Loss of one or both ahr alleles increases the aortic sensitivity to PE-mediated contraction in the presence of the NOS inhibitor, LNNA. (A) PE-induced contraction (% KCl), (B) PE-induced contraction in the presence of LNNA, and (C) difference (Δ) in PE-induced contraction in the presence and absence of LNNA of endothelium-intact thoracic aortic rings from male ahr+/+, ahr+/−, and ahr−/− mice (n=6–9/genotype). Data represent mean ± SEM and were analyzed by two-way repeated measures ANOVA, using post hoc Holm-Sidak comparisons; *p < 0.05, compared to ahr+/+ and †p < 0.05 compared to ahr−/− (A) or compared to ahr+/− (C).