Figure 5. Effects of delapril on contractile machinery in permeabilized cardiomyocytes.

A. Relationship between Ca²⁺-activated tension and intracellular Ca²⁺ content measured at an SL of 1.9 μm in permeabilized cardiomyocytes from Sham (n=16), MI (n=20) and MI-D mice (n=22). The relationship was fitted to a modified Hill equation and the pCa at which half the maximal tension is developed (pCa₅₀) was determined as an index of myofilament Ca²⁺ sensitivity (see Methods for more details). B. Mean ± S.E.M. of maximal tension (top) and pCa₅₀ (bottom) obtained from permeabilized Sham, MI and MI-D cells C. Effect of delapril on the phosphorylation level of MLC-2 in permeabilized cardiac strips from Sham (n=5), MI (n=11) and MI-D hearts (n=11). Phosphorylation levels were determined by Western blotting using a P-MLC2 antibody as described in methods. D. Effect of delapril on the phosphorylation level of TnI in permeabilized cardiac strips from Sham (n=7), MI (n=8) and MI-D hearts (n=8). Results are expressed as the mean ± S.E.M. *P<0.05 in comparison with Sham mice. †P<0.05 in comparison with MI mice.