β-Adrenoceptor (β-AR)

β-adrenoceptors, also known as beta-adrenergic receptors or β-ARs, are a class of G protein-coupled receptors (GPCRs) that respond to catecholamines such as norepinephrine and epinephrine. They play critical roles in regulating cardiovascular, pulmonary, metabolic, and central nervous system functions. There are three main subtypes: β1, β2, and β3, each with distinct tissue distribution and physiological effects. Activation of β-adrenoceptors results in increased heart rate and force of contraction, relaxation of vascular/bronchial/urogenital smooth muscle, and stimulation of renin secretion. Agonists or antagonists targeting these receptors are widely used therapeutically for hypertension, arrhythmias, asthma/COPD, and obesity/bladder disorders. Upon ligand binding, the receptor activates Gs proteins, stimulating adenylyl cyclase and increasing cAMP levels.

Other names

Beta-adrenergic receptorBeta-adrenoceptorβ-adrenergic receptor

Activation via Gs → Adenylyl cyclase → ↑cAMP. Receptor shifts from an inactive to an active state, activating associated Gs proteins. Activated Gα stimulates adenylyl cyclase increasing cAMP production. cAMP acts as a second messenger activating downstream effectors such as PKA.