PCBs may cause Parkinsons Disease.  PCBs alter dopamine levels in the brain.
Back to Parkinson's Table of Contents
PCB Human Health Risks
Fox River Watch
Site Index
Please give page time to load

parkinsons disease, parkinsons, parkinson disease, parkinson, parkinsons disease symptom, parkinsons symptom, information on parkinsons disease, parkinsons cause, cause of parkinsons disease, parkinsons disease cause, parkinsons diease, parkinsons medication, stage of parkinsons disease, definition disease parkinsons, disease parkinsons statistics, definition dopamine, dopamine drug, parkinsons statistics, parkingsons		 parkinsons disease, parkinsons, parkinson disease, parkinson, parkinsons disease symptoms, parkinsons symptom, information on parkinsons disease, parkinsons cause, cause of parkinsons disease, parkinsons disease cause, parkinsons diease, parkinsons medication, stage of parkinsons disease, definition disease parkinsons, disease parkinsons statistics, definition dopamine, dopamine drug, parkinsons statistics, parkingsons

Parkinson’s Disease, Dopamine and PCBs

parkinsons disease, parkinsons, parkinson disease, parkinson, parkinsons disease symptoms, parkinsons symptom, information on parkinsons disease, parkinsons cause, cause of parkinsons disease, parkinsons disease cause, parkinsons diease, parkinsons medication, stage of parkinsons disease, definition disease parkinsons, disease parkinsons statistics, definition dopamine, dopamine drug, parkinsons statistics, parkingsons
Introduction
 
The studies in this section demonstrate that PCBs affect the dopamine-producing processes of the brain, through changes in thyroid hormones and other chemicals in the body, which may lead to Parkinson's Disease.  Even low PCB doses cause changes in these chemicals in the brain. One surprising finding of the studies is that many non-dioxin-like PCBs, including some with low levels of chlorine, contribute significantly to dopamine deficits.

The lower-chlorinated PCBs are more likely to volatilize (evaporate) into the air we breathe, from the surface of the Fox River and Green Bay. As higher-chlorinated PCBs degrade over time, many are converted into lower-chlorinated PCBs. (Until recently, many believed that lower-chlorinated PCBs were non-toxic.)

Dopamine changes may make PCB exposed adults and newborns more vulnerable to the neurological disorder called Parkinsons Disease, particularly in those who are genetically susceptible.

The Definition of Parkinson's Disease

The brain is a mesh of cells which communicate and signal over long distances and are triggered by various stimuli. Dopamine is a neurotransmitter or chemical messenger in the body which affects brain processes controlling movement, balance, walking, emotional response, and ability to experience pleasure and pain. 
Parkinsons Disease, Parkinson Disease

As a chemical messenger, dopamine is similar to adrenaline. Dopamine allows the nervous system to communicate with the muscles in your body, translating thoughts into movements. Regulation of dopamine plays a crucial role in our mental and physical health. 

Parkinsons disease is caused by the selective loss of a relatively small area in the brain where 500,000 neurons, or dopaminergic cells. They are situated deep in the midbrain in a place called the substantia nigra. These dopamine-producing cells primarily form synapses (connections) in the front of the brain, in the corpus striatum, or caudate and putamen. 

In any brain that grows older, some of these neurons will die. The rate at which they die is individual. For certain people, whose rate of dopaminergic cell death is slightly higher than normal, the likelihood that they will eventually lose the critical 85- 90 percent of the cells that are needed for normal function is high. The brain somehow manages to compensate for a loss of about 85 percent of these cells, but when only a small number of functional dopamine cells or less remain on each side of the brain, the symptoms of Parkinson's disease appear. 

The neurotransmission that takes place at the nerve terminals that produce dopamine is necessary for all of us to initiate movements and without it, we freeze up and become unable to move. 

The brains of people with Parkinson's disease contain almost no dopamine. Currently, there is no cure for Parkinson’s disease, but drugs can relieve at least some of the symptoms. The cells in the brain are difficult to renew or regenerate by themselves, but researchers are experimenting with transplanting stem cells from humans or pigs into the substantia nigra of Parkinson’s patients, with some success in growing new neurons to create dopamine. 

A specific substance in our bodies, called tyrosine hydroxylase, produces a chemical called L-dopa, which in turn stimulates production of dopamine. Amino acid decarboxylase (AADC) is one of the two main enzymes (the other one being catechol-0-methyltransferase or COMT) that is responsible for converting L-dopa into dopamine in the bloodstream before it reaches the brain. 3-O-methyldopa is an inactive metabolite of levodopa produced in the periphery by COMT, also known as 3-OMD.

