Figure 5

Intradermal injection of TRPV1 receptor antagonist attenuated mechanical hypersensitivity induced by plantar incision. A range of von Frey filaments applied to the incised skin after intradermal injection of vehicle (30 min before and immediately after the surgery) indicated the development of postoperative mechanical allodynia (10, 19, 36, 59 and 80 mN) and hyperalgesia (144, 292, 367 mN) while it did not affect the corresponding contralateral intact hindpaw (n = 6). Intradermal injection of 100 μM SB366791 (30 min before and immediately after the surgery) showed an antinociceptive effect of the TRPV1 receptor antagonist on postoperative mechanical allodynia, while mechanical hyperalgesia remained unaffected (n = 8). *P <0.05, **P <0.01, ***P <0.001 SB366791 injected incised skin versus contralateral; ⁺P <0.05, ⁺⁺P <0.01, vehicle injected incised skin versus contralateral; ^#P <0.05, ^##P <0.01 SB366791 versus vehicle injected incised skin. The time of drug administration is marked by arrow.