ACTIVATION OF K+ CURRENT IN MACROPHAGES BY PLATELET-ACTIVATING-FACTOR

Puff application of platelet activating factor (10-8 M) onto peritoneal macrophages from thioglycollate-stimulated mice induced an outward current at a holding potential of -63 mV. The current was suppressed by an antagonist Y-24180 but not by CV-3988. Charybdotoxin (10-6 M) suppressed the current. Reversal potentials were dependent on external K+ concentrations. The current was not suppressed in Ca2+-free EGTA-containing solution but was completely abolished in BAPTA-AM containing solution. These results suggest that platelet activating factor activates a Ca2+-dependent K+ channel. © 1992 Academic Press, Inc.