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Patton BL, Zhu P, ElSheikh A, Driggers CM, Shyng SL. Dynamic duo: Kir6 and SUR in K ATP channel structure and function. Channels (Austin) 2024; 18:2327708. [PMID: 38489043 PMCID: PMC10950283 DOI: 10.1080/19336950.2024.2327708] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2023] [Accepted: 01/14/2024] [Indexed: 03/17/2024] Open
Abstract
KATP channels are ligand-gated potassium channels that couple cellular energetics with membrane potential to regulate cell activity. Each channel is an eight subunit complex comprising four central pore-forming Kir6 inward rectifier potassium channel subunits surrounded by four regulatory subunits known as the sulfonylurea receptor, SUR, which confer homeostatic metabolic control of KATP gating. SUR is an ATP binding cassette (ABC) protein family homolog that lacks membrane transport activity but is essential for KATP expression and function. For more than four decades, understanding the structure-function relationship of Kir6 and SUR has remained a central objective of clinical significance. Here, we review progress in correlating the wealth of functional data in the literature with recent KATP cryoEM structures.
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Affiliation(s)
- Bruce L. Patton
- Department of Chemical Physiology and Biochemistry, School of Medicine, Oregon Health and Science University, Portland, OR, USA
| | - Phillip Zhu
- Department of Chemical Physiology and Biochemistry, School of Medicine, Oregon Health and Science University, Portland, OR, USA
| | - Assmaa ElSheikh
- Department of Chemical Physiology and Biochemistry, School of Medicine, Oregon Health and Science University, Portland, OR, USA
- Department of Medical Biochemistry, Tanta University, Tanta, Egypt
| | - Camden M. Driggers
- Department of Chemical Physiology and Biochemistry, School of Medicine, Oregon Health and Science University, Portland, OR, USA
| | - Show-Ling Shyng
- Department of Chemical Physiology and Biochemistry, School of Medicine, Oregon Health and Science University, Portland, OR, USA
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2
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Longden TA, Lederer WJ. Electro-metabolic signaling. J Gen Physiol 2024; 156:e202313451. [PMID: 38197953 PMCID: PMC10783436 DOI: 10.1085/jgp.202313451] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2023] [Revised: 10/27/2023] [Accepted: 12/14/2023] [Indexed: 01/11/2024] Open
Abstract
Precise matching of energy substrate delivery to local metabolic needs is essential for the health and function of all tissues. Here, we outline a mechanistic framework for understanding this critical process, which we refer to as electro-metabolic signaling (EMS). All tissues exhibit changes in metabolism over varying spatiotemporal scales and have widely varying energetic needs and reserves. We propose that across tissues, common signatures of elevated metabolism or increases in energy substrate usage that exceed key local thresholds rapidly engage mechanisms that generate hyperpolarizing electrical signals in capillaries that then relax contractile elements throughout the vasculature to quickly adjust blood flow to meet changing needs. The attendant increase in energy substrate delivery serves to meet local metabolic requirements and thus avoids a mismatch in supply and demand and prevents metabolic stress. We discuss in detail key examples of EMS that our laboratories have discovered in the brain and the heart, and we outline potential further EMS mechanisms operating in tissues such as skeletal muscle, pancreas, and kidney. We suggest that the energy imbalance evoked by EMS uncoupling may be central to cellular dysfunction from which the hallmarks of aging and metabolic diseases emerge and may lead to generalized organ failure states-such as diverse flavors of heart failure and dementia. Understanding and manipulating EMS may be key to preventing or reversing these dysfunctions.
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Affiliation(s)
- Thomas A. Longden
- Department of Physiology, University of Maryland School of Medicine, Baltimore, MD, USA
- Laboratory of Neurovascular Interactions, Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, MD, USA
| | - W. Jonathan Lederer
- Department of Physiology, University of Maryland School of Medicine, Baltimore, MD, USA
- Laboratory of Molecular Cardiology, Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, MD, USA
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3
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ElSheikh A, Driggers CM, Shyng SL. Non-radioactive Rb + Efflux Assay for Screening K ATP Channel Modulators. Methods Mol Biol 2024; 2796:191-210. [PMID: 38856903 DOI: 10.1007/978-1-0716-3818-7_12] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/11/2024]
Abstract
ATP-sensitive potassium (KATP) channels function as metabolic sensors that link cell membrane excitability to the cellular energy status by controlling potassium ion (K+) flow across the cell membrane according to intracellular ATP and ADP concentrations. As such, KATP channels influence a broad spectrum of physiological processes, including insulin secretion and cardiovascular functions. KATP channels are hetero-octamers, consisting of four inward rectifier potassium channel subunits, Kir6.1 or Kir6.2, and four sulfonylurea receptors (SURs), SUR1, SUR2A, or SUR2B. Different Kir6 and SUR isoforms assemble into KATP channel subtypes with distinct tissue distributions and physiological functions. Mutations in the genes encoding KATP channel subunits underlie various human diseases. Targeted treatment for these diseases requires subtype-specific KATP channel modulators. Rubidium ions (Rb+) also pass through KATP channels, and Rb+ efflux assays can be used to assess KATP channel function and activity. Flame atomic absorption spectroscopy (Flame-AAS) combined with microsampling can measure Rb+ in small volume, which provides an efficient tool to screen for compounds that alter KATP channel activity in Rb+ efflux assays. In this chapter, we describe a detailed protocol for Rb+ efflux assays designed to identify new KATP channel modulators with potential therapeutic utilities.
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Affiliation(s)
- Assmaa ElSheikh
- Department of Chemical Physiology and Biochemistry, School of Medicine, Oregon Health and Science University, Portland, OR, USA.
- Department of Medical Biochemistry, Tanta University, Tanta, Egypt.
| | - Camden M Driggers
- Department of Chemical Physiology and Biochemistry, School of Medicine, Oregon Health and Science University, Portland, OR, USA
| | - Show-Ling Shyng
- Department of Chemical Physiology and Biochemistry, School of Medicine, Oregon Health and Science University, Portland, OR, USA
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Mollace R, Scarano F, Bava I, Carresi C, Maiuolo J, Tavernese A, Gliozzi M, Musolino V, Muscoli S, Palma E, Muscoli C, Salvemini D, Federici M, Macrì R, Mollace V. Modulation of the nitric oxide/cGMP pathway in cardiac contraction and relaxation: Potential role in heart failure treatment. Pharmacol Res 2023; 196:106931. [PMID: 37722519 DOI: 10.1016/j.phrs.2023.106931] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/31/2023] [Revised: 09/09/2023] [Accepted: 09/15/2023] [Indexed: 09/20/2023]
Abstract
Evidence exists that heart failure (HF) has an overall impact of 1-2 % in the global population being often associated with comorbidities that contribute to increased disease prevalence, hospitalization, and mortality. Recent advances in pharmacological approaches have significantly improved clinical outcomes for patients with vascular injury and HF. Nevertheless, there remains an unmet need to clarify the crucial role of nitric oxide/cyclic guanosine 3',5'-monophosphate (NO/cGMP) signalling in cardiac contraction and relaxation, to better identify the key mechanisms involved in the pathophysiology of myocardial dysfunction both with reduced (HFrEF) as well as preserved ejection fraction (HFpEF). Indeed, NO signalling plays a crucial role in cardiovascular homeostasis and its dysregulation induces a significant increase in oxidative and nitrosative stress, producing anatomical and physiological cardiac alterations that can lead to heart failure. The present review aims to examine the molecular mechanisms involved in the bioavailability of NO and its modulation of downstream pathways. In particular, we focus on the main therapeutic targets and emphasize the recent evidence of preclinical and clinical studies, describing the different emerging therapeutic strategies developed to counteract NO impaired signalling and cardiovascular disease (CVD) development.
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Affiliation(s)
- Rocco Mollace
- Pharmacology Laboratory, Institute of Research for Food Safety and Health IRC-FSH, Department of Health Sciences, University Magna Graecia of Catanzaro, Catanzaro 88100, Italy; Department of Systems Medicine, University of Rome Tor Vergata, Italy
| | - Federica Scarano
- Pharmacology Laboratory, Institute of Research for Food Safety and Health IRC-FSH, Department of Health Sciences, University Magna Graecia of Catanzaro, Catanzaro 88100, Italy
| | - Irene Bava
- Pharmacology Laboratory, Institute of Research for Food Safety and Health IRC-FSH, Department of Health Sciences, University Magna Graecia of Catanzaro, Catanzaro 88100, Italy
| | - Cristina Carresi
- Veterinary Pharmacology Laboratory, Institute of Research for Food Safety and Health IRC-FSH, Department of Health Sciences, University Magna Graecia of Catanzaro, Catanzaro 88100, Italy
| | - Jessica Maiuolo
- Pharmaceutical Biology Laboratory, Institute of Research for Food Safety and Health IRC-FSH, Department of Health Sciences, University Magna Graecia of Catanzaro, Catanzaro 88100, Italy
| | - Annamaria Tavernese
- Pharmacology Laboratory, Institute of Research for Food Safety and Health IRC-FSH, Department of Health Sciences, University Magna Graecia of Catanzaro, Catanzaro 88100, Italy
| | - Micaela Gliozzi
- Pharmacology Laboratory, Institute of Research for Food Safety and Health IRC-FSH, Department of Health Sciences, University Magna Graecia of Catanzaro, Catanzaro 88100, Italy
| | - Vincenzo Musolino
- Pharmaceutical Biology Laboratory, Institute of Research for Food Safety and Health IRC-FSH, Department of Health Sciences, University Magna Graecia of Catanzaro, Catanzaro 88100, Italy
| | - Saverio Muscoli
- Division of Cardiology, Foundation PTV Polyclinic Tor Vergata, Rome 00133, Italy
| | - Ernesto Palma
- Veterinary Pharmacology Laboratory, Institute of Research for Food Safety and Health IRC-FSH, Department of Health Sciences, University Magna Graecia of Catanzaro, Catanzaro 88100, Italy
| | - Carolina Muscoli
- Pharmacology Laboratory, Institute of Research for Food Safety and Health IRC-FSH, Department of Health Sciences, University Magna Graecia of Catanzaro, Catanzaro 88100, Italy
| | - Daniela Salvemini
- Department of Pharmacology and Physiology, Saint Louis University School of Medicine, St. Louis, MO 63104, USA
| | - Massimo Federici
- Department of Systems Medicine, University of Rome Tor Vergata, Italy
| | - Roberta Macrì
- Pharmacology Laboratory, Institute of Research for Food Safety and Health IRC-FSH, Department of Health Sciences, University Magna Graecia of Catanzaro, Catanzaro 88100, Italy.
| | - Vincenzo Mollace
- Pharmacology Laboratory, Institute of Research for Food Safety and Health IRC-FSH, Department of Health Sciences, University Magna Graecia of Catanzaro, Catanzaro 88100, Italy; Renato Dulbecco Institute, Lamezia Terme, Catanzaro 88046, Italy.
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Driggers CM, Shyng SL. Mechanistic insights on KATP channel regulation from cryo-EM structures. J Gen Physiol 2022; 155:213723. [PMID: 36441147 PMCID: PMC9700523 DOI: 10.1085/jgp.202113046] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2022] [Revised: 10/19/2022] [Accepted: 11/08/2022] [Indexed: 11/29/2022] Open
Abstract
Gated by intracellular ATP and ADP, ATP-sensitive potassium (KATP) channels couple cell energetics with membrane excitability in many cell types, enabling them to control a wide range of physiological processes based on metabolic demands. The KATP channel is a complex of four potassium channel subunits from the Kir channel family, Kir6.1 or Kir6.2, and four sulfonylurea receptor subunits, SUR1, SUR2A, or SUR2B, from the ATP-binding cassette (ABC) transporter family. Dysfunction of KATP channels underlies several human diseases. The importance of these channels in human health and disease has made them attractive drug targets. How the channel subunits interact with one another and how the ligands interact with the channel to regulate channel activity have been long-standing questions in the field. In the past 5 yr, a steady stream of high-resolution KATP channel structures has been published using single-particle cryo-electron microscopy (cryo-EM). Here, we review the advances these structures bring to our understanding of channel regulation by physiological and pharmacological ligands.
