Inositol phospholipids are probably not the source of arachidonic acid for eicosanoid synthesis in astrocytes.

In astrocyte-enriched cultures of the rat cerebral cortex the Ca2+ ionophore A23187 provoked the breakdown of inositol phospholipids, the liberation of arachidonic acid and the release of prostaglandins E2, F2 alpha, I2 and thromboxane A2. However, agonists for receptors also coupled to inositol phospholipid metabolism in these cells failed to produce an increase in the release of both arachidonic acid and eicosanoids. Results suggest that the A23187-stimulated release of arachidonic acid and eicosanoids is caused by a phospholipase A2-mediated attack on lipids other than the inositol phospholipids. Moreover, receptors linked to inositol lipid turnover are not involved in the control of eicosanoid release from astrocytes.