Parkinson's Movement
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New finding Pesticides linked to PD found. And if you smoke pot1980s they sprayed Paraquat to kill plants !

Jan. 3, 2013 — For several years, neurologists at UCLA have been building a case that a link exists between pesticides and Parkinson's disease. To date, paraquat, maneb and ziram -- common chemicals sprayed in California's Central Valley and elsewhere -- have been tied to increases in the disease, not only among farmworkers but in individuals who simply lived or worked near fields and likely inhaled drifting particles.

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Pesticide poisoning

Now, UCLA researchers have discovered a link between Parkinson's and another pesticide, benomyl, whose toxicological effects still linger some 10 years after the chemical was banned by the U.S. Environmental Protection Agency.

Even more significantly, the research suggests that the damaging series of events set in motion by benomyl may also occur in people with Parkinson's disease who were never exposed to the pesticide, according to Jeff Bronstein, senior author of the study and a professor of neurology at UCLA, and his colleagues.

Benomyl exposure, they say, starts a cascade of cellular events that may lead to Parkinson's. The pesticide prevents an enzyme called ALDH (aldehyde dehydrogenase) from keeping a lid on DOPAL, a toxin that naturally occurs in the brain. When left unchecked by ALDH, DOPAL accumulates, damages neurons and increases an individual's risk of developing Parkinson's.

The investigators believe their findings concerning benomyl may be generalized to all Parkinson's patients. Developing new drugs to protect ALDH activity, they say, may eventually help slow the progression of the disease, whether or not an individual has been exposed to pesticides.

The research is published in the current online edition of Proceedings of the National Academy of Sciences.

Parkinson's disease is a debilitating neurodegenerative disorder that affects millions worldwide. Its symptoms -- including tremor, rigidity, and slowed movements and speech -- increase with the progressive degeneration of neurons, primarily in a part of the mid-brain called the substantia nigra. This area normally produces dopamine, a neurotransmitter that allows cells to communicate, and damage to the mid-brain has been linked to the disease. Usually, by the time Parkinson's symptoms manifest themselves, more than half of these neurons, known as dopaminergic neurons, have already been lost.

While researchers have identified certain genetic variations that cause an inherited form of Parkinson's, only a small fraction of the disease can be blamed on genes, said the study's first author, Arthur G. Fitzmaurice, a postdoctoral scholar in Bronstein's laboratory.

"As a result, environmental factors almost certainly play an important role in this disorder," Fitzmaurice said. "Understanding the relevant mechanisms -- particularly what causes the selective loss of dopaminergic neurons -- may provide important clues to explain how the disease develops."

Benomyl was widely used in the U.S. for three decades until toxicological evidence revealed it could potentially lead to liver tumors, brain malformations, reproductive effects and carcinogenesis. It was banned in 2001.

The researchers wanted to explore whether there was a relationship between benomyl and Parkinson's, which would demonstrate the possibility of long-lasting toxicological effects from pesticide use, even a decade after chronic exposure. But because a direct causal relationship between the pesticide and Parkinson's can't be established by testing humans, the investigators sought to determine if exposure in experimental models could duplicate some of the pathologic features of the disease.

They first tested the effects of benomyl in cell cultures and confirmed that the pesticide damaged or destroyed dopaminergic neurons.

Next, they tested the pesticide in a zebrafish model of the disease. This freshwater fish is commonly used in research because it is easy to manipulate genetically, it develops rapidly and it is transparent, making the observation and measurement of biological processes much easier. By using a fluorescent dye and counting the neurons, the researchers discovered there was significant neuron loss in the fish -- but only to the dopaminergic neurons. The other neurons were left unaffected.

Until now, evidence had pointed to one particular culprit -- a protein called a-synuclein -- in the development of Parkinson's. This protein, common to all Parkinson's patients, is thought to create a pathway to the disease when it binds together in "clumps" and becomes toxic, killing the brain's neurons.

The identification of ALDH activity now gives researchers another target to focus on in trying to stop this disease.

"We've known that in animal models and cell cultures, agricultural pesticides trigger a neurodegenerative process that leads to Parkinson's," said Bronstein, who directs the UCLA Movement Disorders Program. "And epidemiologic studies have consistently shown the disease occurs at high rates among farmers and in rural populations. Our work reinforces the hypothesis that pesticides may be partially responsible, and the discovery of this new pathway may be a new avenue for developing therapeutic drugs."

Other authors of the study included Lisa Barnhill, Hoa A. Lam, Aaron Lulla, Nigel T. Maidment, Niall P. Murphy, Kelley C. O'Donnell, Shannon L. Rhodes, Beate Ritz, Alvaro Sagastig and Mark C. Stahl, all of UCLA; John E. Casida of UC Berkeley; and Myles Cockburn of the University of Southern California. The authors declare no conflict of interest.

11 Replies

How much did one have to smoke?


Ok pesticides and herbicides are "in the dock" accused of a vital role in provoking Parkinson's Disease. So what caused PD in people prior to the invention of pesticide and / or herbicide chemicals?


interesting, my husband was a daily pot smoker for decades. always thought it could be correlated to his PD.


Smoking tobacco apparently reduces the risk of developing PD.I have no idea of the effect of cannabis but so often cannabis is smoked with tobacco , Maybe some effect even if mixed with cannabis

I smoked tobacco for something like 25 years. I have now stopped for 8 years and it was 2 years after stopping that I got my PD diagnosis. It is impossible to tell whether I would still be free of PD if I was still smoking. I do know the effect on my wallet.I noticed the price of 20 Marlboro the other day £7.80. Good grief.


I did the exact same thing smoked for 25 years stopped, two years later I was diagnosed with PD. There is no way I would smoke again but I have wondered about the smokeless cigarettes and also the nicotine gum, but am afraid of becoming addicted again and having no improvement in my PD symptoms.


There are the nicotine patches as well but I think its rather too late to worry about the benefit or otherwise of tobacco we already have pd and we're stuck with it. Oh well !


It has been stated by medical researchers that if we all lived to be 110 years old, we would all have Parkinson's. Prior to pesticides, people made soap using lye (now chemically similar to Sodium Laurel Sulfate (SLS). SLS is found in soap, shampoo, shaving cream, cosmetics, tooth paste, detergents, etc. It is what makes soap and other products foamy. We have been placing SLS inside our skull, outside our brain, into our blood, etc for over 200 years. It is amazing any of us are still alive. Man's worst enemy is man. SLS is a surfactant that makes water slippery and allows things like oil to mix with water.


Well yes we may have been exposing ourselves to SLS for 200 years and we also live alot longer than we did 200 yrs ago so what can I make of that?


James Parkinson first described PD in 1817. Before that it was known as Paralysis Agitans or something like that. Now I wonder how long before 1817 did PD or whatever it was called come into existence ?


Make yourself a drink and then sit back and enjoy this. Here is the answer. (Jon on this site is the presenter)


Well i didnt smoke POTbut i am a keen gardener MMM makes you wonder