Production of platelet-activating factor from rat cerebellar granule cells in culture

Platelet-activating factor (PAF) is a potent lipid mediator implicated in various pathological conditions, including CNS neuronal injury. However, the production of PAF by mammalian CNS neurons has not as yet been demonstrated. In the present study, we demonstrate that PAF is produced by cultured rat cerebellar granule cells. PAF was identified on the basis of chemical and enzymatic characteristics, biological activities with washed rabbit platelets, and behavior on TLC and HPLC. PAF was detected both in the cells and in the incubation medium, a result indicating the release of PAF from cultured neurons. The amount of PAF produced during a 30-min incubation was as follows: 1.02 +/- 0.10 and 0.93 +/- 0.09 pmol/4 X 10(7) cells in incubation buffer and cells, respectively (n = 10). The calcium ionophore A23187 (2.5 microM) had only a mild stimulatory effect on PAF production, a finding indicating that the neuron-generated PAF might be synthesized mainly by the de novo pathway of PAF production.