Huperzine A Alleviates Mechanical Allodynia but Not Spontaneous Pain via Muscarinic Acetylcholine Receptors in Mice

Figure 1

Systemic injection of Hup A raised the PWT in nerve-injured mice. (a) Hup A at 0.02 mg/kg had no effect on the PWTs in the sham and nerve-injury groups (two-way repeated measures ANOVA, sham versus injury: , ; treatments: , , per group, under Tukey’s test). (b) Hup A at 0.075 mg/kg had no effect on the PWTs in the sham and nerve-injury groups (two-way repeated measures ANOVA, sham versus injury: , ; treatments: , , for sham, for CPN, under Tukey’s test). (c) Hup A at 0.1 mg/kg increased the PWTs in the nerve-injury group, but not in the sham group, and this effect was blocked by atropine (two-way RM ANOVA, sham versus injury: , ; treatments: , , per group, under Tukey’s test). (d) Hup A at 0.15 mg/kg raised the PWTs in the nerve-injury group, but not in the sham group (two-way RM ANOVA, sham versus injury: , ; treatments: , , per group, under Tukey’s test). (e) Increasing the dose of Hup A to 0.2 mg/kg raised the PWTs in both groups, and the analgesic effects lasted >2 h (two-way RM ANOVA, sham versus injury: , ; treatments: , , per group, under SNK test). (f) Hup A at 0.1 mg/kg increased the PWTs in the CFA injection group, but not in the saline group, and this effect was blocked by atropine (two-way RM ANOVA, saline versus CFA: , ; treatments: , , saline, ; CFA, , ; under Tukey’s test). “Baseline” indicates the PWTs before operation. “Before” indicates PWTs before intraperitoneal drug injection.

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