Failure of kynurenic acid to inhibit amino acid release from the ischemic rat cerebral cortex.
The ability of a broad spectrum glutamatergic receptor antagonist, kynurenic acid (1 and 5 mM) to attenuate release of excitant and other amino acids from the ischemic cerebral cortex was examined in a four vessel occlusion rat model. Kynurenic acid, administered topically onto the cortex in artificial cerebrospinal fluid using bilateral cortical cups, failed to attenuate ischemia-evoked release of aspartate, glutamate, phosphoethanolamine, taurine and at 1 (but not 5) mM it depressed GABA release. There was no effect on basal, pre-ischemic, release. This result suggests that ischemia-evoked amino acid release is not a significant consequence of the activation of ionotropic receptors by synaptically released glutamate.
Phillis
J W
JW
Department of Physiology, Wayne State University School of Medicine, Detroit, MI 48201, USA. jphillis@med.wayne.edu
Song
D
D
Guyot
L L
LL
O'Regan
M H
MH
D000596:Amino Acids / Q000378:metabolism*; D000818:Animals; D002545:Brain Ischemia / Q000378:metabolism*; D002339:Carotid Arteries / Q000502:physiology; D002540:Cerebral Cortex / Q000187:drug effects / Q000378:metabolism*; D002851:Chromatography, High Pressure Liquid; D004569:Electroencephalography / Q000187:drug effects; D018691:Excitatory Amino Acid Antagonists / Q000494:pharmacology*; D007736:Kynurenic Acid / Q000494:pharmacology*; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley; D017470:Receptors, Glutamate / Q000187:drug effects / Q000378:metabolism
D000596:Amino Acids; D018691:Excitatory Amino Acid Antagonists; D017470:Receptors, Glutamate; D007736:Kynurenic Acid