A review of smoking behavior and smokers evidence (chemical modification, inducing nicotine metbolism, and individual variations by genotype: dopaminergic function and personality traits)

Abstract

The nicotine metabolism of CYP2A6 (CYP2A6*1A,*1B, and *1C), and the cholecystokinin (CCK; which ­modulates the release of dopamine) and CCK-A receptor gene and personality traits for NEO-FFI, was ­investigated for the mechanism for elucidation of the smoking behavior in Japanese populations. The frequency of the CYP2A6*4C allele, which is a whole deleted allele of the human CYP2A6 gene, was higher, whereas that of CYP2A6*1A/*1B heterozygotes with higher nicotine metabolism activity was lower in nonsmokers than in smokers. There was also a significant difference between the current smoking and nonsmoking groups in the allele frequency of the CCK –45C/T polymorphism. It was also shown that the Openness (O) factor for smokers was significantly higher than that of nonsmokers; however, there were no significant differences in the Neuroticism (N), Extraversion (E), Agreeable (A), and Conscientiousness (C) scores among smokers than nonsmokers. It was suggested that the CYP2A6*4C allele may prevent the carrier from ­smoking, and being a CYP2A6*1A/*1B heterozygote and the CCK T allele may be risk factors for developing smoking behavior. Also, it is possible that persons with a low score in Openness may be refraining from smoking because they have a general negative impression toward smoking.

Keywords::

• Smoking behavior
• nicotine metabolism
• CYP2A6*4C
• CCK
• CCK-A receptor
• dopamine

Acknowledgments

This research was subsidized by the Ministry of Health, Labor, and Welfare’s Research Fund on “Development of a Tailor-made Pain Remedial Method by Inspection Gene Polymorphism” (H17-Pharmacogenomics 001) and the Promotion and Mutual Aid Corporation for Private Schools of Japan, Grant-in-Aid for Matching Fund Subsidy for Private Universities.

Declaration of interest: There are no financial conflicts of interest.