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.
Pindolol, sold under the brand name Visken among others, is a nonselective beta blocker which is used in the treatment of hypertension. It is also an antagonist of the serotonin 5-HT1A receptor, preferentially blocking inhibitory 5-HT1A autoreceptors, and has been researched as an add-on therapy to selective serotonin reuptake inhibitors (SSRIs) in the treatment of depression.
SKF-82,958 is a synthetic compound of the benzazepine class that acts as a D1/D5 receptor full agonist. SKF-82,958 and similar D1-like-selective full agonists like SKF-81,297 and 6-Br-APB produce characteristic anorectic effects, hyperactivity and self-administration in animals, with a similar but not identical profile to that of dopaminergic stimulants such as amphetamine. SKF-82,958 was also subsequently found to act as an agonist of ERα with negligible activity at ERβ, making it a subtype-selective estrogen.
A dopamine agonist(DA) is a compound that activates dopamine receptors. There are two families of dopamine receptors, D2-like and D1-like, and they are all G protein-coupled receptors. D1- and D5-receptors belong to the D1-like family and the D2-like family includes D2, D3 and D4 receptors. Dopamine agonists are primarily used in the treatment of Parkinson's disease, and to a lesser extent, in hyperprolactinemia and restless legs syndrome. They are also used off-label in the treatment of clinical depression. The use of dopamine agonists is associated with impulse control disorders and dopamine agonist withdrawal syndrome (DAWS).
Aporphine is an alkaloid with the chemical formula C17H17N. It is the core chemical substructure of the aporphine alkaloids, a subclass of quinoline alkaloids. It can exist in either of two enantiomeric forms, (R)-aporphine and (S)-aporphine.
Dopamine receptor D2, also known as D2R, is a protein that, in humans, is encoded by the DRD2 gene. After work from Paul Greengard's lab had suggested that dopamine receptors were the site of action of antipsychotic drugs, several groups, including those of Solomon Snyder and Philip Seeman used a radiolabeled antipsychotic drug to identify what is now known as the dopamine D2 receptor. The dopamine D2 receptor is the main receptor for most antipsychotic drugs. The structure of DRD2 in complex with the atypical antipsychotic risperidone has been determined.
Dopamine receptor D1, also known as DRD1. It is one of the two types of D1-like receptor family - receptors D1 and D5. It is a protein that in humans is encoded by the DRD1 gene.
The serotonin 1A receptor is a subtype of serotonin receptors, or 5-HT receptors, that binds serotonin, also known as 5-HT, a neurotransmitter. 5-HT1A is expressed in the brain, spleen, and neonatal kidney. It is a G protein-coupled receptor (GPCR), coupled to the Gi protein, and its activation in the brain mediates hyperpolarisation and reduction of firing rate of the postsynaptic neuron. In humans, the serotonin 1A receptor is encoded by the HTR1A gene.
Dopamine receptor D3 is a protein that in humans is encoded by the DRD3 gene.
Chloroethylnorapomorphine is a chemical once thought to be an irreversible dopamine D2 receptor antagonist; however, it was later proved to be reversible.
UH-232 ((+)-UH232) is a drug which acts as a subtype selective mixed agonist-antagonist for dopamine receptors, acting as a weak partial agonist at the D3 subtype, and an antagonist at D2Sh autoreceptors on dopaminergic nerve terminals. This causes dopamine release in the brain and has a stimulant effect, as well as blocking the behavioural effects of cocaine. It may also serve as a 5-HT2A receptor agonist, based on animal studies. It was investigated in clinical trials for the treatment of schizophrenia, but unexpectedly caused symptoms to become worse.
S-15535 is a phenylpiperazine drug which is a potent and highly selective 5-HT1A receptor ligand that acts as an agonist and antagonist at the presynaptic and postsynaptic 5-HT1A receptors, respectively. It has anxiolytic properties.
6-Br-APB is a synthetic compound that acts as a selective D1 agonist, with the (R)-enantiomer being a potent full agonist, while the (S) enantiomer retains its D1 selectivity but is a weak partial agonist. (R)-6-Br-APB and similar D1-selective full agonists like SKF-81,297 and SKF-82,958 produce characteristic anorectic effects, stereotyped behaviour and self-administration in animals, with a similar but not identical profile to that of dopaminergic stimulants such as amphetamine.
A-77636 is a synthetic drug which acts as a selective D1 receptor full agonist. It has nootropic, anorectic, rewarding and antiparkinsonian effects in animal studies, but its high potency and long duration of action causes D1 receptor downregulation and tachyphylaxis, and unlike other D1 full agonists such as SKF-82,958, it does not produce place preference in animals. A-77636 partially substituted for cocaine in animal studies, and has been suggested for use as a possible substitute drug in treating addiction, but it is better known for its use in studying the role of D1 receptors in the brain.
7-OH-DPAT is a synthetic compound that acts as a dopamine receptor agonist with reasonable selectivity for the D3 receptor subtype, and low affinity for serotonin receptors, unlike its structural isomer 8-OH-DPAT. 7-OH-DPAT is self-administered in several animal models, and is used to study addiction to cocaine.
2-OH-NPA is a drug used in scientific research which acts as a potent and selective agonist for the dopamine D2 receptor.
Eptapirone (F-11,440) is a very potent and highly selective 5-HT1A receptor full agonist of the azapirone family. Its affinity for the 5-HT1A receptor was reported to be 4.8 nM (Ki), and its intrinsic activity approximately equal to that of serotonin.
Roxindole (EMD-49,980) is a dopaminergic and serotonergic drug which was originally developed by Merck KGaA for the treatment of schizophrenia. In clinical trials its antipsychotic efficacy was only modest but it was unexpectedly found to produce potent and rapid antidepressant and anxiolytic effects. As a result, roxindole was further researched for the treatment of depression instead. It has also been investigated as a therapy for Parkinson's disease and prolactinoma.
CY-208,243 is a drug which acts as a dopamine agonist selective for the D1 subtype. Unlike most D1-selective agonists, it shows efficacy in animal models of Parkinson's disease.
OSU-6162 (PNU-96391) is a compound which acts as a partial agonist at both dopamine D2 receptors and 5-HT2A receptors. It acts as a dopamine stabilizer in a similar manner to the closely related drug pridopidine, and has antipsychotic, anti-addictive and anti-Parkinsonian effects in animal studies. Both enantiomers show similar activity but with different ratios of effects, with the (S) enantiomer (–)-OSU-6162 that is more commonly used in research, having higher binding affinity to D2 but is a weaker partial agonist at 5-HT2A, while the (R) enantiomer (+)-OSU-6162 has higher efficacy at 5-HT2A but lower D2 affinity.
