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Calcium channels

François Seghers, Xavier Yerna, Nadège Zanou, Olivier Devuyst, Rudi Vennekens, Bernd Nilius, Philippe Gailly
The renin - angiotensin system is a crucial blood pressure regulation system. It consists of a hormonal cascade where the rate-limiting enzyme is renin, which is secreted in blood flow by renal juxtaglomerular (JG) cells in response to low pressure in the renal afferent arteriole. In contrast, an increase in blood pressure results in a decreased renin secretion. This is accompanied by a transitory increase in [Ca(2+) ]i of JG cells. The inverse relationship between [Ca(2+) ]i and renin secretion has been called the "calcium paradox" of renin release...
October 25, 2016: Journal of Physiology
Chia-Wen Hsu, Jui-Hua Hsieh, Ruili Huang, Dirk Pijnenburg, Thai Khuc, Jon Hamm, Jinghua Zhao, Caitlin Lynch, Rinie van Beuningen, Xiaoqing Chang, Rene Houtman, Menghang Xia
Chemicals that alter normal function of farnesoid X receptor (FXR) have been shown to affect the homeostasis of bile acids, glucose, and lipids. Several structural classes of environmental chemicals and drugs that modulated FXR transactivation were previously identified by quantitative high-throughput screening (qHTS) of the Tox21 10K chemical collection. In the present study, we validated the FXR antagonist activity of selected structural classes, including avermectin anthelmintics, dihydropyridine calcium channel blockers, 1,3-indandione rodenticides, and pyrethroid pesticides, using in vitro assay and quantitative structural-activity relationship (QSAR) analysis approaches...
October 20, 2016: Toxicology and Applied Pharmacology
George L Bakris, John M Burkart, Eric D Weinhandl, Peter A McCullough, Michael A Kraus
Hypertension is a cardinal feature of end-stage renal disease (ESRD). Hypertensive nephropathy is the primary cause of ESRD for nearly 30% of patients, and the prevalence of hypertension is >85% in new patients with ESRD. In contemporary hemodialysis (HD) patients, mean predialysis systolic blood pressure (SBP) is nearly 150mmHg, and about 70%, 50%, and 40% use β-blockers, calcium channel blockers, and renin-angiotensin system inhibitors, respectively. Predialysis SBP generally exhibits a U-shaped association with mortality risk...
November 2016: American Journal of Kidney Diseases: the Official Journal of the National Kidney Foundation
Kirilka Mladenova, Svetla D Petrova, Tonya D Andreeva, Veselina Moskova-Doumanova, Tanya Topouzova-Hristova, Yuri Kalvachev, Konstantin Balashev, Shomi S Bhattacharya, Christina Chakarova, Zdravko Lalchev, Jordan A Doumanov
Human bestrophin-1 (hBest1) is a transmembrane calcium-activated chloride channel protein - member of the bestrophin family of anion channels, predominantly expressed in the membrane of retinal pigment epithelium (RPE) cells. Mutations in the protein cause ocular diseases, named Bestrophinopathies. Here, we present the first Fourier transform infrared (FTIR) study of the secondary structure elements of hBest1, π/A isotherms and hysteresis, Brewster angle microscopy (BAM) and atomic force microscopy (AFM) visualization of the aggregation state of protein molecules dispersed as Langmuir and Langmuir-Blodgett films...
October 13, 2016: Colloids and Surfaces. B, Biointerfaces
Junting Huang, Gerald W Zamponi
Calcium entry via voltage gated calcium channels mediates a wide range of physiological functions, whereas calcium channel dysregulation has been associated with numerous pathophysiological conditions. There are myriad cell signaling pathways that act on voltage gated calcium channels to fine tune their activities and to regulate their cell surface expression. These regulatory mechanisms include the activation of G protein-coupled receptors and downstream phosphorylation events, and their control over calcium channel trafficking through direct physical interactions...
October 18, 2016: Current Opinion in Pharmacology
Katrin Feldbauer, Jan Schlegel, Juliane Weissbecker, Frank Sauer, Phillip G Wood, Ernst Bamberg, Ulrich Terpitz
An optochemokine tandem was developed to control the release of calcium from endosomes into the cytosol by light and to analyze the internalization kinetics of G-protein coupled receptors (GPCRs) by electrophysiology. A previously constructed rhodopsin tandem was re-engineered to combine the light-gated Ca2+-permeable cation channel Channelrhodopsin-2(L132C), CatCh, with the chemokine receptor CXCR4 in a functional tandem protein tCXCR4/CatCh. The GPCR was used as a shuttle protein to displace CatCh from the plasma membrane into intracellular areas...
