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bk channel pharmacology

Yanting Wang, Wenxian Lan, Zhenzhen Yan, Jing Gao, Xinlian Liu, Sheng Wang, Xiying Guo, Chunxi Wang, Hu Zhou, Jiuping Ding, Chunyang Cao
Large-conductance Ca2+ - and voltage-dependent K+ (BK) channels display diverse biological functions while their pore-forming α subunit is coded by a single Slo1 gene. The variety of BK channels is correlated with the effects of BKα coexpression with auxiliary β (β1-β4) subunits, as well as newly defined γ subunits. Charybdotoxin (ChTX) blocks BK channel through physically occluding the K+ -conduction pore. Human brain enriched β4 subunit (hβ4) alters the conductance-voltage curve, slows activation and deactivation time courses of BK channels...
March 15, 2018: Scientific Reports
Michael E Authement, Ludovic D Langlois, Ryan D Shepard, Caroline A Browne, Irwin Lucki, Haifa Kassis, Fereshteh S Nugent
Centrally released corticotropin-releasing factor or hormone (extrahypothalamic CRF or CRH) in the brain is involved in the behavioral and emotional responses to stress. The lateral habenula (LHb) is an epithalamic brain region involved in value-based decision-making and stress evasion. Through its inhibition of dopamine-mediated reward circuitry, the increased activity of the LHb is associated with addiction, depression, schizophrenia, and behavioral disorders. We found that extrahypothalamic CRF neurotransmission increased neuronal excitability in the LHb...
March 6, 2018: Science Signaling
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
Jun Huang, Li-Qun Ma, Yongle Yang, Nana Wen, Wan Zhou, Congli Cai, Qing-Hua Liu, Jinhua Shen
Artemisia annua L. belongs to the Asteraceae family, which is indigenous to China. It has valuable pharmacological properties, such as antimalarial, anti-inflammatory, and anticancer properties. However, whether it possesses antiasthma properties is unknown. In the current study, chloroform extract of Artemisia annua L. (CEAA) was prepared, and we found that CEAA completely eliminated acetylcholine (ACh) or high K+-elicited (80 mM) contractions of mouse tracheal rings (TRs). Patch-clamp technique and ion channel blockers were employed to explore the underlying mechanisms of the relaxant effect of CEAA...
2017: Evidence-based Complementary and Alternative Medicine: ECAM
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
Pedro Martín, Melisa Moncada, Guruprasad Kuntamallappanavar, Alex M Dopico, Verónica Milesi
Thiazide-like diuretics are the most commonly used drugs to treat arterial hypertension, with their efficacy being linked to their chronic vasodilatory effect. Previous studies suggest that activation of the large conductance voltage- and Ca2+ -dependent K+ (BK) channel (Slo 1, MaxiK channel) is responsible for the thiazide-induced vasodilatory effect. But the direct electrophysiological evidence supporting this claim is lacking. BK channels can be associated with one small accessory β-subunit (β1 -β4 ) that confers specific biophysical and pharmacological characteristics to the current phenotype...
November 30, 2017: Acta Pharmacologica Sinica
Luke E Whitmire, Ling Ling, Vladslav Bugay, Chase M Carver, Santosh Timilsina, Hui-Hsiu Chuang, David B Jaffe, Mark S Shapiro, Jose E Cavazos, Robert Brenner
A major challenge is to understand maladaptive changes in ion channels that sets neurons on a course towards epilepsy development. Voltage- and calcium-activated K+ (BK) channels contribute to early spike timing in neurons, and studies indicate that the BK channel plays a pathological role in increasing excitability early after a seizure. Here, we have investigated changes in BK channels and their accessory β4 subunit (KCNMB4) in dentate gyrus (DG) granule neurons of the hippocampus, key neurons that regulate excitability of the hippocampus circuit...
