1
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Al-Karagholi MAM, Arngrim N, Ashina M. Migraine headache and aura induced by hypoxia. J Physiol 2024. [PMID: 38279931 DOI: 10.1113/jp284553] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2023] [Accepted: 01/03/2024] [Indexed: 01/29/2024] Open
Abstract
Migraine, a common neurological disorder, impacts over a billion individuals globally. Its complex aetiology involves various signalling cascades. Hypoxia causes headaches such as high-altitude headache and acute mountain sickness which share phenotypical similarities with migraine. Epidemiological data indicate an increased prevalence of migraine with and without aura in high-altitude populations. Experimental studies have further shown that hypoxia can induce migraine attacks. This review summarizes evidence linking hypoxia to migraine, delves into potential pathophysiological mechanisms and highlights research gaps.
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Affiliation(s)
| | - Nanna Arngrim
- Department of Neurology, Odense University Hospital, Denmark
| | - Messoud Ashina
- Department of Neurology, Danish Headache Center, Copenhagen University Hospital-Rigshospitalet, Copenhagen, Denmark
- Danish Knowledge Center on Headache Disorders, Glostrup, Denmark
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2
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Eighteen-hour inhibitory effect of s-ketamine on potassium- and ischemia-induced spreading depolarizations in the gyrencephalic swine brain. Neuropharmacology 2022; 216:109176. [DOI: 10.1016/j.neuropharm.2022.109176] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2022] [Revised: 05/15/2022] [Accepted: 06/28/2022] [Indexed: 11/18/2022]
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3
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Hashem M, Wu Y, Dunn JF. Quantification of cytochrome c oxidase and tissue oxygenation using CW-NIRS in a mouse cerebral cortex. BIOMEDICAL OPTICS EXPRESS 2021; 12:7632-7656. [PMID: 35003857 PMCID: PMC8713667 DOI: 10.1364/boe.435532] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/01/2021] [Revised: 10/06/2021] [Accepted: 11/05/2021] [Indexed: 05/05/2023]
Abstract
We provide a protocol for measuring the absolute concentration of the oxidized and reduced state of cytochrome c oxidase (CCO) in the cerebral cortex of mice, using broadband continuous-wave NIRS. The algorithm (NIR-AQUA) allows for absolute quantification of CCO and deoxyhemoglobin. Combined with an anoxia pulse, this also allows for quantification of total hemoglobin, and tissue oxygen saturation. CCO in the cortex was 4.9 ± 0.1 μM (mean ± SD, n=6). In normoxia, 84% of CCO was oxidized. We include hypoxia and cyanide validation studies to show CCO can be quantified independently to hemoglobin. This can be applied to study oxidative metabolism in the many rodent models of neurological disease.
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Affiliation(s)
- Mada Hashem
- Biomedical Engineering Graduate Program, University of Calgary, Calgary, Alberta, Canada T2N 4N1, Canada
- Department of Radiology, Faculty of Medicine, University of Calgary, Calgary, Alberta, Canada T2N 4N1, Canada
- Hotchkiss Brain Institute, University of Calgary, Alberta, Canada T2N 4N1, Canada
- Experimental Imaging Centre, Cumming School of Medicine, University of Calgary, Alberta, Canada T2N 4N1, Canada
| | - Ying Wu
- Department of Radiology, Faculty of Medicine, University of Calgary, Calgary, Alberta, Canada T2N 4N1, Canada
- Hotchkiss Brain Institute, University of Calgary, Alberta, Canada T2N 4N1, Canada
- Experimental Imaging Centre, Cumming School of Medicine, University of Calgary, Alberta, Canada T2N 4N1, Canada
| | - Jeff F. Dunn
- Department of Radiology, Faculty of Medicine, University of Calgary, Calgary, Alberta, Canada T2N 4N1, Canada
- Hotchkiss Brain Institute, University of Calgary, Alberta, Canada T2N 4N1, Canada
- Experimental Imaging Centre, Cumming School of Medicine, University of Calgary, Alberta, Canada T2N 4N1, Canada
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4
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Lu YL, Scharfman HE. New Insights and Methods for Recording and Imaging Spontaneous Spreading Depolarizations and Seizure-Like Events in Mouse Hippocampal Slices. Front Cell Neurosci 2021; 15:761423. [PMID: 34899190 PMCID: PMC8663723 DOI: 10.3389/fncel.2021.761423] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2021] [Accepted: 10/04/2021] [Indexed: 11/30/2022] Open
Abstract
Spreading depolarization (SD) is a sudden, large, and synchronous depolarization of principal cells which also involves interneurons and astrocytes. It is followed by depression of neuronal activity, and it slowly propagates across brain regions like cortex or hippocampus. SD is considered to be mechanistically relevant to migraine, epilepsy, and traumatic brain injury (TBI), but there are many questions about its basic neurophysiology and spread. Research into SD in hippocampus using slices is often used to gain insight and SD is usually triggered by a focal stimulus with or without an altered extracellular buffer. Here, we optimize an in vitro experimental model allowing us to record SD without focal stimulation, which we call spontaneous. This method uses only an altered extracellular buffer containing 0 mM Mg2+ and 5 mM K+ and makes it possible for simultaneous patch and extracellular recording in a submerged chamber plus intrinsic optical imaging in slices of either sex. We also add methods for quantification and show the quantified optical signal is much more complex than imaging alone would suggest. In brief, acute hippocampal slices were prepared with a chamber holding a submerged slice but with flow of artificial cerebrospinal fluid (aCSF) above and below, which we call interface-like. As soon as slices were placed in the chamber, aCSF with 0 Mg2+/5 K+ was used. Most mouse slices developed SD and did so in the first hour of 0 Mg2+/5 K+ aCSF exposure. In addition, prolonged bursts we call seizure-like events (SLEs) occurred, and the interactions between SD and SLEs suggest potentially important relationships. Differences between rats and mice in different chambers are described. Regarding optical imaging, SD originated in CA3 and the pattern of spread to CA1 and the dentate gyrus was similar in some ways to prior studies but also showed interesting differences. In summary, the methods are easy to use, provide new opportunities to study SD, new insights, and are inexpensive. They support previous suggestions that SD is diverse, and also suggest that participation by the dentate gyrus merits greater attention.
