Figure 6. PAR agonists stimulate secretion of quinacrine-labelled granules.

Calu-3 cell mucin granules were loaded with quinacrine (10 μm, 20 min at 37°C). Cells were mounted in a confocal microscope and real-time images of the DIC/Nomarski illumination (grey) and fluorescence (green) channels acquired every 30 s (see Methods). Cells were challenged with vehicle (control), 50 nm thrombin, 100 μm PAR1P, or 100 μm PAR2P. A, overlay of the DIC and fluorescence confocal images of quinacrine-labelled Calu-3 cells in control conditions; bar = 10 μm. B, representation of the change in fluorescence intensity associated with 1 μm granules after 5 min incubation with vehicle or PAR agonists (n= 3; mean ±s.e.m.; *P < 0.01).