Summary
Glutamate-gated channels that act as coincidence detectors by needing both ligand and depolarisation.
In depth
Block by Mg2+ is relieved on depolarisation; with glutamate bound, channel opens and admits Ca2+, initiating signalling cascades (CaMKII). Overactivation causes excitotoxicity in stroke. Ketamine blocks NMDA receptors and has rapid antidepressant effects.
NMDA receptors are coincidence detectors needing glutamate and depolarisation. They are crucial for LTP. Overactivation kills neurons.
Remember: ketamine and PCP block NMDA receptors.
The NMDA receptor is a coincidence detector: it requires glutamate binding (presynaptic activity) and postsynaptic depolarisation to remove Mg2+ block, and also needs co-agonists glycine or D-serine. Ca2+ entry activates CaMKII and other signalling, leading to LTP, while smaller Ca2+ rises favour LTD. Subunit composition (GluN2A versus GluN2B) changes kinetics and plasticity, with GluN2B decreasing over development.
Overactivation causes excitotoxicity in stroke and neurodegeneration. Antagonists include ketamine (a dissociative anaesthetic that rapidly relieves depression in some patients), PCP and memantine (used in Alzheimer disease). Anti-NMDA receptor encephalitis, an autoimmune disease, causes psychosis and seizures. Schizophrenia is linked to NMDA hypofunction.
Example: ketamine's fast antidepressant effect is being studied in mechanism and therapy.
Frequently asked questions
What is NMDA Receptors?
Glutamate-gated channels that act as coincidence detectors by needing both ligand and depolarisation.
Which area of biology covers NMDA Receptors, and how advanced is it?
NMDA Receptors is one of the 54 topics in Neuroscience. It is rated Advanced, so it suits learners who want specialist depth. Related topics in this area include Excitatory and Inhibitory Synapses, Neurotransmitters, Neuropharmacology.
Can you give an example of NMDA Receptors?
Memantine is used in Alzheimer's.
What should I learn before NMDA Receptors?
Work through the Beginner topics in Neuroscience first, such as Nervous System, Neuron, Central and Peripheral Nervous Systems, then return to NMDA Receptors. Advanced topics assume the Intermediate vocabulary.
What topics are related to NMDA Receptors?
The closest topics to NMDA Receptors are Excitatory and Inhibitory Synapses, Neurotransmitters, Neuropharmacology, Synaptic Transmission. Comparing them side by side is a good way to see how the ideas connect.
How can I check that I understand NMDA Receptors?
Read the summary and the in-depth section, then use the quick check on the interactive lesson for NMDA Receptors. To practise the whole of Neuroscience, use the Neuroscience quiz.
How is NMDA Receptors different from Excitatory and Inhibitory Synapses?
NMDA Receptors: Glutamate-gated channels that act as coincidence detectors by needing both ligand and depolarisation. Excitatory and Inhibitory Synapses: Excitatory inputs depolarise the postsynaptic cell while inhibitory ones hyperpolarise it. Read both side by side and note what each one explains.
How should I study NMDA Receptors step by step?
First, read the summary and write the definition in your own words. Second, read the in-depth section and note any example. Third, compare it with Excitatory and Inhibitory Synapses and explain the difference aloud. Finally, take the Neuroscience quiz and come back to this page for any question you miss.