Fig. 2.

Effect of 1.0 μmol/L K201 on myofilament Ca²⁺ sensitivity a relationship between free Ca²⁺ transient parameters (peak and minimum) and cell shortening amplitudes (% shortening) in response to varying external [Ca²⁺] (n = 14, *P < 0.05 vs.1.8 mmol/L for each). b as in a with additional points obtained in 1.8 mmol/L external [Ca²⁺] and K201 (0.3, 1.0 and 3.0 μmol/L; n = 24, P < 0.05 for shortening amplitudes at all concentrations vs. 1.8 mmol/L, P < 0.05 for peak [Ca²⁺]_i at 1 and 3 μmol/L K201 vs. 1.8 mmol/L). c mean ± SEM values for percentage change in amplitude of free [Ca²⁺]_i and shortening amplitudes in 1.0 μmol/L K201 expressed relative to control in 1.1 mmol/L external Ca²⁺ (100%; n = 7). d as in a with additional points obtained in 1.8 mmol/L external [Ca²⁺] and diltiazem (4.0 and 8.0 μmol/L n = 8, P < 0.05 for shortening amplitudes and peak [Ca²⁺]_i at both concentrations vs. 1.8 mmol/L and for minimum [Ca²⁺]_i at 8.0 μmol/L diltiazem vs. 1.8 mmol/L)