HRH1 and allergic disease: The H1R predominantly couplesto Gαq/11 proteins and upon receptor activation progressesmainly through the inositol-phospholipid-dependent pathway with asubsequent increase in intracellular Ca2+ concentration.The H1R is widely distributed throughout the body, particularlyin immune cells, the lungs, blood vessels, and the central nervoussystem.1,2 The H1R has an established rolein allergy and inflammation and is the therapeutic target for antihistamines(e.g., loratadine and cetirizine) in the treatment of allergic rhinitis,hayfever, and urticaria.