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Voltage-dependent calcium channels

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https://www.readbyqxmd.com/read/28442324/the-interactive-role-of-cb1-receptors-and-l-type-calcium-channels-in-hippocampal-long-term-potentiation-in-rats
#1
Hamidreza Komaki, Fargol Saadat, Siamak Shahidi, Abdolrahman Sarihi, Parisa Hasanein, Alireza Komaki
'Long-term potentiation (LTP) of synaptic responses is a widely researched model of synaptic plasticity that occurs during learning and memory. The cannabinoid system is an endogenous system that modulate this kind of synaptic plasticity. In addition, voltage dependent calcium channels is essential for induction of LTP at some synapses in the hippocampus. However, there is currently debate over the interaction between L-type calcium channels and cannabinoid system on the synaptic plasticity. In this study, we examined the effects of an acute administration of the cannabinoid antagonist AM251 following a chronic administration of the Ca(2+) channel blocker verapamil on LTP induction in the hippocampal dentate gyrus(DG) of rats...
April 22, 2017: Brain Research Bulletin
https://www.readbyqxmd.com/read/28439241/nifedipine-inhibition-of-high-voltage-activated-calcium-channel-currents-in-cerebral-artery-myocytes-is-influenced-by-extracellular-divalent-cations
#2
Fei Wang, Masayo Koide, George C Wellman
Voltage-dependent calcium channels (VDCCs) play an essential role in regulating cerebral artery diameter and it is widely appreciated that the L-type VDCC, CaV1.2, encoded by the CACNA1C gene, is a principal Ca(2+) entry pathway in vascular myocytes. However, electrophysiological studies using 10 mM extracellular barium ([Ba(2+)]o) as a charge carrier have shown that ~20% of VDCC currents in cerebral artery myocytes are insensitive to 1,4-dihydropyridine (1,4-DHP) L-type VDDC inhibitors such as nifedipine. Here, we investigated the hypothesis that the concentration of extracellular divalent cations can influence nifedipine inhibition of VDCC currents...
2017: Frontiers in Physiology
https://www.readbyqxmd.com/read/28438566/t-type-voltage-gated-calcium-channels-are-involved-in-endothelium-dependent-relaxation-of-mice-pulmonary-artery
#3
Guillaume Gilbert, Arnaud Courtois, Mathilde Dubois, Laure-Anne Cussac, Thomas Ducret, Philippe Lory, Roger Marthan, Jean-Pierre Savineau, Jean-François Quignard
In pulmonary arterial endothelial cells, Ca(2+) channels and intracellular Ca(2+)concentration ([Ca(2+)]i) control the release of vasorelaxant factors such as nitric oxide and are involved in the regulation of pulmonary arterial blood pressure. The present study was undertaken to investigate the implication of T-type voltage-gated Ca(2+)channels (T-VGCCs, Cav3.1 channel) in the endothelium-dependent relaxation of intrapulmonary arteries. Relaxation was quantified by means of a myograph in wild type and Cav3...
April 21, 2017: Biochemical Pharmacology
https://www.readbyqxmd.com/read/28421035/antiepileptic-drugs-impair-shortening-of-isolated-cardiomyocytes
#4
Johanna Hulbert, Christian E Elger, Rainer Meyer, Rainer Surges
BACKGROUND: Most antiepileptic drugs (AEDs) inhibit seizure generation by acting on voltage-dependent ion channels. Voltage-dependent sodium and calcium channels are commonly expressed in brain and heart, suggesting that AEDs may have considerable cardiodepressive effects, thereby facilitating sudden cardiac death as a potential cause of sudden unexpected death in epilepsy. Here, we investigated the effects of carbamazepine (CBZ), lamotrigine (LTG), and levetiracetam (LEV) alone and in combination on the shortening properties of isolated ventricular cardiomyocytes of wild-type mice...
