Glycine, inhibitory neurotransmitter

Supplementary information

This supplementary information is collated from multiple sources and compiled automatically.

The N-methyl-D-aspartate receptor (NMDAR) subunits including NMDAR2A NMDAR2B GluN2C NMDAR1 NMDAR3A NMDAR3B and GluN2D form a class of ionotropic glutamate receptors and are important in synaptic transmission. These subunits make up NMDAR subtypes where NMDAR1 often combines with other subunits to form receptor complexes. NMDARs are ubiquitously expressed in the central nervous system especially in regions such as the hippocampus and cortex. The molecular mass of NMDAR2A one of the main subunits is approximately 180 kDa. Different subunit compositions determine the receptor's biophysical and pharmacological properties impacting neuronal communication significantly.

Biological function summary

These NMDAR subunits function in mediating excitatory neurotransmission and are fundamental for synaptic plasticity learning and memory processes. The receptor is typically part of a multi-subunit complex that includes various combinations of these subunits allowing a variety of functional properties. The receptors modulate calcium ion influx into neurons therefore playing an important role in the activation of intracellular signaling pathways. Inhibitory neurotransmitters often balance their excitatory effects therefore maintaining neural circuit stability.

Pathways

NMDAR subunits participate in critical signaling pathways like the glutamatergic synapse and calcium signaling pathways. These pathways are essential for neuronal communication and are tightly linked with other proteins such as calcium/calmodulin-dependent protein kinase II (CaMKII) which gets activated by calcium influx. Cross-talk with proteins like PSD-95 can localize and stabilize NMDARs at the synapse further refining the signaling cascade's effects.

NMDAR dysfunctions associate with neurological conditions such as Alzheimer's disease and epilepsy. In Alzheimer's disease the altered NMDAR signaling particularly in the presence of amyloid beta contributes to synaptic failure and neurodegeneration. In epilepsy the imbalance between excitatory and inhibitory neurotransmitters can lead to excessive neuron firing where NMDAR subunits play a part in this pathology. The interaction of NMDARs with proteins like NMDA receptor antibodies is explored in anti-NMDAR encephalitis a disorder that highlights the immune system's impact on these receptors.