PLASMINOGEN MEDIATES AN INTERACTION BETWEEN MICROGLIA AND DOPAMINERGIC-NEURONS

Plasminogen (PGn), which was identified as a secretory product from mi croglia, increased dopamine uptake and the number of tyrosine-hydroxyl ase-expressing neurons in cultured rat mesencephalic neurons. I-125-PG n was found to bind specifically much more to mesencephalic neurons co mpared to other glial cells. The binding was also recognized in plasma membrane prepared from embryonic rat brain. Furthermore, ligand blott ing analysis revealed that I-125-PGn binds to a 45-kD protein in plasm a membrane. These results suggest that PGn-dependent neurotrophic effe cts may be induced through the specific binding of PGn to the 45-kD PG n-receptor-like protein in neurons.