Figure 4.

A, The Y₂ receptor agonist NPY (3-36) (1 μm) replicated the inhibition by NPY of recurrent mossy fiber synaptic transmission, as assessed from its effect on the peak amplitude of the NMDA receptor-mediated compound EPSC. Data were obtained from six granule cells exposed to NPY (3-36) and then to d-AP-5 (50 μm) in the continued presence of NPY (3-36). B, The Y₁ receptor antagonist BIBP3226 (BIBP; 1 μm) did not change the peak amplitude of the NMDA receptor-mediated compound recurrent mossy fiber EPSC significantly when applied by itself, nor did it prevent inhibition by NPY. Data were obtained from six granule cells exposed to BIBP3226, then to NPY (1 μm) in the continued presence of BIBP3226, and finally to d-AP-5 (50 μm) in the continued presence of both BIBP3226 and NPY. Values are means ± SEM; ^*p < 0.01 by paired t test with respect to responses recorded just before the application of NPY receptor ligand.