Nitrogen Metabolism of the Brain

In case of the intraperitoneal application of ammonium chloride, ammonia of the rat brain was measured by Conway's microdiffusion method, and amino acid by paperchromatography; the following results were obtained.1) During the ammonium chloride convulsions (induced by injection of 1ml. of 10% NH4Cl), the ammonia and aspartic acid contents of the rat brain increased remarkably, while glutamic acid, glutamine and γ-amino butylic acid contents decreased.2) Ammonia and amino acids were estimated in 3 hours after NH4Cl injeetion (1ml. of 5% NH4Cl), and the following data were obtained.a. Ammonia level remarkably rose five minutes after injection, and gradually returned to normal level 3 hours after.b. Glutamic acid decreased.c. The rise of glutamine level found 10 minutes to 1 hour after the application.d. γ-amino butylic acid decreased.e. Aspartic acid level rose on early period.The Conclusion is as follows:1) In the rat brain, the free ammonia increased after NH4Cl injection.2) Ammonia increased after NH4Cl injection was probably reduced, initially by aspartie acid synthetase system and thereafter by glutamine synthetase syestm.