1
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Gerzen OP, Votinova VO, Potoskueva IK, Tzybina AE, Nikitina LV. Direct Effects of Toxic Divalent Cations on Contractile Proteins with Implications for the Heart: Unraveling Mechanisms of Dysfunction. Int J Mol Sci 2023; 24:10579. [PMID: 37445756 DOI: 10.3390/ijms241310579] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2023] [Revised: 06/19/2023] [Accepted: 06/22/2023] [Indexed: 07/15/2023] Open
Abstract
The binding of calcium and magnesium ions to proteins is crucial for regulating heart contraction. However, other divalent cations, including xenobiotics, can accumulate in the myocardium and enter cardiomyocytes, where they can bind to proteins. In this article, we summarized the impact of these cations on myosin ATPase activity and EF-hand proteins, with special attention given to toxic cations. Optimal binding to EF-hand proteins occurs at an ionic radius close to that of Mg2+ and Ca2+. In skeletal Troponin C, Cd2+, Sr2+, Pb2+, Mn2+, Co2+, Ni2+, Ba2+, Mg2+, Zn2+, and trivalent lanthanides can substitute for Ca2+. As myosin ATPase is not a specific MgATPase, Ca2+, Fe2+, Mn2+, Ni2+, and Sr2+ could support myosin ATPase activity. On the other hand, Zn2+ and Cu2 significantly inhibit ATPase activity. The affinity to various divalent cations depends on certain proteins or their isoforms and can alter with amino acid substitution and post-translational modification. Cardiac EF-hand proteins and the myosin ATP-binding pocket are potential molecular targets for toxic cations, which could significantly alter the mechanical characteristics of the heart muscle at the molecular level.
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Affiliation(s)
- Oksana P Gerzen
- Institute of Immunology and Physiology of the Ural Branch of the Russian Academy of Sciences, 620049 Ekaterinburg, Russia
| | - Veronika O Votinova
- Institute of Immunology and Physiology of the Ural Branch of the Russian Academy of Sciences, 620049 Ekaterinburg, Russia
| | - Iulia K Potoskueva
- Institute of Immunology and Physiology of the Ural Branch of the Russian Academy of Sciences, 620049 Ekaterinburg, Russia
| | - Alyona E Tzybina
- Institute of Immunology and Physiology of the Ural Branch of the Russian Academy of Sciences, 620049 Ekaterinburg, Russia
| | - Larisa V Nikitina
- Institute of Immunology and Physiology of the Ural Branch of the Russian Academy of Sciences, 620049 Ekaterinburg, Russia
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2
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Pustovit KB, Samoilova DV, Abramochkin DV, Filatova TS, Kuzmin VS. α1-adrenergic receptors accompanied by GATA4 expression are related to proarrhythmic conduction and automaticity in rat interatrial septum. J Physiol Biochem 2022; 78:793-805. [PMID: 35802254 DOI: 10.1007/s13105-022-00902-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2021] [Accepted: 05/19/2022] [Indexed: 11/25/2022]
Abstract
The development of interatrial septum (IAS) is a complicated process, which continues during postnatal life. The hypertrophic signals in developing heart are mediated among others by α-adrenergic pathways. These facts suggest the presence of specific electrophysiological features in developing IAS. This study was aimed to investigate the electrical activity in the tissue preparations of IAS from rat heart in normal conditions and under stimulation of adrenoreceptors. Intracellular recording of electrical activity revealed less negative level of resting membrane potential in IAS if compared to myocardium of left atrium. In normal conditions, non-paced IAS preparations were quiescent, but noradrenaline (10-5 M) and phenylephrine (10-5 M) induced spontaneous action potentials, which could be abolished by α1-blocker prazosin (10-5 M), but not β1-blocker atenolol (10-5 M). Optical mapping showed drastic phenylephrine-induced slowing of conduction in adult rat IAS. The α1-dependent ectopic automaticity of IAS myocardium might be explained by immunohistochemical data indicating the presence of transcription factor GATA4 and abundant α1A-adrenoreceptors in myocytes from adult rat IAS. An elevated sensitivity to adrenergic stimulation due to involvement of α1-adrenergic pathways may underlie increased proarrhythmic potential of adult IAS at least in rats.
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Affiliation(s)
- Ksenia B Pustovit
- Department of Human and Animal Physiology, Lomonosov Moscow State University, Leninskiye Gory, 1, 12, Moscow, Russia
| | - Daria V Samoilova
- N. N. Blokhin National Medical Research Centre of Oncology, Kashirskoye sh., 24, Moscow, Russia
| | - Denis V Abramochkin
- Department of Human and Animal Physiology, Lomonosov Moscow State University, Leninskiye Gory, 1, 12, Moscow, Russia.
| | - Tatiana S Filatova
- Department of Human and Animal Physiology, Lomonosov Moscow State University, Leninskiye Gory, 1, 12, Moscow, Russia.,Laboratory of Cardiac Electrophysiology, National Medical Research Center for Cardiology, 3rd Cherepkovskaya, 15a, Moscow, Russia.,Department of Physiology, Pirogov Russian National Research Medical University, Ostrovityanova str., 1, Moscow, Russia
| | - Vladislav S Kuzmin
- Department of Human and Animal Physiology, Lomonosov Moscow State University, Leninskiye Gory, 1, 12, Moscow, Russia
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3
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Okada D, Okamoto Y, Io T, Oka M, Kobayashi D, Ito S, Yamada R, Ishii K, Ono K. Comparative Study of Transcriptome in the Hearts Isolated from Mice, Rats, and Humans. Biomolecules 2022; 12:biom12060859. [PMID: 35740984 PMCID: PMC9221511 DOI: 10.3390/biom12060859] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2022] [Revised: 06/16/2022] [Accepted: 06/17/2022] [Indexed: 01/27/2023] Open
Abstract
The heart is a significant organ in mammalian life, and the heartbeat mechanism has been an essential focus of science. However, few studies have focused on species differences. Accordingly, challenges remain in studying genes that have universal functions across species and genes that determine species differences. Here, we analyzed transcriptome data in mouse, rat, and human atria, ventricles, and sinoatrial nodes (SA) obtained from different platforms and compared them by calculating specificity measure (SPM) values in consideration of species differences. Among the three heart regions, the species differences in SA were the greatest, and we searched for genes that determined the essential characteristics of SA, which was SHOX2 in our criteria. The SPM value of SHOX2 was prominently high across species. Similarly, by calculating SPM values, we identified 3 atrial-specific, 11 ventricular-specific, and 17 SA-specific markers. Ontology analysis identified 70 cardiac region- and species-specific ontologies. These results suggest that reanalyzing existing data by calculating SPM values may identify novel tissue-specific genes and species-dependent gene expression. This study identified the importance of SHOX2 as an SA-specific transcription factor, a novel cardiac regional marker, and species-dependent ontologies.
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Affiliation(s)
- Daigo Okada
- Center for Genomic Medicine, Graduate School of Medicine, Kyoto University, Shogoinkawahara-cho, Kyoto 606-8507, Japan; (D.O.); (R.Y.)
| | - Yosuke Okamoto
- Department of Cell Physiology, Akita Graduate School of Medicine, Hondo, Akita 010-8543, Japan; (D.K.); (S.I.); (K.O.)
