Fig. 4. Properties of cortical neurons cultured on a glial cell layer for 2 days. (A) An inhibitory neuron (arrow) revealed by anti-GABA staining. (B) Two excitatory neurons (arrows), each bearing an axon (arrowheads), were revealed by antiphosphorylated neurofilament staining. The antibodies to phosphorylated neurofilaments also stain nonspecifically the nuclei of cells including those of glia. Bar, 100 µm.