RAPID AXOPLASMIC TRANSPORT OF PROTEINS IN REGENERATING SENSORY NERVE FIBERS

Abstract— Utilizing an in vitro labeling procedure, the proteins carried by rapid axoplasmic transport in normal and regenerating sensory fibers of the rat sciatic nerve were compared. No statistically significant differences were found when the total amount of transported protein was compared in control and sectioned nerves at times from 2 to 76 days following axotomy. Fractionation of labeled proteins on polyacrylamide slab gels enabled the identification of some 25 individual transported proteins. By this criterion, no differences were detectable in the composition of proteins synthesized in the dorsal root ganglia from which sectioned vs control sciatic nerves project. When the electrophoretic distributions of transported proteins from control and sectioned nerves were compared, significant' differences were observed. The appearance and disappearance of two proteins were temporally related to chromatolytic changes in the nerve cell body. In addition, the composition of transported proteins in undamaged control nerves contralateral to the sectioned nerves exhibited changes which were not observed in either normal control nerves or sectioned nerves. Changes in the composition of transported proteins as a function of time following the onset of chromatolysis may be involved in controlling nerve regeneration in sensory nerve fibers.