중독성 질환으로서의 흡연

Smoking as an Addictive Disorder

Nicotine is the major substance that accounts for the addictive nature of smoking. Nicotine induces neurobiological and behavioral responses through diverse neurochemical mechanisms over the central nervous system. The brain reward system, particularly the dopaminergic pathway from the ventral tegmental area to nucleus accumbens, is central to understanding the behavioral reinforcement underlying substance addictions such as the addiction to nicotine. Nicotine acts as an agonist provoking activation or desensitization of nicotinic acetylcholine receptors in different brain areas including the brain reward system. Nicotine also indirectly influences the glutaminergic, GABAergic, noradrenergic, and serotonergic neurotransmission that lead ultimately to activation of the dopaminergic pathway in the brain reward system. Chronic exposure to nicotine activates neuroadaptation and associative learning with the nicotine-related stimulus through dopaminergic or cholinergic systems, which can lead to nicotine dependence or withdrawal. In sum, the neurobiological processes described above are deeply involved in the basis of nicotine dependence and underlie the frequent failure of attempts to quit smoking. In this review we discuss the neurobiological mechanisms of nicotine addiction focusing on the roles of the nicotinic acetylcholine receptor