- While unproved, environmental toxins of industrial and or agricultural origin represent an attractive theory to explain the increasing incidence of degenerative diseases of the nervous system such as Parkinson's disease (PD). We have examined several chemicals utilized in an area of Israel previously demonstrated to contain a statistically greater than average number of people with Parkinson's disease. One of these agents, a light stabilizer employed universally in the production of polyolifins used in plastics, depleted primary mesencephalic cultures of dopamine neurons, and produced a dopamine-specific lesion of the substantia nigra pars compacta when injected stereotactically into the ventral midbrain of adult rats. The observed effects were dose-dependent. These findings represent a potentially significant development in the search for industrial/environmental causes of neurodegenerative disease.