MK-801 decreases GABA_Areceptor-mediated sIPSCs. A, In a layer V PCC/RSC pyramidal cell held at +30 mV, bath-applied MK-801 (40 μm) decreased the frequency and amplitude of sIPSCs. When BMI (20 μm) was added, sIPSCs were blocked reversibly. Calibration: 500 msec, 0.1 nA. B, In the same cell, the cumulative inter-event interval distribution shows a significant increase in the inter-event interval caused by MK-801 (p < 0.01; K-S test). The cumulative amplitude distribution also shows a significant decrease in amplitude (p < 0.001; K-S test). C, Photomicrograph of the same cell filled with biocytin.I–VI, Cortical lamina.Arrow denotes axon. Scale bar, 100 μm.