Pharmacology and molecular biology of adrenergic receptors.

The recent cloning of multiple adrenergic receptors has moved our understanding of these receptors from a conceptual one (Alquist, 1948) to one based on well-defined unique cellular proteins. The biochemical and pharmacological properties of these receptors can now be studied in detail by expression of a single subtype in cells normally devoid of adrenergic receptors. By site-directed mutagenesis, the relationship between the structures of these receptors and their function is now being elucidated for each adrenergic receptor subtype. These functions include the binding of catecholamines and other ligands, G protein coupling and functional regulation.