Effects of NT compounds on the formalin-induced nociceptive behavioral responses manifested during the inflammatory phase. (a) The antinociceptive response, expressed as mean area under the curve (A.U.C.), is measured during the second phase of the formalin test (21–60 min). Formalin-induced nociceptive behaviors are reduced by i.t. administration of levocabastine (5 μg/kg), JMV-431 (30 μg/kg), and NT69L (5 μg/kg) in comparison to control rats receiving saline injection. (b) Dissociation of phase 2 in early (21–39 min) and late (40–60 min) phases. JMV-431, levocabastine, and NT69L significantly suppressed the tonic pain response in the late phase, but only NT69L was able to induce analgesia in early phase. *P < 0.05 and ** P < 0.01 when compared with the vehicle-treated group (ANOVA followed by Dunnett's multiple comparison test). Data are represented as the average ± SEM.