Metabolism of GABA in retina of diabetic rat

The effect of hyperglycemia on the localization and metabolism of gamma-ami nobutyric acid (GABA) was examined to elucidate the pathogenesis of deterio rations of electroretinogram oscillatory potentials in streptozotocin-induc ed diabetic rats. GABA is localized primarily in amacrine cells in the diab etic retina. GABA content and activities of glutamate decarboxylase (GAD) a nd GABA transaminase (GABA-T) in the retina and superior colliculus (SC) we re determined. GABA content and activities of GAD and GABA-T remained uncha nged in retinas and SCs of diabetic rats. Alterations in the GABAnergic sys tem of the retina could not be observed. GABA metabolism may have no relati on with visual dysfunction in diabetes mellitus.