Histological and histochemical studies on the rhesus monkey (Macaca mulatta) olfactory mucosa

Abstract

Detailed histochemical studies on the localization of various oxidative and dephosphorylating enzymes and esterases have been made on the olfactory mucosa of the rhesus monkey. The upper part of dendritic process and terminal rods of receptor cells and the upper part of supporting cells show high oxidative enzyme activity. The soma and infranuclear parts of receptor and supporting cells have much lower oxidative enzyme activity. The basal cells and perineural epithelial cells have high hydrolytic enzyme activity, though they show low oxidative enzyme activity. Alkaline phosphatase is localized in the olfactory axons, basal cells and perineural epithelial cells. The receptor and supporting cells contain much less adenosine triphosphatase activity than the basal cells and perineural epithelial cells. The axons of receptor cells pass between the basal cells and come out from the basal cell layer forming the olfactory nerve fasciculi, most of which are surrounded completely by flat squamous cells starting from the base of the basal cell layer. The basal cells are histochemically and cytologically related to the perineural epithelial cells covering the olfactory nerve fasciculi. Basal cells probably cannot give rise to supporting cells and are not young forms of supporting cells. The degenerating receptor cells as well as the olfactory nerve fasciculi which are not completely covered by the flat squamous cells may make the locus minoris resistentiae in the olfactory mucosa. The olfactory axons are rich in most of enzymes we have tested. They seem to be metabolically very active and both cholinergic and adrenergic in nature. The mucosal secretion covering the olfactory epithelium contains oxidative and some hydrolytic enzymes. Bowman's glands show high activity for most enzymes except cholinesterases.