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"But I threw it easily!"

While doctors can only estimate approximately, the level of dependence in comparison with other people will be increased or decreased. In modern commercial tests, only one single gene is often tested - one for which the link with nicotine dependence is firmly established and well understood.
This gene is called CHRNA3. It determines the structure of the alpha-3 subunit, one of the proteins in the nicotinic acetylcholine receptor. In the gene there is a site rs1051730, in which people often have a mutation - the replacement of one of the letters of the genetic code (normally there should be a cytosine at this place, and with a mutation it changes to thymine). This replacement is devoted to hundreds of studies conducted on tens of thousands of participants, and everywhere there is an undeniable statistical relationship with the intensity of nicotine addiction. This is extremely mysterious, because in fact this specific nucleotide replacement in this area can not affect the amino acid sequence of the protein and, accordingly, its structure and operability. Maybe it somehow changes the stacking of RNA, making the production of proteins less effective. And it is possible that this nucleotide substitution was accidentally discovered first, but in fact it is associated with some other mutation, yet changing the activity of the receptor (if the previous few sentences sounded monstrous, but you still want to understand, then I remind you that in the end of the book is a biological crib). As for the gene CHRNA3, then in any case, continue to study, because the statistical relationship of its mutations and dependencies is not in anyone's doubt.
In 2012, scientists from the University of Copenhagen published a study in which the CHRNA3 gene was examined already in 57 657 people (34 592 of whom have ever smoked). They found that 11% of Danish residents had two mutant copies of the CHRNA3 gene (that is, they had inherited them from both mother and father), 44% had heterozygotes, that is, carriers of the same mutant and one standard variant, and the remaining 45% had two normal copies of the gene. It turned out that smoking is about the same frequency found in all groups, but people with mutations in the gene CHRNA3 smoked significantly more cigarettes, and when trying to quit smoking they needed nicotine replacement therapy more often and longer than people with the usual genotype. They are also more likely to develop chronic obstructive pulmonary disease, as well as lung cancer, but this apparently directly follows simply from a higher intensity of smoking, because there is no nonspecific connection between this gene and lung diseases.
In addition to the gene CHRNA3, which for some reason was the most fashionable topic for research, there are, of course, other genes associated with the development of nicotine addiction. Another fragment of the acetylcholine receptor, the alpha-5 subunit, is encoded, as you might guess, by the CHRNA5 gene. There is a mutation in which amino acid No. 398 in the protein changes: instead of aspartic acid present in all animals, some people in this place appear asparagine. This mutation seems to have originated in Europe, because there its prevalence reaches 37%, and in Africans, Asians and American Indians it practically does not occur. Experiments on cell cultures have shown that a mutation worsens the functioning of the receptor - which may mean that people become particularly susceptible to the ability to spur its work with nicotine. Indeed, 43% of the carriers of this mutation report in the polls that the first cigarette in life caused an intense buzz and emotional upsurge. Among smokers with the usual version of this gene, the first cigarette was so popular with only 10%.
Magnetic resonance tomography also shows differences between smokers with different variants of the CHRNA5 gene, and the mutation is associated with a smaller burst of excitation at the sight of a photograph of a smoking person (perhaps cigarettes affect smokers with a mutation less so, and this prompts them to smoke again and again? ).
There are several tens of genes for which a more or less pronounced statistical relationship with smoking has been established. In addition to genes encoding acetylcholine receptors, the genes of enzymes responsible for the speed of processing of nicotine and the many genes associated with the work of dopamine and serotonin in the brain contribute to the formation of the dependence. Many of these genes are associated with several addictions, such as alcohol and nicotine.
Very simplifying and coarsening, we can say that in our brain there are metabolic pathways necessary to experience a sense of pleasure. If a person they all work well, then, in general, it is not necessary to smoke (although many still begin and sit down). But if a person has any mutations that reduce the ability of his brain to experience a sense of pleasure, then the first random teenage cigarette produces a completely overwhelming impression on him, because it spurs the work of the necessary receptors and activates the reward system to unprecedented heights. Of course, I want to repeat this experience again and again. But, alas, with constant smoking, the system does not work that way, because the sensitivity of acetylcholine receptors gradually decreases. As a result, a person gets into a terrible vicious circle in which he smokes more and more to avoid being unhappy, and the receptors become less sensitive to nicotine (and to their own acetylcholine at the same time), and one has to smoke even more, and the sensitivity is still decreasing, and it's getting harder to stop.
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"But I threw it easily!"

  1. My daughter is four and a half years old, and I have been married for eight years. I would like to know how to establish a relationship with an alcoholic husband who has been abstaining from alcohol for a year and three months.
    The most effective means is communication. You must learn to talk to your husband without complaining about fate, not blaming him for anything and not trying to change it. How can this be learned? Tell him about your feelings frankly, without concealment, remaining natural. Tell him, for example, about what you experienced in the past, what you are experiencing now: about your hopes, fears, fears, observations,
  2. Quitting smoking is easy, or false gain
    Here everything is the other way round - the final part of the statement in the form confirms the initial, and in fact - refutes, destroys it. For example - Mark Twain's well-known joke: Quitting smoking is easy. I threw fifty times. G. Heine, answering the question, is Mrs. N. beautiful, said: She looks like Venus of Milos: just as old and as toothless. JC Jerome has such a comic phrase:
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  4. My husband was the youngest child in the family and before our acquaintance lived with his mother. When he was just a child, their father abandoned his family.
    Now his mother does not accept me and reproaches me for everything, even sometimes calls me a liar and ill-bred. I understand that my husband can not but visit my mother, but I can not agree with his demand to visit and respect her too. What should I do? From what you have said, it follows that your spouse and mother-in-law suffer from an oedipal complex. Their relations are built more like a "man-woman" type, than by type
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    But I still can not understand why I need such a life. Could you, as an experienced and knowledgeable person, advise me how to experience love and joy in such a situation? I love this man and I'm almost happy with him. Is this my karma or chose this path myself? Thanks to the path chosen by you, you begin to comprehend the art of love. The goal of each person is the improvement of the inner world, and
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