WASHINGTON, March 27 (Reuters) - U.S. scientists have identified a chemical in tobacco that may explain why smokers are less prone to Parkinson's disease, according to a new study on laboratory rats released on Monday.
The chemical compound was shown by Virginia Tech researchers to slow the breakdown of key brain chemicals, including dopamine, which is typically depleted in the brains of patients suffering from Parkinson's, a debilitating disease that attacks the nervous system.
The findings were presented on Monday at the American Chemical Society's annual meeting in San Francisco.
``The association between smoking and Parkinson's disease has been known for more than 20 years, but until now could not be officially explained,'' the American Chemical Society said in a statement.
The tobacco compound was described as a derivative of naphthoquinone and works by interfering with an enzyme of the brain known as monoamine oxidase (MAO).
This enzyme typically breaks down neurotransmitters -- including dopamine, serotonin and norepinephrine -- as part of the normal chemical activity of the brain.
In their study, the Virginia Tech researchers gave laboratory rats MPTP, a designer drug that produces symptoms similar to Parkinson's disease. The drug was sold in the early 1980s and was aimed at mimicking the effects of heroin. Addicts who took large doses suffered severe Parkinson's symptoms.
The researchers found that the chemical compound naphthoquinone protected the rats against the toxic effects of the drug,
The statement said the researchers had started a second rodent study to confirm their initial findings.