FALL, 2000



Barbara Kapica
ESL 91
Fall, 2000


Essay Topic: Research one or more of the neurotransmitters in the brain. Explain how the neurotransmitter(s) work and what the function is in the body. Be sure to concentrate on how the neurotransmitter affects behavior. What happens when something goes wrong in the system? What treatments are there?

The proper function of the brain depends on many complicated chemical substances produced by brain cells. These chemicals are called neurotransmitters and they are carried through the brain via nerve cells, or neurons.Neurons are specialized cells that carry electrical signals or impulses.A typical neuron has three parts; the cell body, the axon, and the dendrites.Dendrites receive impulses from the axons of other neurons.Between dendrites and axons are synapses.

Neurotransmitters are very important chemicals because they allow for the communication between neurons.Dopamine is one of the most significant neurotransmitters.Dopamine is a transmitter substance found in the brain, especially in the limbic system, an area associated with emotional response.Normal levels of dopamine are very important.Less than normal levels of dopamine in the brain cause Parkinsonís disease.In contrast, more than normal levels are associated with schizophrenia.


The human brain is made up of a web of billions of cells called neurons.The neuron is the simplest element of nervous action.It is a single cell with three subdivisions: the cell body, the axon, and the dendrites. ď The dendrites are usually branched, sometimes enormously so.The axon may extend for a very long distance, and its end may fork out into several branches.Impulses from other cells are received by the dendrites; in order for the signal to be transferred to the next neuron, the signal must be converted from electrical to chemical energy. The axon then transmits the impulse to yet other neurons or to effector organs such as muscles and glands.Thus, the dendrites are the receptive units of the neuron, while the axon endings may be regarded as its effector apparatus.Ē(Gleitman, 1995, p. 19)

Dopamine and its importance

One of the neurotransmitters playing a major role is dopamine.Many of the concepts that apply to dopamine apply to other neurotransmitters as well.As a chemical messenger, dopamine is similar to adrenaline.Dopamine affects brains processes that control movement, emotional response and the ability to experience pleasure and pain. ď There are at least six different known forms of the dopamine receptors.The neuroatomical basis for the interaction of dopamine with its receptors is not clearly understood.However, the lock and key analogy is commonly used.In a neuron the lock, or receptor must recognize a certain key, in this case dopamine, before the neuron is activated.Ē(Elsworth, 1997, p. 7)

Regulation of dopamine is clustered in the midbrain in an area called the substantia nigra.In Parkinsonís disease, the dopamine transmitting neurons in this area die.As a result, the brains of people with Parkinsonís disease contain almost no dopamine.To help relieve their symptoms, these people receive L-DOPA, a drug that can be converted to dopamine in the brain. (Dopamine-A Sample Neurotransmitter, n.d.)

Parkinsonís Disease and the correlation with Dopamine

Less than normal levels of dopamine in the brain leads to Parkinsonís disease. Parkinsonís disease results from a degeneration of brain cells in the basal ganglia that produce dopamine. Parkinsonís disease is characterized by four main symptoms: tremors, muscle rigidity, posture instability, and akinesia the inability to move (The Neurotransmitter Dopamine and Parkinsonís Disease, 1997).Some Parkinsonís patients also experience a loss of facial expression, speech problems, anxiety, and dementia. ď However, the signs of Parkinsonís disease do not appear until approximately 80% of the dopamine has been lost in the striatum.For this reason, researchers have not only looked for cures for the disease but also for treatment methods that revive or replace enough substantia nigra so that the symptoms of Parkinsonís disease disappear.Ē(Elsworth, 1997, p. 7) Approximately one million Americans have this neurological disorder and more than 50,000 new patients are diagnosed each year.

The symptoms of Parkinsonís Disease can be controlled to some degree through medications.The drugs that are symptomatic therapies can be classified into three categories: those that reduce the motor symptoms, those that treat nonmotor symptoms, and those that treat complications that arise.

Levodopa is one temporary solution.The drug enters the brain and is transported into cells that can convert it into dopamine in the striatum.Higher doses of levodopa can make up for the decreasing number of cells but may cause jerking movements of the limbs, trunk and head as well as hallucinations.Other drugs have been created which function in the same way that levodopa does, in that it is a substitute for dopamine, but the researchers have yet to find what causes the disease and eventually find a cure for it.

Schizophrenia and the correlation with Dopamine

Schizophrenia is a type of psychosis marked by delusions, hallucinations, apathy, and a split between thought and emotion.Two million people suffer from schizophrenia at some point in their life, making it one of the most common health problems in the United States.Schizophrenia has also been found to be hereditary.This biological disorder of the brain is a result of abnormalities which arise early in life and disrupt the normal development of the brain.These abnormalities involve structural differences between a schizophrenic brain and a healthy brain.The chemical nature of a schizophrenic brain is different in the manner the brain handles dopamine. In a schizophrenic brain there is too much dopamine. Also, schizophrenics tend to have abnormally low activity in the frontal lobes of the brain.

