [Indexed: 12/11/2022]
Abstract
Stroke results in inflammation, brain edema, and neuronal death. However, effective neuroprotectants are not available. Recent studies have shown that high mobility group box-1 (HMGB1), a proinflammatory cytokine, contributes to ischemic brain injury. Aquaporin 4 (AQP4), a water channel protein, is considered to play a pivotal role in ischemia-induced brain edema. More recently, studies have shown that pannexin 1 channels are involved in cerebral ischemic injury and the cellular inflammatory response. Here, we examined whether the pannexin 1 channel inhibitor probenecid could reduce focal ischemic brain injury by inhibiting cerebral inflammation and edema. Transient focal ischemia was induced in C57BL/6J mice by middle cerebral artery occlusion (MCAO) for 1 h. Infarct volume, neurological score and cerebral water content were evaluated 48 h after MCAO. Immunostaining, western blot analysis and ELISA were used to assess the effects of probenecid on the cellular inflammatory response, HMGB1 release and AQP4 expression. Administration of probenecid reduced infarct size, decreased cerebral water content, inhibited neuronal death, and reduced inflammation in the brain 48 h after stroke. In addition, HMGB1 release from neurons was significantly diminished and serum HMGB1 levels were substantially reduced following probenecid treatment. Moreover, AQP4 protein expression was downregulated in the cortical penumbra following post-stroke treatment with probenecid. These results suggest that probenecid, a powerful pannexin 1 channel inhibitor, protects against ischemic brain injury by inhibiting cerebral inflammation and edema.
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Affiliation(s)
- Xiao-Xing Xiong
- Department of Anesthesia, the First Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, Zhejiang, China
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Brisson CD, Lukewich MK, Andrew RD. A distinct boundary between the higher brain's susceptibility to ischemia and the lower brain's resistance. PLoS One 2013; 8:e79589. [PMID: 24223181 PMCID: PMC3819273 DOI: 10.1371/journal.pone.0079589] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2013] [Accepted: 10/03/2013] [Indexed: 11/19/2022] Open
Abstract
Higher brain regions are more susceptible to global ischemia than the brainstem, but is there a gradual increase in vulnerability in the caudal-rostral direction or is there a discrete boundary? We examined the interface between `higher` thalamus and the hypothalamus the using live brain slices where variation in blood flow is not a factor. Whole-cell current clamp recording of 18 thalamic neurons in response to 10 min O2/glucose deprivation (OGD) revealed a rapid anoxic depolarization (AD) from which thalamic neurons do not recover. Newly acquired neurons could not be patched following AD, confirming significant regional thalamic injury. Coinciding with AD, light transmittance (LT) imaging during whole-cell recording showed an elevated LT front that initiated in midline thalamus and that propagated into adjacent hypothalamus. However, hypothalamic neurons patched in paraventricular nucleus (PVN, n= 8 magnocellular and 12 parvocellular neurons) and suprachiasmatic nucleus (SCN, n= 18) only slowly depolarized as AD passed through these regions. And with return to control aCSF, hypothalamic neurons repolarized and recovered their input resistance and action potential amplitude. Moreover, newly acquired hypothalamic neurons could be readily patched following exposure to OGD, with resting parameters similar to neurons not previously exposed to OGD. Thalamic susceptibility and hypothalamic resilience were also observed following ouabain exposure which blocks the Na+/K+ pump, evoking depolarization similar to OGD in all neuronal types tested. Finally, brief exposure to elevated [K+]o caused spreading depression (SD, a milder, AD-like event) only in thalamic neurons so SD generation is regionally correlated with strong AD. Therefore the thalamus-hypothalamus interface represents a discrete boundary where neuronal vulnerability to ischemia is high in thalamus (like more rostral neocortex, striatum, hippocampus). In contrast hypothalamic neurons are comparatively resistant, generating weaker and recoverable anoxic depolarization similar to brainstem neurons, possibly the result of a Na/K pump that better functions during ischemia.
