1
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Cheng H, Kong CHT, James AF, Cannell MB, Hancox JC. Modulation of Spontaneous Action Potential Rate by Inositol Trisphosphate in Myocytes from the Rabbit Atrioventricular Node. Cells 2024; 13:1455. [PMID: 39273026 PMCID: PMC11394215 DOI: 10.3390/cells13171455] [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: 07/22/2024] [Revised: 08/08/2024] [Accepted: 08/26/2024] [Indexed: 09/15/2024] Open
Abstract
The atrioventricular node (AVN) is a key component of the cardiac conduction system and takes over pacemaking of the ventricles if the sinoatrial node fails. IP3 (inositol 1,4,5 trisphosphate) can modulate excitability of myocytes from other regions of the heart, but it is not known whether IP3 receptor (IP3-R) activation modulates AVN cell pacemaking. Consequently, this study investigated effects of IP3 on spontaneous action potentials (APs) from AVN cells isolated from rabbit hearts. Immunohistochemistry and confocal imaging demonstrated the presence of IP3-R2 in isolated AVN cells, with partial overlap with RyR2 ryanodine receptors seen in co-labelling experiments. In whole-cell recordings at physiological temperature, application of 10 µM membrane-permeant Bt3-(1,4,5)IP3-AM accelerated spontaneous AP rate and increased diastolic depolarization rate, without direct effects on ICa,L, IKr, If or INCX. By contrast, application via the patch pipette of 5 µM of the IP3-R inhibitor xestospongin C led to a slowing in spontaneous AP rate and prevented 10 µM Bt3-(1,4,5)IP3-AM application from increasing the AP rate. UV excitation of AVN cells loaded with caged-IP3 led to an acceleration in AP rate, the magnitude of which increased with the extent of UV excitation. 2-APB slowed spontaneous AP rate, consistent with a role for constitutive IP3-R activity; however, it was also found to inhibit ICa,L and IKr, confounding its use for studying IP3-R. Under AP voltage clamp, UV excitation of AVN cells loaded with caged IP3 activated an inward current during diastolic depolarization. Collectively, these results demonstrate that IP3 can modulate AVN cell pacemaking rate.
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Affiliation(s)
- Hongwei Cheng
- School of Physiology, Pharmacology and Neuroscience, University of Bristol, Biomedical Sciences Building, University Walk, Bristol BS8 1TD, UK
| | - Cherrie H T Kong
- School of Physiology, Pharmacology and Neuroscience, University of Bristol, Biomedical Sciences Building, University Walk, Bristol BS8 1TD, UK
| | - Andrew F James
- School of Physiology, Pharmacology and Neuroscience, University of Bristol, Biomedical Sciences Building, University Walk, Bristol BS8 1TD, UK
| | - Mark B Cannell
- School of Physiology, Pharmacology and Neuroscience, University of Bristol, Biomedical Sciences Building, University Walk, Bristol BS8 1TD, UK
| | - Jules C Hancox
- School of Physiology, Pharmacology and Neuroscience, University of Bristol, Biomedical Sciences Building, University Walk, Bristol BS8 1TD, UK
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2
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Saito T, Suzuki M, Ohba A, Hamaguchi S, Namekata I, Tanaka H. Enhanced Late I Na Induces Intracellular Ion Disturbances and Automatic Activity in the Guinea Pig Pulmonary Vein Cardiomyocytes. Int J Mol Sci 2024; 25:8688. [PMID: 39201376 PMCID: PMC11354854 DOI: 10.3390/ijms25168688] [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: 06/30/2024] [Revised: 07/30/2024] [Accepted: 08/07/2024] [Indexed: 09/02/2024] Open
Abstract
The effects of enhanced late INa, a persistent component of the Na+ channel current, on the intracellular ion dynamics and the automaticity of the pulmonary vein cardiomyocytes were studied with fluorescent microscopy. Anemonia viridis toxin II (ATX- II), an enhancer of late INa, caused increases in the basal Na+ and Ca2+ concentrations, increases in the number of Ca2+ sparks and Ca2+ waves, and the generation of repetitive Ca2+ transients. These phenomena were inhibited by eleclazine, a blocker of the late INa; SEA0400, an inhibitor of the Na+/Ca2+ exchanger (NCX); H89, a protein kinase A (PKA) inhibitor; and KN-93, a Ca2+/calmodulin-dependent protein kinase II (CaMKII) inhibitor. These results suggest that enhancement of late INa in the pulmonary vein cardiomyocytes causes disturbance of the intracellular ion environment through activation of the NCX and Ca2+-dependent enzymes. Such mechanisms are probably involved in the ectopic electrical activity of the pulmonary vein myocardium.
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Affiliation(s)
| | | | | | | | - Iyuki Namekata
- Department of Pharmacology, Faculty of Pharmaceutical Sciences, Toho University, 2-2-1 Miyama Funabashi, Chiba 274-8510, Japan; (T.S.); (M.S.); (A.O.); (S.H.); (H.T.)
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3
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Regional Differences in Ca 2+ Signaling and Transverse-Tubules across Left Atrium from Adult Sheep. Int J Mol Sci 2023; 24:ijms24032347. [PMID: 36768669 PMCID: PMC9916916 DOI: 10.3390/ijms24032347] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2022] [Revised: 01/18/2023] [Accepted: 01/19/2023] [Indexed: 01/27/2023] Open
Abstract
Cardiac excitation-contraction coupling can be different between regions of the heart. Little is known at the atria level, specifically in different regions of the left atrium. This is important given the role of cardiac myocytes from the pulmonary vein sleeves, which are responsible for ectopic activity during atrial fibrillation. In this study, we present a new method to isolate atrial cardiac myocytes from four different regions of the left atrium of a large animal model, sheep, highly relevant to humans. Using collagenase/protease we obtained calcium-tolerant atrial cardiac myocytes from the epicardium, endocardium, free wall and pulmonary vein regions. Calcium transients were slower (time to peak and time to decay) in free wall and pulmonary vein myocytes compared to the epicardium and endocardium. This is associated with lower t-tubule density. Overall, these results suggest regional differences in calcium transient and t-tubule density across left atria, which may play a major role in the genesis of atrial fibrillation.
