Customize your JAMA Network experience by selecting one or more topics from the list below.
Brody AL, Mandelkern MA, London ED, et al. Cigarette Smoking Saturates Brain α4β2 Nicotinic Acetylcholine Receptors. Arch Gen Psychiatry. 2006;63(8):907–914. doi:10.1001/archpsyc.63.8.907
2-[18F]fluoro-3-(2(S)-azetidinylmethoxy) pyridine (2-F-A-85380, abbreviated as 2-FA) is a recently developed radioligand that allows for visualization of brain α4β2* nicotinic acetylcholine receptors (nAChRs) with positron emission tomography (PET) scanning in humans.
To determine the effect of cigarette smoking on α4β2* nAChR occupancy in tobacco-dependent smokers.
Fourteen 2-FA PET scanning sessions were performed. During the PET scanning sessions, subjects smoked 1 of 5 amounts (none, 1 puff, 3 puffs, 1 full cigarette, or to satiety [2½ to 3 cigarettes]).
Academic brain imaging center.
Eleven tobacco-dependent smokers (paid volunteers).
Main Outcome Measure
Dose-dependent effect of smoking on occupancy of α4β2* nAChRs, as measured with 2-FA and PET in nAChR-rich brain regions.
Smoking 0.13 (1 to 2 puffs) of a cigarette resulted in 50% occupancy of α4β2* nAChRs for 3.1 hours after smoking. Smoking a full cigarette (or more) resulted in more than 88% receptor occupancy and was accompanied by a reduction in cigarette craving. A venous plasma nicotine concentration of 0.87 ng/mL (roughly 1/25th of the level achieved in typical daily smokers) was associated with 50% occupancy of α4β2* nAChRs.
Cigarette smoking in amounts used by typical daily smokers leads to nearly complete occupancy of α4β2* nAChRs, indicating that tobacco-dependent smokers maintain α4β2* nAChR saturation throughout the day. Because prolonged binding of nicotine to α4β2* nAChRs is associated with desensitization of these receptors, the extent of receptor occupancy found herein suggests that smoking may lead to withdrawal alleviation by maintaining nAChRs in the desensitized state.
Create a personal account or sign in to: