Understanding brain mechanisms in nicotine reinforcement.

Current understanding of the mechanisms through which nicotine acts to reinforce behavior is limited. Demonstrated interactions between nicotine and the mesolimbic dopamine system have provided the impetus for investigations of the role of this particular brain pathway in nicotine reinforcement, and preliminary studies do indeed suggest that the dopamine system might be involved in self-administration of nicotine. However, there are clearly other possible brain sites and neurotransmitter mechanisms that could be critical to reinforcement processes for nicotine. This article proposes that a broadly-based attack on the question of nicotine reinforcement would be the most fruitful; basic biological research should aim to verify the involvement of the mesolimbic dopamine system, but also to elucidate other candidate brain systems that may contribute to the reinforcing properties of nicotine.