Figure 3.
NO-induced cGMP response in HEK cells stably expressing NO-sensitive GC and PDE5. (A) HEK-GC cells with low (HEK-GC/PDE5) or high (HEK-GC/PDE5high) expression level of PDE5 were stimulated with GSNO (100 μM), and cGMP levels were measured at the indicated time points. (B) For comparison, the NO-induced cGMP responses in human platelets (open squares) and rat aortic strips (open triangles) are shown in the same graph as the response in HEK-GC/PDE5; note that these data are expressed as percentage of maximum cGMP. (C) HEK-GC/PDE5 and HEK-GC/PDE5high cells were incubated with sildenafil (100 μM) for 10 min and then stimulated with GSNO (100 μM); cGMP levels were determined at the indicated time points.