F1. Studies on Amino Acid Metabolism in Brain in Vivo Accompanied by Conditioned Reflex

Y. TSUKADA
1961 Neurologia medico-chirurgica  
The relationship between amino acid metabolism and brain activities was studied whereby the distribution of amino acids in brain was highly specific compared to the other organs. In order to avoid post-mortem changes, the brain tissue was moved out by rapid freezing technique in liquid nitrogen. Ammonia level determined in brain was increased significantly by 5 sec. electric stimulation through the paw, and returned back to the normal level again quickly. If electric shock was applied for 30
more » ... . continuously, glutamine content was increased without any significant elevation of ammonia. And glutamic acid, aspartic acid and y-aminobutyric acid in brain were not changed under these conditions. When the lighting by the lamp was used as a conditioned stimulus instead of electric shock for conditioned animals, the same results were obtained just as mentioned above. However, ammonia-binding processes might be augmented by daily enforcement of conditioned reflex. From these results, it was found that a biochemical process such as metabolism of ammonia and glutamine was accompanied with the process of establishment of the conditioned reflex. Then, in order to analyze further dynamic equilibrium of these amino acids, double labeling method was performed using C14-glucose and N1-ammonia. Amino acids in brain were separated and purified by columnchromatography based upon Moore & Stein method, and specific activities of C'4 and Nl' were determined by automatic gas flow counter and massspectrometer respectively. The turnover of glutamine in brain was the highest rate compared to other amino acids such as glutamic acid, aspartic acid or y-aminobutyric acid. This might suggest that the synthetic system of glutamic acid and glutamine is operated upon the specific metabolic pool in nerve cell closely relating with carbohydrate metabolism. In the country, metabolic -182-
doi:10.2176/nmc.3.182 fatcat:ozzc7f557je4rjlszyvdjbqo7m