title: Histamine H₄ receptor: a novel target for inflammation therapy.
abstract: Histamine, a low molecular weight amine has been extensively studied for its various pharmacological profiles. Until recently histamine was thought to act on three receptors - H₁, H₂ and H₃. Merely a decade back, sequencing of human genome has revealed a new histamine receptor - H₄ receptor. This 390 amino acid sequenced receptor has around 38% homology with histamine H₃ receptor besides; the pharmacological profile of the protein is quite different from other histamine receptors. H₄ receptor is mainly expressed in mast cells and leukocytes and involves various physiological functions related to inflammation and allergy. Potent selective H₄ receptor agonists and antagonists have been synthesized and in vivo studies have indicated their action on H₄ receptor. In this review, structure, expression, homology sequence of H₄ receptor among the different species has been documented. Further, structure activity relationship (SAR) of H₄ ligands on the basis of their nucleus has been discussed in depth. In addition, anti-inflammatory effects of H₄ receptor antagonists, with special emphasis to JNJ7777120, a selective H₄ receptor antagonist have been focused exhaustively.
authors.affiliation: Pharmaceutical Chemistry Research Laboratory, Department of Pharmaceutics, Institute of Technology, Banaras Hindu University, Varanasi- 221005, India.
authors.forename: C
authors.initials: C
authors.lastname: Saravanan
authors.forename: S K
authors.initials: SK
authors.lastname: Bharti
authors.forename: S
authors.initials: S
authors.lastname: Jaggi
authors.forename: S K
authors.initials: SK
authors.lastname: Singh
mesh_terms: D000893:Anti-Inflammatory Agents / Q000494:pharmacology / Q000627:therapeutic use*; D006801:Humans; D007249:Inflammation / Q000188:drug therapy*; D007962:Leukocytes / Q000187:drug effects / Q000276:immunology; D008407:Mast Cells / Q000187:drug effects / Q000276:immunology; D043562:Receptors, G-Protein-Coupled / Q000378:metabolism*; D011968:Receptors, Histamine / Q000378:metabolism*; D000074040:Receptors, Histamine H4
chemical_list: D000893:Anti-Inflammatory Agents; C418607:HRH4 protein, human; D043562:Receptors, G-Protein-Coupled; D011968:Receptors, Histamine; D000074040:Receptors, Histamine H4