Retrograde axonal transport of lead in rat sciatic nerve

A wavelike pattern of retrograde axonal transport of lead was demonstrated in rat sciatic nerve after injection of 203Pb into the triceps surae muscle. The transport rate was about 10 mm per day, and the lead reached the spinal cord by 9 days after injection. The distribution of lead within the spinal cord indicated the possibility of retrograde axonal transport in the upper and lower motor neurons, which might explain how lead enters the central nervous system and could be related to the postulated role of lead in causing amyotrophic lateral sclerosis. Lead may be useful in investigating retrograde transport experimentally.