Ultrastructure of the neural basal lamina in loop-tail mice

Ultrastructural features of the neural basal lamina were studied by means of the tannic acid and ruthenium red techniques in normal and abnormal dysraphic loop-tail mice at 9-11 days of gestation. With ruthenium red, the configuration of the neural basal lamina is similar in both normal and abnormal embryos at 9-11 days. However, differences were detected in the abnormal 9-day embryos processed with tannic acid, as compared with normal littermates. These include irregularities in the lamina rara externa, as well as differences in the staining pattern of the neuroepithelial cell plasma membrane. By 11 days of gestation, the lamina rara externa of the normal embryos shows features similar to those observed in the 9-day abnormal embryos.