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Spreading depolarization

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https://www.readbyqxmd.com/read/28600353/age-or-ischemia-uncouples-the-blood-flow-response-tissue-acidosis-and-the-direct-current-potential-signature-of-spreading-depolarization-in-the-rat-brain
#1
Ákos Menyhárt, Dániel Zölei-Szénási, Tamás Puskás, Péter Makra, Ferenc Bari, Eszter Farkas
Spreading depolarization (SD) events contribute to lesion maturation in the acutely injured human brain. Neurodegeneration related to SD is thought to be caused by the insufficiency of the cerebral blood flow (CBF) response; yet, the mediators of the CBF response, or their deficiency in the aged or ischemic cerebral cortex remain the target of intensive research. Here we postulate that tissue pH effectively modulates the magnitude of hyperemia in response to SD, which coupling is prone to be dysfunctional in the aged or ischemic cerebral cortex...
June 9, 2017: American Journal of Physiology. Heart and Circulatory Physiology
https://www.readbyqxmd.com/read/28535487/nerve-excitability-changes-related-to-muscle-weakness-in-chronic-progressive-external-ophthalmoplegia
#2
Antoine Gueguen, Claude Jardel, Marc Polivka, S Veronica Tan, Françoise Gray, Catherine Vignal, Anne Lombès, Olivier Gout, Hugh Bostock
OBJECTIVE: To explore potential spreading to peripheral nerves of the mitochondrial dysfunction in chronic progressive external ophthalmoplegia (CPEO) by assessing axonal excitability. METHODS: CPEO patients (n=13) with large size deletion of mitochondrial DNA and matching healthy controls (n=22) were included in a case-control study. Muscle strength was quantified using MRC sum-score and used to define two groups of patients: CPEO-weak and CPEO-normal (normal strength)...
July 2017: Clinical Neurophysiology: Official Journal of the International Federation of Clinical Neurophysiology
https://www.readbyqxmd.com/read/28507142/quantitative-assessment-of-passive-electrical-properties-of-the-cardiac-t-tubular-system-by-frap-microscopy
#3
M Scardigli, C Crocini, C Ferrantini, T Gabbrielli, L Silvestri, R Coppini, C Tesi, E A Rog-Zielinska, P Kohl, E Cerbai, C Poggesi, F S Pavone, L Sacconi
Well-coordinated activation of all cardiomyocytes must occur on every heartbeat. At the cell level, a complex network of sarcolemmal invaginations, called the transverse-axial tubular system (TATS), propagates membrane potential changes to the cell core, ensuring synchronous and uniform excitation-contraction coupling. Although myocardial conduction of excitation has been widely described, the electrical properties of the TATS remain mostly unknown. Here, we exploit the formal analogy between diffusion and electrical conductivity to link the latter with the diffusional properties of TATS...
May 30, 2017: Proceedings of the National Academy of Sciences of the United States of America
https://www.readbyqxmd.com/read/28482157/enhancing-continuous-online-microdialysis-using-dexamethasone-measurement-of-dynamic-neurometabolic-changes-during-spreading-depolarization
#4
Erika L Varner, Chi Leng Leong, Andrea Jaquins-Gerstl, Kathryn M Nesbitt, Martyn G Boutelle, Adrian Charles Michael
Microdialysis is well established in chemical neuroscience as a mainstay technology for real time intracranial chemical monitoring in both animal models and human patients. Evidence shows that microdialysis can be enhanced by mitigating the penetration injury caused during the insertion of microdialysis probes into brain tissue. Herein, we show that retrodialysis of dexamethasone in the rat cortex enhances the microdialysis detection of K+ and glucose transients induced by spreading depolarization. Without dexamethasone, quantification of glucose transients was unreliable by 5 days after probe insertion...
May 8, 2017: ACS Chemical Neuroscience
https://www.readbyqxmd.com/read/28479338/effects-of-experimental-traumatic-brain-injury-and-impaired-glutamate-transport-on-cortical-spreading-depression
#5
Mahshid Sadat Hosseini-Zare, Feng Gu, Ahmad Abdulla, Simon Powell, Jokūbas Žiburkus
Cortical spreading depression (CSD) is associated with traumatic brain injury (TBI), stroke, migraines, and seizures. Typically, following TBIs and other insults, neuronal excitability in and around the area of the injury is affected, with reported increases in local glutamate signaling. Astrocytic glutamate transporters are critical for precise regulation of the extracellular glutamate availability. However, it remains unclear how impaired astrocytic glutamate transport or an acute TBI affect characteristics of the CSD...
