Alpha-adrenergic receptor alpha-1 and alpha-2 subtypes (α1A, α1B, α1D, α2A, α2B, α2C)

Alpha-adrenergic receptors are a class of G protein-coupled receptors that mediate the effects of catecholamines (primarily norepinephrine and epinephrine) in the sympathetic nervous system. There are two major types with multiple subtypes: Alpha-1 (α1A, α1B, α1D) receptors are primarily responsible for smooth muscle contraction and vasoconstriction, while Alpha-2 (α2A, α2B, α2C) receptors are involved in feedback inhibition of neurotransmitter release and can influence vascular tone and central nervous system functions. These receptors are prominent targets for drugs treating hypertension, urinary retention, psychiatric disease, and more, with distinct pharmacological profiles depending on subtype selectivity.

Other names

Alpha-adrenergic receptoradrenergic alpha receptoralpha-adrenoceptorα-adrenoceptorα1Aα1Bα1Dα2Aα2Bα2C

Agonists stimulate the receptors to induce downstream signaling (α1: Gq-phospholipase C/calcium mobilization; α2: Gi-inhibition of adenylyl cyclase, lowers cAMP). Antagonists block receptor activity, leading to vasodilation (α1 blockers) or increased neurotransmitter release (α2 blockers).