Figure 3: (a) Effect of vardenafil (10−7-10−6 M) on the cumulative-concentration curve induced by extracellular Ca+2 in endothelium-denuded pulmonary artery rings. Data are reported as mean ± standard error of the mean (SEM) of 12 rats. *P < 0.05 and **P < 0.01 versus control group. (b) Effect quinoxalin-1-one (ODQ) (10−4 M) incubation in the cumulative addition of CaCl2 (3 × 10−5-3 × 10−2 M). Results are presented as mean ± SEM of 12 rats. *P < 0.05 and **P < 0.01 versus group without ODQ incubation
