The majority of rapid excitatory transmission in the nervous system is mediated by glutamate-activated ion channels. Ionotropic glutamate receptors have been subdivided pharmacologically into AMPA (cx-amino-3-hydroxy-5methyl-Cisoxazole propionic acid), KA (kainate), and NMDA subtypes (Monaghan et al., 1989). These receptors have been implicated in a number of physiological and pathological processes. During development glutamate receptors are involved in neuronal differentiation, migration, and activity-dependent synapse formation (Balazs et al., 1989; Brewer, 1989; Komoru and Rakic, 1993). In mature neurons, long-term potentiation and long-term depression require ionotropic glutamate receptors. Glutamate-gated ion channels also play a central role in mediating the excitotoxic effects of glutamate (Olney, 1990). Pathophysiological processes thought to involve glutamate excitotoxicity and neurodegeneration include epilepsy stroke, Parkinson