Monoamine Oxidase Inhibition Increases the Motivation to Self Administer Nicotine in Rats Monoamine oxidase inhibition increases the rate of acquisition of nicotine self administration but it did not increase the rate of locomotor sensitization to nicotine or alter plasma levels of nicotine or cotinine. Effects of monoamine oxidase inhibition were larger in rats with increased locomotor reactivity to nicotine. Components of tobacco smoke inhibit monoamine oxidase and smokers have decreased monoamine oxidase activity in brain, which suggests that monoamine oxidase inhibition by tobacco smoke increases the reinforcing properties of nicotine that lead to addiction. (Constructed from data in Guillem, K. et al. J Neurosci, 25: 8593 – 8600, 2005) ©2012 NBEP