TGF alpha stimulation of phosphatidylinositol hydrolysis in mesencephalic cultures requires neuron-glia interactions

To elucidate the role of TGF alpha as a growth factor in the developing brain and to obtain information on signal transduction mechanisms mediating these effects, we measured the hydrolysis of phosphatidylinositol (PI) in cultures from fetal rat brain cells. Stimulation of PI breakdown induced by TGF alpha was observed in cultures of mesencephalic cells containing both neuronal and non-neuronal cells, whereas TGF alpha was ineffective in both pure neuronal and pure glial cultures. These findings are compatible with the view that TGF alpha plays a role during brain development and that its actions on PI hydrolysis, requires the presence of neuronal and glial cells.