Inverse enzymatic changes in neurons and glia during increased function and hypoxia.

Following stimulation of the vestibular nerve in the rabbit, respiratory enzyme activities increased in Deiters' nerve cells. The anaerobic glycolysis, measured as 10(-4) microl CO(2) per hour per cell, was found to decrease concomitantly by 25 to 40 per cent, suggesting a Pasteur effect. By contrast, in the surrounding glia the anaerobic glycolysis increased and the respiratory enzyme activity decreased, suggesting a Crabtree effect. The evidence is discussed for a regulatory metabolic mechanism operating between the neuron and its glia. Hypoxia of 8 per cent O(2) caused an increase of both oxygen consumption and CO(2) production in the nerve cells, but did not change the glia values.