Use of cytochalasin B to distinguish between early and late events in neutrophil activation.

Cytochalasin B greatly enhances secretion of beta-glucuronidase and generation of superoxide on stimulation of rabbit peritoneal neutrophils with the soluble chemotactic factor N-formylmethionylleucylphenylalanine (f-Met-Leu-Phe). There are smaller changes due to cytochalasin B on binding of f-Met-Leu-[(3)H]-Phe, stimulation of phosphatidylinositol turnover and the stimulated increase in the permeability of the cell membrane to Ca(2+). These latter changes are probably artefactual and arise as secondary consequences of cell stimulation. Our observations support the notion that changes in Ca(2+) permeability of membranes and stimulation of phosphatidylinositol turnover reflect early stages in the sequence of events initiated by f-Met-Leu-Phe binding to its receptor and which lead to cell activation phenomena such as secretion and superoxide production.