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voltage gated potassium channel

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https://www.readbyqxmd.com/read/28443815/molecular-mechanism-of-voltage-dependent-potentiation-of-kcnh-potassium-channels
#1
William N Zagotta, Gucan Dai
EAG-like (ELK) voltage-gated potassium channels are abundantly expressed in the brain. These channels exhibit a behavior called voltage-dependent potentiation (VDP), which appears to be a specialization to dampen the hyperexitability of neurons. VDP manifests as a potentiation of current amplitude, hyperpolarizing shift in voltage sensitivity, and slowing of deactivation in response to a depolarizing prepulse. Here we show that VDP of D. rerio ELK channels involves the structural interaction between the intracellular N-terminal eag domain and C-terminal CNBHD...
April 26, 2017: ELife
https://www.readbyqxmd.com/read/28432047/delayed-lgi1-seropositivity-in-voltage-gated-potassium-channel-vgkc-complex-antibody-limbic-encephalitis
#2
Michael Sweeney, Jonathan Galli, Scott McNally, Anne Tebo, Thomas Haven, Perla Thulin, Stacey L Clardy
We utilise a clinical case to highlight why exclusion of voltage-gated potassium channel (VGKC)-complex autoantibody testing in serological evaluation of patients may delay or miss the diagnosis. A 68-year-old man presented with increasing involuntary movements consistent with faciobrachial dystonic seizures (FBDS). Initial evaluation demonstrated VGKC antibody seropositivity with leucine-rich glioma-inactivated 1 (LGI1) and contactin-associated protein-like 2 (CASPR2) seronegativity. Aggressive immunotherapy with methylprednisolone and plasmapheresis was started early in the course of his presentation...
April 20, 2017: BMJ Case Reports
https://www.readbyqxmd.com/read/28430359/sulfur-containing-gaseous-signal-molecules-ion-channels-and-cardiovascular-diseases
#3
REVIEW
Wen Yu, Hongfang Jin, Chaoshu Tang, Junbao Du, Zhiren Zhang
Sulfur-containing gaseous signal molecules including hydrogen sulfide (H2 S) and sulfur dioxide (SO2 ) were previously recognized as toxic gases. However, extensive studies have revealed that they can be generated in the cardiovascular system via a sulfur-containing amino acid metabolic pathway, playing an important part in cardiovascular physiology and pathophysiology. Ion channels are pore-forming membrane proteins present in the membrane of all biological cells; functions include establishing a resting membrane potential and controlling action potentials and other electrical signals by conducting ions across the cell membrane...
April 21, 2017: British Journal of Pharmacology
https://www.readbyqxmd.com/read/28424014/semi-quantitative-analysis-of-cerebral-fdg-pet-reveals-striatal-hypermetabolism-and-normal-cortical-metabolism-in-a-case-of-vgkcc-limbic-encephalitis
#4
Patrick Moloney, Ruth Boylan, Marwa Elamin, Sean O'Riordan, Ronan Killeen, Christopher McGuigan
In the context of delayed autoimmune encephalitis antibody results, functional imaging can support the diagnosis of limbic encephalitis associated with anti-voltage-gated potassium channel complex (VGKCC) antibodies. Here we present a typical case of VGKCC encephalitis in a 69-year-old woman whose symptoms responded to plasmapheresis. A cerebral 18F-fluoro-2-deoxy-d-glucose positron emission tomography (FDG-PET) scan performed prior to commencing treatment revealed striatal hypermetabolism assessed qualitatively and semi-quantitatively, with normal uptake in the cortex and cerebellum when analysed semi-quantitatively...
April 2017: Neuroradiology Journal
https://www.readbyqxmd.com/read/28422818/inhibition-of-metabotropic-glutamate-receptor-subtype-1-alters-the-excitability-of-the-commissural-pyramidal-neuron-in-the-rat-anterior-cingulate-cortex-after-chronic-constriction-injury-to-the-sciatic-nerve
#5
Shi-Hao Gao, Lin-Lin Shen, Hui-Zhong Wen, Yan-Dong Zhao, Huai-Zhen Ruan
BACKGROUND: Inhibition of the metabotropic glutamate receptor subtype 1 in the anterior cingulate cortex has an analgesic effect during sustained nociceptive hypersensitivity. However, the specific changes in different subtypes of anterior cingulate cortex layer 5 pyramidal neurons, as well as the distinct effect of metabotropic glutamate receptor subtype 1 inhibition on different neuronal subtypes, have not been well studied. METHODS: Retrograde labeling combined with immunofluorescence, whole cell clamp recording, and behavioral tests combined with RNA interference were performed in a rat model of chronic constriction injury to the sciatic nerve...