2016: PloS One
Benoîte Bourdin, Emilie Segura, Marie-Philippe Tétreault, Sylvie Lesage, Lucie Parent
Inherited or de novo mutations in cation-selective channels may lead to sudden cardiac death. Alteration in the plasma membrane trafficking of these multi-spanning transmembrane proteins, with or without change in channel gating, is often postulated to contribute significantly in this process. It has thus become critical to develop a method to quantify the change of the relative cell surface expression of cardiac ion channels on a large scale. Herein, a detailed protocol is provided to determine the relative total and cell surface expression of cardiac L-type calcium channels CaV1...
September 28, 2016: Journal of Visualized Experiments: JoVE
Derek Garden, Arianna Rinaldi, Matthew F Nolan
The inferior olive plays a critical role in motor coordination and learning by integrating diverse afferent signals to generate climbing fibre inputs to the cerebellar cortex. While it is well established that climbing fibre signals are important for motor coordination, the mechanisms by which neurones in the inferior olive integrate synaptic inputs and the roles of particular ion channels are unclear. Here, we test the hypothesis that neurones in the inferior olive actively integrate glutamatergic synaptic inputs...
October 21, 2016: Journal of Physiology
Alessandro Rubini, Vincenzo Catena, Daniele Del Monte, Gerardo Bosco
CONTEXT: Calcium channel blockers may theoretically exhibit relaxing effects not only on vascular smooth muscle but also on airway smooth muscle. OBJECTIVE: To investigate possible effects of nifedipine on respiratory mechanics in the rat. METHODS: Respiratory system mechanical parameters were measured by the end-inflation occlusion method in the rat in vivo before and after the intraperitoneal administration of nifedipine. RESULTS: We found that nifedipine affects respiratory mechanics, inducing a reduction of airway resistance and of respiratory system elastance, probably because of a relaxing action on airway and parenchimal smooth muscle cells...
October 21, 2016: Journal of Enzyme Inhibition and Medicinal Chemistry
Young Joon Kwon, Marni J Falk, Michael J Bennett
CLN3 disease (Spielmeyer-Vogt-Sjogren-Batten disease, previously known as classic juvenile neuronal ceroid lipofuscinosis, NCL) is a pediatric-onset progressive neurodegenerative disease characterized by progressive vision loss, seizures, loss of cognitive and motor function, and early death. While no precise biochemical mechanism or therapies are known, the pathogenesis of CLN3 disease involves intracellular calcium accumulation that may trigger apoptosis. Our prior work in in vitro cell models of CLN3 deficiency suggested that FDA-approved calcium channel antagonists may have therapeutic value...
October 20, 2016: Journal of Inherited Metabolic Disease
Stefano Fiorucci, Angela Zampella, Giuseppe Cirino, Mariarosaria Bucci, Eleonora Distrutti
Bile acids are end product of cholesterol metabolism generated in the liver and released in the intestine. In addition to their role in nutrient absorption, bile acids are increasingly recognized as regulatory signals which exert their function beyond the intestine by activating a network of membrane and nuclear receptors. The best characterized of these bile acid activated receptors, GPBAR1 (also known as TGR5) and the Farnesosid-x-receptor (FXR) have also been detected in the vascular system and their activation mediate the vasodilatory effects of bile acids in the systemic and splanchnic circulation...
October 7, 2016: American Journal of Physiology. Heart and Circulatory Physiology
Jay S Naik, Jessica M Osmond, Benjimen R Walker, Nancy L Kanagy
Hydrogen sulfide (H2S) is a recently described gaseous vasodilator produced within the vasculature by the enzymes cystathionine γ-lyase and 3-mercaptopyruvate sulfurtansferase. Previous data demonstrate that endothelial cells (EC) are the source of endogenous H2S production and are required for H2S-induced dilation. However, the signal transduction pathway activated by H2S within EC has not been elucidated. TRPV4 and large conductance Ca(2+)-activated K channels (BK channels) are expressed in EC. H2S-induced dilation is inhibited by luminal administration of iberiotoxin and disruption of the endothelium...
October 7, 2016: American Journal of Physiology. Heart and Circulatory Physiology
Donal Melanaphy, Christpher D Johnson, Maxim Kustov, Connall Watson, Lyudmyla Borysova, Theodore Burdyga, Alexander V Zholos
Transient receptor potential melastatin 8 (TRPM8) is the principal cold and menthol receptor channel. Characterized primarily for its cold sensing role in sensory neurons, it is expressed and functional in several non-neuronal tissues, including vasculature. We previously demonstrated that menthol causes vasoconstriction and vasodilatation in isolated arteries, depending on vascular tone. Here we investigated calcium's role in responses mediated by TRPM8 ligands in rat tail artery myocytes using patch-clamp electrophysiology and ratiometric Ca(2+) recording...
