Abstract
SKELETAL muscle uses voltage sensors in the transverse tubular membrane that are linked by protein-protein interactions to intracellular ryanodine receptors, which gate the release of calcium from the sarcoplasmic reticulum. Here we show, by using voltage-clamped single fibres and confocal imaging, that stochastic calcium-release events, visualized as Ca2+ sparks, occur in skeletal muscle and originate at the triad. Unitary triadic Ca2+ release events are initiated by the voltage sensor in a steeply voltage-dependent manner, or occur spontaneously by a mechanism independent of the voltage sensor. Large amplitude events also occur during depolarization and consist of two or more unitary events. We propose a 'dual control' model for discrete Ca2+ release events from the sacroplasmic reticulum that unifies diverse observations about Ca2+-signalling in frog skeletal muscle, and that may be applicable to other excitable cells.
Original language | English (US) |
---|---|
Pages (from-to) | 455-458 |
Number of pages | 4 |
Journal | Nature |
Volume | 379 |
Issue number | 6564 |
DOIs | |
State | Published - Feb 1 1996 |
Externally published | Yes |
ASJC Scopus subject areas
- General