Alpha-2A, Alpha-2B, Alpha-2C adrenergic receptors (ADRA2A, ADRA2B, ADRA2C)

The alpha-2 adrenergic receptors (Alpha-2A, Alpha-2B, Alpha-2C) are a subfamily of G protein-coupled receptors that mediate the actions of norepinephrine and epinephrine in the central and peripheral nervous systems. They play critical roles in regulating sympathetic nervous system outflow, neurotransmitter release, vascular tone, blood pressure, and heart rate. Each subtype has both overlapping and distinct physiological functions: - Alpha-2A is the major presynaptic inhibitory receptor in the CNS and is targeted by antihypertensive and sedative drugs like clonidine and dexmedetomidine. - Alpha-2B is prominent in peripheral blood vessels and is implicated in vascular responses and developmental processes. - Alpha-2C regulates neurotransmission at low neural activity levels and influences startle reflex and stress responses. Alterations in the expression or function of these receptors are associated with cardiovascular, psychiatric, and oncologic disease phenotypes, and genetic variants contribute to interindividual variations in drug efficacy and disease susceptibility. Drugs targeting these receptors are used in anesthesia, hypertension, ADHD, and psychiatric disorders, while their role as biomarkers and therapeutic targets is expanding in oncology and personalized medicine.

Other names

α2A adrenergic receptoralpha-2A adrenoceptorα2B adrenergic receptoralpha-2B adrenoceptorα2C adrenergic receptoralpha-2C adrenoceptorAlpha2A-ARAlpha2B-ARAlpha2C-AR

Agonists: Activate (agonize) the alpha-2 adrenergic receptor, resulting in inhibition of norepinephrine release, reduced sympathetic outflow, analgesia, sedation, and lowering of blood pressure. Antagonists: Block the alpha-2 adrenergic receptor, enhancing norepinephrine release, increasing sympathetic tone, and potentially increasing blood pressure.