Ricin transport distinguishes between central and peripheral neurons.

Ricin conjugated to horseradish peroxidase was retrogradely transported by peripheral neurons of the nodose ganglion after microinjection into the nucleus tractus solitarius but was not transported by central neurons projecting to the nucleus tractus solitarius. Similarly, ricin was not transported by central neurons projecting to the caudate nucleus. Differences in labeling of central and peripheral neurons with ricin may reflect differences in surface glycoconjugates on processes of these neurons.