Figure 2.

(a). High power projection of two PNEC and associated nerves imaged from the lumen and stained with the neural marker, protein gene product 9.5 (PGP 9.5). To reveal the shape of the cell body and the diverse structure of its processes the data set has been rotated to enable viewing the PNEC from the side. The upper panel is the conventional view from the lumen surface. The middle panel is rotated at 45 deg, and the lower panel shows the side view at 90 degrees. Nerves are present in close apposition to the PNEC. Bar = 20 μm. (b & c) Projections of typical flask-like PNEC stained with PGP 9.5 and imaged from the lumen over the edge of a mucosal fold. The cell bodies are seen from their sides (thus a cut off line for the surface of the epithelium with the lumen is not clearly seen). Processes of varying morphology arise from the cell bodies and varicose nerves are present near the base and apex of the PNEC with individual nerve fibers rising through the epithelium. The apex of the cell is brightly stained in (b). Bars = 10 μm. (d) Four PNEC viewed from a flat area of the airway lumen showing dendritic-like processes. This low power projection extends through a depth of 50 μm and includes nerves that lie below the basement membrane.