1-(Benzofuran-2-yl)-2-(3,3,3-trifluoropropyl)aminopentane HCl, 3-F-BPAP, antagonizes the enhancer effect of (-)-BPAP in the shuttle box and leaves the effect of (-)-deprenyl unchanged

Abstract The subcutaneous administration of 1 mg/kg tetrabenazine, once daily for 5 days, which depletes the catecholamine stores in the brain, significantly inhibits in rats the acquisition of a two-way conditioned avoidance reflex in the shuttle box. Enhancer substances, the tryptamine-derived selective and highly potent enhancer, R -(−)-1-(benzofuran-2-yl)-2-propylaminopentane HCl [(−)-BPAP] (0.05–10 mg/kg), the β-phenylethylamine (PEA)-derived enhancer, (−)-deprenyl (1–5 mg/kg) and the (−)-deprenyl analogue, free of MAO-B inhibitory potency, (−)-1-phenyl-2-propylaminopentane HCl [(−)-PPAP], (1–5 mg/kg), antagonize in a dose-dependent manner the inhibition of learning caused by tetrabenazine. 1-(Benzofuran 2 yl)-2-(3,3,3-trifluoropropyl)aminopentane HCl [3 F BPAP], a newly synthetized analogue of (−)-BPAP with low specific activity, significantly antagonized the enhancer effect of (−)-BPAP but left the effect of (−)-deprenyl and (−)-PPAP unchanged. This is the first proof for a difference in the mechanism of action between a PEA-derived enhancer substance and its tryptamine-derived peer.