[Biologic plasticity of the aging brain]

The study was performed to elucidate whether the biological plasticity of the brain is reduced with advancing age. Both glucose and energy metabolism in the brain cortex of male Wistar rats aged 6, 12, 24 and 30 months were investigated under normal conditions and in 12 and 24 months old rats under complete cerebral ischemia. Under physiological conditions, glucose, fructose-1,6-phosphate and ATP decreased from 6 to 12 months of age whereas pyruvate, malate and creatine phosphate fell from 12 to 30 months of age. It was concluded that glucose and energy metabolism in brain cortex may be slightly reduced with normal aging. Complete cerebral ischemia caused server reduction in cortical glucose, pyruvate, citrate, alpha-ketoglutarate, malate, oxaloacetate, ATP and creatine phosphate and an increase in fructose-1,6-phosphate, lactate, succinate and AMP. Differences between 12 and 24 month old animals became obvious. It is concluded that aged animals as compared to adult animals are not capable of reacting sufficiently to stress conditions. The biological capacity of the brain is assumed to be reduced with aging.