Hello Carla, to distinguish between nuclear and cytoplasmic proteins it is helpful to use nuclear counterstains. In bright field hematoxyline is very commen, in immunfluorescence you could use Dapi . It is very easy when you are using Dapi in a mounting medium for immunfluorescence. To detect dapi you need either a suitable filter setting (370-400 nm Exitation) or a correspondig laser system for LSM.