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potassium homeostasis

Marta Obara-Michlewska, Fengfei Ding, Mariusz Popek, Alexei Verkhratsky, Maiken Nedergaard, Magdalena Zielinska, Jan Albrecht
Acute toxic liver failure (ATLF) rapidly leads to brain oedema and neurological decline. We evaluated the ability of ATLF-affected brain to control the ionic composition and acid-base balance of the interstitial fluid. ATLF was induced in 10-12 weeks old male C57Bl mice by single intraperitoneal (i.p.) injection of 100 μg/g azoxymethane (AOM). Analyses were carried out in cerebral cortex of precomatous mice 20-24 h after AOM administration. Brain fluid status was evaluated by measuring apparent diffusion coefficient [ADC] using NMR spectroscopy, Evans Blue extravasation, and accumulation of an intracisternally-injected fluorescent tracer...
May 14, 2018: Neurochemistry International
Ibrahim Abouelsaad, Sylvie Renault
Jasmonic acid (JA) has been mostly studied in responses to biotic stresses, such as herbivore attack and pathogenic infection. More recently, the involvement of JA in abiotic stresses including salinity was highlighted; yet, its role in salt stress remained unclear. In the current study, we compared the physiological and biochemical responses of wild-type (WT) tomato (Solanum lycopersicum) cv Castlemart and its JA-deficient mutant defenseless-1 (def-1) under salt stress to investigate the role of JA. Plant growth, photosynthetic pigment content, ion accumulation, oxidative stress-related parameters, proline accumulation and total phenolic compounds, in addition to both enzymatic and non-enzymatic antioxidant activities, were measured in both genotypes after 14 days of 100 mM NaCl treatment...
April 21, 2018: Journal of Plant Physiology
Silvia Monticone, Isabel Losano, Martina Tetti, Fabrizio Buffolo, Franco Veglio, Paolo Mulatero
Renin-angiotensin-aldosterone system (RAAS) plays a crucial role in maintaining water and electrolytes homeostasis and its deregulation contributes to the development of arterial hypertension. Since the historical description of the "classical" RAAS, a dramatic increase in our understanding of the molecular mechanisms underlying the development of both essential and secondary hypertension has occurred. Approximatively 25% of the patients affected by arterial hypertension display low renin levels, a definition that is largely arbitrary and depends on the investigated population and the specific characteristics of the assay...
May 14, 2018: Clinical Endocrinology
Mathilde R Rivaud, Antonius Baartscheer, Arie O Verkerk, Leander Beekman, Sridharan Rajamani, Luiz Belardinelli, Connie R Bezzina, Carol Ann Remme
BACKGROUND: Long QT syndrome mutations in the SCN5A gene are associated with an enhanced late sodium current (INa,L ) which may lead to pro-arrhythmic action potential prolongation and intracellular calcium dysregulation. We here investigated the dynamic relation between INa,L , intracellular sodium ([Na+ ]i ) and calcium ([Ca2+ ]i ) homeostasis and pro-arrhythmic events in the setting of a SCN5A mutation. METHODS AND RESULTS: Wild-type (WT) and Scn5a1798insD/+ (MUT) mice (age 3-5 months) carrying the murine homolog of the SCN5A-1795insD mutation on two distinct genetic backgrounds (FVB/N and 129P2) were studied...
July 15, 2018: International Journal of Cardiology
Florence Yellin, Yizeng Li, Varun K A Sreenivasan, Brenda Farrell, Manu B Johny, David Yue, Sean X Sun
Cell volume regulation is fundamentally important in phenomena such as cell growth, proliferation, tissue homeostasis, and embryogenesis. How the cell size is set, maintained, and changed over a cell's lifetime is not well understood. In this work we focus on how the volume of nonexcitable tissue cells is coupled to the cell membrane electrical potential and the concentrations of membrane-permeable ions in the cell environment. Specifically, we demonstrate that a sudden cell depolarization using the whole-cell patch clamp results in a 50% increase in cell volume, whereas hyperpolarization results in a slight volume decrease...
May 8, 2018: Biophysical Journal
Peng Guo, Yi-Ping Qi, Yan-Tong Cai, Tao-Yu Yang, Lin-Tong Yang, Zeng-Rong Huang, Li-Song Chen
Citrus are mainly grown in low pH soils with high active aluminum (Al). 'Xuegan' (Citrus sinensis (L.) Osbeck) and 'Shatian pummelo' (Citrus grandis (L.) Osbeck) seedlings were fertilized for 18 weeks with nutrient solution containing either 0 mM (control) or 1 mM (Al toxicity) AlCl3·6H2O. Aluminum induced decreases of biomass, leaf photosynthesis, relative water content and total soluble protein levels, and increases of methylglyoxal levels only occurred in C. grandis roots and leaves. Besides, the Al-induced decreases of pigments and alterations of chlorophyll a fluorescence transients and fluorescence parameters were greater in C...
