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Spreading depolarization

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https://www.readbyqxmd.com/read/28094974/monitoring-dopamine-responses-to-potassium-ion-and-nomifensine-by-in-vivo-microdialysis-with-online-liquid-chromatography-at-one-minute-resolution
#1
Khanh Thieu Ngo, Erika L Varner, Adrian Charles Michael, Stephen G Weber
Recently, our laboratory has demonstrated the technical feasibility of monitoring dopamine at one-min temporal resolution with microdialysis and online liquid chromatography. Here, we monitor dopamine in the rat striatum during local delivery of potassium ion and nomifensine in awake-behaving rats. Microdialysis probes were implanted and dopamine was monitored one or four Days later under basal conditions, during 10-min applications of 60 mM or 100 mM K+, and during 15-min applications of 10 µM nomifensine: K+ and nomifensine were delivered locally by adding them to the microdialysis perfusion fluid...
January 17, 2017: ACS Chemical Neuroscience
https://www.readbyqxmd.com/read/28088802/interplay-between-cortical-spreading-depolarization-and-seizures
#2
Daniel R Kramer, Tatsuhiro Fujii, Ifije Ohiorhenuan, Charles Y Liu
Cortical spreading depolarization (CSD) is an electrophysiologic phenomenon found mostly in the setting of neurologic injury resulting in the disturbance of ion homeostasis and leading to changes in the local vascular response. The bioelectric etiology of CSD shares similarities to those in epileptic disorders, yet the relationship between seizures and CSD is unclear, with several studies observing cortical depression before, during, and after seizure activity, thus obscuring our understanding of whether CSD activity potentiates or limits seizures and vice versa...
January 14, 2017: Stereotactic and Functional Neurosurgery
https://www.readbyqxmd.com/read/28086931/the-release-and-trans-synaptic-transmission-of-tau-via-exosomes
#3
Yipeng Wang, Varun Balaji, Senthilvelrajan Kaniyappan, Lars Krüger, Stephan Irsen, Katharina Tepper, RamReddy Chandupatla, Walter Maetzler, Anja Schneider, Eckhard Mandelkow, Eva-Maria Mandelkow
BACKGROUND: Tau pathology in AD spreads in a hierarchical pattern, whereby it first appears in the entorhinal cortex, then spreads to the hippocampus and later to the surrounding areas. Based on this sequential appearance, AD can be classified into six stages ("Braak stages"). The mechanisms and agents underlying the progression of Tau pathology are a matter of debate. Emerging evidence indicates that the propagation of Tau pathology may be due to the transmission of Tau protein, but the underlying pathways and Tau species are not well understood...
January 13, 2017: Molecular Neurodegeneration
https://www.readbyqxmd.com/read/28065672/monitoring-microvascular-perfusion-variations-with-laser-speckle-contrast-imaging-using-a-view-based-temporal-template-method
#4
Mohammad Zaheer Ansari, Eun-Jeung Kang, Mioara D Manole, Jens P Dreier, Anne Humeau-Heurtier
PURPOSE: Laser speckle contrast imaging (LSCI) continues to gain an increased interest in clinical and research studies to monitor microvascular perfusion. Due to its high spatial and temporal resolutions, LSCI may lead to a large amount of data. The analysis of such data, as well as the determination of the regions where the perfusion varies, can become a lengthy and tedious task. We propose here to analyze if a view-based temporal template method, the motion history image (MHI) algorithm, may be of use in detecting the perfusion variations locations...
January 5, 2017: Microvascular Research
https://www.readbyqxmd.com/read/28028801/transcranial-magnetic-stimulation-basic-principles-and-clinical-applications-in-migraine
#5
Anthony T Barker, Kevin Shields
PURPOSE: Transcranial magnetic stimulation (TMS) is a neurophysiological technique with a long established pedigree of safety, tolerability, and efficacy. Initially TMS was used to study the function of the cerebral cortex, but it has now become a treatment for migraine, one of the most common and debilitating neurological conditions. In this review we discuss the scientific background and development of the technique. We explore its application for the treatment of migraine and ponder the possible mechanisms of action in this most common neurological condition...
