The etiology of Parkinson's disease (PD) is largely unknown. Preclinical and epidemiological studies provide a strong link between old age, prior exposure to pesticides and the increased risk of developing Parkinson's disease. This is of particular relevance to the VA because military personnel are often exposed to environmental toxins, including pesticides, during deployment. Moreover, the veteran population is older than the U.S. population and thus at increased risk. Recent evidence supports a role for elevated biogenic aldehydes in PD. The work proposed will not only help to elucidate the mechanisms underlying Parkinson's disease, but it will determine whether agents that lower biogenic aldehydes may be neuroprotective in Parkinson's disease. The test agent and potential alternatives are FDA-approved drugs for which there is abundant information on their safety and efficacy. Therefore, if these preclinical studies show efficacy in models of PD, then they may be more easily tested clinically.