A commonly used hypertension drug may prevent the onset of Parkinson's disease, according to a new study published Monday on the website of New Scientist.
The drug prescribed for hypertension and stroke is isradipine ( or DynaCirc), which scientists believe blocks the same type of calcium channel.
Scientists at Northwestern University in Illinois, US, struggled to understand why the dopamine-producing brain cells which Parkinson's patients lose start dying and found that in young mice these cells use sodium channels to send signals, but in older mice they rely more on a certain kind of calcium channel.
This can prove deadly for a neuron because calcium accumulates inside the cell, eventually triggering a complete breakdown.
The scientists believed that isradipine (or DynaCirc) could help the cells revert to a younger state, and their experiments in a lab dish showed that exposing cells to the drug caused them to increase their use of sodium-based signaling.
The research team by James Surmeier implanted a time-release capsule of the drug beneath the skin of mice that had just reached adulthood. This implant released a daily dose of isradipine that, if scaled up for humans, would correspond to roughly 10 times the dose for a person with hypertension, but less than the amount given to treat stroke.
A week after starting this regimen, the mice also began receiving bi-weekly injections of a chemical called MPTP that poisons the brain's dopamine-producing cells, the death of which simulates Parkinson's in mice.
Five weeks later, the mice receiving isradipine showed no outward signs of disease.
When the researchers tested the animals' ability to grip a wire mesh, the mice held on just as well as their control counterparts that had not received MPTP.
By comparison, the mice that received MPTP but not isradipine fumbled around showing symptoms of Parkinson's.
The research team plans to see whether isradipine can help mice that have already developed Parkinson's disease symptoms.
Human trials of isradipine are now planned. According to the report, the research team has already recruited a small group of Parkinson's patients to see if they can tolerate high doses of isradipine, which can cause side-effects such as headaches and dizziness.
The researchers are hoping to conduct a larger trial of the drug to find out if it can significantly slow the disease's progression.
Parkinson's patients lose a set of brain cells that produce the crucial signaling chemical dopamine, which do not regenerate, and without enough dopamine, people cannot control their body movements and ultimately develop severe neurological problems, including dementia.