31 January 2008

Nicotine addiction genes

In the United States alone, smoking causes approximately 400,000 deaths per year. Despite the general awareness about the dangers of smoking, one in eight American adults smokes more than a pack of cigarettes a day. At the same time, smoking is the most preventable of the causes of illness, disability and death.

Over the past few decades, the relationship between nicotine addiction and hereditary factors has been shown in many studies around the world. According to experts, genetics determines the probability of developing nicotine addiction by about 2/3. Knowing the specific culprits of smoking cravings would help develop new, more effective drugs for those who are trying to quit smoking, but it has not been possible to find among the many suspected genes several of the most important ones so far.

The first two "nicotine addiction genes" were discovered as a result of a study conducted by an international group of scientists on a sample of 14,000 people from the United States and Europe.

At the first stage, scientists analyzed DNA samples of about 6,000 people – non-smokers and heavy smokers, comparing about half a million (!) known variants of the structure of the suspected genes. 

At the second stage, the preliminary results obtained were refined by analyzing the selected alleles in another sample of about 8000 people.

The researchers considered certain variants of the genes of two membrane proteins of nerve cells – alpha-3 and alpha-5 subunits of the nicotine receptor to be the "smoking genes" most correlated with increased cravings for nicotine. Now pharmacologists know the targets for new-generation anti-nicotine drugs.

The results of the study are published in the journal Molecular Psychiatry (Berrettini et al., Alpha-5/Alpha-3 Nicotinic Receptor Subunit Alleles Increase Risk for Heavy Smoking).

Portal "Eternal youth" www.vechnayamolodost.ru based on EurekAlert materials

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