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Affiliation(s)
- Yi-Ling Lu
- Center for Dementia Research, The Nathan Kline Institute for Psychiatric Research, Orangeburg, NY, United States
| | - Helen E. Scharfman
- Center for Dementia Research, The Nathan Kline Institute for Psychiatric Research, Orangeburg, NY, United States
- Department of Child and Adolescent Psychiatry, New York University Langone Health, New York, NY, United States
- Department of Neuroscience and Physiology, New York University Langone Health, New York, NY, United States
- Department of Psychiatry, New York University Langone Health, New York, NY, United States
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5
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Brainstem and Cortical Spreading Depolarization in a Closed Head Injury Rat Model. Int J Mol Sci 2021; 22:ijms222111642. [PMID: 34769073 PMCID: PMC8584184 DOI: 10.3390/ijms222111642] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2021] [Revised: 10/14/2021] [Accepted: 10/25/2021] [Indexed: 11/17/2022] Open
Abstract
Traumatic brain injury (TBI) is the leading cause of death in young individuals, and is a major health concern that often leads to long-lasting complications. However, the electrophysiological events that occur immediately after traumatic brain injury, and may underlie impact outcomes, have not been fully elucidated. To investigate the electrophysiological events that immediately follow traumatic brain injury, a weight-drop model of traumatic brain injury was used in rats pre-implanted with epidural and intracerebral electrodes. Electrophysiological (near-direct current) recordings and simultaneous alternating current recordings of brain activity were started within seconds following impact. Cortical spreading depolarization (SD) and SD-induced spreading depression occurred in approximately 50% of mild and severe impacts. SD was recorded within three minutes after injury in either one or both brain hemispheres. Electrographic seizures were rare. While both TBI- and electrically induced SDs resulted in elevated oxidative stress, TBI-exposed brains showed a reduced antioxidant defense. In severe TBI, brainstem SD could be recorded in addition to cortical SD, but this did not lead to the death of the animals. Severe impact, however, led to immediate death in 24% of animals, and was electrocorticographically characterized by non-spreading depression (NSD) of activity followed by terminal SD in both cortex and brainstem.
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6
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Oliveira-Ferreira AI, Major S, Przesdzing I, Kang EJ, Dreier JP. Spreading depolarizations in the rat endothelin-1 model of focal cerebellar ischemia. J Cereb Blood Flow Metab 2020; 40:1274-1289. [PMID: 31280632 PMCID: PMC7232780 DOI: 10.1177/0271678x19861604] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
Focal brain ischemia is best studied in neocortex and striatum. Both show highly vulnerable neurons and high susceptibility to spreading depolarization (SD). Therefore, it has been hypothesized that these two variables generally correlate. However, this hypothesis is contradicted by findings in cerebellar cortex, which contains highly vulnerable neurons to ischemia, the Purkinje cells, but is said to be less susceptible to SD. Here, we found in the rat cerebellar cortex that elevated K+ induced a long-lasting depolarizing event superimposed with SDs. Cerebellar SDs resembled those in neocortex, but negative direct current (DC) shifts and regional blood flow responses were usually smaller. The K+ threshold for SD was higher in cerebellum than in previous studies in neocortex. We then topically applied endothelin-1 (ET-1) to the cerebellum, which is assumed to cause SD via vasoconstriction-induced focal ischemia. Although the blood flow decrease was similar to that in previous studies in neocortex, the ET-1 threshold for SD was higher. Quantitative cell counting found that the proportion of necrotic Purkinje cells was significantly higher in ET-1-treated rats than sham controls even if ET-1 had not caused SDs. Our results suggest that ischemic death of Purkinje cells does not require the occurrence of SD.