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4
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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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5
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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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6
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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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7
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Tsumoto K, Kurata Y. Bifurcations and Proarrhythmic Behaviors in Cardiac Electrical Excitations. Biomolecules 2022; 12:459. [PMID: 35327651 PMCID: PMC8946197 DOI: 10.3390/biom12030459] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [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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Affiliation(s)
| | - Yasutaka Kurata
- Department of Physiology II, Kanazawa Medical University, Uchinada 920-0293, Japan;
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8
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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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9
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Mi X, Ding WG, Toyoda F, Kojima A, Omatsu-Kanbe M, Matsuura H. Selective activation of adrenoceptors potentiates I Ks current in pulmonary vein cardiomyocytes through the protein kinase A and C signaling pathways. J Mol Cell Cardiol 2021; 161:86-97. [PMID: 34375616 DOI: 10.1016/j.yjmcc.2021.08.004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/25/2021] [Revised: 07/19/2021] [Accepted: 08/04/2021] [Indexed: 10/20/2022]
Abstract
Delayed rectifier K+ current (IKs) is a key contributor to repolarization of action potentials. This study investigated the mechanisms underlying the adrenoceptor-induced potentiation of IKs in pulmonary vein cardiomyocytes (PVC). PVC were isolated from guinea pig pulmonary vein. The action potentials and IKs current were recorded using perforated and conventional whole-cell patch-clamp techniques. The expression of IKs was examined using immunocytochemistry and Western blotting. KCNQ1, a IKs pore-forming protein was detected as a signal band approximately 100 kDa in size, and its immunofluorescence signal was found to be mainly localized on the cell membrane. The IKs current in PVC was markedly enhanced by both β1- and β2-adrenoceptor stimulation with a negative voltage shift in the current activation, although the potentiation was more effectively induced by β2-adrenoceptor stimulation than β1-adrenoceptor stimulation. Both β-adrenoceptor-mediated increases in IKs were attenuated by treatment with the adenylyl cyclase (AC) inhibitor or protein kinase A (PKA) inhibitor. Furthermore, the IKs current was increased by α1-adrenoceptor agonist but attenuated by the protein kinase C (PKC) inhibitor. PVC exhibited action potentials in normal Tyrode solution which was slightly reduced by HMR-1556 a selective IKs blocker. However, HMR-1556 markedly reduced the β-adrenoceptor-potentiated firing rate. The stimulatory effects of β- and α1-adrenoceptor on IKs in PVC are mediated via the PKA and PKC signal pathways. HMR-1556 effectively reduced the firing rate under β-adrenoceptor activation, suggesting that the functional role of IKs might increase during sympathetic excitation under in vivo conditions.
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Affiliation(s)
- Xinya Mi
- Department of Physiology, Shiga University of Medical Science, Otsu, Shiga, Japan
| | - Wei-Guang Ding
- Department of Physiology, Shiga University of Medical Science, Otsu, Shiga, Japan.
| | - Futoshi Toyoda
- Department of Physiology, Shiga University of Medical Science, Otsu, Shiga, Japan
| | - Akiko Kojima
- Department of Anesthesiology, Shiga University of Medical Science, Otsu, Shiga, Japan
| | - Mariko Omatsu-Kanbe
- Department of Physiology, Shiga University of Medical Science, Otsu, Shiga, Japan
| | - Hiroshi Matsuura
- Department of Physiology, Shiga University of Medical Science, Otsu, Shiga, Japan
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10
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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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11
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Ivanova AD, Filatova TS, Abramochkin DV, Atkinson A, Dobrzynski H, Kokaeva ZG, Merzlyak EM, Pustovit KB, Kuzmin VS. Attenuation of inward rectifier potassium current contributes to the α1-adrenergic receptor-induced proarrhythmicity in the caval vein myocardium. Acta Physiol (Oxf) 2021; 231:e13597. [PMID: 33306261 DOI: 10.1111/apha.13597] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2020] [Revised: 11/19/2020] [Accepted: 12/07/2020] [Indexed: 12/31/2022]
Abstract
AIM This study is aimed at investigation of electrophysiological effects of α1-adrenoreceptor (α1-AR) stimulation in the rat superior vena cava (SVC) myocardium, which is one of the sources of proarrhythmic activity. METHODS α1-ARs agonists (phenylephrine-PHE or norepinephrine in presence of atenolol-NE + ATL) were applied to SVC and atrial tissue preparations or isolated cardiomyocytes, which were examined using optical mapping, glass microelectrodes or whole-cell patch clamp. α1-ARs distribution was evaluated using immunofluorescence. Kir2.X mRNA and protein level were estimated using RT-PCR and Western blotting. RESULTS PHE or NE + ATL application caused a significant suppression of the conduction velocity (CV) of excitation and inexcitability in SVC, an increase in the duration of electrically evoked action potentials (APs), a decrease in the maximum upstroke velocity (dV/dtmax ) and depolarization of the resting membrane potential (RMP) in SVC to a greater extent than in atria. The effects induced by α1-ARs activation in SVC were attenuated by protein kinase C inhibition (PKC). The whole-cell patch clamp revealed PHE-induced suppression of outward component of IK1 inward rectifier current in isolated SVC, but not atrial myocytes. These effects can be mediated by α1A subtype of α-ARs found in abundance in rat SVC. The basal IK1 level in SVC was much lower than in atria as a result of the weaker expression of Kir2.2 channels. CONCLUSION Therefore, the reduced density of IK1 in rat SVC cardiomyocytes and sensitivity of this current to α1A-AR stimulation via PKC-dependent pathways might lead to proarrhythmic conduction in SVC myocardium by inducing RMP depolarization, AP prolongation, CV and dV/dtmax decrease.
