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Weiczner R, Krisztin-Peva B, Mihaly A: Blockade of AMPA-receptors attenuates 4-aminopyridine seizures, decreases the activation of inhibitory neurons but is ineffective against seizure-related astrocytic swelling. Epilepsy Res. 2008 Jan;78(1):22-32. Epub 2007 Nov 26. The neurotransmitter glutamate plays a pivotal role in the development of the neuropathological sequelae following acute seizures. Our previous data proved the efficacy of the NMDA-receptor antagonists on the symptoms, survival and neuronal activation in the 4-aminopyridine- (4-AP) induced seizures. In this study, we examined the effects of two different doses of a non-competitive, selective, allosteric AMPA-receptor antagonist, GYKI 52466. GYKI 52466 was effective in prolonging the latency to generalised seizures and reduction of seizure mortality. However, the effects on neuronal c-fos expression and astrocyte swelling were complex. The 25mg/kg dose of GYKI 52466 was effective in reducing the c-fos immunoreactivity (IR) in the hippocampus only. In the neocortex the overall c-fos-IR cell counts were increased significantly. Investigation of the neocortical parvalbumin-containing interneuron population proved that GYKI 52466 decreased c-fos expression. The 50mg/kg dose of GYKI 52466 significantly reduced the c-fos-IR in the neo- and allocortex, not only in principal neurons, but also in the parvalbumin-positive interneurons. The GYKI 52466-pretreatment did not prevent the astrocyte swelling in the investigated cortical areas; thus we conclude that the AMPA-receptors have little if any involvement in the in the mediation of neuropathological alterations in acute convulsions. |
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