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Affiliation(s)
- Ana I Oliveira-Ferreira
- Center for Stroke Research Berlin, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany.,Department of Experimental Neurology, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
| | - Sebastian Major
- Center for Stroke Research Berlin, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany.,Department of Experimental Neurology, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany.,Department of Neurology, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
| | - Ingo Przesdzing
- Center for Stroke Research Berlin, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany.,Department of Experimental Neurology, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
| | - Eun-Jeung Kang
- Center for Stroke Research Berlin, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany.,Department of Experimental Neurology, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
| | - Jens P Dreier
- Center for Stroke Research Berlin, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany.,Department of Experimental Neurology, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany.,Department of Neurology, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and 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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7
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Major S, Huo S, Lemale CL, Siebert E, Milakara D, Woitzik J, Gertz K, Dreier JP. Direct electrophysiological evidence that spreading depolarization-induced spreading depression is the pathophysiological correlate of the migraine aura and a review of the spreading depolarization continuum of acute neuronal mass injury. GeroScience 2020; 42:57-80. [PMID: 31820363 PMCID: PMC7031471 DOI: 10.1007/s11357-019-00142-7] [Citation(s) in RCA: 42] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2019] [Accepted: 11/20/2019] [Indexed: 02/07/2023] Open
Abstract
Spreading depolarization is observed as a large negative shift of the direct current potential, swelling of neuronal somas, and dendritic beading in the brain's gray matter and represents a state of a potentially reversible mass injury. Its hallmark is the abrupt, massive ion translocation between intraneuronal and extracellular compartment that causes water uptake (= cytotoxic edema) and massive glutamate release. Dependent on the tissue's energy status, spreading depolarization can co-occur with different depression or silencing patterns of spontaneous activity. In adequately supplied tissue, spreading depolarization induces spreading depression of activity. In severely ischemic tissue, nonspreading depression of activity precedes spreading depolarization. The depression pattern determines the neurological deficit which is either spreading such as in migraine aura or migraine stroke or nonspreading such as in transient ischemic attack or typical stroke. Although a clinical distinction between spreading and nonspreading focal neurological deficits is useful because they are associated with different probabilities of permanent damage, it is important to note that spreading depolarization, the neuronal injury potential, occurs in all of these conditions. Here, we first review the scientific basis of the continuum of spreading depolarizations. Second, we highlight the transition zone of the continuum from reversibility to irreversibility using clinical cases of aneurysmal subarachnoid hemorrhage and cerebral amyloid angiopathy. These illustrate how modern neuroimaging and neuromonitoring technologies increasingly bridge the gap between basic sciences and clinic. For example, we provide direct electrophysiological evidence for the first time that spreading depolarization-induced spreading depression is the pathophysiological correlate of the migraine aura.
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Affiliation(s)
- Sebastian Major
- Center for Stroke Research, Campus Charité Mitte, Charité University Medicine Berlin, Charitéplatz 1, 10117, Berlin, Germany
- Department of Experimental Neurology, Charité-Universitätsmedizin Berlin, Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
- Department of Neurology, Charité-Universitätsmedizin Berlin, Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
| | - Shufan Huo
- Center for Stroke Research, Campus Charité Mitte, Charité University Medicine Berlin, Charitéplatz 1, 10117, Berlin, Germany
- Department of Neurology, Charité-Universitätsmedizin Berlin, Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
| | - Coline L Lemale
- Center for Stroke Research, Campus Charité Mitte, Charité University Medicine Berlin, Charitéplatz 1, 10117, Berlin, Germany
- Department of Experimental Neurology, Charité-Universitätsmedizin Berlin, Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
| | - Eberhard Siebert
- Department of Neuroradiology, Charité-Universitätsmedizin Berlin, Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
| | - Denny Milakara
- Solution Centre for Image Guided Local Therapies (STIMULATE), Otto-von-Guericke-University, Magdeburg, Germany
| | - Johannes Woitzik
- Evangelisches Krankenhaus Oldenburg, University of Oldenburg, Oldenburg, Germany
| | - Karen Gertz
- Center for Stroke Research, Campus Charité Mitte, Charité University Medicine Berlin, Charitéplatz 1, 10117, Berlin, Germany
- Department of Experimental Neurology, Charité-Universitätsmedizin Berlin, Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
- Department of Neurology, Charité-Universitätsmedizin Berlin, Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
| | - Jens P Dreier
- Center for Stroke Research, Campus Charité Mitte, Charité University Medicine Berlin, Charitéplatz 1, 10117, Berlin, Germany.
- Department of Experimental Neurology, Charité-Universitätsmedizin Berlin, Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany.
- Department of Neurology, Charité-Universitätsmedizin Berlin, Freie Universität Berlin, Humboldt-Universität zu Berlin, and 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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8
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Arngrim N, Hougaard A, Schytz HW, Vestergaard MB, Britze J, Amin FM, Olsen KS, Larsson HB, Olesen J, Ashina M. Effect of hypoxia on BOLD fMRI response and total cerebral blood flow in migraine with aura patients. J Cereb Blood Flow Metab 2019; 39:680-689. [PMID: 28686073 PMCID: PMC6446416 DOI: 10.1177/0271678x17719430] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Experimentally induced hypoxia triggers migraine and aura attacks in patients suffering from migraine with aura (MA). We investigated the blood oxygenation level-dependent (BOLD) signal response to visual stimulation during hypoxia in MA patients and healthy volunteers. In a randomized double-blind crossover study design, 15 MA patients were allocated to 180 min of normobaric poikilocapnic hypoxia (capillary oxygen saturation 70-75%) or sham (normoxia) on two separate days and 14 healthy volunteers were exposed to hypoxia. The BOLD functional MRI (fMRI) signal response to visual stimulation was measured in the visual cortex ROIs V1-V5. Total cerebral blood flow (CBF) was calculated by measuring the blood velocity in the internal carotid arteries and the basilar artery using phase-contrast mapping (PCM) MRI. Hypoxia induced a greater decrease in BOLD response to visual stimulation in V1-V4 in MA patients compared to controls. There was no group difference in hypoxia-induced total CBF increase. In conclusion, the study demonstrated a greater hypoxia-induced decrease in BOLD response to visual stimulation in MA patients. We suggest this may represent a hypoxia-induced change in neuronal excitability or abnormal vascular response to visual stimulation, which may explain the increased sensibility to hypoxia in these patients leading to migraine attacks.
