Parkinson's is a progressive neurological disorder that affects muscle control, balance and movement. Parkinson's disease is a degenerative disorder that gets worse over time. The disease commonly occurs after age 50 and is one of the most common nervous system disorders seen in the elderly. Dopamine plays a key role in the progression of Parkinson's disease.
Dopamine
Dopamine is a neurotransmitter, or chemical messenger. A neurotransmitter sends neurological information from one cell to another by releasing a chemical which transmits an impulse from one nerve to another nerve, muscle, organ or tissue. As a chemical messenger, dopamine affects brain processes that direct emotional response, ability to experience pain and pleasure and control movement within the body. Regulating the production of dopamine within the body affects both physical and mental health, according to the University of Texas.
Dopamine and Parkinson's Disease
Neurons are nerves that send messages over long distances in the body. Neurons containing dopamine collect in the midbrain, in an area known as the substantia nigra. In Parkinson's disease, the dopamine-transmitting neurons in the area slowly die, leaving people who have the disease with no dopamine. Without dopamine, the brain cannot properly send messages. Over time, this leads to a loss of muscle function. The National Institutes of Health explains that the reason why brain cells waste away is unknown.
Effects
As the neurons containing dopamine die, people will begin to notice the effects. Symptoms often appear mild at first, such as a tremor in the hand or a feeling of dragging the foot. As the disease progresses, automatic movements, such as blinking, will slow. People may experience constipation, difficulty swallowing, balance impairment, muscle aches and pains, drooling, stiffness in the muscles and shaking tremors.
It is also common for people to shuffle when they walk, have difficulty starting or continuing to move and lose fine motor skills such as writing. Many people with Parkinson's disease walk in a stooped position and may exhibit mental health impairments, such as anxiety, dementia, depression, memory loss, hallucinations and confusion.
Treatments and Dopamine
Physicians commonly use medications that simulate dopamine to help slow the progression of Parkinson's disease. A medication known as levodopa belongs to a class of medications called central nerve system agents and works by converting to dopamine within the brain. Another medication, carbidopa belongs to a class of medications known as decarboxylase inhibitors and works by preventing levodopa from breaking down before it reaches the brain. Physicians may also use a group of drugs known as dopamine agonists.
Dopamine agonists do not convert into dopamine but instead mimic the effects of dopamine. The Mayo Clinic explains that these medications are not as effective for treating Parkinson's disease. MAO B inhibitors, such as selegiline and rasagiline, prevent the breakdown of both naturally occurring dopamine and levodopa, while Catachol O-methyltransferase inhibitors prolong the effects of both carbidopa and levodopa.
Prognosis
As of 2010, no cure exists for Parkinson's disease and, if untreated, the disease will worsen until a person is disabled. Most people respond well to medications and can help alleviate or relieve symptoms for a time.
