Parkinson's disease is caused by death of specific cells in the brain that produce the neurotransmitter dopamine. The death of these cells results in difficulty controlling movements and other psychiatric problems. Increasing dopamine levels in the brain via medication or supplements can reduce the severity of symptoms. However, dopamine therapy cannot stop the progression of the disease.
About Parkinson's
During the development of Parkinson's Disease, dopamine-producing brain cells in an area of the brainstem called the substantia nigra die. As of 2011, science does not know what causes these cells to die. As these cells die, they cannot supply dopamine to the rest of the brain. A constant supple of dopamine is necessary for normal brain function. The falloff in dopamine makes it more difficult to initiate voluntary movements and may also cause involuntary movements called tremors. Other psychiatric symptoms can include anxiety, confusion, depression, dementia and memory loss.
Role of Dopamine
Cells in the substantia nigra are continuously releasing small amounts of dopamine throughout the brain. Your brain can increase or decrease the activity of certain brain regions by increasing or decreasing the amount of dopamine. Loss of dopamine causes inactivity in brain regions such as those involved in movement control, making it difficult to start or stop movements. Increasing the supply of dopamine to the remaining cells of the substantia nigra can decrease the severity of symptoms by increasing the amount of dopamine supplied throughout the brain.
Dopamine Replacement
Levodopa, or L-dopa, is a drug commonly prescribed to treat Parkinson's disease that is a precursor to dopamine. Not all L-dopa enters the brain and can cause significant side effects from the increase in adrenaline, a related neurotransmitter produced by the adrenal glands. Other precursors of neurotransmitters, such as the amino acids L-tyrosine and L-phenylalanine, may also help increase dopamine levels, although research is not conclusive. Dopamine replacement does not stop the unknown process causing cell death in the substantia nigra and will not stop the progression of Parkinson's disease. Eventually cell death will proceed to the point that dopamine replacement therapy is ineffective.
Other Treatment
According to a 2003 commentary in "Molecular Psychiatry," oxidative stress may contribute to cell death in the substantia nigra. A healthy diet and lifestyle may help prevent this oxidative damage. The National Institutes of Health recommends avoiding stress, exercise and physical therapy and regular consumption of antioxidant rich vegetables. Deep brain stimulation can significantly reduce uncontrollable movements in some patients with moderate to severe Parkinson's disease.
References
- Pubmed Health; Parkinson's Disease; May 6, 2011
- "Principles of Neural Science," 4th ed.; E. R. Kandel , J. H. Schwarz and T.M. Jessel; 2000
- "Molecular Psychiatry"; Dopamine and Parkinson's Disease: Is the Killer in the House?; M-F Chesselet; 2003
