Stimulatory effect of veratridine on lysophosphatidylethanolamine formation in rat brain synaptosomes

[3H]-Arachidonic acid incorporation into phospholipids of synaptosomal lysates prepared from veratridine-treated synaptosomes was examined. Synaptosomal lysates were shown to acylate exogenously added lysophosphatidylcholine, lysophosphatidylinositol, and lysophosphatidylethanolamine, when incubated with [3H]-arachidonic acid, ATP, CoA and MgCl2, yielding the respective phospholipids. Preincubation of synaptosomes with veratridine for 30 sec gave rise to an increase in [3H]-arachidonic acid incorporation into phosphatidylethanolamine, but not phosphatidylcholine nor phosphatidylinositol, indicating that lysophosphatidylethanolamine might be produced by veratridine. This increase of radioactivity in phosphatidylethanolamine caused by veratridine was completely inhibited by 1 microM tetrodotoxin or in calcium-free condition. These observations show that lysophosphatidylethanolamine was formed in a calcium-dependent manner and accumulated in synaptosomes treated with veratridine, which may relate to its action on the sodium channel and enhanced calcium influx.