Ontogenetic profile of ectonucleotidase activities from brain synaptosomes of pilocarpine-treated rats.
Adenosine, a well-known neuromodulator, can act as an endogenous anticonvulsant via the activation of adenosine A1 receptors. This adenine nucleoside can be produced in the synaptic cleft by the ectonucleotidase cascade, which includes the nucleoside triphosphate diphosphohydrolase (NTPDase) family and ecto-5'-nucleotidase. It has been previously reported that ectonucleotidase activities are increased in female adult rats submitted to the pilocarpine model of epilepsy. Several studies have suggested that the immature brain is less vulnerable to morphologic and physiologic alterations after status epilepticus (SE). Here, we evaluate the ectonucleotidase activities of synaptosomes from the hippocampus and cerebral cortex of male and female rats at different ages (7-9, 14-16 and 27-30-day old) submitted to the pilocarpine model of epilepsy. Our results show that ATP and ADP hydrolysis in the hippocampus and cerebral cortex were not altered by the pilocarpine treatment in female and male rats at 7-9, 14-16 and 27-30 days. There were no changes in AMP hydrolysis in female and male rats submitted to the model at different ages, but a significant increase in AMP hydrolysis (71%) was observed in synaptosomes from the cerebral cortex of male rats at 27-30 days. Pilocarpine-treated male rats (60-70-day old) presented an enhancement in ectonucleotidase activities in the synaptosomes of the cerebral cortex (33, 40 and 64% for ATP, ADP and AMP hydrolysis, respectively) and hippocampus (55, 98 and 101% for ATP, ADP and AMP hydrolysis, respectively). These findings highlight differences between the purinergic system of young and adult rats submitted to the pilocarpine model of epilepsy.
de Paula Cognato
Giana
G
Laboratório de Enzimologia, Departamento de Bioquímica, Universidade Federal do Rio Grande do Sul, Rua Ramiro Barcelos, 2600-Anexo, 90035-003, Porto Alegre, RS, Brazil.
Bruno
Alessandra Nejar
AN
Vuaden
Fernanda Cenci
FC
Sarkis
João José Freitas
JJ
Bonan
Carla Denise
CD
D015720:5'-Nucleotidase / Q000378:metabolism*; D000227:Adenine Nucleotides / Q000378:metabolism; D000251:Adenosine Triphosphatases / Q000378:metabolism*; D000367:Age Factors; D000704:Analysis of Variance; D000818:Animals; D000831:Animals, Newborn; D002540:Cerebral Cortex / Q000187:drug effects / Q000201:enzymology; D004195:Disease Models, Animal; D004827:Epilepsy / Q000139:chemically induced / Q000201:enzymology* / Q000473:pathology; D005260:Female; D006624:Hippocampus / Q000187:drug effects / Q000201:enzymology; D008297:Male; D010862:Pilocarpine / Q000031:analogs & derivatives*; D051381:Rats; D012737:Sex Factors; D013574:Synaptosomes / Q000187:drug effects* / Q000201:enzymology
D000227:Adenine Nucleotides; D010862:Pilocarpine; C029118:pilocarpic acid; D015720:5'-Nucleotidase; D000251:Adenosine Triphosphatases; C027201:ectoATPase