Alteration of GABA system in frog retina following short light and dark adaptations - a quantitative comparison with...

Effect of short light and dark adaptations on retinal GABA and taurine was studied using bull frog (Rana catesbiana). The retinal GABA was increased significantly in light-adapted state, and this increase was accompanied by the increases of L-glutamate decarboxylase (GAD) activity and [3H]-GABA release. The activation of retinal GABA-transaminase succinic semialdehyde dehydrogenase (GABA-T:SSADH) was also observed after a lag period of several hours. Under the same experimental conditions, however, no significant changes were noted in retinal taurine content and cysteine sulfinate decarboxylase (CSD) activity. These findings suggest that a short light adaptation induces differential effects on retinal GABA and taurine, and the activation of GABAergic neurons in the retina may be involved in the process of short light adaptation.