BLACKSBURG, Va., May 19, 2000 -- In a discovery that opens an important direction in the study of Parkinson's disease, Virginia Tech scientists have identified a compound in tobacco that inhibits an enzyme that breaks down key brain chemicals.
Parkinson's disease, a central nervous system disorder, causes the gradual deterioration of neurons in the section of the brain that controls movement. The brains of patients with Parkinson's disease typically have less of a neurotransmitter called dopamine. Studies have shown that smokers are 50 percent less likely to get Parkinson's than non-smokers, but no one has isolated a particular substance in tobacco that may be responsible for that phenomenon.
Neal Castagnoli, director, and Kay Castagnoli, senior research associate, at Virginia Tech's Harvey W. Peters Center in the chemistry department, located in the College of Arts and Sciences, conducted research that has lead to the isolation of a compound in tobacco that protects against the loss of dopamine in mice and thereby may protect against the development of Parkinson's Disease.
"Joanna Fowler, a scientist at Brookhaven National Laboratory in New York, found by positron emission tomography (PET) imaging that smokers' brains have 30 to 40 percent lower levels of monoamine oxidase (MAO)," Kay Castagnoli said. MAO normally breaks down neurotransmitters such as dopamine, serotonin, and norepinephrine. Since the Castagnolis had already been conducting research involving MAO and neuroprotection, "We thought about the connection," Castagnoli said.
They decided to examine if there was a substance in tobacco that inhibits MAO. Ashraf Khalil, a postdoctoral fellow in the group, was able to separate and characterize a compound called 2,3,6-trimethyl-1,4-napthoquinone, or TMN, which was also known to be present in tobacco smoke and proved to be an inhibitor of MAO.
Using mice, the Castagnolis first administered TMN and then a potent neurotoxin, MPTP, a c
'"/>
Contact: Kay Castagnoli
kcastagn@vt.edu
540-231-8200
Virginia Tech
18-May-2000