Immunohistochemical and electron microscopic studies of substance P in guinea pig nasal glands.

The distribution of substance P-like immunoreactive (SP-IR) nerve endings in the nasal gland of the guinea pig was studied by using histochemical techniques to detect mucous glycoprotein and immunohistochemical techniques for SP, in combination with electron microscopy. Most nasal glands were negative for both AB and periodic acid-Schiff (PAS) staining. The SP-IR nerve fibers were found to form a network around these glands. The SP-IR nerve endings were located in the region between interdigitated cytoplasmic folds of acinar cells and along the cell surface, as well as in the intercellular spaces of proximal ducts. The acini which closely contacted with SP-IR nerve endings were serous in type. Our results suggest that substance P may contribute to the regulation of serous gland secretion in the guinea pig nasal mucosa.