Glutamate-Mediated Alterations in Cellular Redox Status

5 Glutamate-Mediated Alterations in Cellular Redox Status 

In neural cells, the redox status is controlled by the thioredoxin (Trx) and glutathione (GSH) systems that scavenge harmful intracellular ROS. Thioredoxins are antioxidants that serve as a general protein disulphide oxidoreductase (Saitoh et al., 1998). They interact with a broad range of proteins by a redox mechanism based on the reversible oxidation of 2 cysteine thiol groups to a disulphide, accompanied by the transfer of 2 electrons and 2 protons. These proteins maintain their reduced state through the thioredoxin system, which consists of NADPH, thioredoxin reductase (TR), and thioredoxin (Trx) (Williams, Jr. et al., 2000 Saitoh et al., 1998). The thioredoxin system is a system inducible by oxidative stress that reduces the disulfide bond in proteins (Fig. 7.4). It is a major cellular redox system that maintains cysteine residues in the reduced state in numerous proteins. 

Glutathione (GSH) is a tripeptide that acts as a non-enzymic antioxidant in brain tissue (Bains and Shaw, 1997). It exists in at least two pools, 85-90% in 

7 Mechanisms of Neural Injury Caused by Glutamate and Its Receptors 

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