Botulinum toxin C3 inhibits hyperalgesia in mice with partial sciatic nerve injury.

Mice with partial ligation of the sciatic nerve exhibited marked increase in the second phase nociceptive biting and licking behavior following intraplantar injection of formalin. The intrathecal pretreatment with botulinum toxin C3 dose-dependently attenuated the hyperalgesia in the second phase. These results suggest that a small G protein, Rho, and its downstream mechanisms are involved in the hyperalgesia following partial nerve injury.