Chronic cerebrovascular ischemia in aged rats: effects on brain metabolic capacity and behavior

The objective of this study was to model one of the risk factors for the de velopment of late-onset Alzheimer's disease, decreased cerebral blood flow. Aging rats were tested for visuospatial behavioral deficits after permanen t surgical occlusion of both carotid arteries. This was followed after 4 we eks by quantitative cytochrome oxidase histochemical mapping of metabolic c apacity throughout the brain. The brain regions affected were related to ob served deficits in spatial memory (CAI and posterior parietal cortex), visu ally guided movements (superior colliculus and secondary visual cortex), mo tor coordination (red nucleus), and escape behavior (central gray). The res ults suggest that deficits in visuospatial learning are not exclusively the result of hippocampal dysfunction, but may be directly correlated with alt ered oxidative energy metabolism in other integrative visuomotor regions id entified in this study. It was concluded that chronic cerebrovascular ische mia in this aged rat model produces neurometabolic and behavioral alteratio ns that may be relevant for an increased risk for the development of Alzhei mer's disease. (C) 2000 Elsevier Science Inc. All rights reserved.