Platelet activating factor and leukotriene B4 induce hyperpolarization of human endothelial cells but depolarization of neutrophils.

We studied one expression of cell activation in neutrophils (PMN) and endothelial cells (EC), membrane potential changes [assessed by the fluorescent dye, di-C-O5(3)]. Human neutrophils responded with depolarization after exposure to fMLP, LTB4, A23187, PAF and PMA. In contrast, only PAF and LTB4 induced membrane potential changes in human umbilical vein EC, which responded with increased fluorescence, possibly indicating membrane hyperpolarization. These discordant responses may reflect processes of significance for interactions between EC and PMN.