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Updated: Aug 15, 2026

Rodent Brain Microinjection to Study Molecular Substrates of Motivated Behavior
Published on: September 16, 2015
Monoamine oxidase inhibition dramatically increases the motivation to self-administer nicotine in rats
Karine Guillem1, Caroline Vouillac, Marc R Azar
1Laboratoire de Neuropsychobiologie des Désadaptations, Unité Mixte de Recherche 5541, Centre National de la Recherche Scientifique, Université de Bordeaux 2, 33076 Bordeaux Cedex, France.
Abstract:
Nicotine is the major neuroactive compound of tobacco, which has, by itself, weak reinforcing properties. It is known that levels of the enzymes monoamine oxidase A (MAO-A) and MAO-B are reduced in the platelets and brains of smokers and that substances, other than nicotine, present in tobacco smoke have MAO-inhibitory activities. Here, we report that inhibition of MAO dramatically and specifically increases the motivation to self-administer nicotine in rats. These effects were more prominent in rats selected for high responsiveness to novelty than in rats with low responsiveness to novelty. The results suggest that the inhibition of MAO activity by compounds present in tobacco smoke may combine with nicotine to produce the intense reinforcing properties of cigarette smoking that lead to addiction.
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