Involvement of basolateral amygdala-rostral anterior cingulate cortex in mechanical allodynia and anxiety-like behaviors and potential mechanisms of electroacupuncture

Aims

Chronic pain is highly associated with anxiety. Electroacupuncture (EA) is effective in relieving pain and anxiety. Currently, little is known about the neural mechanisms underlying the comorbidity of chronic pain and anxiety and the EA mechanism. This study investigated a potential neural circuit underlying the comorbid and EA mechanisms.

Methods

Spared nerve injury (SNI) surgery established the chronic neuropathic pain mouse model. The neural circuit was activated or inhibited using the chemogenetic method to explore the relationship between the neural circuit and mechanical allodynia and anxiety-like behaviors. EA combined with the chemogenetic method was used to explore whether the effects of EA were related to this neural circuit.

Results

EA attenuated mechanical allodynia and anxiety-like behaviors in SNI mice, which may be associated with the activity of CaMKII neurons in the basolateral amygdala (BLA). Inhibition of BLA^CaMKII-rACC induced mechanical allodynia and anxiety-like behaviors in sham mice. Activation of the BLA^CaMKII-rACC alleviated neuropathic pain and anxiety-like behaviors in SNI mice. The analgesic and anxiolytic effects of 2 Hz EA were antagonized by the inhibition of the BLA^CaMKII-rACC.

Conclusion

BLA^CaMKII-rACC mediates mechanical allodynia and anxiety-like behaviors. The analgesic and anxiolytic effects of 2 Hz EA may be associated with the BLA^CaMKII-rACC.