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Ascorbate and Glutamate Release in the Rat Hippocampus After Perforant Path Stimulation: A “Dialysis Electrode” Study
Author(s) -
Walker M. C.,
Galley P. T.,
Errington M. L.,
Shorvon S. D.,
Jefferys J. G. R.
Publication year - 1995
Publication title -
journal of neurochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.75
H-Index - 229
eISSN - 1471-4159
pISSN - 0022-3042
DOI - 10.1046/j.1471-4159.1995.65020725.x
Subject(s) - perforant path , glutamate receptor , microdialysis , stimulation , neuroscience , excitatory postsynaptic potential , chemistry , hippocampus , ascorbic acid , biochemistry , central nervous system , biology , inhibitory postsynaptic potential , receptor , food science
Excitatory amino acids have been proposed to play a critical role in the development and maintenance of epileptic seizures and in the development of neuronal damage. Previous animal studies of glutamate during seizures, however, have often failed to measure any rise in glutamate. We have overcome many of the problems of these studies by using an animal model in which epileptic afterdischarges are induced by stimulation of the perforant path, and glutamate and ascorbate are measured using a newly developed microdialysis electrode that combines the advantages of microdialysis and in vivo electrochemistry. We have successfully shown (1) a rise in glutamate after an epileptic afterdischarge, (2) a concomitant initial fall and then a later rise in ascorbate, and (3) progressive dwindling of this effect when afterdischarges are repeated within minutes, despite similar electroencephalographic responses. The possible mechanisms of these effects are discussed and include ascorbate/glutamate heteroexchange, reversal of the glutamate uptake mechanism, and augmentation of glutamate uptake after a seizure.