Habenular Synapses and Nicotine

Abstract The adaptive changes produced by repeated exposure to nicotine play a crucial role in the establishment of dependence. While many brain areas are enriched in nicotinic acetylcholine receptors (nAChRs) and participate in the addictive effects of nicotine, recently, the habenular circuit, which is highly enriched in α3β4α5 nAChRs, has emerged as a critical node for acquisition of nicotine intake and difficulties in smoking cessation. This book chapter will review the anatomical and functional connections of the medial habenula-interpeduncular nucleus (MHb-IPN) circuit and the unique molecular and electrophysiological properties of habenular synapses that underlie the neuroadaptive changes that occur in response to chronic nicotine.