Movement of horseradish peroxidase after its entry into intact and damaged peripheral nerve axons.

After application of a solution of horseradish peroxidase (HRP) around intact sciatic nerve axons in the rat, numerous HRP-labeled neurons were found in the ipsilateral L5 dorsal root ganglion and spinal cord ventral horn. These findings indicate that HRP enters intact peripheral nerve axons, and is transported retrogradely from its site of entry to their cell bodies of origin.