Localization and function of histamine H3receptor in the nasal mucosa

BACKGROUND: Histamine is an important chemical mediator of allergic rhinitis (AR). Histamine H(3) receptors (H(3)R) are located on cholinergic and NANC neurons of the myenteric plexus, and activation of H(3)R regulates gastric acid secretion. However, little is known about the localization and function of H(3)R in the upper airway. OBJECTIVE: The objective of this study was to examine the localization and possible function of H(3)R in the nasal mucosa. METHODS: We extracted total RNA from the inferior turbinate mucosa of patients with AR. H(3)R mRNA and beta-actin mRNA were amplified by RT-PCR. We used immunohistochemistry to examine localization of H(3)R protein in the inferior turbinate mucosa excised during clinically indicated surgery. We used alcian blue/periodic acid-shiff staining to examine the effects of the H(3)R agonist (R)-alpha-methylhistamine and the H(3)R antagonist thioperamide on secretion from rat submucosal glands. RESULTS: H(3)R protein was expressed around submucosal gland cells. Thioperamide induced degranulation in the submucosal gland in the nasal septum. CONCLUSION: The present results suggest that H(3)R is localized mainly around submucosal glands, and that H(3)R plays an important role in the secretion of submucosal glands in the nose.