Involvement of P2X7 receptors in satellite glial cells of dorsal root ganglia in the BmK I -induced pain model of rats.

The P2X7 receptor (P2X7R) plays an important role in inflammatory and neuropathic pain. Our recent study indicated that activation of P2X7R in microglial cells of spinal cord contributes to the inflammatory pain induced by BmK I, the major active compound from Buthus martensi Karsch (BmK). In the present study, we further investigated whether P2X7R in satellite glial cells (SGCs) of dorsal root ganglion (DRG) is involved in the BmK I-induced pain in rats. The results found that the expression of P2X7R in SGCs was increased in the ipsilateral side of IA-L5 DRGs after intraplantar injection of BmK I. Moreover, the expression of an inflammatory cytokine IL-1 beta was increased in DRG after BmK I injection. Systemic administration of an inhibitor of P2X7R (A-438079) significantly inhibited both spontaneous and evoked nociceptive behaviors induced by BmK I. These results suggest that the P2X7R in SGCs of DRG might contribute to pain induced by toxins that sensitize peripheral sensory nerves.