Nicotine Research Paper
The Chemical Effects of Nicotine on the Central Nervous System and the Adrenal Medulla
An Australian Health Survey conducted in 2011-2012 concluded that 3.1 million Australians are current smokers. (Australian Bureau of Statistics, 2013). This means that 14% of Australia’s population are current smokers compared to more than 40% in the 1980’s – a dramatic decrease with the smoking rate continuing to decline each year. Now there are many factors that can be considered for this drop such as the rise in prices or maybe less accessibility but another big factor is that it’s no longer seen in the same way socially like it was back in the 1980’s. With more and more anti-smoking products being created it decreases the amount of smokers and I’m …show more content…
going to go into more depth about that later on in the presentation.
But firstly, the question on everyone’s lips, why are so many people smoking?
What makes cigarettes so addictive? Well, I’m glad to tell you that’s why I am here today to explain and teach you about for the first half of this presentation. Cigarettes contain over 599 additives; one of those being Nicotine. Nicotine, also known in our chemistry world as 3-[(2S)-1-methylpyrrolidin-2-yl]pyridine – but you don’t have to concern yourself with that name – is the major additive in cigarettes responsible for their addictive qualities. Now if I say so myself, Nicotine is good at its job considering that there is typically only 1mg of Nicotine absorbed into the body per cigarette. Now Nicotine is a dangerous addicting drug because it has both psychological and physical addicting qualities, similar to heroin and cocaine, which makes the addiction that much harder to …show more content…
combat.
So what actually is Nicotine? Well, Nicotine is a parasymphatomimetic alkaloid from the nightshade family of plants called the Solanaceae. A parasymphatomimetic drug is “a drug or poison that acts by stimulating or mimicking the parasympathetic nervous system.” (Dorlands Medical Dictionary, 2013) Nicotine is also a nicotinic agonist. “A nicotinic agonist is a drug that mimics the action of acetylcholine at nicotinic acetylcholine receptors (NCR’s)” (Henningfield, 2006). Nicotine is administered orally. The body reacts as soon as Nicotine enters the body. Nicotine affects two different areas of the body: the adrenal medulla and the central nervous system.
The adrenal medulla is part of the adrenal gland found in the kidney. It has an impact on the body’s energy, heart rate and metabolism as it secretes hormones, such as adrenaline and dopamine. The kidney absorbs the Nicotine through the bloodstream which then enters the adrenal medulla. The Nicotine then binds with the nicotinic receptors which causes adrenaline to be released into the body; this causes common symptoms of smoking such as an increase in heart rate and blood pressure.
Dopamine is a hormone which is influenced by Nicotine in the body. Dopamine is related to our addiction, motivation and reward responses. When Nicotine enters the bloodstream and passes through the blood-brain barrier, it activates the release of the dopamine hormone. When this hormone is increased, the body goes into fight or flight response and gives smokers a ‘high’. (Polito, 2013) Nicotine has to pass through the blood-brain barrier. For those who don’t know the blood-brain barrier is a filter that controls the blood flowing into the CNS. “The membranes between the blood and brain have effectively no pores. This will prevent many polar materials (often toxic materials) from entering the brain. However, smaller lipid materials or lipid soluble materials can easily enter the brain.” (Bourne, 2010)
Nicotine does not follow our common polarity rules, such as like dissolves like, because it is both polar and nonpolar; this mean it can dissolve in both water and nonpolar solvents. Now I know you’re all curious as to why that is. Well, Nicotine’s structural formula is 50% polar and 50% nonpolar. I’ll just draw it up on the board quickly. (Wikipedia, 2013)
Let’s start with this bond here.
Now this isn’t a normal benzene ring as a carbon to hydrogen bond has been replaced with a nitrogen. The chemical formula now becomes C5H5N. This has a huge impact on the polarity of this section. I’m just going to draw up the electronegativity values of the atoms we’re concerned with. So carbon has a value of 2.55, hydrogen with 2.2 and nitrogen with 3.04. Carbon to hydrogen bonds are nonpolar because the electronegativity difference is 0.35 when 2.55 is taken away from 2.2. A carbon to nitrogen bond highly favours nitrogen that is polar because of its electronegativity value. Therefore, it can be concluded that this half of the molecule is polar. The next section again has a carbon to nitrogen bond that is polar. However, it has three nonpolar sections around it. Carbon to carbon bonds are nonpolar because there is a 0 difference in electronegativty. Carbon to hydrogen are nonpolar as explained before. Therefore, it can be concluded that this half of the molecule is nonpolar.
