Effect of monoamine oxidase inhibition on rewarding effects of nicotine in rodents

Nicotine, the primary psychoactive compound in tobacco, is responsible for the addictive effects of smoking; however, there is a paucity of information indicating whether the presence of other biological chemicals in tobacco alters nicotine's rewarding effects. It has been suggested that the addictive effects of smoking may be due, in part, to the inhibition of the pair of monoamine oxidase enzymes responsible for a significant fraction of monoamine metabolism, Monoamine Oxidase A and B (MAO-A and MAO-B). This paper reviews the current, limited literature examining the role of MAO inhibition on the rewarding effects of nicotine (e.g., self-administration) in rodents. Overall, studies with rats and mice do suggest that MAO plays a role in nicotine reward. However, results are mixed regarding the MAO subtype responsible for the rewarding effects of nicotine, most likely due to methodological variation across the limited number of studies. Important individual difference factors such as age, sex and genetics are discussed, along with relevant brain and neurotransmitter systems. Future research is needed that builds on the available literature to map out the relationship between MAO inhibition and nicotine reward. These data will enhance our understanding of the neuropharmacological effects of smoking and the value of implementing MAO inhibitors as pharmacotherapies for smoking cessation.