keyword
MENU ▼
Read by QxMD icon Read
search

Potassium current voltage clamp

keyword
https://www.readbyqxmd.com/read/29311162/differential-expression-and-remodeling-of-transient-outward-potassium-currents-in-human-left-ventricles
#1
Eric K Johnson, Steven J Springer, Wei Wang, Edward J Dranoff, Yan Zhang, Evelyn M Kanter, Kathryn A Yamada, Jeanne M Nerbonne
BACKGROUND: Myocardial, transient, outward currents, Ito, have been shown to play pivotal roles in action potential (AP) repolarization and remodeling in animal models. The properties and contribution of Ito to left ventricular (LV) repolarization in the human heart, however, are poorly defined. METHODS AND RESULTS: Whole-cell, voltage-clamp recordings, acquired at physiological (35°C to 37°C) temperatures, from myocytes isolated from the LV of nonfailing human hearts identified 2 distinct transient currents, Ito,fast (Ito,f) and Ito,slow (Ito,s), with significantly (P<0...
January 2018: Circulation. Arrhythmia and Electrophysiology
https://www.readbyqxmd.com/read/29305938/ca2-dependent-potassium-channels-and-cannabinoid-signaling-in-the-endothelium-of-apolipoprotein-e-knockout-mice-before-plaque-formation
#2
Alexander I Bondarenko, Olga Panasiuk, Iryna Okhai, Fabrizio Montecucco, Karim J Brandt, François Mach
Endothelial Ca2+-dependent K+ channels (KCa) regulate endothelial function. We also know that stimulation of type 2 cannabinoid (CB2) receptors ameliorates atherosclerosis. However, whether atherosclerosis is accompanied by altered endothelial KCa- and CB2 receptor-dependent signaling is unknown. By utilizing an in situ patch-clamp approach, we directly evaluated the KCa channel function and the CB2 receptor-dependent electrical responses in the endothelium of aortic strips from young ApoE-/- and C57Bl/6 mice...
January 3, 2018: Journal of Molecular and Cellular Cardiology
https://www.readbyqxmd.com/read/29302214/antidepressant-drug-paroxetine-blocks-the-open-pore-of-kv3-1-potassium-channel
#3
Hyang Mi Lee, Ok Hee Chai, Sang June Hahn, Bok Hee Choi
In patients with epilepsy, depression is a common comorbidity but difficult to be treated because many antidepressants cause pro-convulsive effects. Thus, it is important to identify the risk of seizures associated with antidepressants. To determine whether paroxetine, a very potent selective serotonin reuptake inhibitor (SSRI), interacts with ion channels that modulate neuronal excitability, we examined the effects of paroxetine on Kv3.1 potassium channels, which contribute to highfrequency firing of interneurons, using the whole-cell patch-clamp technique...
January 2018: Korean Journal of Physiology & Pharmacology
https://www.readbyqxmd.com/read/29236481/exploring-the-nanotoxicology-of-mos2-a-study-on-the-interaction-of-mos2-nanoflake-and-k-channels
#4
Zonglin Gu, Leigh D Plant, Xuanyu Meng, Jose Manuel Perez-Aguilar, Zegao Wang, Mingdong Dong, Diomedes E Logothetis, Ruhong Zhou
Molybdenum disulfide (MoS2) nanomaterial has recently found various applications in the biomedical field mainly due to its outstanding physicochemical properties. However, little is known about its interactions with biological systems at the atomic level, which intimately relates to the biocompatibility of the material. To provide insights into the effects of MoS2 in biological entities, we investigated the interactions of MoS2 with proteins from a functionally important membrane family, the ubiquitous potassium (K+) channels...
December 13, 2017: ACS Nano
https://www.readbyqxmd.com/read/29214635/kv4-2-channel-activity-controls-intrinsic-firing-dynamics-of-arcuate-kisspeptin-neurons
#5
Philipe R F Mendonça, Victoria Kyle, Shel-Hwa Yeo, William H Colledge, Hugh P C Robinson
Kisspeptin neurons in the hypothalamus are critically involved in reproductive function, via their effect on GnRH neuron activity and consequent gonadotropin release. Kisspeptin neurons show an intrinsic irregularity of firing, but the mechanism of this remains unclear. To address this, we carried out targeted whole-cell patch-clamp recordings of kisspeptin neurons in the arcuate nucleus (Kiss1Arc ), in brain slices isolated from adult male Kiss-Cre:tdTomato mice. Cells fired irregularly in response to constant current stimuli, with a wide range of spike time variability, and prominent subthreshold voltage fluctuations...
