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Sarcoplasmic reticulum, calcium waves and myometrial signalling
1Department of Obstetrics and Gynecology, Medical University of South Carolina, Charleston 29425, USA.
Novartis Foundation Symposium
|August 8, 2002
Summary
Intracellular calcium (Ca2+) waves in uterine smooth muscle are driven by the sarcoplasmic reticulum. Their propagation speed is limited by cytoplasmic calcium diffusion.
Area of Science:
- Cellular Biology
- Muscle Physiology
- Biophysics
Background:
- Calcium (Ca2+) waves are coordinated intracellular rises in free Ca2+.
- These waves function in cellular signal integration and information processing.
- This review focuses on intracellular Ca2+ waves in uterine smooth muscle and their link to the sarcoplasmic reticulum (SR).
Purpose of the Study:
- To review the mechanisms of intracellular Ca2+ waves in uterine smooth muscle.
- To explore the relationship between Ca2+ waves and the sarcoplasmic reticulum (SR).
- To identify the rate-limiting step in Ca2+ wave propagation.
Main Methods:
- Review of existing literature on intracellular Ca2+ waves.
- Analysis of Ca2+ wave propagation mechanisms in uterine myocytes.
- Measurement of wave speeds using time-lapse imaging of Ca2+-dependent fluorescent dyes.
Main Results:
- Ca2+ wave speeds are independent of extracellular Ca2+, indicating the SR as the Ca2+ source.
- Wave propagation involves SR Ca2+ release via InsP3 receptors, Ca2+-induced Ca2+ release, or both.
- Cytoplasmic Ca2+ diffusion is the rate-determining step for wave propagation.
Conclusions:
- Intracellular Ca2+ waves in uterine myocytes are primarily mediated by SR Ca2+ release.
- Cytoplasmic diffusion limits the speed of Ca2+ wave propagation.
- Ca2+ waves influence capacitative Ca2+ entry, linking cytoplasmic and subplasmalemmal Ca2+ levels.