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Affiliation(s)
- Camden M. Driggers
- Department of Chemical Physiology and Biochemistry, School of Medicine, Oregon Health and Science University, Portland, OR
| | - Show-Ling Shyng
- Department of Chemical Physiology and Biochemistry, School of Medicine, Oregon Health and Science University, Portland, OR,Correspondence to Show-Ling Shyng:
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Vascular K ATP channel structural dynamics reveal regulatory mechanism by Mg-nucleotides. Proc Natl Acad Sci U S A 2021; 118:2109441118. [PMID: 34711681 PMCID: PMC8694068 DOI: 10.1073/pnas.2109441118] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/30/2021] [Indexed: 11/24/2022] Open
Abstract
Vascular KATP channels formed by the potassium channel Kir6.1 and its regulatory protein SUR2B maintain blood pressure in the physiological range. Overactivity of the channel due to genetic mutations in either Kir6.1 or SUR2B causes severe cardiovascular pathologies known as Cantú syndrome. The cryogenic electron microscopy structures of the vascular KATP channel reported here show multiple, dynamically related conformations of the regulatory subunit SUR2B. Molecular dynamics simulations reveal the negatively charged ED-domain in SUR2B, a stretch of 15 glutamate (E) and aspartate (D) residues not previously resolved, play a key MgADP-dependent role in mediating interactions at the interface between the SUR2B and Kir6.1 subunits. Our findings provide a mechanistic understanding of how channel activity is regulated by intracellular MgADP. Vascular tone is dependent on smooth muscle KATP channels comprising pore-forming Kir6.1 and regulatory SUR2B subunits, in which mutations cause Cantú syndrome. Unique among KATP isoforms, they lack spontaneous activity and require Mg-nucleotides for activation. Structural mechanisms underlying these properties are unknown. Here, we determined cryogenic electron microscopy structures of vascular KATP channels bound to inhibitory ATP and glibenclamide, which differ informatively from similarly determined pancreatic KATP channel isoform (Kir6.2/SUR1). Unlike SUR1, SUR2B subunits adopt distinct rotational “propeller” and “quatrefoil” geometries surrounding their Kir6.1 core. The glutamate/aspartate-rich linker connecting the two halves of the SUR-ABC core is observed in a quatrefoil-like conformation. Molecular dynamics simulations reveal MgADP-dependent dynamic tripartite interactions between this linker, SUR2B, and Kir6.1. The structures captured implicate a progression of intermediate states between MgADP-free inactivated, and MgADP-bound activated conformations wherein the glutamate/aspartate-rich linker participates as mobile autoinhibitory domain, suggesting a conformational pathway toward KATP channel activation.
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Ding L, Jia C, Zhang Y, Wang W, Zhu W, Chen Y, Zhang T. Baicalin relaxes vascular smooth muscle and lowers blood pressure in spontaneously hypertensive rats. Biomed Pharmacother 2018; 111:325-330. [PMID: 30590320 DOI: 10.1016/j.biopha.2018.12.086] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2018] [Revised: 12/12/2018] [Accepted: 12/19/2018] [Indexed: 12/24/2022] Open
Abstract
Scutellaria baicalensis Georgi is an extensively used medicinal herb for the treatment of hypertension in traditional Chinese medicine. Baicalin is the most abundant flavone compound present in Scutellaria baicalensis Georgi and endothelium-dependent vascular activities of baicalin have been suggested. However, the pharmacological implications and mechanisms of baicalin under hypertensive conditions remain to be investigated. The current study examined the blood pressure-lowering effect of baicalin in a spontaneously hypertensive rat (SHR) model. Moreover, vascular activities and mechanisms of baicalin were investigated under hypertensive conditions. The results demonstrate that baicalin treatment lowers the blood pressure in SHRs in vivo. Ex vivo vascular reactivity assay reveals that baicalin relaxes phenylephrine (PE)-constricted SHR aortas in an endothelium-independent manner. Baicalin attenuates Angiotensin II (Ang II) or potassium chloride (KCl)-induced vasoconstriction in SHR aortas as well. Baicalin also relaxes SHR aortas in the presence of different Ca2+ channel blockers such as nifedipine and SKF96365 in response to PE-induced constriction. Most importantly, ATP-sensitive potassium channel (KATP) blockade partially abrogated the vasorelaxant effect of baicalin. In summary, the current study demonstrates for the first time that intracellular Ca2+ regulation in vascular smooth muscle is mechanistically implicated in the vasorelaxant effect of baicalin under hypertensive conditions. Furthermore, activated KATP channels are in part required for the vasorelaxant effect of baicalin under hypertensive conditions. Thus, the work here sheds novel pharmacological and mechanistic insights into the blood pressure-lowering effect of baicalin, which may help better understand the therapeutic application of Scutellaria baicalensis Georgi in the treatment of hypertension.
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Affiliation(s)
- Liliqiang Ding
- Yueyang Hospital, Shanghai University of Traditional Chinese Medicine, Shanghai, China; Clinical Research Institute of Integrative Medicine, Shanghai Academy of Traditional Chinese Medicine, Shanghai, China
| | - Chenglin Jia
- Yueyang Hospital, Shanghai University of Traditional Chinese Medicine, Shanghai, China
| | - Yong Zhang
- Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, China
| | - Wenjian Wang
- Clinical Research Institute of Integrative Medicine, Shanghai Academy of Traditional Chinese Medicine, Shanghai, China
| | - Weiliang Zhu
- Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, China
| | - Yu Chen
- Yueyang Hospital, Shanghai University of Traditional Chinese Medicine, Shanghai, China; Clinical Research Institute of Integrative Medicine, Shanghai Academy of Traditional Chinese Medicine, Shanghai, China.
| | - Teng Zhang
- Yueyang Hospital, Shanghai University of Traditional Chinese Medicine, Shanghai, China; Clinical Research Institute of Integrative Medicine, Shanghai Academy of Traditional Chinese Medicine, Shanghai, China.
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Gerzanich V, Stokum JA, Ivanova S, Woo SK, Tsymbalyuk O, Sharma A, Akkentli F, Imran Z, Aarabi B, Sahuquillo J, Simard JM. Sulfonylurea Receptor 1, Transient Receptor Potential Cation Channel Subfamily M Member 4, and KIR6.2:Role in Hemorrhagic Progression of Contusion. J Neurotrauma 2018; 36:1060-1079. [PMID: 30160201 PMCID: PMC6446209 DOI: 10.1089/neu.2018.5986] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
In severe traumatic brain injury (TBI), contusions often are worsened by contusion expansion or hemorrhagic progression of contusion (HPC), which may double the original contusion volume and worsen outcome. In humans and rodents with contusion-TBI, sulfonylurea receptor 1 (SUR1) is upregulated in microvessels and astrocytes, and in rodent models, blockade of SUR1 with glibenclamide reduces HPC. SUR1 does not function by itself, but must co-assemble with either KIR6.2 or transient receptor potential cation channel subfamily M member 4 (TRPM4) to form KATP (SUR1-KIR6.2) or SUR1-TRPM4 channels, with the two having opposite effects on membrane potential. Both KIR6.2 and TRPM4 are reportedly upregulated in TBI, especially in astrocytes, but the identity and function of SUR1-regulated channels post-TBI is unknown. Here, we analyzed human and rat brain tissues after contusion-TBI to characterize SUR1, TRPM4, and KIR6.2 expression, and in the rat model, to examine the effects on HPC of inhibiting expression of the three subunits using intravenous antisense oligodeoxynucleotides (AS-ODN). Glial fibrillary acidic protein (GFAP) immunoreactivity was used to operationally define core versus penumbral tissues. In humans and rats, GFAP-negative core tissues contained microvessels that expressed SUR1 and TRPM4, whereas GFAP-positive penumbral tissues contained astrocytes that expressed all three subunits. Förster resonance energy transfer imaging demonstrated SUR1-TRPM4 heteromers in endothelium, and SUR1-TRPM4 and SUR1-KIR6.2 heteromers in astrocytes. In rats, glibenclamide as well as AS-ODN targeting SUR1 and TRPM4, but not KIR6.2, reduced HPC at 24 h post-TBI. Our findings demonstrate upregulation of SUR1-TRPM4 and KATP after contusion-TBI, identify SUR1-TRPM4 as the primary molecular mechanism that accounts for HPC, and indicate that SUR1-TRPM4 is a crucial target of glibenclamide.
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Affiliation(s)
- Volodymyr Gerzanich
- 1 Department of Neurosurgery, University of Maryland School of Medicine, Baltimore, Maryland
| | - Jesse A Stokum
- 1 Department of Neurosurgery, University of Maryland School of Medicine, Baltimore, Maryland
| | - Svetlana Ivanova
- 1 Department of Neurosurgery, University of Maryland School of Medicine, Baltimore, Maryland
| | - Seung Kyoon Woo
- 1 Department of Neurosurgery, University of Maryland School of Medicine, Baltimore, Maryland
| | - Orest Tsymbalyuk
- 1 Department of Neurosurgery, University of Maryland School of Medicine, Baltimore, Maryland
| | - Amit Sharma
- 1 Department of Neurosurgery, University of Maryland School of Medicine, Baltimore, Maryland
| | - Fatih Akkentli
- 1 Department of Neurosurgery, University of Maryland School of Medicine, Baltimore, Maryland
| | - Ziyan Imran
- 1 Department of Neurosurgery, University of Maryland School of Medicine, Baltimore, Maryland
| | - Bizhan Aarabi
- 1 Department of Neurosurgery, University of Maryland School of Medicine, Baltimore, Maryland
| | - Juan Sahuquillo
- 2 Neurotraumatology and Neurosurgery Research Unit, Vall d'Hebron University Hospital, Universitat Autònoma de Barcelona, Barcelona, Spain.,3 Department of Neurosurgery, Vall d'Hebron University Hospital, Universitat Autònoma de Barcelona, Barcelona, Spain
| | - J Marc Simard
- 1 Department of Neurosurgery, University of Maryland School of Medicine, Baltimore, Maryland.,4 Department of Pathology, University of Maryland School of Medicine, Baltimore, Maryland.,5 Department of Physiology, University of Maryland School of Medicine, Baltimore, Maryland
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Hoeker GS, Skarsfeldt MA, Jespersen T, Poelzing S. Electrophysiologic effects of the IK1 inhibitor PA-6 are modulated by extracellular potassium in isolated guinea pig hearts. Physiol Rep 2017; 5:e13120. [PMID: 28087819 PMCID: PMC5256165 DOI: 10.14814/phy2.13120] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2016] [Accepted: 12/14/2016] [Indexed: 12/02/2022] Open
Abstract
The pentamidine analog PA-6 was developed as a specific inward rectifier potassium current (IK1) antagonist, because established inhibitors either lack specificity or have side effects that prohibit their use in vivo. We previously demonstrated that BaCl2, an established IK1 inhibitor, could prolong action potential duration (APD) and increase cardiac conduction velocity (CV). However, few studies have addressed whether targeted IK1 inhibition similarly affects ventricular electrophysiology. The aim of this study was to determine the effects of PA-6 on cardiac repolarization and conduction in Langendorff-perfused guinea pig hearts. PA-6 (200 nm) or vehicle was perfused into ex-vivo guinea pig hearts for 60 min. Hearts were optically mapped with di-4-ANEPPS to quantify CV and APD at 90% repolarization (APD90). Ventricular APD90 was significantly prolonged in hearts treated with PA-6 (115 ± 2% of baseline; P < 0.05), but not vehicle (105 ± 2% of baseline). PA-6 slightly, but significantly, increased transverse CV by 7%. PA-6 significantly prolonged APD90 during hypokalemia (2 mmol/L [K+]o), although to a lesser degree than observed at 4.56 mmol/L [K+]o In contrast, the effect of PA-6 on CV was more pronounced during hypokalemia, where transverse CV with PA-6 (24 ± 2 cm/sec) was significantly faster than with vehicle (13 ± 3 cm/sec, P < 0.05). These results show that under normokalemic conditions, PA-6 significantly prolonged APD90, whereas its effect on CV was modest. During hypokalemia, PA-6 prolonged APD90 to a lesser degree, but profoundly increased CV Thus, in intact guinea pig hearts, the electrophysiologic effects of the IK1 inhibitor, PA-6, are [K+]o-dependent.
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Affiliation(s)
- Gregory S Hoeker
- Biomedical Engineering and Mechanics, Center for Heart and Regenerative Medicine, Virginia Tech Virginia Tech Carilion Research Institute, Roanoke, Virginia
| | - Mark A Skarsfeldt
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Thomas Jespersen
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Steven Poelzing
- Biomedical Engineering and Mechanics, Center for Heart and Regenerative Medicine, Virginia Tech Virginia Tech Carilion Research Institute, Roanoke, Virginia
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Nelson PT, Katsumata Y, Nho K, Artiushin SC, Jicha GA, Wang WX, Abner EL, Saykin AJ, Kukull WA, Fardo DW. Genomics and CSF analyses implicate thyroid hormone in hippocampal sclerosis of aging. Acta Neuropathol 2016; 132:841-858. [PMID: 27815632 DOI: 10.1007/s00401-016-1641-2] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2016] [Revised: 10/28/2016] [Accepted: 10/28/2016] [Indexed: 11/29/2022]
Abstract
We report evidence of a novel pathogenetic mechanism in which thyroid hormone dysregulation contributes to dementia in elderly persons. Two single nucleotide polymorphisms (SNPs) on chromosome 12p12 were the initial foci of our study: rs704180 and rs73069071. These SNPs were identified by separate research groups as risk alleles for non-Alzheimer's neurodegeneration. We found that the rs73069071 risk genotype was associated with hippocampal sclerosis (HS) pathology among people with the rs704180 risk genotype (National Alzheimer's Coordinating Center/Alzheimer's Disease Genetic Consortium data; n = 2113, including 241 autopsy-confirmed HS cases). Furthermore, both rs704180 and rs73069071 risk genotypes were associated with widespread brain atrophy visualized by MRI (Alzheimer's Disease Neuroimaging Initiative data; n = 1239). In human brain samples from the Braineac database, both rs704180 and rs73069071 risk genotypes were associated with variation in expression of ABCC9, a gene which encodes a metabolic sensor protein in astrocytes. The rs73069071 risk genotype was also associated with altered expression of a nearby astrocyte-expressed gene, SLCO1C1. Analyses of human brain gene expression databases indicated that the chromosome 12p12 locus may regulate particular astrocyte-expressed genes induced by the active form of thyroid hormone, triiodothyronine (T3). This is informative biologically, because the SLCO1C1 protein transports thyroid hormone into astrocytes from blood. Guided by the genomic data, we tested the hypothesis that altered thyroid hormone levels could be detected in cerebrospinal fluid (CSF) obtained from persons with HS pathology. Total T3 levels in CSF were elevated in HS cases (p < 0.04 in two separately analyzed groups), but not in Alzheimer's disease cases, relative to controls. No change was detected in the serum levels of thyroid hormone (T3 or T4) in a subsample of HS cases prior to death. We conclude that brain thyroid hormone perturbation is a potential pathogenetic factor in HS that may also provide the basis for a novel CSF-based clinical biomarker.