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Affiliation(s)
- Nanna Arngrim
- 1 Danish Headache Center and Department of Neurology, University of Copenhagen, Copenhagen, Denmark
| | - Anders Hougaard
- 1 Danish Headache Center and Department of Neurology, University of Copenhagen, Copenhagen, Denmark
| | - Henrik W Schytz
- 1 Danish Headache Center and Department of Neurology, University of Copenhagen, Copenhagen, Denmark
| | - Mark B Vestergaard
- 2 Department of Clinical Physiology, Nuclear Medicine and PET, Functional Imaging Unit, University of Copenhagen, Copenhagen, Denmark
| | - Josefine Britze
- 1 Danish Headache Center and Department of Neurology, University of Copenhagen, Copenhagen, Denmark
| | - Faisal Mohammad Amin
- 1 Danish Headache Center and Department of Neurology, University of Copenhagen, Copenhagen, Denmark
| | - Karsten S Olsen
- 3 Department of Neuroanaesthesiology, The Neuroscience Centre, Rigshospitalet Glostrup, Faculty of Health and Medical Sciences, University of Copenhagen, Glostrup, Denmark
| | - Henrik Bw Larsson
- 2 Department of Clinical Physiology, Nuclear Medicine and PET, Functional Imaging Unit, University of Copenhagen, Copenhagen, Denmark
| | - Jes Olesen
- 1 Danish Headache Center and Department of Neurology, University of Copenhagen, Copenhagen, Denmark
| | - Messoud Ashina
- 1 Danish Headache Center and Department of Neurology, University of Copenhagen, Copenhagen, Denmark
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9
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Benkő Z, Moldován K, Szádeczky-Kardoss K, Zalányi L, Borbély S, Világi I, Somogyvári Z. Causal relationship between local field potential and intrinsic optical signal in epileptiform activity in vitro. Sci Rep 2019; 9:5171. [PMID: 30914731 PMCID: PMC6435742 DOI: 10.1038/s41598-019-41554-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2018] [Accepted: 03/11/2019] [Indexed: 11/10/2022] Open
Abstract
The directed causal relationship were examined between the local field potential (LFP) and the intrinsic optical signal (IOS) during induced epileptiform activity in in vitro cortical slices by the convergent cross-mapping causality analysis method. Two components of the IOS signal have been distinguished: a faster, activity dependent component (IOSh) which changes its sign between transmitted and reflected measurement, thus it is related to the reflectance or the scattering of the tissue and a slower component (IOSl), which is negative in both cases, thus it is resulted by the increase of the absorption of the tissue. We have found a strong, unidirectional, delayed causal effect from LFP to IOSh with 0.5-1s delay, without signs of feedback from the IOSh to the LFP, while the correlation was small and the peaks of the cross correlation function did not reflect the actual causal dependency. Based on these observations, a model has been set up to describe the dependency of the IOSh on the LFP power and IOSh was reconstructed, based on the LFP signal. This study demonstrates that causality analysis can lead to better understanding the physiological interactions, even in case of two data series with drastically different time scales.
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Affiliation(s)
- Zsigmond Benkő
- Theoretical Neuroscience and Complex Systems Research Group, Department of Computational Sciences, Wigner Research Center for Physics of the Hungarian Academy of Sciences, Budapest, H-1121, Hungary.,János Szentágothai Doctoral School of Neurosciences, Semmelweis University, Budapest, H-1085, Hungary
| | - Kinga Moldován
- Department of Physiology and Neurobiology, Eötvös Loránd University, Budapest, H-1117, Hungary
| | | | - László Zalányi
- Theoretical Neuroscience and Complex Systems Research Group, Department of Computational Sciences, Wigner Research Center for Physics of the Hungarian Academy of Sciences, Budapest, H-1121, Hungary
| | - Sándor Borbély
- Department of Physiology and Neurobiology, Eötvös Loránd University, Budapest, H-1117, Hungary
| | - Ildikó Világi
- Department of Physiology and Neurobiology, Eötvös Loránd University, Budapest, H-1117, Hungary
| | - Zoltán Somogyvári
- Theoretical Neuroscience and Complex Systems Research Group, Department of Computational Sciences, Wigner Research Center for Physics of the Hungarian Academy of Sciences, Budapest, H-1121, Hungary. .,Neuromicrosystems ltd., Budapest, H-1113, Hungary.
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10
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Woo J, Han YE, Koh W, Won J, Park MG, An H, Lee CJ. Pharmacological Dissection of Intrinsic Optical Signal Reveals a Functional Coupling between Synaptic Activity and Astrocytic Volume Transient. Exp Neurobiol 2019; 28:30-42. [PMID: 30853822 PMCID: PMC6401548 DOI: 10.5607/en.2019.28.1.30] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2019] [Revised: 02/12/2019] [Accepted: 02/14/2019] [Indexed: 11/19/2022] Open
Abstract
The neuronal activity-dependent change in the manner in which light is absorbed or scattered in brain tissue is called the intrinsic optical signal (IOS), and provides label-free, minimally invasive, and high spatial (~100 µm) resolution imaging for visualizing neuronal activity patterns. IOS imaging in isolated brain slices measured at an infrared wavelength (>700 nm) has recently been attributed to the changes in light scattering and transmittance due to aquaporin-4 (AQP4)-dependent astrocytic swelling. The complexity of functional interactions between neurons and astrocytes, however, has prevented the elucidation of the series of molecular mechanisms leading to the generation of IOS. Here, we pharmacologically dissected the IOS in the acutely prepared brain slices of the stratum radiatum of the hippocampus, induced by 1 s/20 Hz electrical stimulation of Schaffer-collateral pathway with simultaneous measurement of the activity of the neuronal population by field potential recordings. We found that 55% of IOSs peak upon stimulation and originate from postsynaptic AMPA and NMDA receptors. The remaining originated from presynaptic action potentials and vesicle fusion. Mechanistically, the elevated extracellular glutamate and K+ during synaptic transmission were taken up by astrocytes via a glutamate transporter and quinine-sensitive K2P channel, followed by an influx of water via AQP-4. We also found that the decay of IOS is mediated by the DCPIB- and NPPB-sensitive anion channels in astrocytes. Altogether, our results demonstrate that the functional coupling between synaptic activity and astrocytic transient volume change during excitatory synaptic transmission is the major source of IOS.