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Affiliation(s)
- C. Devin Brisson
- Department of Biomedical and Molecular Sciences, Queen’s University, Kingston, Ontario, Canada
| | - Mark K. Lukewich
- Department of Biomedical and Molecular Sciences, Queen’s University, Kingston, Ontario, Canada
| | - R. David Andrew
- Department of Biomedical and Molecular Sciences, Queen’s University, Kingston, Ontario, Canada
- * E-mail:
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Dave KR, Christian SL, Perez-Pinzon MA, Drew KL. Neuroprotection: lessons from hibernators. Comp Biochem Physiol B Biochem Mol Biol 2012; 162:1-9. [PMID: 22326449 PMCID: PMC3334476 DOI: 10.1016/j.cbpb.2012.01.008] [Citation(s) in RCA: 82] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2011] [Revised: 01/26/2012] [Accepted: 01/30/2012] [Indexed: 12/15/2022]
Abstract
Mammals that hibernate experience extreme metabolic states and body temperatures as they transition between euthermia, a state resembling typical warm blooded mammals, and prolonged torpor, a state of suspended animation where the brain receives as low as 10% of normal cerebral blood flow. Transitions into and out of torpor are more physiologically challenging than the extreme metabolic suppression and cold body temperatures of torpor per se. Mammals that hibernate show unprecedented capacities to tolerate cerebral ischemia, a decrease in blood flow to the brain caused by stroke, cardiac arrest or brain trauma. While cerebral ischemia often leads to death or disability in humans and most other mammals, hibernating mammals suffer no ill effects when blood flow to the brain is dramatically decreased during torpor or experimentally induced during euthermia. These animals, as adults, also display rapid and pronounced synaptic flexibility where synapses retract during torpor and rapidly re-emerge upon arousal. A variety of coordinated adaptations contribute to tolerance of cerebral ischemia in these animals. In this review we discuss adaptations in heterothermic mammals that may suggest novel therapeutic targets and strategies to protect the human brain against cerebral ischemic damage and neurodegenerative disease.
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Affiliation(s)
- Kunjan R Dave
- Cerebral Vascular Disease Research Laboratories, Department of Neurology, Leonard M. Miller School of Medicine, University of Miami, Miami, FL 33136, USA.
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Brisson CD, Andrew RD. A neuronal population in hypothalamus that dramatically resists acute ischemic injury compared to neocortex. J Neurophysiol 2012; 108:419-30. [PMID: 22514289 DOI: 10.1152/jn.00090.2012] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Pyramidal neurons (PyNs) of the cortex are highly susceptible to acute stroke damage, yet "lower" brain regions like hypothalamus and brain stem better survive global ischemia. Here we show for the first time that a "lower" neuron population intrinsically resists acute strokelike injury. In rat brain slices deprived of oxygen and glucose (OGD), we imaged anoxic depolarization (AD) as it propagated through neocortex or hypothalamus. AD, the initial electrophysiological event of stroke, is a front of depolarization that drains residual energy in compromised gray matter. The extent of AD reliably determines ensuing cortical damage, but do all CNS neurons generate a robust AD? During 10 min of OGD, PyNs depolarize without functional recovery. In contrast, magnocellular neuroendocrine cells (MNCs) in hypothalamus under identical stress generate a weak and delayed AD, resist complete depolarization, and rapidly repolarize when oxygen and glucose are restored. They recover their membrane potential, input resistance, and spike amplitude and can survive multiple OGD exposures. Two-photon microscopy in slices derived from a fluorescent mouse line confirms this protection, revealing PyN swelling and dendritic beading after OGD, whereas MNCs are not injured. Exposure to the Na(+)-K(+)-ATPase inhibitor ouabain (100 μM) induces AD similar to OGD in both cell types. Moreover, elevated extracellular K(+) concentration ([K(+)](o)) evokes spreading depression (SD), a milder version of AD, in PyNs but not MNCs. Therefore overriding the pump by OGD, ouabain, or elevated [K(+)](o) evokes a propagating depolarization in higher gray matter but not in MNCs. We suggest that variation in Na(+)-K(+)-ATPase pump efficiency during ischemia injury determines whether a neuronal type succumbs to or resists stroke.