- Correspondence:
| | - Toshiro Io
- Research Department, Ono Pharmaceutical Co., Ltd., Kyutaromachi, Osaka 618-8585, Japan; (T.I.); (M.O.)
| | - Miho Oka
- Research Department, Ono Pharmaceutical Co., Ltd., Kyutaromachi, Osaka 618-8585, Japan; (T.I.); (M.O.)
| | - Daiki Kobayashi
- Department of Cell Physiology, Akita Graduate School of Medicine, Hondo, Akita 010-8543, Japan; (D.K.); (S.I.); (K.O.)
| | - Suzuka Ito
- Department of Cell Physiology, Akita Graduate School of Medicine, Hondo, Akita 010-8543, Japan; (D.K.); (S.I.); (K.O.)
| | - Ryo Yamada
- Center for Genomic Medicine, Graduate School of Medicine, Kyoto University, Shogoinkawahara-cho, Kyoto 606-8507, Japan; (D.O.); (R.Y.)
| | - Kuniaki Ishii
- Department of Pharmacology, Faculty of medicine, Yamagata University, Iida-Nishi, Yamagata 990-9585, Japan;
| | - Kyoichi Ono
- Department of Cell Physiology, Akita Graduate School of Medicine, Hondo, Akita 010-8543, Japan; (D.K.); (S.I.); (K.O.)
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4
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Preferential Expression of Ca2+-Stimulable Adenylyl Cyclase III in the Supraventricular Area, Including Arrhythmogenic Pulmonary Vein of the Rat Heart. Biomolecules 2022; 12:biom12050724. [PMID: 35625651 PMCID: PMC9138642 DOI: 10.3390/biom12050724] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2022] [Revised: 05/16/2022] [Accepted: 05/19/2022] [Indexed: 12/10/2022] Open
Abstract
Ectopic excitability in pulmonary veins (PVs) is the major cause of atrial fibrillation. We previously reported that the inositol trisphosphate receptor in rat PV cardiomyocytes cooperates with the Na+-Ca2+ exchanger to provoke ectopic automaticity in response to norepinephrine. Here, we focused on adenylyl cyclase (AC) as another effector of norepinephrine stimulation. RT-PCR, immunohistochemistry, and Western blotting revealed that the abundant expression of Ca2+-stimulable AC3 was restricted to the supraventricular area, including the PVs. All the other AC isotypes hardly displayed any region-specific expressions. Immunostaining of isolated cardiomyocytes showed an enriched expression of AC3 along the t-tubules in PV myocytes. The cAMP-dependent response of L-type Ca2+ currents in the PV and LA cells is strengthened by the 0.1 mM intracellular Ca2+ condition, unlike in the ventricular cells. The norepinephrine-induced automaticity of PV cardiomyocytes was reversibly suppressed by 100 µM SQ22536, an adenine-like AC inhibitor. These findings suggest that the specific expression of AC3 along t-tubules may contribute to arrhythmogenic automaticity in rat PV cardiomyocytes.
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5
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Tsumoto K, Kurata Y. Bifurcations and Proarrhythmic Behaviors in Cardiac Electrical Excitations. Biomolecules 2022; 12:biom12030459. [PMID: 35327651 PMCID: PMC8946197 DOI: 10.3390/biom12030459] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2022] [Revised: 03/09/2022] [Accepted: 03/14/2022] [Indexed: 12/23/2022] Open
Abstract
The heart is a hierarchical dynamic system consisting of molecules, cells, and tissues, and acts as a pump for blood circulation. The pumping function depends critically on the preceding electrical activity, and disturbances in the pattern of excitation propagation lead to cardiac arrhythmia and pump failure. Excitation phenomena in cardiomyocytes have been modeled as a nonlinear dynamical system. Because of the nonlinearity of excitation phenomena, the system dynamics could be complex, and various analyses have been performed to understand the complex dynamics. Understanding the mechanisms underlying proarrhythmic responses in the heart is crucial for developing new ways to prevent and control cardiac arrhythmias and resulting contractile dysfunction. When the heart changes to a pathological state over time, the action potential (AP) in cardiomyocytes may also change to a different state in shape and duration, often undergoing a qualitative change in behavior. Such a dynamic change is called bifurcation. In this review, we first summarize the contribution of ion channels and transporters to AP formation and our knowledge of ion-transport molecules, then briefly describe bifurcation theory for nonlinear dynamical systems, and finally detail its recent progress, focusing on the research that attempts to understand the developing mechanisms of abnormal excitations in cardiomyocytes from the perspective of bifurcation phenomena.
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6
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Automatic Activity Arising in Cardiac Muscle Sleeves of the Pulmonary Vein. Biomolecules 2021; 12:biom12010023. [PMID: 35053171 PMCID: PMC8773798 DOI: 10.3390/biom12010023] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2021] [Revised: 12/21/2021] [Accepted: 12/22/2021] [Indexed: 02/06/2023] Open
Abstract
Ectopic activity in the pulmonary vein cardiac muscle sleeves can both induce and maintain human atrial fibrillation. A central issue in any study of the pulmonary veins is their difference from the left atrial cardiac muscle. Here, we attempt to summarize the physiological phenomena underlying the occurrence of ectopic electrical activity in animal pulmonary veins. We emphasize that the activation of multiple signaling pathways influencing not only myocyte electrophysiology but also the means of excitation–contraction coupling may be required for the initiation of triggered or automatic activity. We also gather information regarding not only the large-scale structure of cardiac muscle sleeves but also recent studies suggesting that cellular heterogeneity may contribute to the generation of arrythmogenic phenomena and to the distinction between pulmonary vein and left atrial heart muscle.
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7
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Wang X, Pierre V, Senapati S, Park PSH, Senyo SE. Microenvironment Stiffness Amplifies Post-ischemia Heart Regeneration in Response to Exogenous Extracellular Matrix Proteins in Neonatal Mice. Front Cardiovasc Med 2021; 8:773978. [PMID: 34805326 PMCID: PMC8602555 DOI: 10.3389/fcvm.2021.773978] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2021] [Accepted: 10/14/2021] [Indexed: 11/13/2022] Open
Abstract
The cardiogenesis of the fetal heart is absent in juveniles and adults. Cross-transplantation of decellularized extracellular matrix (dECM) can stimulate regeneration in myocardial infarct (MI) models. We have previously shown that dECM and tissue stiffness have cooperative regulation of heart regeneration in transiently regenerative day 1 neonatal mice. To investigate underlying mechanisms of mechano-signaling and dECM, we pharmacologically altered heart stiffness and administered dECM hydrogels in non-regenerative mice after MI. The dECM combined with softening exhibits preserved cardiac function, LV geometry, increased cardiomyocyte mitosis and lowered fibrosis while stiffening further aggravated ischemic damage. Transcriptome analysis identified a protein in cardiomyocytes, CLCA2, confirmed to be upregulated after MI and downregulated by dECM in a mechanosensitive manner. Synthetic knock-down of CLCA2 expression induced mitosis in primary rat cardiomyocytes in the dish. Together, our results indicate that therapeutic efficacy of extracellular molecules for heart regeneration can be modulated by heart microenvironment stiffness in vivo.
