Nicotine actually exerts its effect by mimicking a second neurotransmitter called acetylcholine.

ECONOMIST: Great drug, shame about the delivery system | The

Interest has thus focused on drugs that inhibit the breakdown of acetylcholine, and also on nicotine, which works by mimicking its effect.

ECONOMIST: Cognitive enhancement

And the effect on the brain is different: with nicotine, the more you smoke, the more you want.

ECONOMIST: Chilies

E-cigarettes work by vaporising nicotine-laced liquid that can be inhaled, replicating the effect of smoking without all of the carcinogens.

CNN: Sales of e-cigarettes continue to soar