People who are addicted to smoking cigarettes often say there is no cigarette like the first cigarette of the day. While one may chalk that line up to a clich??, there is much truth to that sentiment. In fact, the reason why smokers are ???right??????that the first smoke of the day is the best smoke of the day???has a basis in neuropharmacology.

Regardless of how and when it happens, the chemistry in the brain affects a person???s addiction to smoking. One of active ingredients in a cigarette is nicotine. Like many other drugs, such as cocaine or heroin, a person builds a tolerance to the effects of nicotine upon repeated exposure. Once a cigarette is inhaled, the nicotine is carried into the lungs. From the lungs it rapidly enters the circulatory system and is carried throughout the body in the bloodstream. When it gets to the brain, it rapidly crosses the blood brain barrier and binds to specific receptors. The result of binding to these receptors facilitates the release of neurotransmitters. Some neurotransmitters that are released are related to ???pleasure,??? such as dopamine. Neurotransmitters, such as dopamine, can act as reinforcement and increase the desire for more cigarettes.

Understanding the mechanism of action of nicotine doesn???t explain why that first cigarette is judged ???best.??? The reason it is ???best??? has to do with the length of time nicotine remains bound to the receptors. Over the course of the day, smokers likely have more than one cigarette (partial tolerance occurs upon successive smoking). However, during the hours they sleep, there are no cigarettes. Thus, the nicotine can ???wash??? out of the body. Upon waking, the smoker???s receptors are ???empty,??? and there is an intense craving to be filled. That first cigarette a smoker has satisfies that craving and starts the vicious smoking cycle (and tolerance) once again.