Brain Chemistry

I decided to take AP Language and Composition this year, and one of my summer assignments was to write a book report on any of the books in the recommended reading list. I chose the book The Man Who Mistook His Wife for a Hat by the neurologist Oliver Sacks, because it was one of the most compelling titles out of the bunch. When I started reading, I assumed that this story was a collection of accounts of cases of different mental disorders, which it turned out to be, but I was surprised to find there were some chemistry related aspects to it as well.

In one of the essays, “Witty Ticcy Ray,” Sacks recounted his encounter with a man, named Ray, who had a severe form of Tourette’s, a rare inherited neurological disorder that causes a person to experience frequent “tics” or spasms. (Encyclopædia Britannica, 2013) These tics result from “an excess of exciter transmitters in the brain, especially the transmitter dopamine (C8H11NO2).” (Sacks, 1985)

500px-Dopamine2.svg

(Harbin, 2008) – skeletal formula dopamine

Dopamine is a neurotransmitter, which is any group of chemical agents released by neurons (nerve cells) to stimulate neighboring neurons, allowing impulses to be passed from one cell to the next throughout the nervous system. (Encyclopædia Britannica, 2013)

Chemical_synapse_schema_cropped

(US National Institutes of Health, 2009) – impulse transmission in synapse

To treat his Tourette’s, his doctor, Sacks, prescribed haloperidol, otherwise known as Haldol, a drug that inhibits the formation of dopamine in his brain.

Haloperidol

(Fvasconcellos, 2007) – Skeletal formula of haloperidol

To me, one of the most interesting parts of the essay was Sack’s juxtaposition of Tourette’s and Parkinson’s disease. Where Tourette’s disease is an excess of dopamine, Parkinson’s disease is a lack of it. Parkinson’s is characterized by “muscle rigidity, difficulty and slowness in movement,” the opposite of the hyperactivity that characterizes Tourette’s. (Encyclopædia Britannica, 2013) In an analogy, having Tourette’s would be as if running at the speed of a cheetah, and having Parkinson’s would be as if crawling at the pace of a snail (although this reflects the more extreme cases of the diseases).

In both of these diseases, the causes of the abnormal dopamine production seems to originate from the “the thalamus, hypothalamus, limbic system and amygdala, where the basic affective and instinctual determinants of personality are lodged.” (Sacks, 1985)

limbic

(San Diego State University, n.d.) – Brain diagram

The lack of dopamine in a Parkinson’s patient is due to the loss of dopaminergic neurons that normally synthesize and use dopamine to communicate with other neurons in parts of the brain that control and regulate motor function.  To treat Parkinson’s, L-Dopa is given. (Encyclopædia Britannica, 2013)

An organic compound, L-Dopa (L-3,4-dihydroxyphenylalanine; C9H11NO4), also known as levodopa, is a precursor (in biochemistry, a compound that participates in a chemical reaction within a cell) to dopamine, and is able to cross the protective blood-brain barrier (a filtering mechanism of the capillaries that carry blood to the brain and spinal cord tissue, blocking the passage of certain substances). (Longe, 2006) Once L-Dopa is in the central nervous system, it is decarboxylated (the removal of the carboxyl (-COOH) group) into dopamine by the enzyme dopa decarboxylase (DDC), a catalyst, and pyridoxal phosphate (vitamin B6). (Porter, 2009) It then increases dopamine concentrations to “awaken” motor senses and restore the physical abilities of the Parkinson’s patients.

dopapathway-1

(NEUROtiker, 2007) – skeletal formulas and reactions of L-Dopa using biosynthesis

Sacks observed that his dopamine-deficient patients, when first introduced to L-Dopa, “were ‘awakened’ from stupor to health” and exhibited “wild excitements, violent impulses, often combined with a weird, antic humor.” (Sacks, 1985)

Although I do not know anyone who has Parkinson’s, I know that there is an estimated 10 million people worldwide that live with Parkinson’s, and approximately 60,000 people are diagnosed with it each year in the United States alone. (Parkinson’s Disease Foundation, 2013) Those numbers are scary, but my findings should be able to comfort those who have been affected by Parkinson’s. Whether a friend, family member, or themselves has Parkinson’s, I hope they will feel better knowing that there are methods of treatment that can help Parkinson’s patients lead relatively normal lives.

