Abundant recent evidence favors a neurotransmitter/neuromodulator role for D-serine. D-serine is synthesized from L-serine by serine racemase in astrocytic glia that synapses, especially in regions of the brain that are enriched in NMDA-glutamate receptors. D-serine is more potent than glycine at activating the ‘glycine’ site of these receptors. Moreover, selective degradation of D-serine but not glycine by D-amino acid oxidase markedly reduces NMDA neurotransmission. D-serine appears to be released physiologically in response to activation by glutamate of AMPA-glutamate receptors on D-serine-containing glia. This causes glutamate-receptor-interacting protein, which binds serine racemase, to stimulate enzyme activity and D-serine release. Thus, glutamate triggers the release of D-serine so that the two amino acids can act together on postsynaptic NMDA receptors. D-serine also plays a role in neural development, being released from Bergmann glia to chemokinetically enhance the migration of granule cell cerebellar neurons from the external to the internal granular layer.
- D-serine N-methyl-D-aspartate receptor
- cx-amino-3-hydroxy1-5-methy1-4-isoxazolepropionate receptor
- serine racemase
ASJC Scopus subject areas
- Cellular and Molecular Neuroscience
- Cell Biology