Key result
Increasing extracellular Ca2+ from 1 to 2.5 mM increased twitch force from 61 to 93 kPa, driven by a proportional increase in the fraction of actin-attached motors from 0.08 to 0.12.
Population
Trabeculae dissected from the right ventricle of the rat heart
Design
Preclinical
Authors
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Supports refined models of cardiac contractility; leaves open translation to human myocardium.
The study defines the mechano-kinetic properties of cardiac myosin in situ, demonstrating that increased twitch force with higher extracellular calcium is due to a proportional increase in attached motors, each bearing a constant average force.
Pinzauti et al. (2018) studied Cardiac myosin mechanics. Extracellular Ca2+ concentration was evaluated on Half-sarcomere stiffness and fraction of actin-attached motors. Increasing extracellular Ca2+ from 1 to 2.5 mM increased twitch force from 61 to 93 kPa, driven by a proportional increase in the fraction of actin-attached motors from 0.08 to 0.12.
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