Figure 4

Spinal purinergic system involvement in analgesia induced by motor cortex stimulation (MCS). (A) Quantification of P2X4 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 means ± SEM (n = 5 images per animal, n = 3 to 5 animals per group). *P < 0.05 compared to the sham group. #P < 0.05 compared to the sham and CCI groups. Photomicrographs illustrating P2X4 immunofluorescence in the DHSC, ipsilateral to sham surgery or CCI, in sham (B), CCI (C), CCI + MCS (responsive) (D), and CCI + MCS (refractory) (E) animals. Scale bars: 130 μm.