Structural alterations in the heart after long-term L-NAME and D-NAME treatment.

N(G)-nitro-D-arginine methyl ester (D-NAME), considered as an inactive enantiomer of NAME, is generally used as a negative control for NO synthase inhibition with L-NAME. The aim of this work was to compare the effect of L-NAME (20 and 40 mg/kg/day), and D-NAME (40 mg/kg/day) on hemodynamic and structural parameters in the rat cardiovascular system. After 4 weeks of treatment, blood pressure and left ventricle weight/body weight ratio increased significantly in all studied groups versus control. Myocardial fibrosis (in %) represented 0.94 +/- 0.04 in control, 4.70 +/- 0.39 in L-NAME (20 mg/kg/day), 10.54 +/- 0.91 in L-NAME (40 mg/kg/day) and 5.25 +/- 0.46 in D-NAME (40 mg/kg/day) group. We conclude that in a long-term experiment D-NAME provokes similar changes in cardiovascular system like L-NAME.