Effect of colchicine on the transport of axonal protein in the retinal ganglion cells of the rat

Abstract

The axonal transport of proteins in retinal ganglion cells of the adult rat was studied after intraocular injection of [ 3H]leucine. The precursor was incorporated into proteins that were subsequently transported along the axons of the retinal ganglion cells. This intraaxonal transport occurred at at least two different velocities: one rapid (120–140 mm/day) and one slow (2 mm/day). The specific radioactivity of the slow component of axonal flow was about five times greater than that of the fast component. The transported proteins reached the nerve terminals in the superior colliculus and the lateral geniculate body; about twice as much of the radioactivity appeared in the former as in the latter terminal region. Intraocularly injected colchicine had profound effects on axonal transport. A dose of 0·2 μg colchicine or more caused almost complete inhibition of the rapid phase, whereas a small fraction of the slowly migrating proteins was still transported to the terminals.