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Affiliation(s)
- Junsung Woo
- Center for Glia-Neuron Interaction, Korea Institute of Science and Technology (KIST), Seoul 02792, Korea
| | - Young-Eun Han
- Center for Glia-Neuron Interaction, Korea Institute of Science and Technology (KIST), Seoul 02792, Korea.,Department of Neuroscience, Division of Bio-medical Science & Technology, KIST School, Korea University of Science and Technology, Seoul 02792, Korea.,Center for Cognition and Sociality, Institute for Basic Science (IBS), Daejeon 34126, Korea
| | - Wuhyun Koh
- Center for Glia-Neuron Interaction, Korea Institute of Science and Technology (KIST), Seoul 02792, Korea.,Department of Neuroscience, Division of Bio-medical Science & Technology, KIST School, Korea University of Science and Technology, Seoul 02792, Korea.,Center for Cognition and Sociality, Institute for Basic Science (IBS), Daejeon 34126, Korea
| | - Joungha Won
- Center for Glia-Neuron Interaction, Korea Institute of Science and Technology (KIST), Seoul 02792, Korea.,Center for Cognition and Sociality, Institute for Basic Science (IBS), Daejeon 34126, Korea.,Department of Biological Sciences, Korea Advanced Institutes of Science and Technology (KAIST), Daejeon 34141, Korea
| | - Min Gu Park
- Center for Glia-Neuron Interaction, Korea Institute of Science and Technology (KIST), Seoul 02792, Korea.,Center for Cognition and Sociality, Institute for Basic Science (IBS), Daejeon 34126, Korea.,KU-KIST, Graduate School of Converging Science and Technology, Korea University, Seoul 02841, Korea
| | - Heeyoung An
- Center for Glia-Neuron Interaction, Korea Institute of Science and Technology (KIST), Seoul 02792, Korea.,Center for Cognition and Sociality, Institute for Basic Science (IBS), Daejeon 34126, Korea.,KU-KIST, Graduate School of Converging Science and Technology, Korea University, Seoul 02841, Korea
| | - C Justin Lee
- Center for Glia-Neuron Interaction, Korea Institute of Science and Technology (KIST), Seoul 02792, Korea.,Department of Neuroscience, Division of Bio-medical Science & Technology, KIST School, Korea University of Science and Technology, Seoul 02792, Korea.,Center for Cognition and Sociality, Institute for Basic Science (IBS), Daejeon 34126, Korea
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11
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Dreier JP, Lemale CL, Kola V, Friedman A, Schoknecht K. Spreading depolarization is not an epiphenomenon but the principal mechanism of the cytotoxic edema in various gray matter structures of the brain during stroke. Neuropharmacology 2017; 134:189-207. [PMID: 28941738 DOI: 10.1016/j.neuropharm.2017.09.027] [Citation(s) in RCA: 124] [Impact Index Per Article: 17.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2017] [Revised: 09/16/2017] [Accepted: 09/19/2017] [Indexed: 12/15/2022]
Abstract
Spreading depolarization (SD) is a phenomenon of various cerebral gray matter structures that only occurs under pathological conditions. In the present paper, we summarize the evidence from several decades of research that SD and cytotoxic edema in these structures are largely overlapping terms. SD/cytotoxic edema is a toxic state that - albeit initially reversible - leads eventually to cellular death when it is persistent. Both hemorrhagic and ischemic stroke are among the most prominent causes of SD/cytotoxic edema. SD/cytotoxic edema is the principal mechanism that mediates neuronal death in these conditions. This applies to gray matter structures in both the ischemic core and the penumbra. SD/cytotoxic edema is often a single terminal event in the core whereas, in the penumbra, a cluster of repetitive prolonged SDs is typical. SD/cytotoxic edema also propagates widely into healthy surrounding tissue as short-lasting, relatively harmless events so that regional electrocorticographic monitoring affords even remote detection of ischemic zones. Ischemia cannot only cause SD/cytotoxic edema but it can also be its consequence through inverse neurovascular coupling. Under this condition, ischemia does not start simultaneously in different regions but spreads in the tissue driven by SD/cytotoxic edema-induced microvascular constriction (= spreading ischemia). Spreading ischemia prolongs SD/cytotoxic edema. Thus, it increases the likelihood for the transition from SD/cytotoxic edema into cellular death. Vasogenic edema is the other major type of cerebral edema with relevance to ischemic stroke. It results from opening of the blood-brain barrier. SD/cytotoxic edema and vasogenic edema are distinct processes with important mutual interactions. This article is part of the Special Issue entitled 'Cerebral Ischemia'.
