Chronic fluoride toxicity decreases the number of nicotinic acetylcholine receptors in rat brain.

In order to investigate the molecular mechanism(s) underlying brain dysfunction caused by chronic fluorosis, neuronal nicotinic acetylcholine receptors (nAChRs) in the brain of rats receiving either 30 or 100 ppm fluoride in their drinking water for 7 months were analyzed in the present study employing ligand binding and Western blotting. There was a significant reduction in the number of [3H]epibatidine binding sites in the brain of rats exposed 100 ppm of fluoride, but no alteration after exposed to 30 ppm. On the other hand, the number of [125I]alpha-BTX binding sites was significantly decreased in the brains of rats exposed to both levels of fluoride.