April 19, 2017: Anesthesiology
https://www.readbyqxmd.com/read/28418022/the-value-of-lgi1-caspr2-and-voltage-gated-potassium-channel-antibodies-in-encephalitis
#6
REVIEW
Agnes van Sonderen, Mar Petit-Pedrol, Josep Dalmau, Maarten J Titulaer
The discovery, in 2010, of autoantibodies against the extracellular proteins LGI1 and Caspr2 facilitated a change of view regarding the clinical importance of voltage-gated potassium channel (VGKC) antibodies. Currently, these antibodies are all classified as VGKC-complex antibodies, and are commonly considered to have a similar clinical value. However, studies from the past few years show that the immune responses mediated by these antibodies have differing clinical relevance. Here, we review the clinical importance of these immune responses in three settings: patients with anti-LGI1 antibodies, patients with anti-Caspr2 antibodies, and patients with antibodies against the VGKC complex that lack LGI1 and Caspr2 specificity...
April 18, 2017: Nature Reviews. Neurology
https://www.readbyqxmd.com/read/28411148/behavioural-characterization-of-ankyring-deficient-mice-a-model-for-ank3-related-disorders
#7
I M van der Werf, D Van Dam, S Missault, B Yalcin, P P De Deyn, G Vandeweyer, R F Kooy
ANK3 encodes AnkyrinG (AnkG), a member of the Ankyrin family that is expressed in several different isoforms in many tissues. A unique serine-rich domain and tail domain in the two largest isoforms of AnkG (270 and 480kDa), restrict AnkG to the axon initial segment and nodes of Ranvier of myelinated neurons. At these sites, AnkG is a master regulator, coordinating the strict clustering of components necessary for proper action potential initiation and propagation along the axon. These components include voltage-gated sodium channels, potassium channels and members of the L1 cell adhesion molecule family...
April 11, 2017: Behavioural Brain Research
https://www.readbyqxmd.com/read/28408328/trpa1-expression-levels-and-excitability-brake-by-kv-channels-influence-cold-sensitivity-of-trpa1-expressing-neurons
#8
Tosifa Memon, Kevin Chase, Lee S Leavitt, Baldomero M Olivera, Russell W Teichert
The molecular sensor of innocuous (painless) cold sensation is well-established to be transient receptor potential cation channel, subfamily M, member 8 (TRPM8). However, the role of transient receptor potential cation channel, subfamily A, member 1 (TRPA1) in noxious (painful) cold sensation has been controversial. We find that TRPA1 channels contribute to the noxious cold sensitivity of mouse somatosensory neurons, independent of TRPM8 channels, and that TRPA1-expressing neurons are largely non-overlapping with TRPM8-expressing neurons in mouse dorsal-root ganglia (DRG)...
April 10, 2017: Neuroscience
https://www.readbyqxmd.com/read/28405806/rearrangement-of-potassium-ions-and-kv1-1-kv1-2-potassium-channels-in-regenerating-axons-following-end-to-end-neurorrhaphy-ionic-images-from-tof-sims
#9
Chiung-Hui Liu, Hung-Ming Chang, Tsung-Huan Wu, Li-You Chen, Yin-Shuo Yang, To-Jung Tseng, Wen-Chieh Liao
The voltage-gated potassium channels Kv1.1 and Kv1.2 that cluster at juxtaparanodal (JXP) regions are essential in the regulation of nerve excitability and play a critical role in axonal conduction. When demyelination occurs, Kv1.1/Kv1.2 activity increases, suppressing the membrane potential nearly to the equilibrium potential of K(+), which results in an axonal conduction blockade. The recovery of K(+)-dependent communication signals and proper clustering of Kv1.1/Kv1.2 channels at JXP regions may directly reflect nerve regeneration following peripheral nerve injury...
April 12, 2017: Histochemistry and Cell Biology
https://www.readbyqxmd.com/read/28390823/the-expression-and-activity-of-kv3-4-channel-subunits-are-precociously-upregulated-in-astrocytes-exposed-to-a%C3%AE-oligomers-and-in-astrocytes-of-alzheimer-s-disease-tg2576-mice
#10
Francesca Boscia, Anna Pannaccione, Roselia Ciccone, Antonella Casamassa, Cristina Franco, Ilaria Piccialli, Valeria de Rosa, Antonio Vinciguerra, Gianfranco Di Renzo, Lucio Annunziato
Astrocyte dysfunction emerges early in Alzheimer's disease (AD) and may contribute to its pathology and progression. Recently, the voltage gated potassium channel KV3.4 subunit, which underlies the fast-inactivating K(+) currents, has been recognized to be relevant for AD pathogenesis and is emerging as a new target candidate for AD. In the present study, we investigated both in in vitro and in vivo models of AD the expression and functional activity of KV3.4 potassium channel subunits in astrocytes. In primary astrocytes our biochemical, immunohistochemical, and electrophysiological studies demonstrated a time-dependent upregulation of KV3...
