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bk channel inhibitor

Ursula Castro de Oliveira, Milton Yutaka Nishiyama, Maria Beatriz Viana Dos Santos, Andria de Paula Santos-da-Silva, Hipócrates de Menezes Chalkidis, Andreia Souza-Imberg, Denise Maria Candido, Norma Yamanouye, Valquíria Abrão Coronado Dorce, Inácio de Loiola Meirelles Junqueira-de-Azevedo
BACKGROUND: Except for the northern region, where the Amazonian black scorpion, T. obscurus, represents the predominant and most medically relevant scorpion species, Tityus serrulatus, the Brazilian yellow scorpion, is widely distributed throughout Brazil, causing most envenoming and fatalities due to scorpion sting. In order to evaluate and compare the diversity of venom components of Tityus obscurus and T. serrulatus, we performed a transcriptomic investigation of the telsons (venom glands) corroborated by a shotgun proteomic analysis of the venom from the two species...
2018: PloS One
Tanziyah Muqeem, Biswarup Ghosh, Vitor Pinto, Angelo C Lepore, Manuel Covarrubias
Presynaptic voltage-gated K+ (Kv) channels in dorsal root ganglion (DRG) neurons are thought to regulate nociceptive synaptic transmission in the spinal dorsal horn. However, the Kv channel subtypes responsible for this critical role have not been identified. The Kv3.4 channel is particularly important because it is robustly expressed in DRG nociceptors, where it regulates action potential (AP) duration. Furthermore, Kv3.4 dysfunction is implicated in the pathophysiology of neuropathic pain in multiple pain models...
March 14, 2018: Journal of Neuroscience: the Official Journal of the Society for Neuroscience
Katsuhito Matsuki, Daiki Kato, Masashi Takemoto, Yoshiaki Suzuki, Hisao Yamamura, Susumu Ohya, Hiroshi Takeshima, Yuji Imaizumi
Physiological functions of type 3 ryanodine receptors (RyR3) in smooth muscle (SM) tissues are not well understood, in spite of their wide expression. However, the short isoform of RyR3 is known to be a dominant negative variant (DN-RyR3), which may negatively regulate functions of both RyR2 and full length (FL)-RyR3 by forming hetero-tetramers. Here, functional roles of RyR3 in the regulation of Ca2+ signaling in mesenteric artery SM cells (MASMCs) were examined using RyR3 homozygous knockout mice (RyR3-/- )...
March 14, 2018: American Journal of Physiology. Cell Physiology
F Xin, H Huang, P Liu, J Ren, S Zhang, Y Cheng, W Wang
BACKGROUND: Muscarinic acetylcholine receptor (mAChR) activation is an important factor to enhance the motility of gastrointestinal (GI) smooth muscle. Large conductance Ca2+ -activated potassium (BK) channels are widely expressed in GI smooth muscle. Roles of BK in carbachol (a mAChR agonist) induced enhancement of GI motility and the molecular mechanisms remains unknown and were investigated in this study. METHODS: Colonic smooth muscle (CSM) strip was perfused to record motility in vitro...
February 28, 2018: Neurogastroenterology and Motility: the Official Journal of the European Gastrointestinal Motility Society
Ming Lu, Jian-Ri Li, Lery Alvarez-Lugo, Yan Li, Shan Yu, Xuanhao Li, Benkang Shi, Toby C Chai
Bladder urothelium plays an active role in response to bacterial infection. There is little known about the electrophysiological activity in urothelial cells in this process. We used a non-enzymatic method to isolate bladder urothelial tissue and to patch clamp umbrella cells in situ. A 200pS conductance potassium (K+ ) channel was detected from female C57BL6 mice. Of 58 total patches, 17.2% patches displayed the 200pS K+ conductance channel. This K+ conductance channel showed Ca2+ sensitivity and voltage dependence...