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Affiliation(s)
- C Devin Brisson
- Department of Biomedical and Molecular Sciences, Queen's University, Kingston, Ontario, Canada
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White SH, Brisson CD, Andrew RD. Examining protection from anoxic depolarization by the drugs dibucaine and carbetapentane using whole cell recording from CA1 neurons. J Neurophysiol 2012; 107:2083-95. [PMID: 22279188 DOI: 10.1152/jn.00701.2011] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
As an immediate consequence of stroke onset, failure of the Na(+)-K(+)-ATPase pump evokes a propagating anoxic depolarization (AD) across gray matter. Acute neuronal swelling and dendritic beading arise within seconds in the future ischemic core, imaged as changes in light transmittance (ΔLT). AD is itself not a target for drug-based reduction of stroke injury because it is generated in the 1st min of stroke onset. Peri-infarct depolarizations (PIDs) are milder AD-like events that recur during the hours following AD and contribute to infarct expansion. Inhibiting PIDs with drugs could limit expansion. Two types of drugs, "caines" and σ(1)-receptor ligands, have been found to inhibit AD onset (and may also oppose PID initiation), yet their underlying actions have not been examined. Imaging ΔLT in the CA1 region simultaneously with whole cell current-clamp recording from CA1 pyramidal neurons reveal that the elevated LT front and onset of the AD are coincident. Either dibucaine or carbetapentane pretreatment significantly delays AD onset without affecting resting membrane potential or neuronal input resistance. Dibucaine decreases excitability by raising spike threshold and decreasing action potential (AP) frequency, whereas carbetapentane eliminates the fast afterhyperpolarization while accentuating the slow afterhyperpolarization to reduce AP frequency. Orthodromic and antidromic APs are eliminated by dibucaine within 15 min but not by carbetapentane. Thus both drugs reduce cortical excitability at the level of the single pyramidal neuron but through strikingly different mechanisms. In vivo, both drugs would likely inhibit recurring PIDs in the expanding penumbra and so potentially could reduce developing neuronal damage over many hours poststroke when PIDs occur.
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Affiliation(s)
- Sean H White
- Centre for Neuroscience Studies and Department of Biomedical and Molecular Sciences, Queen’s University, Kingston, Ontario, Canada
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Oxygen Sensitive Synaptic Neurotransmission in Anoxia-Tolerant Turtle Cerebrocortex. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2012; 758:71-9. [DOI: 10.1007/978-94-007-4584-1_10] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
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Risher WC, Lee MR, Fomitcheva IV, Hess DC, Kirov SA. Dibucaine mitigates spreading depolarization in human neocortical slices and prevents acute dendritic injury in the ischemic rodent neocortex. PLoS One 2011; 6:e22351. [PMID: 21789251 PMCID: PMC3137632 DOI: 10.1371/journal.pone.0022351] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2011] [Accepted: 06/20/2011] [Indexed: 12/29/2022] Open
Abstract
Background Spreading depolarizations that occur in patients with malignant stroke, subarachnoid/intracranial hemorrhage, and traumatic brain injury are known to facilitate neuronal damage in metabolically compromised brain tissue. The dramatic failure of brain ion homeostasis caused by propagating spreading depolarizations results in neuronal and astroglial swelling. In essence, swelling is the initial response and a sign of the acute neuronal injury that follows if energy deprivation is maintained. Choosing spreading depolarizations as a target for therapeutic intervention, we have used human brain slices and in vivo real-time two-photon laser scanning microscopy in the mouse neocortex to study potentially useful therapeutics against spreading depolarization-induced injury. Methodology/Principal Findings We have shown that anoxic or terminal depolarization, a spreading depolarization wave ignited in the ischemic core where neurons cannot repolarize, can be evoked in human slices from pediatric brains during simulated ischemia induced by oxygen/glucose deprivation or by exposure to ouabain. Changes in light transmittance (LT) tracked terminal depolarization in time and space. Though spreading depolarizations are notoriously difficult to block, terminal depolarization onset was delayed by dibucaine, a local amide anesthetic and sodium channel blocker. Remarkably, the occurrence of ouabain-induced terminal depolarization was delayed at a concentration of 1 µM that preserves synaptic function. Moreover, in vivo two-photon imaging in the penumbra revealed that, though spreading depolarizations did still occur, spreading depolarization-induced dendritic injury was inhibited by dibucaine administered intravenously at 2.5 mg/kg in a mouse stroke model. Conclusions/Significance Dibucaine mitigated the effects of spreading depolarization at a concentration that could be well-tolerated therapeutically. Hence, dibucaine is a promising candidate to protect the brain from ischemic injury with an approach that does not rely on the complete abolishment of spreading depolarizations.