It’s not like Nicotine needs any further help passing through the blood-brain barrier because of its polarity but it also has very small molecules that enable the molecules to more easily enter the blood-brain barrier. Once through the blood-brain barrier, Nicotine binds with the nicotinic acetylcholine receptors.
Now, nicotinic agonist’s can either be α4β2 or α7 receptor agonists. Nicotine is a α4β2 receptor agonist. What does this mean? Well as seen in this diagram,
receptors are categorized into heteromeric, with multiple subunits, and homomeric, with one subunit. The heteromeric receptors contain two α4 subunits and three β2 subunits. As seen here that means that acetylcholine can bond twice. (Wikipedia, 2013)
So Nicotine has passed through the blood-brain barrier in the CNS or entered the adrenal medulla in the kidney. Now, for the NCR’s pores to be opened both bonding sites must be occupied for activation to occur; nicotine is the molecule required to bind them. The acetylcholine areas contain an A, B and C loop for the α subunit and D, E and F for the β subunit. Nicotine chemically binds at the two binding sites and opens the pores. Once opened, the pore is stabilized and desensitized to Nicotine and then “allows positively charged ions to move across it; in particular, sodium and calcium enters the cell and potassium exits.” (Wikipedia, 2013) (Wikipedia, 2013)
The release of calcium releases neurotransmitters that then bonds with the receptors, which are responsible for releasing more dopamine into the body. This further increases the ‘high’ felt by smoking addicts. When Nicotine is removed from the body, the body immediately goes through withdrawal symptoms as Nicotine addiction is both psychological and physical as I mentioned before. When you stop smoking, your body will kick into an ‘I need Nicotine to live’ drive because your brain will now have a physical dependence on Nicotine; it believes that it needs Nicotine for the receptors and neurotransmitters to function correctly. Once your body releases it no longer has Nicotine in its system, which is psychological and occurs very quickly after the last ‘hit’ of Nicotine, your body will begin to freak out and start having withdrawals; that’s why smoking is so hard to stop.
Bibliography:
American Heart Association. (2013) Why is it so hard to quit? http://www.heart.org/HEARTORG/GettingHealthy/QuitSmoking/QuittingSmoking/Why-is-it-so-hard-to-quit_UCM_324053_Article.jsp
Balkin, Karen F. (2005) Tobacco and Smoking. United States of America: Greenhaven Press.
Burchfield, Geoffrey. (1997) Nicotine. http://www.abc.net.au/quantum/poison/nicotine/nicotine.htm
Have to Quit Smoking. (2013) What are the ingredients in Cigarettes? http://www.havetoquitsmoking.com/
Healey, Justin. (2013) Drugs and Addiction. Australia: Spinney Press.
Martin, Terry. (2013) Blood-brain Barrier. http://quitsmoking.about.com/od/glossaryofterms/g/bloodbrainbarrier.htm
Polito, John R. (2013) What is nicotine addiction? http://whyquit.com/whyquit/linksaaddiction.html
Sanders, Pete; Myers, Steve. (2004)Taking Drugs. London: Aladdin Books Ltd.
