Postnatal development of ATPase-ADPase activities in synaptosomal fraction from cerebral cortex of rats.
ATPase-ADPase activities in synaptosomes from cerebral cortex was measured in rats of various ages (0-, 7-, 10-, 14- and 21- and 60-90-days). The activities (nmol Pi/min/mg) increased steadily from birth, reaching maximum values at 21 days of age. The increase was primarily due to increases in Vmax; the Km values are the same from birth until adult age. The developmental profile was similar for ATPase-ADPase activities and acetylcholinesterase from the same fraction. Several specific ATPase inhibitors and Ap5A (P1P5-di(adenosine-5)-pentaphosphate) did not interfere with the hydrolysis of ATP and ADP at all ages studied, suggesting that classical ATPases and adenylate kinase were not involved in the degradation of both nucleotides by synaptosomal fraction in the assay conditions. Other phosphatases were also ruled out. It is conceivable that ATPase-ADPase activities play an important role in neurotransmitter metabolism.
Müller
J
J
Departamento de Bioquimica, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil.
Rocha
J B
JB
Battastini
A M
AM
Sarkis
J J
JJ
Dias
R D
RD
D000251:Adenosine Triphosphatases / Q000378:metabolism*; D000375:Aging / Q000378:metabolism*; D000818:Animals; D000831:Animals, Newborn; D001081:Apyrase / Q000378:metabolism*; D001835:Body Weight; D001921:Brain / Q000033:anatomy & histology / Q000254:growth & development; D002540:Cerebral Cortex / Q000033:anatomy & histology / Q000201:enzymology* / Q000254:growth & development; D007700:Kinetics; D009929:Organ Size; D051381:Rats; D017208:Rats, Wistar; D013574:Synaptosomes / Q000201:enzymology*
D000251:Adenosine Triphosphatases; D001081:Apyrase