Alpha-Adrenoreceptor

The α-adrenoreceptors (alpha-adrenergic receptors) are a class of G protein-coupled receptors (GPCRs) that respond to catecholamines, primarily norepinephrine and epinephrine. They play key roles in the sympathetic nervous system, mediating physiological responses such as vasoconstriction, neurotransmitter release modulation, and smooth muscle contraction. There are two main types: α1 and α2 adrenoreceptors, each with subtypes (α1A, α1B, α1D and α2A, α2B, α2C respectively). α₁-receptors couple to the Gq protein, increasing intracellular Ca²⁺ leading to smooth muscle contraction, while α₂-receptors couple to the Gi protein, decreasing cAMP levels and inhibiting neurotransmitter release. Blockade or stimulation of these receptors underlies many therapeutic strategies targeting cardiovascular diseases, psychiatric disorders, pain management, and urological conditions.

Other names

α-AdrenoreceptorAlpha-Adrenergic Receptorα-Adrenergic Receptor

Alpha₁: Gq → ↑Ca²⁺ → Contraction Alpha₂: Gi → ↓cAMP → Inhibition