Unblocking of NMDA receptor, glutamate binding and activation At resting membrane potential the NMDA receptor is blocked by extracellular Mg2+ ions and therefore is not activated in this state by ligands (glutamate, glycine, NMDA). The voltage block is removed upon depolarization of the post-synaptic cell membrane by the influx of Na+ and efflux of K+ from the cell, Mg2+ is expelled from the NMDA receptor can now be activated by the ligands. The depolarization of the membrane maybe due to activation of Ca2+ impermeable AMPA receptors, which facilitates Na+ influx, contributing to the unblocking of NMDA receptors. Authored: Mahajan, SS, 2009-10-29 Edited: Gillespie, ME, 2009-11-19 Pubmed9481670 Reactome Database ID Release 43438066 Reactome, http://www.reactome.org ReactomeREACT_20594 Reviewed: Tukey, D, 2009-11-17 PathwayStep3324 PathwayStep3323 PathwayStep3326 PathwayStep3325 Activation of NMDA Receptor Membrane depolarization upon activation of Ca impermeable AMPA receptors Unblocking of NMDA receptor Glutamate binding to NMDA receptor