5HT2A receptor is one of the several different receptors for 5-hydroxytryptamine (serotonin), a biogenic hormone that functions as a neurotransmitter, a hormone, and a mitogen. 5HT2A receptor belongs to the G-protein coupled receptor 1 family and mediates its action by association with G proteins that activate a phosphatidylinositol-calcium second messenger system. This receptor is involved in tracheal smooth muscle contraction, bronchoconstriction, and control of aldosterone production. 5HT2A receptor is an integral membrane protein which localizes to the post-synaptic thickening of axo-dendritic synapses. 5HT2A receptor protein contains a PDZ domain-binding motif which is involved in the interaction with INADL, CASK, APBA1, DLG1 and DLG4.