Masses of phosphorylated neurofilaments are associated with abnormal Golgi apparatus of anterior horn neurons of β, β′-iminodipropionitrile-intoxicated rats

The Golgi apparatus (GA) of anterior horn neurons of rats chronically intoxicated with β,β′‐iminodipropionitrile (IDPN) in drinking water was examined with an organelle‐specific antibody. The neuropile of the anterior horns contained the typical axonal spheroids associated with IDPN toxicity while the perikarya of approximately one‐third of the neurons contained phosphorylated neurofilaments, which are not found in the perikarya of control rat neurons. By serial or double immunostaining with the SMI‐31 and anti‐MG 160 antibodies, there were no morphological changes of the GA in the majority of neurons including neurons with a mild to moderate degree of neurofilamentous accumulation. However, a few neurons with a massive accumulation of phosphorylated neurofilaments contained abnormal profiles of the GA which consisted of focal clustering, reduction in size and fragmentation. The results suggest that masses of phosphorylated neurofilaments are associated with struc‐tural abnormalities of the GA.