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Affiliation(s)
- W. Christopher Risher
- Graduate Program in Neuroscience, Georgia Health Sciences University, Augusta, Georgia, United States of America
- Brain and Behavior Discovery Institute, Georgia Health Sciences University, Augusta, Georgia, United States of America
| | - Mark R. Lee
- Department of Neurosurgery, Georgia Health Sciences University, Augusta, Georgia, United States of America
| | - Ioulia V. Fomitcheva
- Department of Neurosurgery, Georgia Health Sciences University, Augusta, Georgia, United States of America
| | - David C. Hess
- Department of Neurology, Georgia Health Sciences University, Augusta, Georgia, United States of America
- Brain and Behavior Discovery Institute, Georgia Health Sciences University, Augusta, Georgia, United States of America
| | - Sergei A. Kirov
- Department of Neurosurgery, Georgia Health Sciences University, Augusta, Georgia, United States of America
- Brain and Behavior Discovery Institute, Georgia Health Sciences University, Augusta, Georgia, United States of America
- * E-mail:
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Douglas HA, Callaway JK, Sword J, Kirov SA, Andrew RD. Potent inhibition of anoxic depolarization by the sodium channel blocker dibucaine. J Neurophysiol 2011; 105:1482-94. [PMID: 21273307 DOI: 10.1152/jn.00817.2010] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Recurring waves of peri-infarct depolarizations (PIDs) propagate across gray matter in the hours and days following stroke, expanding the primary site of injury. Ischemic depolarization (termed anoxic depolarization or AD in live brain slices) is PID-like but immediately arises in the more metabolically compromised ischemic core. This causes dramatic neuronal and astrocyte swelling and dendritic beading with spine loss within minutes, resulting in acute cell death. AD is evoked in rodent neocortical slices by suppressing the Na(+)/K(+)-ATPase pump with either oxygen/glucose deprivation (OGD) or exposure to ouabain. The process driving AD and PIDs remains poorly understood. Here we show that dibucaine is a potent drug inhibiting AD because of its high binding affinity to the Na(+) channel. Field recording reveals that, when superfused with ouabain (5 min), neocortical slices pretreated with 1 μM dibucaine for 45 min display either no AD or delayed AD onset compared with untreated controls. If ouabain exposure is extended to 10 min, 1 μM dibucaine is still able to delay AD onset by ∼ 60%. Likewise, it delays OGD-evoked AD onset by ∼ 54% but does not depress action potentials (APs) or evoked orthodromic field potentials. Increasing dibucaine to 10 μM inhibits AP firing, gradually putting the slice into a stasis that inhibits AD onset but also renders the slice functionally quiescent. Two-photon microscopy reveals that 10 μM dibucaine pretreatment prevents or helps reverse ouabain-induced structural neuronal damage. Although the therapeutic range of dibucaine is quite narrow, dibucaine-like drugs could prove therapeutically useful in inhibiting PIDs and their resultant neuronal damage.
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Affiliation(s)
- Heather A Douglas
- Department of Anatomy and Cell Biology, Queen's University, Kingston, Ontario, Canada
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Nishidate I, Yoshida K, Sato M. Changes in optical properties of rat cerebral cortical slices during oxygen glucose deprivation. APPLIED OPTICS 2010; 49:6617-6623. [PMID: 21124539 DOI: 10.1364/ao.49.006617] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
We simultaneously measured the diffuse reflectance spectra and transmittance spectra of in vitro rat cerebral cortical tissue slices perfused with artificial cerebrospinal fluid (aCSF) in the wavelength range from 500 to 900 nm. An ischemia-like condition in the cortical tissue was induced by oxygen/glucose deprivation (OGD) of the aCSF. Diffuse reflectance and transmittance of the cortical slices were decreased and increased, respectively, during OGD. Spectral data of reduced scattering coefficients and absorption coefficients were estimated by the inverse Monte Carlo simulation for light transport in tissue. As with OGD, significant decrease of the reduced scattering coefficients and alteration of the absorption coefficient spectrum were observed over the measured wavelength range. The mean maximum amplitudes of change in the absorption coefficient at 520, 550, 605, and 830 nm were 0.33 ± 0.14, 0.30 ± 0.12, 0.30 ± 0.14, and -0.04 ± 0.16, respectively, whereas those in the reduced scattering coefficient at 520, 550, 605, and 830 nm were -0.37 ± 0.08, -0.38 ± 0.08, -0.38 ± 0.08, and -0.39 ± 0.08. Variations in the reduced scattering coefficients implied cell deformation mainly due to cell swelling, whereas those in the absorption spectra indicated reductions in heme aa(3) and CuA in cytochrome c oxidase and cytochrome c.
