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https://www.readbyqxmd.com/read/28620187/discovery-and-identification-of-o-o-diethyl-o-4-5-phenyl-4-5-dihydroisoxazol-3-yl-phenyl-phosphorothioate-xp-1408-as-a-novel-mode-of-action-of-organophosphorus-insecticides
#1
Zhigang Zeng, Ying Yan, Bingfeng Wang, Niu Liu, Hanhong Xu
Organophosphorus (OP) insecticides play an important role in pest control. Many OP insecticides have been removed from the market because of their high toxicity to humans. We designed and synthesized a new OP insecticide with the goal of providing a low cost, and less toxic insecticide. The mode of action of O, O-diethyl O-(4-(5-phenyl-4, 5-dihydroisoxazol-3-yl) phenyl) phosphorothioate (XP-1408) was studied in Drosophila melanogaster. Bioassays showed that XP-1408 at a concentration of 50 mg/L delayed larval development...
June 15, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28607094/pharmacology-of-the-nav1-1-domain-iv-voltage-sensor-reveals-coupling-between-inactivation-gating-processes
#2
Jeremiah D Osteen, Kevin Sampson, Vivek Iyer, David Julius, Frank Bosmans
The Nav1.1 voltage-gated sodium channel is a critical contributor to excitability in the brain, where pathological loss of function leads to such disorders as epilepsy, Alzheimer's disease, and autism. This voltage-gated sodium (Nav) channel subtype also plays an important role in mechanical pain signaling by primary afferent somatosensory neurons. Therefore, pharmacologic modulation of Nav1.1 represents a potential strategy for treating excitability disorders of the brain and periphery. Inactivation is a complex aspect of Nav channel gating and consists of fast and slow components, each of which may involve a contribution from one or more voltage-sensing domains...
June 12, 2017: Proceedings of the National Academy of Sciences of the United States of America
https://www.readbyqxmd.com/read/28597987/trafficking-and-localization-to-the-plasma-membrane-of-nav-1-5-promoted-by-the-%C3%AE-2-subunit-is-defective-due-to-a-%C3%AE-2-mutation-associated-with-brugada-syndrome
#3
Gemma Dulsat, Sonia Palomeras, Eric Cortada, Helena Riuró, Ramon Brugada, Marcel Vergés
BACKGROUND INFORMATION: Cardiac channelopathies arise by mutations in genes encoding ion channel subunits. One example is Brugada Syndrome (BrS), which causes arrhythmias and sudden death. BrS is often associated with mutations in SCN5A, encoding Nav 1.5, the α subunit of the major cardiac voltage-gated sodium channel. This channel forms a protein complex including one or two associated β subunits as well as other proteins. RESULTS: We analyzed regulation of Nav 1...
June 9, 2017: Biology of the Cell
https://www.readbyqxmd.com/read/28591687/mtor-mediated-na-ca-2-exchange-affects-cell-proliferation-and-metastasis-of-melanoma-cells
#4
Yi Yang, Zhanpeng Luo, Yonghong Hao, Wei Ba, Rui Wang, Wenjuan Wang, Xiangyu Ding, Chengxin Li
Melanoma is a common malignant tumor, which is associated with high mortality rate. The multiple-drug resistance of tumor cells often results in failure of chemotherapy. The aim of our study is to investigate the expression of Nav 1.6 in human melanoma cells and human epidermal melanocytes. Additionally, the effect of Na+channels on Ca+ current and mTOR activity in melanoma cells were also analyzed. The protein expression levels of Nav1.6 in human melanocyte PIG1, WM266 and WM115 cells were investigated by western blot...
June 4, 2017: Biomedicine & Pharmacotherapy, Biomédecine & Pharmacothérapie
https://www.readbyqxmd.com/read/28560448/multiple-nav1-5-isoforms-are-functionally-expressed-in-the-brain-and-present-distinct-expression-patterns-compared-with-cardiac-nav1-5
#5
Jun Wang, Shao-Wu Ou, Yun-Fei Bai, Yun-Jie Wang, Zhi-Qing David Xu, Guo-Ming Luan
It has previously been demonstrated that there are various voltage gated sodium channel (Nav) 1.5 splice variants expressed in brain tissue. A total of nine Nav1.5 isoforms have been identified, however, the potential presence of further Nav1.5 variants expressed in brain neurons remains to be elucidated. The present study systematically investigated the expression of various Nav1.5 splice variants and their associated electrophysiological properties in the rat brain tissue, via biochemical analyses and whole‑cell patch clamp recording...
