ABSTRACT
<p><b>OBJECTIVE</b>To study the accumulation of fluoride in rat hippocampus and its effect on cholinesterase activity.</p><p><b>METHODS</b>Rats were subchronically exposed to NaF, and fluoride concentration and cholinesterase activity in rat hippocampus were determined.</p><p><b>RESULTS</b>Fluoride concentration in rat hippocampus was significantly correlated with the dosage of fluoride, and there were significant differences among high dosage group [(13.03 +/- 1.79) micro g/g], low dosage group [(9.83 +/- 0.92) micro g/g] and control [(8.27 +/- 1.11) micro g/g], P < 0.01. Acetylcholinesterase activities among three groups [(0.111 +/- 0.031) micro mol/mg, (0.143 +/- 0.025) micro mol/mg, (0.183 +/- 0.027) micro mol/mg] were also significantly different (P < 0.01), which was negatively correlated with fluoride concentration in rat hippocampus (r = -0.700, P < 0.01). The activity of butylcholinesterase in high dosage group [(0.041 +/- 0.010) micro mol/mg] was different from that of control [(0.067 +/- 0.025) micro mol/mg, P < 0.05], but the activity was not significantly related with fluoride concentration in rat hippocampus (r = -0.317, P = 0.094).</p><p><b>CONCLUSION</b>Fluoride may go through the blood-brain barrier and accumulate in rat hippocampus, and inhibit the activity of cholinesterase.</p>