FIGURE 4.
Effect of PIO on mean open- (A) and closed-time (B) histograms of BKCa channels recorded from mHippoE-14 hippocampal neurons. The holding potential was set at +60 mV, and inside-out configuration was performed. In control (left side), the open-time histogram of the channel was fitted by a single exponential function (indicated by red smooth line) with a mean open time of 1.9 ms, while the closed-time histogram was by a sum of a two-exponential function with a mean closed time of 3.5 and 47.5 ms. After addition of 10 μM PIO (right side), the mean open time was increased to 2.7 ms, and the slow component of closed time was shortened to 28.7 ms; however, minimal change in the fast component of closed time (i.e., 3.4 ms) in the presence of this compound. Of note, the abscissa and ordinate in each histogram indicate the logarithm of open or closed time (ms) and the square root of even number, respectively. Data were taken from a measurement of 100 channel openings. The vertical black dashed lines are placed at the values of mean open or closed time for BKCa channels.