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Affiliation(s)
- Alexandra D. Ivanova
- Department of Human and Animal Physiology Lomonosov Moscow State University Moscow Russia
| | - Tatiana S. Filatova
- Department of Human and Animal Physiology Lomonosov Moscow State University Moscow Russia
- Department of Physiology Pirogov Russian National Research Medical University Moscow Russia
| | - Denis V. Abramochkin
- Department of Human and Animal Physiology Lomonosov Moscow State University Moscow Russia
- Department of Physiology Pirogov Russian National Research Medical University Moscow Russia
- Laboratory of Cardiac Electrophysiology National Medical Research Center for Cardiology Moscow Russia
| | - Andrew Atkinson
- Faculty of Biology, Medicine and Health University of Manchester Manchester UK
| | - Halina Dobrzynski
- Faculty of Biology, Medicine and Health University of Manchester Manchester UK
- Heart Embryology and Anatomy Research Team Department of Anatomy Jagiellonian University Medical College Cracow Poland
| | - Zarema G. Kokaeva
- Department of Human and Animal Physiology Lomonosov Moscow State University Moscow Russia
| | - Ekaterina M. Merzlyak
- Shemiakin‐Ovchinnikov Institute of Bioorganic Chemistry Russian Academy of Science Moscow Russia
| | - Ksenia B. Pustovit
- Department of Human and Animal Physiology Lomonosov Moscow State University Moscow Russia
| | - Vladislav S. Kuzmin
- Department of Human and Animal Physiology Lomonosov Moscow State University Moscow Russia
- Department of Physiology Pirogov Russian National Research Medical University Moscow Russia
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12
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Bond RC, Choisy SC, Bryant SM, Hancox JC, James AF. Ion currents, action potentials, and noradrenergic responses in rat pulmonary vein and left atrial cardiomyocytes. Physiol Rep 2020; 8:e14432. [PMID: 32401431 PMCID: PMC7219272 DOI: 10.14814/phy2.14432] [Citation(s) in RCA: 4] [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: 09/06/2019] [Revised: 04/06/2020] [Accepted: 04/10/2020] [Indexed: 11/30/2022] Open
Abstract
The electrophysiological properties of pulmonary vein (PV)-cardiomyocytes, and their responses to the sympathetic neurotransmitter, noradrenaline (NA), are thought to differ from those of the left atrium (LA) and contribute to atrial ectopy. The aim of this study was to examine rat PV cardiomyocyte electrophysiology and responses to NA in comparison with LA cells. LA and PV cardiomyocytes were isolated from adult male Wistar rat hearts, and membrane potentials and ion currents recorded at 36°C using whole-cell patch-clamp techniques. PV and LA cardiomyocytes did not differ in size. In control, there were no differences between the two cell-types in zero-current potential or action potential duration (APD) at 1 Hz, although the incidence of early afterdepolarizations (EADs) was greater in PV than LA cardiomyocytes. The L-type Ca2+ current (ICaL ) was ~×1.5 smaller (p = .0029, Student's t test) and the steady-state K+ current (IKss ) was ~×1.4 larger (p = .0028, Student's t test) in PV than in LA cardiomyocytes. PV cardiomyocyte inward-rectifier current (IK1 ) was slightly smaller than LA cardiomyocyte IK1 . In LA cardiomyocytes, NA significantly prolonged APD30 . In PV cells, APD30 responses to 1 μM NA were heterogeneous: while the mean percentage change in APD30 was not different from 0 (16.5 ± 9.7%, n cells/N animals = 12/10, p = .1177, one-sample t test), three cells showed shortening (-18.8 ± 6.0%) whereas nine showed prolongation (28.3 ± 10.1%, p = .008, Student's t test). NA had no effect on IK1 in either cell-type but inhibited PV IKss by 41.9 ± 4.1% (n/N = 23/11 p < .0001), similar to LA cells. NA increased ICaL in most PV cardiomyocytes (median × 2.2-increase, p < .0001, n/N = 32/14, Wilcoxon-signed-rank test), although in 7/32 PV cells ICaL was decreased following NA. PV cardiomyocytes differ from LA cells and respond heterogeneously to NA.
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Affiliation(s)
- Richard C. Bond
- Cardiovascular Research LaboratoriesSchool of PhysiologyBiomedical Sciences BuildingUniversity of BristolBristolUK
| | - Stéphanie C. Choisy
- Cardiovascular Research LaboratoriesSchool of PhysiologyBiomedical Sciences BuildingUniversity of BristolBristolUK
| | - Simon M. Bryant
- Cardiovascular Research LaboratoriesSchool of PhysiologyBiomedical Sciences BuildingUniversity of BristolBristolUK
| | - Jules C. Hancox
- Cardiovascular Research LaboratoriesSchool of PhysiologyBiomedical Sciences BuildingUniversity of BristolBristolUK
| | - Andrew F. James
- Cardiovascular Research LaboratoriesSchool of PhysiologyBiomedical Sciences BuildingUniversity of BristolBristolUK
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13
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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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14
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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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15
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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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16
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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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17
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Nakanishi H, Lee JK, Miwa K, Masuyama K, Yasutake H, Li J, Tomoyama S, Honda Y, Deguchi J, Tsujimoto S, Hidaka K, Miyagawa S, Sawa Y, Komuro I, Sakata Y. Geometrical Patterning and Constituent Cell Heterogeneity Facilitate Electrical Conduction Disturbances in a Human Induced Pluripotent Stem Cell-Based Platform: An In vitro Disease Model of Atrial Arrhythmias. Front Physiol 2019; 10:818. [PMID: 31316396 PMCID: PMC6610482 DOI: 10.3389/fphys.2019.00818] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2019] [Accepted: 06/11/2019] [Indexed: 01/09/2023] Open
Abstract
