Compliance Accelerates Relaxation in Muscle by Allowing Myosin Heads to Move Relative to Actin.

ABSTRACT: The mechanisms that limit the speed at which striated muscles relax are poorly understood. This work presents, to our knowledge, novel simulations that show that the time course of relaxation is accelerated by interfilamentary movement resulting from series compliance; force drops faster when myosin heads move relative to actin during relaxation. This insight was obtained by using cross-bridge distribution techniques to simulate the mechanical behavior of half-sarcomeres that were connected in series with springs of varying stiffness. (The springs mimic the combined effects of half-sarcomere heterogeneity and muscle's series elastic component.) Half-sarcomeres that shortened by >∼10 nm when they were activated subsequently relaxed with a biphasic profile; force initially declined slowly an

SUBMITTER: Campbell KS 

PROVIDER: S-EPMC4744171 | biostudies-literature | 2016 Feb

REPOSITORIES: biostudies-literature