G-Protein Coupled Receptor adenosine receptor Four adenosine receptors have been cloned and characterized from several mammalian species. The receptors are named adenosine A1, A2A, A2B, and A3. The A2A and A2B receptors preferably interact with members of the Gs family of G proteins and the A1 and A3 receptors with Gi/o proteins. GO:0001609 IMR:0002675 molecule_role