Read by QxMD icon Read

Voltage clamp

Ben Warren, Tom Matheson
Insect auditory receivers provide an excellent comparative resource to understand general principles of auditory transduction, but analysis of the electrophysiological properties of the auditory neurons has been hampered by their tiny size and inaccessibility. Here we pioneer patch-clamp recordings from the auditory neurons of Müller-s Organ of the desert locust Schistocerca gregaria to characterise dendritic spikes, axonal spikes and the transduction current. We demonstrate that dendritic spikes, elicited by sound stimuli, trigger axonal spikes, and that both types are sodium- and voltage-dependent and blocked by TTX...
March 14, 2018: Journal of Neuroscience: the Official Journal of the Society for Neuroscience
Wen Dun, Peter Danilo, Peter J Mohler, Penelope A Boyden
Cardiac Na+ channel remodeling provides a critical substrate for generation of reentrant arrhythmias in border zones of the infarcted canine heart. Recent studies show that Nav1.5 cytoskeletal- and endosomal-based membrane trafficking and function are linked to tubulin, microtubular (MT) networks, and Eps15 homology domain containing proteins like EHD4. AIM: Our objective is to understand the relation of tubulin and EHD4 to Nav 1.5 channel protein remodeling observed in border zone cells (IZs) when arrhythmias are known to occur; that is, 3-h, 48-h and 5-day post coronary occlusion...
March 10, 2018: Life Sciences
Hyemi Bae, Jeongyoon Choi, Young-Won Kim, Donghee Lee, Jung-Ha Kim, Jae-Hong Ko, Hyoweon Bang, Taeho Kim, Inja Lim
This study investigated the expression of voltage-gated K⁺ (KV ) channels in human cardiac fibroblasts (HCFs), and the effect of nitric oxide (NO) on the KV currents, and the underlying phosphorylation mechanisms. In reverse transcription polymerase chain reaction, two types of KV channels were detected in HCFs: delayed rectifier K⁺ channel and transient outward K⁺ channel. In whole-cell patch-clamp technique, delayed rectifier K⁺ current (IK ) exhibited fast activation and slow inactivation, while transient outward K⁺ current (Ito ) showed fast activation and inactivation kinetics...
March 12, 2018: International Journal of Molecular Sciences
Peng Yu, Lili Hu, Jinyan Xie, Sisi Chen, Lin Huang, Zixuan Xu, Xiao Liu, Qiongqiong Zhou, Ping Yuan, Xia Yan, Jiejin Jin, Yang Shen, Wengen Zhu, Linghua Fu, Qi Chen, Jianhua Yu, Jianxin Hu, Qing Cao, Rong Wan, Kui Hong
BACKGROUND: Cardiovascular complications are major causes of mortality and morbidity in diabetic patients. The mechanisms underlying the progression of diabetic heart (DH) to ventricular arrhythmias are unclear. O-linked GlcNAcylation (O-GlcNAc) is a reversible post-translational modification for the regulation of diverse cellular processes. The purpose of this study was to assess whether the cardiac voltage-gated sodium channel (Nav1.5) is subjected to O-linked GlcNAcylation (O-GlcNAc), which plays an essential role in DH-induced arrhythmias...
February 27, 2018: International Journal of Cardiology
Martin Loynaz Prieto, Kamyar Firouzi, Butrus T Khuri-Yakub, Merritt Maduke
Ultrasound (US) can modulate the electrical activity of the excitable tissues, but the mechanisms underlying this effect are not understood at the molecular level or in terms of the physical modality through which US exerts its effects. Here, we report an experimental system that allows for stable patch-clamp recording in the presence of US at 43 MHz, a frequency known to stimulate neural activity. We describe the effects of US on two ion channels proposed to be involved in the response of excitable cells to US: the mechanosensitive Piezo1 channel and the voltage-gated sodium channel NaV 1...
March 7, 2018: Ultrasound in Medicine & Biology
Steven T Walston, Robert H Chow, James D Weiland
This in vitro investigation examines the response of retinal bipolar cells to extracellular electrical stimulation. 
 Approach: In vitro investigations characterizing the response of retinal neurons to electrical stimulation have primarily focused on retinal ganglion cells because they are the output neurons of the retina and their superficial position in the retina makes them readily accessible to in vitro recording techniques. Thus, the majority of information regarding the response of inner retinal neurons has been inferred from ganglion cell activity...
March 7, 2018: Journal of Neural Engineering
Marit Poffers, Nathalie Bühne, Christine Herzog, Anja Thorenz, Rongjun Chen, Faikah Güler, Axel Hage, Andreas Leffler, Frank Echtermeyer
BACKGROUND: Voltage-gated sodium channels generate action potentials in excitable cells, but they have also been attributed noncanonical roles in nonexcitable cells. We hypothesize that voltage-gated sodium channels play a functional role during extravasation of neutrophils. METHODS: Expression of voltage-gated sodium channels was analyzed by polymerase chain reaction. Distribution of Nav1.3 was determined by immunofluorescence and flow cytometry in mouse models of ischemic heart and kidney injury...
