EFFECT OF UNILATERAL VISUAL DEPRIVATION AND VISUAL STIMULATION ON THE ACTIVITIES OF GLUTAMATE DECARBOXYLASE, GABA-α KETOGLUTARATE TRANSAMINASE, ASPARTATE AMINOTRANSFERASE AND HEXOKINASE OF THE OPTIC LOBE OF THE ADULT PIGEON

Abstract— A study was made of the effect of unilateral visual deprivation and stimulation upon the activities of glutamate decarboxylase (EC 4.1.1.15), GABA-α-ketoglutarate transaminase (EC 2.6.1.19). aspartate aminotransferase (EC 2.6.1.1) and hexokinase (EC 2.7.1.1) in the optic lobe of the adult pigeon ( Columba Livia ). Visual deprivation was achieved by eyelid suturing or by enucleation and maintained for 1–9 weeks. Unilateral visual stimulation was maintained for 75 min following 72 h in the dark. A small but significant increase was observed in the activities of glutamate decarboxylase and aspartate aminotransferase after unilateral visual stimulation and a decrease after unilateral enucleation. The activities of GABA-α-ketoglutarate transaminase and hexokinase decreased after unilateral visual stimulation and increased after enucleation. Unilateral eyelid suturing resulted in a significant reduction in the activity of glutamate decarboxylase and an increase in the activity of GABA-α-ketoglu-tarate transaminase. Hexokinase activity was, however, unchanged following unilateral eyelid suturing.