Glutamate is one of the principal neurotransmitters in the brain, but in excess can be highly neurotoxic. In September Nature Medicine Takahiro Takano and colleagues from the New York Medical College, Valhalla, New York, show that in addition to being neurotoxic, glutamate release from glioma cells also promotes growth of malignant gliomas.

Takano et al. used bioluminescence to detect glutamate release from freshly prepared brain slices. They found that implanted glioma cells continue to secrete glutamate and that gliomas with high glutamate release have a distinct growth advantage in host brain that is not present in vitro. In addition, treatment with an antagonist for the glutamate receptor NMDA slowed the growth of glutamate-secreting tumors in situ, suggesting that activation of NMDA receptors facilitates tumor expansion (Nat Med 2001, 7:1010-1015).

These findings suggest a new approach for the treatment of brain tumors, based on antagonizing...