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 language | English (US) |
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Pages (from-to) | 31-37 |
Number of pages | 7 |
Journal | Science in China, Series C: Life Sciences |
Volume | 47 |
Issue number | 1 |
DOIs | |
State | Published - Jan 2004 |
Externally published | Yes |
Keywords
- Ca sparks
- Cardiac myocytes
- Confocal microscopy
- L-type Ca channels
ASJC Scopus subject areas
- General Biochemistry, Genetics and Molecular Biology
- General Environmental Science
- General Agricultural and Biological Sciences