June 2017: Neurobiology of Aging
https://www.readbyqxmd.com/read/28387543/effect-of-4-aminopyridine-on-genioglossus-muscle-activity-during-sleep-in-healthy-adults
#11
Luigi Taranto-Montemurro, Scott A Sands, Ali Azarbarzin, Melania Marques, Camila M de Melo, Bradley A Edwards, Danny J Eckert, Ludovico Messineo, David P White, Andrew Wellman
RATIONALE: The reduction in upper airway muscle activity from wakefulness to sleep plays a key role in the development of obstructive sleep apnea. Potassium (K+) channels have been recently identified as the downstream mechanisms through which hypoglossal motoneuron membrane excitability is reduced both in non-REM (NREM) and REM sleep. In animal models, the administration of 4-aminopyridine (4-AP), a voltage-gated K+ channel blocker, increased genioglossus activity during wakefulness and across all sleep stages...
April 7, 2017: Annals of the American Thoracic Society
https://www.readbyqxmd.com/read/28383569/gating-mechanisms-underlying-deactivation-slowing-by-two-kcnq1-atrial-fibrillation-mutations
#12
Gary Peng, Rene Barro-Soria, Kevin J Sampson, H Peter Larsson, Robert S Kass
KCNQ1 is a voltage-gated potassium channel that is modulated by the beta-subunit KCNE1 to generate IKs, the slow delayed rectifier current, which plays a critical role in repolarizing the cardiac action potential. Two KCNQ1 gain-of-function mutations that cause a genetic form of atrial fibrillation, S140G and V141M, drastically slow IKs deactivation. However, the underlying gating alterations remain unknown. Voltage clamp fluorometry (VCF) allows simultaneous measurement of voltage sensor movement and current through the channel pore...
April 6, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28383553/oxidation-of-kcnb1-potassium-channels-triggers-apoptotic-integrin-signaling-in-the-brain
#13
Wei Yu, Manasa Gowda, Yashsavi Sharad, Surindo A Singh, Federico Sesti
Oxidative modification of the voltage-gated potassium (K(+)) channel KCNB1 promotes apoptosis in the neurons of cortex and hippocampus through a signaling pathway mediated by Src tyrosine kinases. How oxidation of the channel is transduced into Src recruitment and activation, however, was not known. Here we show that the apoptotic signal originates from integrins, which form macromolecular complexes with KCNB1 channels. The initial stimulus is transduced to Fyn and possibly other Src family members by focal adhesion kinase (FAK)...
April 6, 2017: Cell Death & Disease
https://www.readbyqxmd.com/read/28377405/the-conformational-state-of-herg1-channels-determines-integrin-association-downstream-signaling-and-cancer-progression
#14
Andrea Becchetti, Silvia Crescioli, Francesca Zanieri, Giulia Petroni, Raffaella Mercatelli, Stefano Coppola, Luca Gasparoli, Massimo D'Amico, Serena Pillozzi, Olivia Crociani, Matteo Stefanini, Antonella Fiore, Laura Carraresi, Virginia Morello, Sagar Manoli, Maria Felice Brizzi, Davide Ricci, Mauro Rinaldi, Alessio Masi, Thomas Schmidt, Franco Quercioli, Paola Defilippi, Annarosa Arcangeli
Ion channels regulate cell proliferation, differentiation, and migration in normal and neoplastic cells through cell-cell and cell-extracellular matrix (ECM) transmembrane receptors called integrins. K(+) flux through the human ether-à-go-go-related gene 1 (hERG1) channel shapes action potential firing in excitable cells such as cardiomyocytes. Its abundance is often aberrantly high in tumors, where it modulates integrin-mediated signaling. We found that hERG1 interacted with the β1 integrin subunit at the plasma membrane of human cancer cells...
April 4, 2017: Science Signaling
https://www.readbyqxmd.com/read/28374528/calcium-activated-bkca-channels-govern-dynamic-membrane-depolarizations-of-horizontal-cells-in-rodent-retina
#15
Xiaoping Sun, Arlene A Hirano, Nicholas C Brecha, Steven Barnes
Large conductance, calcium-activated potassium (BKCa ) channels have numerous roles in neurons including the regulation of membrane excitability, intracellular [Ca(2+) ] regulation, and neurotransmitter release. In the retina, they have been identified in photoreceptors, bipolar cells, amacrine cells, and ganglion cells, but have not been conclusively identified in mammalian horizontal cells. We found that outward current recorded between -30 mV and +60 mV is carried primarily in BKCa channels in isolated horizontal cells of rats and mice...
