Fig. 4.

Effect of MLA on spontaneous and evoked EPSCs. In this experiment the effect of MLA superfusion (150 nm) was determined simultaneously on responses evoked by electrical stimulation and on spontaneously occurring events. A, Time course in the decline of the evoked synaptic potential (E-EPSC) during superfusion with MLA (the beginning of superfusion was at 1 min). Traces displayed at the top are averages of each successive pair of points. B, Amplitude and time of occurrence of each of the spontaneous events recorded in the same experiment; the records at the top are averages of all of the single events obtained during the same epochs as the evoked responses in A (the last record is a comparable average of baseline noise; no events could be detected).