ECTOENZYMES AND METABOLISM OF EXTRACELLULAR ATP

Extracellular ATP can produce various effects acting via P-2-purinoceptors. ATP is rapidly broken down by ecto-ATPase and other ecto-enzymes that limit its effect. Further, adenosine, a metabolite of ATP breakdown, can produce its own effect acting via P-1-purinoceptors, sometimes 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 compounds that have been claimed to be inhibitors of ATP-metabolising ectoenzymes are evaluated, but specific and selective Ca2+/Mg2+-dependent ecto-ATPase inhibitors still appear to be lacking. (C) 1994 Wiley-Liss, Inc.