Figure 3. Comparative analysis of the Ca²⁺ responses following application of EGF at two different concentrations.

A/Proportion of cells not responding (white bar) or responding to 2 nM (grey bar, n = 40/43) or 20 pM (red bar, n = 137/281) EGF. B/Average of responsive cell Ca²⁺ signals time-locked on the first fluorescence peak and recorded over 150 sec in response to 2 nM (grey line, n = 40) or 20 pM (red line, n = 137) EGF application. C/Schematic representation of the rules used to define the properties of the fluorescence peaks during an oscillatory response. Peaks were defined as signals rising and falling through an intensity threshold (th) of 0.23, and delay, duration and inter-spike interval (ISI, difference between the starting time of 2 consecutive peaks) values were defined relative to the threshold crossing. The area under the first peak is shown in black. EGF was added 25 s after the start of the video time-lapse (white bar). D/Bar plot showing the distribution of first peak delays as defined in C elicited by 2 nM (grey box, n = 40/43) or 20 pM (red box, n = 137/281) EGF. E/Bar plot showing the distribution of first peak durations as defined in C elicited by 2 nM (grey box, n = 40/43) or 20 pM (red box, n = 137/281) EGF. F/Bar plot showing the distribution of first peak areas as defined in C elicited by 2 nM (grey box, n = 40/43) or 20 pM (red box, n = 137/281) EGF. G/Bar plots showing the distribution of average interspike intervals (Average ISI) for oscillatory cells responding to 2 nM (grey box, n = 22/43 cells) or 20 pM (red box, n =  98/281 cells) EGF.