Nicotine is a chiral alkaloid that is naturally produced in the nightshade family of plants (most predominantly in tobacco and Duboisia hopwoodii) and is widely used recreationally as a stimulant and anxiolytic. As a pharmaceutical drug, it is used for smoking cessation to relieve withdrawal symptoms. Nicotine acts as a receptor agonist at most nicotinic acetylcholine receptors (nAChRs), except at two nicotinic receptor subunits (nAChRα9 and nAChRα10) where it acts as a receptor antagonist. Nicotine constitutes approximately 0.6–3.0% of the dry weight of tobacco. Nicotine is also present at concentrations of millionths of a percent in the edible family Solanaceae, including potatoes, tomatoes, and eggplants, though sources disagree on whether this has any biological significance to human consumers. It functions as an antiherbivore chemical; consequently, nicotine was widely used as an insecticide in the past[when?], and neonicotinoids, such as imidacloprid, are some of the most effective and widely used insecticides.

This NFT description uses material from the Wikipedia article Nicotine which is released under the CC-BY-SA