Arachidonic acid and prostaglandins enhance potassium-stimulated calcium influx into rat brain synaptosomes.

Exogenous administration of arachidonic acid, prostaglandins PGF2 alpha, PGD2 and PGE2 increased potassium-stimulated uptake of calcium in rat brain synaptosomes from the brain of the rat, but had no effect on the basal uptake of calcium. Arachidonic acid-induced uptake of calcium was mediated by its prostaglandin metabolites, because a cyclooxygenase inhibitor, indomethacin, inhibited the response. L-Type calcium channel blockers, such as verapamil, diltiazem and nimodipine, blocked both KCl- and prostaglandin-enhanced potassium-stimulated influx of calcium in the brain. These results suggest that prostaglandins act as a calcium ionophore, through L-type voltage-sensitive calcium channels.