Glycine reversal of felbamate hypoxic protection.

We investigated the role of glycine in felbamate hypoxic neuroprotection using the rat hippocampal slice. Following hypoxic exposure, CA1 orthodromic PS recovered a mean 26 +/- 3% of original amplitude; treatment with 1.3 mM felbamate, a recently developed anticonvulsant, increased this recovery to 95 +/- 3%. However, the addition of 10 microM glycine with felbamate during hypoxia, reduced this recovery to 16 +/- 12%. The glycine EC50 for reversal of felbamate hypoxic protection was found to be 4.4 microM. Glycine 10 microM given during hypoxia without felbamate, slightly exacerbated subsequent injury, with 13 +/- 3% recovery seen. Glycine 100 microM given alone under normoxic conditions showed no effect. Reversal of felbamate hypoxic protection was specific for glycine, and was not seen with 50 microM glutamate. These results suggest that felbamate neuroprotection from hypoxia occurs through a glycine interaction.