Exposure to triphenyl phosphite results in widespread degeneration in the mammalian central nervous system.

Previous studies in mammals have found that exposure to triphenyl phosphite results in cellular and axonal degeneration in the spinal cord and medulla. However, the nature of concomitant clinical signs suggested that other areas of the central nervous system might also be affected. In this study, the brains of ferrets receiving single subcutaneous injections of triphenyl phosphite were examined 8-12 days after dosing. Widespread areas of axonal, terminal, and somatic degeneration were seen in medullary, pontine, and thalamic nuclei. Extensive axonal and terminal degeneration were also noted in the cerebellar granule cell layer and in the cerebral cortical primary visual and sensorimotor areas. These data indicate that triphenyl phosphite exerts a potent neurotoxic effect, not only in the medulla and spinal cord, but also in the cerebellum, thalamus, and cerebral cortex.