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Ondrej Balvín, Warren Booth
For over two decades, the bed bug, Cimex lectularius L. (Hemiptera: Cimicidae) has been undergoing a dramatic global resurgence, likely in part to the evolution of mechanisms conferring resistance to insecticides. One such mechanism is knock-down resistance (kdr), resulting from nonsynonymous mutations within the voltage-gated sodium channel (VGSC) gene. To date, three mutations have been identified in C. lectularius, V419L, L925I, and I936F. Using Sanger sequencing, the frequency and distribution of these VGSC mutations across 131 populations collected from the bat-associated and human-associated lineages of C...
March 15, 2018: Journal of Medical Entomology
Qingjuan Hu, Yuping Li, Chao Liu, Li-Ping Huang, Lvming Zeng, Songhua Wang, Hao Song, Hailong Peng, Jianhua Huang, Chong Chen, Li-Hua Yao
Our previous work showed that polysaccharide isolated from Portulaca oleracea L. (POP) has an insulinotropic effect. The voltage-gated Na+ channel (VGSC) in the excitement phase plays an important role. This work aims to study the effect of POP on the voltage-gated Na+ channel current (INa ) and its channel dynamic characteristics in insulin-secreting β-cell line (INS-1) cells of rat. Our results revealed that POP can inhibit the amplitude of INa and improve cell survival in a concentration-dependent manner...
March 4, 2018: Biomedicine & Pharmacotherapy, Biomédecine & Pharmacothérapie
Bashir Adam Ismail, Hmooda Toto Kafy, Jihad Eltaher Sulieman, Krishanthi Subramaniam, Brent Thomas, Abraham Mnzava, Nur Faeza Abu Kassim, Abu Hassan Ahmad, Tessa B Knox, Immo Kleinschmidt, Martin J Donnelly
BACKGROUND: Long-lasting insecticidal nets (LLINs) (with pyrethroids) and indoor residual spraying (IRS) are the cornerstones of the Sudanese malaria control program. Insecticide resistance to the principal insecticides in LLINs and IRS is a major concern. This study was designed to monitor insecticide resistance in Anopheles arabiensis from 140 clusters in four malaria-endemic areas of Sudan from 2011 to 2014. All clusters received LLINs, while half (n = 70), distributed across the four regions, had additional IRS campaigns...
March 2, 2018: Parasites & Vectors
Mónica Rubio Ayala, Tatiana Syrovets, Susanne Hafner, Vitalii Zablotskii, Alexandr Dejneka, Thomas Simmet
Cellular function is modulated by the electric membrane potential controlling intracellular physiology and signal propagation from a motor neuron to a muscle fiber resulting in muscle contraction. Unlike electric fields, magnetic fields are not attenuated by biological materials and penetrate deep into the tissue. We used complex spatiotemporal magnetic fields (17-70 mT) to control intracellular signaling in skeletal muscle cells. By changing different parameters of the alternating magnetic field (amplitude, inversion time, rotation frequency), we induced transient depolarization of cellular membranes leading to i) Na+ influx through voltage-gated sodium channels (VGSC), ii) cytosolic calcium increase, and iii) VGSC- and ryanodine receptor-dependent increase of actin polymerization...
February 16, 2018: Biomaterials
Steven Molinarolo, Daniele Granata, Vincenzo Carnevale, Christopher A Ahern
Voltage-gated sodium channel (VGSC) beta (β) subunits have been called the "overachieving" auxiliary ion channel subunit. Indeed, these subunits regulate the trafficking of the sodium channel complex at the plasma membrane and simultaneously tune the voltage-dependent properties of the pore-forming alpha-subunit. It is now known that VGSC β-subunits are capable of similar modulation of multiple isoforms of related voltage-gated potassium channels, suggesting that their abilities extend into the broader voltage-gated channels...
February 21, 2018: Handbook of Experimental Pharmacology
Ladislav Pazdera, Michael R Sperling, Jay H Harvey, Maria C Sam, Laura A Strom, David Blum, Todd Grinnell, Hailong Cheng
OBJECTIVE: To evaluate the influence of prior use of carbamazepine (CBZ) and other antiepileptic drugs (AEDs) with a putatively similar mechanism of action (inhibition of voltage-gated sodium channels; VGSCs) on seizure outcomes and tolerability when converting to eslicarbazepine acetate (ESL), using data pooled from 2 controlled conversion-to-ESL monotherapy trials (studies: 093-045, 093-046). METHODS: Adults with treatment-resistant focal (partial-onset) seizures were randomized 2:1 to ESL 1600 or 1200 mg once daily...
