Decreased dopamine transporter availability in male smokers - A dual isotope SPECT study

Introduction: Although the mesolimbic dopaminergic system has been shown to play a role in reinforcing tobacco smoking, results of imaging studies that examine the relationship between tobacco smoking and the central dopamine system remain discrepant. To delineate the role of tobacco addiction in central pre- and post-synaptic dopaminergic activities, we analyzed the central D₂-family receptors, the dopamine transporters (DAT), and degrees of dependence in male smokers. Methods: Eleven male smokers and 11 healthy non-smokers were recruited. The striatal dopamine D₂/D₃ receptor availability was approximated using SPECT and [¹²³I] IBZM while the DAT availability was approximated using SPECT and [^99mTc] TRODAT-1. All of the smokers completed the Fagerström Test for Nicotine Dependence (FTND) and other related questionnaires. Results: A decrease in DAT availability in the striatum of male smokers is noted (p < 05). However, the striatal D₂/D₃ receptor availability in male smokers does not differ from that of non-smokers. Conclusions: These findings suggest that cigarette smoking may alter central dopamine functions in males, particularly at the pre-synaptic sites.