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Affiliation(s)
- Jens P Dreier
- Center for Stroke Research Berlin, Charité-Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin Institute of Health, Berlin, Germany; Departments of Neurology, Charité-Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin Institute of Health, Berlin, Germany; Experimental Neurology, Charité-Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin Institute of Health, Berlin, Germany.
| | - Coline L Lemale
- Center for Stroke Research Berlin, Charité-Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin Institute of Health, Berlin, Germany
| | - Vasilis Kola
- Center for Stroke Research Berlin, Charité-Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin Institute of Health, Berlin, Germany
| | - Alon Friedman
- Department of Physiology and Cell Biology, Zlotowski Center for Neuroscience, Ben-Gurion University of the Negev, Beer-Sheva, Israel; Department of Medical Neuroscience, Faculty of Medicine, Dalhousie University, Halifax, Canada
| | - Karl Schoknecht
- Center for Stroke Research Berlin, Charité-Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin Institute of Health, Berlin, Germany; Experimental Neurology, Charité-Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin Institute of Health, Berlin, Germany
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12
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Schöll MJ, Santos E, Sanchez-Porras R, Kentar M, Gramer M, Silos H, Zheng Z, Gang Y, Strong AJ, Graf R, Unterberg A, Sakowitz OW, Dickhaus H. Large field-of-view movement-compensated intrinsic optical signal imaging for the characterization of the haemodynamic response to spreading depolarizations in large gyrencephalic brains. J Cereb Blood Flow Metab 2017; 37:1706-1719. [PMID: 27677673 PMCID: PMC5435296 DOI: 10.1177/0271678x16668988] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Haemodynamic responses to spreading depolarizations (SDs) have an important role during the development of secondary brain damage. Characterization of the haemodynamic responses in larger brains, however, is difficult due to movement artefacts. Intrinsic optical signal (IOS) imaging, laser speckle flowmetry (LSF) and electrocorticography were performed in different configurations in three groups of in total 18 swine. SDs were elicited by topical application of KCl or occurred spontaneously after middle cerebral artery occlusion. Movement artefacts in IOS were compensated by an elastic registration algorithm during post-processing. Using movement-compensated IOS, we were able to differentiate between four components of optical changes, corresponding closely with haemodynamic variations measured by LSF. Compared with ECoG and LSF, our setup provides higher spatial and temporal resolution, as well as a better signal-to-noise ratio. Using IOS alone, we could identify the different zones of infarction in a large gyrencephalic middle cerebral artery occlusion pig model. We strongly suggest movement-compensated IOS for the investigation of the role of haemodynamic responses to SDs during the development of secondary brain damage and in particular to examine the effect of potential therapeutic interventions in gyrencephalic brains.
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Affiliation(s)
- Michael Johannes Schöll
- 1 Institute of Medical Biometry and Informatics, University Hospital Heidelberg, Heidelberg, Germany.,2 Department of Neurosurgery, University Hospital Heidelberg, Heidelberg, Germany
| | - Edgar Santos
- 2 Department of Neurosurgery, University Hospital Heidelberg, Heidelberg, Germany
| | - Renan Sanchez-Porras
- 2 Department of Neurosurgery, University Hospital Heidelberg, Heidelberg, Germany
| | - Modar Kentar
- 2 Department of Neurosurgery, University Hospital Heidelberg, Heidelberg, Germany
| | - Markus Gramer
- 3 Max Planck Institute for Metabolism Research, Cologne, Germany
| | - Humberto Silos
- 2 Department of Neurosurgery, University Hospital Heidelberg, Heidelberg, Germany
| | - Zelong Zheng
- 2 Department of Neurosurgery, University Hospital Heidelberg, Heidelberg, Germany
| | - Yuan Gang
- 2 Department of Neurosurgery, University Hospital Heidelberg, Heidelberg, Germany
| | - Anthony John Strong
- 4 Department of Basic and Clinical Neuroscience, King's College London, London, UK
| | - Rudolf Graf
- 3 Max Planck Institute for Metabolism Research, Cologne, Germany
| | - Andreas Unterberg
- 2 Department of Neurosurgery, University Hospital Heidelberg, Heidelberg, Germany
| | - Oliver W Sakowitz
- 2 Department of Neurosurgery, University Hospital Heidelberg, Heidelberg, Germany
| | - Hartmut Dickhaus
- 1 Institute of Medical Biometry and Informatics, University Hospital Heidelberg, Heidelberg, Germany
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13
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Kaufmann D, Theriot JJ, Zyuzin J, Service CA, Chang JC, Tang YT, Bogdanov VB, Multon S, Schoenen J, Ju YS, Brennan KC. Heterogeneous incidence and propagation of spreading depolarizations. J Cereb Blood Flow Metab 2017; 37:1748-1762. [PMID: 27562866 PMCID: PMC5435294 DOI: 10.1177/0271678x16659496] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/16/2016] [Revised: 05/27/2016] [Accepted: 06/06/2016] [Indexed: 12/17/2022]
Abstract
Spreading depolarizations are implicated in a diverse set of neurologic diseases. They are unusual forms of nervous system activity in that they propagate very slowly and approximately concentrically, apparently not respecting the anatomic, synaptic, functional, or vascular architecture of the brain. However, there is evidence that spreading depolarizations are not truly concentric, isotropic, or homogeneous, either in space or in time. Here we present evidence from KCl-induced spreading depolarizations, in mouse and rat, in vivo and in vitro, showing the great variability that these depolarizations can exhibit. This variability can help inform the mechanistic understanding of spreading depolarizations, and it has implications for their phenomenology in neurologic disease.