February 16, 2018: Epilepsia
David Weetman, Craig S Wilding, Daniel E Neafsey, Pie Müller, Eric Ochomo, Alison T Isaacs, Keith Steen, Emily J Rippon, John C Morgan, Henry D Mawejje, Daniel J Rigden, Loyce M Okedi, Martin J Donnelly
Metabolic resistance to pyrethroid insecticides is widespread in Anopheles mosquitoes and is a major threat to malaria control. DNA markers would aid predictive monitoring of resistance, but few mutations have been discovered outside of insecticide-targeted genes. Isofemale family pools from a wild Ugandan Anopheles gambiae population, from an area where operational pyrethroid failure is suspected, were genotyped using a candidate-gene enriched SNP array. Resistance-associated SNPs were detected in three genes from detoxification superfamilies, in addition to the insecticide target site (the Voltage Gated Sodium Channel gene, Vgsc)...
February 13, 2018: Scientific Reports
Carlos Perez, Ghanim Ullah
Beta amyloid (A[Formula: see text] ) associated with Alzheimer's disease (AD) leads to abnormal behavior in inhibitory neurons, resulting in hyperactive neuronal networks, epileptiform behavior, disrupted gamma rhythms, and aberrant synaptic plasticity. Previously, we used a dual modeling-experimental approach to explain several observations, including failure to reliably produce action potentials (APs), smaller AP amplitudes, higher resting membrane potential, and higher membrane depolarization in response to a range of stimuli in hippocampal inhibitory neurons from 12- to 16-month-old female AP Pswe/PSEN1DeltaE9 (APdE9) AD mice as compared to age-matched non-transgenic (NTG) mice...
February 9, 2018: European Biophysics Journal: EBJ
Chong Chen, Songhua Wang, Qingjuan Hu, Lvming Zeng, Hailong Peng, Chao Liu, Li-Ping Huang, Hao Song, Yuping Li, Li-Hua Yao, Wei Meng
BACKGROUND/AIMS: Islet beta cells (β-cells) are unique cells that play a critical role in glucose homeostasis by secreting insulin in response to increased glucose levels. Voltage-gated ion channels in β-cells, such as K+ and Ca2+ channels, contribute to insulin secretion. The response of voltage-gated Na+ channels (VGSCs) in β-cells to the changes in glucose levels remains unknown. This work aims to determine the role of extracellular glucose on the regulation of VGSC. METHODS: The effect of glucose on VGSC currents (INa) was investigated in insulin-secreting β-cell line (INS-1) cells of rats using whole-cell patch clamp techniques, and the effects of glucose on insulin content and cell viability were determined using Enzyme-Linked Immunosorbent Assay (ELISA) and Methylthiazolyldiphenyl-tetrazolium Bromide (MTT) assay methods respectively...
January 24, 2018: Cellular Physiology and Biochemistry
Rene Cervenka, Peter Lukacs, Vaibhavkumar S Gawali, Song Ke, Xaver Koenig, Lena Rubi, Touran Zarrabi, Karlheinz Hilber, Walter Sandtner, Anna Stary-Weinzinger, Hannes Todt
Inactivation of voltage-gated Na+ channels (VGSC) is essential for the regulation of cellular excitability. The molecular rearrangement underlying inactivation is thought to involve the intracellular linker between domains III and IV serving as inactivation lid, the receptor for the lid (domain III S4-S5 linker) and the pore-lining S6 segements. To better understand the role of the domain IV S6 segment in inactivation we performed a cysteine scanning mutagenesis of this region in rNav 1.4 channels and screened the constructs for perturbations in the voltage-dependence of steady state inactivation...
January 12, 2018: Scientific Reports
Zhi-Bin Liu, Chao Liu, Bin Zeng, Li-Ping Huang, Li-Hua Yao
Our previous study revealed that cordycepin features important neuroprotective effects against hypoxic insult by improvement of neuronal electrophysiological function. Modulation on voltage-gated sodium channel (VGSC) in CA1 neurons is the initial event during hypoxia/ischemia. However, no study comprehensively investigated cordycepin on VGSC. Hence, this study investigated modulation effects of cordycepin on VGSC not only in oxygen physiological conditions but also in acute oxygen deprivation injury conditions...
2017: Neural Plasticity
Yonghua Ji
Voltage-gated sodium channels (VGSCs) are critical in generation and conduction of electrical signals in multiple excitable tissues. Natural toxins, produced by animal, plant, and microorganisms, target VGSCs through diverse strategies developed over millions of years of evolutions. Studying of the diverse interaction between VGSC and VGSC-targeting toxins has been contributing to the increasing understanding of molecular structure and function, pharmacology, and drug development potential of VGSCs. This chapter aims to summarize some of the current views on the VGSC-toxin interaction based on the established receptor sites of VGSC for natural toxins...
October 26, 2017: Handbook of Experimental Pharmacology
Zifan Pei, Yanling Pan, Theodore R Cummins
Voltage-gated sodium channels (VGSCs) are critical determinants of excitability. The properties of VGSCs are thought to be tightly controlled. However, VGSCs are also subjected to extensive modifications. Multiple posttranslational modifications that covalently modify VGSCs in neurons and muscle have been identified. These include, but are not limited to, phosphorylation, ubiquitination, palmitoylation, nitrosylation, glycosylation, and SUMOylation. Posttranslational modifications of VGSCs can have profound impact on cellular excitability, contributing to normal and abnormal physiology...
