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

Figure 4

Infusion of Hup A into the anterior cingulate cortex did not alleviate spontaneous neuropathic pain. (a) The expression levels of AChE in the ACC were increased by the nerve injury (one-way ANOVA, , ; per group, under SNK test). (b) The AChE activity in the ACC of mice with nerve injury was increased, and this was inhibited by Hup A at 0.1 mg/kg, i.p. (one-way ANOVA, , ; for sham group, for injury, for 0.5 h group and 2 h group, under SNK test). (c) An example showing the injection site in the ACC of hematoxylin and eosin stained brain section. (d) Infusion of Hup A into the ACC increased PWTs in the sham and nerve-injury groups, and atropine blocked this analgesic effect (two-way RM ANOVA, sham versus injury: , ; treatments: , , per group, under Tukey’s test). (e) Time spent in the chambers during the preconditioning period of the CPP test (two-way RM ANOVA, sham versus injury: , ; saline versus drug: , , per group). (f) Infusion of Hup A into the ACC did not induce a preference for the drug-paired chamber in the CPP test (two-way RM ANOVA, sham versus injury: , ; saline versus drug: , , per group). (g) No change occurred in the preference time induced by Hup A in the CPP (t-test, ).

(a)

(b)

(c)

(d)

(e)

(f)

(g)