Role of Dopamine in Parkinson's Disease

Parkinson's disease is a brain disease in which nerve cells (neurons) in the substantia nigra, which produce dopamine, begin to die. Dopamine serves an important bodily function and helps with muscle control. When 80 percent of the nerve cells that produce dopamine die, the Parkinson's symptoms begin to present.

What is Dopamine

• Dopamine is a neurotransmitter. This means it helps cells to transmit signals between each other. It is one of the most important neurotransmitters in the body, and it allows cells necessary for movement, learning and behavior, to communicate with each other. The appropriate balance of dopamine in the brain is essential for the body to be able to coordinate muscle movement and to be able to move and function properly in daily activities.

Dopamine and Parkinson's

• Cells within the substantia nigra called basal ganglia are responsible for producing dopamine. If these cells cease this function when they become damaged, the body eventually becomes unable to send messages to muscles to move naturally. Parkinson's is a progressive disease, and although the symptoms may begin and be manageable or barely noticeable as dopamine levels first begin to drop, eventually dopamine levels in the body will continue to drop until Parkinson's symptoms become worse and worse. Parkinson's itself is not fatal, but when the dopamine levels are low enough a person will be entirely unable to move, function or care for themselves.

Causes of Low Dopamine Levels

• Although doctors and experts agree that low dopamine levels cause Parkinson's, there is no clear consensus as to why the cells in the basal ganglia that produce the dopamine die. According to the National Parkinson's Foundation, some experts believe that genetics causes the basal ganglia to stop functioning properly, while others believe environmental factors are responsible.

Effects on the Body

• Symtpoms of Parkinson's that appear when 80 percent of basal ganglia are not producing dopamine include shaking or tremors. Patients may become stiff or unable to balance or move quickly. Patients may begin to have trouble controlling facial expressions and speaking clearly. These symptoms become worse as dopamine levels drop lower and lower.

Treatment

• Parkinson's is not curable. The medications used to treat the disease primarily attempt to mimic the role that dopamine performs in the body. The most commonly used Dopamine replacement medication is called Levodopa. This can help to alleviate and reduce some symptoms temporarily and extend quality of life, but it will not resolve the underlying disease and dopamine levels generally continue to drop and exacerbate symptoms.