I did, however,  have a classmate in 8th grade who hit their head on the ground during P.E. and started experiencing restlessness and tics that he could not control. After my research, I can infer that that boy might have hit a certain part of his head to create an excess production of dopamine in his brain, and a possible treatment would be a prescription of Haldol, or another dopamine inhibiting drug.

I used to think that “something just went wrong with the brain” when thinking about neurological disorders, but my findings tell me that they are nothing to be afraid of, and that there are logical reasons behind these diseases. The advancement of medicine has come very far, and in the future I am sure there will be even greater advancements in this field. For example, a research project working on targeting dopamine-controlling drugs to the specific, affected part of the brain is currently underway. For more information on this study , here is a very interesting TedTalk on “brain chemistry.”

References

Human disease. (n.d.). Encyclopedia – Britannica Online Encyclopedia. Retrieved March 12, 2013, from http://www.school.ebonline.com/eb/article-63270

Levodopa. (n.d.). Encyclopedia – Britannica Online Encyclopedia. Retrieved March 12, 2013, from http://www.school.ebonline.com/eb/article-9472747

Longe, J. L. (2006). The Gale encyclopedia of medicine (3rd ed.). Detroit: Thomson Gale.

Porter, C. (2009, December 2). Chemistry of L-Dopa. Levodopa. Retrieved March 12, 2013, from students.cis.uab.edu/porce/page1.html

Sacks, O. W. (1985). The man who mistook his wife for a hat and other clinical tales. New York: Summit Books.

Statistics on Parkinson’s. (n.d.). Parkinson’s Disease Foundation. Retrieved March 12, 2013, from www.pdf.org/en/parkinson_statistics

Tourette syndrome. (n.d.). Encyclopedia – Britannica Online Encyclopedia. Retrieved March 12, 2013, from http://www.school.ebonline.com/eb/article-9073058

dopamine. (n.d.). Encyclopedia – Britannica Online Encyclopedia. Retrieved March 12, 2013, from http://www.school.ebonline.com/eb/article-9030951

neurotransmitter. (n.d.). Encyclopedia – Britannica Online Encyclopedia. Retrieved March 12, 2013, from http://www.school.ebonline.com/eb/article-9055391

Images

San Diego State University (2013). Limbic System. [image online] Available at: http://its.sdsu.edu/multimedia/mathison/images/limbic_system/limbic.gif [Accessed: March 12, 2013].

TedTalks (2013). David Anderson: Your brain is more than a bag of chemicals. Available at: http://www.youtube.com/watch?v=D9xJl4S6NsM [Accessed: March 13, 2013].

Unknown. (2013). Dopamine. [image online] Available at: http://commons.wikimedia.org/wiki/File:Dopamine2.svg [Accessed: March 12, 2013].

Unknown. (2013). Haloperidol. [image online] Available at: http://en.wikipedia.org/wiki/File:Haloperidol.svg [Accessed: March 12, 2013].

Unknown. (2013). Catecholamines biosynthesis. [image online] Available at: http://en.wikipedia.org/wiki/File:Catecholamines_biosynthesis.svg [Accessed: March 13, 2013].

US National Institutes of Health (2013). Chemical synapse schema cropped. [image online] Available at: http://en.wikipedia.org/wiki/File:Chemical_synapse_schema_cropped.jpg [Accessed: March 13, 2013].

One thought on “Brain Chemistry

  1. Looking at Caroline’s post on drugs that help to increase dopamine level in the body for Parkinson’s disease, I got curious about drugs that help decrease the dopamine level in the body to ease the effects of a certain disorder or disease. After doing some research, I came across a mental disorder called Schizophrenia, which is caused by inherited genes or different kinds of environment a person is exposed to. “Environmental stressors, such as harsh environment, high crime rate, and famine, early in development (during pregnancy and early childhood) can lead to subtle alterations in the brain that makes a person susceptible to developing Schizophrenia”(Schulman). The symptoms of Schizophrenia normally consists of auditory hallucination, delusions, paranoia. Everyone has experienced a different childhood, ranging from high social class to extreme adversity, and it is important to understand how it can affect our lives both physically and mentally and how it can be treated using antipsychotic drugs.

    In order to understand how the medicines work, we must first understand how the neurotransmitters are communicated between cells in the body to create that hallucination effect from Schizophrenia. In AP Psychology, I learned that excess dopamine and serotonin, both stimulating pleasure and happiness, are the two main neurotransmitters that create the mental disorder.

