A, representative recordings in giant striatal interneuron at two different stimulation frequencies: 0.33 and 0.033 Hz. B, the traces from panel A are normalized to the corresponding control amplitude. C, pooled data from 6 independent experiments in giant striatal interneurons. An increase of stimulation frequency results in enhancement of eEPSC inhibition by IEM-1925. D, representative examples of eEPSC trains evoked every 5 s and 60 s in cortical FSIs; only first 8 responses out of 20 are shown. E, summary graph showing the difference in the block of eEPSC amplitude by IEM-1925 in trains delivered with different delays. In both types of experiments the decrease of channel activity resulted in significant decrease of blocking action. (***P < 0.001).