Abstract

SUMMARY: Learning-memory behavior was tested in mice on a Y-maze after they drank water containing different concentrations of sodium fluoride. Impairment of the structure of the Gray I synaptic interface in the CA3 area of the hippocampus was analyzed quantitatively by electron microscopy and a computer imaging processor. The main results were: the learning ability of mice drinking water with a high concentration of sodium fluoride showed considerable deterioration, the thickness of post-synaptic density (PSD) was decreased, and the width of the synaptic cleft was markedly increased. The results suggest that impairment of learning capability of mice induced by fluorosis may be closely associated with pathological changes of synaptic structure in the brain.