The mechanisms which regulate the regeneration of dorsal root ganglia (DRG) sensory neurons following injury remain poorly understood. Damage to a peripheral nerve causes major changes within the cell bodies of the DRG neurons which are thought to promote regeneration, by stimulating neurite outgrowth, and enhance survival of the damaged neurons. Within the intact adult DRG the neuropeptide galanin is expressed at low levels in less than 5% of neurons. However, following peripheral nerve injury there is a rapid and robust upregulation of both galanin mRNA and peptide leading to approximately 50% of all DRG neurons expressing the peptide. Previous work from our laboratory has shown that galanin plays an important role in both neuronal survival and regeneration (1,2,3). In this study we used a proteomic approach to compare protein expression within the DRG of wildtype and galanin knockout mice, both after acute isolation and following an in vitro model of axotomy. Adult mice were killed humanely and their DRGs removed. For acutely isolated samples, DRGs were collected on ice and homogenised. As an in vitro model of nerve injury DRGs were cultured as free floating explants for a period of 3 days (3DIV) (4). DRG extracts were analysed by two-dimensional gel electrophoresis. Differences in protein expression were compared between (a) acutely isolated wildtype and acutely isolated galanin knockout DRG, (b) post-injured (3DIV) DRG from wildtype and galanin knockout mice and (c)acutely isolated and post-injured wildtype DRG. Following tryptic digestion and mass spectrometric analysis several differentially expressed proteins have been identified. These include proteins involved in cytoskeletal reorganisation, metabolism and ubiquitination.