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Simultaneous Expression of Long‐term Depression of NMDA and Long‐term Potentiation of AMPA Receptor‐mediated Synaptic Responses in the CA1 Area of the Kainic Acid‐lesioned Hippocampus
Author(s) -
Bernard Christophe L.,
Wheal Howard V.
Publication year - 1995
Publication title -
european journal of neuroscience
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.346
H-Index - 206
eISSN - 1460-9568
pISSN - 0953-816X
DOI - 10.1111/j.1460-9568.1995.tb01160.x
Subject(s) - ampa receptor , long term depression , long term potentiation , nmda receptor , neuroscience , tetanic stimulation , kainic acid , synaptic plasticity , excitatory postsynaptic potential , chemistry , hippocampus , kainate receptor , glutamate receptor , biology , inhibitory postsynaptic potential , receptor , biochemistry
This study investigates the plasticity of the excitatory synapses in an experimental model of epilepsy, the kainic acid‐lesioned rat hippocampus. Stimulation of afferents in the CA1 area of lesioned hippocampi produced an epileptiform burst of action potentials, with an underlying synaptic potential composed of mixed α‐amino‐3‐hydroxy‐5‐methyl‐4‐isoxazolepropionate (AMPA; 80%) and N ‐methyl‐D‐aspartate (NMDA; 20%) receptor‐mediated components. Tetanic stimulation yielded a long‐term potentiation (LTP) of the mixed AMPA/NMDA receptor‐mediated population excitatory postsynaptic potentials. However, the same type of tetanus resulted in a long‐term depression (LTD) of pharmacologically isolated NMDA receptor‐mediated responses. This LTD occurred independently of the antagonism of AMPA receptors. This suggests that tetanic stimulation produced LTP of AMPA and LTD of NMDA receptor‐mediated responses simultaneously. Finally, both LTP and LTD were shown to be NMDA dependent. This property has profound functional implications for the control of excitatory networks in temporal lobe epilepsy. This work was supported by the Wellcome Trust and the Fondation Simone et Cino Del Duca.