The putative β4-adrenergic receptor is a novel state of the β1-adrenergic receptor

Abstract

The atypical β3-adrenergic receptor (AR) agonist CGP-12177 has been used to define a novel atypical β-AR subtype, the putative β4-AR. Recent evaluation of recombinant β-AR subtypes and β-AR-deficient mice, however, has established the identity of the pharmacological β4-AR as a novel state of the β1-AR protein. The ability of aryloxypropanolamine ligands like CGP-12177 to independently interact with agonist and antagonist states of the β1-AR has important implications regarding receptor classification and the potential development of tissue-specific β-AR agonists.