Figure 4

(a) Lumen view of a small area of epithelium representative of a whole mount of airway mucosa double-stained with calcitonin gene-related peptide (CGRP, red) and PGP9.5 (green). CGRP is present in terminal processes of some PNEC. Bar = 100 μm. Boxed area (right): Side projection of the PNEC where two lumen-directed processes and the long stem of the cell body (green) ascend to the apical epithelium. From this view the right process is strongly CGRP positive. Bar = 20 μm. (b) Wholemount of airway mucosa double-stained for CGRP (red) and PGP 9.5 (green) showing diverse morphology of PNEC. Upper panel is the lumen view, middle is a rotated through 45 degrees and the lower through 90 degrees. From left to right: A pair of PNEC with CGRP in the processes. The next two have fine processes that arise from the cell body and the apex of the stem. The right hand pair of PNEC exhibits branching of the main stem close to the lumen. Bar = 50 μm.