Changes in Nitrogenous Components of Brain Produced by Stimulation of Short Duration

¹ From the Neuropsychiatric Institute, Division of Psychiatry, University of Illinois, Chicago, Illinois

Brain cortex of cats was stimulated through the brachial plexus for 5–30 seconds and the sensory motor area was frozen in situ, the contralateral area frozen 3 seconds before stimulation, serving as control. Stimulation for 20 seconds at 60 cpm produced the following chemical changes per gm wet tissue: a) nonprotein nitrogen increased by 16 µEq; b) nucleic acid nitrogen decreased by 10 µEq; c) lipid nitrogen decreased by 12 µEq. Amino-nitrogen increased in the lipid and nucleic acid fractions and decreased in the acid-soluble fraction. These chemical changes were proportional to the number of effective stimuli and were reversible at rest. It is concluded that nucleic acids and lipids are metabolized in the brain cortex during activity.