Free radicals and glutamate uptake in the retina.

1. Glutamate (Glu) uptake in neurons and astrocytes is essential to prevent the persistence of excitotoxic levels of Glu in the synaptic cleft. 2. We investigated the effect of oxidative stress, which is also involved in ischemia-reperfusion, on the Glu transporter in isolated rat retinal cells. 3. Hydrogen peroxide (H2O2 3-300 microM) decreases the Na+-dependent Glu uptake. This effect is not related to a free radical production and is partly reversed by reducing agents, suggesting a transporter modulation by a redox-related event.