Transport of proteins, glycoproteins and cholinergic enzymes in regenerating hypoglossal neurons

The accumulation of ³H]leucine- and ³H]fucose-labelled axonal proteins, acetyl-CoA : choline O-acetyltransferase (ChAc, EC 2.3.1.6) and acetylcholinesterase (AChE, EC 3.1.1.7) was studied proximal to a ligature applied to the hypoglossal nerve of the rabbit at different phases of nerve regeneration. After 1 week of regeneration, the accumulation of rapidly migrating ³H]leucine-labelled proteins, ChAc and AChE was reduced as compared to that of the contralateral nerve. In contrast, the accumulation of ³H]fucose-labelled glycoproteins was markedly increased. After a regeneration period of 4-6 weeks, the accumulation of proteins and glycoproteins in the regenerating nerve was increased whereas the accumulation of ChAc and AChE was almost normal. The results indicate an initial depression of the synthesis and axonal transport of the bulk of rapidly migrating proteins, ChAc and AChE in the chromatolytic hypoglossal neurons whereas the synthesis and transport of rapidly migrating glycoproteins is increased. These initial changes are less pronounced during the subsequent regeneration period.