FIGURE 2.

Effects of intracellular loading of Ca²⁺ chelators on cell shortening expressed as percent change in cell length (ordinate). Cells were superfused with normal Tyrode's solution that contained 1.0 mM Ca²⁺, and field stimulation evoked twitch contraction every 5 min. After the first twitch contraction was recorded at time zero, 0.1% DMSO and then 0.1% DMSO plus either 5 μM BAPTA AM (•) or 5 μM dimethyl BAPTA AM (x's) were added during the periods indicated by horizontal bars at the top. Symbols show mean ± SE of 11 (for BAPTA AM) or 12 cells (for dimethyl BAPTA AM).