Figure 3.

Effect on thermal sensitivity in TRPM8 channels opening.

Notes: Injections (10 μL in each group) of only 5% menthol (menthol group), only 2% QX-314 (QX-314 group), a mixture of menthol and QX-314 (menthol/QX-314 group), or the vehicle (vehicle group), were made into rat right plantar hind paws. The menthol/QX-314 group showed more analgesia than the vehicle group at 10 to 60 minutes (P < 0.01). The menthol group showed more analgesia than the vehicle group at 10 to 60 minutes (P < 0.01). No significant difference was seen between the menthol group and the menthol/QX-314 group. The results indicate the independent analgesic effect of menthol.

Abbreviations: QX-314, N-ethyl-lidocaine; TRPM8, transient receptor potential melastatin-8.