Fig. 2. Representative plot of the change in fluorescence that occurs after injury. The average fluorescence of a 512 µm x 512 µm field of cells was recorded every 789 milliseconds. Background fluorescence, F₀, was subtracted and the percentage change in fluorescence with respect to F₀ was calculated for each time point and plotted as described in Materials and Methods. The increase in fluorescence is immediate and peaks within 15 seconds of injury and then diminishes more slowly over time to original background levels within 100 seconds. The graph is labeled with letters that refer back to the images shown in Fig. 1.