Figure 6. E_IPSP and I_NaP act synergistically to promote spinal hyperexcitability.

(A) Representative L5 ventral root activities (VR L5) evoked by a supramaximal stimulation (St.) of the ipsilateral dorsal root in spinal cords isolated from intact rats (4–5 d old, n = 11 rats) before (black) and after (gray) the application of veratridine (60 nM, 30 min) followed by the superfusion (red) of DIOA (30 µM, 30 min). (D) Same experiments (n = 6 rats) as in (A) but by applying DIOA (gray) before veratridine (red). (B,E) Average peristimulus time histogram (PSTH, bin width: 20 ms) of dorsal root evoked L5 ventral root responses recorded either in the presence of veratridine or DIOA alone (gray), or in the presence of both (red). (C,F) Group means quantification of events per rat detected over time windows of 10–40 ms and 500–15,000 ms post-stimulus for SLR and LLR, respectively. *p<0.05, **p<0.01, ***p<0.001 repeated measures one-way ANOVA. (G) Representative spontaneous activities recorded on L5 ventral root (VR L5) in spinal cords isolated from intact rats (4–5 d old, n = 19 rats) before (black) and after (red) the superfusion of 60 nM veratridine with 30 µM DIOA (30 min). (H) Group means quantification of spontaneous activities. **p<0.01, ***p<0.001 Wilcoxon paired test. Data are mean ± SD. Underlying numerical values can be found in the Figure 6—source data 1.