April 4, 2017: Journal of Physiology
https://www.readbyqxmd.com/read/28370099/the-electric-fence-to-cell-cycle-progression-do-local-changes-in-membrane-potential-facilitate-disassembly-of-the-primary-cilium-timely-and-localized-expression-of-a-potassium-channel-may-set-the-conditions-that-allow-retraction-of-the-primary-cilium
#16
REVIEW
Diana Urrego, Araceli Sánchez, Adam P Tomczak, Luis A Pardo
Kv10.1 is a voltage-gated potassium channel relevant for tumor biology, but the underlying mechanism is still unclear. We propose that Kv10.1 plays a role coordinating primary cilium disassembly with cell cycle progression through localized changes of membrane potential at the ciliary base. Most non-dividing cells display a primary cilium, an antenna-like structure important for cell physiology. The cilium is disassembled when the cell divides, which requires an increase of Ca(2+) concentration and a redistribution of phospholipids in its basal region, both of which would be facilitated by local hyperpolarization...
March 30, 2017: BioEssays: News and Reviews in Molecular, Cellular and Developmental Biology
https://www.readbyqxmd.com/read/28369215/focal-ca3-hippocampal-subfield-atrophy-following-lgi1-vgkc-complex-antibody-limbic-encephalitis
#17
Thomas D Miller, Trevor T-J Chong, Anne M Aimola Davies, Tammy W C Ng, Michael R Johnson, Sarosh R Irani, Angela Vincent, Masud Husain, Saiju Jacob, Paul Maddison, Christopher Kennard, Penny A Gowland, Clive R Rosenthal
Magnetic resonance imaging has linked chronic voltage-gated potassium channel (VGKC) complex antibody-mediated limbic encephalitis with generalized hippocampal atrophy. However, autoantibodies bind to specific rodent hippocampal subfields. Here, human hippocampal subfield (subiculum, cornu ammonis 1-3, and dentate gyrus) targets of immunomodulation-treated LGI1 VGKC-complex antibody-mediated limbic encephalitis were investigated using in vivo ultra-high resolution (0.39 × 0.39 × 1.0 mm3) 7.0 T magnetic resonance imaging [n = 18 patients, 17 patients (94%) positive for LGI1 antibody and one patient negative for LGI1/CASPR2 but positive for VGKC-complex antibodies, mean age: 64...
March 28, 2017: Brain: a Journal of Neurology
https://www.readbyqxmd.com/read/28361268/resveratrol-attenuates-a%C3%AE-induced-early-hippocampal-neuron-excitability-impairment-via-recovery-of-function-of-potassium-channels
#18
Hongqiang Yin, Hui Wang, Hui Zhang, Na Gao, Tao Zhang, Zhuo Yang
Alzheimer's disease (AD) is an age-related neurodegenerative disease. Amyloid-β (Aβ) is not only the morphological hallmark but also the initiator of the pathology process of AD. As a natural compound found in grapes, resveratrol shows a protective effect on the pathophysiology of AD, but the underlying mechanism is not very clear. This study was to investigate whether resveratrol could attenuate Aβ-induced early impairment in hippocampal neuron excitability and the underlying mechanism. The excitability and voltage-gated potassium currents were examined in rat hippocampal CA1 pyramidal neurons by using whole-cell patch-clamp technique...
March 30, 2017: Neurotoxicity Research
https://www.readbyqxmd.com/read/28360986/confusion-faciobrachial-dystonic-seizures-and-critical-hyponatremia-in-a-patient-with-voltage-gated-potassium-channel-encephalitis
#19
Julian Yaxley
Autoimmune limbic encephalitis is a rare cause of encephalitic disease. It is associated with various target antigens and is difficult to diagnose, and experience with its treatment is limited. This case report describes a 69-year-old man, who presented with life-threatening hyponatremia and confusion, following several months of gradually worsening faciobrachial dystonic seizures. Faciobrachial dystonic seizures are a well-described feature classically observed in voltage-gated potassium channel autoimmune encephalitis...
March 2017: Korean Journal of Family Medicine
https://www.readbyqxmd.com/read/28349975/mechanism-of-functional-interaction-between-potassium-channel-kv1-3-and-sodium-channel-navbeta1-subunit
#20
Tomoya Kubota, Ana M Correa, Francisco Bezanilla
The voltage-gated potassium channel subfamily A member 3 (Kv1.3) dominantly expresses on T cells and neurons. Recently, the interaction between Kv1.3 and NavBeta1 subunits has been explored through ionic current measurements, but the molecular mechanism has not been elucidated yet. We explored the functional interaction between Kv1.3 and NavBeta1 through gating current measurements using the Cut-open Oocyte Voltage Clamp (COVC) technique. We showed that the N-terminal 1-52 sequence of hKv1.3 disrupts the channel expression on the Xenopus oocyte membrane, suggesting a potential role as regulator of hKv1...
March 28, 2017: Scientific Reports
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