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 H4 receptor was done when scientists worked on histamine H3 receptor in brain cells. The binding pocket of histamine H4 differs by transmembrane domains (TM3, TM5 and TM6) from histamine H3-sub type. In this review, we enlightened various functions of histamine H4 receptor and use of histamine H4 receptor antagonists in autoimmune diseases, allergic responses, inflammatory responses, and in superoxide generation which are helpful to establish H4 receptor antagonists as newer anti histamines.