Pii: S0006-8993(02)02866-4

The phospholipid mediator platelet-activating factor (PAF) increased the release of prostaglandin E (PGE ) from astrocyte-enriched 2 2 cortical cell cultures in a concentrationand time-dependent manner. The nonhydrolyzable PAF analog methylcarbamyl-PAF (mc-PAF), the PAF intermediate lyso-PAF, and arachidonic acid (AA) also produced this effect. In contrast, phosphatidlycholine (PC) and lyso-PC, lipids that are structurally similar to PAF and lyso-PAF, had no effect on PGE production, suggesting that PAF-induced PGE release is 2 2 not the consequence of nonspecific phospholipid-induced membrane perturbation. Antagonism of intracellular PAF binding sites completely abolished the ability of mc-PAF and lyso-PAF to mobilize PGE and attenuated the AA effect. Antagonism of the 2, G-protein-coupled PAF receptor in plasma membranes had no significant effect on mc-PAF, lyso-PAF or AA-induced PGE release. Based 2 on the present findings, we hypothesize that intracellular PAF is a physiologic stimulus of PGE production in astrocytes. 2  2002 Elsevier Science B.V. All rights reserved. Theme: Cellular and molecular biology