Arachidonic acid-induced release of calcium in permeabilized human neutrophils.

The addition of arachidonic acid to a suspension of digitonin-permeabilized human neutrophils was found to induce, in a dose-dependent manner (ED50 about 15 microM), the release of calcium from internal stores. Arachidic acid was without effect, while linoleic acid and linolenic acid were (on a concentration basis) at least 5-times less active than arachidonic acid. The activity of arachidonic acid appears to be due to the fatty acid itself and not to one of its metabolites. The pool of calcium mobilized by arachidonic acid includes that sensitive to inositol 1,4,5-triphosphate. These results demonstrate a significant intracellular role for arachidonic acid at the level of the internal mobilization of calcium in human neutrophils.