December 28, 2016: Headache
https://www.readbyqxmd.com/read/28028144/valproate-reduces-delayed-brain-injury-in-a-rat-model-of-subarachnoid-hemorrhage
#6
Arend M Hamming, Annette van der Toorn, Umesh S Rudrapatna, Lisha Ma, Hine J A van Os, Michel D Ferrari, Arn M J M van den Maagdenberg, Erik van Zwet, Katherine Poinsatte, Ann M Stowe, Rick M Dijkhuizen, Marieke J H Wermer
BACKGROUND AND PURPOSE: Spreading depolarizations (SDs) may contribute to delayed cerebral ischemia after subarachnoid hemorrhage (SAH). We tested whether SD-inhibitor valproate reduces brain injury in an SAH rat model with and without experimental SD induction. METHODS: Rats were randomized in a 2×2 design and pretreated with valproate (200 mg/kg) or vehicle for 4 weeks. SAH was induced by endovascular puncture of the right internal carotid bifurcation. One day post-SAH, brain tissue damage was measured with T2-weighted magnetic resonance imaging, followed by cortical application of 1 mol/L KCl (to induce SDs) or NaCl (no SDs)...
December 27, 2016: Stroke; a Journal of Cerebral Circulation
https://www.readbyqxmd.com/read/27987215/cortical-spreading-depression-csd-preconditioning-mediates-neuroprotection-against-ischemic-stroke-by-inducing-amp-activated-protein-kinase-dependent-autophagy-in-a-rat-cerebral-ischemic-reperfusion-injury-model
#7
P P Shen, S Hou, M Q Zhu, M M Zhao, Yibing Ouyang, J C Feng
Cortical spreading depression (CSD), based on its similarities with peri-infarct depolarization (PID), is an ideal model for investigating transformation from the ischemic penumbra to infarct core. However, the underlying mechanisms remain unclear. To our knowledge, this is the first study to use a middle cerebral artery occlusion (MCAO) ischemic-reperfusion (I/R) injury model to determine whether AMP-activated protein kinase (AMPK)-dependent autophagy contributes to the neuroprotection of CSD preconditioning in rat cortex...
December 17, 2016: Journal of Neurochemistry
https://www.readbyqxmd.com/read/27924865/quantum-error-correction-protects-quantum-search-algorithms-against-decoherence
#8
Panagiotis Botsinis, Zunaira Babar, Dimitrios Alanis, Daryus Chandra, Hung Nguyen, Soon Xin Ng, Lajos Hanzo
When quantum computing becomes a wide-spread commercial reality, Quantum Search Algorithms (QSA) and especially Grover's QSA will inevitably be one of their main applications, constituting their cornerstone. Most of the literature assumes that the quantum circuits are free from decoherence. Practically, decoherence will remain unavoidable as is the Gaussian noise of classic circuits imposed by the Brownian motion of electrons, hence it may have to be mitigated. In this contribution, we investigate the effect of quantum noise on the performance of QSAs, in terms of their success probability as a function of the database size to be searched, when decoherence is modelled by depolarizing channels' deleterious effects imposed on the quantum gates...
December 7, 2016: Scientific Reports
https://www.readbyqxmd.com/read/27919769/transcriptomic-changes-in-rat-cortex-and-brainstem-after-cortical-spreading-depression-with-or-without-pre-treatment-with-migraine-prophylactic-drugs
#9
Cèlia Sintas, Noèlia Fernàndez-Castillo, Marta Vila-Pueyo, Patricia Pozo-Rosich, Alfons Macaya, Bru Cormand
: Migraine with aura is a subtype of migraine consisting of neurological disturbances that usually precede headache. Cortical spreading depression (CSD) is the likely pathophysiological correlate of the aura phase of migraine, found in common and rare forms of migraine, such as familial hemiplegic migraine (FHM). CSD is a depolarization wave that propagates across the cerebral gray matter transiently suppressing neuronal activity. Prophylactic treatments for migraine, such as topiramate (TPM) or valproate (VPA), reduce the number of CSD events...
December 2, 2016: Journal of Pain: Official Journal of the American Pain Society
https://www.readbyqxmd.com/read/27826106/differential-spread-of-anoxic-depolarization-contributes-to-the-pattern-of-neuronal-injury-after-oxygen-and-glucose-deprivation-ogd-in-the-substantia-nigra-in-rat-brain-slices
#10
Rashika N Karunasinghe, Angus C Grey, Ravindra Telang, Srdjan M Vlajkovic, Janusz Lipski
Anoxic depolarization (AD) is an acute event evoked by brain ischemia, involving a profound loss of cell membrane potential and swelling that spreads over susceptible parts of the gray matter. Its occurrence is a strong predictor of the severity of neuronal injury. Little is known about this event in the Substantia Nigra, a midbrain nucleus critical for motor control. We tested the effects of oxygen and glucose deprivation (OGD), an in vitro model of brain ischemia, in rat midbrain slices. AD developed within 4min from OGD onset and spread in the Substantia Nigra pars reticulata (SNr), but not through the Substantia Nigra pars compacta (SNc)...
