Effects of intrathecal SNC80 on formalin-induced paw-flinching behavior. (A) Time course over 60 minutes of flinches after formalin (5%, 50 μl) paw injection in rats with intrathecal injection of SNC80 (100, 200 μg) or vehicle. (B) Cumulative flinches in each phase, phase 1: 1–9 minutes; phase 2: 10–60 minutes. Intrathecal 200 μg, but not 100 μg, of SNC80 reduced both phase 1 and phase 2 of formalin-induced paw flinching. Data are presented as mean ± S.E.M. n = 4–6, *P < 0.05.