Figure 4. Single cation channel activity in 100 μm ${\text{Ca}}_{\text{o}}^{2+}$.

A, effect of reducing ${\text{Ca}}_{\text{o}}^{2+}$ from 1.5 mm to 100 μm on channel currents recorded from the same patch. In 100 μm ${\text{Ca}}_{\text{o}}^{2+}$ the channel currents showed significantly longer bursts of channel activity. B, effect of reducing ${\text{Ca}}_{\text{o}}^{2+}$ from 1.5 mm to 100 μm on the open time distributions of the single channel currents shown in Fig. 4A. Changing from 1.5 mm to 100 μm ${\text{Ca}}_{\text{o}}^{2+}$ did not alter O_τ1 or O_τ2. C, burst duration distributions of the single channel currents shown in Fig. 4A. Reducing ${\text{Ca}}_{\text{o}}^{2+}$ from 1.5 mm to 100 μm did not change B_τ1 but increased the B_τ2 from 16 ms to 52 ms.