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Is Nicotine a Dangerous Compound to Society?

Authored by Pitor Plaskota


“Is Nicotine a Dangerous Compound to Society?”

The global perception of nicotine in today’s society is very negative due to its presence in tobacco products. The risks of smoking have been clearly outlined by anti-smoking campaigns, government regulation of tobacco products and research relating to smoking.1 2 3 As a result, a certain stigma has arisen around the word nicotine, but is nicotine actually dangerous? The World Health Organisation (WHO) has stated that “the tobacco epidemic is one of the biggest public health threats the world has ever faced”. However, this is not a concern only to those who actively smoke as 10% of the estimated 6 million tobacco-related deaths each year worldwide are due to passive smoking.4 Indeed, these statistics have given rise to the well-known slogan printed on tobacco products in the UK “Smoking kills”. So, if most people today are aware of the adverse effects of smoking, why do they continue to smoke? Nicotine may hold the answer.


What actually is nicotine? Nicotine is a naturally occurring liquid alkaloid with stimulatory effects. Alkaloids are a class of organic compounds containing carbon, hydrogen, oxygen and nitrogen.5 They tend to be extracted from plants and usually have potent effects on the human body. Other notable examples of alkaloids include caffeine, cocaine and quinine. There are a couple of similarities between nicotine and acetylcholine, a neurotransmitter that is important in reward pathways in the brain. This is an important consideration when looking at the mode of action of nicotine.


Figure 1:

Comparison of chemical structures of acetylcholine and nicotine. Blue and red represent the similarities between the molecules. (Produced in ChemDraw)

The mode of action of nicotine is well established. When a person smokes a cigarette, nicotine enters the bloodstream through several mucosal lining entry points - predominantly in the nose, mouth and lungs.5 Once in the blood nicotine is able to cross the blood-brain barrier, just as other stimulants such as heroin do. Upon crossing this barrier its similarity to acetylcholine comes into play, it binds to nicotinic acetylcholine receptors (nAChRs) that usually bind acetylcholine.6 This agonistic effect causes the release of various other neurotransmitters, including the notorious dopamine.



Dopamine stimulates a feeling of pleasure in the body and consequently it is involved in the body’s reward pathway. This information is vital in understanding why people continue to self-administrate nicotine, usually in the form of smoking. While this article is mainly focused on the biochemistry involved in nicotine action it is worth noting that as with most biological processes genetics, age and other factors are involved when talking about processes that are mostly neurological. With long-term exposure to nicotine the nAChRs become desensitised and as a result, the body tries to compensate by increasing the number of receptors.6 7 Consequently, a person must smoke more to achieve the same level of satisfaction, further developing nicotine dependence.


So why is nicotine addiction detrimental? While the compound nicotine itself does not contribute to the well-known cancer risks, these risks do develop from the various carcinogens in tobacco products.8 Additionally, smoking cigarettes increases the concentration of CO in the bloodstream, a very deadly gas that competes with oxygen to bind to haemoglobin. CO binds far more strongly, and as a result reduces the concentration of oxygen in the blood.9 Lack of oxygen can lead to a variety of symptoms including shortness of breath, fatigue, dizziness, headaches and nausea.9 Tar from cigarettes is also inhaled and damages the cilia in the lungs, thus enabling tar and other toxins to enter deeper into the lungs. This is because cilia usually waft out any particles that could enter the lungs.10


To summarise, I believe it can be concluded that nicotine alone poses little risk to the majority of the population, as it is only dangerously toxic in high doses or to children. The largest problem arises from nicotine’s addictive effects, as they encourage people to continue smoking tobacco-related products that significantly increase risk of cancer. Moreover, new products such as e-cigarettes may provide a safer alternative to cigarettes due to their lack of tobacco content, however more research needs to be done on their long-term effects to state this for certain.


References:

[1] Telegraph Article – Australian Smoking Packaging http://www.telegraph.co.uk/news/worldnews/australiaandthepacific/australia/8434576/Australia-unveils-ugly-cigarette-packets-in-fight-against-smoking.html, (Accessed 14/08/2018)

[2] UK Government “The end of Tobacco” https://www.gov.uk/government/news/the-end-of-open-tobacco-displays-5-months-to-go, (Accessed 14/08/2018)

[3] S. P. Saha, D. K. Bhalla, T. F. Whayne, C.G. Gairola, Int J Angiol, 2007, 16, 77-83

[4] World Health Organization, http://www.who.int/mediacentre/factsheets/fs339/en/, (Accessed 12/03/2017)

[5] How Stuff Works – nicotine article http://science.howstuffworks.com/nicotine.htm

(Accessed 14/08/2018)

[6] N. L. Benowitz, N Engl. J Med, 2010, 362, 2295–2303

[7] A. P. Govind , P. Vezina, and W. N. Green, Biochem Pharmacol, 2009, 78, 756–765

[8] NHS, http://www.nhs.uk/news/2015/08August/Pages/E-cigarettes-95-per-cent-less-harmful-than-smoking-says-report.aspx, (Accessed 20/08/2018)

[9] Carbon monoxide kills, http://www.carbonmonoxidekills.com/are-you-at-risk/carbon-monoxide-in-cigarettes/, (Accessed 20/08/2018)

[10] Very well, https://www.verywell.com/tar-in-cigarettes-2824718, (Accessed 20/08/2018)