Fluoride Action Network


Effects of exposure of Swiss albino adult male mice to 17.6 mg NaF/L in their drinking water for up to 30 days on the NADPH diaphorase (NADPH-d) positive neurons in the forebrain were studied. Histochemical study by the method developed by Hope and Vincent for the distribution of NADPH-d positive neuron cell bodies was conducted in the cerebral cortex, hippocampus, amygdala, caudate putamen, and selected nuclei of the hypothalamus. Counting neuronal cell bodies, their dendritic intersections, and varicosities in the brain of the F-exposed mice showed significant increase in the neuron cell bodies. In the cerebral cortex, amygdala, and caudate putamen, the increase in the number of NADPH-d positive neurons and their dendritic intersections was highly significant (p<0.05), but no significant difference was seen in the dendritic branching. A significant increase in the number of varicosities was also observed in the brain of the F-treated mice. These results indicate that excessive F intake caused morphological changes in NADPH-d/NOS (nitric oxide synthase) positive neurons in the brain, thus increasing nitric oxide (NO) synthesis, which is implicated in F-induced neuron cell death. A possible mechanism of F neurotoxicity is thereby suggested.