ATP diphosphohydrolase (NTPDase 1) in rat hippocampal slices and effect of glutamate on the enzyme activity in different phases of development.
In the present report we describe an NTPDase 1 (ATP diphosphohydrolase; ecto-apyrase; EC 3.6.1.5) in rat hippocampal slices. The effect of glutamate on the ATPase and ADPase activities in rat hippocampal slices of different ages was also studied since adenosine, the final product of an enzymatic chain that includes NTPDase 1 and 5'-nucleotidase, can act upon A1 receptors in turn decreasing the release of glutamate. Hippocampal slices from 7, 14, 20-23 and 60 day-old rats were prepared and ATPase and ADPase activities were measured. The parallelism of ATPase and ADPase activities in all parameters tested indicated the presence of an ATP diphosphohydrolase. In addition, a Chevillard plot indicated that ATP and ADP are hydrolyzed at the same active site on the enzyme. ATPase activity was significantly activated by glutamate in 20-23 and 60 day-old rats, but ADPase activity was not activated. These results could indicate distinct behavior of the ATPase and ADPase activities of NTPDase 1 in relation to glutamate or the simultaneous action of the ecto-ATPase. Activation of ATPase activity by glutamate may constitute an important role in this developmental period, possibly protecting against the neurotoxicity induced by ATP, as well as producing high levels of ADP, by increasing adenosine production, a neuroprotective compound.
Bruno
Alessandra Nejar
AN
Departamento de Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Rua Ramiro Barcelos, 2600-ANEXO, 90035-003, RS, Porto Alegre, Brazil.
Bonan
Carla Denise
CD
Wofchuk
Susana Tchernin
ST
Sarkis
João José Freitas
JJ
Battastini
Ana Maria Oliveira
AM
D000244:Adenosine Diphosphate / Q000378:metabolism; D000251:Adenosine Triphosphatases / Q000378:metabolism*; D000255:Adenosine Triphosphate / Q000378:metabolism; D000818:Animals; D015703:Antigens, CD / Q000378:metabolism*; D001081:Apyrase / Q000378:metabolism; D001665:Binding Sites; D005260:Female; D018698:Glutamic Acid / Q000494:pharmacology*; D006624:Hippocampus / Q000187:drug effects* / Q000201:enzymology / Q000254:growth & development; D006868:Hydrolysis; D066298:In Vitro Techniques; D007700:Kinetics; D051381:Rats; D017208:Rats, Wistar
D015703:Antigens, CD; D018698:Glutamic Acid; D000244:Adenosine Diphosphate; D000255:Adenosine Triphosphate; D000251:Adenosine Triphosphatases; D001081:Apyrase; C067869:CD39 antigen