Fig. 4.
After the phenylephrine (10-5 M)-induced maximum contraction in the endothelium-intact rings reached a stable tension in the absence or presence of indigo carmine (10-5 M), 10-4 M Nω-nitro-L-arginine methyl ester (L-NAME) was added directly to the organ baths. The L-NAME-induced contraction was assessed in the absence or presence of indigo carmine (10-5 M). The data is shown as the mean ± SD, and is expressed as the percentage change from the maximum contraction induced by 10-5 M phenylephrine (10-5 M phenylephrine-induced maximum contraction: 1.87 ± 0.49 g [N = 9] and 3.42 ± 1.17 g [N = 9] for the rings not treated with indigo carmine and the indigo carmine [10-5 M] pretreated rings, respectively). *P < 0.001 versus no drug.