Figure 1

Antagonism of P2X3 receptors on discogenic pain behavior. (A) In rats treated with NP, the mechanical paw withdrawal threshold (PWT) was decreased significantly on the ipsilateral side at 3, 7, 14, 21 and 28 days after surgery compared to the sham group (*P < 0.05, n = 11 for the LDH group and n = 8 for the sham group). (B) In rats treated with NP, the body weight bearing difference was dramatically increased between hindlimbs at 3, 7, 14, 21 and 28 days after surgery compared to the sham group (*P < 0.05, n = 7 for the LDH group and n = 6 for the sham group). (C) Compared to the sham group, NP-application did not produce any effect on time to fall for rats on the Rota rod (n = 8 for each group, P > 0.05). (D) Administration of the P2X3R inhibitor A317491 mitigated mechanical hyperalgesia in LDH rats. The A317491-induced antinociceptive effects were observed at 30 min and disappeared 4 hours after a single intrathecal (it) injection of A317491 at the doses of 30,100 and 300 nmol. n = 6 rats for each group, *P < 0.05, **P < 0.01 compared to the NS group. (E) Administration of the P2X3R inhibitor A317491 reduced the body weight bearing difference induced by LDH. The A317491-induced antinociceptive effect disappeared 4 hours after a single intrathecal (it) injection of A317491 at doses of 30,100 and 300 nmol; n = 6 rats for each group *P < 0.05, compared to Pre injection values. (F) Administration of A317491 (it) did not produce any effect on PWT in healthy control rats (n = 5, P > 0.05). (G) Administration of A317491 (it) did not produce any effect on the time to fall for LDH rats in the Rota rod test (n = 8).