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Affiliation(s)
- Izumi Nishidate
- Graduate School of Bio-Applications and Systems Engineering, Tokyo University of Agriculture and Technology, 2-24-16, Naka-cho, Koganei, Tokyo 184-8588 Japan.
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Anderson TR, Huguenard JR, Prince DA. Differential effects of Na+-K+ ATPase blockade on cortical layer V neurons. J Physiol 2010; 588:4401-14. [PMID: 20819946 DOI: 10.1113/jphysiol.2010.191858] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Sodium-potassium ATPase ('Na(+)-K(+) ATPase') contributes to the maintenance of the resting membrane potential and the transmembrane gradients for Na(+) and K(+) in neurons. Activation of Na(+)-K(+) ATPase may be important in controlling increases in intracellular sodium during periods of increased neuronal activity. Down-regulation of Na(+)-K(+) ATPase activity is implicated in numerous CNS disorders, including epilepsy. Although Na(+)-K(+) ATPase is present in all neurons, little is known about its activity in different subclasses of neocortical cells. We assessed the physiological properties of Na(+)-K(+) ATPase in fast-spiking (FS) interneurons and pyramidal (PYR) cells to test the hypothesis that Na(+)-K(+) ATPase activity would be relatively greater in neurons that generated high frequency action potentials (the FS cells). Whole-cell patch clamp recordings were made from FS and PYR neurons in layer V of rat sensorimotor cortical slices maintained in vitro using standard techniques. Bath perfusion of Na(+)-K(+) ATPase antagonists (ouabain or dihydro-ouabain) induced either a membrane depolarization in current clamp, or inward current under voltage clamp in both cell types. PYR neurons were divided into two subpopulations based on the amplitude of the voltage or current shift in response to Na(+)-K(+) ATPase blockade. The two PYR cell groups did not differ significantly in electrophysiological properties including resting membrane potential, firing pattern, input resistance and capacitance. Membrane voltage responses of FS cells to Na(+)-K(+) ATPase blockade were intermediate between the two PYR cell groups (P < 0.05). The resting Na(+)-K(+) ATPase current density in FS interneurons, assessed by application of blockers, was 3- to 7-fold larger than in either group of PYR neurons. Na(+)-K(+) ATPase activity was increased either through direct Na(+) loading via the patch pipette or by focal application of glutamate (20 mM puffs). Under these conditions FS interneurons exhibited the largest increase in Na(+)-K(+) ATPase activity. We conclude that resting Na(+)-K(+) ATPase activity and sensitivity to changes in internal Na(+) concentration vary between and within classes of cortical neurons. These differences may have important consequences in pathophysiological disorders associated with down-regulation of Na(+)-K(+) ATPase and hyperexcitability within cortical networks.
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Affiliation(s)
- Trent R Anderson
- Neurology and Neurological Sciences, Stanford University, CA 94305, USA
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Risher WC, Ard D, Yuan J, Kirov SA. Recurrent spontaneous spreading depolarizations facilitate acute dendritic injury in the ischemic penumbra. J Neurosci 2010; 30:9859-68. [PMID: 20660268 PMCID: PMC2918261 DOI: 10.1523/jneurosci.1917-10.2010] [Citation(s) in RCA: 122] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2010] [Accepted: 06/14/2010] [Indexed: 01/22/2023] Open
Abstract
Spontaneous spreading depolarizations (SDs) occur in the penumbra surrounding ischemic core. These SDs, often referred to as peri-infarct depolarizations, cause vasoconstriction and recruitment of the penumbra into the ischemic core in the critical first hours after focal ischemic stroke; however, the real-time spatiotemporal dynamics of SD-induced injury to synaptic circuitry in the penumbra remain unknown. A modified cortical photothrombosis model was used to produce a square-shaped lesion surrounding a penumbra-like "area at risk" in middle cerebral artery territory of mouse somatosensory cortex. Lesioning resulted in recurrent spontaneous SDs. In vivo two-photon microscopy of green fluorescent protein-expressing neurons in this penumbra-like area at risk revealed that SDs were temporally correlated with rapid (<6 s) dendritic beading. Dendrites quickly (<3 min) recovered between SDs to near-control morphology until the occurrence of SD-induced terminal dendritic injury, signifying acute synaptic damage. SDs are characterized by a breakdown of ion homeostasis that can be recovered by ion pumps if the energy supply is adequate. Indeed, the likelihood of rapid dendritic recovery between SDs was correlated with the presence of nearby flowing blood vessels, but the presence of such vessels was not always sufficient for rapid dendritic recovery, suggesting that energy needs for recovery exceeded energy supply of compromised blood flow. We propose that metabolic stress resulting from recurring SDs facilitates acute injury at the level of dendrites and dendritic spines in metabolically compromised tissue, expediting penumbral recruitment into the ischemic core.
