Nicotine, an alkaloid derived from the leaves of tobacco plants (Nicotiana tabacum and Nicotiana rustica) is the main additive in tobacco products (1).

The nicotine molecule is chiral; the enantiomer present in nature is S (-). During the combustion of tobacco, a partial racemization takes place; the smoker is therefore also exposed to the R (+) enantiomer. The S (-) enantiomer binds to nicotinic receptors, while the physiologically less active enantiomer R (+) is a cholinergic receptor antagonist (2).

Taken in small doses, nicotine stimulates the release of dopamine.

At high concentrations, nicotine blocks nicotinic acetylcholine receptors, causing paralysis of skeletal muscles, including respiratory ones. This is the reason for its toxicity and its use as an insecticide.

 Nicotine is able to expand the capacity of the so-called "working memory", limiting however some processes related to the choice and the start of the movement in the human brain: this is what emerges from a study carried out by the Institute of bio-images and molecular physiology of the National Research Council (Ibfm-Cnr) of Milan-Segrate (3).

Molecular Formula: C₁₀H₁₄N₂

Molecular Weight : 162.236 g/mol

References_______________________________________

(1) Republished: Nicotine and health. [BMJ. 2014]
DOI:10.1136/dtb.2014.7.0264

(2) Pool, W.F.,Godin C.S., Crooks, P.A.; Nicotine racemization during cigarette smoking; Toxicologist, 1985,5:232

(3) http://salute24.ilsole24ore.com/articles/13987?refresh_ce=1