Involvement of mitochondrial Na+–Ca2+ exchange in intestinal pacemaking activity

Figure 1 The effect of clonazepam on the pacemaking activity of ICCs. Clonazepam was applied to examine its effect on the pacemaking activity of ICCs. A: Under a voltage clamp at a holding potential of –60 mV, 50 µmol/L clonazepam inhibited the pacemaking currents of ICCs (n = 4). B: Clonazepam from 20 to 60 µmol/L effectively inhibited Ca²⁺ efflux from mitochondria in the pacemaking activity of ICCs. The IC₅₀ of clonazepam was 37.1 µmol/L.

Figure 2 The effect of CGP37157 in the pacemaking activity of the ICCs. CGP37157 was applied to examine its effect on the pacemaking activity of ICCs. A, B, and C: Under a current clamp (I = 0), CGP37157 inhibited the pacemaking potentials in a dose-dependent manner (n = 15). D: CGP37157 from 10 to 30 µmol/L effectively inhibited Ca²⁺ efflux from mitochondria in the pacemaking activity of ICCs. The IC₅₀ of CGP37157 was 18.2 µmol/L.

Figure 3 Effect of internal Ni²⁺ on the pacemaking activity of ICCs. In order to investigate the effect of NiCl₂ on the pacemaking activity of ICCs, we added 20 µmol/L of NiCl₂ to the internal solution. A: Under a voltage clamp at a holding potential of -60 mV, the pacemaking activity of ICCs showed a “wax and wane” phenomenon (n = 6). B: Current clamp mode (I = 0) showed the same phenomenon (n = 3).