April 27, 2018: Tree Physiology
Matheus D Baldissera, Carine F Souza, Débora Seben, Letícia R Sippert, Joseania Salbego, Enio Marchesan, Renato Zanella, Bernardo Baldisserotto, Jaqueline I Golombieski
Thiamethoxam is a neonicotinoid pesticide utilized on a worldwide scale, it has been reported in freshwater ecosystems, and detected in fishery products. Nevertheless, there is a lack of information about thiamethoxam sublethal effects on the gills of freshwater fish, principally linked to energetic metabolism. In this context, creatine kinase (CK) is an enzyme of the phosphoryl transfer network that provides a temporal and spatial energy buffer to maintain cellular energy homeostasis in tissues with high energy requirements, such as gills...
April 27, 2018: Science of the Total Environment
Guillermo E Santa-María, Sonia Oliferuk, Jorge I Moriconi
Since their discovery, twenty years ago, KT-HAK-KUP transporters have become a keystone to understand how alkali cation fluxes are controlled in major land-dwelling photosynthetic organisms. In this review we focus on their discovery, phylogeny, and functions, as well as the regulation of its canonical member, AtHAK5. We also address issues related to structure-function studies, and the technological possibilities opened up by recent findings. Available evidence suggests that this family of transporters underwent an early divergence into major groups following the conquest of land by embryophytes...
April 21, 2018: Journal of Plant Physiology
Christina A Frieder, Scott L Applebaum, T-C Francis Pan, Donal T Manahan
Exogenous environmental factors alter growth rates, yet information remains scant on the biochemical mechanisms and energy trade-offs that underlie variability in the growth of marine invertebrates. Here we study the biochemical bases for differential growth and energy utilization (as adenosine triphosphate [ATP] equivalents) during larval growth of the bivalve Crassostrea gigas exposed to increasing levels of experimental ocean acidification (control, middle, and high pCO2 , corresponding to ∼400, ∼800, and ∼1100 µatm, respectively)...
February 2018: Biological Bulletin
Melanie A Gainey, Joseph W Aman, Daniel E Feldman
Rapid plasticity of layer (L) 2/3 inhibitory circuits is an early step in sensory cortical map plasticity, but its cellular basis is unclear. We show that, in mice of either sex, 1 day whisker deprivation drives rapid loss of L4-evoked feedforward inhibition and more modest loss of feedforward excitation in L2/3 pyramidal (PYR) cells, increasing E-I conductance ratio. Rapid disinhibition was due to reduced L4-evoked spiking by L2/3 parvalbumin (PV) interneurons, caused by reduced PV intrinsic excitability. This included elevated PV spike threshold, associated with an increase in low-threshold, voltage activated delayed rectifier (presumed Kv1) and A-type potassium currents...
April 20, 2018: Journal of Neuroscience: the Official Journal of the Society for Neuroscience
Attilio Marino, Matteo Battaglini, Daniele De Pasquale, Andrea Degl'Innocenti, Gianni Ciofani
A nanotechnology-based approach for the inhibition of breast cancer cell proliferation is proposed. The innovative solution consists in a platform based on biocompatible piezoelectric nanoparticles able to target and remotely stimulate HER2-positive breast cancer cells. The anti-proliferative effects of the ultrasound-driven piezoelectric nanoparticle-assisted stimulation significantly reduced the proliferation by inducing the cell cycle arrest. Similarly to a low-intensity alternating electric field, chronic piezoelectric stimulation resulted able to inhibit cancer cell proliferation by upregulating the expression of the gene encoding Kir3...
April 19, 2018: Scientific Reports
Lise Bankir, Antonio Barbato, Ornella Russo, Gilles Crambert, Roberto Iacone, Nadine Bouby, Ludovica Perna, Pasquale Strazzullo
Plasma potassium concentration (PK ) is tightly regulated. Insulin is known to favor potassium entry into cells. But how potassium leaves the cells later on is not often considered. Previous studies in rats showed that glucagon infusion increased urinary potassium excretion dose-dependently and reversibly. This prompted us to investigate the possible influence of glucagon on potassium handling in humans. We took advantage of the Gly40Ser mutation of the glucagon receptor (GR) that results in a partial loss of function of the GR...
April 2018: Physiological Reports
Jie Xu, Christopher L Bartolome, Cho Shing Low, Xinchi Yi, Cheng-Hao Chien, Peng Wang, Dong Kong
Leptin, a hormone produced in white adipose tissue, acts in the brain to communicate fuel status, suppress appetite following a meal, promote energy expenditure and maintain blood glucose stability1,2 . Dysregulation of leptin or its receptors (LEPR) results in severe obesity and diabetes3-5 . Although intensive studies on leptin have transformed obesity and diabetes research2,6 , clinical applications of the molecule are still limited 7 , at least in part owing to the complexity and our incomplete understanding of the underlying neural circuits...