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11
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Wu Y, He MY, Ye JK, Ma SY, Huang W, Wei YY, Kong H, Wang H, Zeng XN, Xie WP. Activation of ATP-sensitive potassium channels facilitates the function of human endothelial colony-forming cells via Ca 2+ /Akt/eNOS pathway. J Cell Mol Med 2016; 21:609-620. [PMID: 27709781 PMCID: PMC5323860 DOI: 10.1111/jcmm.13006] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2016] [Accepted: 09/05/2016] [Indexed: 12/17/2022] Open
Abstract
Accumulating data, including those from our laboratory, have shown that the opening of ATP‐sensitive potassium channels (KATP) plays a protective role in pulmonary vascular diseases (PVD). As maintainers of the endothelial framework, endothelial colony‐forming cells (ECFCs) are considered excellent candidates for vascular regeneration in cases of PVD. Although KATP openers (KCOs) have been demonstrated to have beneficial effects on endothelial cells, the impact of KATP on ECFC function remains unclear. Herein, this study investigated whether there is a distribution of KATP in ECFCs and what role KATP play in ECFC modulation. By human ECFCs isolated from adult peripheral blood, KATP were confirmed for the first time to express in ECFCs, comprised subunits of Kir (Kir6.1, Kir6.2) and SUR2b. KCOs such as the classical agent nicorandil (Nico) and the novel agent iptakalim (Ipt) notably improved the function of ECFCs, promoting cell proliferation, migration and angiogenesis, which were abolished by a non‐selective KATP blocker glibenclamide (Gli). To determine the underlying mechanisms, we investigated the impacts of KCOs on CaMKII, Akt and endothelial nitric oxide synthase pathways. Enhanced levels were detected by western blotting, which were abrogated by Gli. This suggested an involvement of Ca2+ signalling in the regulation of ECFCs by KATP. Our findings demonstrated for the first time that there is a distribution of KATP in ECFCs and KATP play a vital role in ECFC function. The present work highlighted a novel profile of KATP as a potential target for ECFC modulation, which may hold the key to the treatment of PVD.
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Affiliation(s)
- Yan Wu
- Department of Respiratory Medicine, WuXi People's Hospital Affiliated to Nanjing Medical University, Wuxi, Jiangsu, China
| | - Meng-Yu He
- Department of Respiratory and Critical Care Medicine, The First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu, China
| | - Jian-Kui Ye
- Department of Respiratory and Critical Care Medicine, The First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu, China
| | - Shu-Ying Ma
- Department of Respiratory and Critical Care Medicine, The First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu, China
| | - Wen Huang
- Department of Respiratory and Critical Care Medicine, The First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu, China
| | - Yong-Yue Wei
- Department of Biostatistics, School of Public Health, Nanjing Medical University, Nanjing, Jiangsu, China
| | - Hui Kong
- Department of Respiratory and Critical Care Medicine, The First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu, China
| | - Hong Wang
- Department of Respiratory and Critical Care Medicine, The First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu, China
| | - Xiao-Ning Zeng
- Department of Respiratory and Critical Care Medicine, The First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu, China
| | - Wei-Ping Xie
- Department of Respiratory and Critical Care Medicine, The First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu, China
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12
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Mitragynine and its potential blocking effects on specific cardiac potassium channels. Toxicol Appl Pharmacol 2016; 305:22-39. [PMID: 27260674 DOI: 10.1016/j.taap.2016.05.022] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2016] [Revised: 05/30/2016] [Accepted: 05/31/2016] [Indexed: 02/07/2023]
Abstract
Mitragyna speciosa Korth is known for its euphoric properties and is frequently used for recreational purposes. Several poisoning and fatal cases involving mitragynine have been reported but the underlying causes remain unclear. Human ether-a-go-go-related gene (hERG) encodes the cardiac IKr current which is a determinant of the duration of ventricular action potentials and QT interval. On the other hand, IK1, a Kir current mediated by Kir2.1 channel and IKACh, a receptor-activated Kir current mediated by GIRK channel are also known to be important in maintaining the cardiac function. This study investigated the effects of mitragynine on the current, mRNA and protein expression of hERG channel in hERG-transfected HEK293 cells and Xenopus oocytes. The effects on Kir2.1 and GIRK channels currents were also determined in the oocytes. The hERG tail currents following depolarization pulses were inhibited by mitragynine with an IC50 value of 1.62μM and 1.15μM in the transfected cell line and Xenopus oocytes, respectively. The S6 point mutations of Y652A and F656A attenuated the inhibitor effects of mitragynine, indicating that mitragynine interacts with these high affinity drug-binding sites in the hERG channel pore cavity which was consistent with the molecular docking simulation. Interestingly, mitragynine does not affect the hERG expression at the transcriptional level but inhibits the protein expression. Mitragynine is also found to inhibit IKACh current with an IC50 value of 3.32μM but has no significant effects on IK1. Blocking of both hERG and GIRK channels may cause additive cardiotoxicity risks.
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Abstract
Any disturbance of electrical impulse formation in the heart and of impulse conduction or action potential (AP) repolarization can lead to rhythm disorders. Potassium (K(+)) channels play a prominent role in the AP repolarization process. In this review we describe the causes and mechanisms of proarrhythmic effects that arise as a response to blockers of cardiac K(+) channels. The largest and chemically most diverse groups of compound targets are Kv11.1 (hERG) and Kv7.1 (KvLQT1) channels. Finally, the proarrhythmic propensity of atrial-selective K(+) blockers inhibiting Kv1.5, Kir3.1/3.4, SK, and K2P channels is discussed.
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Affiliation(s)
- Lasse Skibsbye
- Danish Arrhythmia Research Centre, Faculty of Health and Medical Sciences, University of Copenhagen, 3 Blegdamsvej, 3 Copenhagen N DK-2200, Denmark
| | - Ursula Ravens
- Department of Pharmacology and Toxicology, Medical Faculty Carl Gustav Carus, Institut für Pharmakologie und Toxikologie, TU Dresden, Fetscherstrasse 74, Dresden D-01307, Germany.
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14
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Harrouche K, Renard JF, Bouider N, de Tullio P, Goffin E, Lebrun P, Faury G, Pirotte B, Khelili S. Synthesis, characterization and biological evaluation of benzothiazoles and tetrahydrobenzothiazoles bearing urea or thiourea moieties as vasorelaxants and inhibitors of the insulin releasing process. Eur J Med Chem 2016; 115:352-60. [PMID: 27031211 DOI: 10.1016/j.ejmech.2016.03.028] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2015] [Revised: 03/07/2016] [Accepted: 03/10/2016] [Indexed: 10/22/2022]
Abstract
A series of 1,3-benzothiazoles (series I) and 4,5,6,7-tetrahydro-1,3-benzothiazoles (series II) bearing an urea or a thiourea moiety at the 2-position were synthesized and tested as myorelaxants and inhibitors of insulin secretion. Several compounds (i.e. 13u and 13v) from series I showed a marked myorelaxant activity. Benzothiazoles bearing a strong electron withdrawing group (NO2, CN) at the 6-position and an alkyl group linked to the urea or the thiourea function at the 2-position were found to be the most potent compounds. The weak vasorelaxant activity of series II compounds evidenced the necessity of the presence of a complete aromatic heterocyclic system. The myorelaxant activity of some active compounds was reduced when measured on aorta rings precontracted by 80 mM KCl or by 30 mM KCl in the presence of 10 μM glibenclamide, suggesting the involvement of KATP channels in the vasorelaxant effect. Some compounds of series I tested on rat pancreatic islets provoked a marked inhibition of insulin secretion, among which 13a exhibited a clear tissue selectivity for pancreatic β-cells.
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Affiliation(s)
- Kamel Harrouche
- Laboratoire de Phytochimie et de Pharmacologie, Département de Chimie, Faculté des Sciences Exactes et Informatique, Université Mohamed Seddik Ben Yahia Jijel, B.P. 98 Ouled Aissa, 18000 Jijel, Algeria
| | - Jean-Francois Renard
- Laboratoire de Chimie Pharmaceutique, Center for Interdisciplinary Research on Medicines (CIRM), Université de Liège, 1, Avenue de l'Hôpital, B-4000 Liège, Belgium
| | - Nafila Bouider
- Laboratoire de Phytochimie et de Pharmacologie, Département de Chimie, Faculté des Sciences Exactes et Informatique, Université Mohamed Seddik Ben Yahia Jijel, B.P. 98 Ouled Aissa, 18000 Jijel, Algeria
| | - Pascal de Tullio
- Laboratoire de Chimie Pharmaceutique, Center for Interdisciplinary Research on Medicines (CIRM), Université de Liège, 1, Avenue de l'Hôpital, B-4000 Liège, Belgium
| | - Eric Goffin
- Laboratoire de Chimie Pharmaceutique, Center for Interdisciplinary Research on Medicines (CIRM), Université de Liège, 1, Avenue de l'Hôpital, B-4000 Liège, Belgium
| | - Philippe Lebrun
- Laboratoire de Physiologie et Pharmacologie, Université Libre de Bruxelles, Faculté de Médecine, 808, Route de Lennik, B-1070 Bruxelles, Belgium
| | - Gilles Faury
- Laboratoire "Hypoxie: Physiopathologie Cardiovasculaire et Respiratoire" (HP2), INSERM U1042-Université Grenoble Alpes, F-38042 La Tronche, France
| | - Bernard Pirotte
- Laboratoire de Chimie Pharmaceutique, Center for Interdisciplinary Research on Medicines (CIRM), Université de Liège, 1, Avenue de l'Hôpital, B-4000 Liège, Belgium.
| | - Smail Khelili
- Laboratoire de Phytochimie et de Pharmacologie, Département de Chimie, Faculté des Sciences Exactes et Informatique, Université Mohamed Seddik Ben Yahia Jijel, B.P. 98 Ouled Aissa, 18000 Jijel, Algeria
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15
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Stokum JA, Gerzanich V, Simard JM. Molecular pathophysiology of cerebral edema. J Cereb Blood Flow Metab 2016; 36:513-38. [PMID: 26661240 PMCID: PMC4776312 DOI: 10.1177/0271678x15617172] [Citation(s) in RCA: 357] [Impact Index Per Article: 44.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/11/2015] [Revised: 10/21/2015] [Accepted: 10/22/2015] [Indexed: 12/25/2022]
Abstract
Advancements in molecular biology have led to a greater understanding of the individual proteins responsible for generating cerebral edema. In large part, the study of cerebral edema is the study of maladaptive ion transport. Following acute CNS injury, cells of the neurovascular unit, particularly brain endothelial cells and astrocytes, undergo a program of pre- and post-transcriptional changes in the activity of ion channels and transporters. These changes can result in maladaptive ion transport and the generation of abnormal osmotic forces that, ultimately, manifest as cerebral edema. This review discusses past models and current knowledge regarding the molecular and cellular pathophysiology of cerebral edema.
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Affiliation(s)
- Jesse A Stokum
- Department of Neurosurgery, University of Maryland School of Medicine, Baltimore, USA
| | - Volodymyr Gerzanich
- Department of Neurosurgery, University of Maryland School of Medicine, Baltimore, USA
| | - J Marc Simard
- Department of Neurosurgery, University of Maryland School of Medicine, Baltimore, USA Department of Pathology, University of Maryland School of Medicine, Baltimore, USA Department of Physiology, University of Maryland School of Medicine, Baltimore, USA
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16
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Abstract
KATP channels are integral to the functions of many cells and tissues. The use of electrophysiological methods has allowed for a detailed characterization of KATP channels in terms of their biophysical properties, nucleotide sensitivities, and modification by pharmacological compounds. However, even though they were first described almost 25 years ago (Noma 1983, Trube and Hescheler 1984), the physiological and pathophysiological roles of these channels, and their regulation by complex biological systems, are only now emerging for many tissues. Even in tissues where their roles have been best defined, there are still many unanswered questions. This review aims to summarize the properties, molecular composition, and pharmacology of KATP channels in various cardiovascular components (atria, specialized conduction system, ventricles, smooth muscle, endothelium, and mitochondria). We will summarize the lessons learned from available genetic mouse models and address the known roles of KATP channels in cardiovascular pathologies and how genetic variation in KATP channel genes contribute to human disease.
