Figure 10. Effects of thiopental on peak developed force (DF, closed circle) and peak aequorin luminescence (AL, open circle) in ferret right ventricular papillary muscle (mean plus/minus SD, n = 9) with an intact SR (top, data from group 2) and after inactivation of SR Calcium²¹release (bottom) in muscles (group 4; mean plus/minus SD, n = 5) exposed to 10⁶M ryanodine before the thiopental dose-response experiments. **P < 0.01 for comparison with corresponding control.