Contribution of spontaneous L-type Ca2+ channel activation to the genesis of Ca2+ sparks in resting cardiac myocytes

Guangqin Zhang, Yu Fu, Dongmei Yang, Xuemei Hao, Shuhua Bai, Yiqun Tang, Edward G. Lakatta, Caihong Wu, Heping Cheng

Research output: Contribution to journalArticlepeer-review

Abstract

Ca2+ sparks are the elementary events of intracellular Ca 2+ release from the sarcoplasmic reticulum in cardiac myocytes. In order to investigate whether spontaneous L-type Ca2+ channel activation contributes to the genesis of spontaneous Ca2+ sparks, we used confocal laser scanning microscopy and fluo-4 to visualize local Ca 2+ sparks in intact rat ventricular myocytes. In the presence of 0.2 mmol/L CdCI2 which inhibits spontaneous L-type Ca2+ channel activation, the rate of occurrence of spontaneous Ca2+ sparks was halved from 4.20 to 2.04 events/(100 μm • s), with temporal and spatial properties of individual Ca2+ sparks unchanged. Analysis of the Cd2+-sensitive spark production revealed an open probability of ~10 -5 for L-type channels at the rest membrane potentials (-80 mV). Thus, infrequent and stochastic openings of sarcolemmal L-type Ca2+ channels in resting heart cells contribute significantly to the production of spontaneous Ca2+ sparks.

Original languageEnglish (US)
Pages (from-to)31-37
Number of pages7
JournalScience in China, Series C: Life Sciences
Volume47
Issue number1
DOIs
StatePublished - Jan 2004
Externally publishedYes

Keywords

  • Ca sparks
  • Cardiac myocytes
  • Confocal microscopy
  • L-type Ca channels

ASJC Scopus subject areas

  • Biochemistry, Genetics and Molecular Biology(all)
  • Environmental Science(all)
  • Agricultural and Biological Sciences(all)

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