Scott. (2013) Why is Nicotine addictive? http://www.todayifoundout.com/index.php/2013/07/why-is-nicotine-addictive/
Wikipedia. (2013) Neurotransmitters. http://en.wikipedia.org/wiki/Neurotransmitters
Wikipedia. (2013) Nicotinic Receptor. http://en.wikipedia.org/wiki/Nicotinic_receptor
Wikipedia. (2013) Nicotinic Agonist. http://en.wikipedia.org/wiki/Nicotinic_agonist
Wikipedia. (2013) Partial Agonist. http://en.wikipedia.org/wiki/Partial_agonist
An Australian Health Survey conducted in 2011-2012 concluded that 3.1 million Australians are current smokers. (Australian Bureau of Statistics, 2013). This means that 14% of Australia’s population are current smokers compared to more than 40% in the 1980’s – a dramatic decrease with the smoking rate continuing to decline each year. Now there are many factors that can be considered for this drop such as the rise in prices or maybe less accessibility but another big factor is that it’s no longer seen in the same way socially like it was back in the 1980’s. With more and more anti-smoking products being created it decreases the amount of smokers and I’m …show more content…
going to go into more depth about that later on in the presentation.
But firstly, the question on everyone’s lips, why are so many people smoking?
What makes cigarettes so addictive? Well, I’m glad to tell you that’s why I am here today to explain and teach you about for the first half of this presentation. Cigarettes contain over 599 additives; one of those being Nicotine. Nicotine, also known in our chemistry world as 3-[(2S)-1-methylpyrrolidin-2-yl]pyridine – but you don’t have to concern yourself with that name – is the major additive in cigarettes responsible for their addictive qualities. Now if I say so myself, Nicotine is good at its job considering that there is typically only 1mg of Nicotine absorbed into the body per cigarette. Now Nicotine is a dangerous addicting drug because it has both psychological and physical addicting qualities, similar to heroin and cocaine, which makes the addiction that much harder to …show more content…
combat.
So what actually is Nicotine? Well, Nicotine is a parasymphatomimetic alkaloid from the nightshade family of plants called the Solanaceae. A parasymphatomimetic drug is “a drug or poison that acts by stimulating or mimicking the parasympathetic nervous system.” (Dorlands Medical Dictionary, 2013) Nicotine is also a nicotinic agonist. “A nicotinic agonist is a drug that mimics the action of acetylcholine at nicotinic acetylcholine receptors (NCR’s)” (Henningfield, 2006). Nicotine is administered orally. The body reacts as soon as Nicotine enters the body. Nicotine affects two different areas of the body: the adrenal medulla and the central nervous system.
The adrenal medulla is part of the adrenal gland found in the kidney. It has an impact on the body’s energy, heart rate and metabolism as it secretes hormones, such as adrenaline and dopamine. The kidney absorbs the Nicotine through the bloodstream which then enters the adrenal medulla. The Nicotine then binds with the nicotinic receptors which causes adrenaline to be released into the body; this causes common symptoms of smoking such as an increase in heart rate and blood pressure.
Dopamine is a hormone which is influenced by Nicotine in the body. Dopamine is related to our addiction, motivation and reward responses. When Nicotine enters the bloodstream and passes through the blood-brain barrier, it activates the release of the dopamine hormone. When this hormone is increased, the body goes into fight or flight response and gives smokers a ‘high’. (Polito, 2013) Nicotine has to pass through the blood-brain barrier. For those who don’t know the blood-brain barrier is a filter that controls the blood flowing into the CNS. “The membranes between the blood and brain have effectively no pores. This will prevent many polar materials (often toxic materials) from entering the brain. However, smaller lipid materials or lipid soluble materials can easily enter the brain.” (Bourne, 2010)
Nicotine does not follow our common polarity rules, such as like dissolves like, because it is both polar and nonpolar; this mean it can dissolve in both water and nonpolar solvents. Now I know you’re all curious as to why that is. Well, Nicotine’s structural formula is 50% polar and 50% nonpolar. I’ll just draw it up on the board quickly. (Wikipedia, 2013)
Let’s start with this bond here.
Now this isn’t a normal benzene ring as a carbon to hydrogen bond has been replaced with a nitrogen. The chemical formula now becomes C5H5N. This has a huge impact on the polarity of this section. I’m just going to draw up the electronegativity values of the atoms we’re concerned with. So carbon has a value of 2.55, hydrogen with 2.2 and nitrogen with 3.04. Carbon to hydrogen bonds are nonpolar because the electronegativity difference is 0.35 when 2.55 is taken away from 2.2. A carbon to nitrogen bond highly favours nitrogen that is polar because of its electronegativity value. Therefore, it can be concluded that this half of the molecule is polar. The next section again has a carbon to nitrogen bond that is polar. However, it has three nonpolar sections around it. Carbon to carbon bonds are nonpolar because there is a 0 difference in electronegativty. Carbon to hydrogen are nonpolar as explained before. Therefore, it can be concluded that this half of the molecule is nonpolar.
