What is the Origin of Adrenergic Receptors?

The term is rooted in the physiological action of adrenaline, which is also known as epinephrine, and the recognition that specific cellular components respond to this neurohormone. The systematic classification of alpha and beta receptors was pioneered by pharmacologists who observed differential responses to various agonists and antagonists. This foundational work was crucial for the development of targeted cardiovascular and respiratory medications.

What is the Mechanism of Adrenergic Receptors?

Upon binding of an adrenergic ligand, the receptor undergoes a conformational change that activates an intracellular G protein. This G protein then initiates a second messenger cascade, most commonly involving adenylyl cyclase or phospholipase C, which modulates intracellular enzyme activity. The specific cellular response is dictated by the receptor subtype; for example, beta-1 activation increases heart contractility, while alpha-1 activation typically causes smooth muscle contraction and vasoconstriction.

Adrenergic Receptors

Meaning

Adrenergic receptors, also known as adrenoceptors, are a class of G protein-coupled receptors that serve as the primary targets for the endogenous catecholamines, epinephrine and norepinephrine. These receptors are widely distributed throughout the body and mediate the diverse physiological effects of the sympathetic nervous system, often termed the “fight-or-flight” response. Clinically, they are subdivided into alpha (α) and beta (β) receptor families, each with distinct subtypes and pharmacological profiles.