Reduced hyperalgesia induced by nerve injury, but not by inflammation in mice lacking protein kinase Cγ isoform

Abstract

Protein kinase C is one of protein kinases which might be involved in the nerve injury- or inflammation-induced hyperalgesia. The present study was designed to investigate the hyperalgesia with thermal paw-withdrawal test induced by sciatic nerve ligation or by intraplantar injection of a complete Freund's adjuvant solution in protein kinase Cγ knockout and its wild-type mice. Either sciatic nerve ligation or intraplantar injection of a complete Freund's adjuvant caused a marked decrease of the paw-withdrawal latency only on the ipsilateral, but not on the contralateral side of the paw in wild-type mice. This ipsilateral hyperalgesia induced by sciatic nerve ligation was significantly attenuated in protein kinase Cγ knockout mice. On the other hand, the ipsilateral hyperalgesia induced by complete Freund's adjuvant remained about the same in protein kinase Cγ knockout mice as in wild-type mice. The results indicate that protein kinase Cγ is involved in the development of the thermal hyperalgesia induced by nerve ligation, but not by complete Freund's adjuvant-induced inflammation.