October 26, 2017: Handbook of Experimental Pharmacology
Vaibhavkumar S Gawali, Svilen Simeonov, Martina Drescher, Thomas Knott, Olaf Scheel, John Kudolo, Hanspeter Kählig, Ulla Hochenegg, Alexander Roller, Hannes Todt, Nuno Maulide
The lupin alkaloid sparteine is a well-known chiral diamine with a range of applications in asymmetric synthesis, as well as a blocker of voltage-gated sodium channels (VGSCs). However, there is only scarce information on the VGSC-blocking activity of sparteine derivatives where the structure of the parent alkaloid is retained. Building on the recent renewed availability of sparteine and derivatives we report herein how modification of sparteine at position 2 produces irreversible blockers of VGSCs. These compounds could be clinically envisaged as long-lasting local anesthetics...
November 22, 2017: ChemMedChem
Jassada Saingamsook, Atiporn Saeung, Jintana Yanola, Nongkran Lumjuan, Catherine Walton, Pradya Somboon
BACKGROUND: Mutation of the voltage-gated sodium channel (VGSC) gene, or knockdown resistance (kdr) gene, is an important resistance mechanism of the dengue vector Aedes aegypti mosquitoes against pyrethroids. In many countries in Asia, a valine to glycine substitution (V1016G) and a phenylalanine to cysteine substitution (F1534C) are common in Ae. aegypti populations. The G1016 and C1534 allele frequencies have been increasing in recent years, and hence there is a need to have a simple and inexpensive tool to monitor the alleles in large scale...
October 10, 2017: Parasites & Vectors
Walter Fabricio Silva Martins, Craig Stephen Wilding, Keith Steen, Henry Mawejje, Tiago Rodrigues Antão, Martin James Donnelly
BACKGROUND: Culex quinquefasciatus collected in Uganda, where no vector control interventions directly targeting this species have been conducted, was used as a model to determine if it is possible to detect heterogeneities in selection pressure driven by insecticide application targeting other insect species. METHODOLOGY/PRINCIPAL FINDINGS: Population genetic structure was assessed through microsatellite analysis, and the impact of insecticide pressure by genotyping two target-site mutations, Vgsc-1014F of the voltage-gated sodium channel target of pyrethroid and DDT insecticides, and Ace1-119S of the acetylcholinesterase gene, target of carbamate and organophosphate insecticides...
October 2017: PLoS Neglected Tropical Diseases
A Mercier, P Bois, A Chatelier
Voltage-gated sodium channels (VGSC) are critical determinants of cellular electrical activity through the control of initiation and propagation of action potential. To ensure this role, these proteins are not consistently delivered to the plasma membrane but undergo drastic quality controls throughout various adaptive processes such as biosynthesis, anterograde and retrograde trafficking, and membrane targeting. In pathological conditions, this quality control could lead to the retention of functional VGSC and is therefore the target of different pharmacological approaches...
September 23, 2017: Handbook of Experimental Pharmacology
Jacob M Hull, Lori L Isom
Voltage gated sodium channels (VGSCs) were first identified in terms of their role in the upstroke of the action potential. The underlying proteins were later identified as saxitoxin and scorpion toxin receptors consisting of α and β subunits. We now know that VGSCs are heterotrimeric complexes consisting of a single pore forming α subunit joined by two β subunits; a noncovalently linked β1 or β3 and a covalently linked β2 or β4 subunit. VGSC α subunits contain all the machinery necessary for channel cell surface expression, ion conduction, voltage sensing, gating, and inactivation, in one central, polytopic, transmembrane protein...
September 18, 2017: Neuropharmacology
Maura Casciola, Shu Xiao, Andrei G Pakhomov
Modern technologies enable deep tissue focusing of nanosecond pulsed electric field (nsPEF) for non-invasive nerve and muscle stimulation. However, it is not known if PEF orders of magnitude shorter than the activation time of voltage-gated sodium channels (VGSC) would evoke action potentials (APs). One plausible scenario requires the loss of membrane integrity (electroporation) and resulting depolarization as an intermediate step. We report, for the first time, that the excitation of a peripheral nerve can be accomplished by 12-ns PEF without electroporation...
September 5, 2017: Scientific Reports
Filip Touska, Simon Sattler, Philipp Malsch, Richard J Lewis, Peter W Reeh, Katharina Zimmermann
Ciguatoxins (CTXs) are marine toxins that cause ciguatera fish poisoning, a debilitating disease dominated by sensory and neurological disturbances that include cold allodynia and various painful symptoms as well as long-lasting pruritus. Although CTXs are known as the most potent mammalian sodium channel activator toxins, the etiology of many of its neurosensory symptoms remains unresolved. We recently described that local application of 1 nM Pacific Ciguatoxin-1 (P-CTX-1) into the skin of human subjects induces a long-lasting, painful axon reflex flare and that CTXs are particularly effective in releasing calcitonin-gene related peptide (CGRP) from nerve terminals...
August 30, 2017: Marine Drugs
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