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Affiliation(s)
- Monique N Foster
- Departments of Pediatrics, Physiology & Neuroscience, and Biochemistry and Molecular Pharmacology, NYU School of Medicine, New York, New York
| | - William A Coetzee
- Departments of Pediatrics, Physiology & Neuroscience, and Biochemistry and Molecular Pharmacology, NYU School of Medicine, New York, New York
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17
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Maiti P, Manna J, Ilavazhagan G, Rossignol J, Dunbar GL. Molecular regulation of dendritic spine dynamics and their potential impact on synaptic plasticity and neurological diseases. Neurosci Biobehav Rev 2015; 59:208-37. [PMID: 26562682 DOI: 10.1016/j.neubiorev.2015.09.020] [Citation(s) in RCA: 83] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2015] [Revised: 08/20/2015] [Accepted: 09/07/2015] [Indexed: 12/12/2022]
Abstract
The structure and dynamics of dendritic spines reflect the strength of synapses, which are severely affected in different brain diseases. Therefore, understanding the ultra-structure, molecular signaling mechanism(s) regulating dendritic spine dynamics is crucial. Although, since last century, dynamics of spine have been explored by several investigators in different neurological diseases, but despite countless efforts, a comprehensive understanding of the fundamental etiology and molecular signaling pathways involved in spine pathology is lacking. The purpose of this review is to provide a contextual framework of our current understanding of the molecular mechanisms of dendritic spine signaling, as well as their potential impact on different neurodegenerative and psychiatric diseases, as a format for highlighting some commonalities in function, as well as providing a format for new insights and perspectives into this critical area of research. Additionally, the potential strategies to restore spine structure-function in different diseases are also pointed out. Overall, these informations should help researchers to design new drugs to restore the structure-function of dendritic spine, a "hot site" of synaptic plasticity.
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Affiliation(s)
- Panchanan Maiti
- Field Neurosciences Institute, St. Mary's of Michigan, Saginaw, MI, USA; Department of Psychology and Neurosciences Program, Central Michigan University, Mt. Pleasant, MI, USA.
| | - Jayeeta Manna
- Department of Physiology, University of Tennessee Health Science Center, Memphis, TN, USA.
| | - G Ilavazhagan
- Hindustan University, Rajiv Gandhi Salai (OMR), Padur, Kelambakam, Chennai, TN, India.
| | - Julien Rossignol
- Department of Psychology and Neurosciences Program, Central Michigan University, Mt. Pleasant, MI, USA; College of Medicine, Central Michigan University, Mt. Pleasant, MI, USA.
| | - Gary L Dunbar
- Field Neurosciences Institute, St. Mary's of Michigan, Saginaw, MI, USA; Department of Psychology and Neurosciences Program, Central Michigan University, Mt. Pleasant, MI, USA.
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18
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Jovanović S, Ballantyne T, Du Q, Blagojević M, Jovanović A. Phenylephrine preconditioning in embryonic heart H9c2 cells is mediated by up-regulation of SUR2B/Kir6.2: A first evidence for functional role of SUR2B in sarcolemmal KATP channels and cardioprotection. Int J Biochem Cell Biol 2015; 70:23-8. [PMID: 26556311 PMCID: PMC4711337 DOI: 10.1016/j.biocel.2015.10.029] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2015] [Revised: 10/22/2015] [Accepted: 10/30/2015] [Indexed: 02/07/2023]
Abstract
ATP-sensitive K+ (KATP) channels were originally described in cardiomyocytes, where physiological levels of intracellular ATP keep them in a closed state. Structurally, these channels are composed of pore-forming inward rectifier, Kir6.1 or Kir6.2, and a regulatory, ATP-binding subunit, SUR1, SUR2A or SUR2B. SUR1 and Kir6.2 form pancreatic type of KATP channels, SUR2A and Kir6.2 form cardiac type of KATP channels, SUR2B and Kir6.1 form vascular smooth muscle type of KATP channels. The presence of SUR2B has been described in cardiomyocytes, but its functional significance and role has remained unknown. Pretreatment with phenylephrine (100 nM) for 24 h increased mRNA levels of SUR2B and Kir6.2, without affecting those levels of SUR1, SUR2A and Kir6.1 in embryonic heart H9c2 cells. Such increase was associated with increased K+ current through KATP channels and Kir6.2/SUR2B protein complexes as revealed by whole cell patch clamp electrophysiology and immunoprecipitation/Western blotting respectively. Pretreatment with phenylephrine (100 nM) generated a cellular phenotype that acquired resistance to chemical hypoxia induced by 2,4-dinitrophenol (DNP; 10 mM), which was accompanied by increased in K+ current in response to DNP (10 mM). Cytoprotection afforded by phenylephrine (100 nM) was abolished by infection of H9c2 cells with adenovirus containing Kir6.2AFA, a mutant form of Kir6.2 with largely reduced K+ conductance. Taking all together, the present findings demonstrate that the activation of α1-adrenoceptors up-regulates SUR2B/Kir6.2 to confer cardioprotection. This is the first account of possible physiological role of SUR2B in cardiomyocytes.
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Affiliation(s)
- Sofija Jovanović
- Medical Research Institute, Division of Cardiovascular & Diabetic Medicine, Ninewells Hospital & Medical School, University of Dundee, UK
| | - Thomas Ballantyne
- Medical Research Institute, Division of Cardiovascular & Diabetic Medicine, Ninewells Hospital & Medical School, University of Dundee, UK
| | - Qingyou Du
- Medical Research Institute, Division of Cardiovascular & Diabetic Medicine, Ninewells Hospital & Medical School, University of Dundee, UK
| | - Miloš Blagojević
- Department of Anatomy, Faculty of Veterinary Medicine, University of Belgrade, Belgrade, Serbia
| | - Aleksandar Jovanović
- Medical Research Institute, Division of Cardiovascular & Diabetic Medicine, Ninewells Hospital & Medical School, University of Dundee, UK.
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19
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The protective effect of Na+/Ca2+ exchange blocker kb-r7943 on myocardial ischemia-reperfusion injury in hypercholesterolemic rat. Cell Biochem Biophys 2015; 70:1017-22. [PMID: 24840224 DOI: 10.1007/s12013-014-0012-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
KB-R7943 reduces lethal reperfusion injury under normal conditions, but its effectiveness under certain pathological states is in dispute. In the present study, we sought to determine the effect of KB-R7943 in hyperlipidemic animals and assess if the K ATP (+) are involved in the protective mechanisms. In group 1 (G1), isolated rat hearts underwent 25 min global ischemia (GI) and 120 min reperfusion (R). In group 2 (G2), G1 was repeated but the animals were subjected to a 1.5 % cholesterol-enriched diet during 6 weeks (hypercholesterolemic animals). In group 3 (G3), G2 was repeated but 1 μM KB-R7943 was added to the perfusate for 10 min from the start of reperfusion. In group 4 (G4), G3 was repeated, and glibenclamide (K ATP (+) , blocker, 0.3 μM) was administered. The infarct size was measured by triphenyltetrazolium. The infarct size was 35 ± 5.0 % in G1 and 46 ± 8.7 % in G2 (P < 0.05); KB-R7943 reduced the infarct size (28.6 ± 3.3 % in G3 vs. G2, P < 0.05). In addition, KB-R7943 attenuated apoptotic cell (G3 vs. G2, P < 0.05), but glibenclamide abolished the effect reached by KB-R7943. Thus, diet-induced hypercholesterolemia enhances myocardial injury; KB-R7943 reduces infarct size and apoptosis in hyperlipidemic animals through the activation of K(+)ATP channels.
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20
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Zhang Q, Bai Y, Yang Z, Tian J, Meng Z. The molecular mechanisms of sodium metabisulfite on the expression of K ATP and L-Ca2+ channels in rat hearts. Regul Toxicol Pharmacol 2015; 72:440-6. [PMID: 26015265 DOI: 10.1016/j.yrtph.2015.05.021] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2014] [Revised: 03/13/2015] [Accepted: 05/19/2015] [Indexed: 11/18/2022]
Abstract
Sodium metabisulfite (SMB) is used as an antioxidant and antimicrobial agent in a variety of drugs and foods. However, there are few reported studies about its side effects. This study is to investigate the SMB effects on the expression of ATP-sensitive K(+) (KATP) and L-type calcium (L-Ca(2+)) channels in rat hearts. The results show that the mRNA and protein levels of the KATP channel subunits Kir6.2 and SUR2A were increased by SMB; on the contrary, SMB at 520 mg/kg significantly decreased the expression of the L-Ca(2+) channel subunits Cav1.2 and Cav1.3. This suggests that SMB can activate the expression of KATP channel by increasing the mRNA and protein levels of Kir6.2 and SUR2A, while it inhibits the expression of L-Ca(2+) channels by decreasing the mRNA and protein levels of Cav1.2 and Cav1.3 in rat hearts. Therefore, the molecular mechanism of the SMB effect on rat hearts might be related to the increased expression of KATP channels and the decreased expression of L-Ca(2+) channels.
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Affiliation(s)
- Quanxi Zhang
- Institute of Environmental Medicine and Toxicology, Institute of Environmental Science, Shanxi University, Taiyuan 030006, China.
| | - Yunlong Bai
- Institute of Environmental Medicine and Toxicology, Institute of Environmental Science, Shanxi University, Taiyuan 030006, China
| | - Zhenhua Yang
- Institute of Environmental Medicine and Toxicology, Institute of Environmental Science, Shanxi University, Taiyuan 030006, China
| | - Jingjing Tian
- Institute of Environmental Medicine and Toxicology, Institute of Environmental Science, Shanxi University, Taiyuan 030006, China
| | - Ziqiang Meng
- Institute of Environmental Medicine and Toxicology, Institute of Environmental Science, Shanxi University, Taiyuan 030006, China
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21
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Wang C, Hu SM, Xie H, Qiao SG, Liu H, Liu CF. Role of mitochondrial ATP-sensitive potassium channel-mediated PKC-ε in delayed protection against myocardial ischemia/reperfusion injury in isolated hearts of sevoflurane-preconditioned rats. ACTA ACUST UNITED AC 2015; 48:528-36. [PMID: 25831209 PMCID: PMC4470312 DOI: 10.1590/1414-431x20143876] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2014] [Accepted: 10/07/2014] [Indexed: 01/23/2023]
Abstract
This study aimed to determine the role of mitochondrial adenosine
triphosphate-sensitive potassium (mitoKATP) channels and protein kinase C
(PKC)-ε in the delayed protective effects of sevoflurane preconditioning using
Langendorff isolated heart perfusion models. Fifty-four isolated perfused rat hearts
were randomly divided into 6 groups (n=9). The rats were exposed for 60 min to 2.5%
sevoflurane (the second window of protection group, SWOP group) or 33% oxygen
inhalation (I/R group) 24 h before coronary occlusion. The control group (CON) and
the sevoflurane group (SEVO) group were exposed to 33% oxygen and 2.5% sevoflurane
for 60 min, respectively, without coronary occlusion. The mitoKATP channel
inhibitor 5-hydroxydecanoate (5-HD) was given 30 min before sevoflurane
preconditioning (5-HD+SWOP group). Cardiac function indices, infarct sizes, serum
cardiac troponin I (cTnI) concentrations, and the expression levels of phosphorylated
PKC-ε (p-PKC-ε) and caspase-8 were measured. Cardiac function was unchanged, p-PKC-ε
expression was upregulated, caspase-8 expression was downregulated, cTnI
concentrations were decreased, and the infarcts were significantly smaller
(P<0.05) in the SWOP group compared with the I/R group. Cardiac function was
worse, p-PKC-ε expression was downregulated, caspase-8 expression was upregulated,
cTnI concentration was increased and infarcts were larger in the 5-HD+SWOP group
(P<0.05) compared with the SWOP group. The results suggest that
mitoKATP channels are involved in the myocardial protective effects of
sevoflurane in preconditioning against I/R injury, by regulating PKC-ε
phosphorylation before ischemia, and by downregulating caspase-8 during
reperfusion.
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Affiliation(s)
- C Wang
- Department of Anesthesiology and Critical Care, The Second Affiliate Hospital, Soochow University, Suzhou, China
| | - S M Hu
- Institute of Neuroscience, Soochow University, Suzhou, China
| | - H Xie
- Department of Anesthesiology and Critical Care, The Second Affiliate Hospital, Soochow University, Suzhou, China
| | - S G Qiao
- Department of Anesthesiology and Critical Care, The Second Affiliate Hospital, Soochow University, Suzhou, China
| | - H Liu
- Department of Anesthesiology and Pain Medicine, University of California Davis Health System, Davis, CA, USA
| | - C F Liu
- Institute of Neuroscience, Soochow University, Suzhou, China
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22
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Isgaard J, Arcopinto M, Karason K, Cittadini A. GH and the cardiovascular system: an update on a topic at heart. Endocrine 2015; 48:25-35. [PMID: 24972804 PMCID: PMC4328125 DOI: 10.1007/s12020-014-0327-6] [Citation(s) in RCA: 72] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/02/2014] [Accepted: 06/04/2014] [Indexed: 01/06/2023]
Abstract
In this review, the importance of growth hormone (GH) for the maintenance of normal cardiac function in adult life is discussed. Physiological effects of GH and underlying mechanisms for interactions between GH and insulin-like growth factor I (IGF-I) and the cardiovascular system are covered as well as the cardiac dysfunction caused both by GH excess (acromegaly) and by GH deficiency in adult hypopituitary patients. In both acromegaly and adult GH deficiency, there is also increased cardiovascular morbidity and mortality possibly linked to aberrations in GH status. Finally, the status of the GH/IGF-I system in relation to heart failure and the potential of GH as a therapeutic tool in the treatment of heart failure are reviewed in this article.
