NMDA Receptor

The N-methyl-D-aspartate receptor (also known as the NMDA receptor or NMDAR), aglutamate receptor, is the predominant molecular device for controlling synaptic plasticityand memory function.^[2]

The NMDAR is a specific type of ionotropic glutamate receptor. NMDA (N-methyl-D-aspartate) is the name of a selective agonist that binds to NMDA receptors but not to other 'glutamate' receptors. Activation of NMDA receptors results in the opening of an ion channelthat is nonselective to cations with an equilibrium potential near 0 mV. A property of the NMDA receptor is its voltage-dependent activation, a result of ion channel block by extracellular Mg²⁺ ions. This allows the flow of Na⁺ and small amounts of Ca²⁺ ions into the cell and K⁺ out of the cell to be voltage-dependent.^[3][4][5][6]

Calcium flux through NMDARs is thought to be critical in synaptic plasticity, a cellular mechanism forlearning and memory. The NMDA receptor is distinct in two ways: first, it is both ligand-gated and voltage-dependent; second, it requires co-activation by two ligands: glutamate and either d-serine orglycine.^[7]

Ligand-gated ion channels (LGICs) are a group of transmembrane ion channel proteins which open to allow ions such as Na⁺, K⁺, Ca²⁺, or Cl^- to pass through the membrane in response to the binding of a chemical messenger (i.e. a ligand),^[1] such as a neurotransmitter.^[2]

http://en.wikipedia.org/wiki/NMDA_receptor