Background: Several lines of investigations support the idea that nicotinic acetylcholine receptors modulate neuronal pathways involved in anxiety and depression. Aims: The purpose of this study was to determine whether 3-furan-2-yl-N-p-tolyl-acrylamide, a highly selective positive allosteric modulator of α7 nicotinic acetylcholine receptors, influences anxiety-like behaviour in mice, and to determine the modulatory activity of 3-furan-2-yl-N-p-tolyl-acrylamide on mice pretreated with either nicotine or selective α7-agonists (i.e. PNU-282987 or (2.4)-dimethoxybenzylidene anabaseine dihydrochloride). Methods: The elevated plus maze and novelty suppressed feeding tests were selected to evaluate 3-furan-2-yl-N-p-tolyl-acrylamide and other nicotinic ligands on anxiety-like behaviour in mice. Results: The results indicated that: (a) 3-furan-2-yl-N-p-tolyl-acrylamide induces anxiolytic-like activity at 0.5 (elevated plus maze) and 1.0 (novelty suppressed feeding) mg/kg, respectively, after acute treatment, whereas its efficacy is increased after chronic treatments (i.e. active at 0.1 mg/kg; elevated plus maze). This is the first time showing anxiolytic-like activity elicited by 3-furan-2-yl-N-p-tolyl-acrylamide, contrary to the lack of activity for PNU-120596 (0.1 mg/kg); (b) the anxiolytic-like activity of 0.5 mg/kg 3-furan-2-yl-N-p-tolyl-acrylamide is inhibited by methyllycaconitine, a selective α7-antagonist, suggesting that α7 nicotinic acetylcholine receptors are involved in this process; (c) 0.5 mg/kg 3-furan-2-yl-N-p-tolyl-acrylamide reverses the anxiogenic effects induced by 0.1 mg/kg nicotine but not by 10.0 mg/kg PNU-282987; and (d) inactive doses of both 3-furan-2-yl-N-p-tolyl-acrylamide (0.1 mg/kg) and (2.4)-dimethoxybenzylidene anabaseine dihydrochloride (1.0 mg/kg) produce anxiolytic-like effects, suggesting drug interactions, probably synergistic. Conclusions: Our findings indicated that anxiolytic-like activity is mediated by α7 nicotinic acetylcholine receptors, supporting the concept that these receptors modulate anxiety processes. The results indicating that the chronic treatment with 3-furan-2-yl-N-p-tolyl-acrylamide is more efficient than the acute treatment in eliciting anxiolytic-like activity, and that 3-furan-2-yl-N-p-tolyl-acrylamide reverses the anxiogenic effects induced by nicotine, might be of therapeutic importance during smoking cessation.
A Novel α2/α4 Subtype-selective Positive Allosteric Modulator of Nicotinic Acetylcholine Receptors Acting from the C-tail of an α Subunit
