The fine structure of stratified ependyma in the ventricular wall of N-ethyl-N-nitrosourea-treated rats.

Ependymal stratifications, up to 15 cell layers in thickness at the floor of the lateral ventricle of rats treated transplacentally with N-ethyl-N-nitrosourea (ENU), are described. Ultrastructurally the constituent ependymal cells are well-differentiated and show no morphological signs of neoplasia. The possibility that these findings are due to the toxicity or carcinogenicity of ENU is discussed.