[Effect of ethanol on the development and maturation of synapses in the rat hippocampus]

Rats of both sexes were exposed to ethanol during the entire period of the fetal life as well as the whole period of postnatal ages, and their brains were investigated at 2, 7, 14, 21, and 70 days postnatally. Control animals were examined at each age. Densities of synapses in the strata radiatum and lacunosum-moleculare of CA1 in the hippocampus were analyzed by quantitative ultrastructural techniques. Densities of all synapses in the strata radiatum and lacunosum-moleculare in ethanol-treated group were significantly lower than those of control group on 2, 14, 21 and 70 days. However, there were no significant differences in the ratio of axo-spinous to axo-shaftic synapses between control and ethanol-treated group. In addition, in regard to the rate of reduction in densities of all synapses, no change was detectable between both strata that receive different groups of afferent fibers. These data suggest that chronic administration of ethanol during the fetal and postnatal ages reduces the synaptic density in this area, and that this effect is neither specific to types of synapses nor to sorts of afferent fibers.