2017: Frontiers in Neurology
https://www.readbyqxmd.com/read/28419410/selective-and-state-dependent-activation-of-tresk-background-potassium-channel-by-cloxyquin
#5
Miklós Lengyel, Alice Dobolyi, Gábor Czirják, Péter Enyedi
BACKGROUND AND PURPOSE: Cloxyquin (5-cloroquinolin-8-ol) has been previously described as an activator of TRESK (K2P 18.1, TWIK-related spinal cord K(+) channel) background potassium channel. We have examined the specificity of the drug by testing several K2P channels. We have investigated the mechanism of cloxyquin-mediated TRESK activation, focusing on the differences between the physiologically relevant regulatory states of the channel. EXPERIMENTAL APPROACH: Potassium currents were measured by two-electrode voltage clamp in Xenopus oocytes and by whole-cell patch clamp in mouse dorsal root ganglion (DRG) neurons...
April 18, 2017: British Journal of Pharmacology
https://www.readbyqxmd.com/read/28406893/the-chemical-basis-for-electrical-signaling
#6
REVIEW
William A Catterall, Goragot Wisedchaisri, Ning Zheng
Electrical signals generated by minute currents of ions moving across cell membranes are central to all rapid processes in biology. Initiation and propagation of electrical signals requires voltage-gated sodium (NaV) and calcium (CaV) channels. These channels contain a tetramer of membrane-bound subunits or domains comprising a voltage sensor and a pore module. Voltage-dependent activation occurs as membrane depolarization drives outward movements of positive gating changes in the voltage sensor via a sliding-helix mechanism, which leads to a conformational change in the pore module that opens its intracellular activation gate...
April 13, 2017: Nature Chemical Biology
https://www.readbyqxmd.com/read/28398555/biophysical-and-functional-characterization-of-hippocalcin-mutants-responsible-for-human-dystonia
#7
Nordine Helassa, Svetlana V Antonyuk, Lu-Yun Lian, Lee P Haynes, Robert D Burgoyne
Dystonia is a neurological movement disorder that forces the body into twisting, repetitive movements or sometimes painful abnormal postures. With the advent of next-generation sequencing technologies, the homozygous mutations T71N and A190T in the neuronal calcium sensor (NCS) hippocalcin were identified as the genetic cause of primary isolated dystonia (DYT2 dystonia). However, the effect of these mutations on the physiological role of hippocalcin has not yet been elucidated. Using a multidisciplinary approach, we demonstrated that hippocalcin oligomerises in a calcium-dependent manner and binds to voltage-gated calcium channels...
April 7, 2017: Human Molecular Genetics
https://www.readbyqxmd.com/read/28384108/profiling-of-circulating-serum-micrornas-in-children-with-autism-spectrum-disorder-using-stem-loop-qrt-pcr-assay
#8
Tatyana M Kichukova, Nikolay T Popov, Ivan S Ivanov, Tihomir I Vachev
BACKGROUND: Development of biomarkers for autism spectrum disorder (ASD) has still remained a challenge to date. Recently, alterations of the expression of microRNAs (miRNAs) in peripheral blood, serum and post-mortem brain tissue have been linked to ASD. miRNAs are known to be secreted by various cell types and can mediate transmission of information into recipient cells and to modulate their physiological functions. On this basis it is assumed that circulating miRNAs could be useful biomarkers for the diagnosis or prognosis of pathological conditions...
March 1, 2017: Folia Medica
https://www.readbyqxmd.com/read/28383826/ptdins-4-5-p2-pip2-modulates-afterhyperpolarizations-in-oxytocin-neurons-of-the-supraoptic-nucleus
#9
Matthew K Kirchner, Robert C Foehring, Lie Wang, Giri Kumar Chandaka, Joseph C Callaway, William E Armstrong
Oxytocin- (OT) and vasopressin- (VP) secreting magnocellular neurons of the supraoptic nucleus (SON) display calcium-dependent afterhyperpolarizations (AHPs) following a train of action potentials that are critical to shaping the firing patterns of these cells. Previous work demonstrated that the lipid phosphatidylinositol 4,5-bisphosphate (PIP2 ) enabled the slow AHP component (sAHP) in cortical pyramidal neurons. We investigated whether this phenomenon occurred in OT and VP neurons of the SON. Using whole cell recordings in coronal hypothalamic slices from adult female rats, we demonstrated that inhibition of PIP2 synthesis with wortmannin robustly blocked both the ImAHP and IsAHP of OT, but not VP neurons with high affinity...