It’s not like Nicotine needs any further help passing through the blood-brain barrier because of its polarity but it also has very small molecules that enable the molecules to more easily enter the blood-brain barrier. Once through the blood-brain barrier, Nicotine binds with the nicotinic acetylcholine receptors.
Now, nicotinic agonist’s can either be α4β2 or α7 receptor agonists. Nicotine is a α4β2 receptor agonist. What does this mean? Well as seen in this diagram,
receptors are categorized into heteromeric, with multiple subunits, and homomeric, with one subunit. The heteromeric receptors contain two α4 subunits and three β2 subunits. As seen here that means that acetylcholine can bond twice. (Wikipedia, 2013)
So Nicotine has passed through the blood-brain barrier in the CNS or entered the adrenal medulla in the kidney. Now, for the NCR’s pores to be opened both bonding sites must be occupied for activation to occur; nicotine is the molecule required to bind them. The acetylcholine areas contain an A, B and C loop for the α subunit and D, E and F for the β subunit. Nicotine chemically binds at the two binding sites and opens the pores. Once opened, the pore is stabilized and desensitized to Nicotine and then “allows positively charged ions to move across it; in particular, sodium and calcium enters the cell and potassium exits.” (Wikipedia, 2013) (Wikipedia, 2013)
The release of calcium releases neurotransmitters that then bonds with the receptors, which are responsible for releasing more dopamine into the body. This further increases the ‘high’ felt by smoking addicts. When Nicotine is removed from the body, the body immediately goes through withdrawal symptoms as Nicotine addiction is both psychological and physical as I mentioned before. When you stop smoking, your body will kick into an ‘I need Nicotine to live’ drive because your brain will now have a physical dependence on Nicotine; it believes that it needs Nicotine for the receptors and neurotransmitters to function correctly. Once your body releases it no longer has Nicotine in its system, which is psychological and occurs very quickly after the last ‘hit’ of Nicotine, your body will begin to freak out and start having withdrawals; that’s why smoking is so hard to stop.
Bibliography:
American Heart Association. (2013) Why is it so hard to quit? http://www.heart.org/HEARTORG/GettingHealthy/QuitSmoking/QuittingSmoking/Why-is-it-so-hard-to-quit_UCM_324053_Article.jsp
Balkin, Karen F. (2005) Tobacco and Smoking. United States of America: Greenhaven Press.
Burchfield, Geoffrey. (1997) Nicotine. http://www.abc.net.au/quantum/poison/nicotine/nicotine.htm
Have to Quit Smoking. (2013) What are the ingredients in Cigarettes? http://www.havetoquitsmoking.com/
Healey, Justin. (2013) Drugs and Addiction. Australia: Spinney Press.
Martin, Terry. (2013) Blood-brain Barrier. http://quitsmoking.about.com/od/glossaryofterms/g/bloodbrainbarrier.htm
Polito, John R. (2013) What is nicotine addiction? http://whyquit.com/whyquit/linksaaddiction.html
Sanders, Pete; Myers, Steve. (2004)Taking Drugs. London: Aladdin Books Ltd.
Scott. (2013) Why is Nicotine addictive? http://www.todayifoundout.com/index.php/2013/07/why-is-nicotine-addictive/
Wikipedia. (2013) Neurotransmitters. http://en.wikipedia.org/wiki/Neurotransmitters
Wikipedia. (2013) Nicotinic Receptor. http://en.wikipedia.org/wiki/Nicotinic_receptor
Wikipedia. (2013) Nicotinic Agonist. http://en.wikipedia.org/wiki/Nicotinic_agonist
Wikipedia. (2013) Partial Agonist. http://en.wikipedia.org/wiki/Partial_agonist