A Source of Ammonia and Changes of Protein Structure in the Rat Brain during Physical Exertion

Abstract

WE have already shown that functional activity of the brain associated with diffuse neuromuscular activity (physical exertion by swimming) influences numerous biochemical processes in the brain. Certain metabolic processes in the brain are probably used for meeting the energy requirements of the nervous tissue during increased functional activity of the brain connected with the carrying out of physical exertion. This is shown by the fall of the actual concentration of glycogen, glucose and lactic acid in the brain¹. Since, during increased functional activity of the brain, an increased amount of ammonia is produced, which is toxic to the nervous tissue, processes of detoxication of ammonia bound by free glutamic acid to free glutamine occur in the brain³. An extensive literature shows that functional activity and various modes of excitement of nervous tissue are always connected with the formation of ammonia². The sources of ammonia, and the biochemical and physiological significance of the process of ammonia formation in nervous tissue during functional activity, however, have not been definitely established. The present investigation was undertaken to contribute to the clarification of this question.