Brain ischemia alters platelet ATP disphosphohydrolase and 5'-nucleotidase activities in naive and preconditioned rats

dc.creatorFrasseto, Silvana Soriano
dc.creatorSchetinger, Maria Rosa Chitolina
dc.creatorSchierholt, Rejane Cristina
dc.creatorWebber, Analupe
dc.creatorBonan, Carla Denise
dc.creatorWyse, Angela Terezinha de Souza
dc.creatorDias, Renato Dutra
dc.creatorNetto, Carlos Alexandre
dc.creatorSarkis, João José Freitas
dc.date2010-04-24T04:15:33Z
dc.date2000
dc.identifier0100-879X
dc.identifierhttp://hdl.handle.net/10183/21169
dc.identifier000297780
dc.descriptionThe effects of transient forebrain ischemia, reperfusion and ischemic preconditioning on rat blood platelet ATP diphosphohydrolase and 5'- nucleotidase activities were evaluated. Adult Wistar rats were submitted to 2 or 10 min of single ischemic episodes, or to 10 min of ischemia 1 day after a 2-min ischemic episode (ischemic preconditioning) by the four-vessel occlusion method. Rats submitted to single ischemic insults were reperfused for 60 min and for 1, 2, 5, 10 and 30 days after ischemia; preconditioned rats were reperfused for 60 min 1 and 2 days after the long ischemic episode. Brain ischemia (2 or 10 min) inhibited ATP and ADP hydrolysis by platelet ATP diphosphohydrolase. On the other hand, AMP hydrolysis by 5'-nucleotidase was increased after 2, but not 10, min of ischemia. Ischemic preconditioning followed by 10 min of ischemia caused activation of both enzymes. Variable periods of reperfusion distinctly affected each experimental group. Enzyme activities returned to control levels in the 2-min group. However, the decrease in ATP diphosphohydrolase activity was maintained up to 30 days of reperfusion after 10-min ischemia. 5'-Nucleotidase activity was decreased 60 min and 1 day following 10-min ischemia; interestingly, enzymatic activity was increased after 2 and 5 days of reperfusion, and returned to control levels after 10 days. Ischemic preconditioning cancelled the effects of 10-min ischemia on the enzymatic activities. These results indicate that brain ischemia and ischemic preconditioning induce peripheral effects on ecto-enzymes from rat platelets involved in nucleotide metabolism. Thus, ATP, ADP and AMP degradation and probably the generation of adenosine in the circulation may be altered, leading to regulation of microthrombus formation since ADP aggregates platelets and adenosine is an inhibitor of platelet aggregation.
dc.formatapplication/pdf
dc.languageeng
dc.relationBrazilian journal of medical and biological research = Revista brasileira de pesquisas médicas e biológicas. Ribeirão Preto, SP. Vol. 33, no. 11 (Nov 2000), p. 1369-1377
dc.rightsOpen Access
dc.subjectBrain ischemia
dc.subjectIschemic preconditioning
dc.subjectRat platelets
dc.subjectATP diphosphohydrolase
dc.subject5'-Nucleotidase
dc.subjectBioquímica
dc.titleBrain ischemia alters platelet ATP disphosphohydrolase and 5'-nucleotidase activities in naive and preconditioned rats
dc.typeArtigo de periódico
dc.typeNacional


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