title: Effect of hyperglycemia on extracellular levels of amino acids and free fatty acids in the ischemic/reperfused rat cerebral cortex.
abstract: This study analyzed the effects of pre-existing hyperglycemia on the extracellular levels of glutamate, other amino acids and free fatty acids, including arachidonic acid, in the ischemic/reperfused rat cerebral cortex, using a cortical cup technique. Forebrain cerebral ischemia (20 min) was induced by four vessel occlusion. Glucose (3.4 g/kg) was administered 30 min prior to ischemia. Glucose administration had no effect on basal levels of superfusate amino acids and reduced basal levels of linoleic and oleic acids. Cerebral ischemia elicited increased superfusate levels of aspartate, glutamate, phosphoethanolamine, taurine, gamma-aminobutyric acid (GABA) and arachidonic acid when compared with basal levels. Reperfusion caused a further increase in phosphoethanolamine and arachidonic acid levels and transient increases in linoleic, oleic and palmitic acids. Hyperglycemia resulted in significantly reduced levels of glutamate, phosphoethanolamine, GABA and arachidonic, myristic, palmitic, linoleic and oleic acids during ischemia/reperfusion in comparison with the saline-injected ischemic controls. The results indicate that ischemia/reperfusion-evoked increases in the extracellular levels of glutamate, certain other amino acids and free fatty acids are attenuated by prior systemic glucose administration.
authors.affiliation: Department of Physiology, School of Medicine, Wayne State University, 540 E. Canfield, Detroit, MI 48201, USA. jphillis@med.wayne.edu
authors.forename: J W
authors.initials: JW
authors.lastname: Phillis
authors.forename: D
authors.initials: D
authors.lastname: Song
authors.forename: M H
authors.initials: MH
authors.lastname: O'Regan
mesh_terms: D000596:Amino Acids / Q000378:metabolism*; D000818:Animals; D001786:Blood Glucose / Q000378:metabolism; D001794:Blood Pressure; D002540:Cerebral Cortex / Q000378:metabolism* / Q000503:physiopathology; D004569:Electroencephalography; D005230:Fatty Acids, Nonesterified / Q000378:metabolism*; D006943:Hyperglycemia / Q000150:complications / Q000378:metabolism* / Q000503:physiopathology; D002546:Ischemic Attack, Transient / Q000150:complications / Q000378:metabolism* / Q000503:physiopathology; D007773:Lactates / Q000097:blood; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley; D012016:Reference Values; D015424:Reperfusion
chemical_list: D000596:Amino Acids; D001786:Blood Glucose; D005230:Fatty Acids, Nonesterified; D007773:Lactates