Effects of DSP-4 on analgesic effects of DLX in STZ-treated rats. Effects of DLX treatment on thermal hyperalgesia (A) and mechanical allodynia (B) in the rats treated with STZ (a) and vehicle (b) at 6 weeks after STZ injection. The control rats received equal volumes of distilled water (DW) instead of DLX. Thermal hyperalgesia was assessed at 60 min before (pre-DLX or DW, white columns) and 60 min after injection of DLX (post-DLX, dark gray columns) or DW (post-DW, light gray columns). Mechanical allodynia was assessed at 30 min before (pre-DLX or DW) and 90 min after injection of DLX (post-DLX) or DW (post-DW). Circles represent the values at pre-DLX and post-DLX (or DW) obtained from each rat. Bars indicate the mean values at pre-DLX and post-DLX (or DW). Each experimental group was composed of 5 rats. The differences in the values of pre-DLX and post-DLX were compared by Wilcoxon signed-rank test. (c) Change in paw withdrawal latency (A) and threshold (B) by DLX in the rats treated with STZ and vehicle. Change in paw withdrawal latency and threshold by DLX (y-axis for Ac and Bc) was calculated as the value of post-DLX divided by the value of pre-DLX. The mean ± SEM values of 5 rats for each experimental group are shown. The differences in the values were compared using the Mann–Whitney U-test.