Publication Date:
2014-11-21
Description:
ABSTRACT Titanium dioxide nanoparticles (TiO 2 NPs) have been used in environmental management, food, medicine, and industry. But TiO 2 NPs have been demonstrated to cross the blood–brain barrier and store up in the brain organization, leading to glutamate-mediated neurotoxicity. However, the neurotoxicity in the brain is not well understood. In this study, mice were exposed to 1.25, 2.5, or 5 mg/kg body weight TiO 2 NPs for 9 months, and the glutamate–glutamine cyclic pathway and expressions of glutamate receptors associated with the hippocampal neurotoxicity were investigated. Our findings showed elevations of glutamate release and phosphate-activated glutaminase activity, and reductions in glutamine and glutamine synthetase in the hippocampus following exposure to TiO 2 NPs. Furthermore, TiO 2 NPs significantly inhibited the expression of N -methyl- d -aspartate receptor subunits (including NR1, NR2A, and NR2B) and metabotropic glutamate receptor 2 in mouse hippocampus. These findings suggest that the imbalance of glutamate metabolism triggered inhibitions of glutamate receptor expression in the TiO 2 NP-exposed hippocampus. © 2014 Wiley Periodicals, Inc. Environ Toxicol, 2014.
Print ISSN:
1520-4081
Electronic ISSN:
1522-7278
Topics:
Energy, Environment Protection, Nuclear Power Engineering