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. Author manuscript; available in PMC: 2008 Dec 19.
Published in final edited form as: Neuroscience. 2007 Oct 5;150(4):807–817. doi: 10.1016/j.neuroscience.2007.09.060

Figure 1. Antihyperalgesic effect of intrathecal deltorphin II in C57BL/6 mice.

Figure 1

A, C57BL/6 mice were injected with CFA in the plantar surface of the right hindpaw. Seventy-two hours after CFA injection, the latency to paw withdrawal (in s) was tested every 15 min (from 15 to 60 min) after intrathecal injection of saline (5 μl) or deltorphin II (0.1, 0.25, 1, 2.5 μg). Intrathecally-administered deltorphin II induced a dose-dependent relief of thermal hyperalgesia (ipsilateral hindpaw). The antihyperalgesic effect of deltorphin II peaked 15 min after the injection. −72 h indicates the baseline for the latency to paw withdrawal before CFA injection and time 0 the latency to paw withdrawal just before injection of saline or deltorphin II. Number in parenthesis indicates the number of animals in each group. B, Graphic determination of the effective dose of deltorphin II (ED50) inducing a 50% relief of thermal hyperalgesia. C, No effect of deltorphin II was observed on the contralateral hindpaw. ***, p < 0.001 when compared to latency to paw withdrawal of ipsilateral hindpaw 72 h after CFA injection (PostCFA, white bar); one-way ANOVA followed by Bonferroni’s multiple comparison test.