Chronic pain, such as
neuropathic pain, causes anxiety and other negative emotions, which aggravates the
pain sensation and increases the risk of
chronic pain over time.
Dopamine receptor D1 (DRD1) and
dopamine receptor D2 (DRD2) in the basolateral amygdala (BLA) have been implicated in mediating anxiety-related behaviors, but their potential roles in the BLA in
neuropathic pain-induced anxiety have not been examined.
Electroacupuncture (EA) is commonly used to treat
chronic pain and emotional disorders, but it is still unclear whether EA plays a role in
analgesia and anxiety relief through DRD1 and DRD2 in the BLA. Here, we used western blotting to examine the expression of DRD1 and DRD2 and pharmacological regulation combined with behavioral testing to detect anxiety-like behaviors. We observed that injection of the DRD1 antagonist
SCH23390 or the DRD2 agonist
quinpirole into the BLA contributed to anxiety-like behaviors in naive mice. EA also activated DRD1 or inhibited DRD2 in the BLA to alleviate anxiety-like behaviors. To further demonstrate the role of DRD1 and DRD2 in the BLA in spared nerve injury (SNI) model-induced anxiety-like behaviors, we injected the DRD1 agonist
SKF38393 or the DRD2 antagonist
sulpiride into the BLA. We found that both activation of DRD1 and inhibition of DRD2 could alleviate SNI-induced anxiety-like behaviors, and EA had a similar effect of alleviating anxiety. Additionally, neither DRD1 nor DRD2 in the BLA affected SNI-induced
mechanical allodynia, but EA did. Overall, our work provides new insights into the mechanisms of
neuropathic pain-induced anxiety and a possible explanation for the effect of EA treatment on anxiety caused by
chronic pain.