Nicotine cue: lack of effect of the α7 nicotinic receptor antagonist methyllycaconitine

Abstract To assess the role of the α7 neuronal nicotinic acetylcholine receptor in the discriminative stimulus properties of (−)-nicotine, this study investigated the ability of the α7 receptor antagonist methyllycaconitine to modulate the nicotine cue. In rats trained to discriminate (−)-nicotine from saline, intraperitoneal injections of methyllycaconitine neither induced nor blocked the nicotine cue. Intracerebroventricular administration of methyllycaconitine, neither potentiated nor blocked the effect of (−)-nicotine. On the other hand, intracerebroventricular injections of mecamylamine blocked the nicotine cue. The available evidence indicate that the nicotinic acetylcholine receptors in the brain blocked by methyllycaconitine, those presumaly containing α7 subunits, do not participate in the expression of the discriminative stimulus properties of (−)-nicotine.