X-ray diffraction experiments of skeletal muscle from Ictidomys tridecemlineaus demonstrate changes in M6 myosin meridional spacing during torpor.
A. Representative x-ray diffraction recordings from permeabilized skeletal muscle bundles from Ictidomys tridecemlineatus from summer active (SA), interbout arousal (IBA) and torpor. The M3 and M6 meridional reflections and the 1,0 and 1,1 equatorial reflections are indicated. B. Ratio of the 1,1 to 1,0 equatorial reflections from active, IBA and torpor skeletal muscle. C. M3 meridional spacing, measured in nm. D. Normalized intensity (A.U.) of the M3 meridional reflection. E. M6 meridional spacing, measured in nm. Colored circles represent the mean value obtained from each skeletal muscle bundle which was recorded. Data is displayed as mean ± SEM. One-way ANOVA was used to calculate statistical significance. * = p < 0.05, ** = p < 0.01, *** = p < 0.001. n = 5 individual animals per group.