February 21, 2018: American Journal of Physiology. Cell Physiology
Sandra Frankenreiter, Dieter Groneberg, Anna Kuret, Thomas Krieg, Peter Ruth, Andreas Friebe, Robert Lukowski
Aims: It has been suggested that the nitric oxide-sensitive guanylyl cyclase (NO-GC)/cGMP-dependent signaling pathway affords protection against cardiac damage during acute myocardial infarction (AMI). It is, however, not clear whether the NO-GC/cGMP system confers its favorable effects through a mechanism located in cardiomyocytes (CMs). The aim of this study was to evaluate the infarct-limiting effects of the endogenous NO-GC in CMs in vivo. Methods and Results: Ischemia/reperfusion (I/R) injury was evaluated in mice with a cardiomyocyte-specific deletion of NO-GC (CM NO-GC KO) and in control siblings (CM NO-GC CTR) subjected to an in vivo model of AMI...
February 9, 2018: Cardiovascular Research
Jay S Naik, Benjimen R Walker
Following chronic hypoxia (CH), the systemic vasculature exhibits blunted vasoconstriction due to endothelial-dependent hyperpolarization (EDH). Previous data demonstrate that subsequent to CH, EDH-mediated vasodilation switches from a reliance on SKca and IKca channels to activation of the endothelial BKca channels (eBK). The mechanism by which endothelial cell stimulation activates eBK channels following CH is not known. We hypothesized that following CH, EDH-dependent vasodilation involves a TRPV4-dependent activation of eBK channels...
January 29, 2018: Pflügers Archiv: European Journal of Physiology
Bartłomiej Augustynek, Piotr Koprowski, Daria Rotko, Wolfram S Kunz, Adam Szewczyk, Bogusz Kulawiak
Potassium channel openers (KCOs) have been shown to play a role in cytoprotection through the activation of mitochondrial potassium channels. Recently, in several reports, a number of data has been described as off-target actions for KCOs. In the present study, we investigated the effects of BKCa channel openers CGS7181, CGS7184, NS1619, and NS004 in neuronal cells. For the purpose of this research, we used a rat brain, the mouse hippocampal HT22 cells, and the human astrocytoma U-87 MG cell line. We showed that CGS7184 activated the mitochondrial BKCa (mitoBKCa) channel in single-channel recordings performed on astrocytoma mitoplasts...
January 25, 2018: International Journal of Molecular Sciences
Jiaju Wang, Donghee Kim
Large-conductance KCa (BK) and other voltage-dependent K(+) channels (Kv) are highly expressed in carotid body (CB) glomus cells, but their role in hypoxia-induced excitation is still not well defined and remains controversial. We addressed this issue by studying the effects of inhibitors of BK (IBTX) and BK/Kv (TEA/4-AP) on [Ca(2+) ]i responses to a wide range of hypoxia at different levels of resting cell Em. IBTX and TEA/4-AP did not affect the basal [Ca(2+) ]i in isolated glomus cells bathed in 5 mm KClo , but elicited transient increases in [Ca(2+) ]i in cells that were moderately depolarized (11-20 mV) by elevation of [KCl]o (12-20 mm)...
November 21, 2017: Journal of Physiology
Sandra Frankenreiter, Piotr Bednarczyk, Angelina Kniess, Nadja Bork, Julia Straubinger, Piotr Koprowski, Antoni Wrzosek, Eva Mohr, Angela Logan, Michael P Murphy, Meinrad Gawaz, Thomas Krieg, Adam Szewczyk, Viacheslav O Nikolaev, Peter Ruth, Robert Lukowski
Background -The nitric oxide-sensitive guanylyl cyclase (NO-GC)/cyclic guanosine-3',5'-monophosphate (cGMP)/cGMP-dependent protein kinase type I (cGKI)-signaling pathway can afford protection against the ischemia and reperfusion (I/R) injury that occurs during myocardial infarction (MI). Reportedly, voltage and Ca(2+)-activated K(+) channels of the BK-type are stimulated by cGMP/cGKI and recent ex-vivo studies implicated that increased BK activity favors the survival of the myocardium at I/R. It remains unclear, however, whether the molecular events downstream of cGMP involve BK channels present in cardiomyocytes (CMs) or in other cardiac cell types...
