Figure 3.

Conductance characteristics of fusion pores in phospholipid membranes. (A) Time-resolved fusion pore conductance in experiments with nystatin-permeabilized liposomes. Four independent short segments of membrane current, digitized at 400 Hz on a computer, are presented (after 10 points averaging and decimation to reduce noise) as typical examples of fusion pores. Conductance was estimated for the fusion pore in series with a 4.7-nS liposome (average liposome conductance). (B) Frequency histogram of maximum pore conductances. As in A, conductance was estimated for the fusion pore in series with a 4.7-nS liposome. (C) Histogram of pore lifetimes. Pore lifetimes were determined by analysis of the 10-point averaged and decimated data, by picking the first and last point of transients continuously above the noise of the baseline for greater than 100 ms. (Inset) Integrated histogram of pore conductance (see ref. 5). The time axis is defined as the time that a pore spends in a state within a given conductance interval, combining all fusion pores detected above noise (50 pS). (A–C) Nystatin-containing liposomes. (D) Time-resolved fusion pore conductance calculated from admittance measurements in nystatin-containing liposomes.