Immunohistochemical localization of histamine receptor subtypes in human inferior turbinates.

Histamine is an important chemical mediator in allergic rhinitis and plays an important role in eliciting the nasal symptoms of the disorder. However, the immunohistochemical localization of histamine receptor subtypes (H1R, H2R, H3R, and H4R) in human nasal mucosa is unknown. There are also no prior studies of H3R and H4R in human nasal mucosa. The objective of this study was to examine the distribution of histamine receptor subtypes in the human inferior turbinates by an immunohistochemical method. H1R was localized primarily in the epithelium, vessels, and nerves. H2R was localized primarily in the epithelium and the glands. H3R and H4R were clearly distributed on the nerves. In addition, H1R, H3R, and H4R were clearly localized on the same nerves. This result indicates that H1R, H3R, and H4R adjoin and regulate each other in the same nerves. All histamine receptor subtypes may play some role in patients with allergic rhinitis.