Suppression of Histamine H1 Receptor Gene Expression by Antihistamines with Inverse Agonist Activities

Allergic rhinitis is an incurable disease whose prevalence rate is over 30% in Japan. Antihistamines are first‐choice drugs for the therapy of the disease. However, sole treatment of antihistamine is not enough to obtain satisfactory control. We elucidated histamine‐induced histamine H1 receptor gene expression as a pathological mechanism of allergic rhinitis. Treatment of epinastine, an antihistamine, to allergic rhinitis patients showed alleviation of nasal symptoms and correlated suppression of histamine H1 receptor mRNA elevation in nasal mucosa. We observed inverse agonist activities in some antihistamines. Suppression of inositol phosphates accumulation and suppression of histamine H1 receptor gene expression showed good correlation. These results suggested that antihistamines with inverse agonist activities have advantage for the therapy of allergic rhinitis.Support or Funding InformationResearch Grant from The Osaka Medical Research Foundation for Intractable Diseases