Figure 8.

Aged Draggen muscle. In aged Draggen muscle, we found no evidence of a change in baseline muscle excitability with age (MVRCs and frequency ramp). However, caffeine contracture force and energy charge were significantly lower in old Draggen muscle, and core‐like regions were found in old Draggen but not WT muscle. Taken together, our data suggest that progressive acquired RyR1 dysfunction and associated impairment of energetic homeostasis are responsible for the fixed weakness in old Draggen mice.