May 4, 2017: Experimental Neurology
https://www.readbyqxmd.com/read/28445178/familial-hemiplegic-migraine-with-asymmetric-encephalopathy-secondary-to-atp1a2-mutation-a-case-series
#6
Olwen C Murphy, Aine Merwick, Olivia OʼMahony, Aisling M Ryan, Brian McNamara
INTRODUCTION: Familial hemiplegic migraine (FHM) is a genetic disease with a variable clinical phenotype. The imaging and electroencephalogram (EEG) correlates of FHM are not well described. CASE SERIES: We describe a case series of five young women aged 12 to 32 years. Each case presented with headache, encephalopathy, and hemiparesis of varying severity. One patient developed seizures. All patients improved spontaneously. INVESTIGATIONS: Asymmetric slow-wave activity was seen on electroencephalogram in each case...
April 25, 2017: Journal of Clinical Neurophysiology: Official Publication of the American Electroencephalographic Society
https://www.readbyqxmd.com/read/28442781/spreading-depolarization-remarkably-exacerbates-ischemia-induced-tissue-acidosis-in-the-young-and-aged-rat-brain
#7
Ákos Menyhárt, Dániel Zölei-Szénási, Tamás Puskás, Péter Makra, M Tóth Orsolya, Borbála É Szepes, Réka Tóth, Orsolya Ivánkovits-Kiss, Tihomir P Obrenovitch, Ferenc Bari, Eszter Farkas
Spreading depolarizations (SDs) occur spontaneously in the cerebral cortex of subarachnoid hemorrhage, stroke or traumatic brain injury patients. Accumulating evidence prove that SDs exacerbate focal ischemic injury by converting zones of the viable but non-functional ischemic penumbra to the core region beyond rescue. Yet the SD-related mechanisms to mediate neurodegeneration remain poorly understood. Here we show in the cerebral cortex of isoflurane-anesthetized, young and old laboratory rats, that SDs propagating under ischemic penumbra-like conditions decrease intra and- extracellular tissue pH transiently to levels, which have been recognized to cause tissue damage...
April 25, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28436257/brain-temperature-but-not-core-temperature-increases-during-spreading-depolarizations-in-patients-with-spontaneous-intracerebral-hemorrhage
#8
Alois J Schiefecker, Mario Kofler, Max Gaasch, Ronny Beer, Iris Unterberger, Bettina Pfausler, Gregor Broessner, Peter Lackner, Paul Rhomberg, Elke Gizewski, Werner O Hackl, Miriam Mulino, Martin Ortler, Claudius Thome, Erich Schmutzhard, Raimund Helbok
Spreading depolarizations (SDs) are highly active metabolic events, commonly occur in patients with intracerebral hemorrhage (ICH) and may be triggered by fever. We investigated the dynamics of brain-temperature (Tbrain) and core-temperature (Tcore) relative to the occurrence of SDs. Twenty consecutive comatose ICH patients with multimodal electrocorticograpy (ECoG) and Tbrain monitoring of the perihematomal area were prospectively enrolled. Clusters of SDs were defined as ≥2 SDs/h. Generalized estimating equations were used for statistical calculations...
January 1, 2017: Journal of Cerebral Blood Flow and Metabolism
https://www.readbyqxmd.com/read/28430869/inhibition-of-the-p2x7-panx1-complex-suppresses-spreading-depolarization-and-neuroinflammation
#9
Shih-Pin Chen, Tao Qin, Jessica L Seidel, Yi Zheng, Matthias Eikermann, Michel D Ferrari, Arn M J M van den Maagdenberg, Michael A Moskowitz, Cenk Ayata, Katharina Eikermann-Haerter
Spreading depolarization is a wave of neuronal and glial depolarization. Within minutes after spreading depolarization, the neuronal hemichannel pannexin 1 (PANX1) opens and forms a pore complex with the ligand-gated cation channel P2X7, allowing the release of excitatory neurotransmitters to sustain spreading depolarization and activate neuroinflammation. Here, we explore the hypothesis that the P2X7-PANX1 pore complex is a critical determinant of spreading depolarization susceptibility with important consequences for neuroinflammation and trigeminovascular activation...
