Glycine potentiates NMDA responses in rat hippocampal CA1 neurons

When superfused onto rat hippocampal slices, glycine (0.1-0.5 mM) potentiated the depolarization induced by pressure application of NMDA in normal Krebs solution and the synaptic discharge evoked by stimulation of the Schaffer collateral-commissural inputs to the CA1 pyramidal neurons bathed in Mg2+-free media; the effects were not prevented by strychnine. In addition, glycine partially reversed the blocking effect of D-2-amino-5-phosphonovalerate (AP5) on N-methyl-D-aspartate (NMDA)-induced depolarization. These results show that glycine at relatively high concentrations potentiates the NMDA-mediated response in hippocampal slices.