FIGURE 4.
Formation of quinacrine vesicles. HTC cells labeled with FM4-64 and quinacrine and imaged with confocal microscopy as described under “Experimental Procedures.” A, in the continuous presence of quinacrine (green) and FM4-64 (red), no significant co-localization (yellow) is observed until 45 min (Pearson's coefficient = 0.85). Scale bar, 10 μm. B, bafilomycin A1 inhibits quinacrine vesicle formation and ATP release. First column, quinacrine; second column, FM4-64; third column, merged images. Top row, control; bottom row, postincubation with bafilomycin A1 (4 μm for 30 min). Scale bar, 10 μm. C, bulk ATP release (measured as arbitrary light units) was measured from confluent HTC cells after isotonic and hypotonic (33%) exposures in control (black circles) or after incubation with bafilomycin A1 (open circles). Each point represents mean ± S.E. for n = 7 trials each. *, basal, isotonic, and hypotonic buffer-stimulated ATP release was significantly inhibited, p < 0.01.