Regulation of neuronal nicotinic receptor traffic and expression.

Neuronal nicotinic acetylcholine receptors (nAChRs) are a family of cation channels widely distributed in the brain, whose subunit composition and biophysical properties vary depending on the subtype and the area of the brain in which they are found. Brain nAChRs are also the target of nicotine, the most widespread drug of abuse. Chronic nicotine exposure differentially affects the number, subunit composition, stoichiometry and functional state of some nAChR subtypes, leaving others substantially unaffected. In this review, we will summarise recent data concerning the nAChR subtypes expressed in the CNS, and how they are regulated by means of chronic nicotine and/or nicotinic drugs. We will particularly focus on the possible mechanisms involved in the up-regulation of nAChRs.