GluR5 is present in a subset of interneuronal kainate receptors. Effects of UBP 302 on agonist-induced currents were examined. UBP 302 had no effect on AMPA-induced currents shown over the entire application of AMPA (A₁) and at higher temporal resolution around the antagonist application (A₂). B, The nonselective KAR agonist domoate induced an inward current that was primarily insensitive to the GluR5-selective antagonist UBP 302. C, ATPA, an agonist that selectively activates GluR5-containing KARs, evoked an inward current that was completely blocked by UBP 302. D, A summary of the effect of UBP 302 on various agonist-induced currents. E, Effects of UBP 302 on agonist-induced currents were also examined using rapid application methods. A brief puff (10–20 ms) of 100 μm kainate was applied to the cell and induced an inward current in the absence (black) and presence (gray) of UBP 302. CTZ, Cyclothiazide; ctl, control.