ABSTRACT
N-Methyl-n-aspartate (NMDA) receptors are a subtype of receptors for the major excitatory transmitter in the mammalian central nervous system (CNS), L-glutamate. Receptors for glutamate are divided into two major classes: 1.) ionotropic receptors, which are ligand-gated cation channels comprising the NMD A, AMP A, and kainate subtypes, and 2.) metabotropic receptors, which are a novel, G-protein-coupled receptor family of which eight subtypes have been cloned to date (1). Interest in the development of specific antagonists for NMDA receptors arose from the findings that these receptors play key roles not only in several important physiological functions, particularly synaptic plasticity (2), but also in neuropathological states such as epilepsy and acute neurodegeneration (3).
