Effects of IC261 on the primary afferent fiber-evoked spinal excitatory responses. (A, B) Effects of IC261 on the dorsal root-evoked optical responses were assessed in the sham- (A) and SNL- (B) operated mice. Optical responses were taken before (black lines) and after the addition of IC261 (1 and 2 μM) in the perfusion solution for 30 min (red and green lines, respectively). Ipsilateral superficial (Ai, Bi) and middle dorsal horn (Aii, Bii) were analyzed. (C, D) Summary of results, testing the effects of IC261 on sham- and SNL-operated mice in superficial (Ci, Di) and middle dorsal horn (Cii, Dii). n = 6 and 11 for sham and SNL slices, respectively. The percentage compared to pre-drug response (as 100%) was shown as % control. **p < 0.01, ***p < 0.001, compared with pretreatment control (Student's t test).