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Affiliation(s)
- Xinming Wang
- Department of Biomedical Engineering, Case School of Engineering, Case Western Reserve University, Cleveland, OH, United States
| | - Valinteshley Pierre
- Department of Biomedical Engineering, Case School of Engineering, Case Western Reserve University, Cleveland, OH, United States
| | - Subhadip Senapati
- Department of Ophthalmology and Visual Sciences, School of Medicine, Case Western Reserve University, Cleveland, OH, United States
| | - Paul S.-H. Park
- Department of Ophthalmology and Visual Sciences, School of Medicine, Case Western Reserve University, Cleveland, OH, United States
| | - Samuel E. Senyo
- Department of Biomedical Engineering, Case School of Engineering, Case Western Reserve University, Cleveland, OH, United States
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8
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Kuzmin VS, Ivanova AD, Potekhina VM, Samoilova DV, Ushenin KS, Shvetsova AA, Petrov AM. The susceptibility of the rat pulmonary and caval vein myocardium to the catecholamine-induced ectopy changes oppositely in postnatal development. J Physiol 2021; 599:2803-2821. [PMID: 33823063 DOI: 10.1113/jp280485] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2020] [Accepted: 03/30/2021] [Indexed: 11/08/2022] Open
Abstract
KEY POINTS The developmental changes of the caval (SVC) and pulmonary vein (PV) myocardium electrophysiology are traced throughout postnatal ontogenesis. The myocardium in SVC as well as in PV demonstrate age-dependent differences in the ability to maintain resting membrane potential, to manifest automaticity in a form of ectopic action potentials in basal condition and in responses to the adrenergic stimulation. Electrophysiological characteristics of two distinct types of thoracic vein myocardium change in an opposite manner during early postnatal ontogenesis with increased proarrhythmicity of pulmonary and decreased automaticity in caval veins. Predisposition of PV cardiac tissue to proarrhythmycity develops during ontogenesis in time correlation with the establishment of sympathetic innervation of the tissue. The electrophysiological properties of caval vein cardiac tissue shift from a pacemaker-like phenotype to atrial phenotype in accompaniment with sympathetic nerve growth and adrenergic receptor expression changes. ABSTRACT The thoracic vein myocardium is considered as a main source for atrial fibrillation initiation due to its high susceptibility to ectopic activity. The mechanism by which and when pulmonary (PV) and superior vena cava (SVC) became proarrhythmic during postnatal ontogenesis is still unknown. In this study, we traced postnatal changes of electrophysiology in a correlation with the sympathetic innervation and adrenergic receptor distribution to reveal developmental differences in proarrhythmicity occurrence in PV and SVC myocardium. A standard microelectrode technique was used to assess the changes in ability to maintain resting membrane potential (RMP), generate spontaneous action potentials (SAP) and adrenergically induced ectopy in multicellular SVC and PV preparations of rats of different postnatal ages. Immunofluorescence imaging was used to trace postnatal changes in sympathetic innervation, β1- and α1A-adrenergic receptor (AR) distribution. We revealed that the ability to generate SAP and susceptibility to adrenergic stimulation changes during postnatal ontogenesis in an opposite manner in PV and SVC myocardium. While SAP occurrence decreases with age in SVC myocardium, it significantly increases in PV cardiac tissue. PV myocardium starts to demonstrate RMP instability and proarrhythmic activity from the 14th day of postnatal life which correlates with the appearance of the sympathetic innervation of the thoracic veins. In addition, postnatal attenuation of SVC myocardium automaticity occurs concomitantly with sympathetic innervation establishment and increase in β1-ARs, but not α1A-AR levels. Our results support the contention that SVC and PV myocardium electrophysiology change during postnatal development, resulting in higher PV proarrhythmicity in adults.
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Affiliation(s)
- Vlad S Kuzmin
- Department of Human and Animal Physiology, Biological Faculty, Lomonosov Moscow State University, Leninskie gory 1, building 12, Moscow, 119991, Russia.,Pirogov Russian National Research Medical University (RNRMU), Ostrovitjanova 1, Moscow, 117997, Russia.,Laboratory of Cardiac Electrophysiology, National Medical Research Cardiological Complex (NMRCC), Institute of Experimental Cardiology, Moscow, Russia
| | - Alexandra D Ivanova
- Department of Human and Animal Physiology, Biological Faculty, Lomonosov Moscow State University, Leninskie gory 1, building 12, Moscow, 119991, Russia
| | - Viktoria M Potekhina
- Department of Human and Animal Physiology, Biological Faculty, Lomonosov Moscow State University, Leninskie gory 1, building 12, Moscow, 119991, Russia
| | - Daria V Samoilova
- N. N. Blokhin National Medical Research Centre of Oncology, Moscow, Russia
| | | | - Anastasia A Shvetsova
- Department of Human and Animal Physiology, Biological Faculty, Lomonosov Moscow State University, Leninskie gory 1, building 12, Moscow, 119991, Russia
| | - Alexey M Petrov
- Institute of Neuroscience, Kazan State Medial University, Butlerova st. 49, Kazan, 420012, Russia.,Laboratory of Biophysics of Synaptic Processes, Kazan Institute of Biochemistry and Biophysics, Federal Research Center 'Kazan Scientific Center of RAS', P. O. Box 30, Lobachevsky Str., 2/31, Kazan, 420111, Russia
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9
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Varró A, Tomek J, Nagy N, Virág L, Passini E, Rodriguez B, Baczkó I. Cardiac transmembrane ion channels and action potentials: cellular physiology and arrhythmogenic behavior. Physiol Rev 2020; 101:1083-1176. [PMID: 33118864 DOI: 10.1152/physrev.00024.2019] [Citation(s) in RCA: 72] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Cardiac arrhythmias are among the leading causes of mortality. They often arise from alterations in the electrophysiological properties of cardiac cells and their underlying ionic mechanisms. It is therefore critical to further unravel the pathophysiology of the ionic basis of human cardiac electrophysiology in health and disease. In the first part of this review, current knowledge on the differences in ion channel expression and properties of the ionic processes that determine the morphology and properties of cardiac action potentials and calcium dynamics from cardiomyocytes in different regions of the heart are described. Then the cellular mechanisms promoting arrhythmias in congenital or acquired conditions of ion channel function (electrical remodeling) are discussed. The focus is on human-relevant findings obtained with clinical, experimental, and computational studies, given that interspecies differences make the extrapolation from animal experiments to human clinical settings difficult. Deepening the understanding of the diverse pathophysiology of human cellular electrophysiology will help in developing novel and effective antiarrhythmic strategies for specific subpopulations and disease conditions.
