Figure 4.

Functional coupling of astrocytic end feet visualized by diffusion of Lucifer yellow. A, An astrocyte filled with the gap junction-permeable indicator Lucifer yellow in a freshly prepared cortical slice. Lucifer yellow diffused preferentially along the vessel wall. Red arrowhead indicates Lucifer yellow-filled pipette; yellow arrowheads indicate vessel wall. Current injection failed to evoke action potentials (bottom panel). B, Another example of intercellular diffusion of Lucifer yellow along the vessel wall. An astrocyte was filled with Lucifer yellow by a patch electrode (red arrowhead), resulting in extensive intercellular diffusion into neighboring astrocytes and an outlining of their processes plastered around a vessel. Inset, After multiphoton imaging, the slice was fixed and visualized under DIC optics and fluorescence microscopy to depict the position of the Lucifer yellow-filled astrocyte (red arrow-head) in relation to the vessel (yellow arrowhead).