D-aspartate, but not L-aspartate, reduced the amplitude of mEPSCsAMPA in cultured hippocampal neurons. (a) An example current trace shows mEPSCsAMPA before, during and after the application of D-aspartate (open bar, 1 mM). Averaged individual mEPSCsAMPA before and during D-aspartate (dotted line, 1 mM), and the superimposed normalized traces are illustrated as insets. (b) Current recordings are mEPSCsAMPA before and during application of L-aspartate (1 mM). (c) Bar graph exhibits that the amplitude of mEPSCAMPA is significantly reduced by D-aspartate (open bars, P<0.01 for 1 and 0.3 mM). L-aspartate has no effect on the amplitude of mEPSCAMPA. Each bar represents averaged data obtained from 3–5 neurons.