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Abnormal calcium "sparks" in cardiomyocytes of post-myocardial infarction heart

Kai Huang1, Dan Huang, Shengquan Fu

  • 1Department of Cardiovascular Disease, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China. huangkai1@yahoo.com

Journal of Huazhong University of Science and Technology. Medical Sciences = Hua Zhong Ke Ji Da Xue Xue Bao. Yi Xue Ying De Wen Ban = Huazhong Keji Daxue Xuebao. Yixue Yingdewen Ban
|August 16, 2008
PubMed

Insights

Reduced L-type calcium channel activity in heart cells after myocardial infarction (MI) impairs calcium handling and leads to contractile dysfunction. This study reveals abnormal expression of key calcium channel subunits contributes to this early-stage damage.

Area of Science:

  • Cardiology
  • Molecular Biology
  • Physiology

Background:

  • Ischemic cardiomyopathy leads to contractile dysfunction due to impaired calcium handling.
  • Decreased calcium-induced calcium release (CICR) is a key factor in myocardial dysfunction post-ischemia.

Purpose of the Study:

  • To investigate the electrophysiological properties of L-type calcium channels in post-myocardial infarction (MI) rat myocardium.
  • To determine the expression levels of L-type calcium channel subunits in ischemic heart remodeling.

Main Methods:

  • Established an ischemic heart remodeling model in Sprague-Dawley rats.
  • Utilized realtime RT-PCR to quantify calcium channel subunit gene expression.
  • Employed whole-cell patch clamp technique to record L-type calcium channel currents (ICaL).

Main Results:

  • L-type calcium channel agonist Bayk 8644 significantly decreased CICR in post-MI cardiomyocytes.
  • A marked reduction in ICaL amplitude and a negative shift in inactivation curves were observed in post-MI cardiomyocytes.
  • Significant downregulation of alpha1c and beta2c L-type calcium channel subunit mRNA was found in post-MI rat ventricles.

Conclusions:

  • Abnormal expression of L-type calcium channel subunits contributes to decreased ICaL in early ischemic remodeling.
  • Reduced ICaL and impaired CICR in cardiomyocytes lead to myocardial contractile dysfunction post-MI.

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