Fluoride related changes in behavioral outcomes may relate to increased serotonin

Fluoride ingestion has been linked to changes in behavior in mice and rats, related to dose, sex of the animal, and the timing of exposure. Previous studies have shown the behavior of female rats to be most affected by postnatal fluoride exposure, and in this study we determined the effects of postnatal fluoride exposure on anxiety related behavior and serotonin. Mice given 50 ppm fluoride in drinking water had increased entries in the open arms of the elevated plus maze, suggesting reduced anxiety. Both peripheral and central serotonin was increased in the fluoride treated mice. In a cohort of children drinking water containing 2.5 ppm fluoride, serum serotonin was also increased as compared to controls. The mechanisms by which fluoride results in an increase peripheral and central serotonin are not well understood, but warrant further study, as these effects may also be relevant to prenatal fluoride related changes in behavior in both mice and humans.