Long-term exposure to endogenous levels of tributyltin decreases GluR2 expression and increases neuronal vulnerability to glutamate
- Graduate School of Biomedical Sciences, Hiroshima University, 1-2-3, Kasumi, Minami-ku, Hiroshima, 734-8553 (Japan)
Tributyltin (TBT), an endocrine-disrupting chemical, has been used commercially as a heat stabilizer, agricultural pesticide and component of antifouling paints. In this study, we investigated the effect of long-term exposure to endogenous levels of TBT on neuronal glutamate receptors. Cultured rat cortical neurons were exposed to 1-50 nM TBT for 9 days (from day 2 to day 10 in vitro). The number of neurons was reduced by long-term exposure to 50 nM TBT, but not to 1-20 nM TBT. Long-term exposure to 20 nM TBT decreased the mRNA expression of glutamate receptors NR1, NR2A, GluR1 and GluR2, and increased that of NR2B, GluR3 and GluR4. GluR2 protein was also reduced by long-term exposure to TBT. Because AMPA receptor lacking GluR2 exhibits Ca{sup 2+} permeability, we investigated whether Ca{sup 2+} influx or glutamate toxicity was affected. Indeed, glutamate-induced Ca{sup 2+} influx was increased in TBT-treated neurons. Consistent with this, neurons became more susceptible to glutamate toxicity as a result of long-term exposure to TBT and this susceptibility was abolished by an antagonist of GluR2-lacking AMPA receptor. Thus, it is suggested that long-term exposure to endogenous levels of TBT induces a decrease of GluR2 protein, causing neurons become more susceptible to glutamate toxicity.
- OSTI ID:
- 21272691
- Journal Information:
- Toxicology and Applied Pharmacology, Vol. 240, Issue 2; Other Information: DOI: 10.1016/j.taap.2009.06.024; PII: S0041-008X(09)00272-5; Copyright (c) 2009 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved; Country of input: International Atomic Energy Agency (IAEA); ISSN 0041-008X
- Country of Publication:
- United States
- Language:
- English
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