Fig. 1
NMDAR single-channel activity is down-regulated by bath application of DHPG or high NMDA/glycine. NMDAR-mediated currents evoked by including NMDA (10 μM) and glycine (3 μM) in recording pipettes in the cell-attached configuration. Recorded NMDARs were isolated by the patch electrode from the extracellular bath environment (see cartoons in a and e). a an example of records of NMDA single-channel open probability (P o , bin: 10 s) before, during and after bath application of DHPG (50 μM). b examples of recorded single-channel current traces. O: Open level; C: Closed level. An example of I-V relationships before (open circles) and post (filled triangles) DHPG application is shown in (c). d summary data (mean ± SEM) showing relative changes in overall P o , mean open time (t o ), and lengths of burst (B s ), cluster (C s ) and super-cluster (S c ) when compared with that before the bath application of DHPG (control, dashed line). Effects of DHPG (50 μM) were also examined in neurons treated with MPEP (10 μM, DHPG/MPEP), DIP (50 μM, DHPG/DIP), or sDIP (50 μM, DHPG/sDIP). Examples of records of NMDA single-channel open probability, single-channel current traces and I-V relationships before and during bath application of a high concentration of glycine (100 μM) in the presence of 1 mM NMDA (N + G) are shown in (e, f and g), respectively. h summary data showing relative changes in channel activity when compared with that before the bath application of glycine (control, dashed line). Effects of bath application of N + G were also examined in neurons treated with L689560 (1 μM, N + G/L689560), DIP (N + G/DIP) or sDIP (N + G/sDIP). Values in brackets indicate number of patches recorded. *: P < 0.05 (paired t-test) in comparison with control before bath application of DHPG or glycine