A quantitative study of retrograde axonal transport in motor and sensory neurons

We used 3H N-succinimidyl propionate to covalently label in vivo proteins of the rat sciatic nerve, and studied the accumulation of radioactively labeled proteins in the cell bodies of the ipsilateral dorsal root ganglion and ventral horn of spinal cord to assess retrograde axonal transport in sensory and motor neurons respectively. In each case the early accumulation of a small amount of radioactively labeled protein is followed by the later accumulation of a larger amount, which subsequently declines to lower levels. The differences between accumulation in the motor neuron and sensory neuron are discussed. Quantitative assessment of retrograde axonal transport will allow future determination of alterations in that transport after nerve injury and in toxic states, which will help elucidate the role of retrogradely transported proteins in neuronal cell biology.