Fig. 1. Injury induces an intercellular Ca²⁺ wave. Cells were loaded with 4 µM fluo-3 AM for 30 minutes and washed two times. An initial baseline image is shown in (A). In response to a circular wound 250 µm in diameter made at 76 seconds (asterisk), cells immediately adjacent to the injury site displayed an increase in intracellular Ca²⁺ (B). The elevation in Ca²⁺ propagated as a radial pattern to neighboring cells (C-F). The response diminished over time and the intracellular Ca²⁺ levels of most cells decreased to original background levels within minutes (G). Intensity scale is shown in A, with red indicating highest Ca²⁺ levels and blue indicating lowest Ca²⁺ levels. The horizontal white bar in A represents 50 µm. Images are representative of 30 independent experiments. This series of images is taken from Movie 1 (http://jcs.biologists.org/supplemental).