Fig. 5
From: Regulation of myocardial contraction as revealed by intracellular Ca2+ measurements using aequorin
Modified from Fig. 1 of [45] with permission.
Effects of quick release on CaT and tension during twitch. CaT and tension were measured at Lmax and when a sudden length change was applied to 92% Lmax at various times before (A) and after (B–D) stimulation (indicated by arrows). Ferret ventricular papillary muscle was used. In each panel, two records obtained at Lmax and 92% Lmax are superimposed. Top trace, muscle length; second trace, CaT; third trace, tension; bottom trace, difference of CaT at Lmax and 92% Lmax (i.e., Extra-Ca2+ as clearly seen in C and D). In A, muscle length was shortened 50 ms before the stimulus. In B–D, muscle length was shortened 22, 75 and 138 ms after the stimulus, respectively. Note that Extra-Ca2+ becomes greater with greater magnitude of a fall of tension (i.e., Extra-Ca2+ greater in D than in C). ΔT, fall of tension upon shortening.