HTR2A
Description
The HTR2A (5-hydroxytryptamine receptor 2A) is a protein-coding gene located on chromosome 13.
The 5-HT2A receptor is a subtype of the 5-HT2 receptor, part of the serotonin receptor family and a G protein-coupled receptor (GPCR). It is located on the cell surface but can also be found in various intracellular locations. As with all 5-HT2 receptors, the 5-HT2A receptor is Gq/G11-protein coupled. This makes it the primary excitatory receptor subtype among GPCRs for serotonin, though it can also have inhibitory effects in specific areas, such as the visual cortex and orbitofrontal cortex. The receptor was initially recognized for its importance as a target for serotonergic psychedelic drugs like LSD and psilocybin mushrooms. It later gained further prominence due to its role in mediating, at least partially, the action of many antipsychotic drugs, especially atypical antipsychotics. Downregulation of post-synaptic 5-HT2A receptors is an adaptive response triggered by chronic administration of selective serotonin reuptake inhibitors (SSRIs) and atypical antipsychotics. Suicidal and otherwise depressed patients have been observed to have higher levels of 5-HT2A receptors than normal patients, suggesting that post-synaptic 5-HT2A overdensity is involved in the development of depression. Paradoxically, 5-HT2A receptor down-regulation can occur with several 5-HT2A antagonists.
The HTR2A gene encodes a G protein-coupled receptor for 5-hydroxytryptamine (serotonin). It also acts as a receptor for various drugs and psychoactive substances, including mescaline, psilocybin, 1-(2,5-dimethoxy-4-iodophenyl)-2-aminopropane (DOI), and lysergic acid diethylamide (LSD). Ligand binding triggers signaling via G proteins and modulates downstream effectors. Beta-arrestin family members inhibit signaling via G proteins and activate alternative signaling pathways. Signaling activates phospholipase C and a phosphatidylinositol-calcium second messenger system, which modulates phosphatidylinositol 3-kinase activity and promotes Ca(2+) ion release from intracellular stores. HTR2A influences neural activity, perception, cognition, and mood. It regulates behavior, including responses to anxiogenic situations and psychoactive substances. Additionally, it plays a role in intestinal smooth muscle contraction and may contribute to arterial vasoconstriction.
HTR2A is also known as 5-HT2A, HTR2.
