Figure 6.

DCVs undergo regulated exocytosis. (A) The temporal distribution of the fusion events of NPY-mRFP–positive DCVs in astrocytes cotransfected with REST/DBD-GFP and treated with 5 µM ionomycin at time 0. Each individual histogram represents the number of fusion events detected during a 200-ms-long frame in eight astrocytes. Each point of the black line reports the number of discharge events occurring in 10 s. (B) The mean kinetics of the NPY-mRFP fluorescence intensity in the course of single-discharge events (n = 8). Upon fusion, the fluorescence of puncta (inner circles) fades out with the concomitant increase of fluorescence in the external annuli (see scheme on the right), which then rapidly dissolve. The image line on the bottom illustrates the subsequent steps of a typical discharge event. In this line, numbers are in milliseconds. Bars: (B, top) 2 µm; (B, bottom) 1 µm. A.U., arbitrary unit.