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Voltage-gated calcium channels

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https://www.readbyqxmd.com/read/28744923/the-role-of-t-type-calcium-channels-in-the-subiculum-to-burst-or-not-to-burst
#1
Srdjan M Joksimovic, Pierce Eggan, Yukitoshi Izumi, Sonja Lj Joksimovic, Vesna Tesic, Robert M Dietz, James E Orfila, Michael R DiGruccio, Paco S Herson, Vesna Jevtovic-Todorovic, Charles F Zorumski, Slobodan M Todorovic
Several studies suggest that voltage-gated calcium currents are involved in generating high frequency burst firing in the subiculum, but the exact nature of these currents remains unknown. Here, we used selective pharmacology, molecular and genetic approaches to implicate Cav3.1-containing T-channels in subicular burst firing, in contrast to several previous reports discounting T-channels as major contributors to subicular neuron physiology. Furthermore, pharmacological antagonism of T-channels completely suppressed development of long-term potentiation (LTP) in the CA1-subiculum, but not in the CA3-CA1 pathway...
July 26, 2017: Journal of Physiology
https://www.readbyqxmd.com/read/28742147/genetic-analysis-of-the-regulation-of-the-voltage-gated-calcium-channel-homolog-cch1-by-the-%C3%AE-subunit-homolog-ecm7-and-cortical-er-protein-scs2-in-yeast
#2
Takafumi Kato, Aya Kubo, Tatsuya Nagayama, Shinichiro Kume, Chikara Tanaka, Yoshitaka Nakayama, Kazuko Iida, Hidetoshi Iida
The yeast Cch1/Mid1 Ca2+ channel is equivalent to animal voltage-gated Ca2+ channels and activated in cells incubated in low Ca2+ medium. We herein investigated the third subunit, Ecm7, under the same cell culture conditions. The deletion of ECM7 slightly lowered Ca2+ influx activity in the CNB1+ background, in which calcineurin potentially dephosphorylates Cch1, but markedly lowered this activity in the cnb1Δ background. The deletion of the C-terminal cytoplasmic region of Ecm7 also reduced Ca2+ influx activity...
2017: PloS One
https://www.readbyqxmd.com/read/28739256/palmitoylation-of-ca-2-channel-subunit-cav%C3%AE-2a-induces-pancreatic-beta-cell-toxicity-via-ca-2-overload
#3
Abdulla S Kazim, Petter Storm, Enming Zhang, Erik Renström
High blood glucose triggers the release of insulin from pancreatic beta cells, but if chronic, causes cellular stress, partly due to impaired Ca(2+) homeostasis. Ca(2+) influx is controlled by voltage-gated calcium channels (CaV) and high density of CaV in the plasma membrane could lead to Ca(2+) overload. Trafficking of the pore-forming CaVα1 subunit to the plasma membrane is regulated by auxiliary subunits, such as the CaVβ2a subunit. This study investigates, using Ca(2+) imaging and immunohistochemistry, the role of palmitoylation of CaVβ2a in maintaining Ca(2+) homeostasis and beta cell function...
July 21, 2017: Biochemical and Biophysical Research Communications
https://www.readbyqxmd.com/read/28734867/p-q-type-voltage-gated-calcium-channels-mediate-the-ethanol-and-crf-sensitivity-of-central-amygdala-gabaergic-synapses
#4
F P Varodayan, M L Logrip, M Roberto
The central amygdala (CeA) GABAergic system is hypothesized to drive the development of alcohol dependence, due to its pivotal roles in the reinforcing actions of alcohol and the expression of negative emotion, anxiety and stress. Recent work has also identified an important role for the CeA corticotropin-releasing factor (CRF) system in the interaction between anxiety/stress and alcohol dependence. We have previously shown that acute alcohol and CRF each increase action potential-independent GABA release in the CeA via their actions at presynaptic CRF type 1 receptors (CRF1s); however, the shared mechanism employed by these two compounds requires further investigation...
July 19, 2017: Neuropharmacology
https://www.readbyqxmd.com/read/28734073/differential-calcium-sensitivity-in-nav-1-5-mixed-syndrome-mutants
#5
Mena Abdelsayed, Alban-Elouen Baruteau, Karen Gibbs, Shubhayan Sanatani, Andrew D Krahn, Vincent Probst, Peter C Ruben
INTRODUCTION: Inherited arrhythmias may arise from mutations in the SCN5a gene, which encodes the cardiac voltage-gated sodium channel, NaV 1.5. Mutants in NaV 1.5 result in Brugada Syndrome (BrS1), Long-QT Syndrome (LQT3), or mixed syndromes (an overlap of BrS1/LQT3). Exercise is a potential arrhythmogenic trigger in mixed syndromes. We sought to determine the effects of elevated cytosolic calcium, common during exercise, in mixed syndrome NaV 1.5 mutants. METHODS: We used whole-cell patch-clamp to assess the biophysical properties of NaV 1...