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Affiliation(s)
- András Varró
- Department of Pharmacology and Pharmacotherapy, Faculty of Medicine, University of Szeged, Szeged, Hungary.,MTA-SZTE Cardiovascular Pharmacology Research Group, Hungarian Academy of Sciences, Szeged, Hungary
| | - Jakub Tomek
- Department of Computer Science, British Heart Foundation Centre of Research Excellence, University of Oxford, Oxford, United Kingdom
| | - Norbert Nagy
- Department of Pharmacology and Pharmacotherapy, Faculty of Medicine, University of Szeged, Szeged, Hungary.,MTA-SZTE Cardiovascular Pharmacology Research Group, Hungarian Academy of Sciences, Szeged, Hungary
| | - László Virág
- Department of Pharmacology and Pharmacotherapy, Faculty of Medicine, University of Szeged, Szeged, Hungary
| | - Elisa Passini
- Department of Computer Science, British Heart Foundation Centre of Research Excellence, University of Oxford, Oxford, United Kingdom
| | - Blanca Rodriguez
- Department of Computer Science, British Heart Foundation Centre of Research Excellence, University of Oxford, Oxford, United Kingdom
| | - István Baczkó
- Department of Pharmacology and Pharmacotherapy, Faculty of Medicine, University of Szeged, Szeged, Hungary
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10
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Egorov YV, Rosenshtraukh LV, Glukhov AV. Arrhythmogenic Interaction Between Sympathetic Tone and Mechanical Stretch in Rat Pulmonary Vein Myocardium. Front Physiol 2020; 11:237. [PMID: 32273849 PMCID: PMC7113560 DOI: 10.3389/fphys.2020.00237] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2019] [Accepted: 03/02/2020] [Indexed: 11/21/2022] Open
Abstract
Rapid firing from pulmonary veins (PVs) frequently initiates atrial fibrillation, which is a common comorbidity associated with hypertension, heart failure, and valvular disease, i.e., conditions that pathologically increase cardiomyocyte stretch. Autonomic tone plays a crucial role in PV arrhythmogenesis, while its interplay with myocardium stretch remains uncertain. Two-microelectrode technique was used to characterize electrophysiological response of Wistar rat PV to adrenaline at baseline and under mild (150 mg of applied weight that corresponds to a pulmonary venous pressure of 1 mmHg) and moderate (10 g, ∼26 mmHg) stretch. Low concentrations of adrenaline (25–100 nmol/L) depolarized the resting membrane potential selectively within distal PV (by 26 ± 2 mV at baseline, by 18 ± 1 mV at 150 mg, P < 0.001, and by 5.9 ± 1.1 mV at 10 g, P < 0.01) suppressing action potential amplitude and resulting in intra-PV conduction dissociation and rare episodes of spontaneous activity (arrhythmia index of 0.4 ± 0.2, NS vs. no activity at baseline). In contrast, 1–10 μmol/L of adrenaline recovered intra-PV propagation. While mild stretch did not affect PV electrophysiology at baseline, moderate stretch depolarized the resting potential within distal PV (-56 ± 2 mV vs. -82 ± 1 mV at baseline, P < 0.01), facilitated the triggering of rapid PV firing by adrenaline (arrhythmia index: 4.4 ± 0.2 vs. 1.3 ± 0.4 in unstretched, P < 0.001, and 1.7 ± 0.8 in mildly stretched preparations, P < 0.005, at 10 μmol/L adrenaline) and induced frequent episodes of potentially arrhythmogenic atrial “echo” extra beats. Our findings demonstrate complex interactions between the sympathetic tone and mechanical stretch in the development of arrhythmogenic activity within PVs that may impact an increased atrial fibrillation vulnerability in patients with elevated blood pressure.
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Affiliation(s)
- Yuriy V Egorov
- Laboratory of Heart Electrophysiology, Russian Cardiology Research Centre, Institute of Experimental Cardiology, Moscow, Russia
| | - Leonid V Rosenshtraukh
- Laboratory of Heart Electrophysiology, Russian Cardiology Research Centre, Institute of Experimental Cardiology, Moscow, Russia
| | - Alexey V Glukhov
- Department of Medicine, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, WI, United States
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11
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Bredeloux P, Findlay I, Pasqualin C, Hocini M, Bernus O, Maupoil V. Selective inhibition of electrical conduction within the pulmonary veins by α1-adrenergic receptors activation in the Rat. Sci Rep 2020; 10:5390. [PMID: 32214185 PMCID: PMC7096464 DOI: 10.1038/s41598-020-62349-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2019] [Accepted: 03/11/2020] [Indexed: 11/25/2022] Open
Abstract
Pulmonary veins (PV) are involved in the pathophysiology of paroxysmal atrial fibrillation. In the rat, left atrium (LA) and PV cardiomyocytes have different reactions to α1-adrenergic receptor activation. In freely beating atria-PV preparations, we found that electrical field potential (EFP) originated from the sino-atrial node propagated through the LA and the PV. The α1-adrenergic receptor agonist cirazoline induced a progressive loss of EFP conduction in the PV whereas it was maintained in the LA. This could be reproduced in preparations electrically paced at 5 Hz in LA. During pacing at 10 Hz in the PV where high firing rate ectopic foci can occur, cirazoline stopped EFP conduction from the PV to the LA, which allowed the sino-atrial node to resume its pace-making function. Loss of conduction in the PV was associated with depolarization of the diastolic membrane potential of PV cardiomyocytes. Adenosine, which reversed the cirazoline-induced depolarization of the diastolic membrane potential of PV cardiomyocytes, restored full over-shooting action potentials and EFP conduction in the PV. In conclusion, selective activation of α1-adrenergic receptors results in the abolition of electrical conduction within the PV. These results highlight a potentially novel pharmacological approach to treat paroxysmal atrial fibrillation by targeting directly the PV myocardium.
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Affiliation(s)
- Pierre Bredeloux
- EA7349, Laboratoire STIM, Groupe Physiologie des Cellules Cardiaques et Vasculaires, Université de Tours, Tours, France.
| | - Ian Findlay
- EA7349, Laboratoire STIM, Groupe Physiologie des Cellules Cardiaques et Vasculaires, Université de Tours, Tours, France
| | - Côme Pasqualin
- EA7349, Laboratoire STIM, Groupe Physiologie des Cellules Cardiaques et Vasculaires, Université de Tours, Tours, France
| | - Mélèze Hocini
- IHU Liryc, Electrophysiology and Heart Modeling Institute, Fondation Bordeaux Université, Bordeaux, France.,Université de Bordeaux, Centre de Recherche Cardio-Thoracique de Bordeaux, INSERM U1045, Bordeaux, France.,Bordeaux University Hospital (CHU), Cardiac Electrophysiology and Cardiac Stimulation Team, Bordeaux, France
| | - Olivier Bernus
- IHU Liryc, Electrophysiology and Heart Modeling Institute, Fondation Bordeaux Université, Bordeaux, France.,Université de Bordeaux, Centre de Recherche Cardio-Thoracique de Bordeaux, INSERM U1045, Bordeaux, France
| | - Véronique Maupoil
- EA7349, Laboratoire STIM, Groupe Physiologie des Cellules Cardiaques et Vasculaires, Université de Tours, Tours, France
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12
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Takagi D, Okamoto Y, Ohba T, Yamamoto H, Ono K. Comparative study of hyperpolarization-activated currents in pulmonary vein cardiomyocytes isolated from rat, guinea pig, and rabbit. J Physiol Sci 2020; 70:6. [PMID: 32046630 PMCID: PMC7012960 DOI: 10.1186/s12576-020-00736-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2019] [Accepted: 10/03/2019] [Indexed: 02/05/2023]
Abstract
Pulmonary vein (PV) cardiomyocytes have the potential to generate spontaneous activity, in contrast to working myocytes of atria. Different electrophysiological properties underlie the potential automaticity of PV cardiomyocytes, one being the hyperpolarization-activated inward current (Ih), which facilitates the slow diastolic depolarization. In the present study, we examined pharmacological characteristics of the Ih of PV cardiomyocytes in rat, guinea pig and rabbit. The results showed that guinea pig and rat PV cardiomyocytes possessed sizeable amplitudes of the Ih, and the Ih of guinea pig was suppressed by Cs+, a blocker of the hyperpolarization-activated cation current. However, the Ih of rat was not suppressed by Cs+, but by Cd2+, a blocker of the Cl− current. The current density of the Ih of rabbit PV cardiomyocytes was significantly smaller than those of other species. This suggests that the ion channels that carry the Ih of PV cardiomyocytes differ among the animal species.
