Adrenaline and noradrenaline bind to membrane receptors of the superfamily of G protein-coupled receptors (GPCR) in target cells, where they modulate physiological responses such as metabolism, vasoconstriction, vasodilation and proliferation. Alteration in their function is associated with conditions such as hypertension, benign prostatic hyperplasia and cardiac hypertrophy.  The adrenergic receptors can be broadly categorized according to the class of G proteins and effector systems activated following agonist activation. Signal transduction by adrenergic receptors is regulated by changes in the functional state of the receptor as well as the number of receptors on the surface of the cell. In response to adrenaline, receptors form signaling complexes, which enables adrenergic action to be specific, rapid and efficient. These signaling complexes or signalosomes are composed of kinases, phosphatases, and adapter and scaffold proteins, which together modulate the receptor function.

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