Researchers are investigating genes that code proteins responsible for producing dopamine.

Scientists believe that once in the brain, certain fetal or adrenal tissues produce dopamine.

Brain imaging devices indicate that the transplanted areas are producing dopamine, he said.

The adrenal glands, which lie above the kidneys, also produce dopamine.

The purpose was to replace cells responsible for producing dopamine, a chemical essential to that part of the brain controlling body movement.

These cells produce dopamine, a chemical messenger that is essential for normal muscle movement.

It involves implanting cells that produce dopamine into the brain.

When cells that normally produce dopamine die off, the symptoms of Parkinson's appear.

This is the part of the midbrain that produces dopamine involved in movement.

Levodopa is transported to the nerve cells in the brain that produce dopamine.