Antinociceptive Effects and Interaction Mechanisms of Intrathecal Pentazocine and Neostigmine in Two Different Pain Models in Rats

Figure 5

To evaluate the possible interaction mechanism between pentazocine and neostigmine, nor-Binaltorphimine (nor-BNI, 10 μg), CTAP (10 μg), naloxone (NAL10 μg), and atropine (ATR 10 μg), were intrathecally administered 30 minutes before the administration of the pentazocine (30 μg)-neostigmine (3.0 μg) mixture. (a) Nor-BNI, naloxone, and atropine significantly antagonized the antinociception of the pen-neo mixture in the first phase of formalin pain (One-way ANOVA, F_5,54 = 36.437, ). (b) Nor-BNI, naloxone, and atropine significantly antagonized the antinociception of the pen-neo mixture in the second phase of formalin pain (One-way ANOVA, F_5,54 = 62.32, ). (c) Nor-BNI, naloxone, and atropine significantly antagonized the antinociception of the pen-neo mixture in the plantar incision pain model (One-way ANOVA, F_5,54 = 16.88, ). , , vs. Pen + Neo group, n = 10 rats in each group. Each bar represents the sum of flinches in (a) phase (I), (b) phase II, and (c) the mechanical withdrawal threshold (mean ± SEM) from 10 rats.

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