Figure 3.

Fractional fluorescence change (ratio of change in intravesicular fluorescence to extravesicular fluorescence of calcein transport as a result of exposure to unipolar (red, n = 9), bipolar with no interpulse delay (blue, n = 10), and bipolar with 50-ns interpulse delay (gray, n = 4)). Trains of 40 pulses (45 MV/m field strength and 2 ns duration) were delivered at a 1-kHz repetition rate 60 and 120 s into the recording. Error bars show standard error of the mean. (Note that the first and second phases of a 2 ns bipolar pulse are each 2 ns in duration.) The inset shows the transition at the first pulse train exposure. Vesicles that are not exposed to the electric field are also shown (n = 7). To see this figure in color, go online.