WASHINGTON Nicotine may help ease some of the debilitating and uncontrollable tremors and twitches caused by Parkinson's disease and its treatment, researchers said on Wednesday.
Monkeys given a nicotine-laced drink before drug treatment for Parkinson's showed a 50 percent reduction in movements associated with the treatment. They showed a 35 percent drop in the movements, known as dyskinesias, when given the drink after treatments.
The finding, to be published in the Annals of Neurology, suggests it may be possible to improve the lives of patients who have very limited options.
"It may be the only drug that is useful for reducing dyskinesias without making Parkinson's disease worse," Maryka Quik of the Parkinson's Institute and Clinical Center in Sunnyvale, California, who led the study, said in a telephone interview.
Parkinson's disease, which affects more than 1 million patients in the United States, is marked by the death of brain cells that produce dopamine.
Dopamine is a neurotransmitter, or message-carrying chemical, associated with movement. Drugs can delay symptoms for a while but there is no good treatment and no cure.
The main treatment, levodopa or L-dopa, itself causes the abnormal involuntary movements after a time.
For years, researchers had noted that people who smoke and who drink coffee seemed to have a lower risk of Parkinson's, and some research has suggested that nicotine might protect brain cells and nerves in some way.
Quik said her team's findings appear to uncover a separate effect of nicotine.
The researchers caused Parkinson's in rats and then in monkeys by damaging the area of the brain where dopamine is made. They gave them a soft drink with nicotine before and after administering levodopa.
"Not only is nicotine neuroprotective, it protects against L-dopa-induced dyskinesias. The two effects are exclusive," Quik said. Nicotine did not appear to interfere with the beneficial effects of L-dopa.
Her team is now working with companies that make nicotine-like drugs to work up a trial in people.
The key is probably chemical doorways into brain cells called nicotinic receptors, Quik said. Drugs that work to affect these more precisely than nicotine does might also work better and more safely in people.
Nicotine patches are available over-the-counter for people who want to stop smoking but Quik did not advise that Parkinson's patients try them.
"It is very important to work out the proper conditions and the proper dose," she said.