A. Siafakakapadai et al., OLEIC ACID-INDUCED CA2- IS OLEIC-ACID AN INTRACELLULAR MESSENGER( MOBILIZATION IN HUMAN PLATELETS ), Journal of lipid mediators and cell signalling, 15(3), 1997, pp. 215-232
The purpose of this study was to explore the effect of oleic acid (OA)
on intracellular Ca2+ mobilization in human platelets. When applied e
xtracellularly, OA produced a concentration dependent rise in cytosoli
c [Ca2+] ([Ca2+](cyt)) when extracellular [Ca2+] ([Ca2+](ext)) was zer
o (presence of EGTA), suggesting that OA caused an intracellular relea
se of Ca2+. Intracellular Ca2+ release was directly proportional to en
try of OA into platelets and OA entry was indirectly proportional to [
Ca2+](ext). In permeabilized platelets, OA caused the release of Ca-45
(2+) from ATP dependent intracellular stores. Finally, our results sho
w that thrombin stimulated the release of [H-3]OA from platelet phosph
olipids. The saturated fatty acids stearic and palmitic acid did not s
timulate an increase in [Ca2+](cyt) under these conditions, but the un
saturated fatty acid, linolenic acid produced effects similar to those
of OA, suggesting specificity among fatty acids for effects on [Ca2+]
(cyt). Taken together, out experiments suggest that OA which has been
incorporated into platelet phospholipids was released into the cytosol
by thrombin stimulation. Our experiments also show that OA stimulated
Ca2+ release from intracellular stores. These results support the hyp
othesis that OA may serve as an intracellular messenger in human plate
lets. Copyright (C) 1997 Elsevier Science B. V.