Figure 4.

Distribution of serotonergic nerve fibers on the salivary gland acini Whole-mounts of salivary glands were double-labeled with anti-serotonin (red) and BODIPY FL phallacidin (blue), and imaged by confocal microscopy. Each image shows the sum of 8 consecutive optical sections (inter-section distance 0.35 μm), representing a total thickness of 2.8 μm. Serotonergic fibers and fiber endings (white arrowhead) form a network on the acinar surface (a) over the peripheral cells (asterisks). The fibers extend deep into the acini (yellow arrowheads) between the central cells that are identified by short, phallotoxin-labeled microvilli (arrows) on their luminal surface. Scale bar = 50 μm