Ectopic foci from pulmonary veins (PVs) comprise the main trigger associated with the initiation of atrial fibrillation (AF). An abrupt anatomical narrow-to-wide transition, modeled as in vitro geometrical patterning with similar configuration in the present study, is located at the junction of PVs and the left atrium (LA). Complex cellular composition, i.e., constituent cell heterogeneity, is also observed in PVs and the PVs-LA junction. High frequency triggers accompanied with anatomical irregularity and constituent cell heterogeneity provoke impaired conduction, a prerequisite for AF genesis. However, few experiments investigating the effects of these factors on electrophysiological properties using human-based cardiomyocytes (CMs) with atrial properties have been reported. The aim of the current study was to estimate whether geometrical patterning and constituent cell heterogeneity under high frequency stimuli undergo conduction disturbance utilizing an in vitro two-dimensional (2D) monolayer preparation consisting of atrial-like CMs derived from human induced pluripotent stem cells (hiPSCs) and atrial fibroblasts (Fbs). We induced hiPSCs into atrial-like CMs using a directed cardiac differentiation protocol with the addition of all-trans retinoic acid (ATRA). The atrial-like hiPSC-derived CMs (hiPSC-CMs) and atrial Fbs were transferred in defined ratios (CMs/Fbs: 100%/0% or 70%/30%) on manually fabricated plates with or without geometrical patterning imitating the PVs-LA junction. High frequency field stimulation emulating repetitive ectopic foci originated in PVs were delivered, and the electrical propagation was assessed by optical mapping. We generated high purity CMs with or without the ATRA application. ATRA-treated hiPSC-CMs exhibited significantly higher atrial-specific properties by immunofluorescence staining, gene expression patterns, and optical action potential parameters than those of ATRA-untreated hiPSC-CMs. Electrical stimuli at a higher frequency preferentially induced impaired electrical conduction on atrial-like hiPSC-CMs monolayer preparations with an abrupt geometrical transition than on those with uniform geometry. Additionally, the application of human atrial Fbs to the geometrically patterned atrial-like hiPSC-CMs tended to further deteriorate the integrity of electrical conduction compared with those using the atrial-like hiPSC-CM alone preparations. Thus, geometrical narrow-to-wide patterning under high frequency stimuli preferentially jeopardized electrical conduction within in vitro atrial-like hiPSC-CM monolayers. Constituent cell heterogeneity represented by atrial Fbs also contributed to the further deterioration of conduction stability.
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Affiliation(s)
- Hiroyuki Nakanishi
- Department of Cardiovascular Medicine, Graduate School of Medicine, Osaka University, Suita, Japan
| | - Jong-Kook Lee
- Department of Advanced Cardiovascular Regenerative Medicine, Graduate School of Medicine, Osaka University, Suita, Japan
| | - Keiko Miwa
- Department of Mechanical Engineering, Kyushu University, Fukuoka, Japan
| | - Kiyoshi Masuyama
- Department of Cardiovascular Medicine, Graduate School of Medicine, Osaka University, Suita, Japan
| | - Hideki Yasutake
- Department of Cardiovascular Medicine, Graduate School of Medicine, Osaka University, Suita, Japan
| | - Jun Li
- Department of Cardiovascular Medicine, Graduate School of Medicine, Osaka University, Suita, Japan
| | - Satoki Tomoyama
- Department of Cardiovascular Medicine, Graduate School of Medicine, Osaka University, Suita, Japan
| | - Yayoi Honda
- Preclinical Research Unit, Sumitomo Dainippon Pharma Co., Ltd., Osaka, Japan
| | - Jiro Deguchi
- Preclinical Research Unit, Sumitomo Dainippon Pharma Co., Ltd., Osaka, Japan
| | - Shinji Tsujimoto
- Regenerative & Cellular Medicine Office, Sumitomo Dainippon Pharma Co., Ltd., Osaka, Japan
| | - Kyoko Hidaka
- Department of Advanced Cardiovascular Regenerative Medicine, Graduate School of Medicine, Osaka University, Suita, Japan.,Center for Fundamental Education, The University of Kitakyushu, Kitakyushu, Japan
| | - Shigeru Miyagawa
- Department of Cardiovascular Surgery, Graduate School of Medicine, Osaka University, Suita, Japan
| | - Yoshiki Sawa
- Department of Cardiovascular Surgery, Graduate School of Medicine, Osaka University, Suita, Japan
| | - Issei Komuro
- Department of Cardiovascular Medicine, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - Yasushi Sakata
- Department of Cardiovascular Medicine, Graduate School of Medicine, Osaka University, Suita, Japan
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18
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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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19
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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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20
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Henry AD, MacQuaide N, Burton FL, Rankin AC, Rowan EG, Drummond RM. Spontaneous Ca 2+ transients in rat pulmonary vein cardiomyocytes are increased in frequency and become more synchronous following electrical stimulation. Cell Calcium 2018; 76:36-47. [PMID: 30253263 DOI: 10.1016/j.ceca.2018.09.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2018] [Revised: 08/09/2018] [Accepted: 09/02/2018] [Indexed: 12/13/2022]
Abstract
The pulmonary veins have an external sleeve of cardiomyocytes that are a widely recognised source of ectopic electrical activity that can lead to atrial fibrillation. Although the mechanisms behind this activity are currently unknown, changes in intracellular calcium (Ca2+) signalling are purported to play a role. Therefore, the intracellular Ca2+ concentration was monitored in the pulmonary vein using fluo-4 and epifluorescence microscopy. Electrical field stimulation evoked a synchronous rise in Ca2+ in neighbouring cardiomyocytes; asynchronous spontaneous Ca2+ transients between electrical stimuli were also present. Immediately following termination of electrical field stimulation at 3 Hz or greater, the frequency of the spontaneous Ca2+ transients was increased from 0.45 ± 0.06 Hz under basal conditions to between 0.59 ± 0.05 and 0.65 ± 0.06 Hz (P < 0.001). Increasing the extracellular Ca2+ concentration enhanced this effect, with the frequency of spontaneous Ca2+ transients increasing from 0.45 ± 0.05 Hz to between 0.75 ± 0.06 and 0.94 ± 0.09 Hz after electrical stimulation at 3 to 9 Hz (P < 0.001), and this was accompanied by a significant increase in the velocity of Ca2+ transients that manifested as waves. Moreover, in the presence of high extracellular Ca2+, the spontaneous Ca2+ transients occurred more synchronously in the initial few seconds following electrical stimulation. The ryanodine receptors, which are the source of spontaneous Ca2+ transients in pulmonary vein cardiomyocytes, were found to be arranged in a striated pattern in the cell interior, as well as along the periphery of cell. Furthermore, labelling the sarcolemma with di-4-ANEPPS showed that over 90% of pulmonary vein cardiomyocytes possessed T-tubules. These findings demonstrate that the frequency of spontaneous Ca2+ transients in the rat pulmonary vein are increased following higher rates of electrical stimulation and increasing the extracellular Ca2+ concentration.