April 6, 2017: Journal of Physiology
https://www.readbyqxmd.com/read/28375602/the-marine-guanidine-alkaloid-crambescidin-816-induces-calcium-influx-and-cytotoxicity-in-primary-cultures-of-cortical-neurons-through-glutamate-receptors
#10
Aida G Mendez, Andrea Boente Juncal, Siguara B L Silva, Olivier P Thomas, Víctor Martín Vázquez, Amparo Alfonso, Mercedes R Vieytes, Carmen Vale, Luís M Botana
Crambescidin 816 is a guanidine alkaloid produced by the sponge Crambe crambe with known antitumoral activity. While the information describing the effects of this alkaloid in central neurons is scarce, Cramb816 is known to block voltage dependent calcium channels being selective for L-type channels. Moreover, Cramb816 reduced neuronal viability through an unknown mechanism. Here, we aimed to describe the toxic activity of Cramb816 in cortical neurons. Since calcium influx is considered the main mechanism responsible for neuronal cell death, the effects of Cramb816 in the cytosolic calcium concentration of cortical neurons were studied...
April 24, 2017: ACS Chemical Neuroscience
https://www.readbyqxmd.com/read/28374528/calcium-activated-bkca-channels-govern-dynamic-membrane-depolarizations-of-horizontal-cells-in-rodent-retina
#11
Xiaoping Sun, Arlene A Hirano, Nicholas C Brecha, Steven Barnes
Large conductance, calcium-activated potassium (BKCa ) channels have numerous roles in neurons including the regulation of membrane excitability, intracellular [Ca(2+) ] regulation, and neurotransmitter release. In the retina, they have been identified in photoreceptors, bipolar cells, amacrine cells, and ganglion cells, but have not been conclusively identified in mammalian horizontal cells. We found that outward current recorded between -30 mV and +60 mV is carried primarily in BKCa channels in isolated horizontal cells of rats and mice...
April 4, 2017: Journal of Physiology
https://www.readbyqxmd.com/read/28373283/distinct-domains-of-the-%C3%AE-1-subunit-cytosolic-n-terminus-control-surface-expression-and-functional-properties-of-large-conductance-calcium-activated-potassium-bk-channels
#12
Lie Chen, Danlei Bi, Zen Huat Lu, Heather McClafferty, Michael J Shipston
The properties and function of large conductance calcium- and voltage- activated potassium (BK) channels are modified by the tissue specific expression of regulatory β 1-subunits. Although the short cytosolic N-terminal domain of the β 1-subunit is important for controlling both BK channel trafficking and function, whether the same, or different, regions of the N-terminus control these distinct processes remain unknown. Here we demonstrate that the first six N-terminal residues, including K3, K4 and L5, are critical for controlling functional regulation, but not trafficking, of BK channels...
April 3, 2017: Journal of Biological Chemistry
https://www.readbyqxmd.com/read/28369952/a-calcium-dependent-pathway-underlies-activity-dependent-plasticity-of-electrical-synapses-in-the-thalamic-reticular-nucleus
#13
Jessica Sevetson, Sarah Fittro, Emily Heckman, Julie S Haas
Recent results have demonstrated modification of electrical synapse strength by varied forms of neuronal activity. However, the mechanisms underlying plasticity induction in central mammalian neurons are unclear. Here we show that the two established inductors of plasticity at electrical synapses in the thalamic reticular nucleus - paired burst spiking in coupled neurons, and mGluR-dependent tetanization of synaptic input - are separate pathways that converge at a common downstream endpoint. Using occlusion experiments and pharmacology in patched pairs of coupled neurons in vitro, we show that burst-induced depression depends on calcium entry via voltage-gated channels, is blocked by BAPTA chelation, and recruits intracellular calcium release on its way to activation of phosphatase activity...
