PACAP expression in the adult olfactory epithelium. A, PACAP-processing schematic. Rat ProPACAP is cleaved to yield the glycine-extended peptide PACAP(1–38)-Gly. PAM converts this intermediate into the final amidated product PACAP38, which is specifically recognized by the antibody. PACAP27 can be produced in certain cells by endoproteolytic cleavage at an additional amidation site within ProPACAP. B, PACAP expression. Adult rat olfactory epithelium (Bouin's fixed) was probed with antibody specific for amidated PACAP38. High levels of expression are apparent in the basal cells (arrow), as well as the neuronal region of the olfactory epithelium. The dotted line represents the separation between olfactory epithelium and lamina propria. C, PACAP in basal cells. High-magnification view of PACAP38-stained basal cells.D, Immunodepleted PACAP38 antiserum yielding no staining of the olfactory epithelium. E, In situhybridization using an antisense probe specific for proPACAP.F, In situ specificity control. The sense probe yielded no staining. G, PACAP38 immunostaining of E13 rat olfactory epithelium. H, Immunofluorescent staining of adult olfactory epithelium with PAC1 receptor antibody. Asterisks mark immunostaining in clusters of basally positioned cells; thedotted line indicates the separation between olfactory epithelium and lamina propria. I, Immunodepleted PACAP38 antiserum yielding no staining of adult olfactory epithelium. Scale bars: G, 50 μm; B, E, F, H, I, 25 μm; C, D, 12.5 μm.
