New potent, short-linker BODIPY-630/650™ labelled fluorescent adenosine receptor agonists

Abstract

New, short-linker BODIPY 630/650™ fluorescent conjugates of the adenosine receptor ligand N-ethylcarboxamido-adenosine (NECA) have been synthesised and pharmacologically evaluated. These novel conjugates confirm that short linkers between the N⁶-amino group of NECA and the fluorophore are preferred with the best ligand (15b, aminopropyl linker) displaying the greatest potency (Log IC₅₀ (G_i) = −9.31) at the human adenosine A1-receptor. Imaging studies with this compound confirmed it can be employed to selectively label the human adenosine A1-receptor in single living cells, with receptor-associated binding prevented by preincubation with the nonfluorescent antagonist DPCPX.