Glutathione in cognitive function and neurodegeneration

Objective. To review the main findings on the glutathione role in cognitive function and synaptic plasticity processes, as well as, its involvement in neurotrophic and neurodegenerative events in rodents. Development. The tripeptide glutathione and its related enzymes participate in the maintenance of oxidant homeostasis in aerobic cells. Oxidative damage to neuronal components underlies the molecular basis of neuro degeneration and brain aging. Several biomolecules with redox-dependent activity are involved in the neuronal plasticity events that have a role in learning and memory functions. The maintenance of normal glutathione level is important for acquisition, but not consolidation, of spatial memory. Glutathione unavailability induces failures in hippocampal synaptic plasticity mechanisms, which are possibly related to a spatial memory deficit. On the other hand, several studies have suggested that the beneficial effects of neuro trophic treatments are mediated by the modulation of antioxidant defense mechanisms. In fact, nerve growth factor treatment to cognitively impaired rats stimulates glutathione reductase and can prevent the increases in glutathione peroxidase activity, pointing these enzymes as possible intracellular targets of neurotrophin actions on oxidant homeostasis. Conclusion. There is a closed link between glutathione metabolism and oxidant homeostasis, which is expressed in learning and synaptic plasticity deficits in conditions of low glutathione content, as well as, in neurodegeneration-induced glutathione metabolism changes that can be prevented by neurotrophic treatment.