Cerebellar histogenesis and synaptic maturation following pre- and postnatal alcohol administration. An electron-microscopic investigation of the rat cerebellar cortex.

Fetal alcohol syndrome was produced in rats by feeding an ethanol-enriched, vitamine -supplemented liquid diet over a period of 4 weeks before mating and throughout pregnancy. The amount of ethanol was equivalent to 38-40% of the daily calories; control animals were fed an isocaloric amount of sucrose. The offspring of experimental animals displayed a diminished birth weight. In contrast to previous experiments, the ethanol diet was also administered during the lactating period. On postnatal day 7, experimental animals and controls were killed by perfusion and the cerebella prepared for electron microscopy. Morphometric analysis showed a reduced number of Purkinje cells. On day 12, Purkinje cells of experimental animals displayed ultrastructurally fewer organelles. Furthermore, a delayed synaptogenesis in the molecular layer was demonstrated with osmium-zinc iodide and ethanolic phosphotungstic acid showing an immature appearance of the presynaptic grid and weaker stained synaptic cleft material. The following discussion deals with possible mechanisms underlying these alcohol-induced alterations of cerebellar synaptogenesis.