A STMs showing the effect of Ca2+ free solution (buffered with 0.5mM EGTA) on ICC-SS Ca2+ transients after 4 minutes exposure to the Ca2+ free conditions. B Summary data showing the effect of Ca2+ free solution (0.5mM EGTA) on ICC Ca2+ transient frequency, amplitude, duration and spatial spread after 2–10 min exposures, c=21, n=5. All statistical comparisons are against control. C STMs showing the effect of 5 mM external Ca2+ solution on ICC-SS Ca2+ transients. D Summary data showing the effect of 5 mM external Ca2+ solution on ICC Ca2+ transient frequency, amplitude, duration and spatial spread, c=16, n=5.