title: Localization of the site of Ca2+ release at the level of a single sarcomere in skeletal muscle fibres.
abstract: The development of mechanical force in skeletal muscle fibres is brought about by rapid increases in the intracellular calcium concentration (Ca2+ transients) which can be detected by optical methods. Local stimulation experiments and ultrastructural evidence suggest that, at a microscopic level, these Ca2+ transients are generated by the release of Ca2+ ions from the terminal cisternae of the sarcoplasmic reticulum in response to the depolarization of the transverse tubules (t-tubules). Nevertheless, to date, there is no functional information on the exact location at which Ca2+ release takes place. The present experiments were designed to obtain direct evidence about dynamic changes in localization and microscopic distribution of Ca2+ in a single sarcomere using two independent novel methodologies: confocal spot detection of Ca2+ transients and Ca2+ imaging with pulsed laser excitation.
authors.affiliation: Department of Physiology, University of California at Los Angeles 90024.
authors.forename: A L
authors.initials: AL
authors.lastname: Escobar
authors.forename: J R
authors.initials: JR
authors.lastname: Monck
authors.forename: J M
authors.initials: JM
authors.lastname: Fernandez
authors.forename: J L
authors.initials: JL
authors.lastname: Vergara
mesh_terms: D000200:Action Potentials; D000818:Animals; D002118:Calcium / Q000378:metabolism*; D005453:Fluorescence; D007834:Lasers; D008853:Microscopy; D009132:Muscles / Q000378:metabolism*; D011892:Rana catesbeiana; D012518:Sarcomeres / Q000378:metabolism*
chemical_list: D002118:Calcium