Cerebellar degeneration in the rat following rapid correction of hyponatremia.

Degenerative lesions in the superior vermis of the cerebellum were produced in 8 of 14 rats that were first made hyponatremic for three days with vasopressin and water and then given hypertonic saline. Within the superior vermis, lesions were predominantly localized to the crests of the folia. These lesions were characterized by demyelination of folial white matter and necrosis of granule cells at the junction with the white matter. In severe degeneration, the entire width of the granule cell layer was involved and Purkinje cell necrosis was found as well. Hyponatremia alone or administration of hypertonic saline to normonatremic rats did not result in lesions. Because of the topographical and histopathological similarity of these lesions to those of alcoholic cerebellar degeneration, our findings raise the possibility of a contribution of electrolyte-induced injury to the pathogenesis of alcoholic cerebellar degeneration.