October 19, 2017: Circulation
Kiril L Hristov, Shankar P Parajuli, Aaron Provence, Eric S Rovner, Georgi V Petkov
Estrogens have an important role in regulating detrusor smooth muscle (DSM) function. However, the underlying molecular and cellular mechanisms by which estrogens control human DSM excitability and contractility are not well known. Here, we used human DSM specimens from open bladder surgeries on 27 patients to elucidate the mechanism by which 17β-estradiol regulates large conductance voltage- and Ca(2+)-activated K(+) (BK) channels, the most prominent K(+) channels in human DSM We employed single BK channel recordings on inside-out excised membrane patches, perforated whole-cell patch-clamp on freshly isolated DSM cells, and isometric tension recordings on DSM-isolated strips to investigate the mechanism by which 17β-estradiol activates BK channels...
July 2017: Physiological Reports
Biqiong Zhang, Yaodong Zhang, Wenning Wu, Tanzhen Xu, Yanyan Yin, Junyan Zhang, Dake Huang, Weizu Li
BACKGROUND: Neuroinflammation mediated by NLRP1 (nucleotide-binding oligomerization domain (NOD)-like receptor protein 1) inflammasome plays an important role in many neurological diseases such as Parkinson's disease (PD) and Alzheimer's disease (AD). Our previous studies showed that chronic glucocorticoid (GC) exposure increased brain inflammation via NLRP1 inflammasome and induce neurodegeneration. However, little is known about the mechanism of chronic GC exposure on NLRP1 inflammasome activation in hippocampal neurons...
July 21, 2017: Journal of Neuroinflammation
Thomas M Leurgans, Maria Bloksgaard, Akhmadjon Irmukhamedov, Lars P Riber, Jo G R De Mey
In human pericardial resistance arteries, effects of the endothelium-dependent vasodilator bradykinin are mediated by NO during contraction induced by K(+) or the TxA2 analogue U46619 and by H2 O2 during contraction by endothelin-1 (ET-1), respectively. We tested the hypotheses that ET-1 reduces relaxing effects of NO and increases those of H2 O2 in resistance artery smooth muscle of patients with cardiovascular disease. Arterial segments, dissected from the parietal pericardium of 39 cardiothoracic surgery patients, were studied by myography during amplitude-matched contractions induced by K(+) , the TXA2 analogue U46619 or ET-1...
July 7, 2017: Basic & Clinical Pharmacology & Toxicology
Jin Bo Su
NO produced by eNOS plays important roles in the cardiovascular system. Alterations in eNOS activity and expression occur in various cardiovascular disorders and eNOS constitutes a therapeutic target. In addition to posttranslational modifications of eNOS that affect eNOS activity, transcriptional and post-transcriptional regulation of eNOS expression also controlls eNOS-derived NO production. Bradykinin is an important determinant of vascular function and participates in the regulation of eNOS activity and expression...
June 22, 2017: Current Pharmaceutical Design
Richard B Thorpe, Margaret C Hubbell, Jinjutha Silpanisong, James M Williams, William J Pearce
Long-term hypoxia (LTH) attenuates nitric oxide-induced vasorelaxation in ovine middle cerebral arteries. Because cGMP-dependent protein kinase (PKG) is an important mediator of NO signaling in vascular smooth muscle, we tested the hypothesis that LTH diminishes the ability of PKG to interact with target proteins and cause vasorelaxation. Prominent among proteins that regulate vascular tone is the large-conductance Ca(2+)-sensitive K(+) (BK) channel, which is a substrate for PKG and is responsive to phosphorylation on multiple serine/threonine residues...
