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L-type of voltage-gated Ca2+ channel

Eugen Brailoiu, Christine L Barlow, Servio H Ramirez, Mary E Abood, G Cristina Brailoiu
Platelet-activating factor (PAF) is a potent phospholipid mediator that exerts various pathophysiological effects by interacting with a G protein-coupled receptor. PAF has been reported to increase the permeability of the blood-brain barrier (BBB) via incompletely characterized mechanisms. We investigated the effect of PAF on rat brain microvascular endothelial cells (RBMVEC), a critical component of the BBB. PAF produced a dose-dependent increase in cytosolic Ca2+ concentration; the effect was prevented by the PAF receptor antagonist, WEB2086...
March 6, 2018: Neuroscience
Lifu Sheng, Iryna Leshchyns'ka, Vladimir Sytnyk
The neural cell adhesion molecule 2 (NCAM2) is encoded by a gene on chromosome 21 in humans. NCAM2 accumulates in synapses, but its role in regulation of synapse formation remains poorly understood. We demonstrate that an increase in NCAM2 levels results in increased instability of dendritic protrusions and reduced conversion of protrusions to dendritic spines in mouse cortical neurons. NCAM2 overexpression induces an increase in the frequency of submembrane Ca2+ spikes localized in individual dendritic protrusions and promotes propagation of submembrane Ca2+ spikes over segments of dendrites or the whole dendritic tree...
March 7, 2018: Cerebral Cortex
Edmund Cheung So, Yingwei Wang, Li Qun Yang, Kenny Hsu So, Yi-Ching Lo, Sheng-Nan Wu
GMQ (2-guanidine-4-methylquinazoline or N-(4-methyl-2-quinazolinyl)-guanidine hydrochloride), an agonist of acid-sensing ion channel type 3, has been increasingly used for in vivo studies of alternations in nociceptic behavior. In this study, we tried to investigate whether GMQ has any possible effect on other types of ion channels. Addition of GMQ to pituitary GH3 cells raised the amplitude of Ca2+ -activated K+ currents (IK(Ca) ), which was reversed by verruculogen or PF1022A, but not by TRAM-39. Under inside-out current recordings, addition of GMQ into bath enhanced the probability of large-conductance Ca2+ -activated K+ (BKCa ) channels with an EC50 value of 0...
February 22, 2018: Biochemical Pharmacology
Jens Ingwersen, Lorenzo De Santi, Britta Wingerath, Jonas Graf, Barbara Koop, Reiner Schneider, Christina Hecker, Friederike Schröter, Mary Bayer, Anna Dorothee Engelke, Michael Dietrich, Philipp Albrecht, Hans-Peter Hartung, Pasquale Annunziata, Orhan Aktas, Tim Prozorovski
Multiple sclerosis (MS) is characterized by inflammatory neurodegeneration, with axonal injury and neuronal cell death occurring in parallel to demyelination. Regarding the molecular mechanisms responsible for demyelination and axonopathy, energy failure, aberrant expression of ion channels and excitotoxicity have been suggested to lead to Ca2+ overload and subsequent activation of calcium-dependent damage pathways. Thus, the inhibition of Ca2+ influx by pharmacological modulation of Ca2+ channels may represent a novel neuroprotective strategy in the treatment of secondary axonopathy...
February 23, 2018: Journal of Neurochemistry
Marites T Woon, Pamela A Long, Louise Reilly, Jared M Evans, Alexis M Keefe, Martin R Lea, Carl J Beglinger, Ravi C Balijepalli, Youngsook Lee, Timothy M Olson, Timothy J Kamp
BACKGROUND: Genetic causes of dilated cardiomyopathy (DCM) are incompletely understood. LRRC10 (leucine-rich repeat-containing 10) is a cardiac-specific protein of unknown function. Heterozygous mutations in LRRC10 have been suggested to cause DCM, and deletion of Lrrc10 in mice results in DCM. METHODS AND RESULTS: Whole-exome sequencing was carried out on a patient who presented at 6 weeks of age with DCM and her unaffected parents, filtering for rare, deleterious, recessive, and de novo variants...
February 3, 2018: Journal of the American Heart Association
Fenfen Wu, Marbella Quinonez, Marino DiFranco, Stephen C Cannon
Mutations of CaV1.1, the pore-forming subunit of the L-type Ca2+ channel in skeletal muscle, are an established cause of hypokalemic periodic paralysis (HypoPP). However, functional assessment of HypoPP mutant channels has been hampered by difficulties in achieving sufficient plasma membrane expression in cells that are not of muscle origin. In this study, we show that coexpression of Stac3 dramatically increases the expression of human CaV1.1 (plus α2-δ1b and β1a subunits) at the plasma membrane of Xenopus laevis oocytes...
January 31, 2018: Journal of General Physiology
Sheeja Navakkode, Chao Liu, Tuck Wah Soong
The rapid developments in science have led to an increase in human life expectancy and thus, ageing and age-related disorders/diseases have become one of the greatest concerns in the 21st century. Cognitive abilities tend to decline as we get older. This age-related cognitive decline is mainly attributed to aberrant changes in synaptic plasticity and neuronal connections. Recent studies show that alterations in Ca2+ homeostasis underlie the increased vulnerability of neurons to age-related processes like cognitive decline and synaptic dysfunctions...
