Ra. Mafra et al., Glutamate transport in rat cerebellar granule cells is impaired by inorganic epileptogenic agents, NEUROSCI L, 310(2-3), 2001, pp. 85-88
There is evidence that extracellular glutamate levels are elevated in certa
in brain regions immediately prior to and during induction and propagation
of seizures. There appears to be a correlation between the capacity of remo
ving released glutamate and the genesis of epileptiform activity. Some mode
ls make use of metals, such as Co2+ and Ni2+, to induce epilepsy. We used p
atch-clamp recordings to measure the electrogenic glutamate transport in ne
uronal cells. The present results indicate that Co2+ (1 mM) and Ni2+ (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. Ni2+ inhibited glutamate uptake
in a dose-dependent manner. The IC50 value obtained was 66.6 muM and the ma
ximum inhibition was 40%. We conclude that one mechanism that may explain t
he seizures induced by exposure to those divalent cations is inhibition of
the glutamate transporter. (C) 2001 Elsevier Science Ireland Ltd. All right
s reserved.