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Affiliation(s)
- Alasdair D Henry
- Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, Glasgow, UK
| | - N MacQuaide
- Institute of Cardiovascular and Medical Sciences, College of Medical, Veterinary and Life Sciences, University of Glasgow, UK
| | - F L Burton
- Institute of Cardiovascular and Medical Sciences, College of Medical, Veterinary and Life Sciences, University of Glasgow, UK
| | - A C Rankin
- Institute of Cardiovascular and Medical Sciences, College of Medical, Veterinary and Life Sciences, University of Glasgow, UK
| | - E G Rowan
- Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, Glasgow, UK
| | - R M Drummond
- Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, Glasgow, UK.
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21
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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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22
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Structural heterogeneity of the rat pulmonary vein myocardium: consequences on intracellular calcium dynamics and arrhythmogenic potential. Sci Rep 2018; 8:3244. [PMID: 29459735 PMCID: PMC5818479 DOI: 10.1038/s41598-018-21671-9] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2017] [Accepted: 02/08/2018] [Indexed: 11/09/2022] Open
Abstract
Mechanisms underlying ectopic activity in the pulmonary vein (PV) which triggers paroxysmal atrial fibrillation are unknown. Although several studies have suggested that calcium signalling might be involved in these arrhythmias, little is known about calcium cycling in PV cardiomyocytes (CM). We found that individual PV CM showed a wide range of transverse tubular incidence and organization, going from their virtual absence, as described in atrial CM, to well transversally organised tubular systems, like in ventricular CM. These different types of CM were found in groups scattered throughout the tissue. The variability of the tubular system was associated with cell to cell heterogeneity of calcium channel (Cav1.2) localisation and, thereby, of Cav1.2-Ryanodine receptor coupling. This was responsible for multiple forms of PV CM calcium transient. Spontaneous calcium sparks and waves were not only more abundant in PV CM than in LA CM but also associated with a higher depolarising current. In conclusion, compared with either the atrium or the ventricle, PV myocardium presents marked structural and functional heterogeneity.
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Irie M, Tsuneoka Y, Shimobayashi M, Hasegawa N, Tanaka Y, Mochizuki S, Ichige S, Hamaguchi S, Namekata I, Tanaka H. Involvement of alpha- and beta-adrenoceptors in the automaticity of the isolated guinea pig pulmonary vein myocardium. J Pharmacol Sci 2017; 133:247-253. [PMID: 28410967 DOI: 10.1016/j.jphs.2017.03.003] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2016] [Revised: 03/10/2017] [Accepted: 03/14/2017] [Indexed: 01/12/2023] Open
Abstract
We examined the involvement of adrenoceptors in the automaticity of the pulmonary vein myocardium, which probably plays a crucial role in the generation of atrial fibrillation. The automatic activity of the myocardium in guinea pig pulmonary vein tissue preparations were monitored by contractile force or membrane potential measurement. In quiescent preparations, application of noradrenaline induced an automatic activity. The firing frequency was reduced by prazosin or atenolol. Methoxamine induced an automatic activity of low frequency, which was accelerated by further application of isoproterenol. In preparations driven at a constant frequency, noradrenaline, in the presence of atenolol, caused a depolarizing shift of the resting membrane potential and an increase in the slope of the diastolic depolarization. In contrast, in the presence of prazosin, noradrenaline had no effect on the slope, but caused acceleration of the late repolarization and a hyperpolarizing shift of the maximum diastolic potential. At clinically relevant concentrations, carvedilol significantly inhibited the noradrenaline-induced activity but bisoprolol did not. It was concluded that α1- and β1-adrenoceptor stimulation enhance automaticity through different mechanisms in the guinea pig pulmonary vein myocardium. Dual blockade of these adrenoceptors appears to be effective for suppressing noradrenaline-induced pulmonary vein automaticity and probably atrial fibrillation.
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Affiliation(s)
- Masahiko Irie
- Department of Pharmacology, Faculty of Pharmaceutical Sciences, Toho University, Funabashi, Chiba 274-8510, Japan
| | - Yayoi Tsuneoka
- Department of Pharmacology, Faculty of Pharmaceutical Sciences, Toho University, Funabashi, Chiba 274-8510, Japan; Laboratory of Pharmacology, Faculty of Pharmaceutical Sciences, Tokyo University of Science, Noda, Chiba 278-8510, Japan
| | - Mariko Shimobayashi
- Department of Pharmacology, Faculty of Pharmaceutical Sciences, Toho University, Funabashi, Chiba 274-8510, Japan
| | - Nao Hasegawa
- 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
| | - Soh Mochizuki
- Department of Pharmacology, Faculty of Pharmaceutical Sciences, Toho University, Funabashi, Chiba 274-8510, Japan
| | - Sho Ichige
- Department of Pharmacology, 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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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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Hamaguchi S, Tsuneoka Y, Tanaka A, Irie M, Tsuruta M, Nakayama T, Namekata I, Nada M, Aimoto M, Takahara A, Tanaka H. Manifestation of automaticity in the pulmonary-vein myocardium of rats with abdominal aorto-venocaval shunt. J Pharmacol Sci 2015; 128:212-5. [PMID: 26318676 DOI: 10.1016/j.jphs.2015.07.041] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2015] [Revised: 07/18/2015] [Accepted: 07/30/2015] [Indexed: 11/17/2022] Open
Abstract
Effect of abdominal aorto-venocaval shunt (AVS) on the automaticity of the pulmonary-vein myocardium was studied in the rat. Spontaneous electrical activity was observed in one third of the isolated pulmonary-vein preparations from the AVS rats, but scarcely in those from sham-operated rats; the activity was induced by tertiapin and suppressed by carbachol or chelation of intracellular Ca(2+). The evoked action potentials in AVS rats had less negative resting membrane potential and longer action potential duration than those in sham-operated rats. These results suggest that the automaticity of the rat pulmonary-vein myocardium is manifested under chronic volume overload.
