Ischemia and aging brain. Studies on glucose and energy metabolism in rat cerebral cortex.

Age has been considered to be a crucial risk factor for brain ischemic insults and their mortality. Brain ischemia has been found to cause severe abnormalities in glucose metabolism, energy metabolism and related metabolism, thus damaging the structure and function of brain cells. To study the effect of age and ischemia on brain glucose and energy metabolism, investigations were performed on one-and two-year-old male Wistar rats, the latter of which can be designated as aged. In both age groups, ischemia resulted in a depletion of glucose, OAA, ATP AND CRP, a diminution of Pyr, Citr and alpha-Keto and an accumulation of FDP, Lact, Succ, ADP and AMP in brain cortex. During ischemia, differences between the two age groups became most obvious in the concentrations of Glu, FDP, DHAP, Lact, Succ, Mal, ADP and AMP. In general, the metabolic changes in both age groups point to an increased glycolytic flux which may be less accelerated in the aged group, to an inhibition of the starting reactions of the tricarboxylic acid cycle more severe in aged animals, to a preponderance of anaplerotic reactions in this oxidative system more pronounced in the two-year-old group and to a loss of AMP in the same age group. The age-related metabolic variations measured may indicate that with age the biological plasticity of the brain may be reduced to meet emergency conditions.