Smoking upregulates α4β2* nicotinic acetylcholine receptors in the human brain

The role of the α4β2* nicotinic acetylcholine receptors (nAChR) in tobacco addiction in humans is largely unresolved. We visualized brain α4β2* nicotinic acetylcholine receptors of smokers and non-smokers with positron emission tomography using 2-[18F]fluoro-3-(2(S)azetidinylmethoxy)pyridine, commonly known as 2-[18F]F-A-85380. The total brain distribution volume of 2-[18F]F-A-85380 was significantly increased in smokers. Statistical parametric mapping revealed that the most prominent regional differences of distribution volumes (DV) were found in cerebellum and brainstem with an increased uptake in smokers. The up-regulation of α4β2* nAChR upon chronic nicotine exposure via tobacco smoking incorporates subcortical brain regions which may play an important role in nicotine addiction.