Figure 7
Visco-elastic properties of small fiber bundles from soleus muscles of young DesR349P knock-in mice. (a) Representative example recordings of passive force during fast length-extension jumps in 10% of L0 intervals. Fiber bundles were acutely stretched and kept at that length for 5 s before proceeding to the next 10% stretch (range: 10–60% L0). Force responses at each step consist of an instantaneous restoration force (FR) followed by a relaxation phase during which force declined to a plateau. The FR values, time constants during exponential force relaxation (τrelax) and ΔF during relaxation were analyzed. FR-length relations are much steeper in the DesR349P mutated preparations over the wt and are steeper for the hom over the het mutation (right panel in (a): solid line refers to mean exponential curve reconstructed from the mean parameters of each individual curve fit; dashed line refers to exponential fit through the mean data). (b) ΔF-ΔL relationships showing the mean relaxation data for each genotype. Those indicate a more reduced relaxation in the hom genotype than in the wt. (c) Maier-Kaplan curves showing the percentage of still intact bundles at a given stretch jump.
