Histamine Receptor H1 (HRH1)

The H1 receptor is a histamine receptor belonging to the family of G-protein-coupled receptors. This receptor which is activated by the biogenic amine histamine is expressed throughout the body, specifically in smooth muscles, on vascular endothelial cells, in the heart, and in the central nervous system. The H1 receptor is linked to an intracellular G-protein (Gq) that activates phospholipase C and the phosphatidylinositol (PIP2) signaling pathway. Based on the number of drugs available on market it is the most clinically important molecular drug target.The production of prostaglandin E2 synthase induces the release of histamine from neurons, causing systemic vasodilation, along with increased cell permeability due to its action on H1 receptors.