Figure 6

Comparison of twitch responses. Twitch responses - A comparison between three types of steady state twitch responses from an isolated rat ventricular myocyte viz. isosarcometric, unloaded and isometric (KSE = 2). Fixed SL in the isosarcometric case and the initial pre-contraction SL in the isometric case are chosen as 2.2 μ m. Equilibrium SL in the unloaded case is 1.9 μ m. (A) Traces for normalized force in each of the three cases with an overlay of normalized [C a^{2 +} ] _myo transient responsible for the twitch and (B) Phase plots of normalized force versus the instantaneous C a^{2 +} concentration in the cytosol in each of the three cases. Note the overlap of ♦ and ■ in panel iii. Model generated data corresponds to an idealized rat ventricular myocyte at 22.5°C.