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.
The dopamine receptor D4 is a dopamine D2-like G protein-coupled receptor encoded by the DRD4 gene on chromosome 11 at 11p15.5.
SB-277,011A is a drug which acts as a potent and selective dopamine D3 receptor antagonist, which is around 80-100x selective for D3 over D2, and lacks any partial agonist activity.
The serotonin 1A receptor is a subtype of serotonin receptor, or 5-HT receptor, 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.
AM-411 is an analgesic drug that is a cannabinoid agonist. It is a derivative of Δ8-THC substituted with an adamantyl group at the 3-position, demonstrating that the binding pocket for the alkyl chain at this position can accommodate significant bulk.
Pozanicline is a drug developed by Abbott, that has nootropic and neuroprotective effects. Animal studies suggested it useful for the treatment of ADHD and subsequent human trials have shown ABT-089 to be effective for this application. It binds with high affinity subtype-selective to the α4β2 nicotinic acetylcholine receptors and has partial agonism to the α6β2 subtype, but not the α7 and α3β4 subtypes familiar to nicotine. It has particularly low tendency to cause side effects compared to other drugs in the class, making it an exciting candidate for clinical development.
ELB-139 (LS-191,811) is an anxiolytic drug with a novel chemical structure, which is used in scientific research. It has similar effects to benzodiazepine drugs, but is structurally distinct and so is classed as a nonbenzodiazepine anxiolytic.
SB-399885 is a drug which is used in scientific research. It acts as a potent, selective and orally active 5-HT6 receptor antagonist, with a Ki of 9.0nM. SB-399885 and other 5-HT6 antagonists show nootropic effects in animal studies, as well as antidepressant and anxiolytic effects which are comparable to and synergistic with drugs such as imipramine and diazepam, and have been proposed as potential novel treatments for cognitive disorders such as schizophrenia and Alzheimer's disease.
SB-357134 is a drug which is used in scientific research. It acts as a potent, selective and orally active 5-HT6 receptor antagonist. SB-357134 and other 5-HT6 antagonists show nootropic effects in animal studies, and have been proposed as potential novel treatments for cognitive disorders such as schizophrenia and Alzheimer's disease.
CP-94253 is a drug which acts as a potent and selective serotonin 5-HT1B receptor agonist, with approximately 25x and 40x selectivity over the closely related 5-HT1D and 5-HT1A receptors. It has a range of behavioral effects, based on animal testing. The effects include the following: promoting wakefulness by increasing dopamine release in the brain; reducing food intake and promoting satiety; enhancing the reinforcing effects of cocaine; and possible antidepressant effects.A recent study found that "Regardless of sex, CP94253 decreased cocaine intake after abstinence and during resumption of SA [self-administration] and decreased cue reactivity" suggesting that agonism of the inhibitory 5-HT2B receptors may diminish the cognitive reward of cocaine usage and increased use of the drug without a period of abstinence may be a product of test subjects trying to achieve a previously rewarding experience through larger dosages of cocaine.
GR-127935 is a drug which acts as a selective antagonist at the serotonin receptors 5-HT1B and 5-HT1D. It has little effect when given by itself but blocks the antiaggressive effect of 5-HT1B agonists, and alters release of serotonin in the brain, as well as reducing drug-seeking behaviour in cocaine addicted rats.
A serenic, or antiaggressive agent, is a type of drug which reduces the capacity for irritability and aggression.
A-68930 is a synthetic compound that acts as a selective dopamine receptor D1 agonist. It is orally active and has antidepressant and anorectic effects in animals, producing wakefulness and tachycardia, but without stimulant effects, instead producing sedation. The difference in effects between A-68930 and other D1 agonists such as SKF-82958 may be due to their differing effects on the related D5 receptor.
8-OH-PBZI is a drug used in scientific research which acts as a potent and selective agonist for the dopamine D3 receptor.
Osemozotan (MKC-242) is a selective 5-HT1A receptor agonist with some functional selectivity, acting as a full agonist at presynaptic and a partial agonist at postsynaptic 5-HT1A receptors. 5-HT1A receptor stimulation influences the release of various neurotransmitters including serotonin, dopamine, norepinephrine, and acetylcholine. 5-HT1A receptors are inhibitory G protein-coupled receptor. Osemozotan has antidepressant, anxiolytic, antiobsessional, serenic, and analgesic effects in animal studies, and is used to investigate the role of 5-HT1A receptors in modulating the release of dopamine and serotonin in the brain, and their involvement in addiction to abused stimulants such as cocaine and methamphetamine.
SKF-77,434 is a drug which acts as a selective dopamine D1 receptor partial agonist, and has stimulant and anorectic effects. Unlike other D1 agonists with higher efficacy such as SKF-81,297 and 6-Br-APB, SKF-77,434 does not maintain self-administration in animal studies, and so has been researched as a potential treatment for cocaine addiction.
PNU-99,194(A) (or U-99,194(A)) is a drug which acts as a moderately selective D3 receptor antagonist with ~15-30-fold preference for D3 over the D2 subtype. Though it has substantially greater preference for D3 over D2, the latter receptor does still play some role in its effects, as evidenced by the fact that PNU-99,194 weakly stimulates both prolactin secretion and striatal dopamine synthesis, actions it does not share with the more selective (100-fold) D3 receptor antagonists S-14,297 and GR-103,691.
BP-897 is a drug used in scientific research which acts as a potent selective dopamine D3 receptor partial agonist with an in vitro intrinsic activity of ~0.6 and ~70x greater affinity for D3 over D2 receptors and is suspected to have partial agonist or antagonist activity in vivo. It has mainly been used in the study of treatments for cocaine addiction. A study comparing BP-897 with the potent, antagonistic, and highly D3 selective SB-277,011-A found, "SB 277011-A (1–10 mg/kg) was able to block cue-induced reinstatement of nicotine-seeking, indicating that DRD3 selective antagonism may be an effective approach to prevent relapse for nicotine. In contrast, BP 897 did not block the cue-induced reinstatement of nicotine-seeking or nicotine-taking under the FR5 schedule."
A serotonin modulator and stimulator (SMS), sometimes referred to more simply as a serotonin modulator, is a type of drug with a multimodal action specific to the serotonin neurotransmitter system. To be precise, SMSs simultaneously modulate one or more serotonin receptors and inhibit the reuptake of serotonin. The term was created to describe the mechanism of action of the serotonergic antidepressant vortioxetine, which acts as a serotonin reuptake inhibitor (SRI), agonist of the 5-HT1A receptor, and antagonist of the 5-HT3 and 5-HT7 receptors. However, it can also technically be applied to vilazodone, which is an antidepressant as well and acts as an SRI and 5-HT1A receptor partial agonist.
