The elevation of cGMP plasma levels in DCM mice on a LSD were (~3-fold) seems likely due to the NOS-NO axis rather than to NP system network, as suppression of NOS by L-NAME reduced total plasma NO levels (~2-fold) and cGMP (~3-fold) to the levels detected in DCM mice on a NSD. Here, NOS1 is linked to familial dilated cardiomyopathy.