Adrenergic alpha-1 Receptor Agonists

Adrenergic α₁ receptors (α₁-adrenoceptors) are members of the adrenergic receptor group of G-protein-coupled receptors that also includes α_2A, α_2B, α_2C, β₁, β₂ and β₃. The adrenergic α₁ receptors are further divided into three subtypes: α_1A, α_1B and α_1D receptors. α₁-adrenoceptors are widely distributed in both the CNS and periphery where they play a major role in smooth muscle contraction. A fourth α₁ receptor subtype has been postulated and is designated as α_1L based on its low affinity for prazosin. It has been suggested that this subtype may represent a different conformational state of the α_1A subtype.