June 1, 2017: Brain: a Journal of Neurology
https://www.readbyqxmd.com/read/28350195/standard-sampling-microdialysis-and-spreading-depolarizations-in-patients-with-malignant-hemispheric-stroke
#10
Alexandra Pinczolits, Anna Zdunczyk, Nora F Dengler, Nils Hecht, Christina M Kowoll, Christian Dohmen, Rudolf Graf, Maren Kl Winkler, Sebastian Major, Jed A Hartings, Jens P Dreier, Peter Vajkoczy, Johannes Woitzik
Spreading depolarizations (SD) occur in high frequency in patients with malignant hemispheric stroke (MHS). Experimentally, SDs cause marked increases in glutamate and lactate, whereas glucose decreases. Here, we studied extracellular brain glutamate, glucose, lactate, pyruvate and the lactate/pyruvate ratio in relationship to SDs after MHS. We inserted two microdialysis probes in peri-infarct tissue at 5 and 15 mm to the infarct in close proximity to a subdural electrode strip. During 2356.6 monitoring hours, electrocorticography (ECoG) revealed 697 SDs in 16 of 18 patients...
May 2017: Journal of Cerebral Blood Flow and Metabolism
https://www.readbyqxmd.com/read/28321943/development-of-3-d-intramural-and-surface-potentials-in-the-lv-microstructural-basis-of-preferential-transmural-conduction
#11
Bryan J Caldwell, Mark L Trew, Ian J Legrice, Bruce H Smaill
INTRODUCTION: Extracellular potentials measured on the heart surfaces are used to infer events that originate deep within the heart wall. We have reconstructed intramural potentials in three dimensions for the first time, and compare these with epicardial and endocardial surface potentials and cardiac microstructure. METHODS AND RESULTS: Extracellular potentials from intramural point stimulation were measured from a high density 3-D electrode array in the in vivo pig LV...
June 2017: Journal of Cardiovascular Electrophysiology
https://www.readbyqxmd.com/read/28271496/genetics-of-migraine-insights-into-the-molecular-basis-of-migraine-disorders
#12
REVIEW
Heidi G Sutherland, Lyn R Griffiths
Migraine is a complex, debilitating neurovascular disorder, typically characterized by recurring, incapacitating attacks of severe headache often accompanied by nausea and neurological disturbances. It has a strong genetic basis demonstrated by rare migraine disorders caused by mutations in single genes (monogenic), as well as familial clustering of common migraine which is associated with polymorphisms in many genes (polygenic). Hemiplegic migraine is a dominantly inherited, severe form of migraine with associated motor weakness...
April 2017: Headache
https://www.readbyqxmd.com/read/28269735/polysilicon-based-flexible-temperature-sensor-for-high-spatial-resolution-brain-temperature-monitoring
#13
Zhizhen Wu, Chunyan Li, Jed Hartings, Raj K Narayan, Chong Ahn
In this paper, we present a flexible temperature sensor with ultra-small polysilicon thermistors for brain temperature monitoring. In vitro sensitivity, resolution, thermal hysteresis and long term stability tests were performed. Temperature coefficient of resistance (TCR) of -0.0031/ °C and resolution of 0.1 °C were obtained for the sensor. Thermal hysteresis for temperature range of 30~45 °C was less than 0.1 °C. With silicon nitride as the passivation layer, the temperature sensor showed a drift within 0...
August 2016: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
https://www.readbyqxmd.com/read/28256093/a-quantitative-structural-and-morphometric-analysis-of-the-purkinje-network-and-the-purkinje-myocardial-junctions-in-pig-hearts
#14
V Garcia-Bustos, R Sebastian, M Izquierdo, P Molina, F J Chorro, A Ruiz-Sauri
The morpho-functional properties of the distal section of the cardiac Purkinje network (PN) and the Purkinje-myocardial junctions (PMJs) are fundamental to understanding the sequence of electrical activation in the heart. The overall structure of the system has already been described, and several computational models have been developed to gain insight into its involvement in cardiac arrhythmias or its interaction with implantable devices, such as pacemakers. However, anatomical descriptions of the PN in the literature have not enabled enough improvements in the accuracy of anatomical-based electrophysiological simulations of the PN in 3D hearts models...
March 3, 2017: Journal of Anatomy
https://www.readbyqxmd.com/read/28240389/increased-intrinsic-brain-connectivity-between-pons-and-somatosensory-cortex-during-attacks-of-migraine-with-aura
#15
Anders Hougaard, Faisal Mohammad Amin, Henrik B W Larsson, Egill Rostrup, Messoud Ashina
The neurological disturbances of migraine aura are caused by transient cortical dysfunction due to waves of spreading depolarization that disrupt neuronal signaling. The effects of these cortical events on intrinsic brain connectivity during attacks of migraine aura have not previously been investigated. Studies of spontaneous migraine attacks are notoriously challenging due to their unpredictable nature and patient discomfort. We investigated 16 migraine patients with visual aura during attacks and in the attack-free state using resting state fMRI...
