Chemistry of Nicotine

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Date Submitted: March 17, 2010

Tobacco has a long history and has had a significant impact since first introduced to Western society in the 16th century. There is evidence that Native Americans were using tobacco long before the 16th century. They smoked through a pipe for special religious and medical purposes but the worldwide spread of tobacco was initiated as a result of European discovery by Spanish, Portuguese and French explorers.(1,2) Christopher Columbus testified to the widescale use of tobacco by Native Americans but Jacques Cartier stands as the first known explorer to experiment with tobacco.(2) By the time the Europeans settled in North America, tobacco had become the most important crop providing colonies with a primary export and source of income.(3) Approximately 0.6-3.0% of dry weight of tobacco consists of the alkaloid, Nicotine, originating from the Solanaceae family of plants.(4,5) It is found in the tobacco leaves as biosynthesis takes place in the roots. The name Nicotine is derived from the tobacco plant, Nicotiana tabacum, which was named after Jean Nicot, a French ambassador who sent tobacco seeds from Portugal to Paris in 1550 and promoted its medicinal use.(4,6) In 1828 two German chemists Posselt and Reinmann were the first to isolate Nicotine from the tobacco plant and considered it as a poison. In 1843, Melsens described its chemical empirical formula and the first synthesis was done in 1904 by A. Pictet and Crepieux.(4) As colonialism spread all over the world and as tobacco farming became more and more profitable, the image of smoking began to change. By the mid 1800's, cigarette smoking became socially acceptable but truly increased in the 1880's when James Bonsack invented the cigarette-making machine with the ability to produce 120,000 cigarettes a day.(3) As one can imagine, this caused tremendous growth in the tobacco industry open until the 20th century where health consequences due to smoking became public knowledge.(1) Addictive Properties of Nicotine

There are many definitions for what is considered to be addicting but although these definitions are not identical, they have several criteria in common for establishing a drug as addictive. The central element in all forms of drug addiction is that the user’s behavior is largely controlled by a psychoactive substance.(7) Nicotine is proven to be the psychoactive substance in tobacco. Nicotine has different mood-altering effects and is considered to be both a stimulant and a relaxant. User reports show feelings of calmness, relaxation, sharpness and alertness. In some cases smokers may lose weight by reducing their appetites and raising metabolism. All of these outcomes are directly related to nicotine's effect on the brain.(7) When a cigarette is smoked, nicotine travels through the bloodstream from the lungs to the brain and stimulates the release of many neurotransmitters that are largely responsible for most of nicotine's effects.(7) The more important being acetylcholine and dopamine. Enhanced concentration, memory, alertness as well as a reduction of pain are all due to an increase in acetylcholine.(8) Nicotine also extends the duration of positive effects of dopamine and increases sensitivity in brain reward systems.(7,8) Dopamine is one of the more important neurotransmitters actively involved in the brain and with increasing levels, research shows that nicotine acts as a chemical with intense addictive qualities.(7) Nicotine's addictive effect relates to its ability to trigger the release of dopamine in the brain which is associated with the feelings of pleasure.(7) More simply, the use of nicotine causes changes in the brain that make people want to use more and more of the drug. Nicotine in the Cigarette Smoke

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