title: Glutamate transport in rat cerebellar granule cells is impaired by inorganic epileptogenic agents.
abstract: There is evidence that extracellular glutamate levels are elevated in certain brain regions immediately prior to and during induction and propagation of seizures. There appears to be a correlation between the capacity of removing released glutamate and the genesis of epileptiform activity. Some models make use of metals, such as Co(2+) and Ni(2+), to induce epilepsy. We used patch-clamp recordings to measure the electrogenic glutamate transport in neuronal cells. The present results indicate that Co(2+) (1 mM) and Ni(2+) (5 mM) blocked glutamate transport by 17.6+/-3.9% (n=5, P<0.05) and by 31.8+/-6.2% (n=7, P<0.05), respectively. Ni(2+) inhibited glutamate uptake in a dose-dependent manner. The IC(50) value obtained was 66.6 microM and the maximum inhibition was 40%. We conclude that one mechanism that may explain the seizures induced by exposure to those divalent cations is inhibition of the glutamate transporter.
authors.affiliation: Departamento de Fisiologia, CCBI, Universidade Federal de Alagoas, Maceió-AL, Brazil.
authors.forename: R A
authors.initials: RA
authors.lastname: Mafra
authors.forename: D A
authors.initials: DA
authors.lastname: Araújo
authors.forename: P S
authors.initials: PS
authors.lastname: Beirão
authors.forename: J S
authors.initials: JS
authors.lastname: Cruz
mesh_terms: D027322:Amino Acid Transport System X-AG / Q000378:metabolism; D000818:Animals; D001692:Biological Transport / Q000187:drug effects / Q000502:physiology; D002478:Cells, Cultured; D002531:Cerebellum / Q000166:cytology*; D003035:Cobalt / Q000494:pharmacology*; D003292:Convulsants / Q000494:pharmacology*; D004827:Epilepsy / Q000139:chemically induced / Q000378:metabolism; D018698:Glutamic Acid / Q000378:metabolism*; D009474:Neurons / Q000378:metabolism*; D009532:Nickel / Q000494:pharmacology; D018408:Patch-Clamp Techniques; D051381:Rats; D017208:Rats, Wistar
chemical_list: D027322:Amino Acid Transport System X-AG; D003292:Convulsants; D003035:Cobalt; D018698:Glutamic Acid; D009532:Nickel