Acetylcholine is another chemical which acts as a neurotransmitter. An imbalance between dopamine and acetylcholine results in some Parkinson's disease symptoms.

In cell culture and preliminary animal studies, it has been shown that brain-derived neurotrophic factor (BDNF) can help dopaminergic neurons against toxic insults. Similar effects have been obtained by infusions and the supply of glial-derived neurotrophic factors (GDNF) and transforming growth factor ß (TGF-ß).

Back to top

parkinsons disease, parkinsons, parkinson disease, parkinson, parkinsons disease symptoms, parkinsons symptom, information on parkinsons disease, parkinsons cause, cause of parkinsons disease, parkinsons disease cause, parkinsons diease, parkinsons medication, stage of parkinsons disease, definition disease parkinsons, disease parkinsons statistics, definition dopamine, dopamine drug, parkinsons statistics, parkingsons
The Social and Economic Costs of Parkinson’s Disease
 
In the United States today, over one million people over the age of 65 are living with Parkinson’s Disease. 

Up to 1.5 million Americans are affected altogether, more persons than those suffering from Multiple Sclerosis and Muscular Dystrophy combined. Although 15% of patients are diagnosed before age 50, the disease generally targets older adults. 

Approximately one to two percent of persons above age 65 will develop the disease. 
 

 Parkinsons Disease, Parkinson Disease
Nationwide, drug therapy alone costs about six billion dollars per year and the cost of hospital care and other consequences associated with a person having Parkinsons disease is estimated at $25-50 billion per year. 

Back to top

parkinsons disease, parkinsons, parkinson disease, parkinson, parkinsons disease symptoms, parkinsons symptom, information on parkinsons disease, parkinsons cause, cause of parkinsons disease, parkinsons disease cause, parkinsons diease, parkinsons medication, stage of parkinsons disease, definition disease parkinsons, disease parkinsons statistics, definition dopamine, dopamine drug, parkinsons statistics, parkingsons
What Causes Parkinson’s Disease?

Most scientists believe Parkinson’s is caused by a poorly understood combination of genetic (inherited) susceptibilities and environmental factors, such as toxic chemical exposures.

As part of the World War II Veteran Twins Study, researchers examined 19,842 twins to distinguish whether genetics or environmental chemicals cause Parkinsons Disease (published in the January 27, 1999 issue of the Journal of the American Medical Association). They concluded that "environmental factors are the most common cause of the disease in "typical onset" patients (those diagnosed after 50 years of age). At the same time, genetic factors are the cause of Parkinson’s Disease in most "young onset" patients (those diagnosed prior to age 50)." 

Some drugs have been shown to interfere with the brain's metabolism of dopamine, and prolonged use can produce Parkinson features. These medications include: haloperidol and other medications used to treat hallucinations and confusion in the elderly; some anti-hypertensive drugs which contain reserpine; and a commonly prescribed anti-nausea drug, metoclopramide (Reglan). The chemical MPTP (1-methyl, 4-phenyl, 1,2,3,6-tetrahydropyridine), which was a byproduct of an illegal narcotic drug, also creates parkinsonism.

Several studies have shown an association between Parkinson's disease and pesticide exposure in agricultural areas. (Many pesticides are chlorinated organic compounds closely related to PCBs.) A recent study found that the pesticide Rotenone is strongly linked to Parkinson’s.

Neurotoxic chemicals are suspected of causing apoptosis or cell suicide in the substantia nigra (where dopamine is produced), a form of cell death in which cells shrink and disappear permanently.

Back to top

parkinsons disease, parkinsons, parkinson disease, parkinson, parkinsons disease symptoms, parkinsons symptom, information on parkinsons disease, parkinsons cause, cause of parkinsons disease, parkinsons disease cause, parkinsons diease, parkinsons medication, stage of parkinsons disease, definition disease parkinsons, disease parkinsons statistics, definition dopamine, dopamine drug, parkinsons statistics, parkingsons
What If the Brain Gets Too Much Dopamine?

A hyperactivity of the dopaminergic transmission or excess dopamine in the brain induces dyskinesia (uncontrollable movement of various body parts), dystonia (abnormal muscle tension and postures) and psychosis. Some researchers believe some schizophrenia and alcoholism cases may be the result of dopamine system malfunctions. 

Sometimes these changes in the brain are permanent. 

Many chemicals used as illegal drugs, such as amphetamine and cocaine, activate this part of the brain and stimulate dopamine production, to produce euphoria. Over time, this may damage the dopamine-producing cells through over-stimulation.