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Affiliation(s)
- Jörgen Isgaard
- Laboratory of Experimental Endocrinology, Department of Internal Medicine, Sahlgrenska Academy, University of Gothenburg, Gröna Stråket 8, 413 45, Göteborg, Sweden,
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23
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Sun Y, Huang Y, Zhang R, Chen Q, Chen J, Zong Y, Liu J, Feng S, Liu AD, Holmberg L, Liu D, Tang C, Du J, Jin H. Hydrogen sulfide upregulates KATP channel expression in vascular smooth muscle cells of spontaneously hypertensive rats. J Mol Med (Berl) 2014; 93:439-55. [PMID: 25412775 DOI: 10.1007/s00109-014-1227-1] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2014] [Revised: 10/26/2014] [Accepted: 11/03/2014] [Indexed: 01/23/2023]
Abstract
UNLABELLED The study was designed to investigate whether H2S could upregulate expression of KATP channels in vascular smooth muscle cells (VSMCs), and by this mechanism enhances vasorelaxation in spontaneously hypertensive rats (SHR). Blood pressure, vascular structure, and vasorelaxation were analyzed. Plasma H2S was detected using polarographic sensor. SUR2B and Kir6.1 expressions were detected in VSMCs of SHR and in A7r5 cells as well as primarily cultured ASMCs using real-time PCR, western blot, immunofluorescence, and confocal imaging. Nuclear translocation of forkhead transcription factors FOXO1 and FOXO3a in ASMCs was detected using laser confocal microscopy, and their binding activity with SUR2B and Kir6.1 promoters was examined by chromatin immunoprecipitation. SHR developed hypertension at 18 weeks. They showed downregulated vascular SUR2B and Kir6.1 expressions in association with a decreased plasma H2S level. H2S donor, however, could upregulate vascular SUR2B and Kir6.1 expressions, causing a left shift of the vasorelaxation curve to pinacidil and lowered tail artery pressure in the SHR. Also, H2S antagonized endothelin-1 (ET-1)-inhibited KATP expression in A7r5 cells and cultured ASMCs. Mechanistically, H2S inhibited ET-1-stimulated p-FOXO1 and p-FOXO3a expressions (inactivated forms), but increased their nuclear translocation and the ET-1-inhibited binding of FOXO1 and FOXO3a with Kir6.1 and SUR2B promoters in ASMCs. Hence, H2S promotes vasorelaxation of SHR, at least in part, through upregulating the expression of KATP subunits by inhibiting phosphorylation of FOXO1 and FOXO3a, and stimulating FOXO1 and FOXO3a nuclear translocation and their binding activity with SUR2B and Kir6.1 promoters. KEY MESSAGES H2S increased vascular SUR2B and Kir6.1 expression of SHR, promoting vasorelaxation. H2S antagonized ET-1-inhibited KATP expression in A7r5 cells and cultured ASMCs. H2S inhibited ET-1-induced FOXO1 and FOXO3a phosphorylation in ASMCs. H2S promoted FOXO1 and FOXO3a nuclear translocation and binding with target gene promoters.
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Affiliation(s)
- Yan Sun
- Department of Pediatrics, Peking University First Hospital, Xi-An Men Street No. 1, West District, Beijing, 100034, China
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24
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Protective effect of Na(+)/Ca (2+) exchange blocker KB-R7943 on myocardial ischemia-reperfusion injury in hypercholesterolemic rats. Cell Biochem Biophys 2013; 66:357-63. [PMID: 23212178 DOI: 10.1007/s12013-012-9474-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Reverse-mode activation of the Na(+)/Ca(2+) exchanger (NCX) during reperfusion following ischemia contributes to Ca(2+) overload and cardiomyocyte injury. KB-R7943, a selective reverse-mode NCX inhibitor, reduces lethal reperfusion injury under non-ischemic conditions. However, the effectiveness of this compound under ischemic conditions is unclear. In the present study, we studied the effects of KB-R7943 in an animal model of hyperlipidemia. We further assessed whether the K ATP (+) channels are involved in potential protective mechanisms of KB-R7943. Twelve rats were fed normal chow, while 48 animals were fed a high cholesterol diet. The hearts from the control and hypercholesterolemic rats were subjected to 25 min of global ischemia followed by a 120-min reperfusion. Before this, hearts from hypercholesterolemic rats either received no intervention (cholesterol control group) or were pre-treated with 1 μM KB-R7943 and 0.3 μM of K ATP (+) blocker glibenclamide or glibenclamide alone. The infarction sizes (triphenyltetrazolium assay) were 35 ± 5.0 % in the control group, 46 ± 8.7 % in the cholesterol control group (p < 0.05 vs. control group), 28.6 ± 3.3 % in the KB-R7943 group (p < 0.05 vs. cholesterol control group), 44 ± 5 % in the KB-R7943 and glibenclamide group, and 47 ± 8.5 % in the glibenclamide group (p < 0.05 vs. control group). Further, KB-R7943 attenuated the magnitude of cell apoptosis (p < 0.05 vs. cholesterol control group). These beneficial effects were abolished by glibenclamide. In conclusion, diet-induced hypercholesterolemia enhances myocardial injury. Selective reverse-mode NCX inhibitor KB-R7943 reduces the infarction size and apoptosis in hyperlipidemic animals through the activation of K ATP (+) channels.
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Shen M, Zhao L, Wu RX, Yue SQ, Pei JM. The vasorelaxing effect of resveratrol on abdominal aorta from rats and its underlying mechanisms. Vascul Pharmacol 2013; 58:64-70. [DOI: 10.1016/j.vph.2012.07.005] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2012] [Revised: 06/18/2012] [Accepted: 07/11/2012] [Indexed: 11/28/2022]
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Liu YH, Lu M, Hu LF, Wong PTH, Webb GD, Bian JS. Hydrogen sulfide in the mammalian cardiovascular system. Antioxid Redox Signal 2012; 17:141-85. [PMID: 22304473 DOI: 10.1089/ars.2011.4005] [Citation(s) in RCA: 197] [Impact Index Per Article: 16.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
For more than a century, hydrogen sulfide (H(2)S) has been regarded as a toxic gas. This review surveys the growing recognition of the role of H(2)S as an endogenous signaling molecule in mammals, with emphasis on its physiological and pathological pathways in the cardiovascular system. In biological fluids, H(2)S gas is a weak acid that exists as about 15% H(2)S, 85% HS(-), and a trace of S(2-). Here, we use "H(2)S" to refer to this mixture. H(2)S has been found to influence heart contractile functions and may serve as a cardioprotectant for treating ischemic heart diseases and heart failure. Alterations of the endogenous H(2)S level have been found in animal models with various pathological conditions such as myocardial ischemia, spontaneous hypertension, and hypoxic pulmonary hypertension. In the vascular system, H(2)S exerts biphasic regulation of a vascular tone with varying effects based on its concentration and in the presence of nitric oxide. Over the past decade, several H(2)S-releasing compounds (NaHS, Na(2)S, GYY4137, etc.) have been utilized to test the effect of exogenous H(2)S under different physiological and pathological situations in vivo and in vitro. H(2)S has been found to promote angiogenesis and to protect against atherosclerosis and hypertension, while excess H(2)S may promote inflammation in septic or hemorrhagic shock. H(2)S-releasing compounds and inhibitors of H(2)S synthesis hold promise in alleviating specific disease conditions. This comprehensive review covers in detail the effects of H(2)S on the cardiovascular system, especially in disease situations, and also the various underlying mechanisms.
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Affiliation(s)
- Yi-Hong Liu
- Department of Pharmacology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
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Abstract
Hydrogen sulfide (H2S) is an endogenous gasotransmitter produced in mammalian cells. It is responsible for physiological functions in many organs and systems, with attention focused mainly on the cardiovascular and nervous systems. In the vascular system, H2S produces biphasic effects in regulation of vascular tone. At lower concentrations, it induces vasoconstriction predominantly via decreasing cyclic adenosine monophosphate in smooth muscle cell and inhibiting the production and bioavailability of nitric oxide. At higher concentrations, it produces vasorelaxation mainly through opening of KATP channels and induction of intracellular acidification. Scavenging reactive oxygen species and elevation of cyclic guanosine monophosphate are also implicated in the vasorelaxant response. This review presents an overview of the current knowledge of H2S in the vascular system, with special emphasis and discussion on the involvement of various signaling pathways and ion channels based on current understanding and reported literature till date.
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Abstract
It has been known for more than 60 years, and suspected for over 100, that alveolar hypoxia causes pulmonary vasoconstriction by means of mechanisms local to the lung. For the last 20 years, it has been clear that the essential sensor, transduction, and effector mechanisms responsible for hypoxic pulmonary vasoconstriction (HPV) reside in the pulmonary arterial smooth muscle cell. The main focus of this review is the cellular and molecular work performed to clarify these intrinsic mechanisms and to determine how they are facilitated and inhibited by the extrinsic influences of other cells. Because the interaction of intrinsic and extrinsic mechanisms is likely to shape expression of HPV in vivo, we relate results obtained in cells to HPV in more intact preparations, such as intact and isolated lungs and isolated pulmonary vessels. Finally, we evaluate evidence regarding the contribution of HPV to the physiological and pathophysiological processes involved in the transition from fetal to neonatal life, pulmonary gas exchange, high-altitude pulmonary edema, and pulmonary hypertension. Although understanding of HPV has advanced significantly, major areas of ignorance and uncertainty await resolution.
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Affiliation(s)
- J. T. Sylvester
- Division of Pulmonary & Critical Care Medicine, Department of Medicine, The Johns Hopkins University School of Medicine, Baltimore, Maryland; and Division of Asthma, Allergy and Lung Biology, School of Medicine, King's College, London, United Kingdom
| | - Larissa A. Shimoda
- Division of Pulmonary & Critical Care Medicine, Department of Medicine, The Johns Hopkins University School of Medicine, Baltimore, Maryland; and Division of Asthma, Allergy and Lung Biology, School of Medicine, King's College, London, United Kingdom
| | - Philip I. Aaronson
- Division of Pulmonary & Critical Care Medicine, Department of Medicine, The Johns Hopkins University School of Medicine, Baltimore, Maryland; and Division of Asthma, Allergy and Lung Biology, School of Medicine, King's College, London, United Kingdom
| | - Jeremy P. T. Ward
- Division of Pulmonary & Critical Care Medicine, Department of Medicine, The Johns Hopkins University School of Medicine, Baltimore, Maryland; and Division of Asthma, Allergy and Lung Biology, School of Medicine, King's College, London, United Kingdom
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Irié-N'guessan G, Champy P, Kouakou-Siransy G, Koffi A, Kablan BJ, Leblais V. Tracheal relaxation of five Ivorian anti-asthmatic plants: role of epithelium and K⁺ channels in the effect of the aqueous-alcoholic extract of Dichrostachys cinerea root bark. JOURNAL OF ETHNOPHARMACOLOGY 2011; 138:432-438. [PMID: 21963567 DOI: 10.1016/j.jep.2011.09.016] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/20/2011] [Revised: 09/08/2011] [Accepted: 09/16/2011] [Indexed: 05/31/2023]
Abstract
ETHNOPHARMACOLOGICAL RELEVANCE Leaves of Boerhavia diffusa (Nyctaginaceae), Baphia nitida, Cassia occidentalis, Desmodium adscendens (Fabaceae), and root bark of Dichrostachys cinerea (Fabaceae) are used in Ivory Coast for the treatment of asthma. The aim of this study was to evaluate the potential airway relaxant activity of different extracts of these plants. MATERIALS AND METHODS Extracts of different polarities (H(2)O, EtOH/H(2)O, MeOH and CH(2)Cl(2)) were obtained from these five plants. Their ex vivo relaxant activity was tested in mice isolated trachea precontracted with carbachol (1 μM). RESULTS Cumulative concentrations of most extracts induced moderate to strong relaxation, the methanolic extracts being the most potent and the polar extracts the most active at the concentrations used, supporting the traditional use of these five plants as anti-asthmatic remedies. We further investigated the molecular and cellular mechanisms of the mouse trachea relaxant effect of the aqueous-alcoholic extract of Dichrostachys cinerea root bark, the most potent extract. Its effect was not modified in the presence of β-adrenoceptor antagonists (propranolol or ICI 118,551) or a PKA inhibitor (H89). By contrast, it was decreased after depolarization-induced precontraction (with 80 mM KCl), in the presence of some K(+) channels blockers [4-aminopyridine as voltage-dependent K(+) (K(v)) channel blocker and tetraethylammonium chloride as large conductance Ca(2+)-activated K(+) (BK(Ca)) channel blocker, but not with glibenclamide, an ATP-sensitive K(+) (K(ATP)) channel blocker] or after epithelium removal. CONCLUSIONS The mouse tracheal relaxant effect of Dichrostachys cinerea EtOH/H(2)O extract was independent of β(2)-adrenoceptors activation and cAMP/PKA pathway, but dependent on epithelium and K(+) channels, namely K(v) and BK(Ca) channels. Further investigation will be required to identify the component(s) responsible for this airways relaxant activity.