The disease schizophrenia can be characterized by disturbances in the areas of the brain that are associated with thought, perception, attention, motor behavior, emotion, and life functioning.The symptoms are divided into negative and positive categories.Negative symptoms consist of behavioral deficits such as blunting of emotions, language deficits, and lack of energy.Positive symptoms are frightening, but they are not as disabling in the long term as negative symptoms.These positive symptoms consist of hallucinations, delusions, and bizarre behavior.

The most common treatment for people with schizophrenia are antipsychotic drugs.The most common of these drugs include Thorazine and Haldol. ď These medications tend to reduce many of the major manifestations of schizophrenia, such as thought disorder and hallucinations. They are believed to act mainly by blocking synaptic receptors in pathways of the brain that are sensitive to dopamine.It is this blockade and the resultant decrease in dopamine activity that are generally thought to produce the therapeutic effectsĒ (Gleitman, 1995, p. 764).

Personal Response

By engaging in this research of dopamine and the effects it has on the body, I have learned a lot of new and fascinating things. Neurotransmitters help us receive the word, they allow us to see, feel, smell and taste. One of them is dopamine. I learned that dopamine is a very important neurotransmitter, which plays a major role in our brain. Many disorders are caused by improper levels of dopamine. Two very common are Parkinsonís disease and Schizophrenia. Thanks to this research, if in the future I meet someone with schizophrenia or Parkinsonís disease, I would understand that person much better because I have learned about the disease and how it affects that person.

One of the classes that I am taking this semester is Psychology 11, which is general psychology. By conducting this research I have learned more information about dopamine and its effects on the brain, which we did not discuss in my class. Therefore, this research helped me extend my knowledge about psychology.


The neurotransmitter dopamine plays an important role in our brain. Imbalance of dopamine activity can cause brain dysfunction and disease. Lack of dopamine can cause Parkinsonís disease, in which a person loses the ability to initiate controlled movements. Schizophrenia is thought to be brought on by the inability of dopamine to reach the frontal lobe. Too much dopamine in the limbic system may lead to paranoia.In both instances the cure has not yet been discovered.With the involvement of the celebrity, Michel J. Fox to find a cure for Parkinsonís disease, there has been more research done.But still the scientists have not yet found a cure.Dopamine is a significant neurotransmitter and improper levels of it affect our brain.


ďDopamine-A Sample NeurotransmitterĒ (no date). Retrieved on 10/31/2000, from the World Wide Web:

Elsworth, J.D. and Roth H R. (1997). "Dopamine Synthesis, Uptake, Metabolism, and Receptors: Relevance to Gene Therapy of Parkinsonís Disease.Ē Experimental Neurology 144 p.7

Gleitman H. (1995). Psychology Fourth Edition New York: W.W.Norton & Company,pp.19, 746

Gilbert T. and Roeder B. (1997). ďThe Neurotransmitter Dopamine and Parkinsonís Disease.Ē Retrieved on 10/31/2000 from the World Wide Web:

Return to Top of Page

Chong Caruso
ESL 91
Fall, 2000

Project Topic: Research one or more neurotransmitters in the brain. Explain how the neurotransmitter works and what its function is in the body. Be sure to concentrate on how the neurotransmitter affects behavior. What happens when something goes wrong on the system? What treatments are there?


Our brain is involved in many different areas, even the smallest muscular movement. Our muscular movement is worked by neurotransmitters, which are chemical messengers in our brain that move between nerve cells to other cells, through the synapse. This is how the brain communicates with other body muscles and translates into motion.


The nervous system receives and relays information about activities within the body, monitoring and responding to internal and external changes. Neurons are specialized cells that carry electrical signals or impulses. A neuron has three basic parts; the cell body, the axon, and the dendrites. Dendrites receive impulses from the axons of other neurons. Along the axon is a myelin coating with nodes in between each myelin sheath, Synapses, or small gaps, exist between dendrites and axons. Neurotransmitters are chemical substances that transmit nerve impulse across synapses. Neurotransmitters are the chemical messengers in our body (Kasper, 1998).


Dopamine is a specific neurotransmitter released by neurons in the brain. Dopamine is very important neurotransmitter both physically and psychologically in our brain. Dopamine is stored in vesicles on the outer membrane of the neuron. Dopamine is the one of the major neurotransmitters known as catechamines, which help the body respond to stress and prepare for the fight or flight responses (Kalat, 1986).

This neurotransmitter helps us when we are walking, sitting and doing other movements. Normal levels of dopamine in the brain allow the usual freedom of movement that we ordinarily experience. In the other hand, dopamine can disrupt the balance when dopamine level is low.

Low levels of dopamine neurotransmitters cause slowness of body movement, stiffness in the limbs and overall posture, and problems walking and keeping balance. Low levels of dopamine are related to Parkinson's disease. People with Parkinson's disease lose balance of body movements. Generally, Parkinson's disease affects elderly people. However, young people also could get Parkinson's diagnose before the age of 30.


