Fig. 3. Distribution of putative release sites for GABA on the salivary gland complex. Whole-mount preparations of salivary glands were stained with anti-GABA (green), anti-synapsin (red) and AlexaFluor488-phalloidin (blue), and imaged by confocal microscopy. Broken-lined rectangles outline the areas that are shown at higher magnification in the insets on the upper right of each image. Putative release sites for GABA are labeled by anti-GABA and anti-synapsin and are indicated by yellow staining in the composite images on the right. Red foci on the composite images may represent release sites for other neurotransmitters. (A–C) Putative release sites for GABA on an acinar lobule. Some putative GABA release sites (open arrowheads) are juxtaposed, others (arrowheads) reside at distance to release sites for other neurotransmitters. (D–F) Putative release sites for GABA in a nerve that interlinks acinar lobules. Most putative release sites for GABA (arrowheads) keep some distance to release sites for other neurotransmitters. Bars A–F, 25 µm.