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Scientists Find Nicotine May Ease Symptoms of Parkinson's
- Oct 24 2007
One of the more difficult challenges faced by sufferers of Parkinson's is not the disease itself, but rather the jerky, uncontrollable movements caused by the most common treatment for this devastating neurological disorder.
Now, scientists at the Sunnyvale-based Parkinson's Institute may have found a surprising, even ironic, treatment to reduce those movements: nicotine.
In a study released today, the scientists report that monkeys treated with nicotine had significantly fewer episodes of the jerky movements - known as dyskinesias - compared with monkeys that did not receive nicotine.
The study appears to be the first to examine nicotine as a treatment for dyskinesias, but it builds on a larger body of research that shows some promise for nicotine's ability to ease Parkinson's symptoms and reduce the disease's progression.
In the study, researchers gave nicotine-laced orange Gatorade to monkeys previously treated with a drug that mimics the symptoms of Parkinson's. They then gave the monkeys levodopa (L-dopa), a leading drug used to reduce the tremors and speech problems that are a hallmark of Parkinson's disease.
The researchers found that the nicotine-treated monkeys had up to 50 percent fewer episodes of dyskinesias, compared with monkeys that had not received nicotine before being given levodopa.
When the researchers gave the monkeys nicotine after treating them with levodopa, the monkeys experienced up to 35 percent fewer dyskinesias. In addition, the nicotine did not seem to worsen the disease itself. The study will be published in an upcoming issue of the Annals of Neurology.
"This is exciting, a good leap forward," said Jonathan Brotchie, a Parkinson's disease researcher with the Toronto Western Research Institute. "If you could see that sort of effect in patients with Parkinson's disease, it has the potential to increase the quality of their lives quite significantly."
However, Brotchie and other Parkinson's researchers not involved in the study cautioned against making too much of results, even promising ones, in monkeys. And, Brotchie said, because nicotine is potentially toxic in large doses and can create other health problems, researchers may have to develop a different drug that mimics how nicotine acts, rather than use nicotine itself.
"There is a lot that needs to be done to take this finding and turn it into a useful treatment," Brotchie said.
About 1.5 million Americans suffer from Parkinson's disease, with an estimated 60,000 new cases diagnosed each year. While the condition typically develops after age 65, about 15 percent of cases occur in people under 50.
The progressive disease occurs when nerve cells known as neurons in a certain part of the brain die or become impaired. These cells normally produce the chemical dopamine, which allows the body's muscles to move smoothly. When enough of those cells are damaged, the distinctive hand tremors, shuffling gait, rigidity and impaired speech may occur.
Treatments such as levodopa can reduce these symptoms, but at a cost: Many patients with the disease develop dyskinesias severe enough to prevent them from drinking from a cup, using utensils, getting dressed or walking, said the study's lead author, Maryka Quik of the Parkinson's Institute and Clinical Center.
Dyskinesias differ from the tremors that are the hallmark of Parkinson's in both scale and unpredictability: Quik described them as a broad, writhing or jerking movement of the arms, legs or body.
Dyskinesias can be treated by reducing the level of L-dopa, other medications and deep-brain stimulation, but each of those treatments carries its own side effects.
Nicotine may reduce jerky movements by normalizing the release of dopamine or by adjusting the levels of other neurotransmitters that control movement, although scientists don't know exactly how the process works.
Scientists have been studying nicotine's effects on Parkinson's disease for years, after decades of studies consistently showed that smokers seem to have about half the rate of Parkinson's disease as non-smokers.
This study, however, marks the first time anyone has examined the tobacco ingredient's effect on drug-induced dyskinesias, Quik said. She said that results of studies examining the beneficial effect of nicotine on Parkinson's disease have been mixed.
Dr. Graham Glass, an assistant clinical professor of neurology at the University of California-San Francisco, agreed that the jury is still out on whether nicotine, the tobacco component that makes smoking so hard to quit, could one day improve Parkinson's patients' lives.
Yet, he said, "I'm cautiously optimistic that it might be helpful therapeutically for patients."
If you're interested, call the Parkinson's Institute at (408) 734-2800 or visit www.thepi.org
Source Date: Oct 24 2007
Source Publication: San Jose Mercury News
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