美國(guó)科學(xué)家經(jīng)過(guò)研究發(fā)現(xiàn),，吸煙成癮主要是遺傳基因使然，這一發(fā)現(xiàn)將有助于幫助開(kāi)發(fā)戒煙藥品,。
美國(guó)密歇根大學(xué)醫(yī)學(xué)教育系的研究人員稱(chēng)已經(jīng)找到一種基因,，它通常會(huì)讓那些首次嘗試抽煙的人產(chǎn)生一種“飄飄然的感覺(jué)”,， 從而使人很易上癮,，而且這種基因有可能增加吸煙者患肺癌的可能性。來(lái)自美國(guó)密歇根大學(xué)醫(yī)學(xué)教育系的帕莫洛（Ovide Pomerleau）是該研究項(xiàng)目的主要負(fù)責(zé)人,，他已經(jīng)將這一項(xiàng)研究成果發(fā)表在最新一期的《上癮》（Addiction）雜志上,。
帕莫洛和他的研究小組對(duì)435對(duì)志愿者進(jìn)行了跟蹤研究。這些志愿者中有一些從沒(méi)有吸過(guò)煙,，有的曾經(jīng)嘗試過(guò)幾次但是沒(méi)有上癮,。研究結(jié)果發(fā)現(xiàn),，人們?nèi)菀孜鼰熒习a六成是因?yàn)檫z傳基因，兩成基于家庭環(huán)境,，而剩下兩成則緣于個(gè)人經(jīng)歷,。
容易導(dǎo)致人吸煙成癮的基因名叫CHRNA5基因，研究發(fā)現(xiàn),，CHRNA5基因會(huì)影響機(jī)體對(duì)尼古丁的吸收,。帕莫洛的研究小組對(duì)白鼠進(jìn)行實(shí)驗(yàn)發(fā)現(xiàn)，CHRNA5基因會(huì)進(jìn)行變異,，帶有變異基因的實(shí)驗(yàn)鼠所吸收的尼古丁量明顯高于正常實(shí)驗(yàn)鼠,。 此外，CHRNA5基因還會(huì)參與乙酰膽堿（Acetylcholine）受體蛋白的合成,，而乙酰膽堿是產(chǎn)生欣快感的主要神經(jīng)傳導(dǎo)物質(zhì),，它同時(shí)也影響機(jī)體的學(xué)習(xí)與記憶能力、睡眠,、肌肉運(yùn)動(dòng),、心跳和血壓等。 研究人員認(rèn)為,，尼古丁的構(gòu)成與乙酰膽堿高度相似,，很可能與相同的受體蛋白結(jié)合發(fā)生作用，神經(jīng)系統(tǒng)在吸收尼古丁后,，也會(huì)產(chǎn)生和吸收乙酰膽堿相似的欣快感,。帕莫洛說(shuō)，在CHRNA5基因發(fā)生變異之后,，機(jī)體產(chǎn)生的乙酰膽堿受體蛋白更易于和尼古丁結(jié)合,。 對(duì)于實(shí)驗(yàn)鼠，這會(huì)促使機(jī)體吸收更多的尼古丁而不對(duì)神經(jīng)系統(tǒng)產(chǎn)生副作用,；對(duì)于人類(lèi),，這會(huì)使人體易于對(duì)尼古丁產(chǎn)生依賴(lài)性，也就是煙癮,。帕莫洛說(shuō),，分析與煙癮相關(guān)的基因，可以增加對(duì)煙癮機(jī)理的了解,，也有利于針對(duì)不同的基因類(lèi)型設(shè)計(jì)更有效的戒煙療法,。這一發(fā)現(xiàn)還可以用來(lái)幫助開(kāi)發(fā)戒煙藥品。（生物谷Bioon.com）
生物谷推薦原始出處：
Addiction,，Volume 103 Issue 9, Pages 1544 - 1552,，Richard Sherva，Ovide F. Pomerleau
Association of a single nucleotide polymorphism in neuronal acetylcholine receptor subunit alpha 5 (CHRNA5) with smoking status and with 'pleasurable buzz' during early experimentation with smoking
Richard Sherva 1 , Kirk Wilhelmsen 2 , Cynthia S. Pomerleau 3 , Scott A. Chasse 4 , John P. Rice 1 , Sandy M. Snedecor 3 , Laura J. Bierut 1 , Rosalind J. Neuman 1 & Ovide F. Pomerleau 3
1 Department of Psychiatry, Washington University School of Medicine, St Louis, MO, USA, 2 Department of Genetics and Neurology, Carolina Center for Genome Sciences, Chapel Hill, NC, USA, 3 Department of Psychiatry, University of Michigan, Ann Arbor, MI, USA and 4 Department of Biochemistry and Biophysics, University of North Carolina, Chapel Hill, NC, USA
Correspondence to Ovide Pomerleau, University of Michigan Department of Psychiatry, Room 2137, Rachel Upjohn Building, Ann Arbor, MI 48109-5765, USA. E-mail [email protected]
Re-use of this article is permitted in accordance with the Creative Commons Deed, Attribution 2.5, which does not permit commercial exploitation.
ABSTRACT
Aims To extend the previously identified association between a single nucleotide polymorphism (SNP) in neuronal acetylcholine receptor subunit alpha-5 (CHRNA5) and nicotine dependence to current smoking and initial smoking-experience phenotypes.
Design, setting, participants Case–control association study with a community-based sample, comprising 363 Caucasians and 72 African Americans (203 cases, 232 controls).
Measurements Cases had smoked ≥ five cigarettes/day for ≥ 5 years and had smoked at their current rate for the past 6 months. Controls had smoked between one and 100 cigarettes in their life-time, but never regularly. Participants also rated, retrospectively, pleasurable and displeasurable sensations experienced when they first smoked. We tested for associations between smoking phenotypes and the top 25 SNPs tested for association with nicotine dependence in a previous study.
Findings A non-synonymous coding SNP in CHRNA5, rs16969968, was associated with case status [odds ratio (OR) = 1.5, P = 0.01] and, in Caucasians, with experiencing a pleasurable rush or buzz during the first cigarette (OR = 1.6, P = 0.01); these sensations were associated highly with current smoking (OR = 8.2, P = 0.0001).
Conclusions We replicated the observation that the minor allele of rs16969968 affects smoking behavior, and extended these findings to sensitivity to smoking effects upon experimentation. While the ability to test genetic associations was limited by sample size, the polymorphism in the CHRNA5 subunit was shown to be associated significantly with enhanced pleasurable responses to initial cigarettes in regular smokers in an a priori test. The findings suggest that phenotypes related to subjective experiences upon smoking experimentation may mediate the development of nicotine dependence.