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Affiliation(s)
- Geneviève Irié-N'guessan
- Chimie des substances naturelles, CNRS UMR 8076 BioCIS, LabEx LERMIT, F-92296 Châtenay-Malabry, France.
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Castellano G, Affuso F, Conza PD, Fazio S. The GH/IGF-1 Axis and Heart Failure. Curr Cardiol Rev 2011; 5:203-15. [PMID: 20676279 PMCID: PMC2822143 DOI: 10.2174/157340309788970306] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/07/2008] [Revised: 01/22/2009] [Accepted: 01/23/2009] [Indexed: 01/24/2023] Open
Abstract
The growth hormone (GH)/insulin-like growth factor 1 (IGF-1) axis regulates cardiac growth, stimulates myocardial contractility and influences the vascular system. The GH/IGF-1 axis controls intrinsic cardiac contractility by enhancing the intracellular calcium availability and regulating expression of contractile proteins; stimulates cardiac growth, by increasing protein synthesis; modifies systemic vascular resistance, by activating the nitric oxide system and regulating non-endothelial-dependent actions. The relationship between the GH/IGF-1 axis and the cardiovascular system has been extensively demonstrated in numerous experimental studies and confirmed by the cardiac derangements secondary to both GH excess and deficiency. Several years ago, a clinical non-blinded study showed, in seven patients with idiopathic dilated cardiomyopathy and chronic heart failure (CHF), a significant improvement in cardiac function and structure after three months of treatment with recombinant GH plus standard therapy for heart failure. More recent studies, including a small double-blind placebo-controlled study on GH effects on exercise tolerance and cardiopulmonary performance, have shown that GH benefits patients with CHF secondary to both ischemic and idiopathic dilated cardiomyopathy. However, conflicting results emerge from other placebo-controlled trials. These discordant findings may be explained by the degree of CHF-associated GH resistance. In conclusion, we believe that more clinical and experimental studies are necessary to exactly understand the mechanisms that determine the variable sensitivity to GH and its positive effects in the failing heart.
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Affiliation(s)
- Graziella Castellano
- Department of Internal Medicine, School of Medicine, University of Naples "Federico II", Naples, Italy
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Ma H, Huang X, Li Q, Guan Y, Yuan F, Zhang Y. ATP-dependent potassium channels and mitochondrial permeability transition pores play roles in the cardioprotection of theaflavin in young rat. J Physiol Sci 2011; 61:337-42. [PMID: 21503789 PMCID: PMC10717146 DOI: 10.1007/s12576-011-0148-9] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2011] [Accepted: 03/30/2011] [Indexed: 01/30/2023]
Abstract
Previous studies have confirmed that tea polyphenols possess a broad spectrum of biological functions such as anti-oxidative, anti-bacterial, anti-tumor, anti-inflammatory, anti-viral and cardiovascular protection activities, as well as anti-cerebral ischemia-reperfusion injury properties. But the effect of tea polyphenols on ischemia/reperfusion heart has not been well elucidated. The aim of this study was to investigate the protective effect of theaflavin (TF1) and its underlying mechanism. Young male Sprague-Dawley (SD) rats were randomly divided into five groups: (1) the control group; (2) TF1 group; (3) glibenclamide + TF1 group; (4) 5-hydroxydecanoate (5-HD) + TF1 group; and (5) atractyloside + TF1 group. The Langendorff technique was used to record cardiac function in isolated rat heart before and after 30 min of global ischemia followed by 60 min of reperfusion. The parameters of cardiac function, including left ventricular developing pressure (LVDP), left ventricular end-diastolic pressure (LVEDP), maximal differentials of LVDP (± LVdP/dt (max)) and coronary flow (CF), were measured. The results showed: (1) compared with the control group, TF1 (10, 20, 40 μmol/l) displayed a better recovery of cardiac function after ischemia/reperfusion in a concentration-dependent manner. At 60 min of reperfusion, LVDP, ± LVdP/dt (max) and CF in the TF1 group were much higher than those in the control group, whereas left ventricular end-diastolic pressure (LVEDP) in the TF1 group was lower than that in the control group (P < 0.01). (2) Pretreatment with glibenclamide (10 μmol/l), a K(ATP) antagonist, completely abolished the cardioprotective effects of TF1 (20 μmol/l). Also, most of the effects of TF1 (20 μmol/l) on cardiac function after 60 min of reperfusion were reversed by 5-HD (100 μmol/l), a selective mitochondria K(ATP) antagonist. (3) Atractyloside (20 μmol/l), a mitochondrial permeability transition pore (mPTP) opener, administered at the beginning of 15 min of reperfusion completely abolished the cardioprotection of TF1 (20 μmol/l). The results indicate that TF1 protects the rat heart against ischemia/reperfusion injury through the opening of K(ATP) channels, particularly on the mitochondrial membrane, and inhibits mPTP opening.
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Affiliation(s)
- Huijie Ma
- Department of Physiology, Hebei Medical University, Shijiazhuang, 050017 China
| | - Xinli Huang
- Department of Pathophysiology, Hebei Medical University, Shijiazhuang, 050017 China
| | - Qian Li
- Department of Physiology, Hebei Medical University, Shijiazhuang, 050017 China
| | - Yue Guan
- Department of Physiology, Hebei Medical University, Shijiazhuang, 050017 China
| | - Fang Yuan
- Department of Physiology, Hebei Medical University, Shijiazhuang, 050017 China
| | - Yi Zhang
- Department of Physiology, Hebei Medical University, Shijiazhuang, 050017 China
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Diphosphate regulation of adenosine triphosphate sensitive potassium channel in human bladder smooth muscle cells. J Urol 2011; 186:736-44. [PMID: 21683406 DOI: 10.1016/j.juro.2011.03.153] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2010] [Indexed: 11/21/2022]
Abstract
PURPOSE To clarify the properties of adenosine triphosphate sensitive K+ channel in human detrusor smooth muscle we examined the effect of the representative nicotinic acid derivatives β-nicotinamide adenine dinucleotide, cyclic adenosine diphosphate ribose and nicotinic acid adenine dinucleotide phosphate (Sigma-Aldrich®) on human detrusor adenosine triphosphate sensitive K+ channels. MATERIALS AND METHODS Patch clamp procedures were done in human detrusor cells. Reverse transcriptase and real-time polymerase chain reaction were performed to clarify the subunit components of adenosine triphosphate sensitive K+ channels. RESULTS The K+ channel opener levcromakalim induced a long lasting outward current that was inhibited by glibenclamide (Sigma-Aldrich) under the whole cell configuration. The single channel study revealed that the unitary conductance of the adenosine triphosphate sensitive K+ channel in the human detrusor was 11 pS and nucleotide diphosphates increased its open probability. Applying β-nicotinamide adenine dinucleotide also activated the adenosine triphosphate sensitive K+ channel but applying cyclic adenosine diphosphate ribose or nicotinic acid adenine dinucleotide phosphate had little effect on channel activation. Molecular studies indicated that Kir6.1 and SUR2B were the predominant components of the adenosine triphosphate sensitive K+ channel in the human detrusor. CONCLUSIONS To our knowledge we report the first single channel study of the adenosine triphosphate sensitive K+ channel in the human detrusor. The properties of this channel, ie unitary conductance, adenosine triphosphate sensitivity and diphosphate activation, were consistent with those of other smooth muscle organs. β-Nicotinamide adenine dinucleotide has the potency to activate adenosine triphosphate sensitive K+ channels in the human detrusor. This channel likely has some role during ischemic conditions as well as physiological muscle motion leading to the activation of cell metabolism.
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Sun Y, Tang CS, Jin HF, Du JB. The vasorelaxing effect of hydrogen sulfide on isolated rat aortic rings versus pulmonary artery rings. Acta Pharmacol Sin 2011; 32:456-64. [PMID: 21468082 DOI: 10.1038/aps.2011.9] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
AIM To compare the vasorelaxing effects of hydrogen sulfide (H(2)S) on isolated aortic and pulmonary artery rings and to determine their action mechanisms. METHODS H(2)S-induced vasorelaxation of isolated rat aortic versus pulmonary artery rings under 95% O(2) and 5% CO(2) was analyzed. The expression of cystathinonine gamma-lyase (CSE), cystathionine beta synthase (CBS), 3-mercaptopyruvate sulfurtransferase (3MST), SUR2B and Kir6.1 was examined. RESULTS NaHS caused vasorelaxation of rat aortic and pulmonary artery rings in a dose-dependent manner. NaHS dilated aortic rings to a greater extent (16.4%, 38.4%, 64.1%, 84.3%, and 95.9% at concentrations of 50, 100, 200, 500, and 1000 μmol/L, respectively) than pulmonary artery rings (10.1%, 22.2%, 50.6%, 73.6%, and 84.6% at concentrations of 50, 100, 200, 500 and 1000 μmol/L, respectively). The EC(50) of the vasorelaxant effect for aortic rings was 152.17 μmol/L, whereas the EC(50) for pulmonary artery rings was 233.65 μmol/L. The vasorelaxing effect of H(2)S was markedly blocked b y cellular and mitochondrial membrane K(ATP) channel blockers in aortic rings (P<0.01). In contrast, only the cellular membrane K(ATP) channel blocker inhibited H(2)S-induced vasorelaxation in pulmonary artery rings. SUR2B mRNA and protein expression was higher in aortic rings than in pulmonary artery rings. Cystathinonine gamma-lyase (CSE) but not cystathionine beta synthase (CBS) expression in aortic rings was higher than in pulmonary artery rings. 3-Mercapto pyruvate sulfurtransferase (3MST) mRNA was lower in aortic rings than in pulmonary artery rings. CONCLUSION The vasorelaxing effect of H(2)S on isolated aortic rings was more pronounced than the effect on pulmonary artery rings at specific concentrations, which might be associated with increased expression of the K(ATP) channel subunit SUR2B.
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Denizalti M, Bozkurt TE, Akpulat U, Sahin-Erdemli I, Abacıoğlu N. The vasorelaxant effect of hydrogen sulfide is enhanced in streptozotocin-induced diabetic rats. Naunyn Schmiedebergs Arch Pharmacol 2011; 383:509-17. [PMID: 21394483 DOI: 10.1007/s00210-011-0601-6] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2010] [Accepted: 01/11/2011] [Indexed: 01/22/2023]
Abstract
Hydrogen sulfide (H₂S) is an endogenous gas which has potent relaxant effect in vascular and nonvascular smooth muscles. In the present study, we have investigated how streptozotocin (STZ)-induced diabetes affected the relaxant effect of H₂S in rat isolated thoracic aorta and mesenteric and pulmonary arteries. Diabetes was induced by IV injection of STZ (35 mg/kg). Insulin treatment was applied by using insulin implants. At the end of 4 and 12 weeks, the thoracic aorta and mesenteric and pulmonary arteries were isolated, and the relaxation responses to sodium hydrogen sulfide (NaHS), diazoxide, and acetylcholine were evaluated. The mRNA and protein levels of H₂S-synthesizing enzymes were also examined by RT-PCR and Western Blot. The relaxation response to NaHS in the arteries isolated from both 4 and 12 week-diabetic rats was increased when compared with that obtained from the control group. Glibenclamide inhibited the relaxation response to NaHS in the arteries isolated from either diabetic or non-diabetic group of rats. Concurrent treatment of insulin to STZ-injected rats prevented the potentiation of the relaxant effect of NaHS in the arteries. However, acetylcholine and diazoxide-induced relaxation responses were not altered in diabetic group of rats. The mRNA and protein levels of H₂S-synthesizing enzymes were also not altered in diabetic rats. STZ-induced experimental diabetes in rats resulted in the potentiation of the relaxation response to H₂S in vascular tissues. The potentiated relaxation to H₂S in diabetic arteries may play a role in vascular complications frequently seen in severe diabetes.
