Heat-stress responses modulate beta-adrenergic agonist and angiotensin II effects on the arrhythmogenesis of pulmonary vein cardiomyocytes

Chen Chuan Cheng, Chun Feng Huang, Yao Chang Chen, Yung Kuo Lin, Yu Hsun Kao, Yi Jen Chen, Shih Ann Chen

Research output: Contribution to journalArticle

3 Citations (Scopus)

Abstract

Effect of Heat Stress on Pulmonary Vein Cardiomyocytes. 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.

Original languageEnglish
Pages (from-to)183-190
Number of pages8
JournalJournal of Cardiovascular Electrophysiology
Volume22
Issue number2
DOIs
Publication statusPublished - Feb 2011

Keywords

  • angiotensin II
  • atrial fibrillation
  • heat stress
  • isoproterenol
  • pulmonary vein

ASJC Scopus subject areas

  • Cardiology and Cardiovascular Medicine
  • Physiology (medical)

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