Inhibition of ASM activity with DPA allows rapid and sustained influx of FM1-43 into SLO-permeabilized NRK cells. NRK cells were preincubated with 100 ng/ml SLO at 4°C and transferred to a live imaging chamber at 37°C, followed by the addition of FM1-43 and time-lapse confocal imaging for 4 min at 1 frame/3 s. (A) Ca2+-free DME and FM1-43 were added 10 s before the beginning of the video. (B) Ca2+-containing DME and FM1-43 were added 10 s before the beginning of the video to nontreated cells. (C) Ca2+-containing DME and FM1-43 were added 10 s before the beginning of the video to DPA-treated cells. This video is displayed at 8 frames/s. Bar, 18 µm.