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Affiliation(s)
- Merve Denizalti
- Department of Pharmacology, Faculty of Pharmacy, Hacettepe University, 06100, Sihhiye, Ankara, Turkey
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Kawano T, Tanaka K, Yinhua, Eguchi S, Kawano H, Takahashi A, Nakaya Y, Oshita S. Effects of ketamine on nicorandil induced ATP-sensitive potassium channel activity in cell line derived from rat aortic smooth muscle. THE JOURNAL OF MEDICAL INVESTIGATION 2011; 57:237-44. [PMID: 20847523 DOI: 10.2152/jmi.57.237] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
PURPOSE Nicorandil opens adenosine triphosphate-sensitive potassium (K(ATP)) channels in the cardiovascular system and is being increasingly used for the treatment of angina pectoris. In the present study, we tested whether intravenous anesthetic agent ketamine affected nicorandil-induced native vascular K(ATP) channel activation. METHODS We used excised inside-out patch clamp configurations to investigate the direct effects of ketamine racemate and S-(+)-ketamine on the activities of K(ATP) channels in cultured rat aortic smooth muscle cells. Furthermore, we also investigated whether intracellular MgADP could modulate ketamine inhibition. RESULTS Nicorandil significantly activated K(ATP) channel activity, whereas this channel activity was completely blocked by glibenclamide, a specific K(ATP) channel blocker. Ketamine racemate inhibited the nicorandil induced K(ATP) channel activity (IC(50)=34±1 µM, n=14), but S-(+)-ketamine was less potent than ketamine racemate in blocking nicorandil induced K(ATP) channel activities (IC(50)=226±7 µM, n=10). Application of MgADP to the intracellular side of the channel was able to decrease the inhibitory potency of ketamine racemate on nicorandil induced K(ATP) channel activities. CONCLUSIONS Our results indicate that ketamine inhibits nicorandil induced K(ATP) channel activities in a dose dependent and stereoselective manner. Furthermore, increase of intracellular MgADP attenuates the inhibitory potency of ketamine racemate. J. Med. Invest. 57: 237-244, August, 2010.
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Affiliation(s)
- Takashi Kawano
- Department of Anesthesiology, Institute of Health Biosciences, the University of Tokushima Graduate School, Kuramoto, Tokushima, Japan
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The Protective Effect of Mitochondrial ATP-Sensitive K+ Channel Opener, Nicorandil, Combined With Na+/Ca2+ Exchange Blocker KB-R7943 on Myocardial Ischemia–Reperfusion Injury in Rat. Cell Biochem Biophys 2010; 60:219-24. [DOI: 10.1007/s12013-010-9142-8] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Targeting Hypertension With a New Adenosine Triphosphate–sensitive Potassium Channel Opener Iptakalim. J Cardiovasc Pharmacol 2010; 56:215-28. [DOI: 10.1097/fjc.0b013e3181e23e2b] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Noujaim SF, Stuckey JA, Ponce-Balbuena D, Ferrer-Villada T, López-Izquierdo A, Pandit S, Calvo CJ, Grzeda KR, Berenfeld O, Chapula JAS, Jalife J. Specific residues of the cytoplasmic domains of cardiac inward rectifier potassium channels are effective antifibrillatory targets. FASEB J 2010; 24:4302-12. [PMID: 20585026 DOI: 10.1096/fj.10-163246] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Atrial and ventricular tachyarrhythmias can be perpetuated by up-regulation of inward rectifier potassium channels. Thus, it may be beneficial to block inward rectifier channels under conditions in which their function becomes arrhythmogenic (e.g., inherited gain-of-function mutation channelopathies, ischemia, and chronic and vagally mediated atrial fibrillation). We hypothesize that the antimalarial quinoline chloroquine exerts potent antiarrhythmic effects by interacting with the cytoplasmic domains of Kir2.1 (I(K1)), Kir3.1 (I(KACh)), or Kir6.2 (I(KATP)) and reducing inward rectifier potassium currents. In isolated hearts of three different mammalian species, intracoronary chloroquine perfusion reduced fibrillatory frequency (atrial or ventricular), and effectively terminated the arrhythmia with resumption of sinus rhythm. In patch-clamp experiments chloroquine blocked I(K1), I(KACh), and I(KATP). Comparative molecular modeling and ligand docking of chloroquine in the intracellular domains of Kir2.1, Kir3.1, and Kir6.2 suggested that chloroquine blocks or reduces potassium flow by interacting with negatively charged amino acids facing the ion permeation vestibule of the channel in question. These results open a novel path toward discovering antiarrhythmic pharmacophores that target specific residues of the cytoplasmic domain of inward rectifier potassium channels.
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Affiliation(s)
- Sami F Noujaim
- Center for Arrhythmia Research, University of Michigan, Ann Arbor, MI 48108, USA
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Identification and characterization of a novel bacterial ATP-sensitive K+ channel. J Microbiol 2010; 48:325-30. [PMID: 20571950 DOI: 10.1007/s12275-010-9231-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2009] [Accepted: 12/22/2009] [Indexed: 10/19/2022]
Abstract
Five bacterial species that are most likely to have putative prokaryotic inward rectifier K(+) (Kir) channels were selected by in silico sequence homology and membrane topology analyses with respect to the number of transmembrane domains (TMs) and the presence of K(+) selectivity filter and/or ATP binding sites in reference to rabbit heart inward rectifier K(+) channel (Kir6.2). A dot blot assay with genomic DNAs when probed with whole rabbit Kir6.2 cDNA further supported the in silico analysis by exhibiting a stronger hybridization in species with putative Kir's compared to one without a Kir. Among them, Chromobacterium violaceum gave rise to a putative Kir channel gene, which was PCR-cloned into the bacterial expression vector pET30b(+), and its expression was induced in Escherichia coli and confirmed by gel purification and immunoblotting. On the other hand, this putative bacterial Kir channel was functionally expressed in Xenopus oocytes and its channel activity was measured electrophysiologically by using two electrode voltage clamping (TEVC). Results revealed a K(+) current with characteristics similar to those of the ATP-sensitive K(+) (K-ATP) channel. Collectively, cloning and functional characterization of bacterial ion channels could be greatly facilitated by combining the in silico analysis and heterologous expression in Xenopus oocytes.
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Jiang B, Tang G, Cao K, Wu L, Wang R. Molecular mechanism for H(2)S-induced activation of K(ATP) channels. Antioxid Redox Signal 2010; 12:1167-78. [PMID: 19769462 DOI: 10.1089/ars.2009.2894] [Citation(s) in RCA: 146] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Hydrogen sulfide (H(2)S) is an endogenous opener of K(ATP) channels in many different types of cells. However, the molecular mechanism for an interaction between H(2)S and K(ATP) channel proteins remains unclear. The whole-cell patch-clamp technique and mutagenesis approach were used to examine the effects of H(2)S on different K(ATP) channel subunits, rvKir6.1 and rvSUR1, heterologously expressed in HEK-293 cells. H(2)S stimulated coexpressed rvKir6.1/rvSUR1 K(ATP) channels, but had no effect on K(ATP) currents generated by rvKir6.1 expression alone. Intracellularly applied sulfhydryl alkylating agent (N-ethylmaleimide, NEM), oxidizing agent (chloramine T, CLT), and a disulfide bond-oxidizing enzyme (protein disulfide isomerase) did not alter H(2)S effects on this recombinant channels. CLT, but not NEM, inhibited basal rvKir6.1/rvSUR1 currents, and both abolished the stimulatory effects of H(2)S on K(ATP) currents, when applied extracellularly. After selective cysteine residues (C6S and C26S but not C1051S and C1057S) in the extracellular loop of rvSUR1 subunits were point-mutated, H(2)S lost its stimulatory effects on rvKir6.1/rvSUR1 currents. Our results demonstrate that H(2)S interacts with Cys6 and Cys26 residues of the extracellular N terminal of rvSUR1 subunit of K(ATP) channel complex. Direct chemical modification of rvSUR1 subunit protein constitutes a molecular mechanism for the activation of K(ATP) channels by H(2)S.
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Affiliation(s)
- Bo Jiang
- Department of Physiology & Pathophysiology, College of Medicine, Fudan University, Shanghai, PR China
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Wang Y, Hill JA. Electrophysiological remodeling in heart failure. J Mol Cell Cardiol 2010; 48:619-32. [PMID: 20096285 DOI: 10.1016/j.yjmcc.2010.01.009] [Citation(s) in RCA: 87] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/14/2008] [Revised: 01/11/2010] [Accepted: 01/12/2010] [Indexed: 11/25/2022]
Abstract
Heart failure affects nearly 6 million Americans, with a half-million new cases emerging each year. Whereas up to 50% of heart failure patients die of arrhythmia, the diverse mechanisms underlying heart failure-associated arrhythmia are poorly understood. As a consequence, effectiveness of antiarrhythmic pharmacotherapy remains elusive. Here, we review recent advances in our understanding of heart failure-associated molecular events impacting the electrical function of the myocardium. We approach this from an anatomical standpoint, summarizing recent insights gleaned from pre-clinical models and discussing their relevance to human heart failure.
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Affiliation(s)
- Yanggan Wang
- Department of Pediatrics, Emory University, Atlanta, GA, USA.
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Neuronal preconditioning by inhalational anesthetics: evidence for the role of plasmalemmal adenosine triphosphate-sensitive potassium channels. Anesthesiology 2009; 110:986-95. [PMID: 19352153 DOI: 10.1097/aln.0b013e31819dadc7] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
BACKGROUND Ischemic preconditioning is an important intrinsic mechanism for neuroprotection. Preconditioning can also be achieved by exposure of neurons to K+ channel-opening drugs that act on adenosine triphosphate-sensitive K+ (K(ATP)) channels. However, these agents do not readily cross the blood-brain barrier. Inhalational anesthetics which easily partition into brain have been shown to precondition various tissues. Here, the authors explore the neuronal preconditioning effect of modern inhalational anesthetics and investigate their effects on K(ATP) channels. METHODS Neuronal-glial cocultures were exposed to inhalational anesthetics in a preconditioning paradigm, followed by oxygen-glucose deprivation. Increased cell survival due to preconditioning was quantified with the 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide reduction test. Recombinant plasmalemmal K(ATP) channels of the main neuronal type (Kir6.2/SUR1) were expressed in HEK293 cells, and the effects of anesthetics were evaluated in whole cell patch clamp recordings. RESULTS Both sevoflurane and the noble gas xenon preconditioned neurons at clinically used concentrations. The effect of sevoflurane was independent of K(ATP) channel activation, whereas the effect of xenon required the opening of plasmalemmal K(ATP) channels. Recombinant K(ATP) channels were activated by xenon but inhibited by halogenated volatiles. Modulation of mitochondrial K-ATP channels did not affect the activity of K(ATP) channels, thus ruling out an indirect effect of volatiles via mitochondrial channels. CONCLUSIONS The preconditioning properties of halogenated volatiles cannot be explained by their effect on K(ATP) channels, whereas xenon preconditioning clearly involves the activation of these channels. Therefore, xenon might mimic the intrinsic mechanism of ischemic preconditioning most closely. This, together with its good safety profile, might suggest xenon as a viable neuroprotective agent in the clinical setting.
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Ploug KB, Sørensen MA, Strøbech L, Klaerke DA, Hay-Schmidt A, Sheykhzade M, Olesen J, Jansen-Olesen I. K ATP channels in pig and human intracranial arteries. Eur J Pharmacol 2008; 601:43-9. [PMID: 18996111 DOI: 10.1016/j.ejphar.2008.10.041] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2008] [Revised: 10/02/2008] [Accepted: 10/20/2008] [Indexed: 11/29/2022]
Abstract
Clinical trials suggest that synthetic ATP-sensitive K(+) (K(ATP)) channel openers may cause headache and migraine by dilating cerebral and meningeal arteries. We studied the mRNA expression profile of K(ATP) channel subunits in the pig and human middle meningeal artery (MMA) and in the pig middle cerebral artery (MCA). We determined the order of potency of four K(ATP) channel openers when applied to isolated pig MMA and MCA, and we examined the potential inhibitory effects of the Kir6.1 subunit specific K(ATP) channel blocker PNU-37883A on K(ATP) channel opener-induced relaxation of the isolated pig MMA and MCA. Using conventional RT-PCR, we detected the mRNA transcripts of the K(ATP) channel subunits Kir6.1 and SUR2B in all the examined pig and human intracranial arteries. Application of K(ATP) channel openers to isolated pig MMA and MCA in myographs caused a concentration-dependent vasodilatation with an order of potency that supports the presence of functional SUR2B K(ATP) channel subunits. 10(-7) M PNU-37883A significantly inhibited the in vitro dilatory responses of the potent K(ATP) channel opener P-1075 in both pig MMA and MCA. In conclusion, our combined mRNA expression and pharmacological studies indicate that Kir6.1/SUR2B is the major functional K(ATP) channel complex in the pig MMA and MCA, and mRNA expression studies suggest that the human MMA shares this K(ATP) channel subunit profile. Specific blocking of Kir6.1 or SUR2B K(ATP) channel subunits in large cerebral and meningeal arteries may be a future anti-migraine strategy.
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Affiliation(s)
- Kenneth Beri Ploug
- Department of Neurology and Danish Headache Center, Glostrup Research Institute, Glostrup Hospital, Faculty of Health Sciences, University of Copenhagen, Denmark.
