[Encoded by human ADRB1 Gene (GPCR1 Family), 477-aa 51-kDa conserved Beta-1-Adrenergic Receptor is an integral membrane protein receptor for catecholamine epinephrine and norepinephrine neurotransmitters that activates adenylate cyclase through G protein action. ADRB1 phosphorylation by beta-adrenergic receptor kinase mediates receptor desensitization. Agonist and antagonist drugs selective for beta-1 receptors have important applications in clinical medicine. (NCI) ( NCI )]