Amphetamines — especially the drug known as ecstasy — may prompt new Parkinson's treatments, based on tests done on mice.
The researchers certainly don't recommend ecstasy for people with Parkinson's. The tests were done on mice, not people, and ecstasy can be dangerous for the brain.
But the findings reveal new clues about the brain disease and might one day lead to new treatments, write the researchers. They included Duke University cell biologist Tatyana Sotnikova, PhD, MSci. The report appears in Public Library of Science Biology.
About Parkinson's Disease
In Parkinson's disease, certain brain cells falter and die. Those cells can't do their job, which is to make a chemical called dopamine.
The brain uses dopamine to guide movement. The dopamine deficit scrambles the brain's movement signals to the rest of the body.
Though Parkinson's has no cure, medicine can help manage symptoms. Many Parkinson's drugs — including levodopa — address the brain's dopamine shortfall. However, complications from long-term levodopa use can also hinder motion.
First, the researchers slashed dopamine levels in mice. The mice didn't have a gene needed to transport dopamine. The mice also got drugs that knocked out most dopamine production. That left the mice with a condition like Parkinson's disease.
Next, the mice got drugs to see what eased their movement symptoms. Levodopa and other drugs that affect dopamine worked. So did several amphetamines. That surprised the researchers, who saw the biggest results with MDMA (ecstasy).
Amphetamines didn't work like levodopa and the other dopamine drugs. Instead of traveling through the brain's dopamine system, amphetamines took another route, but the path isn't clear yet.
Lots of questions remain, starting with ecstasy's brain dangers.
The researchers had to give the mice high levels of ecstasy to ease the mice's symptoms. Those drug levels might be much too much for the brain. Mice "are generally less sensitive" to ecstasy's toxic brain effects, write the researchers.
Work also needs to be done to understand how ecstasy worked. Once scientists figure that out, they might be able to create new Parkinson's drugs, write Sotnikova and colleagues.
SOURCES: Sotnikova, T. Public Library of Science Biology, August 2005; online edition. WebMD Medical Reference from Healthwise: "Parkinson's Disease — Medications." News release, Public Library of Science.