Peripheral nerve injuries result in loss of neural control in denervated segments of the body, and severe disabilities for the patients. Nerve regeneration usually does not allow for adequate target reinnervation and functional restitution. Neuronal response and axonal regeneration imply a complex interaction of cell types and changes in the expression of many molecules. Many experimental models have been used to gain knowledge on nerve regeneration and to develop strategies to promote recovery. © 2004 Elsevier Ltd. All rights reserved.