The NMDA receptor controls a calcium channel and is normally blocked by magnesium ions.
The NMDA is a type of glutamate receptor that is important in excitatory neurotransmission and also binds N-methyl-d-aspartate. It is important in controlling memory function and the synaptic plasticity. The receptors are located in the post-synaptic membrane of a neuron. Magnesium ions normally prevents the calcium channel of the NMDA from opening in response to glutamate.