Document Detail

Heat-stress responses modulate beta-adrenergic agonist and angiotensin II effects on the arrhythmogenesis of pulmonary vein cardiomyocytes.
MedLine Citation:
PMID:  20662989     Owner:  NLM     Status:  In-Process    
INTRODUCTION: Heat stress-induced responses reduce the occurrence of atrial fibrillation (AF). Pulmonary vein (PV) cardiomyocytes with pacemaker activity play a critical role in the pathophysiology of AF. In this study, we examined whether heat-stress responses alter the electrophysiological characteristics of PV cardiomyocytes and protect the PV against angiotensin II- or isoproterenol-induced arrhythmogenesis.
METHODS AND RESULTS: We used whole-cell patch clamp techniques to investigate the spontaneous activity and ionic currents in single isolated rabbit PV pacemaker cardiomyocytes with or without (control) exposure to heat stress (43°C, 15 minutes) 5 ± 1 hours before the experiments. Compared to control cardiomyocytes, heat-stressed PV cardiomyocytes had slower beating rates. Heat-stressed PV cardiomyocytes had larger L-type calcium currents, transient outward currents, smaller inward rectifier potassium currents, but similar sodium-calcium exchanger currents. Additionally, heat-stressed PV cardiomyocytes had a lower incidence of pacemaker currents than control PV cardiomyocytes. Moreover, isoproterenol increased the beating rate of control cardiomyocytes but not heat-stressed PV cardiomyocytes. Similarly, angiotensin II also increased the beating rate of control cardiomyocytes, but not heat-stressed PV cardiomyocytes, in association with decreased expression of the angiotensin II type 1 receptor.
CONCLUSION: Heat-stress responses altered the electrophysiological characteristics of PV cardiomyocytes and attenuated the effects of isoproterenol and angiotensin II on PV arrhythmogenesis, which may play a role in the protective potential of heat-stress responses.
Chen-Chuan Cheng; Chun-Feng Huang; Yao-Chang Chen; Yung-Kuo Lin; Yu-Hsun Kao; Yi-Jen Chen; Shih-Ann Chen
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Journal of cardiovascular electrophysiology     Volume:  22     ISSN:  1540-8167     ISO Abbreviation:  J. Cardiovasc. Electrophysiol.     Publication Date:  2011 Feb 
Date Detail:
Created Date:  2011-02-14     Completed Date:  -     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  9010756     Medline TA:  J Cardiovasc Electrophysiol     Country:  United States    
Other Details:
Languages:  eng     Pagination:  183-90     Citation Subset:  IM    
Copyright Information:
© 2010 Wiley Periodicals, Inc.
Division of Cardiology, Chi-Mei Medical Center, Tainan, Taiwan.
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Comment In:
J Cardiovasc Electrophysiol. 2011 Feb;22(2):191-2   [PMID:  20807273 ]

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