Nicotine

Nicotine is an organic compound, an alkaloid found naturally throughout the tobacco plant, with a high concentration in the leaves. It constitutes circa 5% of the plant by weight. It is a potent nerve poison and is included in many insecticides. In lower concentrations, the substance is a stimulant and is one of the main factors leading to the addictiveness of tobacco smoking.

Chemical properties

The chemical formula of nicotine is C₁₀H₁₄N₂ and the structure is

This structure is reflected in the official name 3-(2-(N-methylpyrrolidinyl[?]))pyridine.

Nicotine is water soluble and can be extracted by leaving the cut tobacco in a glass of water for 12 hours.

The CAS number of nicotine is 54-11-5.

Effects on the body

In small doses nicotine has a stimulating effect, increasing activity, altertness and memory. Repeat users report a pleasant relaxing effect. It also increases the heart rate and blood pressure and reduces the appetite. In large doses it may cause vomiting and nausea. The LD50 is 50 mg/kg for rats and 3 mg/kg for mice.

Repeat users of nictine become physically addicted. A report by US Surgeon General C. Everett Koop released on May 16, 1988 stated that the addictive properties of nicotine are similar to those of heroin and cocaine. Withdrawal symptoms include irritability, headaches and anxiety. These symptoms may last for months or years, although they peak at around 48-72 hours.

Although the amount of nicotine inhaled with tobacco smoke is quite small (most of the substance is destroyed by the heat) it is still sufficient to cause addiction. The amount of nicotine absorbed by the body from smoking depends on many factors, including the type of tobacco, whether the smoke is inhaled, and whether a filter is used.

As nicotine enters the body, it quickly gets distributed through the bloodstream and can cross the blood-brain barrier. On average it takes about seven seconds for the substance to reach the brain. It acts on the nicotinic acetylcholine receptors. In small concentrations it increases the activity of these receptors, among other things leading to an increased flow of adrenaline, a stimulating hormone. In high doses, nicotine blocks the nicotinic acetylcholine receptor, which is the reason for its toxicity and its effectiveness as an insecticide.

History and name

Nicotine is named after the tobacco plant Nicotiana tabacum which in turn is named after Jean Nicot, who sent tobacco seeds from Portugal to Paris in 1550 and promoted its medicinal use. It was first isolated in 1828; its molecular formula was established in 1843 and it was first synthesized in 1904.