Ecto-ATPdiphosphohydrolase from normal and abnormal placenta

Kettlun, AM, Collados, L, García, L, Chayet, L, Mancilla, M, Acevedo, CG, Bravo, I, Aranda, E, Traverso-Cori, A., Valenzuela, MA.; Plesner, L, Kirley, TL, AF Knowles, AF.

Keywords: platelet aggregation, Adenylate Kinase, Immune Serum Extracellular Nucleotide, Placental Sample


Vasoactive properties of adenosine and ATP on placenta has been described.1 Adenosine has been associated with vasodilation and ATP has a dual effect (vasodilation and vasoconstriction) depending on the receptors to which it binds. ADP is a powerful platelet stimulant, whereas ATP and adenosine inhibits ADP-induced platelet aggregation2. Mechanims of inactivation of circulating nucleotides, which imply the sequential degration of nucleoside di- and triphosphates to adenosine, are important in the control of their vascular actions. The scavenging of extracellular nucleotides is only possible in the dephosphorylated form3. We propose that ATP-diphosphohydrolase or apyrase (E. C., characterized by its ATPase and ADPase activities, could be involved in the regulation of the extracellular nucleotide levels acting together with 5′-nueleotidase4. This enzyme has been found localized as an ectoenzyme in erythrocytes and platelets5,6, as well as in endothelial and smooth muscle cells7. Apyrase is different from the high affinity Ca2+-ATPase involved in the Ca2+ transport8 and its function has been associated to platelet aggregation inhibition. The placental tissue does not produce significant amounts of PGI2, a potent platelet antiaggregant and ADPase activity could be the most important part of the anti-platelet activity

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Editorial: Springer
Fecha de publicación: 1997
Página de inicio: 49
Página final: 55
Idioma: Ingles