title: Increase of adenine nucleotide hydrolysis in rat hippocampal slices after seizures induced by quinolinic acid.
abstract: Quinolinic acid (QUIN), an endogenous convulsant compound, overstimulates the glutamatergic system stimulating N-methyl-D-aspartate receptors, enhancing glutamate release and inhibiting glutamate uptake. Glutamate releases the neuroprotector adenosine, which in turn reduces glutamate release and depresses the neuronal activity. Additionally, adenine nucleotides are an important source of adenosine, by action of ecto-nucleotidases. Here we evaluated the adenine nucleotide hydrolysis in hippocampal slices of adult rats in different times after seizures induced by QUIN. After 45 min, there was an increase of ATP and ADP hydrolysis. After 5 h, there was an increase of ATP, ADP and AMP hydrolysis. After 12 h, there was an increase only of ATP hydrolysis. After 24 h, all hydrolysis returned to control levels. As slice preparations maintain tissue integrity, this study indicates, more than previously observed with synaptosomal preparations, that the extracellular production of the neuroprotector adenosine may be involved in brain responses to seizures.
authors: Department of Biochemistry, Federal University of Rio Grande do Sul, Porto Alegre, Brazil. ranicolai@cpovo.net
authors: Rafael
authors: R
authors: Nicolaidis
authors: Alessandra Nejar
authors: AN
authors: Bruno
authors: João José Freitas
authors: JJ
authors: Sarkis
authors: Diogo Onofre
authors: DO
authors: Souza
mesh_terms: D000227:Adenine Nucleotides / Q000378:metabolism*; D000818:Animals; D003292:Convulsants / Q000008:administration & dosage; D006624:Hippocampus / Q000201:enzymology / Q000378:metabolism*; D006868:Hydrolysis; D066298:In Vitro Techniques; D007276:Injections, Intraventricular; D017378:Quinolinic Acid / Q000008:administration & dosage; D051381:Rats; D017208:Rats, Wistar; D017470:Receptors, Glutamate / Q000502:physiology; D011983:Receptors, Purinergic / Q000502:physiology; D012640:Seizures / Q000139:chemically induced* / Q000201:enzymology / Q000378:metabolism*
chemical_list: D000227:Adenine Nucleotides; D003292:Convulsants; D017470:Receptors, Glutamate; D011983:Receptors, Purinergic; D017378:Quinolinic Acid