Histamine H4 Receptor: A Novel Therapeutic Target for Immune and Allergic Responses

Histamine is a biomolecular compound located in various parts of body. It participated in various important cellular activities associated with allergy and asthma. This magic bio-molecule is directly and indirectly involved in various biochemical reactions through G-protein couple receptors. Various histamine receptors and their unexplored biochemical activities attracted many biologists in last few decades. A surprising discovery of histamine H-4 receptor was done when scientists worked on histamine H-3 receptor in brain cells. The binding pocket of histamine H4 differs by transmembrane domains (TM3, TM5 and TM6) from histamine H-3-sub type. In this review, we enlightened various functions of histamine H-4 receptor and use of histamine H-4 receptor antagonists in autoimmune diseases, allergic responses, inflammatory responses, and in superoxide generation which are helpful to establish H-4 receptor antagonists as newer anti histamines.