[Effect of early visual deprivation on GABA transaminase activity in the brain structures of dogs]

Activity of GABA-transaminase was distinctly decreased as compared with controls in all the brain structures studied in animals growing under conditions of early visual deprivation. At the same time, alterations were developed in synthesis of glutamic and aspartic acids and in their ratio. Biosynthesis of glutamic acid was decreased 2-fold in parietal cortex region and in cerebellum of 45 day-old animals, less distinct decrease in the amino acid synthesis was observed in the locomotion brain region of the animals as compared with controls. At an age of 90 days, to the contrary, most distinct decrease (3-fold) in glutamic acid synthesis occurred in the locomotion region and a less distinct decrease - in cerebellum. Synthesis of aspartic acid was less distinctly altered in the deprived animals; it was decreased in cerebellum of both age groups of animals, in parietal cortex region - only in the group of 90 day-old animals and unaltered - in locomotion region of both animal groups. The values of the glutamic/aspartic acid ratio were also decreased. The pattern was quite similar in all the brain structures studied of 45 day-old animals; in the 90 day-old animals the corresponding ratios of the amino acids were increased in cerebellum, only slightly increased - in locomotion region of brain cortex and they were decreased in parietal cortex region.