Heat stress responses modulate calcium regulations and electrophysiological characteristics in atrial myocytes

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

Research output: Contribution to journalArticle

20 Citations (Scopus)

Abstract

Heat stress-induced responses change the ionic currents and calcium homeostasis. However, the molecular insights into the heat stress responses on calcium homeostasis remain unclear. The purposes of this study were to examine the mechanisms of heat stress responses on calcium handling and electrophysiological characteristics in atrial myocytes. We used indo-1 fluorimetric ratio technique and whole-cell patch clamp to investigate the intracellular calcium, action potentials, and ionic currents in isolated rabbit single atrial cardiomyocytes with or without (control) exposure to heat stress (43 °C, 15 min) 5 ± 1 h before experiments. The expressions of sarcoplasmic reticulum ATPase (SERCA2a), and Na+-Ca2+ exchanger (NCX) in the control and heat stress-treated atrial myocytes were evaluated by Western blot and real-time PCR. As compared with control myocytes, the heat stress-treated myocytes had larger sarcoplasmic reticulum calcium content and larger intracellular calcium transient with a shorter decay portion. Heat stress-treated myocytes also had larger L-type calcium currents, transient outward potassium currents, but smaller NCX currents. Heat stress responses increased the protein expressions, SERCA2a, NCX, and heat shock protein. However, heat stress responses did not change the RNA expression of SERCA2a and NCX. In conclusion, heat stress responses change calcium handling through protein but not RNA regulation.

Original languageEnglish
Pages (from-to)781-788
Number of pages8
JournalJournal of Molecular and Cellular Cardiology
Volume48
Issue number4
DOIs
Publication statusPublished - Apr 2010

Keywords

  • Atrial fibrillation
  • Calcium homeostasis
  • Electrophysiology
  • Heat stress
  • Ionic currents

ASJC Scopus subject areas

  • Molecular Biology
  • Cardiology and Cardiovascular Medicine

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