Numerous epidemiological studies have shown an association between pesticide exposure and an increased risk of developing Parkinson's disease (PD). Here, we provide evidence that the insecticide dieldrin causes specific oxidative damage in the nigrostriatal dopamine (DA) system. We report that exposure of mice to low levels of dieldrin for 30 days resulted in alterations in dopamine-handling as evidenced by a decrease in dopamine metabolites, DOPAC (31.7% decrease) and HVA (29.2% decrease) and significantly increased cysteinyl-catechol levels in the striatum. Furthermore, dieldrin resulted in a 53% decrease in total glutathione, an increase in the redox potential of glutathione, and a 90% increase in protein carbonyls. α-Synuclein protein expression was also significantly increased in the striatum (25% increase). Finally, dieldrin caused a significant decrease in striatal expression of the dopamine transporter as measured by 3 H-WIN 35,428 binding and 3 H-dopamine uptake. These alterations occurred in the absence of dopamine neuron loss in the substantia nigra pars compacta. These effects represent the ability of low doses of dieldrin to increase the vulnerability of nigrostriatal dopamine neurons by inducing oxidative stress and suggest that pesticide exposure may act as a promoter of PD. *Corresponding Author: Gary W. Miller, Ph.D., Emory University -Center for Neurodegenerative Disease, Whitehead Biomedical Research Building 505K, 615 Michael Street Atlanta, GA 30322, Phone: 404.712.8582, Fax: 404.727.3728, Email: gary.miller@emory.edu Publisher's Disclaimer: This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final citable form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. Parkinson's disease (PD) is a chronic, progressive neurological disorder clinically characterized by resting tremor, bradykinesia, postural instability and rigidity (Marsden, 1984). Pathologically, PD presents as dopaminergic neuronal loss in the substantia nigra pars compacta (SNc), striatal depletion of the neurotransmitter dopamine (DA), the loss of neurochemical markers, such as the dopamine transporter (DAT), and the presence of Lewy bodies containing α-synuclein (Spillantini et al., 1997). Because only 5-10% of PD cases are thought to be primarily genetic in origin, investigation of the role of environmental factors in the pathogenesis of the disease is warranted (Dauer & Przedborski, 2003).
NIH Public AccessNumerous epidemiological studies have shown an association between pesticide exposure and an increased risk of developing PD Le Couteur et al., 1999;Priyadarshi et al., 2000;Semchuk et al., 1991Semchuk et al., ,1992. In addition, a correlation between the presence of th...