Exercising Limbs May Help Parkinson's Patients

In an animal model of Parkinson's disease, exercise was found to prevent degeneration of nerve cells that are normally impaired or destroyed by the disease. Based on this finding, a small pilot study has been initiated in patients with the disease to determine if regular exercise can affect progression of the disease.

In Parkinson's disease, cells in the brain that contain dopamine, a neurotransmitter essential for purposeful and facile muscle control, progressively die until only a small percentage remains. Dopamine carries signals from the nerve cells, or neurons, located deep inside the brain in the substantia nigra along nerve fibers that end in the brain's striatum, an area involved in control of movement. In the absence of dopamine, neurons cannot send the appropriate messages for smooth motor control, resulting in the telltale symptoms of Parkinson's: uncontrollable tremors, rigidity of limbs, slow movements, and stooped posture.

Researchers examined the brains of rats that had been forced to exercise for seven days before receiving a toxin that normally induces Parkinson's. They found that, compared to animals that did not exercise, significantly fewer dopamine-containing neurons died. Proteins called neurotrophic factors protect neurons and promote their survival. One in particular, called GDNF, is increased with exercise by 40%.

"GDNF, and probably other factors as well, may help offset the cell's vulnerability to the effects of oxidative stress from free radical molecules that are produced by the toxin we use in our rat model,” explained Michael J. Zigmond, Ph.D., professor of neurology, neurobiology, and psychiatry at the University of Pittsburgh School of Medicine (PA, USA). Dr. Zigmond and colleagues are beginning a study whereby 20 patients with Parkinson's disease are enrolled in a 60-minute exercise program that meets three times a week.

"Our data suggest the possibility that exercise can make dopamine neurons resistant to neurotoxins and may therefore be a useful therapy for Parkinson's disease,” noted Annie D. Cohen, a doctoral student at the Pitt School of Medicine.





Related Links:
U. Pittsburgh Medical School