Effects of IC261 on NMDA- and glutamate- evoked excitatory responses in the spinal dorsal horn. (A, B) Optical responses taken before (black lines) and after the addition of IC261 (1 and 3 μM, red and green lines, respectively) in the perfusion solution containing TTX (0.3 μM) for 30 min. NMDA- or glutamate-evoked responses were elicited by the perfusion of 300 μM of NMDA for 30 sec (A) or 3 mM glutamate for 1 min (B) (shown as bars). Optical responses were recorded from both superficial (Ai, Bi) and middle (Aii, Bii) layers of dorsal horns ipsilateral to SNL. (C, D) Summary of the results, testing the effects of IC261 (1 μM, n = 5; 3 μM, n = 9) on the NMDA-evoked responses and IC261 (3 μM; n = 4) on the glutamate-evoked responses. The percentage compared to pre-drug response (as 100%) was shown as % control. *p < 0.05, ***p < 0.001, compared with pretreatment control (Student's t test).