Potent and highly selective agonist at A 1 adenosine receptors (K i values are 3.3, 9580, 37600 and 1150 nM for human recombinant A 1 , A 2A , A 2B and A 3 receptors respectively). Acts as a full agonist; inhibits forskolin-stimulated adenylyl cyclase activity in rat cortical membranes with an IC 50 value of 13.1 nM.