The Neurotransmitter Dopamine
1. The Brain
3. What is dopamine and how does it work?
4. How does dopamine affect our behavior?
5. What treatments are available?
6. What did I learn from this research?
The human brain contains many different neurotransmitters. All these neurotransmitters are chemicals and they play a very important function in the human brain and body. Furthermore, different neurotransmitters do different functions in the human brain and body.
One of the neurotransmitters is dopamine. Dopamine does certain functions in the brain and body. It is important that the human brain produces normal amounts of dopamine. Otherwise, the human brain and body would have mental and physical dysfunctions such as Schizophrenia or Parkinsonís disease.
This project will focus on dopamine and explain what dopamine is and how it works. This project will describe dopamineís functions in the human brain and body. This project will also detail how dopamine affects our behavior. What happens when the personís system does not produce enough dopamine or when it produces more than needed? The project will conclude by describing treatments available for a person with dopamine dysfunction.
The human brain is a small organ and it weighs 1/45th of the human body (Myers, 1999). The brain has three major divisions: the brainstem, the cerebral hemispheres, and the cerebellum. The brain contains billions of neurons, which interact with each other through neurotransmitters. The neurotransmitters are chemical messengers, which travel through neurons. Through the activity of neurons and neurotransmitters, we learn, remember, and respond to any action around us. Every time when we feel, see, hear, touch, smell or taste something, million of neurons send messages to and from one another. These messages are sent through electrical impulses and chemicals, which are neurotransmitters. The neurotransmitters play a major role in receiving processing, and responding to information impulses.
Neurotransmitters are chemical messengers that travel through synaptic gaps between neurons. The sending neuron releases neurotransmitters into the synapse and the receiving neuron receives them. Therefore, this interaction will create a neural impulse, which sends the neurotransmitters to the brain through sensory neurons. Then we process those impulses and respond to them using our motor neurons. One of the neurotransmitters that travel through these neurons is dopamine.
What is dopamine and how does it work?
Dopamine is a chemical messenger that affects brain processes that control movement, emotional response and the ability to experience pleasure and pain. Therefore when we receive any information through our senses such as sight, smell, touch, hearing, and taste, the neurons become interactive and send messages to one another. Each neuron may have thousands of branches called dendrites, which receive neurotransmitters from† other neurons. The dendrites receive neurotransmitters like dopamine and carry them toward the cell body.
The cell body sends the neurotransmitters to the axons, which carry messages away from the cell body to another neuron. Through the activity of neurons the body responds and adjusts to changes in the environment (Addiction Science Research and Education Center, 1996).
How does dopamine affect our behavior?
Dopamine plays a very important role in our mental and physical health. For example, to use our senses or process any information and respond to it, we have to have a normal amount of dopamine in our brain and body. Therefore, the brain should produce a normal amount of dopamine to function properly. However, if the brain does not produce enough dopamine the brain and body can not function normally, as it should. People with insufficient dopamine function most probably would have Parkinsonís Disease and people with overactive function of dopamine most probably would have Schizophrenia.
The person with Parkinsonís Disease suffers an increasing motor behavior impairment, usually at an older age. The primary symptoms include muscular rigidity, resting tremor, difficulty with movement initiation, slowness of voluntary movement, difficulty with balance, and difficulty with walking. This disease was named after the English M.D. James Parkinson, who in 1817 was the first person to describe these symptoms as the shaking palsy (Bernstein, 1995; Wichmann & Delong, 1993). The brain of the person with Parkinsonís Disease contains almost no dopamine. To help to relieve the personís symptoms, the neurologists created the drug L-dopa. When the patient receives this drug L-dopa, it converts to dopamine in the personís brain† and helps the brain to function normally.
†When the person has overactive dopamine in the system we see symptoms of schizophrenia. Because of this overactivity of dopamine, the schizophrenic person has symptoms such as hallucinations, delusions, positive formal thought disorder, bizarre behavior, directed behavior (avalition), restricted fluent and productive thought and speech (Myers,1999). To help to relieve the personís symptoms of schizophrenia, the neuroscientists created a class of drugs called dopamine antagonists. Dopamine antagonists could prevent the overactivity of dopamine and stimulation of dopamine activity in the schizophrenic brain. Therefore, when the schizophrenic person receives a dopamine antagonist drug then s/he will function normally.
What treatments are available?
There has been a lot of research done, where neurologists found the components of drugs to heal people with Parkinsonís Disease and Schizophrenia. The neurologists created the drug L-dopa, as well as dopamine agonists and antagonists. Dopamine agonists bind to dopamine receptors in place of dopamine and directly stimulate those receptors. Therefore, the person with Parkinsonís Disease can be treated with such a drug and the personís brain can function normally.
††††††††††† In contrast to dopamine agonists, dopamine antagonists are drugs that bind to, but do not stimulate dopamine receptors. Antogonist drugs can prevent or reverse the action of dopamine by keeping dopamine from attaching to receptors (Addiction Science Research & Education Center, 1996). For that reason, dopamine antagonists are used to treat schizophrenia and related mental disorders. The dopamine antagonist can help regulate the personís system by preventing dopamine activity. Therefore, when the schizophrenic person is treated with a dopamine antagonist drug, s/he could function properly.
What did I learn from this research?
Researching about the neurotransmitter dopamine, I discovered for myself that neurotransmitters play a major role in our mental and physical health. For example, when we use our senses: sight, hearing, touch, smell, and taste, or do some activities, there are billions of neurons that become involved automatically. Through the activities of the neurons and neurotransmitters, we can do a lot of different things. We can understand, analyze, and respond to information that we receive. I learned that these tiny chemical substances such as dopamine are very powerful and without them we can not function properly and can not communicate normally with one another. Our body and brain use these tiny chemicals twenty-four hours a day. It does not matter what we are doing; we always use them, even when we sleep. Furthermore, I learned that if a personís brain does not produce enough or if the brain has an over amount of dopamine that the personís brain and body system can not function normally. This dysfunction of the brain and body creates diseases such as Parkinsonís Disease and Schizophrenia.
Through a lot of different research, the neurologists have discovered all about the neurotransmitter dopamine. We can see, that dopamine is a chemical messenger that affects the brain and body processes. Through this project we can understand the importance of these neurotransmitters in our mental and physical health. In addition, we can analyze and understand about some diseases such as Parkinsonís Disease and Schizophrenia. People with Parkinsonís Disease have underactive function and people with Schizophrenia have overactive function of the neurotransmitter dopamine in the brain and body. We know that Parkinsonís Disease and Schizophrenia can be treated with drugs such as dopamine agonists and antagonists. Now we can understand how these tiny chemicals work and what a major function they play in our brain and body.
Addiction Science Research and Education Center, (1996).† College of Pharmacy, University of Texas, Austin,† TX78712
Bernstein,† K.† (1995).† A Parisonís Primer. New Jersey: Prentice Hall.
Myers,† D.† G.† (1999).† Exploring Psychology.† 4th-edition. New York: Worth.
Wichmann,† T. & DeLong,† M.R.† (1993).† Pathophysiology of Parkinsonian Motor Abnormalities.† Advances in Neurology, 60, 53-61.