Figure 3. The analgesic effect of topical borneol in TRPA1^−/− mice and wild‐type (WT) mice with pharmacologically inhibited GABA_A .

• A, B
  Quantification of the borneol effect on capsaicin (Cap)‐induced nociceptive responses in TRPA1^−/− mice (A) and WT mice (B). The experimental procedure was the same as that in Fig 2A.
• C
  Quantification of the borneol effect on CFA‐induced thermal hyperalgesia in TRPA1^−/− mice. The experimental procedure and statistical analysis were the same as that in Fig 2E. n = 8 mice for each group.
• D, E
  Quantification of the effect of intrathecal injection of GABA_A antagonist bicuculline on borneol‐induced analgesia in the capsaicin model. After intrathecal injection of control saline or bicuculline in WT mice, ethanol (D) or 15% borneol (E) was applied to a hindpaw for a total of three times. After 10 min, 100 μM Cap was injected into the paw, and paw licking and lifting time was measured. Saline was used as a control to bicuculline, and ethanol was used as a control to borneol.
• F
  A positive control experiment of the intrathecal injection of bicuculline in WT mice. After intrathecal injection of control saline or of the GABA_A agonist muscimol with or without bicuculline, 100 μM Cap was injected into the paw. Paw licking and lifting time was measured within 5 min. Saline was used as a control to muscimol and bicuculline.

Data information: In (A, B, D–F), the number of mice is indicated on top of each bar. Statistical significance was evaluated using two‐tailed t‐test. *P < 0.05; ***P < 0.001; ^# P < 0.05; ns indicates P > 0.05; the exact P‐values are indicated in Appendix Table S1. All the data are presented as the mean ± standard error of the mean (SEM).