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)
(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)
(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.
(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)
(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.
(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.”
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
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].