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Affiliation(s)
- Dan Kaufmann
- Department of Neurology, University of Utah, Salt Lake City, UT, USA
| | - Jeremy J Theriot
- Department of Neurology, University of Utah, Salt Lake City, UT, USA
- Department of Neurology, University of California Los Angeles, Los Angeles, CA, USA
| | - Jekaterina Zyuzin
- Department of Neurology, University of California Los Angeles, Los Angeles, CA, USA
| | - C Austin Service
- Department of Neurology, University of Utah, Salt Lake City, UT, USA
| | - Joshua C Chang
- Rehabilitation Medicine Department, Mark O. Hatfield Clinical Research Center, National Institutes of Health, Bethesda, MD, USA
- Mathematical Biosciences Institute, The Ohio State University, Columbus, OH, USA
| | - Y Tanye Tang
- Department of Mechanical and Aerospace Engineering, University of California Los Angeles, Los Angeles, CA, USA
| | - Vladimir B Bogdanov
- Department of Neurology, University of Utah, Salt Lake City, UT, USA
- Department of Neurology, University of Liège, Liège, Belgium
| | - Sylvie Multon
- Department of Neurology, University of Liège, Liège, Belgium
| | - Jean Schoenen
- Department of Neurology, University of Liège, Liège, Belgium
| | - Y Sungtaek Ju
- Department of Mechanical and Aerospace Engineering, University of California Los Angeles, Los Angeles, CA, USA
| | - KC Brennan
- Department of Neurology, University of Utah, Salt Lake City, UT, USA
- Department of Neurology, University of California Los Angeles, Los Angeles, CA, USA
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14
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Abstract
Background Hypoxia causes secondary headaches such as high-altitude headache (HAH) and headache due to acute mountain sickness. These secondary headaches mimic primary headaches such as migraine, which suggests a common link. We review and discuss the possible role of hypoxia in migraine and cluster headache. Methods This narrative review investigates the current level of knowledge on the relation of hypoxia in migraine and cluster headache based on epidemiological and experimental studies. Findings Epidemiological studies suggest that living in high-altitude areas increases the risk of migraine and especially migraine with aura. Human provocation models show that hypoxia provokes migraine with and without aura, whereas cluster headache has not been reliably induced by hypoxia. Possible pathophysiological mechanisms include hypoxia-induced release of nitric oxide and calcitonin gene-related peptide, cortical spreading depression and leakage of the blood-brain barrier. Conclusion There is a possible link between hypoxia and migraine and maybe cluster headache, but the exact mechanism is currently unknown. Provocation models of hypoxia have yielded interesting results suggesting a novel approach to study in depth the mechanism underlying hypoxia and primary headaches.
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Affiliation(s)
- Josefine Britze
- Danish Headache Center and Department of Neurology, Rigshospitalet Glostrup, Faculty of Health and Medical Sciences, University of Copenhagen, Denmark
| | - Nanna Arngrim
- Danish Headache Center and Department of Neurology, Rigshospitalet Glostrup, Faculty of Health and Medical Sciences, University of Copenhagen, Denmark
| | - Henrik Winther Schytz
- Danish Headache Center and Department of Neurology, Rigshospitalet Glostrup, Faculty of Health and Medical Sciences, University of Copenhagen, Denmark
| | - Messoud Ashina
- Danish Headache Center and Department of Neurology, Rigshospitalet Glostrup, Faculty of Health and Medical Sciences, University of Copenhagen, Denmark
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15
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Yao X, Smith AJ, Jin BJ, Zador Z, Manley GT, Verkman A. Aquaporin-4 regulates the velocity and frequency of cortical spreading depression in mice. Glia 2015; 63:1860-9. [PMID: 25944186 PMCID: PMC4743984 DOI: 10.1002/glia.22853] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2014] [Revised: 03/20/2015] [Accepted: 04/15/2015] [Indexed: 01/02/2023]
Abstract
The astrocyte water channel aquaporin-4 (AQP4) regulates extracellular space (ECS) K(+) concentration ([K(+)]e) and volume dynamics following neuronal activation. Here, we investigated how AQP4-mediated changes in [K(+)]e and ECS volume affect the velocity, frequency, and amplitude of cortical spreading depression (CSD) depolarizations produced by surface KCl application in wild-type (AQP4(+/+)) and AQP4-deficient (AQP4(-/-)) mice. In contrast to initial expectations, both the velocity and the frequency of CSD were significantly reduced in AQP4(-/-) mice when compared with AQP4(+/+) mice, by 22% and 32%, respectively. Measurement of [K(+)]e with K(+)-selective microelectrodes demonstrated an increase to ∼35 mM during spreading depolarizations in both AQP4(+/+) and AQP4(-/-) mice, but the rates of [K(+)]e increase (3.5 vs. 1.5 mM/s) and reuptake (t1/2 33 vs. 61 s) were significantly reduced in AQP4(-/-) mice. ECS volume fraction measured by tetramethylammonium iontophoresis was greatly reduced during depolarizations from 0.18 to 0.053 in AQP4(+/+) mice, and 0.23 to 0.063 in AQP4(-/-) mice. Analysis of the experimental data using a mathematical model of CSD propagation suggested that the reduced velocity of CSD depolarizations in AQP4(-/-) mice was primarily a consequence of the slowed increase in [K(+)]e during neuronal depolarization. These results demonstrate that AQP4 effects on [K(+)]e and ECS volume dynamics accelerate CSD propagation.
