Historically, the major emphasis on the study of purinergic systems has been predominantly in the areas of physiology and gross pharmacology. The last decade has seen an exponential in crease in the number of publications related to the role of both adenosine and A TP in mammalian tissue function, a level of interest that has evolved from a more molecular focus on the identity of adenosine and A TP receptor subtypes and the search for selective ligands and development of radioligand binding assays by Fred Bruns and colleagues (especially that for A receptors) that played z a highly...