Alpha-1A adrenergic receptor; Alpha-1D adrenergic receptor (α1A-AR; α1D-AR)

The alpha-1A and alpha-1D adrenergic receptors are subtypes of the alpha-1 adrenergic receptor family, which are G protein-coupled receptors primarily responsive to the endogenous catecholamines noradrenaline and adrenaline[1][2][3][4]. These receptors play essential roles in regulating vascular smooth muscle contraction, controlling blood pressure, modulating lower urinary tract function, and influencing cognition[2][3][4]. There are three α1-adrenoceptor subtypes: α1A, α1B, and α1D, each with overlapping but distinct tissue distributions and functional roles. The α1A subtype is particularly important in the prostate and lower urinary tract, while both α1A and α1D are expressed in vascular tissues and involved in blood pressure regulation[1][3]. They are major targets for antihypertensive and urological therapies, especially selective antagonists for the treatment of hypertension and benign prostatic hyperplasia. Selective drugs targeting these subtypes are being developed to maximize clinical benefits and reduce unwanted side effects driven by less selective inhibition of related receptor subtypes[2][3][5].

Other names

ADRA1AADRA1Dα1A-adrenoceptorα1D-adrenoceptoralpha-1A adrenoceptoralpha-1D adrenoceptor

Agonists stimulate Gq protein signaling, activating phospholipase C (PLC), leading to inositol trisphosphate (IP3) and diacylglycerol (DAG) formation, triggering intracellular calcium release and kinase activation. Antagonists block these signaling pathways, reducing smooth muscle contraction and lowering vascular/urinary tract tone.