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Affiliation(s)
- W. Christopher Risher
- Graduate Program in Neuroscience
- Brain and Behavioral Discovery Institute, Medical College of Georgia, Augusta, Georgia 30912
| | - Deborah Ard
- Department of Neurosurgery, and
- Brain and Behavioral Discovery Institute, Medical College of Georgia, Augusta, Georgia 30912
| | - Jianghe Yuan
- Brain and Behavioral Discovery Institute, Medical College of Georgia, Augusta, Georgia 30912
| | - Sergei A. Kirov
- Department of Neurosurgery, and
- Brain and Behavioral Discovery Institute, Medical College of Georgia, Augusta, Georgia 30912
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Brady JD, Mohr C, Rossi DJ. Vesicular GABA release delays the onset of the Purkinje cell terminal depolarization without affecting tissue swelling in cerebellar slices during simulated ischemia. Neuroscience 2010; 168:108-17. [PMID: 20226232 DOI: 10.1016/j.neuroscience.2010.03.009] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2009] [Revised: 02/02/2010] [Accepted: 03/04/2010] [Indexed: 10/19/2022]
Abstract
Neurosteroids that can enhance GABA(A) receptor sensitivity protect cerebellar Purkinje cells against transient episodes of global brain ischemia, but little is known about how ischemia affects GABAergic transmission onto Purkinje cells. Here we use patch-clamp recording from Purkinje cells in acutely prepared slices of rat cerebellum to determine how ischemia affects GABAergic signaling to Purkinje cells. In voltage-clamped Purkinje cells, exposing slices to solutions designed to simulate brain ischemia caused an early, partial suppression of the frequency of spontaneous inhibitory post synaptic currents (sIPSCs), but after 5-8 min GABA accumulated in the extracellular space around Purkinje cells, generating a large (approximately 17 nS), sustained GABA(A) receptor-mediated conductance. The sustained GABA(A) conductance occurred in parallel with an even larger (approximately 117 nS) glutamate receptor-mediated conductance, but blocking GABA(A) receptors did not affect the timing or magnitude of the glutamate conductance, and blocking glutamate receptors did not affect the timing or magnitude of the GABA(A) conductance. Despite the lack of interaction between GABA and glutamate, blocking GABA(A) receptors significantly accelerated the onset of the Purkinje cell "ischemic" depolarization (ID), as assessed with current-clamp recordings from Purkinje cells or field potential recordings in the dendritic field of the Purkinje cells. The Purkinje cell ID occurred approximately 2 min prior to the sustained glutamate release under control conditions and a further 1-2 min earlier when GABA(A) receptors were blocked. Tissue swelling, as assessed by monitoring light transmittance through the slice, peaked just after the ID, prior to the sustained glutamate release, but was not affected by blocking GABA(A) receptors. These data indicate that ischemia induces the Purkinje cell ID and tissue swelling prior to the sustained glutamate release, and that blocking GABA(A) receptors accelerates the onset of the ID without affecting tissue swelling. Taken together these data may explain why Purkinje cells are one of the most ischemia sensitive neurons in the brain despite lacking NMDA receptors, and why neurosteroids that enhance GABA(A) receptor function protect Purkinje cells against transient episodes of global brain ischemia.
