Figure 2.

The QX-314/capsaicin combination reduced the sensitivity of rats with injured sciatic nerves to mechanical and thermal stimuli. The normalized peak threshold (A) and the time course of the threshold to mechanical stimuli (B) show that perisciatic injection of QX-314 (0.2 %) with capsaicin (0.5 mg/ml) increased the withdrawal threshold to mechanical stimulation for ~1 h. The mechanical threshold was also increased by lidocaine (2 %), however lidocaine also caused motor deficits (data not shown). QX-314 alone or capsaicin alone dramatically lowered the mechanical threshold. The normalized peak latency (C) and the time course of the latency to thermal stimuli (D) show that perisciatic injection of the QX-314/capsaicin increased the withdrawal threshold to thermal stimulation. The thermal threshold was decreased by QX-314 and capsaicin alone. The peak response to each drug during the time course was normalized to facilitate comparisons between the different groups and graphed as the normalized threshold or latency (A and C). For the normalized threshold and latency (A and C), single asterisks indicate that p < 0.05 and double asterisks indicate that p < 0.01 compared to the baseline before the injection. For the time courses (B and D), an asterisk indicates that p < 0.05 for the QX-314/capsaicin combination. For each group, n = 6. Cap = capsaicin; Lido = lidocaine; QX = QX-314;Veh = vehicle.