Parkinson's disease is a slowly progressive disorder that affects body movement, muscular control, and balance. The main cause is loss of dopamine level. Parkinson's disease occurs when cells are destroyed in certain parts of the brain stem, particulary the corpus stratia. This causes problems in the nerves and muscles controlling movement and coordination, resulting in the major symptoms characteristic of Parkinson's disease (Kalat, 1986).


The first sign of Parkinson's may be as slight as a tremor in one finger. Overtime, the movement disorder may grow more pronounced, involving the hand and then the arms, usually on just one side of the body. As the illness progresses, walking may become slow and the balance may become unsteady. Depression is common along those who have this illness (, 1999).


Treatment is flexible and varies according to the stages of the disease. If a patient is in the early stages, the doctor may suggest a program of exercise and diet before drugs are prescribed. The medication most commonly used is Levodopa or L-dopa, a drug that is converted to dopamine in the brain. In the late stages of the disease, if drug therapy no longer works, several kinds of brain stimulation may also be an option, through these methods are not a cure and are considered a last resort. (Kibuik, 2000)


For this project I read a lot of interesting information and I also read different articles about Parkinson's disease. One article I read was about a young girl who was a Parkinson's patient when she was 21. Her name is Bremer and now she is 30. Bremer was diagnosed with the disease at 24. She had the characteristic tremors since age 21. Bremer started to notice shaking in her left hand. She never expected to have Parkinson's disease.

I also read about another case of a young man with Parkinson's disease. In 1999, Michael J. Fox revealed that he had had Parkinson's disease for the past seven years. His illness was diagnosed in 1999 after he noticed a " twitch" in his finger. He had a test for the illness and the results came back as the early stages of Parkinson's disease. Then he had brain surgery in March 1999 to lessen the tremors caused by illness.


I learned that Parkinson's disease is recently more frequent among both older and younger people. The National Parkinson's Foundation reported that two young patients had Parkinson's diagnosed when they were age 13. I had thought that Parkinson's disease is only for older people. In fact, I found out that Parkinson's disease occurs in young people too. Parkinson's disease is very hard to define, and it is hard to solve the problems that cause it.

Unfortunately, we haven't found a specific medication for this disease because the causes of Parkinson's disease are still unknown. All doctors and researchers are trying to find what can be helpful for the individuals suffering from this terrible illness. The National Parkinson's Disease Organization has found new drugs that are effective in the early stages of Parkinson's disease. However, these drugs are not cures. Recently, researchers are working more on Parkinson's disease and trying to develop protective therapies to safeguard the chemical dopamine in the brain. I hope that they will find the medications for Parkinson's disease in the future.

I learned so much important information about the neurotransmitters. Dopamine is a chemical in our brain that helps us in our body movements and balance. Without dopamine, we will have big problems in our body movement and balance. After I did this research, I really appreciated that I could walk, sit and do other movements. I also learned that dopamine level is very important for everyone. Normal levels of dopamine in the brain help us to have the freedom of movement that we normally experience. The presence of dopamine in the brain allows for movement. Dopamine controls our emotions and feelings, perception, and energy. Thus, dopamine also has to do with depression, anger management, problem resolution, and hyperactivity.


Dopamine is very important because dopamine plays a crucial role in our mental and physical health. This chemical in our brain is one of the major neurotransmitters. This chemical messenger, dopamine, affects brain processes that control movement, emotional response, and the ability to experience pleasure and pain. Parkinson's disease is caused by too little dopamine in the brain. Parkinson's disease is a terrible illness for older and younger people.

BIBLOGRAPHY (12/04/1999). "Exclusive Television Interview with Michael J. Fox " [Online]. (01/15/2000). "Too young for Parkinson's? " [Online]. (11/25/1999) "Michael J. Fox reveals he has Parkinson's disease" [Online].

Kalat, James W. (1986). Introduction to Psychology, Second Edition. pp. 73-74, 121-122.

Kasper, Loretta F. (1998). Interdisplinary English. New York: McGraw-Hill, p. 161-163.

Kibuik, Lydia. (11/03/2000). "Parkinson's and Dopamine." [Online]. (09/25/2000). "Parkinson's" [Online]. (10/19/2000). "Parkinson's disease" [Online]. (02/09/2000). "How our brain controls our movement and all about Parkinson's disease." [Online]. (11/05/2000). "A Sample Neurotransmitter" [Online].

Return to the Top of this page

Mushe Khoshayev
Fall, 2000

The Neurotransmitter Dopamine
The Brain
What is dopamine and how does it work?
How does dopamine affect our behavior?
What treatments are available?
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 Brain

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.

The Neurotransmitter

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.

Parkinsonís Disease:

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.

Return to the Top of this page

Return to the Fall, 2000 Start Page

Return to the ESL 91 Home Page

This page was last updated on December 12, 2000