ECTOENZYMES AND METABOLISM OF EXTRACELLULAR ATP

Extracellular ATP can produce various effects acting via P-2-purinocep tors. ATP is rapidly broken down by ecto-ATPase and other ecto-enzymes that limit its effect. Further, adenosine, a metabolite of ATP breakd own, can produce its own effect acting via P-1-purinoceptors, sometime s masking the effects of ATP. An inhibitor of ATP degradation would be a useful pharmacological tool to discriminate between effects of ATP and its metabolites, as well as to potentiate its actions. Diverse com pounds that have been claimed to be inhibitors of ATP-metabolising ect oenzymes are evaluated, but specific and selective Ca2+/Mg2+-dependent ecto-ATPase inhibitors still appear to be lacking. (C) 1994 Wiley-Lis s, Inc.