GLP1R and nicotine dependence: Given that development of nicotine addiction partly depends on the effects of nicotine on the mesolimbic dopamine system (for review see [2-4]) and that we here show that Ex4 suppresses established nicotine-induced effects on the mesolimbic dopamine system [26,27,31], we hypothesize that GLP-1 receptors within these reward nodes may mediate the rewarding properties of nicotine.