Labelled Proteins in Rabbit Vagus Nerve Between the Fast and Slow Phases of Axonal Transport

Abstract —The profile of axonally transported [ 3 H]leucine‐labelled proteins in motor fibres of rabbit cervical vagus nerve was studied at time intervals after the appearance of fast‐phase and before the slow‐phase proteins, viz. 16 h after labelling of the cell bodies. No moving peak of radioactivity was seen. The transport blocking agents colchicine and vinblastine in vitro showed no difference in the mechanisms of anterograde transport between fast‐phase and later‐phase proteins, but differed in their effects on the retrograde flow. Double‐ligature experiments in vitro indicated the presence of rapidly‐migrating labelled proteins in cervical vagus up to 23.5 h after labelling and demonstrated the retrograde redistribution of proteins from nerve terminals and from a ligature. There was no evidence for an intermediate rate of protein transport.