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What Nicotine Does to Your Body

If you are one of 1.9 million New Yorkers who smoke, you most likely know about nicotine, at least how it feels in your body, and how if feels good. What you may not know is what it does or even what it is.  Sure, it’s a chemical, but more importantly it is an organic chemical. One molecule of nicotine is made of 10 molecules of carbon, 14 molecules of hydrogen and 2 molecules of nitrogen. 

Our bodies, also organic, are very sensitive and react specifically to other organic compounds. There are receptors in our body that respond specifically to nicotine. They’re even called nicotinic receptors, and they are everywhere in our body. Nicotine fits inside of these receptors like a key inside of a lock. These locks are in the autonomic nervous system, between our muscles and the nerves that tell the muscles what to do – the neuromuscular junction, and in our brains. These receptors also bind acetylcholine, which, unlike nicotine, is synthesized by our bodies. Acetylcholine is a neurotransmitter and basically tells your muscles when to move and how to move, so these receptors are wherever you have muscles – everywhere. Therefore, nicotine acts all over the body.

When nicotine acts, it causes adrenaline to be released into your body. Adrenalin works in the “fight or flight” system of the body, a.k.a. the sympathetic nervous system. If you’ve every run after a cab then you know what the “fight or flight” system does.  Your heart beats faster; your blood vessels constrict. Nicotine is a vasoconstrictor, and that’s why your cold fingers feel even colder when you smoke that necessary cigarette in mid-January.  The blood supply to the skin is decreased, drawing heat away from the skin. Adrenaline also tells your body to drop lots of glucose in your blood, a life of hyperglycemia, and tells insulin to “Stop! Don’t take that glucose out of the blood!”. With plenty of glucose in the blood, the body thinks its not hungry, hence cigarettes as appetite suppressors. In addition to all of this excitement, in the long run, nicotine increases the amount of low-density lipoproteins, LDL, commonly known as “bad” lipoproteins, which increases the risk of heart attacks and strokes.

If that’s all that nicotine did to our bodies then we could all just run around to get the physical feeling of adrenaline pumping through our bodies, but nicotine has a field day in the brain. The acetylcholine receptors mentioned previously are located in a pathway in the brain known as the “reward center”. This is the same place that is stimulated when we eat, when we drink, when we have sex. Cocaine works on the same pathway. When nicotine stimulates the neurons in the reward center, the neurons release dopamine. Dopamine reinforces activities that are essential for survival, like eating, sleeping, and now smoking, not that smoking is essential for survival, but dopamine makes us feel that way. Cigarettes are positively reinforced by our brain! That’s why quitting is so hard. 

Release of acetylcholine also causes neurons in other parts of the brain to release glutamate, which is involved in developing memories. One theory says that new memories are created about cigarettes as you smoke them, thereby hardwiring the little suckers and the euphoric feeling they create into your brain.

Don’t be discouraged. Our brains are extremely smart; you can train your brain to behave differently, and essentially rewire the pathways with a little help. For information on behavior therapy and other quitting methods, go to “How to quit”.