Increases in protein kinase C gamma immunoreactivity in the spinal cord dorsal horn of rats with painful mononeuropathy.

Eight days after chronic constrictive sciatic nerve injury (CCI), protein kinase C gamma (PKC gamma) immunoreactivity reliably increased in the spinal cord dorsal horn of CCI rats with demonstrable thermal hyperalgesia as compared to sham-operated controls. Such PKC gamma immunostaining was observed primarily in neuronal somata (ipsilateral > contralateral, laminae I-II > III-IV), indicating postsynaptic sites of PKC gamma increases. Both the development of thermal hyperalgesia and the increase in PKC gamma immunoreactivity in CCI rats were prevented by once daily intrathecal administration with 10 nmol MK-801 for 7 days. The present results provide further evidence for a role of PKC in N-methyl-D-aspartate (NMDA) receptor-mediated mechanisms of thermal hyperalgesia.