March 29, 2017: Journal of Physiology
https://www.readbyqxmd.com/read/28363981/alcohol-dependence-disrupts-amygdalar-l-type-voltage-gated-calcium-channel-mechanisms
#14
Florence P Varodayan, Giordano de Guglielmo, Marian L Logrip, Olivier George, Marisa Roberto
L-type voltage-gated calcium channels (LTCCs) are implicated in several psychiatric disorders that are co-morbid with alcoholism and involve amygdala dysfunction. Within the amygdala, the central nucleus (CeA) is critical in acute alcohol's reinforcing actions, and its dysregulation in human alcoholics drives their negative emotional state and motivation to drink. Here we investigated the specific role of CeA LTCCs in the effects of acute alcohol at the molecular, cellular physiology and behavioral levels, and their potential neuroadaptation in alcohol-dependent rats...
March 31, 2017: Journal of Neuroscience: the Official Journal of the Society for Neuroscience
https://www.readbyqxmd.com/read/28348377/bilirubin-augments-ca-2-load-of-developing-bushy-neurons-by-targeting-specific-subtype-of-voltage-gated-calcium-channels
#15
Min Liang, Xin-Lu Yin, Hai-Bo Shi, Chun-Yan Li, Xin-Yi Li, Ning-Ying Song, Hao-Song Shi, Yi Zhao, Lu-Yang Wang, Shan-Kai Yin
Neonatal brain is particularly vulnerable to pathological levels of bilirubin which elevates and overloads intracellular Ca(2+), leading to neurotoxicity. However, how voltage-gated calcium channels (VGCCs) are functionally involved in excess calcium influx remains unknown. By performing voltage-clamp recordings from bushy cells in the ventral cochlear nucleus (VCN) in postnatal rat pups (P4-17), we found the total calcium current density was more than doubled over P4-17, but the relative weight of VGCC subtypes changed dramatically, being relatively equal among T, L, N, P/Q and R-type at P4-6 to predominantly L, N, R over T and P/Q at P15-17...
March 27, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28348186/biological-rationale-and-potential-clinical-use-of-gabapentin-and-pregabalin-in-bipolar-disorder-insomnia-and-anxiety-protocol-for-a-systematic-review-and-meta-analysis
#16
Kerensa T Houghton, Alexandra Forrest, Amine Awad, Lauren Z Atkinson, Sarah Stockton, Paul J Harrison, John R Geddes, Andrea Cipriani
INTRODUCTION: Gabapentin has been extensively prescribed off-label for psychiatric indications, with little established evidence of efficacy. Gabapentin and pregabalin, a very similar drug with the same mechanism of action, bind to a subunit of voltage-dependent calcium channels which are implicated in the aetiopathogenesis of bipolar disorder, anxiety and insomnia. This systematic review and meta-analysis aims to collect and critically appraise all the available evidence about the efficacy and tolerability of gabapentin and pregabalin in the treatment of bipolar disorder, insomnia and anxiety...
March 27, 2017: BMJ Open
https://www.readbyqxmd.com/read/28346321/growth-arrest-and-dna-damage-inducible-protein-45%C3%AE-mediated-dna-demethylation-of-voltage-dependent-t-type-calcium-channel-3-2-subunit-enhances-neuropathic-allodynia-after-nerve-injury-in-rats
#17
Cheng-Yuan Lai, Ming-Chun Hsieh, Yu-Cheng Ho, An-Sheng Lee, Hsueh-Hsiao Wang, Jen-Kun Cheng, Yat-Pang Chau, Hsien-Yu Peng
BACKGROUND: Growth arrest and DNA-damage-inducible protein 45β reactivates methylation-silenced neural plasticity-associated genes through DNA demethylation. However, growth arrest and DNA-damage-inducible protein 45β-dependent demethylation contributes to neuropathic allodynia-associated spinal plasticity remains unclear. METHODS: Adult male Sprague-Dawley rats (654 out of 659) received a spinal nerve ligation or a sham operation with or without intrathecal application of one of the following: growth arrest and DNA-damage-inducible protein 45β messenger RNA-targeted small interfering RNA, lentiviral vector expressing growth arrest and DNA-damage-inducible protein 45β, Ro 25-6981 (an NR2B-bearing N-methyl-D-aspartate receptor antagonist), or KN-93 (a calmodulin-dependent protein kinase II antagonist) were used for behavioral measurements, Western blotting, immunofluorescence, dot blots, detection of unmodified cytosine enrichment at cytosine-phosphate-guanine site, chromatin immunoprecipitation quantitative polymerase chain reaction analysis, and slice recordings...