April 18, 2018: Nature
Mariasavina Severino, Susanna Lualdi, Chiara Fiorillo, Pasquale Striano, Teresa De Toni, Silvio Peluso, Giuseppe De Michele, Andrea Rossi, Mirella Filocamo, Claudio Bruno
BACKGROUND: Epilepsy, ataxia, sensorineural deafness, and tubulopathy (EAST syndrome) is a rare channelopathy due to KCNJ10 mutations. So far, only mild cerebellar hypoplasia and/or dentate nuclei abnormalities have been reported as major neuroimaging findings in these patients. METHODS: We analyzed the clinical and brain MRI features of two unrelated patients (aged 27 and 23 years) with EAST syndrome carrying novel homozygous frameshift mutations (p.Asn232Glnfs*14and p...
April 17, 2018: Journal of Neurology
Marco de Curtis, Laura Uva, Vadym Gnatkovsky, Laura Librizzi
Potassium channels dysfunction and altered genes encoding for molecules involved in potassium homeostasis have been associated with human epilepsy. These observations are in agreement with a control role of extracellular potassium on neuronal excitability and seizure generation. Epileptiform activity, in turn, regulates potassium homeostasis through mechanisms that are still not well established. We review here how potassium-associated processes are regulated in the brain and examine the mechanisms that support the role of potassium in triggering epileptiform activities...
April 10, 2018: Epilepsy Research
Suman Srinivasa, Kathleen V Fitch, Kimberly Wong, Timothy K O'Malley, Patrick Maehler, Karen L Branch, Sara E Looby, Tricia H Burdo, Edgar L Martinez-Salazar, Martin Torriani, Shannon H Lyons, Julian Weiss, Meghan Feldpausch, Takara L Stanley, Gail K Adler, Steven K Grinspoon
Context: HIV-infected individuals demonstrate unique RAAS physiology, with increased RAAS activation in association with visceral adiposity, insulin resistance, and inflammation. A physiologically-based treatment approach targeting mineralocorticoid receptor (MR) blockade may improve metabolic and inflammatory indices in HIV. Objective: To investigate effects of eplerenone on insulin sensitivity, inflammatory indices and other metabolic parameters in HIV. Design: Six month, double-blind, randomized, placebo-controlled trial...
April 5, 2018: Journal of Clinical Endocrinology and Metabolism
Laura Devaux, Dona Sleiman, Maria-Vittoria Mazzuoli, Myriam Gominet, Philippe Lanotte, Patrick Trieu-Cuot, Pierre-Alexandre Kaminski, Arnaud Firon
Cyclic nucleotides are universally used as secondary messengers to control cellular physiology. Among these signalling molecules, cyclic di-adenosine monophosphate (c-di-AMP) is a specific bacterial second messenger recognized by host cells during infections and its synthesis is assumed to be necessary for bacterial growth by controlling a conserved and essential cellular function. In this study, we sought to identify the main c-di-AMP dependent pathway in Streptococcus agalactiae, the etiological agent of neonatal septicaemia and meningitis...
April 16, 2018: PLoS Genetics
Lin Zhang, Guangjie Li, Meng Wang, Dongwei Di, Li Sun, Herbert J Kronzucker, Weiming Shi
The root tip zone is regarded as the principal action site for iron (Fe) toxicity and is more sensitive than other root zones, but the mechanism underpinning this remains largely unknown. We explored the mechanism underpinning the higher sensitivity at the Arabidopsis root tip and elucidated the role of nitric oxide (NO) using NO-related mutants and pharmacological methods. Higher Fe sensitivity of the root tip is associated with reduced potassium (K+ ) retention. NO in root tips is increased significantly above levels elsewhere in the root and is involved in the arrest of primary root tip zone growth under excess Fe, at least in part related to NO-induced K+ loss via SNO1 (sensitive to nitric oxide 1)/SOS4 (salt overly sensitive 4) and reduced root tip zone cell viability...
April 15, 2018: New Phytologist
Lena Trifonov, Michal Afri, Krzysztof Palczewski, Edward E Korshin, Arie Gruzman
BACKGROUND: Apelin receptor (APJ) is a G protein-coupled receptor (GPCR) activated by the endogenous peptide apelin. The apelin-APJ system has emerged as an important regulator of cardiovascular homeostasis. Recently, a potent benzimidazole-derived apelin peptidomimetic, CMF-019, was patented but without a comprehensive description of its synthesis and a complete spectroscopic characterization of the intermediates. OBJECTIVE: Here, a detailed preparation of CMF-019 through a modified and improved synthetic pathway is described...
April 12, 2018: Medicinal Chemistry
Fabian M Commichau, Jörg Stülke
Cyclic di-AMP is an important second messenger in bacteria. In most firmicutes, the molecule is required for growth in complex media, but also toxic upon accumulation. In the current issue of Journal of Bacteriology, Zarrella and coworkers present a suppressor analysis of a Streptococcus pneumoniae strain that is unable to degrade c-di-AMP (T. M. Zarrella, D. W. Metzger, and G. Bai, J Bacteriol 200:e00045-18, 2018, The study identifies new links between c-di-AMP and potassium homeostasis and supports the hypothesis that c-di-AMP serves as a second messenger to report about the intracellular potassium concentrations...
April 2, 2018: Journal of Bacteriology
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