Figure 3

Spinal cannabinoid receptor type 2 (CB2) and μ-opioid receptor (MOR) staining and its correlation with the effectiveness of motor cortical stimulation (MCS). Quantification of CB2 (A) and MOR (F) immufluorescence-staining in the dorsal horn of the spinal cord (DHSC), ipsilateral to sham surgery or chronic constriction injury (CCI), in sham-operated rats (Sham), CCI rats with neuropathic pain (CCI), CCI rats in which MCS reversed the neuropathic pain (CCI + MCS, responsive), and CCI rats unresponsive to MCS (CCI + MCS, refractory). Values represent the mean ± SEM (n = 5 images per animal, n = 3 to 5 animals per group). *P < 0.05 compared to the sham group. Photomicrographs illustrating CB2 (B-E) and MOR (G-J) immunofluorescence in the DHSC, ipsilateral to sham surgery or CCI, in sham (B, G), CCI (C, H), CCI + MCS (responsive) ( D, I ), and CCI + MCS (refractory) (E, J) animals. Scale bars: 130 μm.