Ultrastructural study of enzymes in reactive astrocytes: clarification of astrocytic activity.

Enzymes in reactive of the cerebral cortex were examined at the ultrastructural level in an attempt to resolve some conflicting aspects of astrocytic activity. Correlations between morphological and enzyme changes after injury established that the apparent increase in oxidative enzyme activity was exclusively mitochondrial and not an artefactual reaction product resulting from anoxic cellular damage. Pronounced glucose-6-phosphatase activity within cisternae of an increased amount of the granular endoplasmic reticulum was related to increased glycogen. Further evidence from acid phosphatase activity indicated that astrocytes played a minimal role in phagocytosis.