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Affiliation(s)
- Daichi Takagi
- Department of Cardiovascular Surgery, Akita University Graduate School of Medicine, Hondo 1-1-1, Akita, 010-8543, Japan
| | - Yosuke Okamoto
- Department of Cell Physiology, Akita University Graduate School of Medicine, Hondo 1-1-1, Akita, 010-8543, Japan
| | - Takayoshi Ohba
- Department of Cell Physiology, Akita University Graduate School of Medicine, Hondo 1-1-1, Akita, 010-8543, Japan
| | - Hiroshi Yamamoto
- Department of Cardiovascular Surgery, Akita University Graduate School of Medicine, Hondo 1-1-1, Akita, 010-8543, Japan
| | - Kyoichi Ono
- Department of Cell Physiology, Akita University Graduate School of Medicine, Hondo 1-1-1, Akita, 010-8543, Japan.
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13
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Potekhina VM, Averina OA, Razumov AA, Kuzmin VS, Rozenshtraukh LV. The local repolarization heterogeneity in the murine pulmonary veins myocardium contributes to the spatial distribution of the adrenergically induced ectopic foci. J Physiol Sci 2019; 69:1041-1055. [PMID: 31724110 PMCID: PMC10717041 DOI: 10.1007/s12576-019-00724-2] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2019] [Accepted: 10/23/2019] [Indexed: 12/11/2022]
Abstract
An atrial tachyarrhythmias is predominantly triggered by a proarrhythmic activity originate from the pulmonary veins (PV) myocardial sleeves; sympathetic or adrenergic stimulation facilitates PV proarrhythmia. In the present study the electrophysiological inhomogeneity, spatiotemporal characteristics of the adrenergically induced ectopic firing and sympathetic nerves distribution have been investigated in a murine PV myocardium to clarify mechanisms of adrenergic PV ectopy. Electrically paced murine PV demonstrate atrial-like pattern of conduction and atrial-like action potentials (AP) with longest duration in the mouth of PV. The application of norepinephrine (NE), agonists of α- and β-adrenergic receptors (ARs) or intracardiac nerves stimulation induced spontaneous AP in a form of periodical bursts or continuous firing. NE- or ARs agonists-induced SAP originated from unifocal ectopic foci with predominant localization in the region surrounding PV mouth, but not in the distal portions of a murine PV myocardium. A higher level of catecholamine content and catecholamine fiber network density was revealed in the PV myocardial sleeves relative to LA appendage. However, no significant local variation of catecholamine content and fiber density was observed in the murine PV. In conclusion, PV mouth region appear to be a most susceptible to adrenergic proarrhythmia in mice. Intrinsic spatial heterogeneity of AP duration can be considered as a factor influencing localization of the ectopic foci in PV.
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Affiliation(s)
- V M Potekhina
- Department of Human and Animal Physiology, Biological Faculty, Lomonosov Moscow State University, 1-12 Leninskie Gory, 119234, Moscow, Russia.
| | - O A Averina
- Institute of Functional Genomics, Lomonosov Moscow State University, Moscow, Russia
| | - A A Razumov
- Institute of Natural Sciences and Mathematics, Ural Federal University, Ekaterinburg, Russia
| | - V S Kuzmin
- Department of Human and Animal Physiology, Biological Faculty, Lomonosov Moscow State University, 1-12 Leninskie Gory, 119234, Moscow, Russia
- Pirogov Russian National Research Medical University (RNRMU), Moscow, Russia
| | - L V Rozenshtraukh
- Institute of Experimental Cardiology, National Medicine Research Cardiological Complex, Moscow, Russia
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14
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Egorov YV, Lang D, Tyan L, Turner D, Lim E, Piro ZD, Hernandez JJ, Lodin R, Wang R, Schmuck EG, Raval AN, Ralphe CJ, Kamp TJ, Rosenshtraukh LV, Glukhov AV. Caveolae-Mediated Activation of Mechanosensitive Chloride Channels in Pulmonary Veins Triggers Atrial Arrhythmogenesis. J Am Heart Assoc 2019; 8:e012748. [PMID: 31597508 PMCID: PMC6818041 DOI: 10.1161/jaha.119.012748] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Background Atrial fibrillation often occurs in the setting of hypertension and associated atrial dilation with pathologically increased cardiomyocyte stretch. In the setting of atrial dilation, mechanoelectric feedback has been linked to the development of ectopic beats that trigger paroxysmal atrial fibrillation mainly originating from pulmonary veins (PVs). However, the precise mechanisms remain poorly understood. Methods and Results We identify mechanosensitive, swelling‐activated chloride ion channels (ICl,swell) as a crucial component of the caveolar mechanosensitive complex in rat and human cardiomyocytes. In vitro optical mapping of rat PV, single rat PV, and human cardiomyocyte patch clamp studies showed that stretch‐induced activation of ICl,swell leads to membrane depolarization and decreased action potential amplitude, which trigger conduction discontinuities and both ectopic and reentrant activities within the PV. Reverse transcription quantitative polymerase chain reaction, immunofluorescence, and coimmunoprecipitation studies showed that ICl,swell likely consists of at least 2 components produced by mechanosensitive ClC‐3 (chloride channel‐3) and SWELL1 (also known as LRRC8A [leucine rich repeat containing protein 8A]) chloride channels, which form a macromolecular complex with caveolar scaffolding protein Cav3 (caveolin 3). Downregulation of Cav3 protein expression and disruption of caveolae structures during chronic hypertension in spontaneously hypertensive rats facilitates activation of ICl,swell and increases PV sensitivity to stretch 10‐ to 50‐fold, promoting the development of atrial fibrillation. Conclusions Our findings identify caveolae‐mediated activation of mechanosensitive ICl,swell as a critical cause of PV ectopic beats that can initiate atrial arrhythmias including atrial fibrillation. This mechanism is exacerbated in the setting of chronically elevated blood pressures.
