Effect of eNOS on the relaxation of aortic rings. (A) The contraction of aortic rings with 10-5 M PE before and after pre-incubation of L-NAME, 10-4 M, eNOS inhibitor. (B) The percent change in relaxation (tension PE - tension ACh/tension PE) to 10-4 M ACh after 10-5 M PE before and after pre-incubation of L-NAME. Data presented as mean ± S.E.M. and expressed as percentage of baseline tension. * P < 0.01 vs. relaxation value of corresponding group before pre-incubation of L-NAME, n = 8-10 rings from 5-6 rats.