December 6, 2017: Journal of Physiology
https://www.readbyqxmd.com/read/29177805/inhibitory-effects-of-honokiol-on-the-voltage-gated-potassium-channels-in-freshly-isolated-mouse-dorsal-root-ganglion-neurons
#6
Anqi Sheng, Yan Zhang, Guang Li, Guangqin Zhang
Voltage-gated potassium (KV) currents, subdivided into rapidly inactivating A-type currents (I A) and slowly inactivating delayed rectifier currents (I K), play a fundamental role in modulating pain by controlling neuronal excitability. The effects of Honokiol (Hon), a natural biphenolic compound derived from Magnolia officinalis, on KV currents were investigated in freshly isolated mouse dorsal root ganglion neurons using the whole-cell patch clamp technique. Results showed that Hon inhibited I A and I K in concentration-dependent manner...
November 24, 2017: Neurochemical Research
https://www.readbyqxmd.com/read/29168928/regulation-of-kv1-4-potassium-channels-by-pkc-and-ampk-kinases
#7
Martin Nybo Andersen, Lasse Skibsbye, Arnela Saljic, Martin Zahle Larsen, Hanne Borger Rasmussen, Thomas Jespersen
Over the last years extensive kinase-mediated regulation of a number of voltage-gated potassium (Kv) channels important in cardiac electrophysiology has been reported. This includes regulation of Kv1.5, Kv7.1 and Kv11.1 cell surface expression, where the kinase-mediated regulation appears to center around the ubiquitin ligase Nedd4-2. In the present study we examined whether Kv1.4, constituting the cardiac Ito,s current, is subject to similar regulation. In the epithelial Madin-Darby Canine Kidney (MDCK) cell line, which constitutes a highly reproducible model system for addressing membrane targeting, we find, by confocal microscopy, that Kv1...
November 23, 2017: Channels
https://www.readbyqxmd.com/read/29156097/4-aminopyridine-a-pan-kv-channel-inhibitor-that-enhances-kv7-4-currents-and-inhibits-noradrenaline-mediated-contraction-of-rat-mesenteric-small-arteries
#8
Makhala M Khammy, Sukhan Kim, Bo H Bentzen, Soojung Lee, Inyeoung Choi, Christian Aalkjaer, Thomas A Jepps
BACKGROUND AND PURPOSE: Kv7.4 and Kv7.5 channels are regulators of vascular tone. 4-aminopyridine (4-AP) is considered a broad inhibitor of voltage-gated potassium (KV ) channels, with little inhibitory effect on Kv7 family members at millimolar concentrations. However, the effect of 4-AP on Kv7 channels has not been systematically studied. The aim of this study was to investigate the pharmacological activity of 4-AP on Kv7.4 and Kv7.5 channels and characterise the effect of 4-AP on rat resistance arteries...
November 20, 2017: British Journal of Pharmacology
https://www.readbyqxmd.com/read/29133173/effects-of-norquetiapine-the-active-metabolite-of-quetiapine-on-cloned-herg-potassium-channels
#9
Hong Joon Lee, Jin-Sung Choi, Bok Hee Choi, Sang June Hahn
Quetiapine is an atypical antipsychotic drug that is widely used for the treatment of schizophrenia. It is mainly metabolized by a cytochrome P450 system in the liver. Norquetiapine is a major active metabolite in humans with a pharmacological profile that differs distinctly from that of quetiapine. We used the whole-cell patch-clamp technique to investigate the effects of norquetiapine on hERG channels that are stably expressed in HEK cells. Quetiapine and norquetiapine inhibited the hERG tail currents at -50mV in a concentration-dependent manner with IC50 values of 8...
November 11, 2017: Neuroscience Letters
https://www.readbyqxmd.com/read/29128793/phytochemicals-genistein-and-capsaicin-modulate-kv2-1-channel-gating
#10
Iván A Aréchiga-Figueroa, Rita Morán-Zendejas, Mayra Delgado-Ramírez, Aldo A Rodríguez-Menchaca
BACKGROUND: Phytochemicals are a large group of plant-derived compounds that have a broad range of pharmacological effects. Some of these effects are derived from their action on transport proteins, including ion channels. The present study investigates the effects of the phytochemicals genistein and capsaicin on voltage-gated potassium Kv2.1 channels. METHODS: The whole-cell patch clamp technique was used to explore the regulation of Kv2.1 channels expressed in HEK293 cells by genistein and capsaicin...
