Effects of in utero ethanol exposure on serotonin uptake in cortical regions

Previously, this laboratory found that the 19- and 35- to 37-day-old offspring of rats that consumed ethanol on a chronic basis prior to parturition had a decreased cortical content of serotonin (5-HT) and 5-hydroxyindoleacetic acid (5-HIAA) as well as a decreased number of cortical 5-HT1 binding sites. These results emphasized the sensitivity of the developing cortical serotonergic nerves to the effects of in utero ethanol exposure. In the present study, we examined the effects of in utero ethanol exposure on an additional component of the developing cortical serotonergic systems. Specifically, we examined the uptake of [3H]-5-HT by synaptosomes which were isolated from the motor or somatosensory regions of the cerebral cortex. The results demonstrated that the Vmax for serotonin uptake was significantly decreased (p less than 0.025) by approximately 15-20% in the motor cortices of the 19- and 35-day-old offspring of rats that consumed ethanol on a chronic basis prior to parturition. In addition, there was a significantly (p less than 0.025) approximately 30% decrease in the Km for serotonin uptake in the motor cortex of 35-day-old offspring of ethanol-fed rats. In contrast, neither the (Km) nor the Vmax for serotonin uptake were significantly altered (p greater than 0.05) in the somatosensory cortices in 19- or 35-day-old offspring of ethanol-fed rats. These results emphasize the selective sensitivity of developing cortical projections of the serotonergic system.