The researchers caution that the findings in animals do not suggest Parkinson's disease patients should find relief by taking amphetamines, which are drugs of abuse with many dangerous side effects. The findings rather indicate that drugs with similar chemical attributes might offer useful alternatives to current therapies, the researchers said.
The new study also shows that amphetamines -- normally thought to act by increasing dopamine concentrations in the brain - correct the behavioral abnormalities associated with Parkinson's in mice devoid of the brain messenger. Dopamine normally acts on dopamine receptors - protein switches on the surface of neurons -- to stimulate brain processes that affect movement, emotion, pleasure and mood.
Parkinson's disease stems from the degeneration of neurons in a brain region that controls movement. That degeneration, in turn, leads to a shortage of the chemical messenger dopamine. The finding that amphetamines can alter movement independently of dopamine opens up new directions in the search for prospective anti-Parkinsonian drugs, the researchers said.
The researchers, led by James B. Duke professor of cell biology Marc Caron, Ph.D. and Assistant Research Professor Raul Gainetdinov, M.D., Ph.D., of Duke, made the discovery after testing the utility of more than 60 compounds for reversing Parkinson's symptoms in a mouse model of the disease. Developed by the Duke team, the mice lack detectable brain levels of dopamine and experience essentially all the symptoms of Parkinson's disease for several hours before recovering their normal behavior. Caron is also a researcher of the Duke Institute for Genome Sciences & Policy.