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Affiliation(s)
- J D Brady
- Department of Behavioral Neuroscience, Oregon Health and Science University, 505 NW 185th Avenue, Beaverton, OR 97006, USA
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Armogida M, Giustizieri M, Zona C, Piccirilli S, Nisticò R, Mercuri NB. N-ethyl lidocaine (QX-314) protects striatal neurons against ischemia: an in vitro electrophysiological study. Synapse 2010; 64:161-8. [PMID: 19852070 DOI: 10.1002/syn.20735] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
In this study, we have investigated the neuroprotective actions of the membrane impermeable, lidocaine analog, N-ethyl lidocaine (QX-314) in the striatum. The effects of this drug were compared with those caused by the strictly-related-compound and sodium channel blocker lidocaine. To address this issue, electrophysiological recordings were performed in striatal slices, in control condition (normoxia) and during combined oxygen and glucose deprivation (in vitro ischemia). Either QX-314 or lidocaine induced, to some extent, a protection of the permanent electrophysiological alteration (field potential loss) caused by a period (12 min) of ischemia. Thus, both compounds permitted a partial recovery of the ischemic depression of the corticostriatal transmission and reduced the amplitude of the ischemic depolarization in medium spiny neurons. However, while QX-314, at the effective concentration of 100 microM, slightly reduced the amplitude of the excitatory field potential and did not affect the current-evoked spikes discharge of medium spiny striatal neurons, equimolar lidocaine depressed the field potential and eliminated repetitive spikes on a depolarizing step. On the basis of these observations, our results suggest the use of QX-314 as a neuroprotective agent in ischemic brain disorders.
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Affiliation(s)
- Marta Armogida
- Laboratory of Experimental Neurology, Fondazione Santa Lucia IRCCS, Rome, Italy
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Abstract
Chaperones are proteins that assist the correct folding of other protein clients either when the clients are being synthesized or at their functional localities. Chaperones are responsible for certain diseases. The sigma-1 receptor is recently identified as a receptor chaperone whose activity can be activated/deactivated by specific ligands. Under physiological conditions, the sigma-1 receptor chaperones the functional IP3 receptor at the endoplasmic reticulum and mitochondrion interface to ensure proper Ca(2+) signaling from endoplasmic reticulum into mitochondrion. However, under pathological conditions whereby cells encounter enormous stress that results in the endoplasmic reticulum losing its global Ca(2+) homeostasis, the sigma-1 receptor translocates and counteracts the arising apoptosis. Thus, the sigma-1 receptor is a receptor chaperone essential for the metabotropic receptor signaling and for the survival against cellular stress. The sigma-1 receptor has been implicated in many diseases including addiction, pain, depression, stroke, and cancer. Whether the chaperone activity of the sigma-1 receptor attributes to those diseases awaits further investigation.
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Affiliation(s)
- Shang-Yi Tsai
- Cellular Pathobiology Section, Cellular Neurobiology Research Branch, IRP, NIDA, NIH, DHHS, 333 Cassell Drive, Baltimore, MD 21224, USA
| | - Teruo Hayashi
- Cellular Pathobiology Section, Cellular Neurobiology Research Branch, IRP, NIDA, NIH, DHHS, 333 Cassell Drive, Baltimore, MD 21224, USA
| | - Tomohisa Mori
- Cellular Pathobiology Section, Cellular Neurobiology Research Branch, IRP, NIDA, NIH, DHHS, 333 Cassell Drive, Baltimore, MD 21224, USA
| | - Tsung-Ping Su
- Cellular Pathobiology Section, Cellular Neurobiology Research Branch, IRP, NIDA, NIH, DHHS, 333 Cassell Drive, Baltimore, MD 21224, USA
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Dave KR, Anthony Defazio R, Raval AP, Dashkin O, Saul I, Iceman KE, Perez-Pinzon MA, Drew KL. Protein kinase C epsilon activation delays neuronal depolarization during cardiac arrest in the euthermic arctic ground squirrel. J Neurochem 2009; 110:1170-9. [PMID: 19493168 PMCID: PMC2774829 DOI: 10.1111/j.1471-4159.2009.06196.x] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
During the pre-hibernation season, arctic ground squirrels (AGS) can tolerate 8 min of asphyxial cardiac arrest (CA) without detectable brain pathology. Better understanding of the mechanisms regulating innate ischemia tolerance in AGS has the potential to facilitate the development of novel prophylactic agents to induce ischemic tolerance in patients at risk of stroke or CA. We hypothesized that neuroprotection in AGS involves robust maintenance of ion homeostasis similar to anoxia-tolerant turtles. Ion homeostasis was assessed by monitoring ischemic depolarization (ID) in cerebral cortex during CA in vivo and during oxygen glucose deprivation in vitro in acutely prepared hippocampal slices. In both models, the onset of ID was significantly delayed in AGS compared with rats. The epsilon protein kinase C (epsilonPKC) is a key mediator of neuroprotection and inhibits both Na+/K+-ATPase and voltage-gated sodium channels, primary mediators of the collapse of ion homeostasis during ischemia. The selective peptide inhibitor of epsilonPKC (epsilonV1-2) shortened the time to ID in brain slices from AGS but not in rats despite evidence that epsilonV1-2 decreased activation of epsilonPKC in brain slices from both rats and AGS. These results support the hypothesis that epsilonPKC activation delays the collapse of ion homeostasis during ischemia in AGS.
