The dopamine receptor D4 is a dopamine D2-like G protein-coupled receptor encoded by the DRD4 gene on chromosome 11 at 11p15.5.
Rotigotine is a dopamine agonist of the non-ergoline class of medications indicated for the treatment of Parkinson's disease (PD) and restless legs syndrome (RLS). It is formulated as a once-daily transdermal patch which provides a slow and constant supply of the drug over the course of 24 hours.
Dihydroergocryptine is a dopamine agonist of the ergoline chemical class that is used as an antiparkinson agent. Dihydroergocryptine has been shown to be particularly effective as monotherapy in the early stages of Parkinson's disease. Initial monotherapy with a dopamine agonist is associated with reduced risk for motor complications in Parkinson patients relative to levodopa. DHEC, like other dopamine agonists, aims to mimic the endogenous neurotransmitter and exert an antiparkinsonian effect. Recent evidence also supports that dopamine receptor agonists, instead of L-DOPA may slow or prevent the progression of Parkinson's disease.
The Gs alpha subunit is a heterotrimeric G protein subunit that activates the cAMP-dependent pathway by activating adenylyl cyclase. It is one of the three main families of G proteins: Gαi/Gαo, Gαq, and Gαs. A mnemonic for remembering this subunit is to look at the first letter.
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, is a protein that in humans is encoded by the DRD1 gene.
Dopamine receptor D5, also known as D1BR, is a protein that in humans is encoded by the DRD5 gene. It belongs to the D1-like receptor family along with the D1 receptor subtype.
Dopamine receptor D3 is a protein that in humans is encoded by the DRD3 gene.
Trace amine associated receptor 6, also known as TAAR6, is a protein which in humans is encoded by the TAAR6 gene.
Trace amine-associated receptor 1 (TAAR1) is a trace amine-associated receptor (TAAR) protein that in humans is encoded by the TAAR1 gene. TAAR1 is an intracellular amine-activated Gs-coupled and Gq-coupled G protein-coupled receptor (GPCR) that is primarily expressed in several peripheral organs and cells, astrocytes, and in the intracellular milieu within the presynaptic plasma membrane of monoamine neurons in the central nervous system (CNS). TAAR1 was discovered in 2001 by two independent groups of investigators, Borowski et al. and Bunzow et al. TAAR1 is one of six functional human trace amine-associated receptors, which are so named for their ability to bind endogenous amines that occur in tissues at trace concentrations. TAAR1 plays a significant role in regulating neurotransmission in dopamine, norepinephrine, and serotonin neurons in the CNS; it also affects immune system and neuroimmune system function through different mechanisms.
DnaJ homolog subfamily C member 14 is a protein that in humans is encoded by the DNAJC14 gene.
The D1-like receptors are a subfamily of dopamine receptors that bind the endogenous neurotransmitter dopamine. The D1-like subfamily consists of two G protein–coupled receptors that are coupled to Gs and mediate excitatory neurotransmission, of which include D1 and D5. For more information, please see the respective main articles of the individual subtypes:
SKF-83,959 is a synthetic benzazepine derivative used in scientific research which acts as an agonist at the D1-D2 dopamine receptor. It behaves as a full agonist at the D1 protomer and a high-affinity partial agonist at the D2 protomer. It was further shown to act as an allosteric modulator of the sigma-1 receptor. SKF-83,959 is a racemate that consists of the R-(+)- and S-(−)-enantiomers MCL 202 and MCL 201, respectively. SKF-83,959 inhibits sodium channels as well as delayed rectifier potassium channels.
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.
SKF-81,297 is a synthetic drug of the benzazepine chemical class that acts as a selective dopamine D1/D5 receptor full agonist, and produces a characteristic stimulant-like pattern of anorexia, hyperactivity and self-administration in animals. This profile is shared with several related drugs such as 6-Br-APB and SKF-82,958, but not with certain other D1 full agonists such as A-77,636, reflecting functional selectivity of D1 activation. Newer findings reveal that SKF-81,297 additionally acts as a partial agonist at D1-D2 receptor heteromers.
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.
Cariprazine, sold under the brand names Vraylar in the United States and Reagila in Europe, is an atypical antipsychotic which is used in the treatment of schizophrenia and bipolar mania. It acts primarily as a D3 receptor and D2 receptor partial agonist, with high selectivity for the D3 receptor. Positive Phase III study results were published for schizophrenia and mania in early 2012, and for bipolar disorder I depression from a Phase II trial in 2015. It is also potentially useful as an add-on therapy in major depressive disorder.
L-741,626 is a drug which acts as a potent and selective antagonist for the dopamine receptor D2. It has good selectivity over the related D3 and D4 subtypes and other receptors. L-741,626 is used for laboratory research into brain function and has proved particularly useful for distinguishing D2 mediated responses from those produced by the closely related D3 subtype, and for studying the roles of these subtypes in the action of cocaine and amphetamines in the brain.