July 2017: Molecular Medicine Reports
https://www.readbyqxmd.com/read/28557626/response-characteristics-and-retinal-origin-of-the-photopic-negative-response-of-the-electroretinogram-in-dogs
#6
Shunsuke Takada, Junzo Kinoshita, Noriaki Iwata, Masako Imaoka, Yoshiro Tani
PURPOSE: To investigate the response characteristics and retinal origin of the photopic negative response (PhNR) of the electroretinograms (ERGs) in dogs. METHODS: Photopic ERGs were elicited by white flash stimuli of different intensities under a steady white background illumination in four anesthetized dogs. These ERGs were also recorded in the same manner after intravitreal injection of tetrodotoxin (TTX). Additionally, retinal localization of voltage-gated sodium channel Nav 1...
May 30, 2017: Current Eye Research
https://www.readbyqxmd.com/read/28557294/a-mechanism-for-nav-1-5-downregulation-and-sodium-current-decrease-in-heart-failure
#7
EDITORIAL
Sara Pagans, Marcel Vergés
The pore-forming α-subunit of the cardiac voltage-gated sodium channel, NaV 1.5, is responsible for the initial upstroke of the cardiac action potential. NaV 1.5 cell surface expression and function are modulated by its interaction with regulatory proteins and by posttranslational modifications, such as phosphorylation, arginine methylation or ubiquitination (1) . Genetic mutations in the SCN5A gene, which encodes NaV 1.5, have been associated with a variety of inherited cardiac arrhythmias, including long QT syndrome type 3, Brugada syndrome, atrial fibrillation, and congenital sick sinus syndrome...
May 30, 2017: Acta Physiologica
https://www.readbyqxmd.com/read/28542706/modulatory-features-of-the-novel-spider-toxin-%C3%AE-trtx-df1a-isolated-from-the-venom-of-the-spider-davus-fasciatus
#8
Fernanda C Cardoso, Zoltan Dekan, Jennifer J Smith, Jennifer R Deuis, Irina Vetter, Volker Herzig, Paul F Alewood, Glenn F King, Richard J Lewis
BACKGROUND AND PURPOSE: Naturally occurring dysfunction in NaV channels results in complex disorders such as chronic pain, making these channels an attractive target for new therapies. In the pursuit of novel NaV modulators, we investigated spider venoms for new inhibitors of NaV channels. EXPERIMENTAL APPROACH: We used high-throughput screens to identify a NaV modulator in venom of the spider Davus fasciatus. Further characterization of this venom peptide was undertaken using fluorescent and electrophysiological assays, molecular modeling and a rodent pain model...
May 24, 2017: British Journal of Pharmacology
https://www.readbyqxmd.com/read/28534438/the-axonal-cytoskeleton-and-the-assembly-of-nodes-of-ranvier
#9
Aniket Ghosh, Diane L Sherman, Peter J Brophy
Vertebrate nervous systems rely on rapid nerve impulse transmission to support their complex functions. Fast conduction depends on ensheathment of nerve axons by myelin-forming glia and the clustering of high concentrations of voltage-gated sodium channels (Nav) in the axonal gaps between myelinated segments. These gaps are the nodes of Ranvier. Depolarization of the axonal membrane initiates the action potential responsible for impulse transmission, and the Nav help ensure that this is restricted to nodes...
May 1, 2017: Neuroscientist: a Review Journal Bringing Neurobiology, Neurology and Psychiatry
https://www.readbyqxmd.com/read/28530638/sodium-channel-nav1-9-mutations-associated-with-insensitivity-to-pain-dampen-neuronal-excitability
#10
Jianying Huang, Carlos G Vanoye, Alison Cutts, Y Paul Goldberg, Sulayman D Dib-Hajj, Charles J Cohen, Stephen G Waxman, Alfred L George
Voltage-gated sodium channel (NaV) mutations cause genetic pain disorders that range from severe paroxysmal pain to a congenital inability to sense pain. Previous studies on NaV1.7 and NaV1.8 established clear relationships between perturbations in channel function and divergent clinical phenotypes. By contrast, studies of NaV1.9 mutations have not revealed a clear relationship of channel dysfunction with the associated and contrasting clinical phenotypes. Here, we have elucidated the functional consequences of a NaV1...
May 22, 2017: Journal of Clinical Investigation
https://www.readbyqxmd.com/read/28522250/ppargamma-agonists-rescue-increased-phosphorylation-of-fgf14-at-s226-in-the-tg2576-mouse-model-of-alzheimer-s-disease
#11
Wei-Chun J Hsu, Norelle C Wildburger, Sigmund J Haidacher, Miroslav N Nenov, Oluwarotimi Folorunso, Aditya K Singh, Brent C Chesson, Whitney F Franklin, Ibdanelo Cortez, Rovshan G Sadygov, Kelly T Dineley, Jay S Rudra, Giulio Taglialatela, Cheryl F Lichti, Larry Denner, Fernanda Laezza
BACKGROUND: Cognitive impairment in humans with Alzheimer's disease (AD) and in animal models of Aβ-pathology can be ameliorated by treatments with the nuclear receptor peroxisome proliferator-activated receptor-gamma (PPARγ) agonists, such as rosiglitazone (RSG). Previously, we demonstrated that in the Tg2576 animal model of AD, RSG treatment rescued cognitive deficits and reduced aberrant activity of granule neurons in the dentate gyrus (DG), an area critical for memory formation...
