What is nicotine?Columbus brought tobacco back to Europe from America in the late fifteenth century. When tobacco smoke is inhaled, nicotine is absorbed through the lungs, and reaches the brain in about 7 seconds. Nicotine works by mimicking the actions of a naturally occurring brain chemical, acetylcholine, by docking with its special receptor molecules. Some of these nicotine receptors in the brain activate part of the 'pleasure centre', which could be responsible for nicotine's euphoric effects.
Why is nicotine addictive?
Nicotine is addictive – 9 out of 10 smokers say they would like to stop but can't. Nicotine withdrawal symptoms include irritability, anxiety, loss of concentration and sleeplessness. Cigarette smoke contains a cocktail of other harmful substances, including carbon monoxide and tar. Smoking causes heart and lung diseases as well as a quarter of all cancer deaths in the UK.
Time to give up?
Nicotine is addictive because the brain starts to rely on nicotine to work properly, becoming less sensitive to its own chemical, acetylcholine. But some people manage to give up smoking with the help of nicotine replacements. Nicotine gums, skin patches, nasal sprays and inhalers all give the body nicotine to ease withdrawal symptoms, but without all the other harmful chemicals found in tobacco smoke. New prescription drugs can reduce the smoker's nicotine craving by binding to nicotine receptors in the brain.