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Affiliation(s)
- Yuriy V. Egorov
- Laboratory of Heart ElectrophysiologyCardiology Research CentreMoscowRussian Federation
| | - Di Lang
- Department of MedicineCardiovascular MedicineUniversity of Wisconsin‐Madison School of Medicine and Public HealthMadisonWI
| | - Leonid Tyan
- Department of MedicineCardiovascular MedicineUniversity of Wisconsin‐Madison School of Medicine and Public HealthMadisonWI
| | - Daniel Turner
- Department of MedicineCardiovascular MedicineUniversity of Wisconsin‐Madison School of Medicine and Public HealthMadisonWI
| | - Evi Lim
- Department of MedicineCardiovascular MedicineUniversity of Wisconsin‐Madison School of Medicine and Public HealthMadisonWI
| | - Zachary D. Piro
- Department of MedicineCardiovascular MedicineUniversity of Wisconsin‐Madison School of Medicine and Public HealthMadisonWI
| | - Jonathan J. Hernandez
- Department of MedicineCardiovascular MedicineUniversity of Wisconsin‐Madison School of Medicine and Public HealthMadisonWI
- Department of PediatricsPediatric CardiologyUniversity of Wisconsin‐Madison School of Medicine and Public HealthMadisonWI
| | - Rylie Lodin
- Department of MedicineCardiovascular MedicineUniversity of Wisconsin‐Madison School of Medicine and Public HealthMadisonWI
| | - Rose Wang
- Department of MedicineCardiovascular MedicineUniversity of Wisconsin‐Madison School of Medicine and Public HealthMadisonWI
| | - Eric G. Schmuck
- Department of MedicineCardiovascular MedicineUniversity of Wisconsin‐Madison School of Medicine and Public HealthMadisonWI
| | - Amish N. Raval
- Department of MedicineCardiovascular MedicineUniversity of Wisconsin‐Madison School of Medicine and Public HealthMadisonWI
| | - Carter J. Ralphe
- Department of PediatricsPediatric CardiologyUniversity of Wisconsin‐Madison School of Medicine and Public HealthMadisonWI
| | - Timothy J. Kamp
- Department of MedicineCardiovascular MedicineUniversity of Wisconsin‐Madison School of Medicine and Public HealthMadisonWI
| | | | - Alexey V. Glukhov
- Department of MedicineCardiovascular MedicineUniversity of Wisconsin‐Madison School of Medicine and Public HealthMadisonWI
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15
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Okamoto Y, Nagasawa Y, Obara Y, Ishii K, Takagi D, Ono K. Molecular identification of HSPA8 as an accessory protein of a hyperpolarization-activated chloride channel from rat pulmonary vein cardiomyocytes. J Biol Chem 2019; 294:16049-16061. [PMID: 31506297 DOI: 10.1074/jbc.ra119.007416] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2019] [Revised: 08/28/2019] [Indexed: 12/26/2022] Open
Abstract
Pulmonary veins (PVs) are the major origin of atrial fibrillation. Recently, we recorded hyperpolarization-activated Cl- current (I Cl, h) in rat PV cardiomyocytes. Unlike the well-known chloride channel protein 2 (CLCN2) current, the activation curve of I Cl, h was hyperpolarized as the Cl- ion concentration ([Cl-] i ) increased. This current could account for spontaneous activity in PV cardiomyocytes linked to atrial fibrillation. In this study, we aimed to identify the channel underlying I Cl, h Using RT-PCR amplification specific for Clcn2 or its homologs, a chloride channel was cloned from rat PV and detected in rat PV cardiomyocytes using immunocytochemistry. The gene sequence and electrophysiological functions of the protein were identical to those previously reported for Clcn2, with protein activity observed as a hyperpolarization-activated current by the patch-clamp method. However, the [Cl-] i dependence of activation was entirely different from the observed I Cl, h of PV cardiomyocytes; the activation curve of the Clcn2-transfected cells shifted toward positive potential with increased [Cl-] i , whereas the I Cl, h of PV and left ventricular cardiomyocytes showed a leftward shift. Therefore, we used MS to explore the possibility of additional proteins interacting with CLCN2 and identified an individual 71-kDa protein, HSPA8, that was strongly expressed in rat PV cardiomyocytes. With co-expression of HSPA8 in HEK293 and PC12 cells, the CLCN2 current showed voltage-dependent activation and shifted to negative potential with increasing [Cl-] i Molecular docking simulations further support an interaction between CLCN2 and HSPA8. These findings suggest that CLCN2 in rat heart contains HSPA8 as a unique accessory protein.
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Affiliation(s)
- Yosuke Okamoto
- Department of Cell Physiology, Akita Graduate School of Medicine, 1-1-1 Hondo, Akita 010-8543, Japan
| | - Yoshinobu Nagasawa
- Department of Pharmacology and Therapeutics, Faculty of Pharmaceutical Sciences, Toho University, Chiba 274-8510, Japan
| | - Yutaro Obara
- Department of Pharmacology, Yamagata University Faculty of Medicine, 2-2-2 Iida-nishi, Yamagata 990-9585, Japan
| | - Kuniaki Ishii
- Department of Pharmacology, Yamagata University Faculty of Medicine, 2-2-2 Iida-nishi, Yamagata 990-9585, Japan
| | - Daichi Takagi
- Department of Cell Physiology, Akita Graduate School of Medicine, 1-1-1 Hondo, Akita 010-8543, Japan
| | - Kyoichi Ono
- Department of Cell Physiology, Akita Graduate School of Medicine, 1-1-1 Hondo, Akita 010-8543, Japan
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16
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Umehara S, Tan X, Okamoto Y, Ono K, Noma A, Amano A, Himeno Y. Mechanisms Underlying Spontaneous Action Potential Generation Induced by Catecholamine in Pulmonary Vein Cardiomyocytes: A Simulation Study. Int J Mol Sci 2019; 20:ijms20122913. [PMID: 31207916 PMCID: PMC6628582 DOI: 10.3390/ijms20122913] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2019] [Revised: 06/11/2019] [Accepted: 06/12/2019] [Indexed: 12/24/2022] Open
Abstract
Cardiomyocytes and myocardial sleeves dissociated from pulmonary veins (PVs) potentially generate ectopic automaticity in response to noradrenaline (NA), and thereby trigger atrial fibrillation. We developed a mathematical model of rat PV cardiomyocytes (PVC) based on experimental data that incorporates the microscopic framework of the local control theory of Ca2+ release from the sarcoplasmic reticulum (SR), which can generate rhythmic Ca2+ release (limit cycle revealed by the bifurcation analysis) when total Ca2+ within the cell increased. Ca2+ overload in SR increased resting Ca2+ efflux through the type II inositol 1,4,5-trisphosphate (IP3) receptors (InsP3R) as well as ryanodine receptors (RyRs), which finally triggered massive Ca2+ release through activation of RyRs via local Ca2+ accumulation in the vicinity of RyRs. The new PVC model exhibited a resting potential of −68 mV. Under NA effects, repetitive Ca2+ release from SR triggered spontaneous action potentials (APs) by evoking transient depolarizations (TDs) through Na+/Ca2+ exchanger (APTDs). Marked and variable latencies initiating APTDs could be explained by the time courses of the α1- and β1-adrenergic influence on the regulation of intracellular Ca2+ content and random occurrences of spontaneous TD activating the first APTD. Positive and negative feedback relations were clarified under APTD generation.
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Affiliation(s)
- Shohei Umehara
- Department of Bioinformatics, College of Life Sciences, Ritsumeikan University, Shiga 525-8577, Japan.
| | - Xiaoqiu Tan
- Institute of Cardiovascular Research, Southwest Medical University, Luzhou 640000, China.
| | - Yosuke Okamoto
- Department of Cell Physiology, Graduate School of Medicine, Akita University, Akita 010-8543, Japan.
| | - Kyoichi Ono
- Department of Cell Physiology, Graduate School of Medicine, Akita University, Akita 010-8543, Japan.
| | - Akinori Noma
- Department of Bioinformatics, College of Life Sciences, Ritsumeikan University, Shiga 525-8577, Japan.
| | - Akira Amano
- Department of Bioinformatics, College of Life Sciences, Ritsumeikan University, Shiga 525-8577, Japan.
| | - Yukiko Himeno
- Department of Bioinformatics, College of Life Sciences, Ritsumeikan University, Shiga 525-8577, Japan.
