Olfactory receptor (OR)

Olfactory receptors are a large family of G protein-coupled receptors responsible for detecting odorant molecules within the nasal epithelium. Each olfactory receptor consists of seven transmembrane domains forming an extracellular binding pocket that recognizes diverse volatile chemicals based on their shape and chemical properties. Upon ligand binding, these proteins undergo conformational changes that activate intracellular signaling pathways via specific G proteins—primarily Golf—which leads to neuronal depolarization and transmission of smell information to the brain. While best known for their role in olfaction, many olfactory receptors are also expressed outside the nose where they may participate in additional physiological processes; dysregulation has been implicated in some disease states including neurodegeneration. Structural studies reveal unique features distinguishing them from other class A GPCRs—such as specialized ligand-binding pockets conferring high selectivity—and highlight ongoing challenges due to low natural abundance and dynamic conformations.[1][4][7][9]

Other names

Odorant receptorOR (generic abbreviation)Chemosensory receptor

Drugs or ligands targeting olfactory receptors typically act as agonists by binding to the extracellular pocket of the seven-transmembrane domain structure. This induces conformational changes that activate intracellular G proteins, leading to second messenger signaling cascades such as cAMP production and subsequent ion channel opening and neuronal depolarization[4][7].