Expression of transient receptor potential vanilloid (TRPV) families 1, 2, 3 and 4 in the mouse olfactory epithelium

We investigated the expression of transient receptor potential vanilloid (TRPV)-1-4 in the mouse olfactory epithelium (OE) in comparison to its expression in respiratory epithelium. CBA/J mice were used. The localization of TRPV-1, -2, -3 and -4 in the nasal mucosa was investigated using immunohistochemistry and a double staining study for TRPV-1 and -2 and SP was also carried out. TRPV-1-4, were expressed variably in the OE with a diffuse pattern in lamina propria, and were expressed in respiratory epithelium with strong positive expression in glandular cells of lamina propria. The double-staining study revealed coexpression of TRPV-1 and -2 and substance P (SP) in the trigeminal nerve fibers of the OE. Coexpression of TRPV-1 and SP was marked around the blood vessels and seromucinous gland of respiratory epithelium while TRPV-2 showed no co-localization. TRPV-1-4 were found to be localized in the mouse OE and respiratory epithelium. Our results suggest that TRPVs may play multiple roles in the OE, contributing to olfactory adaptation, olfactory/trigeminal interactions in nasal chemoreception and OE homeostasis; they may also be involved in olfactory transduction as well as olfactory dysfunction secondary to sinonasal inflammatory disease. TRPVs in respiratory mucosa may play a significant role in nasal nociception, ciliary movement and the regulation of mucous secretion.