Pain is unpleasant sensory and emotional experience accompanied by tissue injury. Often an indi-vidual experience, it can be influenced by different physiological, psychological, and social factors. Fibromyalgia, one of the most difficult-to-treat types of pain, is characterized by general muscle pain accompanied by obesity, fatigue, sleep, and memory and psychological concerns. Fibromyal-gia has increased nociceptive sensations via central sensitization in the brain and spinal cord level. We used intermittent cold stress to create a mouse fibromyalgia pain model (Day 0: 3.69  0.14 g; Day 5: 2.13  0.12 g). Mechanical pain could be reversed by eicosapentaenoic acid (EPA) admin-istration (Day 0: 3.72  0.14 g; Day 5: 3.69  0.13 g). A similar trend could be also observed for thermal hyperalgesia. The levels of elements in the transient receptor potential V1 (TRPV1) sig-naling pathway were increased in the ascending pain pathway, including the thalamus, medial prefrontal cortex, somatosensory cortex, anterior cingulate cortex, and cerebellum. EPA intake significantly attenuated this overexpression. Novel chemogenetics method was used to indeed in-hibit SSC to ACC activity presented an analgesic effect through TRPV1 downstream pathway. The present results provide insights as to the role of TRPV1 signaling pathway as in fibromyalgia and its potential as a clinical target.

Neuropathic pain is initiated by a malfunction of the somatosensory cortex system. Acupuncture had been shown to have therapeutic effects for neuropathic pain, although with uncertain mechanisms. We used electroacupuncture (EA) to treat mice spared nerve injury (SNI) model and explore the underlying molecular mechanisms through novel chemogenetic techniques. Both me-chanical and thermal pain were found in SNI mice till four weeks (mechanical: 3.23 ± 0.29 g; thermal: 4.9 ± 0.14 s). Hyperalgesia was attenuated by 2 Hz EA (mechanical: 4.05 ± 0.19 g; ther-mal: 6.22 ± 0.26 s) but not with sham EA (mechanical: 3.13 ± 0.23 g; thermal: 4.58 ± 0.37 s), sug-gesting EA’s specificity. In addition, animals with transient receptor potential V1 (Trpv1) deletion showed no significant induction of neuropathic pain (mechanical: 4.43 ± 0.26 g; thermal: 6.24 ± 0.09 s). Moreover, we found increased levels of inflammatory factors such as interleukin-1 beta (IL1-β), IL-3, IL-6, IL-12, IL-17, tumor necrosis factor alpha, and interferon gamma after SNI modeling, which decreased in EA and Trpv1-/- group rather than sham group. Western blot and immunofluorescence analysis showed similar tendency in the dorsal root ganglion, spinal cord dorsal horn, somatosensory cortex (SSC), and anterior cingulate cortex (ACC). In addition, a novel chemogenetics method was used to precisely inhibit SSC to ACC activity showed an analgesic effect through TRPV1 pathway. In summary, our findings indicate a novel mechanism underlying neuropathic pain as beneficial targets for neuropathic pain.