Heterogeneous visceral nerve changes in acrylamide intoxication.

A variety of visceral nerves were studied by intermediate filament immunocytochemistry in rats intoxicated with acrylamide. Oesophageal and diaphragmatic motor end-plates were invaded and deformed by NF protein-like material, while afferent fibres of diaphragmatic neuromuscular spindles and myelinated sensory fibres of the iris showed striking terminal accumulation of similar material. The rich population of thin afferent fibres of the iris did not show abnormality, while pre-terminal changes were seen along the extrinsic fibres supplying the cornea and myenteric ganglia. Multiple lesions occurred in gut nerves, while scattered "enteric glial cells" were abnormally coarse and showed sharp increase of GFAP immunoreactivity. A distinct, delicately varicose appearence was revealed by NF protein immunostaining in bladder nerve fibers of normal rats, which was changed to one of coarse dilations by acrylamide. Apparently selective changes were found along different types of axons, indicating marked heterogeneity in cytoskeletal organization among visceral nerves. A non-uniform distribution of neurofilament degradation sites along distal regions of different axons is therefore suggested