Dopamine and Parkinson's Disease

In this week's class, one of the topics we discussed was neurotransmitters and their function/influence in the neural system. One of these neurotransmitters, the dopamine pathway, is responsible for the regulation of motor activity, motivation and pleasure. However, excess dopamine receptor activity is linked to schizophrenia. Starved of dopamine, the brain produces the tremors and decreased mobility of Parkinson's disease. The connection to Parkinson's was very personal to me. A close family friend of our's has Parkinson's, and perseveres through its struggles every day. I decided to research Parkinson's disease, and provide a background into what causes it, what its symptoms are, and and how it is treated.

Parkinson's disease is a progressive disorder of the nervous system that affects movement. It develops gradually, sometimes beginning with an almost inconspicuous tremor in just one hand. While the tremor may be the most visible sign of Parkinson's disease, the disorder also commonly causes stiffness or slowing of movement. In early stages of Parkinson's disease, the face may show little or no expression, or the arms may not swing as one walks. Speech can become soft or slurred. Parkinson's disease symptoms worsen as the condition progresses over time.

The cause of Parkinson's disease is unknown, but several factors appear to play a role, including: 1) Genes. Researchers have identified specific genetic mutations that can cause Parkinson's disease, but these are extremely uncommon, except in rare cases with many family members affected by Parkinson's disease. However, certain gene variations (polymorphisms) appear to increase the risk of Parkinson's disease, but with a relatively small risk of for each of these genetic markers. 2) Environmental triggers. Exposure to certain toxins or environmental factors increase the risk of later Parkinson's disease, but the risk is relatively small.

Parkinson's disease symptoms and signs may differentiate from person to person. Early signs may be slight and may go unobserved. Symptoms often begin on one side of the body and usually remain worse on that side, even after symptoms begin to affect both sides. Parkinson's signs and symptoms may include: 1) Tremor. Tremors, or shaking, usually begins in the limb, often in the hands or fingers. One may notice a back-and-forth rubbing of the thumb and forefinger, known as a pill-rolling tremor. One characteristic of Parkinson's disease is a tremor of the hand when it is relaxed, or not being used.
2) Slowed movement (bradykinesia). Over time, Parkinson's disease may reduce the ability to move and slows movement. This may make simple tasks difficult and time-consuming. Steps may become shorter when walking, or one may find it strenuous to get out of a chair. Also, the feet may stick to the floor when trying to walk, making it complicated to move. 3) Rigid muscles. Muscle stiffness may occur in any part of the body. The stiff muscles can limit range of motion and cause pain. 4) Impaired posture and balance. Posture can become stooped, or balance problems can be a result of Parkinson's disease. 5) Loss of automatic movements. In Parkinson's disease, one may have a decreased ability to perform unconscious movements, including blinking, smiling or swinging the arms when walking. Gestures can become nearly obsolete when talking. 6) Speech changes. Speech problems can occur as a result of Parkinson's disease. One may speak softly, quickly, slur or hesitate before talking. Speech may also be more of a monotone, rather than with the usual rhythms. 7) Writing changes. Writing may appear small and become difficult.

Parkinson's can also develop thinking difficulties, depression and emotional changes, sleep problems and sleep disorders, bladder problems, constipation, and sexual dysfunction.

Medications are used to target these symptoms. These medications increase or substitute for dopamine.

Because the cause of Parkinson's is unknown, definitive ways to prevent the disease also remain a mystery. However, some research has shown that caffeine — which is found in coffee, tea and cola — may reduce the risk of developing Parkinson's disease. Green tea also may reduce the risk of developing Parkinson's disease.

If you are interested in learning more about Parkinson's disease, many websites, such as Mayo Clinic provide some great information.

Source: http://www.mayoclinic.com/health/parkinsons-disease/DS00295