July 22, 2017: Journal of Physiology
https://www.readbyqxmd.com/read/28733226/allatoregulatory-like-systems-and-changes-in-cytosolic-ca-2-modulate-feeding-behaviour-in-hydra
#6
María Eugenia Alzugaray, Jorge Rafael Ronderos
Allatotropin (AT) and allatostatin-C (AST-C) are neuropeptides originally characterized by their ability to modulate the secretion of juvenile hormones in insects. Beyond the allatoregulatory function, these neuropeptides are pleiotropic acting as myoregulators not only in insects, but also in other groups of invertebrates. We have previously proposed the existence of AT and AST-C like systems in Hydra sp., a member of the phylum Cnidaria, which is a basal group of Metazoa, sharing a common ancestor with Bilateria...
July 18, 2017: General and Comparative Endocrinology
https://www.readbyqxmd.com/read/28731153/altered-profile-of-mrna-expression-in-atrioventricular-node-of-streptozotocin%C3%A2-induced-diabetic-rats
#7
Frank Christopher Howarth, Khatija Parekh, Petrilla Jayaprakash, Edward Samuel Inbaraj, Murat Oz, Halina Dobrzynski, Thomas Edward Adrian
Prolonged action potential duration, reduced action potential firing rate, upstroke velocity and rate of diastolic depolarization have been demonstrated in atrioventricular node (AVN) cells from streptozotocin (STZ)‑induced diabetic rats. To further clarify the molecular basis of these electrical disturbances, the mRNA profiles encoding a variety of proteins associated with the generation and conduction of electrical activity in the AVN, were evaluated in the STZ‑induced diabetic rat heart. Expression of mRNA was measured in AVN biopsies using reverse transcription‑quantitative polymerase chain reaction techniques...
July 20, 2017: Molecular Medicine Reports
https://www.readbyqxmd.com/read/28728818/mechanosensitive-piezo-channels-in-the-gastrointestinal-tract
#8
C Alcaino, G Farrugia, A Beyder
Sensation of mechanical forces is critical for normal function of the gastrointestinal (GI) tract and abnormalities in mechanosensation are linked to GI pathologies. In the GI tract there are several mechanosensitive cell types-epithelial enterochromaffin cells, intrinsic and extrinsic enteric neurons, smooth muscle cells and interstitial cells of Cajal. These cells use mechanosensitive ion channels that respond to mechanical forces by altering transmembrane ionic currents in a process called mechanoelectrical coupling...
2017: Current Topics in Membranes
https://www.readbyqxmd.com/read/28726567/possible-mechanisms-involved-in-the-anti-nociceptive-effects-of-hydro-ethanolic-leaf-extract-of-ziziphus-abyssinica
#9
Eric Boakye-Gyasi, Isaac Tabiri Henneh, Wonder Kofi Mensah Abotsi, Elvis Ofori Ameyaw, Eric Woode
CONTEXT: Various parts of Ziziphus abyssinica Hochst ex. A. Rich (Rhamnaceae) have been used in Ghanaian and African traditional medicine as an analgesic. However, there are little scientific data to support the anti-nociceptive effects of the hydro-ethanolic leaf extract of Ziziphus abyssinica (EthE) as well as the possible mechanisms involved in its anti-nociceptive effects. PURPOSE: To predict possible nociceptive pathways involved in the anti-nociceptive effects of EthE...
December 2017: Pharmaceutical Biology
https://www.readbyqxmd.com/read/28726541/characterization-of-postsynaptic-calcium-signals-in-the-pyramidal-neurons-of-anterior-cingulate-cortex
#10
Xu-Hui Li, Qian Song, Tao Chen, Min Zhuo
Calcium signaling is critical for synaptic transmission and plasticity. N-methyl-D-aspartic acid (NMDA) receptors play a key role in synaptic potentiation in the anterior cingulate cortex. Most previous studies of calcium signaling focus on hippocampal neurons, little is known about the activity-induced calcium signals in the anterior cingulate cortex. In the present study, we show that NMDA receptor-mediated postsynaptic calcium signals induced by different synaptic stimulation in anterior cingulate cortex pyramidal neurons...
