PLATELET-ACTIVATING-FACTOR INDUCES NERVE GROWTH-FACTOR PRODUCTION BY RAT ASTROCYTES

During the course of brain injury and inflammation there is an enhanced secretion of neurotrophic substances. We have examined the effect of platelet activating factor (PAF), which has been associated with various pathological conditions in the central nervous system, on the secretion of nerve growth factor (NGF) by astrocytes. Enriched cultures of rat cortical astrocytes were treated with various concentrations of PAF for different periods of time. PAF induced a dose-dependent increase in NGF secretion, the maximal increase of 120% obtained with 50 nM PAF after 48 h of treatment. This effect was blocked by the specific antagonist WEB 2086 and was not related to a proliferative response of the cells to PAF. Concomitant treatment of the cells with PAF and tumor necrosis factor-alpha resulted in a synergistic increase in NGF secretion. These results indicate that PAF may provide a neurotrophic signal to injured neurons and may cooperate with TNF-alpha in this effect.