Maximum relaxation [of phenylephrine (PE)-induced tone] induced by nitrite (10 µM) after 20 min, in endothelium-intact aortic rings. Nitrite produces a marked relaxation compared to control *** (P < 0.001), which is inhibited in part by both indomethacin (5 µM) and 1H [1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one (ODQ) (10 µM), respectively, and completely inhibited by indomethacin (5 µM) and ODQ (10 µM) in combination *** (P < 0.001) compared to nitrite alone (n= 5 in all cases).