Fig. 7. Agents disrupting cortical F-actin inhibited bulk membrane retrieval. A, Total uptake of tetramethylrhodamine 40 kDa dextran after 1 min of stimulation in the absence (a) or presence (b) of 20 μm LatB. These examples are projections of confocalz-series. Collected results are shown in the bar chart (bottom). The following significantly reduced bulk membrane retrieval (in μm): 20 latrunculin B, 20 cytochalasin D, 50 LY294002. Control, n = 84; latrunculin B, n = 32; cytochalasin D,n = 17; LY294002, n = 13; LY303511, n = 5. t test; **p < 0.01. Scale bar, 10 μm. B, Uptake of FM1–43 after 1 min of stimulation under normal conditions (a) and in the presence of 20 μmlatrunculin B (b) or 50 μm LY294002 (c). The example images are single confocal sections taken through the middle of the terminal. Total FM1–43 fluorescence was measured by epifluorescence (see Materials and Methods). Latrunculin B, cytochalasin D, and LY294002 did not significantly affect total membrane retrieval. Control,n = 12; latrunculin B, n = 10; cytochalasin D, n = 8; LY294002,n = 5. Scale bar, 10 μm.