Study of insecticide neurotoxicity yields clues to onset of Parkinson...( BLACKSBURG Va. March 24 2003 -- A gr...)

Jeffrey R. Bloomquist, a neurotoxicologist and associate professor in the university's Department of Entomology, will describe his findings as part of the International Award for Research in Agrochemicals, a symposium honoring Robert M. Hollingworth, at the annual meeting of the American Chemical Society in New Orleans this week.

"We found low-level exposures set in motion a process with an early onset that develops slowly and is persistent," Bloomquist said. "More surprising is that high-level exposures resulted in few immediate effects that we could observe, but in the longer term there was a delayed effect."

The Virginia Tech researchers studied the levels of dopamine, dopamine transporter protein expression, and the levels of a synaptic protein (alpha-synuclein) in mice exposed to various doses of the insecticide permethrin. The increase in dopamine uptake indicated the mouse's system was reacting to a neurochemical insult caused by the presence of the insecticide. The slow response to high levels of exposure to pesticides is caused, Bloomquist thinks, by the system being overloaded and only after a period of a few weeks is it capable of responding to the insult in the same way as low doses.

In some individuals, dopamine-producing neurons may be challenged by genetic factors or by previous exposure to other neurotoxins. For individuals with a genetic predisposition, exposure to permethrin may trigger chemical events in the brain that result in an increased risk for damage to the area of the brain that is selectively damaged in Parkinson's disease.

The loss of motor skills, resulting in symptoms such as muscle rigidity, shuffling gait, and a rhythmic tremor, has been linked to the loss of dopa
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Contact: Stewart MacInnis
macinnis@vt.edu
540-231-5863
Virginia Tech
24-Mar-2003