March 2018: Ageing Research Reviews
Daisuke Sato, Rose E Dixon, Luis F Santana, Manuel F Navedo
In ventricular myocytes, membrane depolarization during the action potential (AP) causes synchronous activation of multiple L-type CaV1.2 channels (LTCCs), which trigger the release of calcium (Ca2+) from the sarcoplasmic reticulum (SR). This results in an increase in intracellular Ca2+ (Cai) that initiates contraction. During pulsus alternans, cardiac contraction is unstable, going from weak to strong in successive beats despite a constant heart rate. These cardiac alternans can be caused by the instability of membrane potential (Vm) due to steep AP duration (APD) restitution (Vm-driven alternans), instability of Cai cycling (Ca2+-driven alternans), or both, and may be modulated by functional coupling between clustered CaV1...
January 16, 2018: PLoS Computational Biology
Jessica N Peoples, David G Taylor, Alexander N Katchman, Steven N Ebert
Mouse embryos that lack the ability to produce the adrenergic hormones, norepinephrine (NE) and epinephrine (EPI), due to disruption of the dopamine beta-hydroxylase (Dbh-/-) gene inevitably perish from heart failure during mid-gestation. Since adrenergic stimulation is well-known to enhance calcium signaling in developing as well as adult myocardium, and impairments in calcium signaling are typically associated with heart failure, we hypothesized that adrenergic-deficient embryonic hearts would display deficiencies in cardiac calcium signaling relative to adrenergic-competent controls at a developmental stage immediately preceding the onset of heart failure, which first appears beginning or shortly after mouse embryonic day 10...
December 27, 2017: Biochemical and Biophysical Research Communications
Joshua P Whitt, Beth A McNally, Andrea L Meredith
Large conductance K+ (BK) channels are expressed widely in neurons, where their activation is regulated by membrane depolarization and intracellular Ca2+ (Ca2+i). To enable this regulation, BK channels functionally couple to both voltage-gated Ca2+ channels (VGCCs) and channels mediating Ca2+ release from intracellular stores. However, the relationship between BK channels and their specific Ca2+ source for particular patterns of excitability is not well understood. In neurons within the suprachiasmatic nucleus (SCN)-the brain's circadian clock-BK current, VGCC current, and Ca2+i are diurnally regulated, but paradoxically, BK current is greatest at night when VGCC current and Ca2+i are reduced...
December 13, 2017: Journal of General Physiology
U Meza, D Beqollari, R A Bannister
The primary route of Ca2+ entry into cardiac myocytes is via 1,4-dihydropyridine-sensitive, voltage-gated L-type Ca2+ channels. Ca2+ influx through these channels influences duration of action potential and engages excitation-contraction (EC) coupling in both the atria and the myocardium. Members of the RGK (Rad, Rem, Rem2 and Gem/Kir) family of small GTP-binding proteins are potent, endogenously expressed inhibitors of cardiac L-type channels. Although much work has focused on the molecular mechanisms by which RGK proteins inhibit the CaV 1...
December 13, 2017: Acta Physiologica
Kareem Clark, Brooke A Sword, Jeffrey L Dupree
The axon initial segment (AIS), the domain responsible for action potential initiation and maintenance of neuronal polarity, is targeted for disruption in a variety of central nervous system pathological insults. Previous work in our laboratory implicates oxidative stress as a potential mediator of structural AIS alterations in two separate mouse models of central nervous system inflammation, as these effects were attenuated following reactive oxygen species scavenging and NADPH oxidase-2 ablation. While these studies suggest a role for oxidative stress in modulation of the AIS, the direct effects of reactive oxygen and nitrogen species (ROS/RNS) on the stability of this domain remain unclear...
November 2017: ASN Neuro
Daniel S Langfermann, Oliver G Rössler, Gerald Thiel
Stimulation of pancreatic β-cells with glucose activates the protein kinases B-Raf and extracellular signal-regulated protein kinase that participate in glucose sensing. Inhibition of both kinases results in impairment of glucose-regulated gene transcription. To analyze the signaling pathway controlled by B-Raf, we expressed a conditionally active form of B-Raf in INS-1 insulinoma cells. Here, we show that stimulation of B-Raf strongly activated the transcription factor AP-1 which is accompanied by increased c-Jun and c-Fos promoter activities, an upregulation of c-Jun and c-Fos biosynthesis, and elevated transcriptional activation potentials of c-Jun and c-Fos...
December 8, 2017: Molecular and Cellular Endocrinology
Sven Berberich, Jörg Pohle, Marie Pollard, Janet Barroso-Flores, Georg Köhr
Mechanisms underlying information storage have been depicted for global cell-wide and pathway-specific synaptic plasticity. Yet, little is known how these forms of plasticity interact to enhance synaptic competition and network stability. We examined synaptic interactions between apical and basal dendrites of CA1 pyramidal neurons in mouse hippocampal slices. Bursts (50 Hz) of three action potentials (AP-bursts) paired with preceding presynaptic stimulation in stratum radiatum specifically led to LTP of the paired pathway in adult mice (P75)...
