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. 1970 Jan 1;55(1):77–88. doi: 10.1085/jgp.55.1.77

The Intracellular Site of Calcium Activation of Contraction in Frog Skeletal Muscle

Saul Winegrad 1
PMCID: PMC2202966  PMID: 5410491

Abstract

Radioautography has been used to localize 45Ca in isotopically labeled frog skeletal muscle fibers which had been quickly frozen during a maintained tetanus, a declining tetanus, or during the period immediately following a tetanus or a contracture. During a tetanus almost all of the myofibrillar 45Ca is localized in the region of the sarcomere occupied by the thin filaments. The amount varies with the tension being developed by the muscle. The movement of calcium within the reticulum from the tubular portion to the terminal cisternae during the posttetanic period has a half-time of about 9 sec at room temperature and a Q 10 of about 1.7. Repolarization is not necessary for this movement. Evidence is given to support the notion that most calcium efflux from the cell occurs from the terminal cisternae into the transverse tubules.

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Selected References

These references are in PubMed. This may not be the complete list of references from this article.

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