Adrenergic receptors (also called adrenoceptors) are the receptors for the catecholamines adrenaline and noradrenaline (called epinephrine and norepinephrine in the United States). Adrenaline and noradrenaline play important roles in the control of blood pressure, myocardial contractile rate and force, airway reactivity, and a variety of metabolic and central nervous system functions.

Adrenergic receptors are members of the G-protein coupled receptor (GPCR) superfamily of membrane proteins. They share a common structure of seven putative transmembrane domains, an extracellular N-terminus, and a cytoplasmic C- terminus.

Adrenoceptors are divided into three types: α₁, α₂ and β-adrenoceptors. Each type is further divided into at least three subtypes: α_1A, α_1B, α_1D, α_2A, α_2B, α_2C, β₁, β₂, β₃^1,2. Adrenoceptors are expressed in nearly all peripheral tissues and in the central nervous system^1,2.

The α_2C-adrenoceptor subtype was identified by binding studies in the opossum kidney and in cell lines from this organ (OK cells)^3,4.

Surprisingly, the α_2C-adrenoceptor subtype seems not to play a major role in cardiovascular regulation or the other classical effects of α₂-adrenergic receptors⁵. Some researchers have suggested that the α_2C-adrenoceptor subtype may play a role in modulating motor behaviour and perhaps in memory processes⁶.