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June 11, 2007 -- A drug used to treat high blood pressure may help prevent and treat Parkinson's disease.
A new study shows that the calcium-channel blocker DynaCirc may curb Parkinson's disease by making old brain cells act like younger versions of themselves.
The study was conducted in mice, not people. But the findings deserve more research, note the researchers, who included James Surmeier, PhD.
Surmeier is Northwestern University's Nathan Smith Davis Professor and chairman of the physiology department.
"Our hope is that this drug will protect dopamine neurons, so that if you began taking it early enough, you won't get Parkinson's disease," Surmeier says in a Northwestern University news release.
The drug strategy may also help Parkinson's patients, Surmeier notes.
For instance, he points out that the main Parkinson's treatment -- a drug called levodopa (L-dopa) -- tends to lose its effectiveness over time. DynaCirc treatment may extend L-dopa's effectiveness, according to Surmeier.
"If we could double or triple the therapeutic window for L-dopa, it would be a huge advance," says Surmeier.
Parkinson's disease affects certain brain cells that make dopamine, a chemical that helps direct the body's movements.
In Parkinson's disease, dopamine-producing brain cells die. That lowers dopamine levels, causing movement problems that gradually worsen.
Surmeier's team analyzed the inner workings of brain cells (neurons) affected by Parkinson's disease.
As those neurons aged, they became unusually reliant on calcium channels. Healthy neurons need calcium channels to function, but not to the extent seen in Surmeier's study.
Relying heavily on calcium channels might stress those neurons, making them more vulnerable to Parkinson's' disease, the researchers reasoned.
Surmeier's team tested DynaCirc in mice.
First, the researchers split the mice into two groups. One group of mice got pellets implanted under their skin. The pellets slowly released DynaCirc. The other group got medicine-free pellets (placebos).
Next, both groups of mice were exposed to chemicals that induce Parkinson's-like symptoms.
DynaCirc treatment cut neuron loss by half and "prevented the development" of movement problems in the mice, the researchers report.
DynaCirc made the neurons act like young neurons, which don't rely so strongly on calcium-channel blockers. The researchers call it a "rejuvenation" process for those neurons.
The study appears online in Nature.