Fig. 2.

Dose-response study of NAX 409-9 in the carrageenan model of thermal hyperalgesia. Male CF-1 mice received intraplantar carrageenan (25 μl, 2% solution in saline) in the right (ipsilateral) hindpaw. Three hours later, both left (contralateral) and right hindpaws were subjected to thermal stimulation (focused light beam beneath glass platform). The paw withdrawal (latency) is shown for each paw in each group. One hour prior to latency determination, mice received NAX 409-9 (intraperitoneal injection) at 1 (N = 8), 4 (N = 12), 6 (N = 12), 8 (N = 12), 12 (N = 18), or 20 mg/kg (N = 8), or vehicle (1% Tween 20 in saline, N = 19). NAX 409-9 produced a dose-dependent increase in latency to paw withdrawal in the ipsilateral paw, starting at doses above 6 mg/kg. **P < 0.01 compared with vehicle, 1 mg/kg, and 4 mg/kg ipsilateral latencies. ^††P < 0.01 compared with contralateral latencies in the same treatment group. ^#P < 0.05 compared with 12 mg/kg on the same side paw. ^P < 0.05 compared with 20 mg/kg on the same side paw.