The 5-HT2A receptor is a subtype of the 5-HT2 receptor that belongs to the serotonin receptor family and is a G protein-coupled receptor (GPCR). The 5-HT2A receptor is a cell surface receptor, but has several intracellular locations.
The 5-HT2 receptors are a subfamily of 5-HT receptors that bind the endogenous neurotransmitter serotonin (5-hydroxytryptamine, 5-HT). The 5-HT2 subfamily consists of three G protein-coupled receptors (GPCRs) which are coupled to Gq/G11 and mediate excitatory neurotransmission, including 5-HT2A, 5-HT2B, and 5-HT2C. For more information, please see the respective main articles of the individual subtypes:
5-Hydroxytryptamine receptor 2B (5-HT2B) also known as serotonin receptor 2B is a protein that in humans is encoded by the HTR2B gene. 5-HT2B is a member of the 5-HT2 receptor family that binds the neurotransmitter serotonin (5-hydroxytryptamine, 5-HT). Like all 5-HT2 receptors, the 5-HT2B receptor is Gq/G11-protein coupled, leading to downstream activation of phospholipase C.
RS-127445 is a drug which acts as a potent and selective antagonist at the serotonin 5-HT2B receptor, with around 1000 times selectivity over the closely related 5-HT2A and 5-HT2C receptors. The role of the 5-HT2B receptor in the body is still poorly understood, and RS-127445 has been a useful tool in unravelling the function of the various systems in which this receptor is expressed.
BW-723C86 is a tryptamine derivative drug which acts as a 5-HT2B receptor agonist. It has anxiolytic effects in animal studies, and is also used for investigating the function of the 5-HT2B receptor in a range of other tissues.
AL-38022A is an indazole derivative drug which is one of a range of similar drugs developed for scientific research and with some possible clinical applications. It acts as a potent and selective agonist for the 5-HT2 family of serotonin receptors, with highest binding affinity for the 5-HT2C subtype and around four times less affinity for 5-HT2A and 5-HT2B. In drug discrimination tests on animals, it fully substituted for both DOM and 5-MeO-DMT.
AL-37350A (4,5-DHP-AMT) is a tricyclic tryptamine derivative which acts as a potent and selective agonist for the serotonin receptor 5-HT2A, with a Ki of 2.0 nM, and moderate selectivity over the related 5-HT2B and 5-HT2C receptors. It has been shown to have ocular hypotensive activity in animal models, suggesting it may be useful for the treatment of glaucoma.
SDZ SER-082 is a drug which acts as a mixed antagonist for the 5-HT2B and 5-HT2C serotonin receptors, with good selectivity over other serotonin receptor subtypes and slight preference for 5-HT2C over 5-HT2B. It has been used in animal studies into the behavioural effects of the different 5-HT2 subtypes, and how they influence the effects of other drugs such as cocaine.
SB-215505 is a drug which acts as a potent and selective antagonist at the serotonin 5-HT2B receptor, with good selectivity over the related 5-HT2A and 5-HT2C receptors. It is used in scientific research into the function of the 5-HT2 family of receptors, especially to study the role of 5-HT2B receptors in the heart, and to distinguish 5-HT2B-mediated responses from those produced by 5-HT2A or 5-HT2C.
Serotonin antagonist and reuptake inhibitors (SARIs) are a class of drugs used mainly as antidepressants, but also as anxiolytics and hypnotics. They act by antagonizing serotonin receptors such as 5-HT2A and inhibiting the reuptake of serotonin, norepinephrine, and/or dopamine. Additionally, most also antagonize α1-adrenergic receptors. The majority of the currently marketed SARIs belong to the phenylpiperazine class of compounds.
4-Substituted-2,5-dimethoxyamphetamines (DOx) is a chemical class of substituted amphetamine derivatives featuring methoxy groups at the 2- and 5- positions of the phenyl ring, and a substituent such as alkyl or halogen at the 4- position of the phenyl ring. Most compounds of this class are potent and long-lasting psychedelic drugs, and act as highly selective 5-HT2A, 5-HT2B, and 5-HT2C receptor partial agonists. A few bulkier derivatives such as DOAM have similarly high binding affinity for 5-HT2 receptors but instead act as antagonists, and so do not produce psychedelic effects though they retain amphetamine-like stimulant effects.
VER-3323 is a drug which acts as a selective agonist for both the 5-HT2B and 5-HT2C serotonin receptor subtypes, with moderate selectivity for 5-HT2C, but relatively low affinity for 5-HT2A. It has potent anorectic effects in animal studies.
SB-206553 is a drug which acts as a mixed antagonist for the 5-HT2B and 5-HT2C serotonin receptors. It has anxiolytic properties in animal studies and interacts with a range of other drugs. It has also been shown to act as a positive allosteric modulator of α7 nicotinic acetylcholine receptors. Modified derivatives of SB-206553 have been used to probe the structure of the 5-HT2B receptor.
Glemanserin (INN) is a drug which acts as a potent and selective 5-HT2A receptor antagonist. The first truly selective 5-HT2A ligand to be discovered, glemanserin resulted in the development of the widely used and even more potent and selective 5-HT2A receptor antagonist volinanserin (MDL-100,907), which is a fluorinated analogue. Though it was largely superseded in scientific research by volinanserin, glemanserin was investigated clinically for the treatment of generalized anxiety disorder. However, it was ultimately found to be ineffective and was not marketed.
5-HT2C receptor agonists are a class of drugs that activate 5-HT2C receptors. They have been investigated for the treatment of a number of conditions including obesity, psychiatric disorders, sexual dysfunction and urinary incontinence.
O-4310 (1-isopropyl-6-fluoro-psilocin) is a tryptamine derivative developed by Organix Inc which acts as a serotonin receptor agonist. It is claimed to have an EC50 of 5nM at 5-HT2A with 89% efficacy vs 5-HT, and 100x selectivity over 5-HT2C, while being apparently inactive at the 5-HT2B antitarget.
25CN-NBOH is a compound indirectly derived from the phenethylamine series of hallucinogens, which was discovered in 2014 at the University of Copenhagen. This compound is notable as one of the most selective agonist ligands for the 5-HT2A receptor yet discovered, with a pKi of 8.88 at the human 5-HT2A receptor and with 100x selectivity for 5-HT2A over 5-HT2C, and 46x selectivity for 5-HT2A over 5-HT2B. A tritiated version of 25CN-NBOH has also been accessed and used for more detailed investigations of the binding to 5-HT2 receptors and autoradiography.
CP-132,484 is a tryptamine derivative which acts as a potent and selective agonist for the 5-HT2 family of serotonin receptors. It has reasonable selectivity for 5-HT2A and 5-HT2C subtypes over 5-HT2B, but is only slightly selective for 5-HT2A over 5-HT2C. This compound and several related analogues have been shown to have ocular hypotensive activity in animal models, suggesting they may be useful for the treatment of glaucoma.
CPD-1 (LS-193743) is a drug with a benzofuranyl piperazine structure, which acts as a potent and selective agonist for the 5-HT2 receptor family, with highest affinity and full agonist efficacy at the 5-HT2C subtype, and lower affinity and partial agonist action at the 5-HT2A and 5-HT2B subtypes.
SCHEMBL5334361 is a drug which acts as an agonist at the 5-HT2 family of serotonin receptors, and was developed for the treatment of glaucoma. It is a benzazepine derivative structurally related to the anorectic drug lorcaserin. It is selective for 5-HT2A, with an EC50 of 0.4nM at 5-HT2A vs 3.9nM at 5-HT2C and a much lower affinity of 417nM at 5-HT2B.
