Figure 1

Intrathecal injection of TRPV1 receptor antagonist attenuated thermal hyperalgesia induced by plantar incision. (A) Vehicle injection 15 min before the surgery (time 0) did not affect the development of thermal hyperalgesia in the incised hindpaw and did not affect the PWL of the contralateral intact hindpaw (n = 6). Intrathecal injection of 100 μM SB366791 prevented the development of thermal hyperalgesia in the operated hindpaw (application 15 min before the surgery) and transiently increased PWL in both hindpaws (n = 6). (B) Intrathecal injection of 10 μM SB366791 (15 min before the surgery, n = 4) showed a moderate analgesic effect on postoperative thermal hyperalgesia when compared to the intrathecal injection of vehicle (n = 6). (C) Intrathecal injection of vehicle (15 min before sham surgery) did not result in any change of the mean PWLs in either hindpaw (n = 6). Intrathecal injection of 100 μM SB366791 (15 min before sham surgery) induced transient thermal hyposensitivity in both hindpaws (n = 6). (D) Intrathecal injection of vehicle (n = 6) or 10 μM SB366791 (n = 4, 15 min before sham surgery) did not change the PWL in comparison to the baseline values. *P <0.05, SB366791 injection: ipsilateral versus contralateral side; ⁺⁺P <0.01, vehicle injection: ipsilateral versus contralateral side; ^#P <0.05, ^##P <0.01, SB366791 versus vehicle injection on the ipsilateral hindpaw; ^XP <0.05, ^XXP <0.01 SB366791 versus vehicle injection on the contralateral hindpaw. The time of drug administration is marked by arrow.