Thinking outside the synapse: glycine at extrasynaptic NMDA receptors

Area of Science:

• Neuroscience
• Molecular Biology
• Receptor Pharmacology

Background:

• Extrasynaptic NMDA receptors (NMDARs) play crucial roles in neuronal function and dysfunction.
• The endogenous coagonist for extrasynaptic NMDARs has remained largely unidentified, hindering research into their specific functions.
• Synaptic NMDARs are known to coactivate with d-serine.

Discussion:

• Papouin et al. demonstrate that glycine is the endogenous coagonist for extrasynaptic NMDARs.
• This finding contrasts with the established role of d-serine as the coagonist at synaptic NMDARs.
• The study utilized enzymatic degradation of endogenous glycine to investigate its role.

Key Insights:

• Glycine is identified as the primary endogenous coagonist for extrasynaptic NMDARs.
• This establishes a key difference in NMDAR activation mechanisms between synaptic and extrasynaptic locations.
• The research provides a tool (glycine degradation) to probe extrasynaptic NMDAR function.

Outlook:

• Further research can now explore the specific physiological roles of extrasynaptic NMDARs mediated by glycine.
• Understanding these roles may reveal new therapeutic targets for neurological and psychiatric disorders.
• This work opens avenues for investigating glycine's involvement in NMDAR-related pathologies.