Fig. 3. z-Stack profile of fluorescence intensity of double-labeled vesicles. The left side of the figure shows three optical planes (a, first; b, middle; c, last) from a stack of 40 images (total thickness 3 µm). For each focal plane a sample of three vesicles that show colocalization (yellow) of GABA_B receptor (red) and clathrin (green) is selected (white bars). The right side of the figure shows fluorescence-intensity distribution along the z-axis for each selected vesicle (green, ), (red, ).