Nicotinic acetylcholine receptors and their role in ghrelin-producing cells.

Gastric orexigenic peptide ghrelin has been implicated in tobacco addiction, but there are conflicting results regarding the effects of acute smoke on the plasma ghrelin levels. In this study, we screened the effects of tobacco-related chemicals, especially focusing on the effects of nicotine on ghrelin regulation at cellular level. Nicotine alone modestly stimulated ghrelin secretion, and enhanced the stimulatory effects of isoproterenol and oxytocin on ghrelin secretion from ghrelin-producing MGN3-1 cells evaluated by a newly developed ghrelin-HiBiT assay system. MGN3-1 cells expressed high levels of α4β2 nicotinic acetylcholine receptor, and α4β2 selective agonist, epibatidine evoked substantial intracellular Ca2+ elevation. These results indicate that nAChR has a potential role in ghrelin secretion and ghrelin-mediated tobacco addiction.