Morphology of intraepithelial corpuscular nerve endings in the nasal respiratory mucosa of the dog

Corpuscular nerve endings in the nasal respiratory mucosa of the dog were i nvestigated by immunohistochemical staining specific for protein gene produ ct 9.5 by light and electron microscopy. In the nasal respiratory mucosa, c omplex corpuscular endings, which displayed bulbous, laminar and varicose e xpansions, were distributed on the dorsal elevated part of the nasal septum and on the dorsal nasal concha. The endings were 300-500 mu m long and 100 -250 mu m wide. Some axons gave rise to a single ending while others branch ed into 2 endings. Cryostat sections revealed that the corpuscular endings were located within the nasal respiratory epithelium. On electron microscop y, immunoreactive nerve terminals that contained organelles, including mito chondria and neurofilaments, were observed within the epithelial layer near the lumen of the nasal cavity. Some terminals contacted the goblet cell. S uch terminal regions were covered by the cytoplasmic process of ciliated ce lls and were never exposed to the lumen of the nasal cavity. These nerve en dings are probably activated by pressure changes.