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Affiliation(s)
- Shogo Hamaguchi
- Department of Pharmacology, Faculty of Pharmaceutical Sciences, Toho University, Funabashi, Chiba 274-8510, Japan.
| | - 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
| | - Ayumi Tanaka
- Department of Pharmacology, Faculty of Pharmaceutical Sciences, Toho University, Funabashi, Chiba 274-8510, Japan
| | - Masahiko Irie
- Department of Pharmacology, Faculty of Pharmaceutical Sciences, Toho University, Funabashi, Chiba 274-8510, Japan
| | - Masato Tsuruta
- Department of Pharmacology, Faculty of Pharmaceutical Sciences, Toho University, Funabashi, Chiba 274-8510, Japan
| | - Takahiro Nakayama
- 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
| | - Mizuki Nada
- Department of Pharmacology and Therapeutics, Faculty of Pharmaceutical Sciences, Toho University, Funabashi, Chiba 274-8510, Japan
| | - Megumi Aimoto
- Department of Pharmacology and Therapeutics, Faculty of Pharmaceutical Sciences, Toho University, Funabashi, Chiba 274-8510, Japan
| | - Akira Takahara
- Department of Pharmacology and Therapeutics, 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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26
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Wolke C, Bukowska A, Goette A, Lendeckel U. Redox control of cardiac remodeling in atrial fibrillation. Biochim Biophys Acta Gen Subj 2014; 1850:1555-65. [PMID: 25513966 DOI: 10.1016/j.bbagen.2014.12.012] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2014] [Revised: 11/04/2014] [Accepted: 12/09/2014] [Indexed: 01/08/2023]
Abstract
BACKGROUND Atrial fibrillation (AF) is the most common arrhythmia in clinical practice and is a potential cause of thromboembolic events. AF induces significant changes in the electrophysiological properties of atrial myocytes and causes alterations in the structure, metabolism, and function of the atrial tissue. The molecular basis for the development of structural atrial remodeling of fibrillating human atria is still not fully understood. However, increased production of reactive oxygen or nitrogen species (ROS/RNS) and the activation of specific redox-sensitive signaling pathways observed both in patients with and animal models of AF are supposed to contribute to development, progression and self-perpetuation of AF. SCOPE OF REVIEW The present review summarizes the sources and targets of ROS/RNS in the setting of AF and focuses on key redox-sensitive signaling pathways that are implicated in the pathogenesis of AF and function either to aggravate or protect from disease. MAJOR CONCLUSIONS NADPH oxidases and various mitochondrial monooxygenases are major sources of ROS during AF. Besides direct oxidative modification of e.g. ion channels and ion handling proteins that are crucially involved in action potential generation and duration, AF leads to the reversible activation of redox-sensitive signaling pathways mediated by activation of redox-regulated proteins including Nrf2, NF-κB, and CaMKII. Both processes are recognized to contribute to the formation of a substrate for AF and, thus, to increase AF inducibility and duration. GENERAL SIGNIFICANCE AF is a prevalent disease and due to the current demographic developments its socio-economic relevance will further increase. Improving our understanding of the role that ROS and redox-related (patho)-mechanisms play in the development and progression of AF may allow the development of a targeted therapy for AF that surpasses the efficacy of previous general anti-oxidative strategies. This article is part of a Special Issue entitled Redox regulation of differentiation and de-differentiation.
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Affiliation(s)
- Carmen Wolke
- Institute of Medical Biochemistry and Molecular Biology, University Medicine Greifswald, D-17487 Greifswald, Germany
| | - Alicja Bukowska
- EUTRAF Working Group: Molecular Electrophysiology, University Hospital Magdeburg, D-39120 Magdeburg, Germany
| | - Andreas Goette
- EUTRAF Working Group: Molecular Electrophysiology, University Hospital Magdeburg, D-39120 Magdeburg, Germany; Department of Cardiology and Intensive Care Medicine, St. Vincenz-Hospital, D-33098 Paderborn, Germany
| | - Uwe Lendeckel
- Institute of Medical Biochemistry and Molecular Biology, University Medicine Greifswald, D-17487 Greifswald, Germany.
