Mental Exercise May Help Prevent Parkinson's Disease

People who have Parkinson's disease may someday find themselves undergoing a mental training regimen that helps them respond better to the drugs they take and to avoid surgery.

But first, the results of animal studies by Richard E. Tessel and his colleagues must be found to work in humans.

"Our studies hint that exercising your brain every day might be just as important as 20 minutes of physical exercise," said Tessel, professor of pharmacology and toxicology at the University of Kansas.

Work by Tessel and Stephen R. Schroeder, director of the KU Institute for Life Span Studies, will appear in early 1998 in the journal Brain Research.

Most scientists interested in diseases like Alzheimer's and Parkinson's, which stem from massive loss of brain cells, focus on drugs and surgery, Tessel said.

But Tessel's work is related to research at other universities suggesting that lifestyle can make a difference in the progression of such diseases.

"Several have hinted that the more education you have, the less likely you are to get Alzheimer's or Parkinson's," he said.

The root cause of Parkinson's is the lack of a chemical messenger, dopamine, that serves as a relay between certain nerve cells in the brain.

The relationship of Parkinson's to dopamine is underscored in the name of the drug commonly used to treat Parkinson's: L-dopa.

In their experiments, Tessel and Schroeder used four sets of rats. Two of the sets contained normal rats. The other two sets contained rats that had had almost all of their dopamine-making cells killed, in effect inducing Parkinson's in them.

One set of normal rats and one set of Parkinson's rats were put through a training regimen that required them to push various levers different numbers of times to get food.

A second set of normal rats and of Parkinson's rats received no training.

After the training, Tessel and Schroeder gave all the rats a dopamine-like drug called apomorphine. They wanted to see if the trained Parkinson's rats that received apomorphine would behave better than the untrained Parkinson's rats that also got the drug.

The researchers found that the normal rats showed little change in behavior in response to the apomorphine, Tessel said, but the Parkinson's rats differed sharply in their response.

"The Parkinson's rats that had NOT been trained were highly excited and ran around in their cages after apomorphine," Tessel said. "The Parkinson's trained rats that received apomorphine acted exactly like the normal rats."

In experiments elsewhere, scientists have used rat-brain fetal tissue implants containing lots of dopamine-making cells to achieve a similar calm in rats that had had their dopamine-making cells killed off and then received a dopamine-like drug.

Tessel said he theorized that the training regimen helped by making more dopamine available in the brains of rats with induced Parkinson's.

If humans follow the same patterns, he speculated, training of some kind might reduce their need for L-dopa -- or the future equivalent of that popular drug -- or surgical therapy or maybe a combination of surgery and L-dopa.