Figure 1.

Concentration-dependent effects of SNAP on cyclic GMP levels in the absence and presence of ODQ in cardiomyocytes. The cyclic GMP levels (in pmol mg⁻¹ protein) amounted to 4.9±0.4 under control conditions and to 9.7±2 at 1 μM SNAP, to 14.4±2.9 at 10 μM SNAP, to 19.3±5.1 at 100 μM SNAP, and to 20.1±4.3 at 300 μM SNAP (n=9 each). In the presence of ODQ (50 μM), the cyclic GMP levels (in pmol mg⁻¹ protein) were 11.2±3.6 at 1 μM SNAP, 17±5 at 10 μM SNAP, 22.1±5.4 at 100 μM SNAP, and 21.3±5.1 at 300 μM SNAP (n=9 each). The data were statistically not different in the absence and presence of ODQ (50 μM) and were approximated by one sigmoid concentration-response curve with an EC₅₀ of 4 μM. Data represent means±s.e.mean.