Metabolism and metabolic response to electrical pulses in white matter from the central nervous system

Abstract

Subcortical white matter of the guinea pig, rabbit and man was capable of respiration and glycolysis in ordinary glucose salines at one-half to two-thirds of the rates found in the cerebral cortex. Under these conditions the guinea pig subcortical white matter resynthesized phosphocreatine to a level of about 0.9 mole/g. In maintaining respiration glucose was replaceable by pyruvate; with succinate and glutamate (but not with acetate and citrate) respiratory rates were greater than in the absence of added substrate, but decreased with time. Glutamate did not, however, support resynthesis of phosphocreatine. Respiration, glycolysis and phosphocreatine formation maintained by glucose responded to application of electrical pulses to the tissue. Pyruvate also permitted response but other substrates examined were ineffective in this respect. Certain of these characteristics were examined also in tissues from the medulla, thalamus, midbrain and sciatic nerve.