March 27, 2017: Anesthesiology
https://www.readbyqxmd.com/read/28343066/calcium-triggers-reversal-of-calmodulin-on-nested-anti-parallel-sites-in-the-iq-motif-of-the-neuronal-voltage-dependent-sodium-channel-nav1-2
#18
Liam Hovey, C Andrew Fowler, Ryan Mahling, Zesen Lin, Mark Stephen Miller, Dagan C Marx, Jesse B Yoder, Elaine H Kim, Kristin M Tefft, Brett C Waite, Michael D Feldkamp, Liping Yu, Madeline A Shea
Several members of the voltage-gated sodium channel family are regulated by calmodulin (CaM) and ionic calcium. The neuronal voltage-gated sodium channel NaV1.2 contains binding sites for both apo (calcium-depleted) and calcium-saturated CaM. We have determined equilibrium dissociation constants for rat NaV1.2 IQ motif [IQRAYRRYLLK] binding to apo CaM (~3nM) and (Ca(2+))4-CaM (~85nM), showing that apo CaM binding is favored by 30-fold. For both apo and (Ca(2+))4-CaM, NMR demonstrated that NaV1.2 IQ motif peptide (NaV1...
March 9, 2017: Biophysical Chemistry
https://www.readbyqxmd.com/read/28336549/eavk-segment-c-sequence-confers-ca-2-dependent-changes-to-the-kinetics-of-full-length-human-ano1
#19
Peter R Strege, Simon J Gibbons, Amelia Mazzone, Cheryl E Bernard, Arthur Beyder, Gianrico Farrugia
Anoctamin1 (Ano1, TMEM16A) is a calcium-activated chloride channel specifically expressed in interstitial cells of Cajal (ICC) of the gastrointestinal (GI) tract muscularis propria. Ano1 is necessary for normal electrical slow waves and ICC proliferation. The full length human Ano1 sequence includes an additional exon, exon "0," at the N-terminus. Ano1 with exon "0" (Ano1(0)) had a lower EC50 for intracellular calcium ([Ca(2+)]i) and faster chloride current (ICl) kinetics. The Ano1 alternative splice variant with segment "c" encoding exon 13 expresses on the first intracellular loop four additional amino acid residues, EAVK, which alter ICl at low [Ca(2+)]i Exon 13 is expressed in 75-100% of Ano1 transcripts in most human tissues but only 25% in human stomach...
March 23, 2017: American Journal of Physiology. Gastrointestinal and Liver Physiology
https://www.readbyqxmd.com/read/28322832/dapoxetine-induces-neuroprotective-effects-against-glutamate-induced-neuronal-cell-death-by-inhibiting-calcium-signaling-and-mitochondrial-depolarization-in-cultured-rat-hippocampal-neurons
#20
Imju Jeong, Ji Seon Yang, Yi Jae Hong, Hee Jung Kim, Sang June Hahn, Shin Hee Yoon
Selective serotonin reuptake inhibitors (SSRIs) have an inhibitory effect on various ion channels including Ca(2+) channels. We used fluorescent dye-based digital imaging, whole-cell patch clamping and cytotoxicity assays to examine whether dapoxetine, a novel rapid-acting SSRI, affect glutamate-induced calcium signaling, mitochondrial depolarization and neuronal cell death in cultured rat hippocampal neurons. Pretreatment with dapoxetine for 10min inhibited glutamate-induced intracellular free Ca(2+) concentration ([Ca(2+)]i) increases in a concentration-dependent manner (Half maximal inhibitory concentration= 4...
March 16, 2017: European Journal of Pharmacology
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