Applications of DAPI Cytochemistry to Neurobiology

4', 6-Diamidino-2-phenylindole hydrochloride (DAPI) is a fluorescent dye with high affinity for DNA. We have employed it as a fluorescent chromatin counterstain on sections immunofluorescent-stained using rhodamine and on tissues enzymatically stained using β-galactosidase. DAPI also allows easy identification of mitotic figures and can be used to supplement cytochemical studies involving cell division in the nervous system.