Roles of cytosolic phospholipase A(2) and platelet-activating factor receptor in the Ca-induced biosynthesis of PAF

Casein-elicited peritoneal exudate cells (PEC), mainly consisted of neutrop hils, were collected from platelet-activating factor receptor-knock-out (PA FR-KO), cytosolic phospholipase A(2) knock-out (cPLA(2)-KO), and wild-type (WT) mice. After stimulation of PEC with calcium ionophore A 23187, PAF lev els were measured by radio-ligand binding assay using receptor-rich membran e fraction prepared from the PAF receptor transgenic mice. We found that th e level of PAF production by PEC was not different between WT and PAFR-KO m ice. On the other hand, cPLA(2)-KO mice were deficient in the PAF productio n. These results provide the direct evidence while cPLA(2) is essential in the production of PAF, PAF receptor deficiency has little effect on the PAF production. (C) 2000 Academic Press.