It is generally accepted that nicotine is the major component in tobacco smoke responsible for addiction. Several studies have demonstrated that the neural mechanisms underlying nicotine addiction have much in common with those underlying the mechanisms of addiction to other drugs. Thus, it has been shown that nicotine induces conditioning place preference and self-administration across many species. Repeated treatment with nicotine also induces behavioral sensitization in rodents. These behavioral effects of nicotine seem to mediate through the meso limbic dopamine system. Smoke cessation results in an abstinence syndrome that seems to be mediated by both peripheral and central nicotinic acetylcholine receptors. In addition, other neurotransmitters systems are involved in the mediation of nicotine addiction and withdrawal. The review of the literature evidences the complexity of the behavioral, neurochemical and molecular effects of nicotine. The integration of nicotine studies across all levels will lead to a better understanding of the neurobiological mechanisms underlying the addictive actions of nicotine. The understanding of such mechanisms is crucial to the development of pharmacological agents for the treatment of tobacco addiction and withdrawal.
Nicotine; tobacco; addiction; abstinence syndrome