Fig. 3.

Agmatine dose-dependently inhibits evoked N-methyl-d-aspartate receptor (NMDAr)-mediated excitatory postsynaptic currents (eEPSC) amplitude, duration, and decay constant in GluN2B-floxed control mice. A: electrically evoked NMDAr-mediated averaged EPSCs, with SE (shading), before (baseline, top trace for each drug) and after application of various concentrations of drug. For each set of traces, drug concentrations from top to bottom are as follows: agmatine 300, 1,000, and 3,000 µM; ifenprodil 1, 10, and 100 µM. Bottom traces show averaged EPSCs for all 3 concentrations. The baseline (no drug) is represented for each treatment group by a red line, the lowest concentration for each drug by a blue line, the intermediate concentration by a yellow-green line, and the highest concentration by a green line. B: concentration-response relationships for absolute values of EPSC amplitude, duration, and decay constant of NMDAR-mediated electrically evoked EPSCs for agmatine (circles) and ifenprodil (triangles). C: transformed concentration-response relationships for different parameters of NMDAr-mediated electrically evoked EPSCs for agmatine (circles) and ifenprodil (triangles) from the data shown in B. D: plots of EPSC difference current traces (baseline trace minus highest drug concentration trace) for agmatine- or ifenprodil-sensitive components of NMDAr-EPSCs based on the data shown in A.