March 6, 2018: Anesthesiology
Petra Lassuthova, Adriana P Rebelo, Gianina Ravenscroft, Phillipa J Lamont, Mark R Davis, Fiore Manganelli, Shawna M Feely, Chelsea Bacon, Dana Šafka Brožková, Jana Haberlova, Radim Mazanec, Feifei Tao, Cima Saghira, Lisa Abreu, Steve Courel, Eric Powell, Elena Buglo, Dana M Bis, Megan F Baxter, Royston W Ong, Lorna Marns, Yi-Chung Lee, Yunhong Bai, Daniel G Isom, René Barro-Soria, Ki W Chung, Steven S Scherer, H Peter Larsson, Nigel G Laing, Byung-Ok Choi, Pavel Seeman, Michael E Shy, Lucio Santoro, Stephan Zuchner
Although mutations in more than 90 genes are known to cause CMT, the underlying genetic cause of CMT remains unknown in more than 50% of affected individuals. The discovery of additional genes that harbor CMT2-causing mutations increasingly depends on sharing sequence data on a global level. In this way-by combining data from seven countries on four continents-we were able to define mutations in ATP1A1, which encodes the alpha1 subunit of the Na+ ,K+ -ATPase, as a cause of autosomal-dominant CMT2. Seven missense changes were identified that segregated within individual pedigrees: c...
March 1, 2018: American Journal of Human Genetics
Andrew J Shepherd, Aaron D Mickle, Suraj Kadunganattil, Hongzhen Hu, Durga P Mohapatra
Bone metastasis in breast, prostate and lung cancers often leads to chronic pain, which is poorly managed by existing analgesics. The neurobiological mechanisms that underlie chronic pain associated with bone-metastasized cancers are not well understood, but sensitization of peripheral nociceptors by tumor microenvironment factors has been demonstrated to be important. Parathyroid hormone-related peptide (PTHrP) is highly expressed in bone-metastasized breast and prostate cancers, and is critical to growth and proliferation of these tumors in the bone tumor microenvironment...
2018: Frontiers in Cellular Neuroscience
Muriel Amar, Rómulo Aráoz, Bogdan I Iorga, Takeshi Yasumoto, Denis Servent, Jordi Molgó
Prorocentrolides are members of the cyclic imine phycotoxins family. Their chemical structure includes a 26-membered carbo-macrocycle and a 28-membered macrocyclic lactone arranged around a hexahydroisoquinoline that incorporates the characteristic cyclic imine group. Six prorocentrolides are already known. However, their mode of action remains undetermined. The aim of the present work was to explore whether prorocentrolide A acts on nicotinic acetylcholine receptors (nAChRs), using competition-binding assays and electrophysiological techniques...
February 28, 2018: Toxins
Noriyuki Hatano, Susumu Ohya, Yuji Imaizumi, Robert B Clark, Darrell Belke, Wayne R Giles
KEY POINTS: Fibroblasts isolated from adult rat ventricles consistently respond to (5-100 μM) ATP. ATP, ADP, and UTP all elicit similar dose-dependent increases in [Ca2+ ]i . ATP also activates an outwardly rectifying Cl- current; in contrast, ADP and UTP have much smaller electrophysiological effects. This ATP-dependent Cl- current is markedly reduced when: i) [Ca2+ ]i is buffered with BAPTA, or ii) the intrinsic phospholipase C activity in these fibroblasts is inhibited. PCR analysis suggests that the ATP-induced current is generated by the Ca2+ -activated Cl- current transcript TMEM 16F, also denoted ANO6...
March 1, 2018: Experimental Physiology
Eglantina Idrizaj, Rachele Garella, Fabio Francini, Roberta Squecco, Maria Caterina Baccari
AIM: To investigate the signaling pathways involved in the relaxin (RLX) effects on ileal preparations from mice through mechanical and electrophysiological experiments. METHODS: For mechanical experiments, ileal preparations from female mice were mounted in organ baths containing Krebs-Henseleit solution. The mechanical activity was recorded via force-displacement transducers, which were coupled to a polygraph for continuous recording of isometric tension. Electrophysiological measurements were performed in current- and voltage-clamp conditions by a microelectrode inserted in a single smooth muscle cell (SMC) of the ileal longitudinal layer...
February 28, 2018: World Journal of Gastroenterology: WJG
Bailin Liu, Yanping Liu, Ruixiu Shi, Xueqin Feng, Xiang Li, Wenna Zhang, Jue Wu, Na Li, Xiuwen Zhou, Miao Sun, Zhice Xu
BACKGROUND/AIMS: Chronic hypoxia in utero could impair vascular functions in the offspring, underlying mechanisms are unclear. This study investigated functional alteration in large-conductance Ca2+-activated K+ (BK) channels in offspring mesenteric arteries following prenatal hypoxia. METHODS: Pregnant rats were exposed to normoxic control (21% O2, Con) or hypoxic (10.5% O2, Hy) conditions from gestational day 5 to 21, their 7-month-old adult male offspring were tested for blood pressure, vascular BK channel functions and expression using patch clamp and wire myograh technique, western blotting, and qRT-PCR...
