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Mechanical Stimulation-induced Calcium Wave Propagation in Cell Monolayers: The Example of Bovine Corneal Endothelial Cells
Published on: July 16, 2013
Ca2+ signalling and membrane current activated by cADPr in starfish oocytes
1Laboratory of Cell Biology, Stazione Zoologica Anton Dohrn, Villa Comunale, 80121 Naples, Italy.
Pflugers Archiv : European Journal of Physiology
|May 21, 2003
Summary
Cyclic ADP-ribose (cADPr) triggers calcium waves in starfish oocytes by releasing calcium from ryanodine receptors. This calcium release then activates a cation current, but does not contribute to the overall calcium increase.
Area of Science:
- Cellular Biology
- Biochemistry
- Physiology
Background:
- Cyclic ADP-ribose (cADPr) is a crucial second messenger regulating intracellular calcium ([Ca2+](i)).
- Starfish oocytes are a model system for studying calcium signaling.
- Previous studies identified cortical Ca2+ patches in these oocytes.
Purpose of the Study:
- Investigate the origin of cADPr-elicited Ca2+ waves.
- Characterize the associated membrane currents.
- Determine the role of cADPr in calcium regulation.
Main Methods:
- Confocal laser scanning microscopy
- Voltage clamp techniques
- Oocyte microinjection with inhibitors (BAPTA, ruthenium red, 8-NH(2)-cADPr)
- Calcium uncaging (NP-EGTA) and InsP(3) photoliberation
Main Results:
- cADPr elicited a Ca2+ wave accompanied by a membrane current (reversal potential ~+20 mV).
- The Ca2+ response was independent of external Na+ and Ca2+, and holding potential.
- Inhibitors abolished the cADPr response; InsP(3) and Ca2+ uncaging mimicked the ionic current.
- cADPr releases Ca2+ via ryanodine receptors, triggering a cation current not involved in global Ca2+ elevation.
Conclusions:
- cADPr activates Ca2+ waves in starfish oocytes through ryanodine receptor-mediated Ca2+ release.
- A subsequent non-selective monovalent cation current is activated by the Ca2+ rise.
- This cation current does not contribute to the global intracellular calcium elevation during the cADPr-elicited wave.
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