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. Author manuscript; available in PMC: 2019 Dec 1.
Published in final edited form as: Pain. 2018 Dec;159(12):2512–2521. doi: 10.1097/j.pain.0000000000001355

Figure 1. Morphine administration in the RVM but not the ACC produces analgesia in uninjured rats.

Figure 1.

Tail withdrawal latencies to thermal heat (52°C water bath) were measured at baseline and during a 90 min time course after brain microinjections. (A) Morphine (20 μg/0.5 μl) (N=8) or saline (N=8) administration into the ACC site 1 had no effect. (B) Morphine (20 μg/0.5 μl) (N=8) or saline (N=9) into the ACC site 2 had no effect. (C) Morphine (20 μg/0.5 μl) (N=7) or saline (N=7) into the ACC site 3 had no effect. (D) Morphine (10 μg/0.5 μl) microinjection into the RVM (N=9) significantly increased tail withdrawal latency to thermal heat compared to saline-injected controls (N=7). *P<0.05 (2-way ANOVA with Sidak’s post hoc test). Data are means ± SEM.