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Breschi MC, Calderone V, Digiacomo M, Manganaro M, Martelli A, Minutolo F, Rapposelli S, Testai L, Tonelli F, Balsamo A. Spirocyclic Benzopyran-Based Derivatives as New Anti-ischemic Activators of Mitochondrial ATP-Sensitive Potassium Channel. J Med Chem 2008; 51:6945-54. [DOI: 10.1021/jm800956g] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Affiliation(s)
- Maria C. Breschi
- Dipartimento di Psichiatria, Neurobiologia, Farmacologia e Biotecnologie, Università di Pisa, Via Bonanno 6, 56126 Pisa, Italy, Dipartimento di Scienze Farmaceutiche, Università di Pisa, Via Bonanno 6, 56126 Pisa, Italy
| | - Vincenzo Calderone
- Dipartimento di Psichiatria, Neurobiologia, Farmacologia e Biotecnologie, Università di Pisa, Via Bonanno 6, 56126 Pisa, Italy, Dipartimento di Scienze Farmaceutiche, Università di Pisa, Via Bonanno 6, 56126 Pisa, Italy
| | - Maria Digiacomo
- Dipartimento di Psichiatria, Neurobiologia, Farmacologia e Biotecnologie, Università di Pisa, Via Bonanno 6, 56126 Pisa, Italy, Dipartimento di Scienze Farmaceutiche, Università di Pisa, Via Bonanno 6, 56126 Pisa, Italy
| | - Mariaelisa Manganaro
- Dipartimento di Psichiatria, Neurobiologia, Farmacologia e Biotecnologie, Università di Pisa, Via Bonanno 6, 56126 Pisa, Italy, Dipartimento di Scienze Farmaceutiche, Università di Pisa, Via Bonanno 6, 56126 Pisa, Italy
| | - Alma Martelli
- Dipartimento di Psichiatria, Neurobiologia, Farmacologia e Biotecnologie, Università di Pisa, Via Bonanno 6, 56126 Pisa, Italy, Dipartimento di Scienze Farmaceutiche, Università di Pisa, Via Bonanno 6, 56126 Pisa, Italy
| | - Filippo Minutolo
- Dipartimento di Psichiatria, Neurobiologia, Farmacologia e Biotecnologie, Università di Pisa, Via Bonanno 6, 56126 Pisa, Italy, Dipartimento di Scienze Farmaceutiche, Università di Pisa, Via Bonanno 6, 56126 Pisa, Italy
| | - Simona Rapposelli
- Dipartimento di Psichiatria, Neurobiologia, Farmacologia e Biotecnologie, Università di Pisa, Via Bonanno 6, 56126 Pisa, Italy, Dipartimento di Scienze Farmaceutiche, Università di Pisa, Via Bonanno 6, 56126 Pisa, Italy
| | - Lara Testai
- Dipartimento di Psichiatria, Neurobiologia, Farmacologia e Biotecnologie, Università di Pisa, Via Bonanno 6, 56126 Pisa, Italy, Dipartimento di Scienze Farmaceutiche, Università di Pisa, Via Bonanno 6, 56126 Pisa, Italy
| | - Federica Tonelli
- Dipartimento di Psichiatria, Neurobiologia, Farmacologia e Biotecnologie, Università di Pisa, Via Bonanno 6, 56126 Pisa, Italy, Dipartimento di Scienze Farmaceutiche, Università di Pisa, Via Bonanno 6, 56126 Pisa, Italy
| | - Aldo Balsamo
- Dipartimento di Psichiatria, Neurobiologia, Farmacologia e Biotecnologie, Università di Pisa, Via Bonanno 6, 56126 Pisa, Italy, Dipartimento di Scienze Farmaceutiche, Università di Pisa, Via Bonanno 6, 56126 Pisa, Italy
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Lybaert P, Vanbellinghen AM, Quertinmont E, Petein M, Meuris S, Lebrun P. KATP Channel Subunits Are Expressed in the Epididymal Epithelium in Several Mammalian Species1. Biol Reprod 2008; 79:253-61. [DOI: 10.1095/biolreprod.107.064659] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
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IMANI ALIREZA, FAGHIHI MAHDIEH, SADR SAYYEDSHAHABEDDIN, KESHAVARZ MANSOOR, NIARAKI SOMAYEHSADEGHI. Noradrenaline Reduces Ischemia-Induced Arrhythmia in Anesthetized Rats: Involvement of α1-Adrenoceptors and Mitochondrial KATPChannels. J Cardiovasc Electrophysiol 2008; 19:309-15. [DOI: 10.1111/j.1540-8167.2007.01031.x] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Hu D, Liu X, Wang Y, Chen S. Cyclovirobuxine D ameliorates acute myocardial ischemia by KATP channel opening, nitric oxide release and anti-thrombosis. Eur J Pharmacol 2007; 569:103-9. [PMID: 17555743 DOI: 10.1016/j.ejphar.2007.04.038] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2007] [Revised: 04/20/2007] [Accepted: 04/25/2007] [Indexed: 11/26/2022]
Abstract
Cyclovirobuxine D is an active compound extracted from Buxus microphylla, which has been used for treating acute myocardial ischemia in China. The present study was to investigate its mechanism on myocardial ischemia. Cyclovirobuxine D significantly increased cardiomyocytes viability injured by oxidation or hypoxia. It significantly reduced the infarct size induced by ligating the coronary artery in rats, and the effect was almost abolished by glibenclamide, a blocker of ATP sensitive potassium channel, but it was not influenced by cyclooxygenase-2 inhibitor celecoxib or estrogen receptor antagonist tamoxifen. In addition, cyclovirobuxine D significantly protected rat aorta endothelial cells against hypoxia and enhanced nitric oxide (NO) release from endothelial cells, which was inhibited by nitric oxide synthase (NOS) inhibitor N-nitro-L-arginine methyl ester (L-NAME). Furthermore, cyclovirobuxine D significantly decreased the weight of venous thrombus in rats. In conclusion, the action mechanism of cyclovirobuxine D on myocardial ischemia may be related with its cytoprotection, K(ATP) channel opening, NO generation stimulating and venous thrombosis inhibiting.
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MESH Headings
- Acute Disease
- Animals
- Animals, Newborn
- Celecoxib
- Cell Hypoxia/drug effects
- Cell Survival/drug effects
- Cells, Cultured
- Coronary Thrombosis/prevention & control
- Cyclooxygenase 2 Inhibitors/pharmacology
- Drugs, Chinese Herbal/pharmacology
- Drugs, Chinese Herbal/therapeutic use
- Endothelial Cells/cytology
- Endothelial Cells/drug effects
- Endothelial Cells/metabolism
- Estrogen Antagonists/pharmacology
- Glyburide/pharmacology
- Myocardial Ischemia/metabolism
- Myocardial Ischemia/physiopathology
- Myocardial Ischemia/prevention & control
- Myocytes, Cardiac/cytology
- Myocytes, Cardiac/drug effects
- Myocytes, Cardiac/metabolism
- NG-Nitroarginine Methyl Ester/pharmacology
- Nitric Oxide/metabolism
- Nitric Oxide Synthase/antagonists & inhibitors
- Nitric Oxide Synthase/metabolism
- Potassium Channel Blockers/pharmacology
- Potassium Channels, Inwardly Rectifying/agonists
- Potassium Channels, Inwardly Rectifying/antagonists & inhibitors
- Potassium Channels, Inwardly Rectifying/physiology
- Pyrazoles/pharmacology
- Rats
- Rats, Sprague-Dawley
- Sulfonamides/pharmacology
- Tamoxifen/pharmacology
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Affiliation(s)
- Die Hu
- Department of Molecular and Cellular Pharmacology, School of Pharmaceutical Sciences, Peking University, Beijing 100083, China
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Jewsbury S, Baker PN, Wareing M. Relaxation of human placental arteries and veins by ATP-sensitive potassium channel openers. Eur J Clin Invest 2007; 37:65-72. [PMID: 17181569 DOI: 10.1111/j.1365-2362.2007.01749.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
BACKGROUND Adenosine triphosphate (ATP)-sensitive potassium channels (K(ATP)) are important modulators of vascular tone. Preliminary data from our laboratory suggests that K(ATP) channels are expressed in the fetoplacental vasculature where addition of pinacidil, a specific K(ATP) opener, promotes relaxation. We aimed to assess the effects of KRN2391 and KRN4884 on the fetoplacental vasculature, which are putative K(ATP) channel openers. MATERIALS AND METHODS Functional activity of K(ATP) channels was assessed in chorionic plate arteries and veins using wire myography. Cromakalim-, KRN2391- and KRN4884-induced relaxations were assessed in the presence and absence of agonist-induced pretone. Cromakalim, an established K(ATP) channel opener, acted as control. RESULTS KRN2391 evoked significantly greater relaxation of chorionic plate arteries and veins than either KRN4884 or cromakalim. KRN2391-induced relaxation of precontracted arteries and veins was reduced in the presence of inhibitors of the nitric oxide pathway (L-NNA or LY83583). With KRN4884, there was no contribution of nitric oxide to the induced relaxation. CONCLUSIONS We conclude that K(ATP) channels play an important role in controlling placental vascular tone. KRN2391 induces relaxation of human placental blood vessels by activation of K(ATP) channels and via activation of nitric oxide-dependent pathways.
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Affiliation(s)
- S Jewsbury
- The University of Manchester, St. Mary's Hospital, Hathersage Road, Manchester M13 0JH, UK
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Polat B, Tufan H, Danisman N. Vasorelaxant effect of levcromakalim on isolated umbilical arteries of preeclamptic women. Eur J Obstet Gynecol Reprod Biol 2006; 134:169-73. [PMID: 17123695 DOI: 10.1016/j.ejogrb.2006.09.015] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2005] [Revised: 06/04/2006] [Accepted: 09/19/2006] [Indexed: 11/17/2022]
Abstract
OBJECTIVE Potassium channel openers are revealed to be a new type of antihypertensive drug. We aimed to clarify the effects of levcromakalim, an ATP-sensitive potassium channel opener, on human isolated umbilical artery (UA) and to compare them with those of nifedipine and magnesium sulphate, which are currently used in the treatment of preeclampsia (PE). STUDY DESIGN A total of 52 umbilical arteries, isolated immediately after delivery from 27 healthy and 25 preeclamptic pregnant women, were placed into 10-ml organ baths filled with Kreb's solution at physiological pH and temperature. The concentration-dependent relaxations in response to levcromakalim, nifedipine and magnesium sulphate were compared in vessels precontracted with serotonin (1 micromol/l). RESULTS The maximal relative relaxation responses (E(max), expressed as percentage of serotonin-induced precontraction) to magnesium sulphate, nifedipine and levcromakalim in umbilical arteries were identical in the healthy (85.06+/-3.31, 84.80+/-3.01 and 80.37+/-5.32%, respectively) and preeclamptic (77.20+/-5.30, 83.36+/-2.37 and 79.13+/-4.30%, respectively) groups. CONCLUSION Levcromakalim has a vasodilatory effect on the umbilical artery like magnesium sulphate and nifedipine, and serves as an antihypertensive potential that might be used in the treatment of preeclampsia. However, further experimental and clinical studies are needed to propose that ATP-sensitive potassium channel openers are beneficial drugs in cases of clinical preeclampsia.
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Affiliation(s)
- Belgin Polat
- Zekai Tahir Burak Maternity Hospital, Perinatalogy, Ankara, Turkey.
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Wang H, Tang Y, Zhang YL. Hypoxic pulmonary hypertension (HPH) and iptakalim, a novel ATP-sensitive potassium channel opener targeting smaller arteries in hypertension. ACTA ACUST UNITED AC 2006; 23:293-316. [PMID: 16614730 DOI: 10.1111/j.1527-3466.2005.tb00174.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Hypoxic pulmonary hypertension (HPH) is a serious and potentially devastating chronic disorder of the pulmonary circulation. Attempts to use drugs in the therapy of hypoxic pulmonary hypertension indicated the importance of prevention or reduction of vasoconstriction as well as of the reversal of remodeling within the cardiovascular system. Iptakalim (2,3-dimethyl-N-(1-methylethyl)-2-butylamine), a novel ATP-sensitive potassium channel opener, has the desired effects on hypoxic pulmonary arteries. Iptakalim decreases the elevated mean pressure in pulmonary arteries, and attenuates remodeling in the right ventricle, pulmonary arteries and airways. Moreover, iptakalim has selective antihypertensive effects: it significantly lowers arterial pressure in hypertensive animals, but has little if any effect in normotensive animals. In HPH iptakalim has selective effects on smaller arteries. Long-term iptakalim therapy decreases expression of sulfonylurea receptor 2 and of mRNA of inwardly rectifying potassium channel in smaller arteries of spontaneously hypertensive rats. Iptakalim inhibits the effects of endothelin-1, reduces the intracellular calcium concentration and inhibits the cell cycle in smooth muscle cells of pulmonary arteries. There is no evidence for the development of tolerance to the long-lasting antihypertensive action of iptakalim. At therapeutic doses iptakalim has no effects on the central nervous, respiratory, digestive, or endocrine systems. It has a broad therapeutic range, so that it can be safely used in the therapy of HPH.
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Affiliation(s)
- Hai Wang
- Department of Cardiovascular Pharmacology, Beijing Institute of Pharmacology and Toxicology, 27 Taiping Road, Beijing 100850, Peoples' Republic of China.
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