February 21, 2018: Cellular Physiology and Biochemistry
Armando Carpaneto, Antonella Gradogna
Plant two-pore channels (TPCs) are non-selective cation channels permeable both to monovalent potassium and divalent calcium. We previously developed a technique that allowed the simultaneous determination of the fluxes of these two ions across the channel by a combined use of patch-clamp and fluorescence. In this paper we studied how potassium and calcium fluxes were influenced by modification of cytosolic concentrations of K+ and Ca2+ . A decrease in cytosolic calcium from 2 to 0.5 mM led to a shift of the activation curve of about +60 mV; although at positive potentials currents were very similar, calcium ion permeation was significantly reduced and the ratio between the total and calcium-mediated current increased about two-fold...
February 24, 2018: Biophysical Chemistry
Nils J G Rorsman, Chau M Ta, Hannah Garnett, Pawel Swietach, Paolo Tammaro
BACKGROUND AND PURPOSE: Optogenetic control of electromechanical coupling in vascular smooth muscle cells (VSMCs) is emerging as a powerful research tool with potential applications in drug discovery and therapeutics. However, the precise ionic mechanisms involved in this control remain unclear. EXPERIMENTAL APPROACH: Cell imaging, patch-clamp electrophysiology, and muscle tension recordings were used to define these mechanisms over a wide range of light stimulations...
February 27, 2018: British Journal of Pharmacology
Mena Abdelsayed, Manpreet Ruprai, Peter C Ruben
E1784K is the most common mixed syndrome SCN5a mutation underpinning both Brugada syndrome type 1 (BrS1) and Long-QT syndrome type 3 (LQT3). The charge reversal mutant enhances the late sodium current (INa ) passed by the cardiac voltage-gated sodium channel (NaV 1.5), delaying cardiac repolarization. Exercise-induced triggers, like elevated temperature and cytosolic calcium, exacerbate E1784K late INa . In this study, we tested the effects of Ranolazine, the late INa blocker, on voltage-dependent and kinetic properties of E1784K at elevated temperature and cytosolic calcium...
February 26, 2018: Scientific Reports
Jacqueline Gayet-Primo, Daniel B Yaeger, Roupen A Khanjian, Teresa Puthussery
Silent voltage-gated potassium channel subunits (KV S) interact selectively with members of the KV 2 channel family to modify their functional properties. The localization and functional roles of these silent subunits remain poorly understood. Mutations in the KV S subunit, KV 8.2 ( KCNV2 ), lead to severe visual impairment in humans, but the basis of these deficits remain unclear. Here, we examined the localization, native interactions and functional properties of KV 8.2-containing channels in mouse, macaque and human photoreceptors of either sex...
February 24, 2018: Journal of Neuroscience: the Official Journal of the Society for Neuroscience
Stefania Piscopo, Euan R Brown
Membrane-nanoparticle interactions are important in determining the effects of manufactured nanomaterials on cell physiology and pathology. Here, silica, titanium, zinc, and magnesium oxide nanoparticles are screened against human hERG (Kv 11.1) voltage-gated potassium channels under a whole-cell voltage clamp. 10 µg mL-1 ZnO uniquely increases the amplitude of the steady-state current, decreases the rate of hERG current inactivation during steady-state depolarization, accelerates channel deactivation during resurgent tail currents, and shows no significant alteration of current activation rate or voltage dependence...
February 26, 2018: Small
Hugo Zeberg, Johanna Nilsson, Peter Århem
Understanding the relationships between the rates and dynamics of current wave forms under voltage clamp conditions is essential for understanding phenomena such as state-dependence and use-dependence, which are fundamental for the action of drugs used as anti-epileptics, anti-arrhythmics, and anesthetics. In the present study, we mathematically analyze models of blocking mechanisms. In previous experimental studies of potassium channels we have shown that the effect of local anesthetics can be explained by binding to channels in the open state...
2018: Frontiers in Cellular Neuroscience
Yanmei Qi, Norbert Mair, Kai K Kummer, Michael G Leitner, María Camprubí-Robles, Michiel Langeslag, Michaela Kress
Sphingosine-1-phosphate (S1P) is a bioactive sphingolipid involved in numerous physiological and pathophysiological processes. We have previously reported a S1P-induced nocifensive response in mice by excitation of sensory neurons via activation of an excitatory chloride current. The underlying molecular mechanism for the S1P-induced chloride conductance remains elusive. In the present study, we identified two CLCN voltage-gated chloride channels, CLCN3 and CLCN5, which mediated a S1P-induced excitatory Cl- current in sensory neurons by combining RNA-seq, adenovirus-based gene silencing and whole-cell electrophysiological voltage-clamp recordings...
2018: Frontiers in Molecular Neuroscience
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"