title: Ethanol Toxicity During Brain Development: Alterations of Excitatory Synaptic Transmission in Immature Organotypic Hippocampal Slice Cultures.
abstract: BACKGROUND
  The developing brain is particularly vulnerable to alcohol: Drinking during pregnancy can lead to a number of physical, learning, and behavioral disorders in the newborn. It has been demonstrated that immature and mature brain tissues display a differential sensitivity to ethanol (EtOH) toxicity and that cerebral structure and function are diversely impaired according to the stage of synaptic maturation.
  
  
  METHODS
  Rat organotypic hippocampal slice cultures were exposed for 7 days to EtOH (100 to 300 mM) after 2 days (immature) or 10 days (mature) of culture in vitro; EtOH was then removed from the medium, and 24 hours later, slices were analyzed by fluorescence microscopy, Western blotting, electrophysiology, and electron microscopy to explore the molecular mechanisms of EtOH toxicity in the developing hippocampus.
  
  
  RESULTS
  EtOH withdrawal elicited a selective CA1 pyramidal cell injury in mature slices, but not in immature slices. A significant increase in the expression of pre- and postsynaptic proteins in mature slices revealed that slice maturation is presumably associated with the development of new synapses. Incubation with chronic EtOH for 7 days and its removal from the medium induced a significant decrease in GluA1 and GluA2 expression levels; a significant reduction in the expression of synaptophysin and GluN2A was observed only after EtOH withdrawal. Whole-cell patch-clamp recordings showed that incubation with EtOH for 7 days induced a significant decrease in spontaneous excitatory postsynaptic current (sEPSC) frequency in CA1 pyramidal cells of immature slices and a trend toward a decrease in sEPSC amplitude. Electron microscopy revealed a disorganization of neurotubuli in immature slices after chronic exposure to EtOH.
  
  
  CONCLUSIONS
  These results indicate that prolonged incubation with EtOH and its subsequent withdrawal from the medium induce an impairment of excitatory synaptic transmission and possibly an incorrect formation of neuronal circuits in developing hippocampus in vitro, which is suggestive of mechanisms that may lead to mental retardation in fetal alcohol spectrum disorders.
authors.affiliation: Department of Health Sciences, Section of Clinical Pharmacology and Oncology, University of Florence, Florence, Italy.
authors.forename: Elisabetta
authors.initials: E
authors.lastname: Gerace
authors.affiliation: Department of Health Sciences, Section of Clinical Pharmacology and Oncology, University of Florence, Florence, Italy.
authors.forename: Elisa
authors.initials: E
authors.lastname: Landucci
authors.affiliation: Department of Health Sciences, Section of Clinical Pharmacology and Oncology, University of Florence, Florence, Italy.
authors.forename: Arianna
authors.initials: A
authors.lastname: Totti
authors.affiliation: Department of Experimental & Clinical Medicine, Section of Anatomy & Histology, Research Unit of Histology & Embryology, University of Florence, Florence, Italy.
authors.forename: Daniele
authors.initials: D
authors.lastname: Bani
authors.affiliation: Department of Experimental & Clinical Medicine, Section of Anatomy & Histology, Research Unit of Histology & Embryology, University of Florence, Florence, Italy.
authors.forename: Daniele
authors.initials: D
authors.lastname: Guasti
authors.affiliation: Clinical Toxicology Laboratory, Local Health Service, Florence, Italy.
authors.forename: Roberto
authors.initials: R
authors.lastname: Baronti
authors.affiliation: Department of Neuroscience, Psychology, Drug Research and Child Health (NeuroFarBa), Section of Pharmacology and Toxicology, University of Florence, Florence, Italy.
authors.forename: Flavio
authors.initials: F
authors.lastname: Moroni
authors.affiliation: Department of Neuroscience, Psychology, Drug Research and Child Health (NeuroFarBa), Section of Pharmacology and Toxicology, University of Florence, Florence, Italy.
authors.forename: Guido
authors.initials: G
authors.lastname: Mannaioni
authors.affiliation: Department of Health Sciences, Section of Clinical Pharmacology and Oncology, University of Florence, Florence, Italy.
authors.forename: Domenico E
authors.initials: DE
authors.lastname: Pellegrini-Giampietro
mesh_terms: D000428:Alcohol Drinking / Q000009:adverse effects; D000818:Animals; D000831:Animals, Newborn; D000431:Ethanol / Q000633:toxicity*; D006624:Hippocampus / Q000187:drug effects* / Q000254:growth & development* / Q000648:ultrastructure; D009924:Organ Culture Techniques; D051381:Rats; D017208:Rats, Wistar; D009435:Synaptic Transmission / Q000187:drug effects* / Q000502:physiology
chemical_list: D000431:Ethanol
keywords: Ethanol; Fetal Alcohol Spectrum Disorders; Glutamate Receptors; Neurotubuli; Organotypic Hippocampal Slices