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MALÉCOT CLAIREO, BREDELOUX PIERRE, FINDLAY IAN, MAUPOIL VÉRONIQUE. A TTX-Sensitive Resting Na+
Permeability Contributes to the Catecholaminergic Automatic Activity in Rat Pulmonary Vein. J Cardiovasc Electrophysiol 2014; 26:311-9. [DOI: 10.1111/jce.12572] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/28/2014] [Revised: 09/20/2014] [Accepted: 10/16/2014] [Indexed: 11/30/2022]
Affiliation(s)
- CLAIRE O. MALÉCOT
- CNRS ERL 7368; Laboratoire Signalisation et Transports Ioniques Membranaires; Universités de Poitiers et François-Rabelais de Tours; France
- Groupe Physiologie des Cellules Cardiaques et Vasculaires; Université François-Rabelais; Tours France
| | - PIERRE BREDELOUX
- Groupe Physiologie des Cellules Cardiaques et Vasculaires; Université François-Rabelais; Tours France
| | - IAN FINDLAY
- CNRS ERL 7368; Laboratoire Signalisation et Transports Ioniques Membranaires; Universités de Poitiers et François-Rabelais de Tours; France
- Groupe Physiologie des Cellules Cardiaques et Vasculaires; Université François-Rabelais; Tours France
| | - VÉRONIQUE MAUPOIL
- CNRS ERL 7368; Laboratoire Signalisation et Transports Ioniques Membranaires; Universités de Poitiers et François-Rabelais de Tours; France
- Groupe Physiologie des Cellules Cardiaques et Vasculaires; Université François-Rabelais; Tours France
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28
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Caldwell JL, Smith CER, Taylor RF, Kitmitto A, Eisner DA, Dibb KM, Trafford AW. Dependence of cardiac transverse tubules on the BAR domain protein amphiphysin II (BIN-1). Circ Res 2014; 115:986-96. [PMID: 25332206 DOI: 10.1161/circresaha.116.303448] [Citation(s) in RCA: 96] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
RATIONALE Transverse tubules (t-tubules) regulate cardiac excitation-contraction coupling and exhibit interchamber and interspecies differences in expression. In cardiac disease, t-tubule loss occurs and affects the systolic calcium transient. However, the mechanisms controlling t-tubule maintenance and whether these factors differ between species, cardiac chambers, and in a disease setting remain unclear. OBJECTIVE To determine the role of the Bin/Amphiphysin/Rvs domain protein amphiphysin II (AmpII) in regulating t-tubule maintenance and the systolic calcium transient. METHODS AND RESULTS T-tubule density was assessed by di-4-ANEPPS, FM4-64 or WGA staining using confocal microscopy. In rat, ferret, and sheep hearts t-tubule density and AmpII protein levels were lower in the atrium than in the ventricle. Heart failure (HF) was induced in sheep using right ventricular tachypacing and ferrets by ascending aortic coarctation. In both HF models, AmpII protein and t-tubule density were decreased in the ventricles. In the sheep, atrial t-tubules were also lost in HF and AmpII levels decreased. Conversely, junctophilin 2 levels did not show interchamber differences in the rat and ferret nor did they change in HF in the sheep or ferret. In addition, in rat atrial and sheep HF atrial cells where t-tubules were absent, junctophilin 2 had sarcomeric intracellular distribution. Small interfering RNA-induced knockdown of AmpII protein reduced t-tubule density, calcium transient amplitude, and the synchrony of the systolic calcium transient. CONCLUSIONS AmpII is intricately involved in t-tubule maintenance. Reducing AmpII protein decreases t-tubule density, reduces the amplitude, and increases the heterogeneity of the systolic calcium transient.
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Affiliation(s)
- Jessica L Caldwell
- From the Unit of Cardiac Physiology and Cardiac Biophysics Group, Institute of Cardiovascular Sciences, Manchester Academic Health Science Centre, University of Manchester, Manchester, United Kingdom
| | - Charlotte E R Smith
- From the Unit of Cardiac Physiology and Cardiac Biophysics Group, Institute of Cardiovascular Sciences, Manchester Academic Health Science Centre, University of Manchester, Manchester, United Kingdom
| | - Rebecca F Taylor
- From the Unit of Cardiac Physiology and Cardiac Biophysics Group, Institute of Cardiovascular Sciences, Manchester Academic Health Science Centre, University of Manchester, Manchester, United Kingdom
| | - Ashraf Kitmitto
- From the Unit of Cardiac Physiology and Cardiac Biophysics Group, Institute of Cardiovascular Sciences, Manchester Academic Health Science Centre, University of Manchester, Manchester, United Kingdom
| | - David A Eisner
- From the Unit of Cardiac Physiology and Cardiac Biophysics Group, Institute of Cardiovascular Sciences, Manchester Academic Health Science Centre, University of Manchester, Manchester, United Kingdom
| | - Katharine M Dibb
- From the Unit of Cardiac Physiology and Cardiac Biophysics Group, Institute of Cardiovascular Sciences, Manchester Academic Health Science Centre, University of Manchester, Manchester, United Kingdom
| | - Andrew W Trafford
- From the Unit of Cardiac Physiology and Cardiac Biophysics Group, Institute of Cardiovascular Sciences, Manchester Academic Health Science Centre, University of Manchester, Manchester, United Kingdom.
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Rietdorf K, Bootman MD, Sanderson MJ. Spontaneous, pro-arrhythmic calcium signals disrupt electrical pacing in mouse pulmonary vein sleeve cells. PLoS One 2014; 9:e88649. [PMID: 24586364 PMCID: PMC3930634 DOI: 10.1371/journal.pone.0088649] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2013] [Accepted: 01/08/2014] [Indexed: 11/18/2022] Open
Abstract
The pulmonary vein, which returns oxygenated blood to the left atrium, is ensheathed by a population of unique, myocyte-like cells called pulmonary vein sleeve cells (PVCs). These cells autonomously generate action potentials that propagate into the left atrial chamber and cause arrhythmias resulting in atrial fibrillation; the most common, often sustained, form of cardiac arrhythmia. In mice, PVCs extend along the pulmonary vein into the lungs, and are accessible in a lung slice preparation. We exploited this model to study how aberrant Ca(2+) signaling alters the ability of PVC networks to follow electrical pacing. Cellular responses were investigated using real-time 2-photon imaging of lung slices loaded with a Ca(2+)-sensitive fluorescent indicator (Ca(2+) measurements) and phase contrast microscopy (contraction measurements). PVCs displayed global Ca(2+) signals and coordinated contraction in response to electrical field stimulation (EFS). The effects of EFS relied on both Ca(2+) influx and Ca(2+) release, and could be inhibited by nifedipine, ryanodine or caffeine. Moreover, PVCs had a high propensity to show spontaneous Ca(2+) signals that arose via stochastic activation of ryanodine receptors (RyRs). The ability of electrical pacing to entrain Ca(2+) signals and contractile responses was dramatically influenced by inherent spontaneous Ca(2+) activity. In PVCs with relatively low spontaneous Ca(2+) activity (<1 Hz), entrainment with electrical pacing was good. However, in PVCs with higher frequencies of spontaneous Ca(2+) activity (>1.5 Hz), electrical pacing was less effective; PVCs became unpaced, only partially-paced or displayed alternans. Because spontaneous Ca(2+) activity varied between cells, neighboring PVCs often had different responses to electrical pacing. Our data indicate that the ability of PVCs to respond to electrical stimulation depends on their intrinsic Ca(2+) cycling properties. Heterogeneous spontaneous Ca(2+) activity arising from stochastic RyR opening can disengage them from sinus rhythm and lead to autonomous, pro-arrhythmic activity.
