Figure 1.

An electrically-evoked astrocytic calcium wave traversing a cell-free lane. (A) The phase-contrast image of a bed of astrocytes in which a cell-free lane had been created 6 hr earlier. Also in view is the extracellular stimulating electrode ≈10 μm above the astrocyte upper surface. The red square delineates the field of fluorescent imaging of fluo-3 signals. (B) Cellular outlines showing the astrocytic bed, the cell-free lane, and all of the astrocytes participating in the calcium wave during the observation time depicted on the left. (C) Pseudocolor images of the change in fluorescent signal (F/Fo) in the astrocytes at selected time points. The images were collected at (from the top): 3, 16, 22, and 36 sec after stimulation. Note that in the third frame from the top, the first astrocytes on the distal side of the calcium wave show a response, which subsequently spreads to additional astrocytes. While the magnitude of spread, amplitude of response, and number of participating cells can vary in each experiment, most preparations with lanes of less than 100 μm show responses similar to that shown in this figure. (Bar = 50 μm.)