Comparison of Electroacupuncture and Morphine-Mediated Analgesic Patterns in a Plantar Incision-Induced Pain Model

Figure 2

Intraperitoneal injections of naloxone (Nal) reversed EA analgesic effect on postincisional pain. (a) Summary of the protocols used in this experiment. Naloxone was injected at doses of 2 mg/kg immediately before anesthesia and 1 mg/kg immediately after PI and repeated the administration mode on D1 and D2. BL: baseline on one day before PI; D: postplantar incision day; EA: electroacupuncture; h: hour; i.p.: intraperitoneal injection; Nal: naloxone, marked with an arrow line; PI: plantar incision, marked with a solid triangle; pre: before daily Nal i.p. and EA treatment. (b) Intraperitoneal injections of naloxone almost completely antagonized EA analgesia to basal post-PI pain levels. Nal: group with i.p. naloxone, Saline+EA+PI: group for PI with repeated saline injections and EA treatments, Nal+Sham+PI: group for PI with repeated naloxone injections and sham needle insertion, and Nal+EA+PI: group for PI with repeated naloxone injections and EA treatments; ### < 0.001 groups versus Nal; & < 0.05 Nal+EA+PI versus Nal+Sham+PI; ∗ < 0.05, ∗∗ < 0.01, ∗∗∗ < 0.001 Saline+EA+PI versus Nal+EA+PI; one-way ANOVA with Tukey’s multiple comparison test; (Nal), 7 (Nal+Sham+PI), 7 (Nal+EA+PI), and 6 (Saline+EA+PI).

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