The effects of anaesthetics and of convulsants on the lactic acid content of the brain

Abstract

Lactic acid was determined in the brain of the mouse, using liquid air fixation. The mean normal value is 19 mg. per 100 g. brain (wet). This is decreased during anaesthesia (pheno-barbital, amytal, ether); increased by strenuous exercise. Still higher values were found during picrotoxin convulsions, 2-10 min. after onset. At the beginning of the convulsion, brain lactic acid content is normal. During metrazol convulsions an increase occurs in some mice but not in all. Extremely high values occur during cyanide convulsions; normal values during nicotine convulsions. Insulin decreases brain lactic acid. High values cannot be attributed to diffusion of lactate from blood to brain. Possible interpretations are discussed.