Fig. 2. Dye coupling is present between cells in the neurosphere and between differentiating astrocytes. Lucifer Yellow (LY) was microinjected by iontophoresis into single cells. Fluorescence micrographs were taken 5 minutes after injection; insets show the corresponding phase-contrast views of the same fields. Dye coupling was strong between cells located in the neurosphere center (A) and between cells identified as astrocytes (B). By contrast, no LY diffusion to adjacent cells was observed when an oligodendrocyte (C) or a neuron (D) was microinjected. Bar, 10 µm.