Effect of histamine H3 receptor selective agonist imetit on cough and symptoms of allergic rhinitis in animal model of upper airway cough syndrome

Background Upper airway diseases (e.g. allergic rhinitis (AR)) are one of most common causes of chronic cough in subjects with negative X-ray finding. In UACS (upper airway cough syndrome), cough is strongly associated with the ongoing nasal inflammation. Effective treatment of nasal inflammation may lead to down regulation of pathologically enhanced chronic cough. Histamine plays a critical role in upper airway diseases. All known histamine receptors (H1R, H2R, H3R, and H4R) have been demonstrated in the nasal mucosa. Old generation of antihistamines (inverse agonists of H1R) are empirically used in treatment of UACS, although their clinical use is limited by their serious adverse effects. The aim of our study was to ascertain the effect of H3R selective agonist imetit known to suppress release of substance P from afferent nerves in allergic nasal inflammation on cough and symptoms of AR in an animal model.