June 3, 2017: Pharmacological Reports: PR
https://www.readbyqxmd.com/read/29117522/the-fast-component-of-herg-gating-charge-an-interaction-between-d411-in-the-s1-and-s4-residues
#11
Ying Dou, Logan C Macdonald, Yue Wu, David Fedida
Kv11.1 (hERG) is a voltage-gated potassium channel that shows very slow ionic current activation kinetics, and an unusual underlying biphasic gating charge movement with fast and slow components that differ greatly in time course. The structural basis and role of the fast component of gating charge (Qfast) is unclear, and its relationship to the slow activation of hERG channels is not understood. In this study we have used the cut-open oocyte voltage-clamp technique to investigate the relationship of fast gating charge movement-to-residue interactions between D411 at the bottom of the S1, and lower S4 domain charged and uncharged residues...
November 7, 2017: Biophysical Journal
https://www.readbyqxmd.com/read/29097440/desensitization-and-tolerance-of-mu-opioid-receptors-on-pontine-kolliker-fuse-neurons
#12
Erica S Levitt, John T Williams
Acute desensitization of mu opioid receptors is thought to be an initial step in the development of tolerance to opioids. Given the resistance of the respiratory system to develop tolerance, desensitization of neurons in the Kölliker-Fuse (KF), a key area in the respiratory circuit, was examined. The activation of G protein-coupled inwardly rectifying potassium (GIRK) current was measured using whole-cell voltage-clamp recordings from KF and locus coeruleus (LC) neurons contained in acute rat brain slices...
November 2, 2017: Molecular Pharmacology
https://www.readbyqxmd.com/read/29081746/the-natural-flavone-acacetin-blocks-small-conductance-ca-2-activated-k-channels-stably-expressed-in-hek-293-cells
#13
Kui-Hao Chen, Hui Liu, Hai-Ying Sun, Man-Wen Jin, Guo-Sheng Xiao, Yan Wang, Gui-Rong Li
The natural flavone acacetin inhibits several voltage-gated potassium currents in atrial myocytes, and has anti-atrial fibrillation (AF) effect in experimental AF models. The present study investigates whether acacetin inhibits the Ca(2+)-activated potassium (KCa) currents, including small conductance (SKCa1, SKCa2, and SKCa3), intermediate conductance (IKCa), and large-conductance (BKCa) channels stably expressed in HEK 293 cells. The effects of acacetin on these KCa channels were determined with a whole-cell patch voltage-clamp technique...
2017: Frontiers in Pharmacology
https://www.readbyqxmd.com/read/29078287/pip2-mediates-functional-coupling-and-pharmacology-of-neuronal-kcnq-channels
#14
Robin Y Kim, Stephan A Pless, Harley T Kurata
Retigabine (RTG) is a first-in-class antiepileptic drug that suppresses neuronal excitability through the activation of voltage-gated KCNQ2-5 potassium channels. Retigabine binds to the pore-forming domain, causing a hyperpolarizing shift in the voltage dependence of channel activation. To elucidate how the retigabine binding site is coupled to changes in voltage sensing, we used voltage-clamp fluorometry to track conformational changes of the KCNQ3 voltage-sensing domains (VSDs) in response to voltage, retigabine, and PIP2...
November 7, 2017: Proceedings of the National Academy of Sciences of the United States of America
https://www.readbyqxmd.com/read/29072259/barbaloin-inhibits-ventricular-arrhythmias-in-rabbits-by-modulating-voltage-gated-ion-channels
#15
Zhen-Zhen Cao, You-Jia Tian, Jie Hao, Pei-Hua Zhang, Zhi-Pei Liu, Wan-Zhen Jiang, Meng-Liu Zeng, Pei-Pei Zhang, Ji-Hua Ma
Barbaloin (10-β-D-glucopyranosyl-1,8-dihydroxy-3-(hydroxymethyl)-9(10H)-anthracenone) is extracted from the aloe plant and has been reported to have anti-inflammatory, antitumor, antibacterial, and other biological activities. Here, we investigated the effects of barbaloin on cardiac electrophysiology, which has not been reported thus far. Cardiac action potentials (APs) and ionic currents were recorded in isolated rabbit ventricular myocytes using whole-cell patch-clamp technique. Additionally, the antiarrhythmic effect of barbaloin was examined in Langendorff-perfused rabbit hearts...
