Parkinson's disease
In Parkinson's disease, for reasons that are not fully understood, nerve cells in the part of the brain that produces dopamine, the substantia nigra, begin to decrease in number. This causes a decrease in the amount of the available dopamine. Also, the chemical in the synapse that breaks down the dopamine (MAO-B) continues to deplete what little dopamine is left. The overall effect is a large loss of dopamine in the brain. This throws off the normal dopamine/acetylcholine balance, since the level of acetylcholine remains normal.
In Parkinson's disease, there is not enough dopamine to keep balance with the acetylcholine. The result of this imbalance is a lack of coordination of your movement that often appears as tremor, stiff muscles and joints, and/or difficulty moving. Currently, there is no way to stop the loss of nerve cells that produce dopamine or to restore those that have already been lost. However, there are several methods, including drug therapy, that can help you manage the slow decline in function that occurs with Parkinson's disease.
