The axonal pathology in chronic IDPN intoxication.

Neurofilamentous axonal swellings occur in a number of degenerative and toxic disorders of the nervous system. In one of these, experimental intoxication with beta, beta'-iminodiproprionitrile (IDPN), accumulation of neurofilaments has been shown to result from a defect in slow axonal transport. The consequence of this functional abnormality is a series of changes in axonal morphology: Neurofilaments accumulate in the proximal axon; the proximal axon becomes swollen; the distal axon loses volume (axonal atrophy). These studies indicate that axonal atrophy occurs secondary to an impairment of slow axonal transport and suggest that a similar abnormality may underlie the pathological changes in certain other degenerative and toxic diseases of the nervous system.