Figure 2.

The Ca²⁺ dependence of Popen for mutant ΔE. (A) Inward potassium currents recorded at −80 mV and filtered at 10 kHz from a macropatch exposed to the indicated [Ca²⁺] demonstrate that Popen increases in a Ca²⁺-dependent manner when voltage is constant. The corresponding all-points amplitude histograms are plotted in B on a semi-log scale and were constructed from 30-s recordings at each [Ca²⁺]. The dose–response relation for the effect of Ca²⁺ on Popen at negative voltage (−80 mV) is shown in C. For determination of Popen see Materials and methods. Each point represents the average of between 7 and 17 patches at each Ca²⁺ concentration tested. Error bars represent SEM.