[Capillary changes in the brain in aging men and their pathophysiological significance].

In autoptic brains of neurologically and psychiatrically healthy patients, aged between 19 and 94 years, structural changes of capillaries and neurons were stereologically investigtaed in different parts of the brain. The results of the putamen reveal a significant increase of the capillary volume and a decrease of the neuronal perikaryon area with age. The cerebral cortex shows only a slight increase of the capillary length, while the nerve cells are significantly smaller. These results lead to the assumption that a decrease of cerebral circulation in old age might be on one hand a symptom of a decreased nerve cell activity but on the other hand the results of changed stereological capillary parameters due to changes of the volume particularly of subcortical brain structures. In animal experiments with functional changes of the brain by hypovolemic oligemia, ischemia and respiratory hypoxia a correlation between electrical brain activity, oxygen consumption, microcirculation and morphometrical capillary parameters could be demonstrated.