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Neuron. 1997 Oct;19(4):893-901.

Kainate receptors presynaptically downregulate GABAergic inhibition in the rat hippocampus.

Author information

1
Department of Neural Plasticity, Instituto Cajal, Consejo Superior de Investigaciones Científicas, Madrid, Spain.

Abstract

Using microcultured neurons and hippocampal slices, we found that under conditions that completely block AMPA receptors, kainate induces a reduction in the effectiveness of GABAergic synaptic inhibition. Evoked inhibitory postsynaptic currents (IPSCs) were decreased by kainate by up to 90%, showing a bell-shaped dose-response curve similar to that of native kainate-selective receptors. The down-regulation of GABAergic inhibition was not affected by antagonism of metabotropic receptors, while it was attenuated by CNQX. Kainate increased synaptic failures and reduced the frequency of miniature IPSCs, indicating a presynaptic locus of action. In vivo experiments using brain dialysis demonstrated that kainate reversibly abolished recurrent inhibition and induced an epileptic-like electroencephalogram (EEG) activity. These results indicate that kainate receptor activation down-regulates GABAergic inhibition by modulating the reliability of GABA synapses.

PMID:
9354335
DOI:
10.1016/s0896-6273(00)80970-8
[Indexed for MEDLINE]
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