We haven't tried that combination, but regularly cultures brain endothelial cells and astrocytes. Suppose youre interested in getting the PC12's to differentiate into a neuronal phenotype? You could add C6 on the lower surface of Transwell polycarbonate supports, let them grow for a couple of days and then add PC12's to the upper surface. You might also add dexamethasone after some days of co-culture, in order to push the terminal differentiation...