CONICET | Buscador de Institutos y Recursos Humanos

Previously, we have demonstrated alterations in the neuronal cytoskeleton in cerebral cortex of ratsprenatally exposed to ethanol. We also showed in rat primary cortical neurons that ethanol inducedneuronal death and a decrease in the elongation and branching of dendrites.The aim of the present work was to evaluate the ultrastructural changes in rat cortical neuronsexposed to 50mM ethanol during 24 hours.Cortical neurons were obtained from one-day-old Wistar rats. Cells were plated at 3.5 x 106 cells/35 mm dish and grown in Neurobasal supplemented with B-27 and 2 mM L-glutamine until complete differentiation. 12 h before treatment, cells were B-27 deprived, and exposed to 50 mM ethanol during 24 h. After that, cells were fixed with 2 % glutaraldehyde + 1% formaldehyde in 0,1M cacodylate buffer for 60 min. After washing in this buffer, cells were postfixed in 2 % OsO4 containing 1 % potassium ferrocyanide for 60 min., treated with 0.1 % tannic acid for 1 min, washed and stained in block with 2 % aqueous uranyl acetate for 120 min , and embedded in Eppon 812 Ultrathin sections were photographied in a Zeiss electron microscopy at 30000X and 50000X.Primary cortical neurons exposed to ethanol showed indented nucleus, increased number of lipidicvacuoles, lisosomes and multilamellar vesicles, dilated endoplasmatic reticulum lumen and adisorganized Golgi apparatus with a ring-shape appearance.Heterogeneous distribution with a decreased density of microtubules (MT) in neurites was alsoobserved in cortical neurons exposed to ethanol (control: 139.2 ± 32.52 vs. treated: 105.5 ± 31.56 MT/μm2).The ultrastructural changes observed in primary neurons exposed to ethanol may explain some of the neuronal dysfunctions observed ?in vivo?. Cytoskeleton disorganization may be result in a dendritic processes decrease. The alterations in the Golgi apparatus structure, commonly observed in autophagic process, and the increased lipidic vesicles are some of the most important featuresrelated with the cellular toxicity by ethanol exposition.