Fig. 4.

The effect of dapsone on the extracellular superoxide (O₂ ⁻) release induced by N-formyl-l-methionyl-l-leucyl-l-phenyalanine (fMLP), C5a and phorbol myristate acetate (PMA). Neutrophils (1 × 10⁶ cells mL⁻¹) were preincubated with or without dapsone at the concentrations indicated for 30 min and then stimulated with fMLP (1 μmol L⁻¹) (a), C5a (100 nmol L⁻¹) (b) or PMA (100 nmol L⁻¹) (c). After addition of cytochrome C (20 μmol L⁻¹), the reduction of absorbance at 550 nm in the absence (ΔOD₅₅₀[SOD]) was measured for 5 min using a single-beam spectrophotometer. SOD-inhibitable cytochrome C reduction corresponded to ΔOD₅₅₀–ΔOD₅₅₀[SOD]. The data shown are representative of three to four separate experiments with similar results. Dapsone suppressed the extracellular O₂ ⁻ production induced by fMLP and C5a but not by PMA. (according to Suda et al. [148])