Fig. 2.

5-HT (100 μM)-induced increase in superoxide in tricuspid and pulmonary valves, and pulmonary artery, is attenuated by diphenyliodonium (DPI, 10 μM), an inhibitor of several flavin-containing oxidases. The increase in superoxide was not attenuated significantly by apocynin (100 μM), an inhibitor of NAD(P)H oxidase. Vehicle (Veh) was PBS at pH 7.4. P < 0.05 vs. control (*) and vs. 5-HT only-Veh (#); n = 4 for tricuspid valve, n = 6 for pulmonary valve, and n = 7 for pulmonary artery. Analysis used controls shown in Fig. 1.