Effect of duration of pretreatment with CGS 21680 or CP-532,903 on superoxide production by Percoll gradient purified bone marrow neutrophils in response to fMLP. Neutrophils were incubated (37° C) with vehicle, CGS 21680 (100 nM), or CP-532,903 (100 nM) in the presence of ADA (1 unit/mL) for the times indicated prior to stimulation with fMLP (1 μM). Superoxide produced was measured using the chemiluminescent probe MCLA (0.5 μM). Results (mean ± SEM, n = 4) are presented as the percentage of superoxide produced compared to the corresponding vehicle-treated group.