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17
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Angiotensin II Induces Automatic Activity of the Isolated Guinea Pig Pulmonary Vein Myocardium through Activation of the IP₃ Receptor and the Na⁺-Ca 2+ Exchanger. Int J Mol Sci 2019; 20:ijms20071768. [PMID: 30974804 PMCID: PMC6479489 DOI: 10.3390/ijms20071768] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2019] [Revised: 04/01/2019] [Accepted: 04/05/2019] [Indexed: 11/16/2022] Open
Abstract
The automaticity of the pulmonary vein myocardium is known to be the major cause of atrial fibrillation. We examined the involvement of angiotensin II in the automatic activity of isolated guinea pig pulmonary vein preparations. In tissue preparations, application of angiotensin II induced an automatic contractile activity; this effect was mimicked by angiotensin I and blocked by losartan, but not by PD123,319 or carvedilol. In cardiomyocytes, application of angiotensin II induced an increase in the frequency of spontaneous Ca2+ sparks and the generation of Ca2+ transients; these effects were inhibited by losartan or xestospongin C. In tissue preparations, angiotensin II caused membrane potential oscillations, which lead to repetitive generation of action potentials. Angiotensin II increased the diastolic depolarization slope of the spontaneous or evoked action potentials. These effects of angiotensin II were inhibited by SEA0400. In tissue preparations showing spontaneous firing of action potentials, losartan, xestospongin C or SEA0400 decreased the slope of the diastolic depolarization and inhibited the firing of action potentials. In conclusion, in the guinea pig pulmonary vein myocardium, angiotensin II induces the generation of automatic activity through activation of the IP3 receptor and the Na+-Ca2+ exchanger.
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18
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Ivanova AD, Kuzmin VS. Electrophysiological characteristics of the rat azygos vein under electrical pacing and adrenergic stimulation. J Physiol Sci 2018; 68:617-628. [PMID: 28929393 PMCID: PMC10717306 DOI: 10.1007/s12576-017-0569-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2017] [Accepted: 09/12/2017] [Indexed: 02/04/2023]
Abstract
Rodent thoracic veins are characterized by an extended myocardial coating. In the present study, the electrical activity in the cardiac tissue of the rat azygos vein (AZV) was investigated for the first time. The atrial-like action potentials (AP) and atrial-like conduction of the excitation were observed in the rat AZV under continuous electrical pacing. Termination of electrical pacing resulted in spontaneous positive shift of resting membrane potential (RMP) in AZV. Boradrenaline induced biphasic effects on RMP in all quiescent AZV preparations but only in 25% preparations-bursts of spontaneous AP, which were suppressed by both α- and β-adrenoreceptor antagonists. Phenylephrine induced additional depolarization of RMP in quiescent AZV preparations, while isoproterenol caused hyperpolarization. In conclusion, bioelectrical properties of the rat AZV resemble those of atrial myocardium under continuous electrical pacing; however, depolarized RMP and NA-induced spontaneous AP characterize AZV as a tissue prone to rare automaticity.
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Affiliation(s)
| | - Vlad S Kuzmin
- Biological Department, Moscow State University, Moscow, Russia
- Pirogov Russian National Research Medical University, Moscow, Russia
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19
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Kashino Y, Obara Y, Okamoto Y, Saneyoshi T, Hayashi Y, Ishii K. ERK5 Phosphorylates K v4.2 and Inhibits Inactivation of the A-Type Current in PC12 Cells. Int J Mol Sci 2018; 19:ijms19072008. [PMID: 29996472 PMCID: PMC6073465 DOI: 10.3390/ijms19072008] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2018] [Revised: 06/28/2018] [Accepted: 06/28/2018] [Indexed: 12/31/2022] Open
Abstract
Extracellular signal-regulated kinase 5 (ERK5) regulates diverse physiological responses such as proliferation, differentiation, and gene expression. Previously, we demonstrated that ERK5 is essential for neurite outgrowth and catecholamine biosynthesis in PC12 cells and sympathetic neurons. However, it remains unclear how ERK5 regulates the activity of ion channels, which are important for membrane excitability. Thus, we examined the effect of ERK5 on the ion channel activity in the PC12 cells that overexpress both ERK5 and the constitutively active MEK5 mutant. The gene and protein expression levels of voltage-dependent Ca2+ and K+ channels were determined by RT-qPCR or Western blotting. The A-type K+ current was recorded using the whole-cell patch clamp method. In these ERK5-activated cells, the gene expression levels of voltage-dependent L- and P/Q-type Ca2+ channels did not alter, but the N-type Ca2+ channel was slightly reduced. In contrast, those of Kv4.2 and Kv4.3, which are components of the A-type current, were significantly enhanced. Unexpectedly, the protein levels of Kv4.2 were not elevated by ERK5 activation, but the phosphorylation levels were increased by ERK5 activation. By electrophysiological analysis, the inactivation time constant of the A-type current was prolonged by ERK5 activation, without changes in the peak current. Taken together, ERK5 inhibits an inactivation of the A-type current by phosphorylation of Kv4.2, which may contribute to the neuronal differentiation process.
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Affiliation(s)
- Yurina Kashino
- Department of Pharmacology, Yamagata University School of Medicine, Yamagata 990-9585, Japan.
| | - Yutaro Obara
- Department of Pharmacology, Yamagata University School of Medicine, Yamagata 990-9585, Japan.
| | - Yosuke Okamoto
- Department of Pharmacology, Yamagata University School of Medicine, Yamagata 990-9585, Japan.
| | - Takeo Saneyoshi
- Department of Pharmacology, Kyoto University Graduate School of Medicine, Kyoto 606-8501, Japan.
| | - Yasunori Hayashi
- Department of Pharmacology, Kyoto University Graduate School of Medicine, Kyoto 606-8501, Japan.
| | - Kuniaki Ishii
- Department of Pharmacology, Yamagata University School of Medicine, Yamagata 990-9585, Japan.
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20
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Ivanova AD, Kuzmin VS, Rosenshtraukh LV. β-Adrenergic stimulation induces pro-arrhythmic activity in the caval vein myocardial tissue. DOKLADY BIOLOGICAL SCIENCES : PROCEEDINGS OF THE ACADEMY OF SCIENCES OF THE USSR, BIOLOGICAL SCIENCES SECTIONS 2017; 476:183-187. [PMID: 29101618 DOI: 10.1134/s0012496617050027] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/27/2017] [Indexed: 11/23/2022]
Abstract
Electrical activity of the right superior vena cava (SVC) is considered as a source of the atrial fibrillation. We have shown that bioelectrical properties of the SVC myocardium differ from those of the working atrial myocardium. Electrically evoked action potential duration in SVC is significantly shorter, the resting membrane potential in both stimulated and quiescent SVC preparations is significantly more positive than in atria. Activation of β-adrenoreceptors in SVC myocardium leads to a series of action potentials, and this process depends on protein kinase A. Probably, β-adrenergic stimulation enhances SVC arrhythmogenesis in vivo.
