α3β4 nicotinic acetylcholine receptors in the medial habenula modulate the mesolimbic dopaminergic response to acute nicotine in vivo

► Tested nicotinic α3β4 antagonists using in vivo microdialysis. ► Acute nicotine increased extracellular dopamine in the nucleus accumbens. ► Intra-habenular injection of α3β4 nicotinic antagonists blocked this effect. ► Habenular nicotinic receptors modulate accumbal dopamine in vivo.