Alpha-2 Adrenergic Receptor (α2-AR)

The alpha-2 (α2) adrenergic receptor is a G protein-coupled receptor (GPCR) that primarily couples to the Gi class of heterotrimeric G-proteins. It plays a key role in modulating neurotransmitter release, vascular tone, and several central nervous system functions by responding to endogenous catecholamines such as norepinephrine and epinephrine. There are three main subtypes: α2A, α2B, and α2C. Activation inhibits adenylyl cyclase, reducing cAMP levels and resulting in decreased neurotransmitter release, sedation, analgesia, hypotension, and bradycardia. Agonists targeting these receptors have diverse clinical uses, including hypertension management, sedation, ADHD treatment, and muscle spasticity reduction.

Other names

Adrenergic receptor alpha-2Alpha2 adrenergic receptorα2 adrenergic receptorADRA2Alpha-2 Adrenoceptor

Agonists bind to the α2-AR, activating Gi/o proteins. This inhibits adenylyl cyclase, reducing cAMP levels and leading to decreased neurotransmitter release, sedation, analgesia, and altered vascular tone.