2017: PloS One
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
Ken Lee, Ayu Isogai, Minori Antoh, Shunichi Kajioka, Masatoshi Eto, Hikaru Hashitani
To explore the roles of various K+ channels in regulating the spontaneous activity of bladder muscularis mucosae (MM) that is considered to play an important role in maintaining mucosal function. Effects of K+ channel modulators on electrical and contractile activity in the guinea-pig bladder MM were examined using intracellular microelectrode and isometric tension recording. The MM predominately generated bursting spontaneous action potentials (SAPs) and phasic contractions (SPCs) that were blocked by nifedipine (1µM)...
January 5, 2018: European Journal of Pharmacology
Dimitrios Kadas, Aylin Klein, Niklas Krick, Jason W Worrell, Stefanie Ryglewski, Carsten Duch
Behaviorally adequate neuronal firing patterns are critically dependent on the specific types of ion channel expressed and on their subcellular localization. This study combines in situ electrophysiology with genetic and pharmacological intervention in larval Drosophila melanogaster of both sexes to address localization and function of L-type like calcium channels in motoneurons. We demonstrate that Dmca1D (Cav 1 homolog) L-type like calcium channels localize to both the somatodendritic and the axonal compartment of larval crawling motoneurons...
November 8, 2017: Journal of Neuroscience: the Official Journal of the Society for Neuroscience
Rachael Baylie, Majid Ahmed, Adrian D Bonev, David C Hill-Eubanks, Thomas J Heppner, Mark T Nelson, Adam S Greenstein
The aim of this study was to investigate mechanisms by which adiponectin influences vascular Ca2+ signaling, K+ channel activity and thus contractile tone of small arteries. Vasodilation to adiponectin was studied in mesenteric resistance arteries constricted with intraluminal pressure. Ca2+ signals were characterized using high speed confocal microscopy of intact arteries. Patch clamp investigated the effect of adiponectin on individual VSMC potassium (K+ ) channel currents. Adiponectin dilated arteries constricted with pressure-induced tone by approximately 5% and the induced vasodilation was only transient...
August 2017: Physiological Reports
Inge E Krabbendam, Birgit Honrath, Carsten Culmsee, Amalia M Dolga
Ca(2+)-activated K(+) channels (KCa) are expressed at the plasma membrane and in cellular organelles. Expression of all KCa channel subtypes (BK, IK and SK) has been detected at the inner mitochondrial membrane of several cell types. Primary functions of these mitochondrial KCa channels include the regulation of mitochondrial ROS production, maintenance of the mitochondrial membrane potential and preservation of mitochondrial calcium homeostasis. These channels are therefore thought to contribute to cellular protection against oxidative stress through mitochondrial mechanisms of preconditioning...
July 22, 2017: Cell Calcium
Xiang-Chong Wang, Wen-Tao Sun, Jie Fu, Jun-Hao Huang, Cheuk-Man Yu, Malcolm John Underwood, Guo-Wei He, Qin Yang
Despite increasing knowledge of the significance of calcium-activated potassium (KCa) and canonical transient receptor potential (TRPC) channels in endothelial physiology, no studies so far have investigated the link between these two distinct types of channels in the control of vascular tone in pathological conditions. We previously demonstrated that hypoxia-reoxygenation (H-R) inhibits endothelial KCa and TRPC3 channels in porcine coronary arteries (PCAs). The present study further investigated whether modulation of TRPC3 is involved in H-R-induced KCa channel inhibition and associated vasodilatory dysfunction using approaches of wire myography, whole-cell voltage-clamp, and coimmunoprecipitation...
July 19, 2017: Scientific Reports
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
Charles Owen Smith, Keith Nehrke, Paul S Brookes
Mitochondria play an important role in tissue ischemia and reperfusion (IR) injury, with energetic failure and the opening of the mitochondrial permeability transition pore being the major causes of IR-induced cell death. Thus, mitochondria are an appropriate focus for strategies to protect against IR injury. Two widely studied paradigms of IR protection, particularly in the field of cardiac IR, are ischemic preconditioning (IPC) and volatile anesthetic preconditioning (APC). While the molecular mechanisms recruited by these protective paradigms are not fully elucidated, a commonality is the involvement of mitochondrial K(+) channel opening...
