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Paper Abstract and Keywords
Presentation 2010-03-11 11:05
Changes in the concentrations of Ca2+ and Mg2+ induced by high-frequency electrical stimulation in adult rat cardiomyocytes.
Hiroyuki Igarashi, Yusuke Mizutani, Sadahiro Iwabuchi, Daisuke Matsuyama, Koichi Kawahara (Hokkaido Univ.) MBE2009-123
Abstract (in Japanese) (See Japanese page) 
(in English) Ventricular fibrillation (VF) and reentrant ventricular tachycardia (VT) are the major immediate causes of sudden cardiac death. Whereas VT is considered a rapid but well organized process, VF has been described as turbulent cardiac electrical activity, resulting from the random and aperiodic propagation of multiple independent wavelets throughout the cardiac muscle. Clinical studies have shown that VF is almost always preceded by VT of variable duration, from a few to many beats. However, the manner in which VT converts to VF, or vice versa is not yet fully understood despite more than a century of intensive study. We have previously demonstrated that the perfusion of isolated hearts with ruthenium red (RR), a blocker of the mitochondrial Ca2+ uniporter, converts pacing-induced sustained VF to VT. In addition, we have also demonstrated that the perfusion of isolated rat hearts with RR during sustained VF results in the close balance between myocardial energy supply and demand, suggesting that the balance was lost during VF, leading to the significant decrease of cellular ATP in the myocardium during VF. In this study, we investigated whether high-frequency electrical stimulation affected the intracellular concentration of Ca2+ and Mg2+ dynamics in isolated adult rat cardiomyocytes. The present study revealed that the persistent high-frequency stimulation resulted in the collapse in an ionic homeostasis in cardiomyocytes. In addition, the intracellular concentration of Mg2+ increased significantly in association with the high-frequency stimulation –induced hypercontraction, suggesting that the myocardial ATP content was markedly reduced during the stimulation.
Keyword (in Japanese) (See Japanese page) 
(in English) cardiomyocytes / electrical stimulation / contraction / [Ca2+]i / [Mg2+]i / / /  
Reference Info. IEICE Tech. Rep., vol. 109, no. 460, MBE2009-123, pp. 123-125, March 2010.
Paper # MBE2009-123 
Date of Issue 2010-03-02 (MBE) 
ISSN Print edition: ISSN 0913-5685  Online edition: ISSN 2432-6380
All rights are reserved and no part of this publication may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopy, recording, or any information storage and retrieval system, without permission in writing from the publisher. Notwithstanding, instructors are permitted to photocopy isolated articles for noncommercial classroom use without fee. (License No.: 10GA0019/12GB0052/13GB0056/17GB0034/18GB0034)
Download PDF MBE2009-123

Conference Information
Committee NC MBE  
Conference Date 2010-03-09 - 2010-03-11 
Place (in Japanese) (See Japanese page) 
Place (in English) Tamagawa University 
Topics (in Japanese) (See Japanese page) 
Topics (in English) General 
Paper Information
Registration To MBE 
Conference Code 2010-03-NC-MBE 
Language Japanese 
Title (in Japanese) (See Japanese page) 
Sub Title (in Japanese) (See Japanese page) 
Title (in English) Changes in the concentrations of Ca2+ and Mg2+ induced by high-frequency electrical stimulation in adult rat cardiomyocytes. 
Sub Title (in English)  
Keyword(1) cardiomyocytes  
Keyword(2) electrical stimulation  
Keyword(3) contraction  
Keyword(4) [Ca2+]i  
Keyword(5) [Mg2+]i  
1st Author's Name Hiroyuki Igarashi  
1st Author's Affiliation Hokkaido University (Hokkaido Univ.)
2nd Author's Name Yusuke Mizutani  
2nd Author's Affiliation Hokkaido University (Hokkaido Univ.)
3rd Author's Name Sadahiro Iwabuchi  
3rd Author's Affiliation Hokkaido University (Hokkaido Univ.)
4th Author's Name Daisuke Matsuyama  
4th Author's Affiliation Hokkaido University (Hokkaido Univ.)
5th Author's Name Koichi Kawahara  
5th Author's Affiliation Hokkaido University (Hokkaido Univ.)
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Date Time 2010-03-11 11:05:00 
Presentation Time 25 
Registration for MBE 
Paper # IEICE-MBE2009-123 
Volume (vol) IEICE-109 
Number (no) no.460 
Page pp.123-125 
#Pages IEICE-3 
Date of Issue IEICE-MBE-2010-03-02 

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