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Affiliation(s)
- Xiaoming Yao
- Department of Medicine and Physiology, University of California, San Francisco, CA 94143, USA
- Department of Neurological Surgery, University of California, San Francisco, CA 94143, USA
| | - Alex J. Smith
- Department of Medicine and Physiology, University of California, San Francisco, CA 94143, USA
| | - Byung-Ju Jin
- Department of Medicine and Physiology, University of California, San Francisco, CA 94143, USA
| | - Zsolt Zador
- Department of Neurological Surgery, University of California, San Francisco, CA 94143, USA
| | - Geoffrey T. Manley
- Department of Neurological Surgery, University of California, San Francisco, CA 94143, USA
| | - A.S. Verkman
- Department of Medicine and Physiology, University of California, San Francisco, CA 94143, USA
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16
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Karunasinghe RN, Lipski J. Oxygen and glucose deprivation (OGD)-induced spreading depression in the Substantia Nigra. Brain Res 2013; 1527:209-21. [PMID: 23796781 DOI: 10.1016/j.brainres.2013.06.016] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2013] [Accepted: 06/14/2013] [Indexed: 01/07/2023]
Abstract
Spreading depression (SD) is a profound depolarization of neurons and glia that propagates in a wave-like manner across susceptible brain regions, and can develop during periods of compromised cellular energy such as ischemia, when it influences the severity of acute neuronal damage. Although SD has been well characterized in the cerebral cortex and hippocampus, little is known of this event in the Substantia Nigra (SN), a brainstem nucleus engaged in motor control and reward-related behavior. Transverse brain slices (250 μm; P21-23 rats) containing the SN were subject to oxygen and glucose deprivation (OGD) tests, modeling brain ischemia. SD developed in lateral aspects of the SN within 3.3±0.2 min of OGD onset, and spread through the Substantia Nigra pars reticulata (SNr), as indicated by fast-occurring and propagating increased tissue light transmittance and negative shift of extracellular DC potential. These events were associated with profound mitochondrial membrane depolarization (ΔΨm) throughout the SN, as demonstrated by increased Rhodamine 123 fluorescence. Extracellular recordings from individual SNr neurons indicated rapid depolarization followed by depolarizing block, while dopaminergic neurons in the Substantia Nigra pars compacta (SNc) showed inhibition of firing associated with hyperpolarization. SD evoked in the SNr was similar to OGD-induced SD in the CA1 region in hippocampal slices. In the hippocampus, SD also developed during anoxia or aglycemia alone (associated with less profound ΔΨm than OGD), while these conditions rarely led to SD in the SNr. Our results demonstrate that OGD consistently evokes SD in the SN, and that this phenomenon only involves the SNr. It remains to be established whether nigral SD contributes to neuronal damage associated with a sudden-onset form of Parkinson's disease known as 'vascular parkinsonism'.
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Affiliation(s)
- Rashika N Karunasinghe
- Department of Physiology and Centre for Brain Research, Faculty of Medical and Health Sciences, University of Auckland, Auckland 92019, New Zealand
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17
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Pál I, Nyitrai G, Kardos J, Héja L. Neuronal and astroglial correlates underlying spatiotemporal intrinsic optical signal in the rat hippocampal slice. PLoS One 2013; 8:e57694. [PMID: 23469218 PMCID: PMC3585794 DOI: 10.1371/journal.pone.0057694] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2012] [Accepted: 01/28/2013] [Indexed: 11/24/2022] Open
Abstract
Widely used for mapping afferent activated brain areas in vivo, the label-free intrinsic optical signal (IOS) is mainly ascribed to blood volume changes subsequent to glial glutamate uptake. By contrast, IOS imaged in vitro is generally attributed to neuronal and glial cell swelling, however the relative contribution of different cell types and molecular players remained largely unknown. We characterized IOS to Schaffer collateral stimulation in the rat hippocampal slice using a 464-element photodiode-array device that enables IOS monitoring at 0.6 ms time-resolution in combination with simultaneous field potential recordings. We used brief half-maximal stimuli by applying a medium intensity 50 Volt-stimulus train within 50 ms (20 Hz). IOS was primarily observed in the str. pyramidale and proximal region of the str. radiatum of the hippocampus. It was eliminated by tetrodotoxin blockade of voltage-gated Na(+) channels and was significantly enhanced by suppressing inhibitory signaling with gamma-aminobutyric acid(A) receptor antagonist picrotoxin. We found that IOS was predominantly initiated by postsynaptic Glu receptor activation and progressed by the activation of astroglial Glu transporters and Mg(2+)-independent astroglial N-methyl-D-aspartate receptors. Under control conditions, role for neuronal K(+)/Cl(-) cotransporter KCC2, but not for glial Na(+)/K(+)/Cl(-) cotransporter NKCC1 was observed. Slight enhancement and inhibition of IOS through non-specific Cl(-) and volume-regulated anion channels, respectively, were also depicted. High-frequency IOS imaging, evoked by brief afferent stimulation in brain slices provide a new paradigm for studying mechanisms underlying IOS genesis. Major players disclosed this way imply that spatiotemporal IOS reflects glutamatergic neuronal activation and astroglial response, as observed within the hippocampus. Our model may help to better interpret in vivo IOS and support diagnosis in the future.
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Affiliation(s)
- Ildikó Pál
- Department of Functional Pharmacology, Institute of Molecular Pharmacology, Research Centre for Natural Sciences, Hungarian Academy of Sciences, Budapest, Hungary.
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