In vitro and in silico experiments to identify the influence of temperature on skeletal muscle calcium and force dynamics

Temperature has been shown to influence skeletal muscle performance. To be able to understand and quantify the influence of temperature on local calcium and force dynamics, in vitro and in silico experiments were performed in mouse EDL. The spatiotemporal model of Baylor and Hollingworth (J Gen Physiol. 1998 112:297–316) was adapted in such a way that it was able to describe local calcium dynamics in EDL at different temperatures. Most processes in the sarcomere were temperature dependent and were scaled with Q10 values based on literature. Model simulations were performed for a stimulation frequency of 1–10–30–60–90–120 Hz and muscle temperatures of 15–20–25–30–35C. In parallel, the mechanics of isometric contractions of isolated mouse EDL were measured for the same conditions as the simulations (ter Veld et al. 2006 Pflugers Archiv 452: 432–8). For increasing muscle temperatures, shorter rise and decay times of the Ca2+ pulse were predicted by the model. Similar trends were obtained for the rise and decay time of the measured force. For increasing stimulation frequency, the model predicted an increase in baseline and maximal Ca2+ concentration, while the measurements showed similar trends for the produced force. On top, the experiments showed that stimulation frequency influenced the decay rate at 35C. Furthermore, the experiments will be used to validate Q10 values in the model as well as the total amount of Ca2+.