Design of new beta1-selective adrenoceptor ligands as potential radioligands for in vivo imaging.

In general, the failing human heart is characterized by a selective reduction in beta(1)-adrenoceptors (beta(1)-ARs) without change in beta(2)-AR density. Medical imaging techniques, either single photon emission computed tomography (SPECT) or positron emission tomography (PET) with appropriate radioligands, offer the possibility of assessing beta-adrenoceptor density non-invasively in humans. To date, neither a SPECT nor a PET radioligand is available for the selective imaging of cardiac beta(1)-ARs.