May 2017: Human Brain Mapping
https://www.readbyqxmd.com/read/28228266/rapid-state-dependent-alteration-in-kv3-channel-availability-drives-flexible-synaptic-signaling-dependent-on-somatic-subthreshold-depolarization
#16
Matthew J M Rowan, Jason M Christie
In many neurons, subthreshold depolarization in the soma can transiently increase action-potential (AP)-evoked neurotransmission via analog-to-digital facilitation. The mechanisms underlying this form of short-term synaptic plasticity are unclear, in part, due to the relative inaccessibility of the axon to direct physiological interrogation. Using voltage imaging and patch-clamp recording from presynaptic boutons of cerebellar stellate interneurons, we observed that depolarizing somatic potentials readily spread into the axon, resulting in AP broadening, increased spike-evoked Ca(2+) entry, and enhanced neurotransmission strength...
February 21, 2017: Cell Reports
https://www.readbyqxmd.com/read/28227999/polysilicon-based-flexible-temperature-sensor-for-high-spatial-resolution-brain-temperature-monitoring
#17
Zhizhen Wu, Chunyan Li, Jed Hartings, Raj K Narayan, Chong Ahn, Zhizhen Wu, Chunyan Li, Jed Hartings, Raj K Narayan, Chong Ahn, Zhizhen Wu, Chunyan Li, Chong Ahn, Jed Hartings, Raj K Narayan
In this paper, we present a flexible temperature sensor with ultra-small polysilicon thermistors for brain temperature monitoring. In vitro sensitivity, resolution, thermal hysteresis and long term stability tests were performed. Temperature coefficient of resistance (TCR) of -0.0031/ °C and resolution of 0.1 °C were obtained for the sensor. Thermal hysteresis for temperature range of 30~45 °C was less than 0.1 °C. With silicon nitride as the passivation layer, the temperature sensor showed a drift within 0...
August 2016: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
https://www.readbyqxmd.com/read/28226410/patient-specific-computational-modeling-of-cortical-spreading-depression-via-diffusion-tensor-imaging
#18
Julia M Kroos, Isabella Marinelli, Ibai Diez, Jesus M Cortes, Sebastiano Stramaglia, Luca Gerardo-Giorda
Cortical Spreading Depression (CSD), a depolarization wave originating in the visual cortex and traveling towards the frontal lobe, is commonly accepted as a correlate of migraine visual aura. As of today, little is known about the mechanisms that can trigger or stop such phenomenon. However, the complex and highly individual characteristics of the brain cortex suggest that the geometry might have a significant impact in supporting or contrasting the propagation of CSD. Accurate patient-specific computational models are fundamental to cope with the high variability in cortical geometries among individuals, but also with the conduction anisotropy induced in a given cortex by the complex neuronal organisation in the grey matter...
February 22, 2017: International Journal for Numerical Methods in Biomedical Engineering
https://www.readbyqxmd.com/read/28223494/exploitation-of-the-spreading-depolarization-induced-cytotoxic-edema-for-high-resolution-3d-mapping-of-its-heterogeneous-propagation-paths
#19
Jens P Dreier, Clemens Reiffurth
No abstract text is available yet for this article.
February 28, 2017: Proceedings of the National Academy of Sciences of the United States of America
https://www.readbyqxmd.com/read/28215745/astrocyte-transport-of-glutamate-and-neuronal-activity-reciprocally-modulate-tau-pathology-in-drosophila
#20
Jason G Kilian, Heng-Wei Hsu, Kenneth Mata, Fred W Wolf, Masashi Kitazawa
Abnormal buildup of the microtubule associated protein tau is a major pathological hallmark of Alzheimer's disease (AD) and various tauopathies. The mechanisms by which pathological tau accumulates and spreads throughout the brain remain largely unknown. Previously, we demonstrated that a restoration of the major astrocytic glutamate transporter, GLT1, ameliorated a buildup of tau pathology and rescued cognition in a mouse model of AD. We hypothesized that aberrant extracellular glutamate and abnormal neuronal excitatory activities promoted tau pathology...
February 16, 2017: Neuroscience
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