The alpha-2A adrenergic receptor (α_2A adrenoceptor), also known as ADRA2A, is an α₂ adrenergic receptor, and also denotes the

human gene This article is an index of lists of human genes. By chromosome Below is a list of articles on human chromosomes, each of which contains an incomplete list of genes located on that chromosome. * Chromosome 1 (human) * Chromosome 2 (human) * ...

encoding it.

Receptor

α₂ adrenergic receptors include 3 highly homologous subtypes: α_2A, α_2B, and α_2C. These receptors have a critical role in regulating

neurotransmitter A neurotransmitter is a signaling molecule secreted by a neuron to affect another cell across a synapse. The cell receiving the signal, any main body part or target cell, may be another neuron, but could also be a gland or muscle cell. Neu ...

release from

sympathetic nerves The sympathetic nervous system (SNS) is one of the three divisions of the autonomic nervous system, the others being the parasympathetic nervous system and the enteric nervous system. The enteric nervous system is sometimes considered part of the ...

and from adrenergic neurons in the

central nervous system The central nervous system (CNS) is the part of the nervous system consisting primarily of the brain and spinal cord. The CNS is so named because the brain integrates the received information and coordinates and influences the activity of all p ...

. Studies in mice revealed that both the α_2A and α_2C subtypes were required for normal

presynaptic In the nervous system, a synapse is a structure that permits a neuron (or nerve cell) to pass an electrical or chemical signal to another neuron or to the target effector cell. Synapses are essential to the transmission of nervous impulses from ...

control of transmitter release from sympathetic nerves in the

heart The heart is a muscular Organ (biology), organ in most animals. This organ pumps blood through the blood vessels of the circulatory system. The pumped blood carries oxygen and nutrients to the body, while carrying metabolic waste such as ca ...

and from central noradrenergic neurons; the α_2A subtype inhibited transmitter release at high stimulation frequencies, whereas the α_2C subtype modulated neurotransmission at lower levels of nerve activity

Gene

This gene encodes α_2A subtype and it contains no

introns An intron is any nucleotide sequence within a gene that is not expressed or operative in the final RNA product. The word ''intron'' is derived from the term ''intragenic region'', i.e. a region inside a gene."The notion of the cistron .e., gene ...

in either its coding or

untranslated sequence A non-coding RNA (ncRNA) is a functional RNA molecule that is not translated into a protein. The DNA sequence from which a functional non-coding RNA is transcribed is often called an RNA gene. Abundant and functionally important types of non- ...

Role in central nervous system

Although the pre-synaptic functions of α_2A receptors are often a major focus, the majority of α₂ receptors in the brain are actually localized post-synaptically to noradrenergic terminals, and therefore aid in the function of

norepinephrine Norepinephrine (NE), also called noradrenaline (NA) or noradrenalin, is an organic chemical in the catecholamine family that functions in the brain and body as both a hormone and neurotransmitter. The name "noradrenaline" (from Latin '' ad ...

. Many post-synaptic α_2A receptors have important effects on brain function; for example, α_2A receptors are localized on prefrontal cortical neurons where they regulate higher cognitive function .

Ligands

Agonists

* 4-NEMD *

Brimonidine Brimonidine is a medication used to treat open-angle glaucoma, ocular hypertension, and rosacea. In rosacea it improves the redness. It is used as eye drops or applied to the skin. Common side effects when used in the eyes include itchiness, ...

Clonidine Clonidine, sold under the brand name Catapres among others, is an α2-adrenergic agonist medication used to treat high blood pressure, ADHD, drug withdrawal ( alcohol, opioids, or nicotine), menopausal flushing, diarrhea, spasticity, and c ...

* Dexmedetomidine * Guanfacine * Lofexidine *

Myrcene Myrcene, or β-myrcene, is a monoterpene. A colorless oil, it occurs widely in essential oils. It is produced mainly semi-synthetically from ''Myrcia'', from which it gets its name. It is an intermediate in the production of several fragrances. � ...

* Medetomidine * PS75 *

Tizanidine Tizanidine, sold under the brand name Zanaflex among others, is a medication that is used to treat muscle spasticity due to spinal cord injury or multiple sclerosis as well as spastic cerebral palsy. Effectiveness appears similar to baclofen ...

Xylazine Xylazine is a pharmaceutical drug used for sedation, anesthesia, muscle relaxation, and analgesia in animals such as horses, cattle, and other non-human mammals. Veterinarians also use xylazine as an emetic, especially in cats. It is an anal ...

Antagonists

* Idazoxan * 1-PP (active metabolite of

buspirone Buspirone, sold under the brand name Buspar, among others, is a medication primarily used to treat anxiety disorders, particularly generalized anxiety disorder. Benefits support its short-term use. It is taken by mouth, and it may take up to fo ...

and

gepirone Gepirone is an antidepressant and anxiolytic drug of the azapirone group that was synthesized by Bristol-Myers Squibb in 1986 and has been under development for the treatment of depression but has yet to be marketed. It has been under developmen ...

) * Asenapine * BRL-44408 *

Clozapine Clozapine is a psychiatric medication and is the first atypical antipsychotic (also called second-generation antipsychotic). It is primarily used to treat people with schizophrenia and schizoaffective disorders who have had an inadequate respo ...

* Lurasidone *

Mianserin Mianserin, sold under the brand name Tolvon among others, is an atypical antidepressant that is used primarily in the treatment of depression in Europe and elsewhere in the world. It is a tetracyclic antidepressant (TeCA). Mianserin is closel ...

Mirtazapine Mirtazapine, sold under the brand name Remeron amongst others, is an atypical antidepressant, and as such is used primarily to treat depression. Its effects may take up to four weeks, but can also manifest as early as one to two weeks. It is o ...

Paliperidone Paliperidone, sold under the trade name Invega among others, is an atypical antipsychotic. It is mainly used to treat schizophrenia and schizoaffective disorder. It is marketed by Janssen Pharmaceuticals. An extended release formulation is a ...

Risperidone Risperidone, sold under the brand name Risperdal among others, is an atypical antipsychotic used to treat schizophrenia and bipolar disorder. It is taken either by mouth or by injection (subcutaneous or intramuscular). The injectable versions ...

Yohimbine Yohimbine (), also known as quebrachine, is an indole alkaloid derived from the bark of the African tree '' Pausinystalia johimbe''; also from the bark of the unrelated South American tree ''Aspidosperma quebracho-blanco''. Yohimbine is an α2 ...

References

External links

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