Raclopride is a

typical antipsychotic Typical antipsychotics (also known as major tranquilizers, and first generation antipsychotics) are a class of antipsychotic drugs first developed in the 1950s and used to treat psychosis (in particular, schizophrenia). Typical antipsychotics ma ...

. It acts as a selective antagonist on D₂

dopamine receptor Dopamine receptors are a class of G protein-coupled receptors that are prominent in the vertebrate central nervous system (CNS). Dopamine receptors activate different effectors through not only G-protein coupling, but also signaling through diffe ...

s. It has been used in trials studying

Parkinson Disease Parkinson may refer to: *Parkinson (surname) * ''Parkinson'' (TV series), British chat show, presented by Sir Michael Parkinson *Parkinson, Queensland, suburb of Brisbane, Australia *The Parkinsons (fl. early 20th century), American father-and-son ...

. Its selectivity to the cerebral D₂ receptors is characterized by its respective K_i-values, which are as follows: 1.8, 3.5, 2400 and 18000 nM for D₂, D₃, D₄ and D₁ receptors respectively. It can be

radiolabelled Isotopic labeling (or isotopic labelling) is a technique used to track the passage of an isotope (an atom with a detectable variation in neutron count) through a reaction, metabolic pathway, or cell. The reactant is 'labeled' by replacing specific ...

with

radioisotopes A radionuclide (radioactive nuclide, radioisotope or radioactive isotope) is a nuclide that has excess nuclear energy, making it unstable. This excess energy can be used in one of three ways: emitted from the nucleus as gamma radiation; transferr ...

, e.g. ³H or ¹¹C and used as a tracer for ''

in vitro ''In vitro'' (meaning in glass, or ''in the glass'') studies are performed with microorganisms, cells, or biological molecules outside their normal biological context. Colloquially called " test-tube experiments", these studies in biology ...

'' imaging ( autoradiography) as well as ''

in vivo Studies that are ''in vivo'' (Latin for "within the living"; often not italicized in English) are those in which the effects of various biological entities are tested on whole, living organisms or cells, usually animals, including humans, and ...

'' imaging positron emission tomography (PET). Images obtained by cerebral PET scanning (e.g. PET/CT or PET/MRI) allow the non-invasive assessment of the binding capacity of the cerebral D₂ dopamine

receptor Receptor may refer to: * Sensory receptor, in physiology, any structure which, on receiving environmental stimuli, produces an informative nerve impulse *Receptor (biochemistry), in biochemistry, a protein molecule that receives and responds to a ...

, which can be useful for the diagnosis of movement disorders. In particular, cerebral D₂ receptor binding as measured by carbon-11-raclopride (¹¹C-raclopride) has shown to reflect disease severity of

Huntington's disease Huntington's disease (HD), also known as Huntington's chorea, is a neurodegenerative disease that is mostly inherited. The earliest symptoms are often subtle problems with mood or mental abilities. A general lack of coordination and an uns ...

, a genetic disease characterized by selective degeneration of cerebral D₂ receptors. Other studies have investigated the relationship of D₂ receptor binding capacity and

personality disorders Personality disorders (PD) are a class of mental disorders characterized by enduring maladaptive patterns of behavior, cognition, and inner experience, exhibited across many contexts and deviating from those accepted by the individual's culture ...

. One study found decreased binding in the '' detachment''

personality trait In psychology, trait theory (also called dispositional theory) is an approach to the study of human personality. Trait theorists are primarily interested in the measurement of ''traits'', which can be defined as habitual patterns of behaviour, tho ...

. Radiolabelled raclopride is also commonly used to determine the efficacy and

neurotoxicity Neurotoxicity is a form of toxicity in which a biological, chemical, or physical agent produces an adverse effect on the structure or function of the central and/or peripheral nervous system. It occurs when exposure to a substance – specificall ...

of dopaminergic drugs.

References

Benzamides Chloroarenes D2 antagonists Phenol ethers Pyrrolidines Typical antipsychotics {{nervous-system-drug-stub