Calcium uptake in glycerol-extracted rabbit psoas muscle fibers II. Electron microscopic localization of uptake sites

✍ Scribed by Pease, D. C. ;Jenden, D. J. ;Howell, J. N.

• Book ID: 102880565
• Publisher: Wiley (John Wiley & Sons)
• Year: 1965
• Tongue: English
• Weight: 834 KB
• Volume: 65
• Category: Article
• ISSN: 0095-9898
• DOI: 10.1002/jcp.1030650203

✦ Synopsis

An effort has been made to ascertain the site of calcium uptake i n rabbit psoas muscle by electron microscopy. Following a brief glycerol extraction, small groups of fibers were exposed i n a suitable electrolyte environment to calcium and ATP. Conditions were such that calcium was accumulated as a n insoluble oxalate salt.

Conventional preparatory procedures for electron microscopy were modified so that the calcium oxaIate deposits were retained in situ in ultrathin sections. These were found localized i n the longitudinal component of the sarcoplasmic reticulum including the terminal dilatations which form the outer elements of the triads. The possible partici- pation of the intermediate element of the triad in the uptake of calcium could not be determined. The results are regarded as direct evidence that the sarcoplasmic reticulum is intimately concerned with the uptake and release of calcium associated with the contraction-relaxation cycle.