May 15, 2017: Experimental Neurology
https://www.readbyqxmd.com/read/28522215/blocking-voltage-gated-sodium-channels-as-a-strategy-to-suppress-pathological-cough
#12
REVIEW
Hui Sun, Marian Kollarik, Bradley J Undem
Pathological cough is thought to be secondary to inappropriate activation of vagal sensory nerves. Sensory nerves can be activated by a large number of disparate stimuli. The most relevant stimuli to block for effective anti-tussive therapy likely depend on the specific underlying pathology that is leading to the coughing. Blocking voltage-gated sodium channels (NaV) will prevent action potential initiation and conduction and therefore prevent sensory communication between the airways and brainstem. In so doing, they would be expected to inhibit evoked cough independently of the nature of the stimulus and underlying pathology...
May 15, 2017: Pulmonary Pharmacology & Therapeutics
https://www.readbyqxmd.com/read/28503166/inhibition-of-ectopic-arginine-vasopressin-production-by-phenytoin-in-the-small-cell-lung-cancer-cell-line-lu-165
#13
Takahiro Ohta, Mitsuo Mita, Shigeru Hishinuma, Reiko Ishii-Nozawa, Kazuhisa Takahashi, Masaru Shoji
Phenytoin, a voltage-gated sodium channel (NaV channel) antagonist, reportedly inhibits arginine vasopressin (AVP) release from an isolated rat neurohypophysis. So far, it is uncertain whether phenytoin has a direct action on ectopic AVP-producing neuroendocrine tumors. We studied the effect of phenytoin on the release of copeptin, the C-terminal fragment of pro-AVP, and expression of AVP gene in the human small cell lung cancer cell line Lu-165. Cells were maintained in RPMI1640 medium with 10% fetal bovine serum and were used within the fifth passage...
2017: Frontiers in Endocrinology
https://www.readbyqxmd.com/read/28497266/an-insecticidal-toxin-from-nephila-clavata-spider-venom
#14
Lin Jin, Mingqian Fang, Mengrou Chen, Chunling Zhou, Rose Ombati, Md Abdul Hakim, Guoxiang Mo, Ren Lai, Xiuwen Yan, Yumin Wang, Shilong Yang
Spiders are the most successful insect predators given that they use their venom containing insecticidal peptides as biochemical weapons for preying. Due to the high specificity and potency of peptidic toxins, discoveries of insecticidal toxins from spider venom have provided an opportunity to obtain natural compounds for agricultural applications without affecting human health. In this study, a novel insecticidal toxin (μ-NPTX-Nc1a) was identified and characterized from the venom of Nephila clavata. Its primary sequence is GCNPDCTGIQCGWPRCPGGQNPVMDKCVSCCPFCPPKSAQG which was determined by automated Edman degradation, cDNA cloning, and MS/MS analysis...
May 11, 2017: Amino Acids
https://www.readbyqxmd.com/read/28481659/ion-channel-mechanisms-underlying-frequency-firing-patterns-of-the-avian-nucleus-magnocellularis-a-computational-model
#15
Ting Lu, Kirstie Wade, Hui Hong, Jason Tait Sanchez
We have previously shown that late-developing avian nucleus magnocellularis (NM) neurons (embryonic [E] days 19-21) fire action potentials (APs) that resembles a band-pass filter in response to sinusoidal current injections of varying frequencies. NM neurons located in the mid- to high-frequency regions of the nucleus fire preferentially at 75 Hz, but only fire a single onset AP to frequency inputs greater than 200 Hz. Surprisingly, NM neurons do not fire APs to sinusoidal inputs less than 20 Hz regardless of the strength of the current injection...
May 8, 2017: Channels
https://www.readbyqxmd.com/read/28475112/insect-active-toxins-with-promiscuous-pharmacology-from-the-african-theraphosid-spider-monocentropus-balfouri
#16
Jennifer J Smith, Volker Herzig, Maria P Ikonomopoulou, Sławomir Dziemborowicz, Frank Bosmans, Graham M Nicholson, Glenn F King
Many chemical insecticides are becoming less efficacious due to rising resistance in pest species, which has created much interest in the development of new, eco-friendly bioinsecticides. Since insects are the primary prey of most spiders, their venoms are a rich source of insect-active peptides that can be used as leads for new bioinsecticides or as tools to study molecular receptors that are insecticidal targets. In the present study, we isolated two insecticidal peptides, µ/ω-TRTX-Mb1a and -Mb1b, from venom of the African tarantula Monocentropus balfouri...
