Calcium channel that mediates the release of Ca2+ from the sarcoplasmic reticulum into the cytoplasm and thereby plays a key role in triggering muscle contraction following depolarization of T-tubules. Repeated very high-level exercise increases the open probability of the channel and leads to Ca2+ leaking into the cytoplasm. Can also mediate the release of Ca2+ from intracellular stores in neurons, and may thereby promote prolonged Ca2+ signaling in the brain. Required for normal embryonic development of muscle fibers and skeletal muscle. Required for normal heart morphogenesis, skin development and ossification during embryogenesis.