Fig. 6.
Effect of endothelium removal or blockade of NO-cGMP pathway on ACh-induced relaxation of pulmonary artery. Isolated pulmonary artery rings from Nx, Hx, Su, and Su/Hx rats were either kept endothelium-intact (open circles), pretreated with the NOS inhibitor l-NAME (3 × 10−4 M) (closed circles) or the guanylate cyclase inhibitor ODQ (10−5 M) (open triangles) for 15 minutes, or endothelium-denuded (closed triangles). The vessels were stimulated with submaximal concentration of Phe, then stimulated with ACh (10−9–10−5 M), and the percentage of relaxation of Phe contraction was measured. Data represent means ± S.E.M., n = 7–11. *P < 0.05, vessels treated with l-NAME or ODQ or endothelium denuded vs. control nontreated endothelium-intact vessels.