Fig. 8. Effects of degrading extracellular D-serine on N-methyl-D-aspartate receptor (NMDAR) and a -amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor (AMPAR) components of excitatory postsynaptic currents (EPSCs) in CA1 neurons of hippocampal slices. (A) Sample EPSCs (average of 10 events) recorded from CA1 pyramidal neurons in the presence of 2-amino-5-phosphonovalerate (APV) (100 m M, upper traces) or 6,7-dinitroquinoxaline-2,3-dione (DNQX) (25 mM, Mg²⁺ free, lower traces) before (control), 40 min after wash in DAAO, and 25-45 min after washout (Wash) of DAAO (0.1 units/ml). Picrotoxin (50 mM) was added to block GABA_A receptor-mediated EPSCs. (B) Summary of results from experiments illustrated in A. The amplitudes of the NMDAR- and AMPAR-EPSCs recorded 25-45 min after wash in 0.1 units/ml DAAO were normalized with that recorded during the control period (before perfusion with DAAO) in the same neuron. Asterisk indicates significant difference from the control (P < 0.01, t test.).