October 26, 2017: Acta Pharmacologica Sinica
https://www.readbyqxmd.com/read/29055091/functional-interaction-of-junctophilin-2-with-small-conductance-ca-2-activated-potassium-channel-subtype-2-sk2-in-mouse-cardiac-myocytes
#16
Hong K Fan, Tian X Luo, Wei D Zhao, Yong H Mu, Yang Yang, Wen J Guo, Hui Y Tu, Qian Zhang
AIM: Junctophilins (JPs), a protein family of the junctional membrane complex, maintain the close conjunction between cell surface and intracellular membranes in striate muscle cells mediating the cross talk between extracellular Ca(2+) entry and intracellular Ca(2+) release. The small conductance Ca(2+) -activated K(+) channels are activated by the intracellular calcium and play an essential role in the cardiac action potential profile. Molecular mechanisms of regulation of the SK channels are still uncertain...
October 21, 2017: Acta Physiologica
https://www.readbyqxmd.com/read/29046423/the-intrinsic-physiology-of-inhibitory-neurons-changes-over-auditory-development
#17
Briana J Carroll, Richard Bertram, Richard L Hyson
During auditory development, changes in membrane properties promote the ability of excitatory neurons in the brainstem to code aspects of sound, including the level and timing of a stimulus. Some of these changes coincide with hearing onset, suggesting that sound-driven neural activity produces developmental plasticity of ion channel expression. While it is known that the coding properties of excitatory neurons are modulated by inhibition in the mature system, it is unknown whether there are also developmental changes in the membrane properties of brainstem inhibitory neurons...
October 18, 2017: Journal of Neurophysiology
https://www.readbyqxmd.com/read/28987626/no-involvement-in-the-inhibition-of-ghrelin-on-voltage-dependent-potassium-currents-in-rat-hippocampal-cells
#18
Yong Lu, Shaokang Dang, Xu Wang, Junli Zhang, Lin Zhang, Qian Su, Huiping Zhang, Tianwei Lin, Xiaoxiao Zhang, Yurong Zhang, Hongli Sun, Zhongliang Zhu, Hui Li
Ghrelin is a peptide hormone that plays an important role in promoting appetite, regulating distribution and rate of use of energy, cognition, and mood disorders, but the relevant neural mechanisms of these function are still not clear. In this study, we examined the effect of ghrelin on voltage-dependent potassium (K(+)) currents in hippocampal cells of 1-3 days SD rats by whole-cell patch-clamp technique, and discussed whether NO was involved in this process. The results showed that ghrelin significantly inhibited the voltage-dependent K(+) currents in hippocampal cells, and the inhibitory effect was more significant when L-arginine was co-administered...
October 4, 2017: Brain Research
https://www.readbyqxmd.com/read/28982705/sk-channels-regulate-resting-properties-and-signaling-reliability-of-a-developing-fast-spiking-neuron
#19
Yihui Zhang, Hai Huang
Reliable and precise signal transmission is essential in circuits of the auditory brainstem to encode timing with submillisecond accuracy. Globular bushy cells reliably and faithfully transfer spike signals to the principal neurons of the medial nucleus of the trapezoid body (MNTB) through the giant glutamatergic synapse, the calyx of Held. Thus, the MNTB works as a relay nucleus that preserves the temporal pattern of firing at high frequency. Using whole-cell patch-clamp recordings, we observed a K(+) conductance mediated by small-conductance calcium-activated potassium (SK) channels in the MNTB neurons from rats of either sex...
November 1, 2017: Journal of Neuroscience: the Official Journal of the Society for Neuroscience
https://www.readbyqxmd.com/read/28964116/revealing-kinetics-and-state-dependent-binding-properties-of-ikur-targeting-drugs-that-maximize-atrial-fibrillation-selectivity
#20
Nicholas Ellinwood, Dobromir Dobrev, Stefano Morotti, Eleonora Grandi
The KV1.5 potassium channel, which underlies the ultra-rapid delayed-rectifier current (IKur) and is predominantly expressed in atria vs. ventricles, has emerged as a promising target to treat atrial fibrillation (AF). However, while numerous KV1.5-selective compounds have been screened, characterized, and tested in various animal models of AF, evidence of antiarrhythmic efficacy in humans is still lacking. Moreover, current guidelines for pre-clinical assessment of candidate drugs heavily rely on steady-state concentration-response curves or IC50 values, which can overlook adverse cardiotoxic effects...
September 2017: Chaos
keyword
keyword
16180
1
2
Fetch more papers »
Fetching more papers... Fetching...
Read by QxMD. Sign in or create an account to discover new knowledge that matter to you.
Remove bar
Read by QxMD icon Read
×

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"