| 19487632 |
Cosgrove KP, Batis J, Bois F, Maciejewski PK, Esterlis I, Kloczynski T, Stiklus S, Krishnan-Sarin S, O'Malley S, Perry E, Tamagnan G, Seibyl JP, Staley JK: beta2-Nicotinic acetylcholine receptor availability during acute and prolonged abstinence from tobacco smoking. Hum Mol Genet. 2009 Aug 1;18(15):2922-7. Epub 2009 May 9.
CONTEXT: Available levels of nicotinic acetylcholine receptors containing the beta (2) subunit (beta (2)*-nAChR) are higher in recently abstinent tobacco smokers compared with participants who never smoked. Variations in beta (2)*-nAChR availability during the course of abstinence may be related to the urge to smoke, the extent of nicotine withdrawal, and successful abstinence. OBJECTIVE: To examine changes in beta (2)*-nAChR availability during acute and prolonged abstinence from tobacco smoking and to determine how changes in beta (2)*-nAChR availability were related to clinical features of tobacco smoking. DESIGN: Tobacco smokers participated in up to 4 iodide 123-labeled 5-iodo-A-85380 ([(123) I] 5-IA) single-photon emission computed tomography (SPECT) scans during abstinence at 1 day (n = 7) and 1 (n = 17), 2 (n = 7), 4 (n = 11), and 6 to 12 (n = 6) weeks. Age-matched nonsmokers participated in a single [(123) I] 5-IA SPECT scan. All participants completed 1 magnetic resonance imaging study. SETTING: Academic imaging center. PARTICIPANTS: Tobacco smokers (n = 19) and an age-matched nonsmoker comparison group (n = 20). Main Outcome Measure The [(123) I] 5-IA SPECT images were converted to distribution volume and were analyzed using regions of interest. RESULTS: Compared with nonsmokers, beta (2)*-nAChR availability in the striatum, cortex, and cerebellum of smokers was not different at 1 day of abstinence, was significantly higher at 1 week of abstinence, and was not different at 4 or at 6 to 12 weeks of abstinence. In smokers, beta (2)*-nAChR availability was significantly lower in the cortex and cerebellum at 6 to 12 weeks compared with 1 week of abstinence. In addition, cerebellar beta (2)*-nAChR availability at 4 weeks of abstinence was positively correlated with craving on the day of the SPECT scan. CONCLUSIONS: These data suggest that higher beta (2)*-nAChR availability persists up to 1 month of abstinence and normalizes to nonsmoker levels by 6 to 12 weeks of abstinence from tobacco smoking. These marked and persistent changes in beta (2)*-nAChR availability may contribute to difficulties with tobacco cessation. |
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