Since its identification by Sir Henry Dale a century ago, histamine has become one of the most important multifunctional biogenic amines in the field of biomedicine. The pharmacologic effects of histamine are mediated through four types of membrane histamine receptors; H1R, H2R, H3R and H4R, which are all heptahelical G-protein-coupled receptors. It has been known to play the broadest spectrum of activities in various physiological and pathological conditions including cell proliferation, differentiation, hematopoiesis, embryonic development, regeneration, wound healing, aminergic...