title: Effects of blood glutamate scavenging on cortical evoked potentials.
abstract: It is well known that traumatic or ischemic brain injury is followed by acute excitotoxicity caused by the presence of abnormally high glutamate (Glu) in brain fluids. It has recently been demonstrated that excess Glu can be eliminated from brain into blood following the intravenous administration of oxaloacetate (OxAc), which, by scavenging blood Glu, induces an enhanced and neuroprotective brain-to-blood Glu efflux. In this study, we subjected rats to intravenous OxAc administration (i.v., 12.5, 25, and 50 mg/kg, respectively), and studied its effects on somatosensory evoked cortical potentials (EPs). Against our expectation, the amplitudes of EPs did not decrease but increased in a dose- and time-dependent manner after OxAc administration. Similar effects were observed when blood Glu scavenging was enhanced by combining OxAc (12.5 mg/kgbw) with recombinant glutamate-oxaloacetate transaminase (GOT, 0.14 nmol/100 g rat). On the basis of these results, we suggest that the changes of amplitudes of the EPs involve not only a glutamatergic but also the weakening of a GABAergic component. We cannot rule out the possibility that OxAc penetrates into the brain and improves mitochondrial functions.
authors.affiliation: Department of Physiology, Anatomy and Neuroscience, University of Szeged, Közép fasor 52, Szeged, Hungary.
authors.forename: Dávid
authors.initials: D
authors.lastname: Nagy
authors.forename: Levente
authors.initials: L
authors.lastname: Knapp
authors.forename: Máté
authors.initials: M
authors.lastname: Marosi
authors.forename: Tamás
authors.initials: T
authors.lastname: Farkas
authors.forename: Zsolt
authors.initials: Z
authors.lastname: Kis
authors.forename: László
authors.initials: L
authors.lastname: Vécsei
authors.forename: Vivian I
authors.initials: VI
authors.lastname: Teichberg
authors.forename: József
authors.initials: J
authors.lastname: Toldi
mesh_terms: D000818:Animals; D024443:Aspartate Aminotransferase, Cytoplasmic / Q000378:metabolism; D001921:Brain / Q000187:drug effects / Q000378:metabolism*; D005073:Evoked Potentials, Somatosensory / Q000187:drug effects / Q000502:physiology*; D018698:Glutamic Acid / Q000097:blood*; D006863:Hydrogen-Ion Concentration; D008297:Male; D062907:Oxaloacetic Acid / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar
chemical_list: D062907:Oxaloacetic Acid; D018698:Glutamic Acid; D024443:Aspartate Aminotransferase, Cytoplasmic