FIG. 1.

Long-term stability of miniature excitatory postsynaptic current (mEPSC) properties at rest. A: mEPSPs recorded under current-clamp conditions before (control, top trace) or after addition of dl-2 amino 5-phosphonovaleric acid (AP-5, bottom trace). Right: the average (±SE) resting membrane potential before and after addition of AP-5 (P > 0.5). B: control mEPSCs recorded at −82 mV in 2 mM Mg²⁺ under voltage-clamp conditions (top trace). Bottom left traces: events extracted from the section indicated by the dotted lines on an expanded time scale. Bottom right: alignment of 100 mEPSCs (black traces) plus average (gray trace) chosen from the same experiment shown above. C: average mEPSCs corresponding to recordings in the control condition (without AP-5). Left and middle: the averages of events respectively chosen during 8–13 and 23–28 min after reaching whole cell configuration. Both traces were overlapped on the right. To test the stability of the signal, the middle trace was subtracted from left trace, and the resultant trace shown (“difference”). Inset: the comparison of charge transfer at times 8–13 min or 23–28 min (n = 7; P > 0.5).