Fucosylated glycans in the periventricular structures and the cerebrospinal fluid of the fetal rat forebrain.: An autoradiographic and lectin binding histiotopic study

Our autoradiographic H-3-fucose incorporation study of the brains of 20-day-old rat fetuses showed that the synthesis of fucosylated glycans is significantly higher in the ventricular germinative zone of the forebrain hemisphere than in the more superficial layers, including the cortical plate. Intense incorporation of H-3-fucose also occurred in the choroid plexus, both its epithelial and stromal component. in the primordial ependymal lining of the lateral ventricles, meninges and capillaries of the forebrain parenchyma. In the lateral ventricles, densely labeled microprecipitates of the cerebrospinal fluid (CSF) were occasionally observed. The histiotopic differences in H-3-fucose labeling were absent, or were much less expressed, in the autoradiograms prepared from unfixed cryostat sections containing mainly unincorporated isotope. This indicates that the blood-mediated supply of H-3-fucose to the studied brain compartments was essentially equal and our incorporation data reflect actual differences in the rate of fucosylation within the forebrain hemispheres. The cytochemical lectin-binding assay, carried out with Ulex europaeus and Lotus tetragonolobus agglutinins, showed that regions with a higher rate of H-3-fucose incorporation were also richer in fucose-bearing glycoconjugates. The study revealed that the periventricular regions and the CSF of fetal rat forebrain form a fucosylated glycan-enriched complex, which represents a new chemoarchitectonic feature that may be of importance for maintaining the germinative properties of the ventricular neuroepithelium and the growth of the hemispheric ventricles. (C) 2001 ISDN. Published by Elsevier Science Ltd. All rights reserved.