Figure 3. Comparison of the vasorelaxing activity of SY (A) and NA (B) in the early stage or advanced stage. Comparison of SY and NA in the advanced stage (C). Dipeptide was applied at a dose of 1 uM. Values are expressed as the means ± SEM (A, n=3; B, n =4-5; C, n = 3). *P < 0.05, compared with the early stage group (A–B). *P < 0.05, compared with SY group (C).