Objective To study the localizations and changes of mRNA for nNOSinteracting DHHC domaincontaining protein with dendritic mRNA (NIDD) in normal and injured peripheral nerves. Methods Realtime fluorescence quantitative PCR (FQPCR) and a combination of in situ hybridization and indirect immunofluorescence were used to detect the localizations and changes of mRNA for nNOS and NIDD. Results It was found that nNOS and NIDD were mainly localized in Schwann cells (SCs) of normal sciatic nerve, and the expression peaked in crushed sections of sciatic nerve in the 2nd week after injury and in proximate or distal transected stumps in the 1st week after injury respectively. Expressions of mRNA for nNOS and NIDD were detected in the perinuclear plasm of primary SCs as well. Conclusion The increase in mRNA for NIDD in SCs may