Figure 2.

Effect of chronic SNP treatment on contractility and calcium. Freshly isolated cardiomyocytes were cultured in serum-free medium and treated with the all-NOS inhibitor L-NMMA 100 µM or sodium nitroprusside as indicated for 18 h before measurement at 37°C and with 2 Hz electrical field pacing. SNP at 50 and 100 µM caused a significant reduction of fractional shortening (left) and of the late phase of relaxation, but no significant change of systolic fura-2 ratio (right) or its kinetics in the late phase of relaxation. L-NMMA did not induce significant changes in any of the measured parameters. Typical contraction and fura2-transients are shown below for each treatment. Black arrows below the time axis indicate the pacing events. *P<0.05 vs untreated, **P<0.001 vs untreated, n = 20 cells from 3 hearts.