Fluoride Action Network


To investigate whether excitotoxicity is involved in neurotoxicity of fluoride (F) alone and in combination with lead (Pb), the expression levels of the gene and protein N-methyl-D-aspartate receptor 1 (NMDAR1) in the hippocampus of offspring rat pups at postnatal days 14 and 28 exposed to F and/or Pb were determined by quantitative real-time polymerase chain reaction (QRT-PCR) and immunochemistry. During lactation, the pups ingested F and/or Pb via the maternal milk, whose mothers were exposed to sodium fluoride (150 mg/L in drinking water) and/or lead acetate (300 mg/L in drinking water) from the day of delivery. After weaning at postnatal day 21, the pups were exposed to the same treatments as their mother. At day 14 and at day 28, 6 pups (female:male = 1:1) were chosen randomly from each group for further investigation. Results showed that at postnatal days 14 and 28, the expression levels of NMDAR1 gene were increased by 11% and 26%, respectively, in pups exposed to F compared to the controls, and the protein levels were also significantly enhanced. In pups exposed to Pb alone and to Pb plus F, the levels of the NMDAR1 gene and protein were decreased at postnatal day 14 and then increased at postnatal day 28. These results may provide evidence of a relationship between the excitotoxicity and neurotoxicity of F and/or Pb.