Actions of sodium fluoride on acetylcholinesterase activities in rats.

This study was carried out to observe the effects of sodium fluoride on acetylcholinesterase (AChE) activities in the cerebral synaptic membranes (SPM) and the peripheral red blood cells (RBC) of rats by in vivo and in vitro experiments. In the in vivo study, pregnant rats ingested ad libitum fluorinated drinking water (5, 15, 50 ppm F-) during their gestation and lactation. It was shown that the AChE activities of the SPM and peripheral RBCs in maternal rats exposed 5-50 ppm F- for 60 days were elevated significantly by 30.0-67.6% and 12.5-31.9% in a dose-dependent manner, respectively. The AChE activities of their offspring 80 days after birth were also increased (8.7-28.7% for SPM and 20.6-32.4% for RBC). In contrast, the AChE activities of SPM in vitro were inhibited by 5.0-50.0 mmol F-/L treatment in a time- and dose-dependent manner. Analysis with the Hanes plots suggested that the enzymesubstrate kinetics are consistent with a mixed type of inhibition.