Figure 7. The effect of lowering [Ca²⁺]_o on Ca²⁺ transients in submucosal interstitial cells of Cajal (ICC-SM).

(A) ICC-SM Ca²⁺ transients and Ca²⁺-firing sites were color coded and plotted as an occurrence map under control conditions with [Ca²⁺]_o = 2.5 mM. (B–E) showing the effects of reducing [Ca²⁺]_o to 2 mM B; 1 mM C; 0.5 mM D and after Ca²⁺ removal of [Ca²⁺]_o (0 mM added and final solution buffered with 0.5 mM EGTA) E. F-J Traces of Ca²⁺ PTCL activity in ICC-SM (PTCL area, blue and PTCL count, green) under control conditions F and after reducing [Ca²⁺]_o to 2 mM G; 1 mM H; 0.5 mM I and after removal of [Ca²⁺]_o as shown in J. Summary graphs of Ca²⁺ PTCLs in ICC-SM under control conditions and with reduced [Ca²⁺]_o in K (PTCL area); L (PTCL count) and M (PTCL duration). Data were normalized to controls and expressed as percentages (%). Significance was determined using one-way ANOVA, * = p<0.1, ** = p<0.01, **** = p<0.0001, n = 6. All data graphed as mean ± SEM.