December 6, 2017: Scientific Reports
Chike Cao, Yinshi Ren, Adam S Barnett, Anthony J Mirando, Douglas Rouse, Se Hwan Mun, Kyung-Hyun Park-Min, Amy L McNulty, Farshid Guilak, Courtney M Karner, Matthew J Hilton, Geoffrey S Pitt
While the prevalence of osteoporosis is growing rapidly with population aging, therapeutic options remain limited. Here, we identify potentially novel roles for CaV1.2 L-type voltage-gated Ca2+ channels in osteogenesis and exploit a transgenic gain-of-function mutant CaV1.2 to stem bone loss in ovariectomized female mice. We show that endogenous CaV1.2 is expressed in developing bone within proliferating chondrocytes and osteoblasts. Using primary BM stromal cell (BMSC) cultures, we found that Ca2+ influx through CaV1...
November 16, 2017: JCI Insight
Claus Normann, Sibylle Frase, Verena Haug, Gregor von Wolff, Kristin Clark, Patrick Münzer, Alexandra Dorner, Jonas Scholliers, Max Horn, Tanja Vo Van, Gabriel Seifert, Tsvetan Serchov, Knut Biber, Christoph Nissen, Norbert Klugbauer, Josef Bischofberger
BACKGROUND: Long-term synaptic plasticity is a basic ability of the brain to dynamically adapt to external stimuli and regulate synaptic strength and ultimately network function. It is dysregulated by behavioral stress in animal models of depression and in humans with major depressive disorder. Antidepressants have been shown to restore disrupted synaptic plasticity in both animal models and humans; however, the underlying mechanism is unclear. METHODS: We examined modulation of synaptic plasticity by selective serotonin reuptake inhibitors (SSRIs) in hippocampal brain slices from wild-type rats and serotonin transporter (SERT) knockout mice...
October 19, 2017: Biological Psychiatry
Feixue Li, Huihui Ma, Jing Liu
Pyrethroids are a class of widely used insecticides. Cypermethrin (CP) is one of most commonly used pyrethroid insecticides and its residue has been frequently detected in environmental media. Our recent animal study reported that early postnatal exposure to CP induced an increase in serum levels of luteinizing hormone (LH) and follicle-stimulating hormone (FSH) as well as the expression of gonadotropin subunit genes [chorionic gonadotropin α (CGα), LHβ and FSHβ] in pituitary tissues. In this study, we further investigated the precise mechanism by which CP at concentrations of 1-100 nM affected the synthesis of gonadotropins using a murine pituitary gonadotropic cell line LβT2...
November 15, 2017: Toxicological Sciences: An Official Journal of the Society of Toxicology
Yaopeng Hu, Yubin Duan, Ayako Takeuchi, Lin Hai-Kurahara, Jun Ichikawa, Keizo Hiraishi, Tomohiro Numata, Hiroki Ohara, Gentaro Iribe, Michio Nakaya, Masayuki X Mori, Satoshi Matsuoka, Genshan Ma, Ryuji Inoue
Aims: Transient receptor potential cation channel subfamily melastatin member 4 (TRPM4), a Ca2+-activated nonselective cation channel abundantly expressed in the heart, has been implicated in conduction block and other arrhythmic propensities associated with cardiac remodelling and injury. The present study aimed to quantitatively evaluate the arrhythmogenic potential of TRPM4. Methods and results: Patch clamp and biochemical analyses were performed using expression system and an immortalized atrial cardiomyocyte cell line (HL-1), and numerical model simulation was employed...
August 1, 2017: Cardiovascular Research
Ryan C Burke, Sylvia M Bardet, Lynn Carr, Sergii Romanenko, Delia Arnaud-Cormos, Philippe Leveque, Rodney P O'Connor
Nanosecond pulsed electric fields (nsPEFs) have a variety of applications in the biomedical and biotechnology industries. Cancer treatment has been at the forefront of investigations thus far as nsPEFs permeabilize cellular and intracellular membranes leading to apoptosis and necrosis. nsPEFs may also influence ion channel gating and have the potential to modulate cell physiology without poration of the membrane. This phenomenon was explored using live cell imaging and a sensitive fluorescent probe of transmembrane voltage in the human glioblastoma cell line, U87 MG, known to express a number of voltage-gated ion channels...
October 2017: Biochimica et Biophysica Acta
P Rhana, R R Trivelato, P S L Beirão, J S Cruz, A L P Rodrigues
Breast cancer is the most common cancer among women and its metastatic potential is responsible for numerous deaths. Thus, the need to find new targets for improving treatment, and even finding the cure, becomes increasingly greater. Ion channels are known to participate in several physiological functions, such as muscle contraction, cell volume regulation, immune response and cell proliferation. In breast cancer, different types of ion channels have been associated with tumorigenesis. Recently, voltage-gated Na+ channels (VGSC) have been implicated in the processes that lead to increased tumor aggressiveness...
June 5, 2017: Brazilian Journal of Medical and Biological Research, Revista Brasileira de Pesquisas Médicas e Biológicas
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