Tried quitting smoking a number of times but failed at each of those attempts? A recently done study on mice might have some clue to this. Scientists have revealed that the problem lies in a gene within the brain that constantly craves for more nicotine and thus it becomes impossible for you to quit.

The study comes from the researchers of the Scripps Research Institute in Florida and the University of Colorado in the USA. It was funded by the National Institute on Drug abuse and the James and Esther king Biomedical Research Programme at the Florida Department of Health and was published in the medical journal Nature.

Nicotine, a major component of cigarettes, has the ability to bind to some of the receptors in the nerve cells. This leads to the typical feeling one has on smoking such as heightened activity, improved reaction time, a sense of satisfaction and achievement. The receptors that nicotine can bind to are called nicotinic acetylcholine receptors(nAChRs), made up of five subunits.

Normal rats and mice and genetically modified ones were a part of this study. The genetically modified rats and mice did not have the gene responsible for the formation of the five subunit that form an important part of the nicotine receptors. These mice were exposed to nicotine and their behavior on seeking out nicotine was observed using a number of scientific methods over a period of time.

On the completion of the research the scientists found that normal mice moderated their intake of nicotine while the genetically modified ones took the substance in greater quantities. The mutant mice also appeared to be more motivated to seek and obtain nicotine at high doses. In simple words genetically modified mice had a reduced ability to regulate their intake of nicotine specially at higher doses. A similar behavior, higher vulnerability to tobacco addiction, is reflected in case of humans who smoke often. It was also found that mutated mice were relatively insensitive to the inhibitory effects of nicotine on the reward pathways.

These findings are of great interest and importance but it is still in its preliminary stage. The study holds great potential in understanding the high incidence of lung cancer and COPD in individuals who have variations in the gene responsible for the functioning of nicotine receptors.

However, it would be too hasty a step to say that the behavior would be exactly similar in case of humans. Only after the theory has been tested on humans can we believe that the gene might have a role in the unstoppable addiction to nicotine. Also it is highly unlikely that mutation in a single gene is the reason why some individuals are addicted to nicotine. The human behavior is highly complex and there are biological, environmental , social and emotional factors which can also have an impact on the human behavior which is absent in case of animals. Therefore, only after further research has been done can we completely put the blame on our wrongly wired brains.