一个设计用于更好地理解为什么吸烟者对于香烟如此上瘾的研究发现，尼古丁依赖无法仅仅通过成瘾的吸烟者的大脑和肺的尼古丁更快速积累加以解释。Jed Rose及其同事利用正电子发射断层成像技术（PET）比较了13位成瘾吸烟者和10位没有成瘾的吸烟者的肺和大脑的尼古丁积累。
此前一个被称为Russell的“high nicotine boli”的假说提出，大脑的尼古丁浓度在每吸一口香烟后都会达到峰值，而这些峰值可能与成瘾有关。这次的研究没有发现这种峰值。相反，这组科学家证明了尼古丁在大脑中稳步积累，而且在这两组吸烟者吸完一整根烟之后在大脑达到了峰值。这组作者报告说，成瘾吸烟者比非成瘾吸烟者的大脑中的积累更加缓慢，这部分是由于尼古丁从成瘾吸烟者的肺冲刷出去并进入血液的效率更低。 这组科学家提出，成瘾吸烟者通过吸入更大体积的烟从而补偿更缓慢的尼古丁积累。
这项研究可能有助于为试图戒烟的吸烟者提供一种治疗计划。（生物谷Bioon.com）
相关研究：
Nature：尼古丁受体研究取得新进展
Neuron：尼古丁哄骗大脑产生积极记忆
Nature：查明尼古丁上瘾原因
生物谷推荐原始出处：
PNAS March 8, 2010, doi: 10.1073/pnas.0909184107
Kinetics of brain nicotine accumulation in dependent and nondependent smokers assessed with PET and cigarettes containing 11C-nicotine
Jed E. Rosea,1, Alexey G. Mukhina, Stephen J. Lokitza,b, Timothy G. Turkingtonb, Joseph Herskovica, Frederique M. Behmb, Sudha Gargc, and Pradeep K. Gargc
aCenter for Nicotine and Smoking Cessation Research and
bDepartment of Radiology, Duke University Medical Center, Durham, NC 27705; and
cDepartment of Radiologic Sciences, Wake Forest University Baptist Medical Center, Winston-Salem, NC 27157
Tobacco smoking is a chronic, relapsing disorder that constitutes one of the primary preventable causes of death in developed countries. Two of the popular hypotheses to explain the development and maintenance of strong nicotine dependence in cigarette smokers posit (i) a rapid brain nicotine accumulation during cigarette smoking and/or (ii) puff-associated spikes in brain nicotine concentration. To address these hypotheses, we investigated the dynamics of nicotine accumulation in the smoker's brain during actual cigarette smoking using PET with 3-s temporal resolution and 11C-nicotine loaded into cigarettes. The results of the study, performed in 13 dependent smokers (DS) and 10 nondependent smokers (NDS), suggest that puff-associated spikes in the brain nicotine concentration do not occur during habitual cigarette smoking. Despite the presence of a puff-associated oscillation in the rate of nicotine accumulation, brain nicotine concentration gradually increases during cigarette smoking. The results further suggest that DS have a slower process of brain nicotine accumulation than NDS because they have slower nicotine washout from the lungs and that DS have a tendency to compensate for their slower rate of brain nicotine accumulation compared with NDS by inhaling a larger volume of smoke. For these reasons, smokers’ dependence on cigarette smoking, or the resistance of NDS to becoming dependent, cannot be explained solely by a faster brain nicotine accumulation.