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Affiliation(s)
- Kunjan R Dave
- Department of Neurology, Cerebral Vascular Disease Research Center, Leonard M. Miller School of Medicine, University of Miami, Miami, Florida 33101, USA.
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Risher WC, Andrew RD, Kirov SA. Real-time passive volume responses of astrocytes to acute osmotic and ischemic stress in cortical slices and in vivo revealed by two-photon microscopy. Glia 2009; 57:207-21. [PMID: 18720409 DOI: 10.1002/glia.20747] [Citation(s) in RCA: 166] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
The brain swells over the several minutes that follow stroke onset or acute hypo-osmotic stress because cells take up water. Measuring the volume responses of single neurons and glia has necessarily been confined to isolated or cultured cells. Two-photon laser scanning microscopy enables real-time visualization of cells functioning deep within living neocortex in vivo or in brain slices under physiologically relevant osmotic and ischemic stress. Astrocytes and their processes expressing green fluorescent protein in murine cortical slices swelled in response to 20 min of overhydration (-40 mOsm) and shrank during dehydration (+40 or +80 mOsm) at 32-34 degrees C. Minute-by-minute monitoring revealed no detectable volume regulation during these osmotic challenges, particularly during the first 5 min. Astrocytes also rapidly swelled in response to elevated [K+](o) for 3 min or oxygen/glucose deprivation (OGD) for 10 min. Post-OGD, astroglial volume recovered quickly when slices were re-supplied with oxygen and glucose, while neurons remained swollen with beaded dendrites. In vivo, rapid astroglial swelling was confirmed within 6 min following intraperitoneal water injection or during the 6-12 min following cardiac arrest. While the astrocytic processes were clearly swollen, the extent of the astroglial arbor remained unchanged. Thus, in contrast to osmo-resistant pyramidal neurons (Andrew et al., 2007) that lack known aquaporins, astrocytes passively respond to acute osmotic stress, reflecting functional aquaporins in their plasma membrane. Unlike neurons, astrocytes better recover from brief ischemic insult in cortical slices, probably because their aquaporins facilitate water efflux.
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Pamenter ME, Buck LT. Neuronal membrane potential is mildly depolarized in the anoxic turtle cortex. Comp Biochem Physiol A Mol Integr Physiol 2008; 150:410-4. [PMID: 18519169 DOI: 10.1016/j.cbpa.2008.04.605] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2008] [Revised: 04/21/2008] [Accepted: 04/22/2008] [Indexed: 11/17/2022]
Abstract
Neuronal membrane potential (E(m)) regulates the activity of excitatory voltage-sensitive channels. Anoxic insults lead to a severe loss of E(m) and excitotoxic cell death (ECD) in mammalian neurons. Conversely, anoxia-tolerant freshwater turtle neurons depress energy usage during anoxia by altering ionic conductance to reduce neuronal excitability and ECD is avoided. This wholesale alteration of ion channel and pump activity likely has a significant effect on E(m). Using the whole-cell patch clamp technique we recorded changes in E(m) from turtle cortical neurons during a normoxic to anoxic transition in the presence of various ion channel/pump modulators. E(m) did not change with normoxic perfusion but underwent a reversible, mild depolarization of 8.1+/-0.2 mV following anoxic perfusion. This mild anoxic depolarization (MAD) was not prevented by the manipulation of any single ionic conductance, but was partially reduced by pre-treatment with antagonists of GABA(A) receptors (5.7+/-0.5 mV), cellular bicarbonate production (5.3+/-0.2 mV) or K(+) channels (6.0+/-0.2 mV), or by perfusion of reactive oxygen species scavengers (5.2+/-0.3 mV). Furthermore, all of these treatments induced depolarization in normoxic neurons. Together these data suggest that the MAD may be due to the summation of numerous altered ion conductance states during anoxia.
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