Academy of Pharmaceutical Sciences 28 th Annual Conference

®® ® ® ) have been successfully used for many years for the treatment of allergic conditions and gastric ulcers, respectively. Moreover, currently a lot of attention in the pharmaceutical industry is directed towards the therapeutic use of H 3 antagonist for e.g cognitive disorders and obesity. And then there were four…… Following the sequencing of the human genome, data mining efforts have revealed the existence of a new histamine receptor with high expression levels in mast cells and leukocytes. Using the sequence information of the human H 3 receptor, several groups independently identified a homologous GPCR sequence in the human genome sequence databases. The H 4 receptor is a 390 amino acid protein and this new GPCR is expressed predominantly in bone marrow, eosinophils and mast cells. Moreover, the histamine H 4 receptor shows a clearly distinct pharmacological profile. At this moment the first selective compounds have now been reported and are being made available for pharmacologists/immunologists. Initial in vivo experiments with H 4 receptor antagonists suggest a role for the H 4 receptor in inflammatory conditions.