January 2017: Molecular Pain
https://www.readbyqxmd.com/read/28715135/chronic-pharmacological-blockade-of-the-na-ca-2-exchanger-modulates-the-growth-and-development-of-the-purkinje-cell-dendritic-arbor-in-mouse-cerebellar-slice-cultures
#11
Pradeep Sherkhane, Josef P Kapfhammer
The Na(+) /Ca(2+) exchanger (NCX) is a bi-directional plasma membrane antiporter involved in Ca(2+) homeostasis in eukaryotes. NCX has three isoforms, NCX1-3, and all of them are expressed in the cerebellum. Immunostaining on cerebellar slice cultures indicates that NCX is widely expressed in the cerebellum, including expression in Purkinje cells. The pharmacological blockade of the forward mode of NCX (Ca(2+) efflux mode) by Bepridil moderately inhibited growth and development of Purkinje cell dendritic arbor in cerebellar slice cultures...
July 17, 2017: European Journal of Neuroscience
https://www.readbyqxmd.com/read/28711685/misunderstandings-and-controversies-about-the-insulin-secreting-properties-of-antidiabetic-sulfonylureas
#12
REVIEW
Jean-Claude Henquin
After 60 years of use in the treatment of type 2 diabetes, hypoglycemic sulfonylureas remain a recommended option in current therapeutic charts. Their binding to sulfonylurea receptor-1, the regulatory subunit of ATP-sensitive potassium channels in the plasma membrane of pancreatic β-cells, leads to closure of the channels, membrane depolarization and influx of Ca(2+) through voltage-gated calcium channels. The resulting increase in cytosolic Ca(2+) triggers exocytosis of insulin granules. Sulfonylureas and glucose thus produce the same triggering signal but, unlike sulfonylureas, glucose does so via acceleration of β-cell metabolism...
July 12, 2017: Biochimie
https://www.readbyqxmd.com/read/28711494/development-of-membrane-ion-channels-during-neural-differentiation-from-human-embryonic-stem-cells
#13
Sara Mirsadeghi, Ebrahim Shahbazi, Katayoun Hemmesi, Shiva Nemati, Hossein Baharvand, Javad Mirnajafi-Zadeh, Sahar Kiani
OBJECTIVE: For human embryonic stem cells (hESCs) to differentiate into neurons, enormous changes has to occur leading to trigger action potential and neurotransmitter release. We attempt to determine the changes in expression of voltage gated channels (VGCs) and their electrophysiological properties during neural differentiation. MATERIALS AND METHODS: The relative expressions of α-subunit of voltage gated potassium, sodium and calcium channels were characterized by qRT-PCR technique...
July 12, 2017: Biochemical and Biophysical Research Communications
https://www.readbyqxmd.com/read/28701749/calcium-activated-sk-channels-control-firing-regularity-by-modulating-sodium-channel-availability-in-midbrain-dopamine-neurons
#14
Rajeshwari Iyer, Mark A Ungless, Aldo A Faisal
Dopamine neurons in the substantia nigra pars compacta and ventral tegmental area regulate behaviours such as reward-related learning, and motor control. Dysfunction of these neurons is implicated in Schizophrenia, addiction to drugs, and Parkinson's disease. While some dopamine neurons fire single spikes at regular intervals, others fire irregular single spikes interspersed with bursts. Pharmacological inhibition of calcium-activated potassium (SK) channels increases the variability in their firing pattern, sometimes also increasing the number of spikes fired in bursts, indicating that SK channels play an important role in maintaining dopamine neuron firing regularity and burst firing...
July 12, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28696432/cross-disorder-risk-gene-cacna1c-differentially-modulates-susceptibility-to-psychiatric-disorders-during-development-and-adulthood
#15
N Dedic, M L Pöhlmann, J S Richter, D Mehta, D Czamara, M W Metzger, J Dine, B T Bedenk, J Hartmann, K V Wagner, A Jurik, L M Almli, A Lori, S Moosmang, F Hofmann, C T Wotjak, G Rammes, M Eder, A Chen, K J Ressler, W Wurst, M V Schmidt, E B Binder, J M Deussing
Single-nucleotide polymorphisms (SNPs) in CACNA1C, the α1C subunit of the voltage-gated L-type calcium channel Cav1.2, rank among the most consistent and replicable genetics findings in psychiatry and have been associated with schizophrenia, bipolar disorder and major depression. However, genetic variants of complex diseases often only confer a marginal increase in disease risk, which is additionally influenced by the environment. Here we show that embryonic deletion of Cacna1c in forebrain glutamatergic neurons promotes the manifestation of endophenotypes related to psychiatric disorders including cognitive decline, impaired synaptic plasticity, reduced sociability, hyperactivity and increased anxiety...
