Retrograde transport of horseradish peroxidase in transected axons. II. Relations between rate of transfer from the site of injury to the perikaryon and onset of chromatolysis.

The sciatic nerves of 2--3 month-old mice, rats and rabbits were crushed and at the same time horseradish peroxidase (HRP) was applied around the crushed region at mid-thigh level. At varying time intervals thereafter, HRP was seen in neurons of the corresponding spinal ganglia and levels of the spinal cord. The rate of ascent of HRP appeared to be similar in the different animals and to be independent of the length of the nerve. The accumulation of HRP was more conspicuous in small than large neurons in the ganglia at early stages after the nerve crush. The arrival of HRP in the perikarya preceded the onset of early morphological changes in the neurons (chromatolysis). The rate of ascent of the signal for chromatolysis appeared to be within the same range as that of the retrograde transport of HRP in the crushed axons. The possibility therefore exists that these two phenomena are in some way interrelated.