October 7, 2016: American Journal of Physiology. Heart and Circulatory Physiology
Sheng-Jie Shiue, Chi-Hsu Wang, Tao-Yeuan Wang, Yi-Chun Chen, Jen-Kun Cheng
OBJECTIVE: T-type channel (TCC) CaV3.2 plays a pivotal role in pain transmission. In this study, we examined the effects of intrathecal TCC blockers on CaV3.2 expression in a L5/6 spinal nerve ligation (SNL) pain model. The neurotoxicity of TCC blockers were also evaluated. METHODS: Male Sprague-Dawley rats (200-250 g) were used for right L5/6 SNL to induce neuropathic pain. Intrathecal infusion of saline or TCC blockers [mibefradil (0.7 μg/h) or ethosuximide (60 μg/h)] was started after surgery for 7 days...
October 17, 2016: Acta Anaesthesiologica Taiwanica: Official Journal of the Taiwan Society of Anesthesiologists
Jing Zhang, You Wang, Kai-Ming Sun, Kuan Fang, Xuexi Tang
Polybrominated diphenyl ethers (PBDEs) are widely dispersed persistent organic pollutants in the marine ecosystem. However, their toxic mechanisms in marine organisms, especially invertebrates, remain poorly understood. Two common congeners of PBDEs, tetrabrominated diphenyl ether-47 (BDE-47) and decabrominated diphenyl ether-209 (BDE-209), were investigated. Their toxic mechanisms, with a focus on oxidative stress, were examined in rotifer Brachionus plicatilis. Overproduction of reactive oxygen species (ROS) was induced by two PBDEs...
October 17, 2016: Marine Pollution Bulletin
Tao Hou, Weiwei Liu, Wen Shi, Zhili Ma, Hui He
The structure of the desalted duck egg white peptides-calcium chelate was characterized by fluorescence spectroscopy, fourier transform infrared spectroscopy, and dynamic light scattering. Characterization results showed structural folding and aggregation of amino acids or oligopeptides during the chelation process. Desalted duck egg white peptides enhanced the calcium uptake in the presence of oxalate, phosphate and zinc ions in Caco-2 monolayers. Animal model indicated that desalted duck egg white peptides effectively enhanced the mineral absorption and counteracted the deleterious effects of phytic acid...
March 15, 2017: Food Chemistry
Jessica M Meves, Binhai Zheng
In this issue of Neuron, Tedeschi et al. (2016) describe the voltage-gated calcium channel subunit alpha2delta2 as a developmental switch from axon elongation to synapse formation and transmission that doubles as a suppressor of axon regeneration, providing a molecular clue for the synaptic stabilization hypothesis of CNS regeneration failure.
October 19, 2016: Neuron
Alice C Wyse-Jackson, Sarah L Roche, Ana M Ruiz-Lopez, Jennifer N Moloney, Ashleigh M Byrne, Thomas G Cotter
Retinitis pigmentosa (RP) is a degenerative retinal disease leading to photoreceptor cell loss. In 2011, our group identified the synthetic progesterone 'Norgestrel' as a potential treatment for RP. Subsequent research showed Norgestrel to work through progesterone receptor membrane component 1 (PGRMC1) activation and upregulation of neuroprotective basic fibroblast growth factor (bFGF). Using trophic factor deprivation of 661W photoreceptor-like cells, we aimed to further elucidate the mechanism leading to Norgestrel-induced neuroprotection...
October 20, 2016: European Journal of Neuroscience
Rajeev B Tajhya, Xueyou Hu, Mark R Tanner, Redwan Huq, Natee Kongchan, Joel R Neilson, George G Rodney, Frank T Horrigan, Lubov T Timchenko, Christine Beeton
Myoblasts are mononucleated precursors of myofibers; they persist in mature skeletal muscles for growth and regeneration post injury. During myotonic dystrophy type 1 (DM1), a complex autosomal-dominant neuromuscular disease, the differentiation of skeletal myoblasts into functional myotubes is impaired, resulting in muscle wasting and weakness. The mechanisms leading to this altered differentiation are not fully understood. Here, we demonstrate that the calcium- and voltage-dependent potassium channel, KCa1...
October 20, 2016: Cell Death & Disease
Lubica Lacinova, Norbert Weiss
No abstract text is available yet for this article.
October 2016: General Physiology and Biophysics
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