5-HT2A receptor

HTR2A
Identifiers
Aliases	HTR2A, 5-HT2A, HTR2, 5-hydroxytryptamine receptor 2A
External IDs	OMIM: 182135 MGI: 109521 HomoloGene: 68073 GeneCards: HTR2A
Gene location (Human) Chr. Chromosome 13 (human)[1] Band 13q14.2 Start 46,831,546 bp[1] End 46,897,076 bp[1]
RNA expression pattern Bgee Human Mouse (ortholog) Top expressed in middle temporal gyrus frontal pole Brodmann area 23 Brodmann area 10 Brodmann area 46 endothelial cell orbitofrontal cortex superior frontal gyrus postcentral gyrus entorhinal cortex n/a More reference expression data BioGPS More reference expression data
Gene ontology Molecular function 1-(4-iodo-2,5-dimethoxyphenyl)propan-2-amine binding G protein-coupled receptor activity virus receptor activity signal transducer activity G-protein alpha-subunit binding G protein-coupled serotonin receptor activity serotonin binding neurotransmitter receptor activity protein binding protein-containing complex binding Cellular component cytoplasm integral component of membrane cytosol cell projection membrane cell body fiber integral component of plasma membrane dendritic shaft axon neuronal cell body caveola cytoplasmic vesicle plasma membrane dendrite glutamatergic synapse integral component of postsynaptic membrane integral component of presynaptic membrane Biological process detection of mechanical stimulus involved in sensory perception of pain release of sequestered calcium ion into cytosol regulation of dopamine secretion phospholipase C-activating serotonin receptor signaling pathway urinary bladder smooth muscle contraction positive regulation of MAP kinase activity behavioral response to cocaine positive regulation of cytosolic calcium ion concentration positive regulation of kinase activity positive regulation of phosphatidylinositol biosynthetic process human ageing cellular calcium ion homeostasis cell death memory activation of phospholipase C activity detection of temperature stimulus involved in sensory perception of pain protein localization to cytoskeleton sleep positive regulation of vasoconstriction positive regulation of cell population proliferation negative regulation of potassium ion transport positive regulation of ERK1 and ERK2 cascade artery smooth muscle contraction positive regulation of peptidyl-tyrosine phosphorylation viral entry into host cell phosphatidylinositol 3-kinase signaling sensory perception of pain temperature homeostasis viral process positive regulation of fat cell differentiation positive regulation of glycolytic process negative regulation of synaptic transmission, glutamatergic signal transduction chemical synaptic transmission serotonin receptor signaling pathway phospholipase C-activating G protein-coupled receptor signaling pathway G protein-coupled receptor signaling pathway animal behaviour regulation of synaptic vesicle exocytosis G protein-coupled receptor signaling pathway, coupled to cyclic nucleotide second messenger Sources:Amigo / QuickGO
Orthologs Species Human Mouse Entrez 3356 15558 Ensembl ENSG00000102468 ENSMUSG00000034997 UniProt P28223 P35363 RefSeq (mRNA) NM_001165947 NM_000621 NM_001378924 NM_172812 RefSeq (protein) NP_000612 NP_001159419 NP_001365853 NP_766400 Location (UCSC) Chr 13: 46.83 – 46.9 Mb n/a PubMed search [2] [3]
Wikidata
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The 5-HT_2A receptor is a subtype of the 5-HT₂ receptor that belongs to the serotonin receptor family and is a G protein-coupled receptor (GPCR).^[4] The 5-HT_2A receptor is a cell surface receptor,^[5] but has several intracellular locations.^[6]

Like all 5-HT₂ receptors, the 5-HT_2A receptor is G_q/G₁₁-protein coupled. This is the main excitatory receptor subtype among the GPCRs for serotonin, although 5-HT_2A may also have an inhibitory effect^[7] on certain areas such as the visual cortex and the orbitofrontal cortex.^[8] This receptor was first noted for its importance as a target of serotonergic psychedelic drugs such as LSD and psilocybin mushrooms. Later it came back to prominence because it was also found to be mediating, at least partly, the action of many antipsychotic drugs, especially the atypical ones.

Downregulation of post-synaptic 5-HT_2A receptor is an adaptive process provoked by chronic administration of selective serotonin reuptake inhibitors (SSRIs) and atypical antipsychotics. Suicidal and otherwise depressed patients have had more 5-HT_2A receptors than normal patients. These findings suggest that post-synaptic 5-HT_2A overdensity is involved in the pathogenesis of depression.^[9]

Paradoxical down-regulation of 5-HT_2A receptors can be observed with several 5-HT_2A antagonists.^[10] Thus, instead of tolerance, reverse-tolerance would be expected from 5-HT_2A antagonists. However, there is at least one antagonist at this site which has been shown to up-regulate 5-HT_2A receptors.^[10][11] Additionally, a couple of other antagonists may have no effect on 5-HT_2A receptor number.^[12] Nevertheless, upregulation is the exception rather than the rule. Neither tolerance nor rebound is observed in humans with regard to the slow-wave sleep (SWS) promoting effects of 5-HT_2A antagonists.^[13]