Alpha-1A adrenergic receptor and Alpha-1B adrenergic receptor (α1A-AR and α1B-AR)

Alpha-1A and Alpha-1B adrenergic receptors are subtypes of the alpha-1 adrenergic receptor family, which are G protein-coupled receptors responsive primarily to the endogenous catecholamines norepinephrine and epinephrine. These receptors play a vital role in mediating smooth muscle contraction, regulating vascular tone and blood pressure, contributing to cognitive and cardiac function, and controlling cell proliferation. Alpha-1A is especially important in the lower urinary tract and cerebral functions, while alpha-1B is involved in vascular smooth muscle and growth regulation. Both are targeted therapeutically by alpha-1 antagonists to treat conditions such as hypertension and benign prostatic hyperplasia, with subtype-selective drugs (e.g., tamsulosin, silodosin) offering organ-specific effects with fewer systemic side effects. Their pharmacology and structure are well-studied, with recent advances including high-resolution cryo-EM structures informing rational drug design. *For optimal structured data, separate records should be created for "Alpha-1A adrenergic receptor" and "Alpha-1B adrenergic receptor."

Other names

ADRA1Aalpha-1A-adrenoreceptorADRA1Balpha-1B-adrenoreceptor

Antagonists: Block endogenous catecholamine (norepinephrine, epinephrine) binding, resulting in vasodilation (lowering blood pressure), smooth muscle relaxation (improving urine flow in BPH), CNS effects. Agonists: Mimic catecholamines, cause smooth muscle contraction, increase blood pressure, or have subtype-specific central/CV actions. Inverse agonists: Some antagonists can suppress basal receptor activity even below baseline.