Back to top

parkinsons disease, parkinsons, parkinson disease, parkinson, parkinsons disease symptoms, parkinsons symptom, information on parkinsons disease, parkinsons cause, cause of parkinsons disease, parkinsons disease cause, parkinsons diease, parkinsons medication, stage of parkinsons disease, definition disease parkinsons, disease parkinsons statistics, definition dopamine, dopamine drug, parkinsons statistics, parkingsons
Other Neurological Disorders

The dopamine-producing cells are not the only brain cells susceptible to chemical damage. Loss of other specific types of neurons in the brain can lead to other chronic neurological diseases. For example, Alzheimer's disease and Lou Gehrig's disease (Amyotrophic Lateral Sclerosis) are disorders where several different risk factors interplay. In each of these disorders, it is known that only a minority of patients, around 15 to 20 percent, has a family history suggestive of a major genetic (inherited) contribution to the cause. This means environmental causes (such as toxic chemical exposures) are likely for roughly 80 to 85% of cases.

PCBs affect development and function of several areas of the brain. Could PCBs be a factor in some cases of these degenerative diseases?

Back to top

parkinsons disease, parkinsons, parkinson disease, parkinson, parkinsons disease symptoms, parkinsons symptom, information on parkinsons disease, parkinsons cause, cause of parkinsons disease, parkinsons disease cause, parkinsons diease, parkinsons medication, stage of parkinsons disease, definition disease parkinsons, disease parkinsons statistics, definition dopamine, dopamine drug, parkinsons statistics, parkingsons
Symptoms of Parkinson's Disease

1. resting tremor on one side of the body; 
2. generalized slowness of movement (bradykinesia); 
3. stiffness of limbs (rigidity); and 
4. gait or balance problems (postural dysfunction). 
Other symptoms sometimes observed in Parkinson's patients include: 
1. Small cramped handwriting (micrographia); 
2. Lack of arm swing on the affected side; 
3. Decreased facial expression (hypomimia); 
4. Lowered voice volume (dysarthria); 
5. Feelings of depression or anxiety; 
6. Episodes of feeling "stuck in place" when initiating a step...called "freezing"; 
7. Slight foot drag on the affected side; 
8. Increase in dandruff or oily skin; 
9. Less frequent blinking and swallowing.
Go to Studies Involving PCBs & Dopamine

Back to top

parkinsons disease, parkinsons, parkinson disease, parkinson, parkinsons disease symptoms, parkinsons symptom, information on parkinsons disease, parkinsons cause, cause of parkinsons disease, parkinsons disease cause, parkinsons diease, parkinsons medication, stage of parkinsons disease, definition disease parkinsons, disease parkinsons statistics, definition dopamine, dopamine drug, parkinsons statistics, parkingsons
Text References

All information on Parkinson’s posted above (except references to PCBs) was condensed from articles on the website for the National Parkinson Foundation, Inc.

Calne, D. M.D., FRCPC. "Genes and Parkinson's Disease." Author is Director, Unversity of British Columbia, Neurodegenerative Disorders Centre, Vancourer Hospital and Health Sciences Centre, Vancourer, British Columbia 

Hubble, J M.D., "Genetics and Environment in Parkinson's Disease." Author is Co-Director, Parkinson's Disease Center of Excellence and Movement Disorder Clinic, The Ohio State University, a National Parkinson Foundation Center of Excellence. 

Tanner, CM M.D. and JW Langston, M.D. "Genetics and Parkinson’s Disease: Research Points to Environmental Causes; Efforts Now Directed Towards Factors Other Than Heredity." Authors’ address: The Parkinson's Institute, Sunnyvale, California, a National Parkinson Foundation Center of Excellence.
 

parkinsons disease, parkinsons, parkinson disease, parkinson, parkinsons disease symptoms, parkinsons symptom, information on parkinsons disease, parkinsons cause, cause of parkinsons disease, parkinsons disease cause, parkinsons diease, parkinsons medication, stage of parkinsons disease, definition disease parkinsons, disease parkinsons statistics, definition dopamine, dopamine drug, parkinsons statistics, parkingsons
Back to top
PCB Human Health Risks
Fox River Watch
Site Index
  
Make a Donation

parkinsons disease, parkinsons, parkinson disease, parkinson, parkinsons disease symptoms, parkinsons symptom, information on parkinsons disease, parkinsons cause, cause of parkinsons disease, parkinsons disease cause, parkinsons diease, parkinsons medication, stage of parkinsons disease, definition disease parkinsons, disease parkinsons statistics, definition dopamine, dopamine drug, parkinsons statistics, parkingsons

 
 


Parkinson's Disease and Dopamine