PAF receptor inhibition with WEB2086 specifically inhibits neutrophil spreading on SCIP monolayers. (A,B) Isolated neutrophils (1 × 10⁶/mL) in Tyrode buffer containing 1 mM CaCl₂/MgCl₂ were pretreated with Me₂SO (Control) or 30 μM of the PAF receptor antagonist, WEB2086, for 5 minutes prior to perfusion over SCIP monolayers at 150 s⁻¹ for 5 minutes. Neutrophil-platelet monolayer interactions were visualized by phase-contrast microscopy and the proportion of adherent neutrophils forming stationary adhesion contacts or spreading was quantitated. Results are presented as means (± SEM; n = 4). *P < .05. (C) Isolated neutrophils were perfused over spread platelet monolayers at 150 s⁻¹ for 5 minutes. At the end of the 5-minute cell perfusion, Tyrode buffer supplemented with vehicle (Control) or exogenous PAF (+ PAF) (700 nM) was perfused over adherent neutrophils for 5 minutes. The proportion of neutrophils exhibiting spreading was quantitated over the 10-minute perfusion period. Results are presented as means (± SEM; n = 4). **P < .01.