Fig. 2. Disappearance of patches after removal of cAMP. Cells were stimulated with 1 µM cAMP for 240 seconds (first 60 seconds shown), washed with buffer for 30 seconds (from 240-270 seconds), and then re-stimulated with 1 µM cAMP for 30 seconds. (A) The response at the boundary of a typical cell. (B) The cell was washed with buffer for only 10 seconds. (C) The means and standard deviations of the fluorescence intensity of the cytosol from 20 cells; the black line shows the intensity for the wash with buffer for 30 seconds, and the green line for 10 seconds. The dotted line represents a first-order decay of the fluorescence intensity with a latency time (tlat) and a half-life (t1/2).