A STMs of the effect of EFS (10 Hz, 10 sec) on ICC-SS Ca2+ transients in the presence of atropine (1 μM) before and after addition of the P2Y1 receptor antagonist MRS 2500 (1 μM). B Summary effects of EFS in the presence of atropine on the frequency, amplitude, duration and spatial spread of Ca2+ transients, comparing Pre EFS period to the EFS period and comparing the EFS period to EFS + MRS 2500, c=9, n=3.