Adrenergic receptor (AR) (AR)

Adrenergic receptors, also known as adrenoceptors, are a class of G-protein-coupled receptors that mediate the physiological responses to the catecholamines epinephrine and norepinephrine. They are broadly categorized into alpha and beta types, which are further divided into nine distinct subtypes that exhibit unique tissue distributions and signaling mechanisms [1][2]. These receptors play a critical role in the sympathetic nervous system, regulating the "fight-or-flight" response by influencing heart rate, blood pressure, and airway diameter. Alpha receptors primarily mediate vasoconstriction and smooth muscle contraction, while beta receptors are involved in increasing cardiac output and inducing bronchodilation [1][3]. Because of their widespread influence on vital organ systems, adrenergic receptors are major therapeutic targets for conditions such as hypertension, heart failure, asthma, and allergic reactions. Drugs targeting these receptors include both agonists, which activate the receptors to treat conditions like shock or asthma, and antagonists, which block them to manage cardiovascular diseases [2][4].

Other names

AdrenoceptorAdrenoreceptorCatecholamine receptorAlpha and beta adrenoceptors

Adrenergic receptors function as G-protein-coupled receptors that respond to endogenous catecholamines. Alpha-1 receptors couple to Gq proteins to increase intracellular calcium; Alpha-2 receptors couple to Gi proteins to inhibit adenylate cyclase and decrease cAMP; and Beta receptors (1, 2, and 3) couple to Gs proteins to stimulate adenylate cyclase and increase cAMP levels [1][2].