Developmental changes in serotonergic neurons by maternal ethanol consumption in the rat offspring

The brain levels of 5-hydroxytryptamine (5-HT) and 5-hydroxyindoleacetic acid (5-HIAA), the synthesis rate of 5-HT and 5-HIAA, and the elimination rate of 5-HIAA in the rat offspring brain exposed to ethanol were examined. Ethanol was administered as a drinking water (group L) and in combination with 4 g/kg. p.o. of ethanol (group H) to the pregnant mothers during days 3 to 21 of gestation. There was no difference in brain 5-HT levels between control and groups L and H at 2, 3, 4 and 6-7 weeks of age. A significant decrease in brain 5-HIAA levels was observed at 3 and 6-7 weeks of age in group L and group H, respectively. In the pups of group H, the 5-HT synthesis rate and the elimination rate of 5-HIAA reduced at 4 and 6-7 weeks of age in comparison with the respective control pups. On the other hand, in the pups of group L, the 5-HT synthesis rate increased, and the 5-HIAA synthesis rate reduced at 3, 4 and 6-7 weeks of age. These results suggest that differential exposure to ethanol, such as group L and H, in the CNS during developmental period induces a differential change in the activity of serotonergic system.