ABSTRACT
This chapter the neuronal changes that occur at each stage of the successful regenerative sequence, with particular emphasis on the role of retrograde axonal transport in conveying to the cell body information about the status of the axon. Axon injury initiates a host of metabolic and structural changes in the neuron, its surrounding glial cells and the synapses of other neurons upon it. Target-disconnection signals are negative and occur when the cell body is deprived of a target-derived trophic factor which is retrograde-transported to the cell body and maintains normal metabolism. Axon sprouting can begin very rapidly, within a few minutes in vitro, and from both ends of the severed axon, suggesting that initial sprouting can occur without changes in cell body protein synthesis, but induced by purely local events at the site of injury. Retrograde transport of endogenous protein in the injured nerve also undergoes changes as the axon elongates.
