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Maternal dietary carbohydrate restriction influences the developmental profile of postnatal rat brain indoleamine
K G Koski1, L Lanoue, S N Young
1School of Dietetics and Human Nutrition, Macdonald Campus of McGill University, Ste. Anne de Bellevue, Québec, Canada.
Dietary glucose restriction during pregnancy can retard fetal brain development, lower term brain glycogen levels and adversely affect the serotonergic neurotransmitter system in the fetus. To study if the postnatal profile of brain indoles continues to respond to these diet-induced changes, pregnant rats were fed graded levels (0, 12, 24, 60%) of glucose from impregnation to day 15 postpartum, and neonatal brain measurements were made. A steady decrease in tryptophan levels, a steady increase in 5-hydroxytryptamine (5-HT) levels and a U-shaped change in 5-hydroxyindoleacetic acid (5-HIAA) were observed during the first 15 postpartum days. Superimposed on these development profiles was a temporary surge in the concentrations of all three indoles 24 h after birth, which was dramatic for tryptophan and more modest for 5-HT and 5-HIAA. The level of carbohydrate in the maternal diet significantly influenced the magnitude of this increase in tryptophan, 5-HT and 5-HIAA at 24 h: the values were significantly higher in the carbohydrate-restricted (12 or 24%) rat pups when compared with control or carbohydrate-free (0% glucose) offspring. No effects of dietary treatment were apparent by day 6. However, the reemergence of a significant difference in brain 5-HT content at day 15 postpartum indicates that even when energy intake is adequate the level of carbohydrate in the maternal diet may continue to play a role in modulating serotonergic neurotransmitter levels later in development.
Dietary glucose restriction during pregnancy can retard fetal brain development, lower term brain glycogen levels and adversely affect the serotonergic neurotransmitter system in the fetus. To study if the postnatal profile of brain indoles continues to respond to these diet-induced changes, pregnant rats were fed graded levels (0, 12, 24, 60%) of glucose from impregnation to day 15 postpartum, and neonatal brain measurements were made. A steady decrease in tryptophan levels, a steady increase in 5-hydroxytryptamine (5-HT) levels and a U-shaped change in 5-hydroxyindoleacetic acid (5-HIAA) were observed during the first 15 postpartum days. Superimposed on these development profiles was a temporary surge in the concentrations of all three indoles 24 h after birth, which was dramatic for tryptophan and more modest for 5-HT and 5-HIAA. The level of carbohydrate in the maternal diet significantly influenced the magnitude of this increase in tryptophan, 5-HT and 5-HIAA at 24 h: the values were significantly higher in the carbohydrate-restricted (12 or 24%) rat pups when compared with control or carbohydrate-free (0% glucose) offspring. No effects of dietary treatment were apparent by day 6. However, the reemergence of a significant difference in brain 5-HT content at day 15 postpartum indicates that even when energy intake is adequate the level of carbohydrate in the maternal diet may continue to play a role in modulating serotonergic neurotransmitter levels later in development.