title: Cerebral oligaemia episode triggers free radical formation and late cognitive deficiencies.
abstract: Sixty minutes of cerebral oligaemic hypoxia, induced by bilateral clamping of the carotid arteries (BCCA) in pentobarbital-anaesthetized normotensive rats, induces a late progressive cognitive decline when compared with sham-operated controls. Analysis at BCCA of hippocampal metabolism using microdialysis showed increased release of glutamate, aspartate and gamma-aminobutyric acid, followed by a progressive rise in the formation of hydroxyl free radicals measured as 2,3-dihydroxybenzoic acid (2,3-DHBA), their reaction product with salicylate, though only in the re-perfusion phase. In the striatum increased dopamine release occurred during BCCA, whereas glutamate and aspartate showed an increase only during the late re-perfusion phase. gamma-Aminobutyric acid (GABA) concentration increased during BCCA and early re-perfusion. An increase in 2,3-DHBA was seen during BCCA, and persisted over 2 h of re-perfusion. Six and 13 months after surgery, though not as early as 3 months, BCCA-treated rats perform worse than sham-operated controls in a water-maze, where decreased swimming speed reveals striatal dysfunction, while hippocampal dysfunction manifested as diminished spatial bias. These results show that cerebral oligaemia, similarly to cerebral ischaemia, leads to increased extracellular dopamine, aspartate and glutamate, and the production of hydroxyl radicals in structures associated with learning and memory processes. Unlike cerebral ischaemia, in cerebral oligaemia the appearance of spatial memory deficits is delayed.
authors.affiliation: Max-Planck-Institute for Experimental Medicine, Göttingen, Germany.
authors.forename: C
authors.initials: C
authors.lastname: Heim
authors.forename: J
authors.initials: J
authors.lastname: Zhang
authors.forename: J
authors.initials: J
authors.lastname: Lan
authors.forename: M
authors.initials: M
authors.lastname: Sieklucka
authors.forename: T
authors.initials: T
authors.lastname: Kurz
authors.forename: P
authors.initials: P
authors.lastname: Riederer
authors.forename: M
authors.initials: M
authors.lastname: Gerlach
authors.forename: K H
authors.initials: KH
authors.lastname: Sontag
mesh_terms: D015102:3,4-Dihydroxyphenylacetic Acid / Q000378:metabolism; D000818:Animals; D001224:Aspartic Acid / Q000378:metabolism; D016893:Carotid Stenosis / Q000150:complications; D003072:Cognition Disorders / Q000209:etiology*; D003342:Corpus Striatum / Q000503:physiopathology*; D004195:Disease Models, Animal; D004298:Dopamine / Q000378:metabolism; D004924:Escape Reaction / Q000502:physiology; D018698:Glutamic Acid / Q000378:metabolism; D006624:Hippocampus / Q000378:metabolism* / Q000503:physiopathology; D006719:Homovanillic Acid / Q000378:metabolism; D062385:Hydroxybenzoates / Q000378:metabolism; D017665:Hydroxyl Radical / Q000378:metabolism*; D002546:Ischemic Attack, Transient / Q000150:complications / Q000378:metabolism* / Q000523:psychology; D007859:Learning Disabilities / Q000209:etiology; D008297:Male; D018782:Maze Learning / Q000502:physiology; D008569:Memory Disorders / Q000209:etiology; D017551:Microdialysis; D018384:Oxidative Stress; D011597:Psychomotor Performance; D051381:Rats; D017208:Rats, Wistar; D011930:Reaction Time; D015427:Reperfusion Injury / Q000150:complications / Q000378:metabolism / Q000523:psychology; D013037:Spatial Behavior / Q000502:physiology; D013550:Swimming; D013997:Time Factors; D005680:gamma-Aminobutyric Acid / Q000378:metabolism
chemical_list: D062385:Hydroxybenzoates; D015102:3,4-Dihydroxyphenylacetic Acid; D001224:Aspartic Acid; D017665:Hydroxyl Radical; D018698:Glutamic Acid; D005680:gamma-Aminobutyric Acid; C009135:2,3-dihydroxybenzoic acid; D004298:Dopamine; D006719:Homovanillic Acid