Effects of STZ and DSP-4 on NA and 5-HT content in the lumbar spinal cord. NA (A) and 5-HT (B) content in the lumbar spinal cord at 6 weeks after STZ injection. The mean ± SEM values of 5 rats for each experimental group are shown. The samples were collected from the rats after behavior evaluation (see Methods). *P < 0.05 (Kruskal-Wallis one-way ANOVA) between saline-treated vehicle (Veh) + DW and STZ + DW groups; #P < 0.05; ##P < 0.01 (Mann–Whitney U-test) between saline-treated and DSP-4-treated groups; NS, not significantly different.