SPECT imaging of nicotinic acetylcholine receptors in nonsmoking heavy alcohol drinking individuals

Abstract

Background The high rate of comorbidity of tobacco smoking with alcohol drinking suggests common neural substrates mediate the two addictive disorders. The beta 2*-containing nicotinic acetylcholine receptor (β 2*-nAChR) has recently emerged as a prime candidate because some alpha and beta subunit genes have been linked to alcohol consumption and alcohol use behaviors. We hypothesized that β 2*-nAChR availability would be altered by alcohol in heavy drinking nonsmokers. Methods Eleven heavy drinking (mean age 39.6 ± 12.1 years) and 11 age and sex-matched control (mean age 40.8 ± 14.1 years) nonsmokers were imaged using [ 123I]5-IA-85380 ([ 123I]5-IA) single photon emission computed tomography (SPECT). Heavy alcohol drinkers drank varied amounts of alcohol (70–428/month) to facilitate exploratory linear analyses of the possible effects of alcohol. Results Heavy drinkers consumed on average 9.1 ± 7.3 drinks/occasion; whereas controls drank 1.2 ± 0.9 drinks/occasion. Heavy drinkers were imaged 2.0 ± 1.6 days after last alcoholic beverage. Overall, there were no significant differences in β 2*-nAChR availability between the heavy drinking and control nonsmokers. Exploratory analyses of other factors that may be uniquely regulated by alcohol suggested no effects of age, number of alcohol drinks, years drinking, severity of drinking, craving or withdrawal. Conclusions These preliminary analyses do not suggest a decrease in receptor availability in heavy drinking nonsmokers as compared to control nonsmokers. However, a larger study is warranted to explore effects of heavy alcohol drinking on other variables, such as sex, smoking, and genetic make up.