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Affiliation(s)
- A D Ivanova
- Department of Human and Animal Physiology, Biological Faculty, Moscow State University, Moscow, Russia.
| | - V S Kuzmin
- Department of Human and Animal Physiology, Biological Faculty, Moscow State University, Moscow, Russia.,Pirogov National Research Medical University, Ministry of Health, Moscow, Russia
| | - L V Rosenshtraukh
- Institute of Experimental Cardiology, Russian Cardiology Research Center, Ministry of Health, Moscow, Russia
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21
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Tsuneoka Y, Irie M, Tanaka Y, Sugimoto T, Kobayashi Y, Kusakabe T, Kato K, Hamaguchi S, Namekata I, Tanaka H. Permissive role of reduced inwardly-rectifying potassium current density in the automaticity of the guinea pig pulmonary vein myocardium. J Pharmacol Sci 2017; 133:195-202. [PMID: 28410965 DOI: 10.1016/j.jphs.2016.12.006] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2016] [Revised: 12/12/2016] [Accepted: 12/18/2016] [Indexed: 10/19/2022] Open
Abstract
The electrophysiological properties underlying the automaticity of the guinea pig pulmonary vein myocardium were studied. About 30% of the isolated pulmonary vein tissue preparations showed spontaneous electrical activity, as shown by glass microelectrode recordings from their myocardial layer. The remaining quiescent preparations had a resting membrane potential less negative than that in the left atria. Blockade of the acetylcholine activated potassium current (IK-ACh) by tertiapin induced a depolarizing shift of the resting membrane potential and automatic electrical activity in the pulmonary vein, but not in the atria. The tertiapin-induced electrical activity, as well as the spontaneous activity, was inhibited by the application of carbachol or by chelation of intracellular Ca2+ by BAPTA. The isolated pulmonary vein cardiomyocytes had an IK-ACh density similar to that of the atrial cardiomyocytes, but a lower density of the inwardly-rectifying potassium current (IK1). Spontaneous Ca2+ transients were observed in about 30% of the isolated pulmonary vein cardiomyocytes, but not in atrial cardiomyocytes. The Ca2+ transients in the pulmonary vein cardiomyocytes were induced by tertiapin and inhibited by carbachol. These results indicate that the pulmonary vein cardiomyocytes have a reduced density of the inwardly-rectifying potassium current, which plays a permissive role in their intracellular Ca2+-dependent automaticity.
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Affiliation(s)
- Yayoi Tsuneoka
- Department of Pharmacology, Faculty of Pharmaceutical Sciences, Toho University, Funabashi, Chiba 274-8510, Japan; Laboratory of Pharmacology, Faculty of Pharmaceutical Science, Tokyo University of Sciences, Noda, Chiba 278-8510, Japan
| | - Masahiko Irie
- Department of Pharmacology, Faculty of Pharmaceutical Sciences, Toho University, Funabashi, Chiba 274-8510, Japan
| | - Yusuke Tanaka
- Department of Pharmacology, Faculty of Pharmaceutical Sciences, Toho University, Funabashi, Chiba 274-8510, Japan
| | - Takahiko Sugimoto
- Department of Pharmacology, Faculty of Pharmaceutical Sciences, Toho University, Funabashi, Chiba 274-8510, Japan
| | - Yuka Kobayashi
- Department of Pharmacology, Faculty of Pharmaceutical Sciences, Toho University, Funabashi, Chiba 274-8510, Japan
| | - Taichi Kusakabe
- Department of Organic Chemistry, Faculty of Pharmaceutical Sciences, Toho University, Funabashi, Chiba 274-8510, Japan
| | - Keisuke Kato
- Department of Organic Chemistry, Faculty of Pharmaceutical Sciences, Toho University, Funabashi, Chiba 274-8510, Japan
| | - Shogo Hamaguchi
- Department of Pharmacology, Faculty of Pharmaceutical Sciences, Toho University, Funabashi, Chiba 274-8510, Japan.
| | - Iyuki Namekata
- Department of Pharmacology, Faculty of Pharmaceutical Sciences, Toho University, Funabashi, Chiba 274-8510, Japan
| | - Hikaru Tanaka
- Department of Pharmacology, Faculty of Pharmaceutical Sciences, Toho University, Funabashi, Chiba 274-8510, Japan
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22
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Egorov YV, Kuz'min VS, Glukhov AV, Rosenshtraukh LV. Electrophysiological Characteristics, Rhythm, Disturbances and Conduction Discontinuities Under Autonomic Stimulation in the Rat Pulmonary Vein Myocardium. J Cardiovasc Electrophysiol 2015; 26:1130-9. [PMID: 26086390 DOI: 10.1111/jce.12738] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/03/2015] [Revised: 06/01/2015] [Accepted: 06/10/2015] [Indexed: 11/27/2022]
Abstract
INTRODUCTION Despite the importance of neurogenic initiation of rapid firing from pulmonary veins (PVs), the mechanism of autonomic modulation of electrophysiological properties of the PV myocardium to form a substrate for atrial arrhythmia remains poorly understood. METHODS AND RESULTS A 2-microelectrode technique was used to characterize electrophysiological properties of rat PV myocardium and to explore PV arrhythmogenesis, at baseline, during electrical stimulation and/or under autonomic modulation. PV myocardium was characterized by prolonged action potential duration (APD), high degree of APD alternans, and spontaneous depolarizations. Autonomic stimulation resulted in significantly enhanced APD dispersion within the PV, which dynamically changed over time and was associated with intra-PV and atria-PV conduction blocks and could lead to spontaneous fibrillation-like high-frequency activity. In the distal part of the PV we found an unexcitable area that was characterized by depolarized resting potential (-50 ± 4 mV vs. -75 ± 2 mV vs. PV mouth, P < 0.01). This region could be activated during autonomic stimulation or fast pacing that led to multiple conduction discontinuities (uni- and bi-directional conduction blocks, Wenckebach periodicity, electrotonic modulation conduction block, echo phenomenon) in 17/23 preparations, including those occurring under norepinephrine superfusion (14/17) and during pacing frequency changes (3/17). PV echoes (unstable reentrant circuits) were found in 8/23 preparations. In some experiments, several types of conduction abnormalities were observed. CONCLUSION The PV myocardium demonstrates distinct electrophysiological characteristics, which could be considerably exaggerated by electrical stimulation and/or autonomic nervous system to dynamically form a functional substrate to support re-entry as well as focal activity.
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Affiliation(s)
- Yuriy V Egorov
- Laboratory of Heart Electrophysiology, Cardiology Research Centre, Moscow, Russian Federation, Russia.,Department of Cardiovascular Sciences, National Heart and Lung Institute, Imperial College, London, UK
| | - Vladislav S Kuz'min
- Laboratory of Heart Electrophysiology, Cardiology Research Centre, Moscow, Russian Federation, Russia.,Pirogov Russian National Research Medical University (RNRMU), Moscow, Russian Federation.,Department of Cardiovascular Sciences, National Heart and Lung Institute, Imperial College, London, UK
| | - Alexey V Glukhov
- Laboratory of Heart Electrophysiology, Cardiology Research Centre, Moscow, Russian Federation, Russia.,Department of Cardiovascular Sciences, National Heart and Lung Institute, Imperial College, London, UK
| | - Leonid V Rosenshtraukh
- Laboratory of Heart Electrophysiology, Cardiology Research Centre, Moscow, Russian Federation, Russia.,Department of Cardiovascular Sciences, National Heart and Lung Institute, Imperial College, London, UK
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