NEUROBIOLOGY:
Key Brain Receptor Gets an Unusual Regulator
Ingrid Wickelgren
Neuroscientists have unearthed a strange new regulator of nerve cells--a looking-glass molecule not previously known to be made by higher mammals. In the 9 November Proceedings of the National Academy of Sciences, the researchers report that they have cloned a brain enzyme that makes the amino acid D-serine, rounding out their case that this unusual molecule plays a central role in learning and memory as a coactivator of the so-called NMDA receptor--a job previously thought to be performed by another amino acid, glycine. They also traced the enzyme to the same cell type, astrocytes, and the same brain areas where D-serine is found. The newly cloned enzyme, called serine racemase, provides a novel target for drugs to treat a range of neurological conditions in which NMDA receptor malfunction plays a role.
