Researchers
report the discovery of a possible link between a common insecticide and
the development of Parkinson's disease.
"We have found
fairly low-dose effects of permethrin, an insecticide used by the military
and on food crops" on a brain protein and dopamine uptake levels, reported
Jeffrey Bloomquist, a professor of toxicology and pharmacology at Virginia
Polytechnic Institute in Blacksburg. "These changes could lead to Parkinson's
disease," he told United Press International.
Bloomquist and
his colleague Bradley Klein, professor of neurobiology at the Virginia-Maryland
Regional College of Veterinary Medicine, also in Blacksburg, presented
results of their U.S. Army-funded research at the annual meeting of the
American Chemical Society.
They found low
levels of the insecticide -- commonly used to protect cotton, corn and
other crops from insect devastation -- were related to lower dopamine production.
A decrease in this neurotransmitter's production in the brain has been
linked in previous research to the loss of motor skills associated with
Parkinson's.
In addition,
permethrin, also used to "impregnate (troops') uniforms to repel insects,"
affected levels of the protein alpha-synuclein, Bloomquist said. His research
suggested too much of this protein could cause formation of Lewy bodies
-- fibrous clumps seen in the brains of Parkinson's patients.
Though changes
in the brain's neural pathways caused by permethrin exposure could lead
to Parkinson's, Bloomquist said the research has not established a conclusive
link. The changes are consistent with a pre-Parkinson's condition, but
not the full-blown disease, he explained, adding genetics also plays a
probable role in a person's susceptibility to Parkinson's.
The U.S. Army,
which funded the initial research, has indicated support for additional
studies, Bloomquist said.
"We want to
look at longer exposure to see if we get something that looks like full-blown
Parkinson's," he added. The results presented at the ACS meeting were based
on injections administered over relatively short, two-week periods.
The research
fits into a larger category of association between insecticides and Parkinson's.
One clue to the link is the relatively elevated risk for the disease in
areas where insecticides are commonly used.
"There has been
similar work done," said Dr. Charles Adler, professor of neurology at the
Mayo Clinic in Scottsdale, Ariz. "The epidemiological data suggest people
in rural areas have higher rates of Parkinson's."
Bloomquist's
results could help confirm other evidence that insecticides can contribute
to Parkinson's, Adler said.
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