January 6, 2017: Neuroscience
https://www.readbyqxmd.com/read/27788776/rsv-specific-anti-viral-immunity-is-disrupted-by-chronic-ethanol-consumption
#11
Kristi J Warren, Samantha M Simet, Jacqueline A Pavlik, Jane M DeVasure, Joseph H Sisson, Jill A Poole, Todd A Wyatt
Alcohol-use disorders (AUD) persist in the United States and are heavily associated with an increased susceptibility to respiratory viral infections. Respiratory syncytial virus (RSV) in particular has received attention as a viral pathogen commonly detected in children and immune-compromised populations (elderly, asthmatics), yet more recently was recognized as an important viral pathogen in young adults. Our study evaluated the exacerbation of RSV-associated illness in mice that chronically consumed alcohol for 6 weeks prior to infection...
September 2016: Alcohol
https://www.readbyqxmd.com/read/27737684/management-of-delayed-cerebral-ischemia-after-subarachnoid-hemorrhage
#12
REVIEW
Charles L Francoeur, Stephan A Mayer
For patients who survive the initial bleeding event of a ruptured brain aneurysm, delayed cerebral ischemia (DCI) is one of the most important causes of mortality and poor neurological outcome. New insights in the last decade have led to an important paradigm shift in the understanding of DCI pathogenesis. Large-vessel cerebral vasospasm has been challenged as the sole causal mechanism; new hypotheses now focus on the early brain injury, microcirculatory dysfunction, impaired autoregulation, and spreading depolarization...
October 14, 2016: Critical Care: the Official Journal of the Critical Care Forum
https://www.readbyqxmd.com/read/27730322/effects-of-glia-in-a-triphasic-continuum-model-of-cortical-spreading-depression
#13
Rosemary O'Connell, Yoichiro Mori
Cortical spreading depression (SD) is a spreading disruption in brain ionic homeostasis during which neurons experience complete and prolonged depolarizations. SD is generally believed to be the physiological substrate of migraine aura and is associated with many other brain pathologies. Here, we perform simulations with a model of SD treating brain tissue as a triphasic continuum of neurons, glia and the extracellular space. A thermodynamically consistent incorporation of the major biophysical effects, including ionic electrodiffusion and osmotic water flow, allows for the computation of important physiological variables including the extracellular voltage (DC) shift...
October 2016: Bulletin of Mathematical Biology
https://www.readbyqxmd.com/read/27683450/incidence-hemodynamic-and-electrical-characteristics-of-spreading-depolarization-in-a-swine-model-are-affected-by-local-but-not-by-intravenous-application-of-magnesium
#14
Edgar Santos, Fiorella León, Humberto Silos, Renan Sanchez-Porras, C William Shuttleworth, Andreas Unterberg, Oliver W Sakowitz
The aim was to characterize the effects of magnesium sulfate, using i.v. bolus and local administration, using intrinsic signal imaging, and on electrocorticographic activity during the induction and propagation of spreading depolarizations in the gyrencephalic porcine brain. Local application of magnesium sulfate led to a complete inhibition of spreading depolarizations. One hour after washing out the topical magnesium sulfate, re-incidence of the spreading depolarizations was observed in 50% of the hemispheres...
December 2016: Journal of Cerebral Blood Flow and Metabolism
https://www.readbyqxmd.com/read/27677673/large-field-of-view-movement-compensated-intrinsic-optical-signal-imaging-for-the-characterization-of-the-haemodynamic-response-to-spreading-depolarizations-in-large-gyrencephalic-brains
#15
Michael Johannes Schöll, Edgar Santos, Renan Sanchez-Porras, Modar Kentar, Markus Gramer, Humberto Silos, Zelong Zheng, Yuan Gang, Anthony John Strong, Rudolf Graf, Andreas Unterberg, Oliver W Sakowitz, Hartmut Dickhaus
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...
