Development of the Nervous System
Fetal Alcohol Spectrum Disorder (FASD) is caused by maternal ingestion of alcoholic beverages during pregnancy that results in fetal insult. Cognitive symptoms of FASD include autism, mental retardation, epilepsy, and attention deficit hyperactivity disorder. Zebrafish (Danio rerio) is an excellent model organism to study neurodevelopmental ramifications of FASD for the following reasons: First, zebrafish embryos are optically clear, allowing visualization of neuronal pathways with single-cell resolution. Second, evolutionarily conserved gene pathways and mechanisms, together with neuroanatomical conservation combine in this vertebrate model system to allow direct correlations to humans. Third, zebrafish exposed to high doses of ethanol during embryogenesis develop physical deformities identical to those found in humans with FASD, including facial deformities. In order to understand neuronal responses to ethanol exposure during development, we are examining axon pathfinding in zebrafish embryos that are continuously exposed to ethanol. Our preliminary data demonstrates that low levels of EtOH exposure result in specific axon guidance defects in numerous neuronal subtypes in the spinal cord.