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Affiliation(s)
- Katja Rietdorf
- Department of Microbiology and Physiological Systems, University of Massachusetts, Medical School, Worcester, Massachusetts, United States of America
- Department of Life, Health and Chemical Science, The Open University, Milton Keynes, United Kingdom
- * E-mail:
| | - Martin D. Bootman
- Department of Life, Health and Chemical Science, The Open University, Milton Keynes, United Kingdom
- Signalling Programme, The Babraham Institute, Cambridge, United Kingdom
| | - Michael J. Sanderson
- Department of Microbiology and Physiological Systems, University of Massachusetts, Medical School, Worcester, Massachusetts, United States of America
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30
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Pathological impact of hyperpolarization-activated chloride current peculiar to rat pulmonary vein cardiomyocytes. J Mol Cell Cardiol 2013; 66:53-62. [PMID: 24239603 DOI: 10.1016/j.yjmcc.2013.11.002] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/27/2013] [Revised: 10/28/2013] [Accepted: 11/04/2013] [Indexed: 01/10/2023]
Abstract
Pulmonary veins (PVs) are believed to be a crucial origin of atrial fibrillation. We recently reported that rat PV cardiomyocytes exhibit arrhythmogenic automaticity in response to norepinephrine. Herein, we further characterized the electrophysiological properties underlying the potential arrhythmogenicity of PV cardiomyocytes. Patch clamping studies revealed a time dependent hyperpolarization-activated inward current in rat PV cardiomyocytes, but not in left atrial (LA) myocytes. The current was Cs(+) resistant, and was not affected by removal of external Na(+) or K(+). The current was inhibited with Cd(2+), and the reversal potential was sensitive to changes in [Cl(-)] on either side of the membrane in a manner consistent with a Cl(-) selective channel. Cl(-) channel blockers attenuated the current, and slowed or completely inhibited the norepinephrine-induced automaticity. The biophysical properties of the hyperpolarization-activated Cl(-) current in rat PVs were different from those of ClC-2 currents previously reported: (i) the voltage-dependent activation of the Cl(-) current in rat PVs was shifted to negative potentials as [Cl(-)]i increased, (ii) the Cl(-) current was enhanced by extracellular acidification, and (iii) extracellular hyper-osmotic stress increased the current, whereas hypo-osmotic cell swelling suppressed the current. qPCR analysis revealed negligible ClC-2 mRNA expression in the rat PV. These findings suggest that rat PV cardiomyocytes possess a peculiar voltage-dependent Cl(-) channel, and that the channel may play a functional role in norepinephrine-induced automaticity.
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The mitochondrial Na+-Ca2+ exchanger, NCLX, regulates automaticity of HL-1 cardiomyocytes. Sci Rep 2013; 3:2766. [PMID: 24067497 PMCID: PMC3783885 DOI: 10.1038/srep02766] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2013] [Accepted: 09/05/2013] [Indexed: 01/10/2023] Open
Abstract
Mitochondrial Ca2+ is known to change dynamically, regulating mitochondrial as well as cellular functions such as energy metabolism and apoptosis. The NCLX gene encodes the mitochondrial Na+-Ca2+ exchanger (NCXmit), a Ca2+ extrusion system in mitochondria. Here we report that the NCLX regulates automaticity of the HL-1 cardiomyocytes. NCLX knockdown using siRNA resulted in the marked prolongation of the cycle length of spontaneous Ca2+ oscillation and action potential generation. The upstrokes of action potential and Ca2+ transient were markedly slower, and sarcoplasmic reticulum (SR) Ca2+ handling were compromised in the NCLX knockdown cells. Analyses using a mathematical model of HL-1 cardiomyocytes demonstrated that blocking NCXmit reduced the SR Ca2+ content to slow spontaneous SR Ca2+ leak, which is a trigger of automaticity. We propose that NCLX is a novel molecule to regulate automaticity of cardiomyocytes via modulating SR Ca2+ handling.
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32
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Namekata I, Tsuneoka Y, Tanaka H. Electrophysiological and Pharmacological Properties of the Pulmonary Vein Myocardium. Biol Pharm Bull 2013; 36:2-7. [DOI: 10.1248/bpb.b212020] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Affiliation(s)
- Iyuki Namekata
- Department of Pharmacology, Faculty of Pharmaceutical Sciences, Toho University
| | - Yayoi Tsuneoka
- Department of Pharmacology, Faculty of Pharmaceutical Sciences, Toho University
| | - Hikaru Tanaka
- Department of Pharmacology, Faculty of Pharmaceutical Sciences, Toho University
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33
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Liu Q, Bian W, Shi H, Fan L, Shuang S, Dong C, Choi MMF. A novel ratiometric emission probe for Ca2+in living cells. Org Biomol Chem 2013. [DOI: 10.1039/c2ob26888d] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
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34
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Tsuneoka Y, Kobayashi Y, Honda Y, Namekata I, Tanaka H. Electrical activity of the mouse pulmonary vein myocardium. J Pharmacol Sci 2012; 119:287-92. [PMID: 22785034 DOI: 10.1254/jphs.12062sc] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022] Open
Abstract
We recorded the electrical activity from the myocardial layer of isolated mouse pulmonary veins with the glass microelectrode technique. Spontaneous electrical activity was observed in about half of the preparations, which appeared either as constant firing or as repetitive bursts. Noradrenaline enhanced, while acetylcholine reduced, automatic activity. The action potentials evoked in quiescent preparations showed a resting membrane potential less negative than the atria and an extremely rapid early repolarization followed by a late plateau. The present study revealed that the mouse pulmonary vein myocardium shows diverse electrical activity, which is influenced by autonomic neurotransmitters.
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Affiliation(s)
- Yayoi Tsuneoka
- Department of Pharmacology, Toho University Faculty of Pharmaceutical Sciences, Funabashi, Chiba 274-8510, Japan
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