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-Methoxytryptamine (5-MT), also known as mexamine, is a tryptamine derivative closely related to the neurotransmitters serotonin and melatonin. 5-MT has been shown to occur naturally in the body in low levels. It is biosynthesized via the deacetylation of melatonin in the pineal gland.
The 5-HT1 receptors are a subfamily of the 5-HT serotonin receptors that bind to the endogenous neurotransmitter serotonin (also known as 5-hydroxytryptamine, or 5-HT). The 5-HT1 subfamily consists of five G protein-coupled receptors (GPCRs) that share 40% to 63% overall sequence homology, including 5-HT1A, 5-HT1B, 5-HT1D, 5-HT1E, and 5-HT1F. Receptors of the 5-HT1 type, specifically, the 5-HT1A and 5-HT1D receptor subtypes, are present on the cell bodies. Receptors of the 5-HT1 type, specifically, the 5-HT1B and 5-HT1D receptor subtypes, are also present on the nerve terminals. These receptors are broadly distributed throughout the brain and are recognized to play a significant part in regulating synaptic levels of 5-HT.
5-hydroxytryptamine (serotonin) receptor 1F, also known as HTR1F is a 5-HT1 receptor protein and also denotes the human gene encoding it.
5-Carboxamidotryptamine (5-CT) is a tryptamine derivative closely related to the neurotransmitter serotonin.
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 4x 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 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.
1-(1-Naphthyl)piperazine (1-NP) is a drug which is a phenylpiperazine derivative. It acts as a non-selective, mixed serotonergic agent, exerting partial agonism at the 5-HT1A, 5-HT1B, 5-HT1D, 5-HT1E, and 5-HT1F receptors, while antagonizing the 5-HT2A, 5-HT2B, and 5-HT2C receptors. It has also been shown to possess high affinity for the 5-HT3, 5-HT5A, 5-HT6, and 5-HT7 receptors, and may bind to 5-HT4 and the SERT as well. In animals it produces effects including hyperphagia, hyperactivity, and anxiolysis, of which are all likely mediated predominantly or fully by blockade of the 5-HT2C receptor.
5-Methoxy-7,N,N-trimethyltryptamine (5-MeO-7,N,N-TMT, 5-MeO-7-TMT), is a tryptamine derivative which acts as a partial agonist at the 5-HT2 serotonin receptors, with an EC50 of 63.9 nM and an efficacy of 66.2% at 5-HT2A (vs 5-HT), and weaker activity at 5-HT2B and 5-HT2C. In animal tests, both 7,N,N-TMT and 5-MeO-7,N,N-TMT produced behavioural responses similar to those of psychedelic drugs such as DMT and 5-MeO-DMT, but compounds with larger 7-position substituents such as 7-ethyl-DMT and 7-bromo-DMT did not produce psychedelic-appropriate responding despite high 5-HT2 receptor binding affinity, suggesting these may be antagonists or weak partial agonists for the 5-HT2 receptors. The related compound 7-MeO-MiPT (cf. 5-MeO-MiPT) was also found to be inactive, suggesting that the 7-position has poor tolerance for bulky groups at this position, at least if agonist activity is desired.
7,N,N-trimethyltryptamine (7-methyl-DMT, 7-TMT), is a tryptamine derivative which acts as an agonist of 5-HT2 receptors. In animal tests, both 7-TMT and its 5-methoxy derivative 5-MeO-7-TMT produced behavioural responses similar to those of psychedelic drugs such as DMT, but the larger 7-ethyl and 7-bromo derivatives of DMT did not produce psychedelic responses despite having higher 5-HT2 receptor affinity in vitro (cf. DOBU, DOAM). 7-TMT also weakly inhibits reuptake of serotonin but with little effect on dopamine or noradrenaline reuptake.
5-(Nonyloxy)tryptamine is a tryptamine derivative which acts as a selective agonist at the 5-HT1B receptor. Increasing the O-alkoxy chain length in this series gives generally increasing potency and selectivity for 5-HT1B, with highest activity found for the nonyloxy derivative, having a 5-HT1B binding affinity of 1.0 nM, and around 300-fold selectivity over the related 5-HT1A receptor.
1-(2-Dimethylaminoethyl)dihydropyrano(3,2-e)indole (4,5-DHP-DMT) is a tricyclic tryptamine derivative which acts as a potent and reasonably selective partial agonist for the serotonin receptor 5-HT2A, with a Ki of 17.0 nM, and moderate selectivity over related serotonin receptors. It has lower 5-HT2 affinity and efficacy than the related compound AL-37350A, but higher lipophilicity.
5-HO-DiPT (5-hydroxy-N,N-di-iso-propyltryptamine) is a tryptamine derivative which acts as a serotonin receptor agonist. It is primarily known as a metabolite of the better known psychoactive drug 5-MeO-DiPT, but 5-HO-DiPT has also rarely been encountered as a designer drug in its own right. Tests in vitro show 5-HO-DiPT to have high 5-HT2A affinity and good selectivity over 5-HT1A, while being more lipophilic than the related drug bufotenine (5-HO-DMT), which produces mainly peripheral effects.
LY-215,840 is an ergoline derivative drug developed by Eli Lilly, which acts as a potent and selective antagonist at the serotonin 5-HT2 and 5-HT7 receptors. It has anti-hypertensive and muscle relaxant effects in animal studies.
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.
NDTDI is a tricyclic tryptamine derivative which is thought to act as a serotonin receptor agonist, though its pharmacology has not been studied in detail. It is a structurally simplified analogue of LSD and is reported to retain similar effects, though with many times lower potency. It has been sold as a designer drug since 2016 and was first identified by a forensic laboratory in Slovenia in 2017.
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.
5F-MPMI is a tryptamine derivative which acts as a serotonin receptor agonist, selective for the 5-HT2 subtypes but with similar affinity to all three receptors, having strongest activity at 5-HT2B and weakest at 5-HT2A.
7-F-5-MeO-MET (5-MeO-7-F-MET, 5-Methoxy-7-fluoro-N-methyl-N-ethyltryptamine) is a tryptamine derivative which acts as a serotonin receptor agonist selective for the 5-HT2 subtypes, with a pEC50 of 8.71 at 5-HT2A, vs 8.25 at 5-HT2B and 7.69 at 5-HT2C. In animal tests it produced the most potent head-twitch response of a range of related fluorinated tryptamine derivatives tested, though still with slightly lower potency than psilocybin.