July 11, 2017: Molecular Psychiatry
https://www.readbyqxmd.com/read/28693898/nanosecond-pulsed-electric-fields-depolarize-transmembrane-potential-via-voltage-gated-k-ca-2-and-trpm8-channels-in-u87-glioblastoma-cells
#16
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...
July 7, 2017: Biochimica et Biophysica Acta
https://www.readbyqxmd.com/read/28677751/effects-of-rmf-on-bkca-and-kv-channels-in-basilar-arterial-smooth%C3%A2-muscle-cells-of-shr
#17
Yan-Fei Qian, Yang Wang, Wei-Wei Tian, Sheng Wang, Lei Zhao, Li Li, Ke-Tao Ma, Jun-Qiang Si
The current study observed the effects and investigated the mechanism of remifentanil (RMF) on the isolated cerebral basilar arteries of spontaneously hypertensive rats (SHR) and Wistar‑Kyoto (WKY) rats. A pressure myograph system was used to observe and compare the effects of different concentrations of RMF (10‑10‑10‑5 mol/l) on the diameter changes of freshly isolated cerebral basilar arteries, which have been pre‑shrunk by phenylephrine (PE), an endothelium‑independent vasoconstrictor. Vascular smooth‑muscle cells of the cerebral basilar artery (BASMCs) were freshly obtained via enzymolysis...
September 2017: Molecular Medicine Reports
https://www.readbyqxmd.com/read/28672269/underlying-mechanisms-preserving-coronary-basal-tone-and-no-mediated-relaxation-in-obesity-involvement-of-%C3%AE-1-subunit-mediated-upregulation-of-bkca-channels
#18
Belén Climent, Ana Sánchez, Laura Moreno, Francisco Pérez-Vizcaíno, Albino García-Sacristán, Luis Rivera, Dolores Prieto
BACKGROUND AND AIMS: The impact of obesity on vasomotor regulation of coronary arteries and its underlying mechanisms are not completely understood and, in particular, the role of BKCa channels in the NO-mediated coronary vasodilation in obesity remains to be elucidated. METHODS: The effects of selective blockade of BKCa channel was tested on nitric oxide (NO)-mediated vasodilator responses of coronary arteries from lean and obese Zucker rats (LZR and OZR, respectively) by means of simultaneous measurements of intracellular Ca(2+) concentration ([Ca(2+)]i) by Fura-2 fluorescence and tension in endothelium-denuded coronary arteries mounted in microvascular myographs...
June 23, 2017: Atherosclerosis
https://www.readbyqxmd.com/read/28669898/relevance-of-tissue-specific-subunit-expression-in-channelopathies
#19
REVIEW
Hartwig Seitter, Alexandra Koschak
Channelopathies are a diverse group of human disorders that are caused by mutations in genes coding for ion channels or channel-regulating proteins. Several dozen channelopathies have been identified that involve both non-excitable cells as well as electrically active tissues like brain, skeletal and smooth muscle or the heart. In this review, we start out from the general question which ion channel genes are expressed tissue-selectively. We mined the human gene expression database Human Protein Atlas (HPA) for tissue-enriched ion channel genes and found 85 genes belonging to the ion channel families...
June 29, 2017: Neuropharmacology
https://www.readbyqxmd.com/read/28667054/analysis-of-decreases-in-systemic-arterial-pressure-and-heart-rate-in-response-to-the-hydrogen-sulfide-donor-sodium-sulfide
#20
Kevin W Swan, Bryant Minkyu Song, Allen L Chen, Travis J Chen, Ryan A Chan, Bradley T Guidry, Prasad V G Katakam, Edmund K Kerut, Thomas D Giles, Philip Kadowitz
The actions of hydrogen sulfide (H2S) on the heart and vasculature have been extensively reported. However, the mechanisms underlying the effects of H2S are unclear in the anesthetized rat. The objective of the current study is to investigate the effect of H2S on the electrocardiogram and examine the relationship between H2S-induced changes in heart rate (HR), mean arterial pressure (MAP), and respiratory function. Intravenous (iv) administration of the H2S donor sodium sulfide (Na2S) in the anesthetized Sprague-Dawley (SD) rat decreased MAP and HR and produced changes in respiratory function...
June 30, 2017: American Journal of Physiology. Heart and Circulatory Physiology
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