Figure 2.

NPY inhibited recurrent mossy fiber synaptic transmission reversibly. A, Recordings taken from the experiment illustrated in B are NMDA receptor-mediated compound recurrent mossy fiber EPSCs and are the averages of 10 traces. These responses were recorded in the presence of 10 μm NBQX and 30 μm bicuculline at a holding potential of -20 mV. NPY (1 μm) reduced the size of the response markedly and reversibly. The arrowheads indicate stimulus artifacts. Wash, Washout. B, At various times during this representative experiment, a train of 10 stimuli was applied to the mossy fibers at a frequency of 0.1 Hz. Stimuli were presented, and responses were recorded just before the addition of NPY to the superfusion medium (○), during exposure to NPY (•), during washout of NPY from the tissue (▵), and during exposure to d-AP-5 (▴). For each response, peak amplitude is plotted against the time during the experiment at which it was recorded. C, Mean values ± SEM for seven cells to which NPY was applied, three cells that were washed free of NPY (Wash), and five cells to which d-AP-5 was applied after complete or nearly complete recovery from the effect of NPY. ^*p < 0.01 by paired t test with respect to responses recorded just before exposure to NPY.