    In AP Biology, I learned about the process of the communication of neurotransmitters in the body. A neuron consists of a cell body and two types of cytoplasmic extensions called dendrites and axons. Before any action in a neuron, “the voltage potential is -65mV of a cell at resting potential.”(Farabee, 2010) “Sodium ions are more concentrated outside the membrane, while potassium ions are more concentrated inside the membrane”(Farabee, 2010), causing the cytoplasm to be positively charged and the membrane to be negatively charged. “This imbalance is maintained by the active transport of ions to reset the membrane known as the sodium-potassium pump.”(Farabee, 2010) When a stimulus is present, the neurons moves into actions potential where the gated-iofgrrn channels come into play.

    “An action potential is a temporary reversal of the electric potential along the membrane.” (Farabee, 2010) During actions potential, sodium channels open and sodium ions flood into the cell, down the concentration gradient. In response, potassium channels open and potassium ions flood out of the cell, as the signal is moving across the axon. The actions potential is like a row of dominoes falling in order after the first one is knocked over. The first action potential generates a second one, which continues to a third and a forth until the signal is passed on onto another cell.

    Finally, the impulse will cross a synapse chemically whereas the impulse travels along an axon electrically. The presynaptic neurons contain many vesicles, each containing thousand of molecules of neurotransmitters. Depolarization causes Ca++ ions to rush into the neuron through calcium-gated channels, and then the neurotransmitters are released through exocytosis. According to Macalester College, “when a neurotransmitter attaches to the postsynaptic neuron specific changes take place that depend on which neurotransmitter is involved. For Schizophrenia, dopamine and serotonin binds to the receptors and initiates hallucination and pleasure.

    So how does antipsychotic drugs such as Clozapine help relieve the disorder? When dopamine tries to bind to the post-synaptic receptors, “the antipsychotic drugs binds to the receptors first so the binding site is occupied.”(Zimmerberg); therefore, it decreases the activities of dopamine and serotonin in the body.The more neurotransmitters there are to bind to the receptors, the greater the response will be. With less dopamine and serotonin coming into effect, the probability of developing Schizophrenia is also reduced.

    It should be noted that over usage of Clozapine is also harmful. In AP Psychology, I learned that a severe decrease in dopamine level in the body can also lead to Parkinson’s diseases as mentioned in Caroline’s post. The shows that the usage of medicines like Clozapine, must be controlled so that the therapeutic effect can be maintained while at the same time limiting the side effects.

    While everyone experiences environmental stressors, there are countless people in the world who are more susceptible to the disease because they suffer from external pressure such as famine, poverty, and hostile parents. Schizophrenia is just one of the many disorders that we, living in a decent environment, will rarely encounter. It implies that even though we are fortunate enough to not infected by these types of disorders, it is still important for us to be well aware of these situations. People living in the more fortunate environment normally doesn’t care about this type of thing because they probably will never affect heir lives; however, a developed awareness on issues like these can better prepare the individual if he ever encounter such things. This is very similar to the club that I run, 30 hour famine. Even though in this school we don’t experience famine, the club still spreads awareness so people in the school are more susceptible about their world and environment. Any one of us could be a victim to environmental factors that we just don’t have control over. The fact that there are ways to reduce the effects of disorders suggests that a possible cure can also be developed. Many researchers today are working on developing these cures for most of the treatable diseases.

    Bibliography

    Farabee, M. (2010, May 18). The Nervous System. Online Biology Book. Retrieved April 8, 2013, from http://www.emc.maricopa.edu/faculty/farabee/biobk/biobooknerv.html

    Neurotransmission. (n.d.). Macalester College: Private Liberal Arts College. Retrieved April 8, 2013, from http://www.macalester.edu/academics/psychology/whathap/ubnrp/mdma/neurotransmission.html

    Schulman, B. J. (n.d.). Schizophrenia Cause and Prevention. Schizophrenia.com, Indepth Schizophrenia Information and Support. Retrieved April 8, 2013, from http://www.schizophrenia.com/hypo.php

    Zimmerberg, B. (n.d.). Dopamine Receptor Blockade: Antipsychotic Drugs. Williams College. Retrieved April 8, 2013, from http://web.williams.edu/imput/synapse/pages/IIIB5.htm

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