English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

This review summarizes estimates for cytoplasmic-free concentrations of Ca2+ ([Ca2+]i) and Mg2+ ([Mg2+]i) at rest and during contraction of skeletal muscles, from which substantial quantitative information about them has been accumulated. Although the estimates of resting [Ca2+]i in the literature widely differ, which is because of the variety of difficulties related to different methodologies used, recent studies suggest that estimates of resting [Ca2+]i of approximately 0.05-0.1 microM are likely to be correct. Following action potential propagation, the Ca2+ release from the sarcoplasmic reticulum causes a transient rise of [Ca2+]i (Ca2+ transient). The large peak amplitude and brief time course of the Ca2+ transients have been established only recently by studies with low-affinity Ca2+ indicators developed in the past decade. These technical improvements in [Ca2+]i measurements have made it possible to study relationships between [Ca2+]i and force in intact muscle fibers. In the second part of this review, various estimates of [Mg2+]i in the resting muscle are discussed. Relatively recent estimates of the [Mg2+]i level appear to be about 1.0 mM. Using the current knowledge of concentrations and reaction properties of intracellular Ca2+-Mg2+ binding sites, we constructed a model for dynamic Mg2+ movement following Ca2+ transients. The model predicts that with a train of action potentials, the sustained rise of [Ca2+]i produces an elevation of [Mg2+]i of about 200 microM.

Cytoplasmic Free Concentrations of Ca2+ and Mg2+ in Skeletal Muscle Fibers at Rest and during Contraction.