Localization and function of histamine H3 receptor in the nasal mucosa

Background Histamine is an important chemical mediator of allergic rhinitis (AR). Histamine H₃ receptors (H₃R) are located on cholinergic and NANC neurons of the myenteric plexus, and activation of H₃R regulates gastric acid secretion. However, little is known about the localization and function of H₃R in the upper airway.
Objective The objective of this study was to examine the localization and possible function of H₃R in the nasal mucosa.
Methods We extracted total RNA from the inferior turbinate mucosa of patients with AR. H₃R mRNA and β-actin mRNA were amplified by RT-PCR. We used immunohistochemistry to examine localization of H₃R 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 H₃R agonist (R)-α-methylhistamine and the H₃R antagonist thioperamide on secretion from rat submucosal glands.
Results H₃R protein was expressed around submucosal gland cells. Thioperamide induced degranulation in the submucosal gland in the nasal septum.
Conclusion The present results suggest that H₃R is localized mainly around submucosal glands, and that H₃R plays an important role in the secretion of submucosal glands in the nose.