Figure 3. Analysis of blocking kinetics in WT channels.

Histograms of open and zero-current times constructed for outward currents at +22 mV in the presence of spermine. The open-time histogram was fitted with a single exponential function. The mean open time decreased in a concentration-dependent manner. The zero-current-time histograms for currents filtered at 0.2 kHz and sampled at 1 kHz are shown. Spermine induced a component of zero-current times with the time constant indicated, which represents blocked times. The value of the truncated first bin in the zero-current-time histogram with 1 nm spermine was 57%.