5-HT receptors, 5-hydroxytryptamine receptors, or serotonin receptors, are a group of G protein-coupled receptor and ligand-gated ion channels found in the central and peripheral nervous systems. They mediate both excitatory and inhibitory neurotransmission. The serotonin receptors are activated by the neurotransmitter serotonin, which acts as their natural ligand.
Methysergide, sold under the brand names Deseril and Sansert, is a monoaminergic medication of the ergoline and lysergamide groups which is used in the prophylaxis and treatment of migraine and cluster headaches. It has been withdrawn from the market in the United States and Canada due to adverse effects. It is taken by mouth.
A serotonin receptor agonist is an agonist of one or more serotonin receptors. They activate serotonin receptors in a manner similar to that of serotonin, a neurotransmitter and hormone and the endogenous ligand of the serotonin receptors.
meta-Chlorophenylpiperazine (mCPP) is a psychoactive drug of the phenylpiperazine class. It was initially developed in the late-1970s and used in scientific research before being sold as a designer drug in the mid-2000s. It has been detected in pills touted as legal alternatives to illicit stimulants in New Zealand and pills sold as "ecstasy" in Europe and the United States.
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.
TCB-2 is a hallucinogen discovered in 2006 by Thomas McLean working in the lab of David Nichols at Purdue University. It is a conformationally-restricted derivative of the phenethylamine 2C-B, also a hallucinogen, and acts as a potent agonist for the 5-HT2A and 5-HT2C receptors with a Ki of 0.26 nM at the human 5-HT2A receptor. In drug-substitution experiments in rats, TCB-2 was found to be of similar potency to both LSD and Bromo-DragonFLY, ranking it among the most potent phenethylamine hallucinogens yet discovered. This high potency and selectivity has made TCB-2 useful for distinguishing 5-HT2A mediated responses from those produced by other similar receptors. TCB-2 has similar but not identical effects in animals to related phenethylamine hallucinogens such as DOI, and has been used for studying how the function of the 5-HT2A receptor differs from that of other serotonin receptors in a number of animal models, such as studies of cocaine addiction and neuropathic pain.
SB-242084 is a psychoactive drug and research chemical which acts as a selective antagonist for the 5HT2C receptor. It has anxiolytic effects, and enhances dopamine signalling in the limbic system, as well as having complex effects on the dopamine release produced by cocaine, increasing it in some brain regions but reducing it in others. It has been shown to increase the effectiveness of the selective serotonin reuptake inhibitor (SSRI) class of antidepressants, and may also reduce their side effects. In animal studies, SB-242084 produced stimulant-type activity and reinforcing effects, somewhat similar to but much weaker than cocaine or amphetamines.
RS-127445 is a drug which acts as a potent and selective antagonist at the serotonin 5-HT2B receptor, with around 1000x 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.
SB-204741 is a drug which acts as a potent and selective antagonist at the serotonin 5-HT2B receptor, with around 135x selectivity over the closely related 5-HT2C receptor, and even higher over the 5-HT2A receptor and other targets. It is used in scientific research for investigating the functions of the 5-HT2B receptor.
RS-102221 is a drug developed by Hoffmann–La Roche, which was one of the first compounds discovered that acts as a potent and selective antagonist at the serotonin 5-HT2C receptor, with around 100× selectivity over the closely related 5-HT2A and 5-HT2B receptors. It has anxiolytic effects in animal studies, increases the effectiveness of SSRI antidepressants, and shows a complex interaction with cocaine, increasing some effects but decreasing others, reflecting a role for the 5-HT2C receptor in regulation of the dopamine signalling system in the brain.
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.
Ro60-0175 is a drug developed by Hoffmann–La Roche, which has applications in scientific research. It acts as a potent and selective agonist for both the 5-HT2B and 5-HT2C serotonin receptor subtypes, with good selectivity over the closely related 5-HT2A subtype, and little or no affinity at other receptors.
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.
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.
Pruvanserin is a selective 5-HT2A receptor antagonist which was under development by Eli Lilly and Company for the treatment of insomnia. It was in phase II clinical trials in 2008 but appears to have been discontinued as it is no longer in the company's development pipeline. In addition to its sleep-improving properties, pruvanserin has also been shown to have antidepressant, anxiolytic, and working memory-enhancing effects in animal studies.
PRX-08066 is a drug discovered and developed by Predix Pharmaceuticals [Dale S. Dhanoa et al. Patent US 7,030,240 B2], which acts as a potent and selective antagonist at the serotonin 5-HT2B receptor, with a 5-HT2Bbinding affinity (Ki) of 3.4nM, and high selectivity over the closely related 5-HT2A and 5-HT2C receptors and other receptor targets. PRX-08066 and other selective 5-HT2B antagonists are being researched for the treatment of pulmonary arterial hypertension, following the discovery that the potent 5-HT2B agonist norfenfluramine produces pulmonary arterial hypertension and subsequent heart valve damage. In animal studies, PRX-08066 has been found to reduce several key indicators of pulmonary arterial hypertension and improved cardiac output, with similar efficacy to established drugs for this condition such as bosentan, sildenafil, beraprost and iloprost. It is also being researched for potential anti-cancer applications, due to its ability to inhibit fibroblast activation.
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.
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.
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.
SB-228357 is a drug which acts as an antagonist for the 5HT2B and 5HT2C receptors. It has antidepressant and anxiolytic effects in animal models, and inhibits 5-HT2B mediated proliferation of cardiac fibroblasts.
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