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. Author manuscript; available in PMC: 2018 Jan 11.
Published in final edited form as: J Neurosci. 2005 Mar 23;25(12):3229–3233. doi: 10.1523/JNEUROSCI.0332-05.2005

Figure 2.

Figure 2

Dose–response effect of morphine-induced analgesia in WT (A) and KI (B, C) animals after chronic naltrindole treatment in WT and KI animals. WT(A) or KI (B, C) animals were implanted with placebo, morphine (A, B), or naltrexone (NLTRX) (C) pellets and infused with either saline or naltrindole (Alzet pump; 10 mg · kg−1 · 24 h−1) for 72 h. Morphine-induced analgesia was measured as described above. There was a significant difference between the placebo- plus saline-treated and the morphine- plus saline-treated groups (p < 0.05). There was no significant difference between the placebo plus saline group and the morphine plus NTI group (p > 0.1). *p < 0.05, significant difference from the placebo-treated group (Student’s t test). No significant difference was observed among the three treatment groups in the naltrexone-pelleted animals (C); p > 0.1 (Student’s t test). Each dose was tested on at least 8–10 animals. % MPE, Percentage of maximum possible effect. Error bars represent SEM.