September 27, 2016: Journal of Cerebral Blood Flow and Metabolism
https://www.readbyqxmd.com/read/27614225/traumatic-brain-injury-induced-autoregulatory-dysfunction-and-spreading-depression-related-neurovascular-uncoupling-pathomechanisms-perspectives-and-therapeutic-implications
#16
REVIEW
Peter Toth, Nikolett Szarka, Eszter Farkas, Erzsebet Ezer, Endre Czeiter, Krisztina Amrein, Zoltan Ungvari, Jed A Hartings, Andras Buki, Akos Koller
Traumatic brain injury (TBI) is a major health problem worldwide. In addition to its high mortality (35-40%), survivors are left with cognitive, behavioral, and communicative disabilities. While little can be done to reverse initial primary brain damage caused by trauma, the secondary injury of cerebral tissue due to cerebromicrovascular alterations and dysregulation of cerebral blood flow (CBF) is potentially preventable. This review focuses on functional, cellular, and molecular changes of autoregulatory function of CBF (with special focus on cerebrovascular myogenic response) that occur in cerebral circulation after TBI and explores the links between autoregulatory dysfunction, impaired myogenic response, microvascular impairment, and the development of secondary brain damage...
November 1, 2016: American Journal of Physiology. Heart and Circulatory Physiology
https://www.readbyqxmd.com/read/27581720/regional-temperature-and-quantitative-cerebral-blood-flow-responses-to-cortical-spreading-depolarization-in-the-rat
#17
Chunyan Li, Raj K Narayan, Ping Wang, Jed A Hartings
Regional temperature and quantitative regional cerebral blood flow responses to cortical spreading depolarization in the rat were continuously monitored in the same tissue using a microfabricated thermal diffusion sensor that recalibrates and measures in 5-s cycles. The regional cerebral blood flow response had four phases, including early hyperemia (peak: 226% of baseline; duration: 113.1 ± 14.4 s) and late oligemia (minimum: 57%, duration: 28.4 ± 3.7 min). Temperature rose with the start of the regional cerebral blood flow response to a peak increase of 0...
August 31, 2016: Journal of Cerebral Blood Flow and Metabolism
https://www.readbyqxmd.com/read/27562866/heterogeneous-incidence-and-propagation-of-spreading-depolarizations
#18
Dan Kaufmann, Jeremy J Theriot, Jekaterina Zyuzin, C Austin Service, Joshua C Chang, Y Tanye Tang, Vladimir B Bogdanov, Sylvie Multon, Jean Schoenen, Y Sungtaek Ju, K C Brennan
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...
August 25, 2016: Journal of Cerebral Blood Flow and Metabolism
https://www.readbyqxmd.com/read/27545439/a-rock-salt-type-li-based-oxide-li3ni2ruo6-exhibiting-a-chaotic-ferrimagnetism-with-cluster-spin-glass-dynamics-and-thermally-frozen-charge-carriers
#19
Sanjay Kumar Upadhyay, Kartik K Iyer, S Rayaprol, P L Paulose, E V Sampathkumaran
The area of research to discover new Li containing materials and to understand their physical properties has been of constant interest due to applications potential for rechargeable batteries. Here, we present the results of magnetic investigations on a Li compound, Li3Ni2RuO6, which was believed to be a ferrimagnet below 80 K. While our neutron diffraction (ND) and isothermal magnetization (M) data support ferrimagnetism, more detailed magnetic studies establish that this ferrimagnetic phase exhibits some features similar to spin-glasses...
2016: Scientific Reports
https://www.readbyqxmd.com/read/27544469/pediatric-sudden-unexpected-death-in-epilepsy-what-have-we-learned-from-animal-and-human-studies-and-can-we-prevent-it
#20
REVIEW
Rebecca L Holt, Eric Arehart, Arsen Hunanyan, Nina A Fainberg, Mohamad A Mikati
Several factors, such as epilepsy syndrome, poor compliance, and increased seizure frequency increase the risks of sudden unexpected death in epilepsy (SUDEP). Animal models have revealed that the mechanisms of SUDEP involve initially a primary event, often a seizure of sufficient type and severity, that occurs in a brain, which is vulnerable to SUDEP due to either genetic or antecedent factors. This primary event initiates a cascade of secondary events starting, as some models indicate, with cortical spreading depolarization that propagates to the brainstem where it results in autonomic dysfunction...
May 2016: Seminars in Pediatric Neurology
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