Effect of 12-hydroxyeicosatetraenoic acid on cytosolic calcium in human neutrophils.

12-Hydroxy-5,8,10,14-eicosatetraenoic acid (12-HETE) has been reported to be a chemoattractant for human neutrophils. To assess its cellular mechanism, we focused on the effect of 12-HETE on cytosolic Ca2+ ([Ca2+]i) and characterized the effect of 12-HETE on [Ca2+]i in human neutrophils. 12(S)- and 12(R)-HETE increased [Ca2+]i in the presence and absence of extracellular Ca2+ in a concentration-related fashion. The elevation of [Ca2+]i by 12(R)-HETE was completely abolished by pertussis toxin treatment. U-73122, a selective phospholipase C inhibitor, depressed the 12(S)- and 12(R)-HETE-induced rise in [Ca2+]i in the presence and absence of extracellular Ca2+. 12(R)-HETE resulted in the rapid production of inositol 1,4,5-trisphosphate (IP3). Furthermore, 12(R)-HETE elicited slight depolarization of neutrophils as assessed using the fluorescent dye bis-oxonol. These results provide evidence demonstrating the signal transduction pathway in human neutrophils after stimulation with 12-HETE and suggest that 12-HETE causes a rapid rise of [Ca2+]i by mobilizing Ca2+ from an IP3-sensitive intracellular Ca2+ pool in human neutrophils.