July 1, 2017: American Journal of Physiology. Heart and Circulatory Physiology
Nathan A Zaidman, Angela Panoskaltsis-Mortari, Scott M O'Grady
KEY POINTS: Hydrocortisone (HC) is required for activation of large-conductance Ca(2+) -activated K(+) current (BK) by purinergic receptor agonists. HC reduces insertion of the stress-regulated exon (STREX) in the KCNMA1 gene, permitting protein kinase C (PKC)-dependent channel activation. Overlapping and unique purinergic signalling regions exist at the apical border of differentiated surface cells. BK channels localize in the cilia of surface cells. ABSTRACT: In the present study we investigated the role of hydrocortisone (HC) on uridine-5'-triphosphate (UTP)-stimulated ion transport in differentiated, pseudostratified epithelia derived from normal human bronchial basal cells...
July 15, 2017: Journal of Physiology
Yan Wang, Hai-Ying Sun, Ying-Guang Liu, Zheng Song, Gang She, Guo-Sheng Xiao, Yan Wang, Gui-Rong Li, Xiu-Ling Deng
The present study was designed to investigate whether large conductance Ca(2+) -activated K(+) (BK) channels were regulated by epidermal growth factor (EGF) receptor (EGFR) tyrosine kinase. BK current and channel tyrosine phosphorylation level were measured in BK-HEK 293 cells expressing both functional α-subunits and the auxiliary β1-subunits using electrophysiology, immunoprecipitation and Western blotting approaches, respectively, and the function of rat cerebral basilar arteries was determined with a wire myography system...
September 2017: Journal of Cellular and Molecular Medicine
Lama Al-Qusairi, Denis Basquin, Ankita Roy, Renuga Devi Rajaram, Marc P Maillard, Arohan R Subramanya, Olivier Staub
Adaptation of the organism to potassium (K+) deficiency requires precise coordination among organs involved in K+ homeostasis, including muscle, liver, and kidney. How the latter performs functional and molecular changes to ensure K+ retention is not well understood. Here, we investigated the role of ubiquitin-protein ligase NEDD4-2, which negatively regulates the epithelial sodium channel (ENaC), Na+/Cl- cotransporter (NCC), and with no-lysine-kinase 1 (WNK1). After dietary K+ restriction for 2 weeks, compared with control littermates, inducible renal tubular NEDD4-2 knockout (Nedd4LPax8/LC1 ) mice exhibited severe hypokalemia and urinary K+ wasting...
August 2017: Journal of the American Society of Nephrology: JASN
Robson Costa, Maíra A Bicca, Marianne N Manjavachi, Gabriela C Segat, Fabiana Chaves Dias, Elizabeth S Fernandes, João B Calixto
Kinin B1 (B1R) and B2 receptors (B2R) and the transient receptor potential vanilloid 4 (TRPV4) channel are known to play a critical role in the peripheral neuropathy induced by paclitaxel (PTX) in rodents. However, the downstream pathways activated by kinin receptors as well as the sensitizers of the TRPV4 channel involved in this process remain unknown. Herein, we investigated whether kinins sensitize TRPV4 channels in order to maintain PTX-induced peripheral neuropathy in mice. The mechanical hyperalgesia induced by bradykinin (BK, a B2R agonist) or des-Arg(9)-BK (DABK, a B1R agonist) was inhibited by the selective TRPV4 antagonist HC-067047...
March 10, 2017: Molecular Neurobiology
Yue Li, Hongxiang Hu, Jin-Bin Tian, Michael X Zhu, Roger G O'Neil
The large-conductance Ca(2+)-activated K(+) channel, BK (KCNMA1), is expressed along the connecting tubule (CNT) and cortical collecting duct (CCD) where it underlies flow- and Ca(2+)-dependent K(+) secretion. Its activity is partially under the control of the mechanosensitive transient receptor potential vanilloid type 4 (TRPV4) Ca(2+)-permeable channel. Recently, we identified three small-/intermediate-conductance Ca(2+)-activated K(+) channels, SK1 (KCNN1), SK3 (KCNN3), and IK1 (KCNN4), with notably high Ca(2+)-binding affinities, that are expressed in CNT/CCD and may be regulated by TRPV4-mediated Ca(2+) influx...
June 1, 2017: American Journal of Physiology. Renal Physiology
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