FIG. 10.

Relationship between alpha-toxin-induced generation of O₂⁻ and MAPK cascades. (A) Rabbit neutrophils (1.0 × 10⁶ cells/ml) were incubated with or without 1.0 μg/ml alpha-toxin at 37°C for the indicated periods. The extracted phospho-MAPKs were subjected to SDS-PAGE and Western blotting using specific antibodies. *, P < 0.01, compared with phosphorylation of MAPKs induced by alpha-toxin alone. (B) Rabbit neutrophils (1.0 × 10⁶ cells/ml) were preincubated with various concentrations of PD98059, K252a, and U73122 at 37°C for 60 min and then incubated with 1.0 μg/ml alpha-toxin at 37°C for 60 s. The extracted phospho-ERK1/2, ERK1/2, and β-actin were subjected to SDS-PAGE and Western blotting using specific antibodies. A typical result from one of five experiments is shown.