title: Intracellular calcium movements during excitation-contraction coupling in mammalian slow-twitch and fast-twitch muscle fibers.
abstract: In skeletal muscle fibers, action potentials elicit contractions by releasing calcium ions (Ca(2+)) from the sarcoplasmic reticulum. Experiments on individual mouse muscle fibers micro-injected with a rapidly responding fluorescent Ca(2+) indicator dye reveal that the amount of Ca(2+) released is three- to fourfold larger in fast-twitch fibers than in slow-twitch fibers, and the proportion of the released Ca(2+) that binds to troponin to activate contraction is substantially smaller.
authors.affiliation: Department of Physiology, University of Pennsylvania, Philadelphia, PA 19104, USA.
authors.forename: Stephen M
authors.initials: SM
authors.lastname: Baylor
authors.forename: Stephen
authors.initials: S
authors.lastname: Hollingworth
mesh_terms: D000200:Action Potentials / Q000502:physiology*; D000818:Animals; D002118:Calcium / Q000378:metabolism*; D020013:Calcium Signaling / Q000502:physiology*; D056966:Excitation Contraction Coupling / Q000502:physiology*; D006801:Humans; D018656:Muscle Fibers, Fast-Twitch / Q000502:physiology*; D018657:Muscle Fibers, Slow-Twitch / Q000502:physiology*; D012519:Sarcoplasmic Reticulum / Q000502:physiology*
chemical_list: D002118:Calcium