Nitrogen metabolism of the brain.

Abstract

Summary A. In order to trace the nitrogen metabolism of the brain, ammonia and glutamine of the rat brain was measured by Conway's microdiffusion method, and aminoacid by the paperchromatography. The following data are the return. 1. In order, the normal rat brain, the contents of following substances range as follows: ammonia 0.62±0.042mg %, glutamine 80.4±2.40mg % glutamic acid 158.4 ±5.30 mg %, 7-aminobutyric acid 35.2±2.23 mg % and aspartic acid 30.8±5.10 mg %. 2. The ammonia formation by the rat brain slices was observed for four hours. The decrease in the contents of glutamic acid and glutamine in the slices during the first two hours paralleled with amounts of ammonia formed by them. 3. Ammonia increase proved in the rat brain after the intraperitoneal injection of ammonium chloride was probably removed initially by aspartic acid synthetase and thereafter by glutamine synthetase system. 4. The brain ammonia increased markedly in rats at the time submitted to electroshocks-convulsion, whereas, when the electroshock-convulsion was given twice in succession, this increase in the brain ammonia fell out. However, if the interval between the two shocks be prolonged over three hours, the same phase of increase could be detected. 5. In the case of insulin-hypoglycemic coma, the brain ammonia of rats decreases markedly. 6. During the excitement caused by administration of stimulant, the contents of brain ammonia went increased, while the same were found decreasing in the case of application of depressant. 7. The activity of glutamine synthesis in the rat brain extract treated with intensive electroshock series was found always accentuated than that of normal one. B. The ammonia content in the dog cerebellum was small and the glutamine content in medulla oblongata was also small, while glutamine was contained in a large amount in the cerebellum and 7-aminobutyric acid again in a large quantity in the thalamus. Moreover, the ammonia contents were increased especially in the frontal and parietal lobe at the time submitted to electroshock-convulsion. C. The ammonia contents in the spinal fluid of schizophrenics were greater than that in the patients of other categories. And, in the case of schizophrenics, the one with shorter history of illness gave a value greater than those with longer history. The authors mention here their deep thanks to Drs. S. Kawada, S. Fujita and T. Ota for their assistance through out the entire course of this work.