Figure 7. Effects of nominal extracellular Ca²⁺ on Ca²⁺ transients in ICC‐DMP .

A, representative image of an ICC‐DMP and ST map showing spontaneous Ca²⁺ transients in the ICC‐DMP in the presence of TTX and after the addition of nominally Ca²⁺‐free KRB solution in B. Reducing extracellular Ca²⁺ did not significantly affect the occurrence of Ca²⁺ transients. C, summary data show that there was no significant (NS) change in the rate of occurrence of Ca²⁺ events in nominal Ca²⁺‐free KRB (P = 0.57, n = 5). D, summary histograms showing the amplitudes of Ca²⁺ transients in the presence of TTX (black bars and line) and after the addition of nominal Ca²⁺‐free KRB (red bars and line) (P = 0.4, n = 5). E, summary histograms showing the spatial spread of Ca²⁺ transients in the presence of TTX and after the addition of nominal Ca²⁺‐free KRB (P = 0.76, n = 5).