June 9, 2017: Biochemical Journal
Wuyang Wang, Xiaoli Zhang, Qiong Gao, Maria Lawas, Lu Yu, Xiping Cheng, Mingxue Gu, Nirakar Sahoo, Xinran Li, Ping Li, Stephen Ireland, Andrea Meredith, Haoxing Xu
The resting membrane potential (Δψ) of the cell is negative on the cytosolic side and determined primarily by the plasma membrane's selective permeability to K+ We show that lysosomal Δψ is set by lysosomal membrane permeabilities to Na+ and H+ , but not K+ , and is positive on the cytosolic side. An increase in juxta-lysosomal Ca2+ rapidly reversed lysosomal Δψ by activating a large voltage-dependent and K+ -selective conductance (LysoKVCa ). LysoKVCa is encoded molecularly by SLO1 proteins known for forming plasma membrane BK channels...
June 5, 2017: Journal of Cell Biology
Fatima Maqoud, Michela Cetrone, Antonietta Mele, Domenico Tricarico
The large-conductance Ca(2+)-activated K(+) (BK) channel is broadly expressed in various mammalian cells and tissues such as neurons, skeletal muscles (sarco-BK), and smooth muscles. These channels are activated by changes in membrane electrical potential and by increases in the concentration of intracellular calcium ion (Ca(2+)). The large-conductance Ca(2+)-activated K(+) (BK) channel is subjected to many mechanisms that add diversity to the BK channel α subunit gene. These channels are indeed subject to alternative splicing, auxiliary subunits modulation, post-translational modifications and protein-protein interactions...
April 28, 2017: Physiological Genomics
Jean-Claude Henquin, Denis Dufrane, Valery Gmyr, Julie Kerr-Conte, Myriam Nenquin
AIMS: To understand better the control of insulin secretion by human β cells and to identify similarities to and differences from rodent models. METHODS: Dynamic insulin secretion was measured in perifused human islets treated with pharmacological agents of known modes of action. RESULTS: Glucokinase activation (Ro28-1675) lowered the glucose threshold for stimulation of insulin secretion to 1 mmol/L (G1), augmented the response to G3-G5 but not to G8-G15, whereas tolbutamide remained active in G20, which indicates that not all KATP channels were closed by high glucose concentrations...
January 24, 2017: Diabetes, Obesity & Metabolism
Flavia Carla Meotti, Cláudia Pinto Figueiredo, Marianne Manjavachi, João B Calixto
The kinin receptor B1 and the transient receptor potential ankyrin 1 (TRPA1) work as initiators and gatekeepers of nociception and inflammation. This study reports that the nociceptive transmission induced by activation of B1 receptor is dependent on TRPA1 ion channel. The mechanical hyperalgesia was induced by intrathecal (i.t.) injection of B1 agonist des-Arginine(9)-bradykinin (DABK) or TRPA1 agonist cinnamaldehyde and was evaluated by the withdrawal response after von Frey Hair application in the hind paw...
February 1, 2017: Biochemical Pharmacology
Ramon Latorre, Karen Castillo, Willy Carrasquel-Ursulaez, Romina V Sepulveda, Fernando Gonzalez-Nilo, Carlos Gonzalez, Osvaldo Alvarez
Large-conductance Ca2+- and voltage-activated K+ (BK) channels play many physiological roles ranging from the maintenance of smooth muscle tone to hearing and neurosecretion. BK channels are tetramers in which the pore-forming α subunit is coded by a single gene (Slowpoke, KCNMA1). In this review, we first highlight the physiological importance of this ubiquitous channel, emphasizing the role that BK channels play in different channelopathies. We next discuss the modular nature of BK channel-forming protein, in which the different modules (the voltage sensor and the Ca2+ binding sites) communicate with the pore gates allosterically...
January 2017: Physiological Reviews
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