Alpha-2 Adrenoreceptor (α2 adrenergic receptor)

The alpha-2 adrenoreceptor (α2 adrenergic receptor) is a G protein-coupled receptor (GPCR) that primarily couples to the Gi class of heterotrimeric G-proteins. It mediates physiological responses to catecholamines, such as norepinephrine and epinephrine, in both the central and peripheral nervous systems. Activation leads to inhibition of adenylyl cyclase, decreased cAMP, and reduced neurotransmitter release. Subtypes include α2A, α2B, and α2C, with distinct localization and functions. Agonists like clonidine and dexmedetomidine are used for various therapeutic purposes, including hypertension management, sedation, and analgesia.

Other names

Alpha-2 Adrenergic Receptorα2-ARADRA2

Activation of alpha-2 adrenoreceptors inhibits adenylyl cyclase via Gi proteins, reducing cyclic AMP levels and leading to hyperpolarization. This decreases calcium influx at nerve terminals and suppresses neurotransmitter release, particularly norepinephrine.