Fig. 5. Patch formation in latrunculin-A-treated cells. Cells in the perfusion chamber were incubated with 1 µM latrunculin A for 15 minutes, subsequently stimulated at t=0 seconds with 1 µM cAMP and washed with buffer at t=90 seconds. (A) The fluorescence intensity and the shape of a representative cell before and after stimulation with cAMP. (B) The fluorescence intensity at the boundary for the same cell. Before mounting the perfusion chamber, cells were overlaid with a thin layer of agarose to prevent elution of these spherical cells. The small indentations at 0 seconds, 90 seconds and 120 seconds are perfusion artefacts; at the onset of perfusion, the cover slip bends for a few seconds and cells move in the plane of focus.