Cultured PC showing CaB immunostaining (a) and S100B fluorescence (b) in 15-day-old cultures. PC-enriched cultures were prepared from the cerebella of 0- to 1-day-old wild-type mouse pups. PCs were identified by size, asymmetric arbors, immunoreactivity to CaB, and failure to express glial fibrillary acidic protein. In this preparation, cultures were incubated overnight with Oregon Green-tagged S100B protein (500 ng/ml). CaB-positive PC shows internalized S100B. c DAPI (staining nuclei) and d merged image of a, b, and c. Bars=10 μm