Alpha-1 and alpha-2B adrenergic receptors (α1/α2B-AR)

Alpha-1 and alpha-2B adrenergic receptors are members of the G protein-coupled receptor (GPCR) superfamily that respond to the endogenous catecholamines norepinephrine and epinephrine [1]. Alpha-1 adrenoceptors (including α1A, α1B, and α1D subtypes) are primarily coupled to Gq proteins, leading to the activation of phospholipase C and subsequent smooth muscle contraction, particularly in the peripheral vasculature [4]. The alpha-2B adrenoceptor is a Gi/o-coupled subtype that also mediates vasoconstriction and plays a significant role in the central nervous system, specifically within spinal cord pathways involved in antinociception [3, 4]. These receptors are critical therapeutic targets in the management of hypertension, nasal congestion, and pain [1, 3]. Drugs such as oxymetazoline act as agonists to induce vasoconstriction for decongestion, while antagonists like phentolamine or pipamperone are used to modulate vascular tone or psychiatric symptoms [1, 2]. Dysregulation of these receptors is linked to cardiovascular diseases and chronic pain states, making them vital for both systemic and localized pharmacological interventions [1, 4].

Other names

α1- and α2B-adrenoceptorsAlpha-1 and alpha-2B adrenoceptorsADRA1 and ADRA2B

Agonism at these receptors typically induces vasoconstriction and analgesia, while antagonism leads to vasodilation and is used in managing hypertension or as an adjunct in psychiatric treatment.