Forty mature male rats (Wistar strain) were maintained alive for 40 days, separated in four groups of five rats each (Control, L-NAME, L-NAME + Enalapril, L-NAME + Verapamil). Three aortic wall parameters were analyzed, as follows: the Q A(SMN) (the number of the tunica media smooth muscle nuclear profiles per area), the S V(lamellae) (surface density of the aortic lamellae), and the aortic wall thickness (AWT). Rats of the L-NAME group showed high blood pressure and cardiac hypertrophy. The AWT, the Q A(SMN) and the S V(lamellae) showed the same tendency among the groups. The increased AWT, or the reduced Q A(SMN) and the S V(lamellae) in l-NAME rats were not completely prevented by the administration of enalapril or verapamil. Hypertension causes the AWT increase by hypertrophy of the lamellar units of the media layer (S V(lamellae) decrease) and the following rarefaction of the smooth muscle nuclei (the Q A(SMN) decrease). The relative number of the smooth muscle cells (SMC) nuclei in L-NAME rats was not confirmed when this number was corrected by the arterial wall area. This does not support the SMC intense proliferation in animals with NO deficiency with the L-NAME dose and the duration used in this experimentation.