Retrograde axon reaction following section of asynaptic nerve fibers.

The asynaptic spinal neurons of the gymnotid teleost Sternarchus albifrons show several distinct characteristics of the retrograde reaction of the perikaryon (which corresponds to chromatolysis in mammals) following axotomy. Nuclei of affected cells are characteristically eccentric. Large bundles of neurofilaments, never seen in normal perikarya of these cells, become prominent following axotomy. There is a marked increase in the number and size of dense bodies in the affected perikarya. Large arrays of parallel rough endoplasmic reticulum, never seen in normal cells, are frequent in the axotomized neurons. These results demonstrate that disconnection from synaptic terminals is not a necessary condition for the retrograde reaction of the perikaryon following axotomy.