Instabilities in the transient response of muscle.

摘要: We investigate the isometric transient response of muscle using a quantitative stochastic model actomyosin cycle based on swinging lever-arm hypothesis. first consider single pair filaments, and show that when values parameters such as displacement cross-bridge elasticity are chosen to provide effective energy transduction, T2 curve (the tension recovered immediately after step displacement) displays region negative slope. If filament compliance discrete nature binding sites taken into account, slope is diminished, but not eliminated. This implies there an instability in dynamics individual half sarcomeres. However, symmetric whole sarcomeres rearrangement becomes important during transient: recovered, some lengthen whereas others shorten. leads flat curve, observed experimentally. In addition, we isotonic for range parameter damped oscillations, recently experiments fibers. conclude it essential collective many sarcomeres, rather than interpreting muscle.