May 5, 2017: Toxins
https://www.readbyqxmd.com/read/28473457/pharmacologic-characterization-of-amg8379-a-potent-and-selective-small-molecule-sulfonamide-antagonist-of-the-voltage-gated-sodium-channel-nav1-7
#17
Thomas J Kornecook, Ruoyuan Yin, Stephen Altmann, Xuhai Be, Virginia Berry, Christopher P Ilch, Michael Jarosh, Danielle Johnson, Josie H Lee, Sonya G Lehto, Joseph Ligutti, Dong Liu, Jason Luther, David Matson, Danny Ortuno, John Roberts, Kristin Taborn, Jinti Wang, Matthew M Weiss, Violeta Yu, Dawn X D Zhu, Robert T Fremeau, Bryan D Moyer
Potent and selective antagonists of the voltage-gated sodium channel NaV1.7 represent a promising avenue for the development of new chronic pain therapies. We generated a small molecule atropisomer quinolone sulfonamide antagonist AMG8379 and a less active enantiomer AMG8380. Here we show that AMG8379 potently blocks human NaV1.7 channels with an IC50 of 8.5 nM and endogenous tetrodotoxin (TTX)-sensitive sodium channels in dorsal root ganglion (DRG) neurons with an IC50 of 3.1 nM in whole-cell patch clamp electrophysiology assays using a voltage protocol that interrogates channels in a partially inactivated state...
July 2017: Journal of Pharmacology and Experimental Therapeutics
https://www.readbyqxmd.com/read/28469558/intracellular-fibroblast-growth-factor-14-emerging-risk-factor-for-brain-disorders
#18
REVIEW
Jessica Di Re, Paul A Wadsworth, Fernanda Laezza
The finely tuned regulation of neuronal firing relies on the integrity of ion channel macromolecular complexes. Minimal disturbances of these tightly regulated networks can lead to persistent maladaptive plasticity of brain circuitry. The intracellular fibroblast growth factor 14 (FGF14) belongs to the nexus of proteins interacting with voltage-gated Na+ (Nav) channels at the axonal initial segment. Through isoform-specific interactions with the intracellular C-terminal tail of neuronal Nav channels (Nav1.1, Nav1...
2017: Frontiers in Cellular Neuroscience
https://www.readbyqxmd.com/read/28450535/sodium-channel-nav1-8-underlies-ttx-resistant-axonal-action-potential-conduction-in-somatosensory-c-fibers-of-distal-cutaneous-nerves
#19
Amanda H Klein, Alina Vyshnevska, Timothy V Hartke, Roberto De Col, Joseph L Mankowski, Brian Turnquist, Frank Bosmans, Peter W Reeh, Martin Schmelz, Richard W Carr, Matthias Ringkamp
Voltage-gated sodium (NaV) channels are responsible for the initiation and conduction of action potentials within primary afferents. The nine NaV channel isoforms recognized in mammals are often functionally divided into tetrodotoxin (TTX)-sensitive (TTX-s) channels (NaV1.1-NaV1.4, NaV1.6-NaV1.7) that are blocked by nanomolar concentrations and TTX-resistant (TTX-r) channels (NaV1.8 and NaV1.9) inhibited by millimolar concentrations, with NaV1.5 having an intermediate toxin sensitivity. For small-diameter primary afferent neurons, it is unclear to what extent different NaV channel isoforms are distributed along the peripheral and central branches of their bifurcated axons...
May 17, 2017: Journal of Neuroscience: the Official Journal of the Society for Neuroscience
https://www.readbyqxmd.com/read/28440808/automated-and-manual-patch-clamp-data-of-human-induced-pluripotent-stem-cell-derived-dopaminergic-neurons
#20
Denise Franz, Hervør Lykke Olsen, Oliver Klink, Jan Gimsa
Human induced pluripotent stem cells can be differentiated into dopaminergic neurons (Dopa.4U). Dopa.4U neurons expressed voltage-gated NaV and KV channels and showed neuron-like spontaneous electrical activity. In automated patch clamp measurements with suspended Dopa.4U neurons, delayed rectifier K(+) current (delayed KV) and rapidly inactivating A-type K(+) current (fast KV) were identified. Examination of the fast KV current with inhibitors yielded IC50 values of 0.4 mM (4-aminopyridine) and 0.1 mM (tetraethylammonium)...
April 25, 2017: Scientific Data
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