Fig. 4.
Relation between slow kREL and tension cost of different striated muscle preparations. There is a significant correlation (r = 0.90) between slow relaxation kinetics of myofibrils (15 °C) and the tension cost of larger permeabilized preparations (20 °C) from a variety of striated muscle tissues in spite of potential differences in the experimental conditions used in the different laboratories were the measurements were taken. Tension cost data of human atrial and ventricular preparations are from Narolska et al. (2005); slow kREL data for the myofibrils from human atrial and ventricular samples are from Piroddi et al. (2007). Tension cost data of rabbit psoas (consistent with earlier measurements), are from Joumaa et al. (2017); slow kREL data for the myofibrils from the same muscle are from Kreutziger et al. (2008). Tension cost and slow kREL data for skinned mouse ventricular trabeculae and myofibrils are from Ferrantini et al. (2017). Tension cost and slow kREL data for skinned mouse atrial trabeculae and myofibrils are unpublished data from the Authors’ laboratory. All data are shown as mean ± SEM