Revision as of 17:13, 28 December 2007 by imported>David E. Volk
(PD) Image: National Institute on Alcohol Abuse and Alcoholism Activation occurs when either glutamate (Glu) or N-methyl-d-aspartate (NMDA) and glycine (Gly) bind to the receptor molecule. A channel within the receptor complex enables molecules to cross the cell membrane. Magnesium (Mg) blocks this channel. When Mg is removed from the channel and the receptor is activated, calcium (Ca
2+) and sodium (Na
+) ions enter the cell and potassium ions (K
+) leave. MK-801 prevents the flow of ions across the membrane by binding to a site within the ion channel, thereby blocking NMDA receptor function and protecting the cell against excess activation (i.e., excitotoxicity).
The N-methyl-d-aspartate receptor (NMDA receptor) is the binding site for glutamate, n-methyl-d-aspartate and glycine. NMDA receptors are ionotropic as they allow calcium and sodium ions to flow into the cell while potassium ions leave. This excitatory change hypopolarizes the cell and makes it more likely to fire.
NMDA receptors are implicated in memory and learning through the process of long-term potentiation.