John W. Daly

Adenosine Receptors:Selective Agonists and Antagonists

Adenosine receptors are members of the superfamily of receptors having seven trans-membrane domains and coupled to guanyl nucleotide-binding protein (G proteins). The A1, A2a, A2d, and A3 adenosine receptors have been cloned from several species, including in each case rat, dog, mouse, and human. The A1 and A3 receptors couple via G proteins to adenylate cyclase (inhibition), phospholipase C (activation), and, in the case of A1receptors, to potassium channels (activation) and calcium channels (inhibition). The A2a and A2b receptors couple via G proteins to adenylate cyclase (activation). A putative A4 receptor has not been cloned and will not be included in the present overview.