Fig. 3

(A and B) Inhibition of PGE₂ formation in adult zebrafish by (A) indomethacin (IC₅₀ 13 nM) and (B) NS-398 (IC₅₀ 93 nM). The data are means (±SEM) of seven independent experiments. (C and D) Analysis of inhibitor selectivity in COS-7 cells overexpressing either (C) zCOX-1 or (D) zCOX-2. Data are means (±SEM) of four experiments. (E-G) Zebrafish thrombocyte aggregation induced ex vivo by ADP (16 μM) after exposure of adult zebrafish to either indomethacin or NS-398. (E) A representative experiment showing single thrombocytes after ADP stimulation in blood from an indomethacin-treated fish. Immunostaining for GPIIb/IIIa was used as a thrombocyte marker. (F) Thrombocyte aggregation induced by ADP in blood from an NS-398-exposed fish. (G) In indomethacin (Indo)-treated fish, the frequency of observed aggregation was reduced to four of 10 experiments, whereas vehicle or NS-398-treated zebrafish exhibited platelet aggregation in all experiments either spontaneously (black bars) or ADP-induced (hatched bars) in 10 experiments per treatment group. (H) Bleeding time (seconds) in adult zebrafish after exposure to various concentrations of indomethacin and NS-398. Only the nonselective inhibitor indomethacin resulted in prolongation of bleeding time. Data are means (± SEM) of five experiments per group.