ABSTRACT
Oxidative stress is defined as a shift in the normal prooxidant/antioxidant balance in favor of prooxidants (1). Physiological processes such as signal transduction (2) and pathophysiological conditions such as neurodegeneration (3) have been suggested to be mediated by oxidative stress, although in most cases the mecha nisms remain poorly understood. In recent years, there has been growing evidence suggesting that glutamate neurotoxicity is mediated by oxidative stress (3-6). Glutamate is the major excitatory neurotransmitter in the central nervous system (CNS) (7), but under certain conditions it can be toxic to neural cells. Exposure of cultured neurons to elevated glutamate levels results in both apoptotic and necrotic cell death (8,9). Glutamate is believed to play an important role in neuro degeneration associated with Alzheimer’s disease (10,11), Parkinson’s disease (12,13), and cerebral ischemia (14). Understanding the mechanisms of glutamate neurotoxicity may, therefore, have important clinical ramifications for many neurodegenerative disorders.
