Effect of a nefopam pretreatment on the transient receptor potential ankyrin 1 (TRPA1) and melastatin 8 (TRPM8) protein expression levels in the dorsal root ganglion (DRG) of streptozotocin (STZ)-induced diabetic rats. Pretreatment with nefopam (30 mg/kg) was performed intraperitoneally 30 min prior to an intraperitoneal injection of STZ (60 mg/kg). To evaluate the expressions of TRPA1 (A) and TRPM8 (B) proteins located in the L4-L6 DRG, a Western blot analysis was performed 4 weeks after the final drug administration. The specific signals for TRPA1 and TRPM8 were quantified and plotted (lower panel). β-actin was used as an internal loading control. STZ injections did not significantly affect the basal level of the TRPA1 protein in the DRG, which was not altered by the nefopam pretreatment. The TRPM8 protein level in the DRG significantly increased 4 weeks after the STZ injection, which was reduced by the nefopam pretreatment. ***
