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

To elucidate the essential features of Ca(2+) release from the terminal sac (TS) of the sarcoplasmic reticulum (SR) in heart muscle, a model for Ca(2+) release from the TS was constructed based on the mechanism of Ca(2+)-induced Ca(2+)-release by assuming a small TS volume. For numerical computation, we divided the cytoplasm in a half sarcomere into 50 compartments, one end of which faced the TS and determined the open probability of the Ca(2+) release channel in the TS. Ca(2+) moves from compartment to compartment by simple diffusion and is taken up from each compartment by the tubular SR via Ca(2+)-ATPase. Simulation based on one-dimensional diffusion of Ca(2+) showed that TS Ca(2+) release is smoothly graded over a wide range of levels of Ca(2+) influx when the TS is moderately loaded with Ca(2+), and it occurs in an all-or-none manner when the TS is heavily loaded with Ca(2+). The graded TS Ca(2+) release was generated with both local and uniform Ca(2+) influx into the cytoplasm. The propagation of the Ca(2+) wave was simulated by the use of a model consisting of several longitudinally consecutive sarcomeres with TS heavily loaded with Ca(2+). Mechanical alternans, characterized by an alternation of small and large twitches, was also simulated by applying Ca(2+) influx at an appropriate interval during which Ca(2+) was replenished to the TS at a constant rate. Thus the present model reflects several important aspects of TS Ca(2+) release in heart muscle.

Model for the Regulation of Ca2+ Release from the Sarcoplasmic Reticulum in Heart Muscle.